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Gindrat, D. y R. Pilloud. "La pourriture fongique des tubercules de pomme de terre en atmosphère contrôlée". Potato Research 28, n.º 2 (junio de 1985): 153–60. http://dx.doi.org/10.1007/bf02357441.
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Decharme, Bertrand, Christine Delire y Aaron Boone. "La représentation des surfaces continentales dans la modélisation du climat à Météo-France". La Météorologie, n.º 108 (2020): 067. http://dx.doi.org/10.37053/lameteorologie-2020-0018.
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Les surfaces continentales jouent un rôle non négligeable dans le système climatique de la Terre. Elles occupent d'ailleurs une place majeure dans les cycles globaux de l'eau et du carbone. Elles ont été prises en compte dès les premiers modèles numériques de climat et, avec l'évolution des connaissances, des capacités de calcul et de la demande sociétale, leur représentation s'est aujourd'hui considérablement complexifiée. Nous présentons ici une brève histoire de l'évolution du modèle de surfaces Isba (Interactions sol-biosphère-atmosphère) de Météo-France dans son utilisation à l'échelle du globe en la replaçant dans le contexte international de la modélisation climatique. Land surfaces play a significant role in the Earth climate system, and they are a major component of the global carbon and water cycles. The first numerical climate models took them into account in very simple ways. Through time the complexity of their representation has increased a lot owing to improved knowledge, larger computational resources and changing societal demands. We present here a brief history of the ISBA (Interactions Soil-Biosphere-Atmosphere) land surface model developed at Météo-France when used at the global scale and how it evolved in the context of international climate modelling.
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Camus, Audrey. "Du virtuel à la romance". Études 34, n.º 1 (24 de noviembre de 2008): 109–21. http://dx.doi.org/10.7202/019408ar.
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Résumé Cet article se propose d’interroger la dimension ménippéenne de l’intertexte dont se réclame le livre de Pierre Yergeau à travers T. S. Eliot et Pétrone notamment. Une telle approche permet de saisir l’importance du problème de l’infertilité dans Du virtuel à la romance et de comprendre de quelle manière la construction intertextuelle du recueil tend à y remédier. En même temps qu’elle en éclaire la facture kaléidoscopique, elle révèle l’ambivalence fondamentale de l’oeuvre, que sa désolation apparente ne laissait tout d’abord pas deviner. Loin de se contenter de partager avec ses devanciers un thème ou une atmosphère délétère, il apparaît que Pierre Yergeau puise dans la filiation ménippéenne pour nourrir son imaginaire et fabriquer sa propre fiction, régénérant de la sorte la terre gaste contre laquelle il écrit.
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Cohen, Y. "French participation in the International Equatorial Electrojet Year". Annales Geophysicae 16, n.º 6 (30 de junio de 1998): 657. http://dx.doi.org/10.1007/s00585-998-0657-x.
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Abstract. Without abstractAcknowledgements. The IEEY studies in the African sector were made possible by the participation of a large number of institutes. Funding was provided by the Ministère Français de la Coopération (Département de la Recherche et des Formations, and Département Télécommunications); ORSTOM (Département Terre Océan Atmosphère); CNET (France-Telecom Centre Lannion); the Ministère Français de la Recherche et de la Technologie; Centre National de la Recherche Scientifique (Département Sciences de l'Univers); the Centre à l'Energie Atomique; the Université Paris-Sud; Abidjan University, Ivory Coast; Dakar University, Senegal. We would like to express our deep gratitude to the many colleagues who have participated in the success of this experiment through their enormous personal commitment, to the Editorial Board of Annales Geophysicae and particularly to Sylviane Perret for producing this special issue.
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Planchon, Olivier. "Climatologie comparée des planètes : un bref état des connaissances". Climatologie 14 (2017): 18–47. http://dx.doi.org/10.4267/climatologie.1255.
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Les principaux paramètres permettant de caractériser et comparer les conditions climatiques des différentes planètes telluriques du système solaire sont développés en fonction de la distance au Soleil, de l’existence d’une atmosphère, de sa composition et ses mouvements, et enfin des paramètres orbitaux permettant d’identifier des cycles saisonniers plus ou moins accentués (obliquité et excentricité). Les conditions climatiques des planètes du système solaire font ressortir certains traits communs modulés par les caractères propres à chaque planète. Ainsi la vitesse de rotation, l’obliquité et l’excentricité introduisent, d’une part par la durée du jour et de la nuit, d’autre part par l’existence ou non de saisons, des nuances climatiques tantôt contrastées, tantôt subtiles et complexes d’une planète à une autre. La paléoclimatologie de la Terre peut aussi apporter certaines indications permettant de modéliser les conditions climatiques probables sur d’autres planètes telluriques.
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Duru, Michel. "Transition agroécologique du système alimentaire : un enjeu de santé globale". Le Nouveau Praticien Vétérinaire élevages & santé 15, n.º 54 (2023): 60–70. http://dx.doi.org/10.1051/npvelsa/2024014.
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L’agriculture et l’alimentation sont au cœur de défis interdépendants : épuisement des ressources naturelles, pollutions, érosion de la biodiversité, dérèglement climatique, augmentation des maladies chroniques et infectieuses. De nouvelles approches intégratrices basées sur la santé sont nécessaires pour dépasser les approches « en silo » qui ne considèrent pas les multiples interdépendances entre la santé des humains, des animaux et l’environnement. Nous proposons le concept d’« Une seule santé » basé sur les interdépendances entre les santés humaine, animale, environnementale en distinguant pour cette dernière la santé des agroécosystèmes (échelle locale) et celle du « système Terre » (écosystèmes non cultivés, eau, atmosphère). De cette façon, il est possible de traiter explicitement des relations entre le système alimentaire, du champ à l’assiette, et les quatre domaines de santé, et ainsi de penser les changements à opérer pour relever les défis contemporains locaux et planétaires.
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Ologhobo, A. D. "Sustainable livestock production and the vagaries of climate change". Nigerian Journal of Animal Production 48, n.º 4 (8 de marzo de 2021): 39–58. http://dx.doi.org/10.51791/njap.v48i4.3015.
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The climates of the world are distinguished by several factors, including latitude (distance north or south of the equator), temperature (the degree of hotness or coldness of an environment), topography (the shape and height of land features), and distribution of land and sea. Climate change, marked by global warming, is basically the alteration in the balance between incoming and outgoing radiation in the Earth-Atmosphere System. Although climate change is a global phenomenon, its negative impacts are more severely felt by poor people in developing countries who rely heavily on the natural resource base for their livelihoods. Rural poor communities rely greatly for their survival on agriculture and livestock keeping that are amongst the most climate-sensitive economic sectors. Unpredictable climate change with associated disturbances are negatively affecting the livestock industry in Nigeria because as temperatures rise and fall, a wide variety of physiological, behavioural, neuro-endocrinural and molecular responses are initiated in farm animals. This has a range of far reaching effects on livestock production with grave nutritional, health and socio-economic consequences. Given the magnitude of the challenges of climate change and the need to reduce their negative effects, it is imperative to identify mitigation and adaptation measures that are easy to implement and cost effective, in order to stop all human activities that contribute to the problems of climate change and if possible, reverse the trend and attain a significant level of adaptation in vulnerable areas and sectors. The paper builds on this concept and provides strategies for promoting adaptation and mitigation activities for minimizing the effect of climate change in livestock production.
Les climats du monde se distinguent par plusieurs facteurs, notamment la latitude (distance au nord ou au sud de l'équateur), la température (le degré de chaleur ou de froid d'un environnement), la topographie (la forme et la hauteur des caractéristiques du sol) et la distribution des terre et mer. Le changement climatique, marqué par le réchauffement climatique, est essentiellement la modification de l'équilibre entre les rayonnements entrants et sortants dans le système Terre-Atmosphère. Bien que le changement climatique soit un phénomène mondial, ses impacts négatifs sont plus durement ressentis par les pauvres des pays en développement qui dépendent fortement des ressources naturelles pour leurs moyens de subsistance. Les communautés rurales pauvres dépendent beaucoup pour leur survie de l'agriculture et de l'élevage qui font partie des secteurs économiques les plus sensibles au climat. Un changement climatique imprévisible et des perturbations associées affectent négativement l'industrie de l'élevage au Nigéria car, à mesure que les températures augmentent et diminuent, une grande variété de réponses physiologiques, comportementales, neuro-endocrinurales et moléculaires sont initiées chez les animaux d'élevage. Cela a une gamme d'effets de grande portée sur la production animale avec de graves conséquences nutritionnelles, sanitaires et socio-économiques. Compte tenu de l'ampleur des défis du changement climatique et de la nécessité de réduire leurs effets négatifs, il est impératif d'identifier des mesures d'atténuation et d'adaptation faciles à mettre en œuvre et rentables, afin d'arrêter toutes les activités humaines qui contribuent aux problèmes climatiques. changer et si possible inverser la tendance et atteindre un niveau d'adaptation significatif dans les zones et secteurs vulnérables. Le document s'appuie sur ce concept et propose des stratégies pour promouvoir les activités d'adaptation et d'atténuation afin de minimiser l'effet du changement climatique sur la production animale.
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Wunderlich, Fabian, Markus Scheucher, John Lee Grenfell, Franz Schreier, Clara Sousa-Silva, Mareike Godolt y Heike Rauer. "Detectability of biosignatures on LHS 1140 b". Astronomy & Astrophysics 647 (marzo de 2021): A48. http://dx.doi.org/10.1051/0004-6361/202039663.
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Context. Terrestrial extrasolar planets around low-mass stars are prime targets when searching for atmospheric biosignatures with current and near-future telescopes. The habitable-zone super-Earth LHS 1140 b could hold a hydrogen-dominated atmosphere, and is an excellent candidate for detecting atmospheric features. Aims. In this study we investigate how the instellation and planetary parameters influence the atmospheric climate, chemistry, and spectral appearance of LHS 1140 b. We study the detectability of selected molecules, in particular potential biosignatures, with the upcoming James Webb Space Telescope (JWST) and Extremely Large Telescope (ELT). Methods. In the first step we used the coupled climate–chemistry model 1D-TERRA to simulate a range of assumed atmospheric chemical compositions dominated by molecular hydrogen (H2) and carbon dioxide (CO2). In addition, we varied the concentrations of methane (CH4) by several orders of magnitude. In the second step we calculated transmission spectra of the simulated atmospheres and compared them to recent transit observations. Finally, we determined the observation time required to detect spectral bands with low-resolution spectroscopy using JWST, and the cross-correlation technique using ELT. Results. In H2-dominated and CH4-rich atmospheres oxygen (O2) has strong chemical sinks, leading to low concentrations of O2 and ozone (O3). The potential biosignatures ammonia (NH3), phosphine (PH3), chloromethane (CH3Cl), and nitrous oxide (N2O) are less sensitive to the concentration of H2, CO2, and CH4 in the atmosphere. In the simulated H2-dominated atmosphere the detection of these gases might be feasible within 20 to 100 observation hours with ELT or JWST when assuming weak extinction by hazes. Conclusions. If further observations of LHS 1140 b suggest a thin, clear, hydrogen-dominated atmosphere, the planet would be one of the best known targets to detect biosignature gases in the atmosphere of a habitable-zone rocky exoplanet with upcoming telescopes.
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Loeb, Norman G., Bruce A. Wielicki, Wenying Su, Konstantin Loukachine, Wenbo Sun, Takmeng Wong, Kory J. Priestley, Grant Matthews, Walter F. Miller y R. Davies. "Multi-Instrument Comparison of Top-of-Atmosphere Reflected Solar Radiation". Journal of Climate 20, n.º 3 (1 de febrero de 2007): 575–91. http://dx.doi.org/10.1175/jcli4018.1.
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Abstract Observations from the Clouds and the Earth’s Radiant Energy System (CERES), Moderate Resolution Imaging Spectroradiometer (MODIS), Multiangle Imaging Spectroradiometer (MISR), and Sea-Viewing Wide-Field-of-View Sensor (SeaWiFS) between 2000 and 2005 are analyzed in order to determine if these data are meeting climate accuracy goals recently established by the climate community. The focus is primarily on top-of-atmosphere (TOA) reflected solar radiances and radiative fluxes. Direct comparisons of nadir radiances from CERES, MODIS, and MISR aboard the Terra satellite reveal that the measurements from these instruments exhibit a year-to-year relative stability of better than 1%, with no systematic change with time. By comparison, the climate requirement for the stability of visible radiometer measurements is 1% decade−1. When tropical ocean monthly anomalies in shortwave (SW) TOA radiative fluxes from CERES on Terra are compared with anomalies in Photosynthetically Active Radiation (PAR) from SeaWiFS—an instrument whose radiance stability is better than 0.07% during its first six years in orbit—the two are strongly anticorrelated. After scaling the SeaWiFS anomalies by a constant factor given by the slope of the regression line fit between CERES and SeaWiFS anomalies, the standard deviation in the difference between monthly anomalies from the two records is only 0.2 W m−2, and the difference in their trend lines is only 0.02 ± 0.3 W m−2 decade−1, approximately within the 0.3 W m−2 decade−1 stability requirement for climate accuracy. For both the Tropics and globe, CERES Terra SW TOA fluxes show no trend between March 2000 and June 2005. Significant differences are found between SW TOA flux trends from CERES Terra and CERES Aqua between August 2002 and March 2005. This discrepancy is due to uncertainties in the adjustment factors used to account for degradation of the CERES Aqua optics during hemispheric scan mode operations. Comparisons of SW TOA flux between CERES Terra and the International Satellite Cloud Climatology Project (ISCCP) radiative flux profile dataset (FD) RadFlux product show good agreement in monthly anomalies between January 2002 and December 2004, and poor agreement prior to this period. Commonly used statistical tools applied to the CERES Terra data reveal that in order to detect a statistically significant trend of magnitude 0.3 W m−2 decade−1 in global SW TOA flux, approximately 10 to 15 yr of data are needed. This assumes that CERES Terra instrument calibration remains highly stable, long-term climate variability remains constant, and the Terra spacecraft has enough fuel to last 15 yr.
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Loeb, Norman G., Seiji Kato, Konstantin Loukachine y Natividad Manalo-Smith. "Angular Distribution Models for Top-of-Atmosphere Radiative Flux Estimation from the Clouds and the Earth’s Radiant Energy System Instrument on the Terra Satellite. Part I: Methodology". Journal of Atmospheric and Oceanic Technology 22, n.º 4 (1 de abril de 2005): 338–51. http://dx.doi.org/10.1175/jtech1712.1.
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Abstract The Clouds and Earth’s Radiant Energy System (CERES) provides coincident global cloud and aerosol properties together with reflected solar, emitted terrestrial longwave, and infrared window radiative fluxes. These data are needed to improve the understanding and modeling of the interaction between clouds, aerosols, and radiation at the top of the atmosphere, surface, and within the atmosphere. This paper describes the approach used to estimate top-of-atmosphere (TOA) radiative fluxes from instantaneous CERES radiance measurements on the Terra satellite. A key component involves the development of empirical angular distribution models (ADMs) that account for the angular dependence of the earth’s radiation field at the TOA. The CERES Terra ADMs are developed using 24 months of CERES radiances, coincident cloud and aerosol retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS), and meteorological parameters from the Global Modeling and Assimilation Office (GMAO)’s Goddard Earth Observing System (GEOS) Data Assimilation System (DAS) V4.0.3 product. Scene information for the ADMs is from MODIS retrievals and GEOS DAS V4.0.3 properties over the ocean, land, desert, and snow for both clear and cloudy conditions. Because the CERES Terra ADMs are global, and far more CERES data are available on Terra than were available from CERES on the Tropical Rainfall Measuring Mission (TRMM), the methodology used to define CERES Terra ADMs is different in many respects from that used to develop CERES TRMM ADMs, particularly over snow/sea ice, under cloudy conditions, and for clear scenes over land and desert.
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Söderlund,, Maud. "Terra Caritatis: Where Suffering Is Alleviated in an Atmosphere of Community". International Journal of Human Caring 11, n.º 3 (abril de 2007): 35–44. http://dx.doi.org/10.20467/1091-5710.11.3.35.
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It is interesting to examine the concept of family care when describing relatives’ experience. This article presents a model of caring from relatives’ perspectives; it was developed using an abductive design composed of induction, deduction, and abduction. Reaching the infinite through the abductive process, it is possible to describe a model of caring from relatives’ perspectives being in the atmosphere of community where someone who really knows how it is, is present. Amodel named Terra Caritatis, through which suffering is alleviated in an atmosphere of solidarity, is developed and is presented in this article.
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Cassano, John J., Mark W. Seefeldt, Scott Palo, Shelley L. Knuth, Alice C. Bradley, Paul D. Herrman, Peter A. Kernebone y Nick J. Logan. "Observations of the atmosphere and surface state over Terra Nova Bay, Antarctica, using unmanned aerial systems". Earth System Science Data 8, n.º 1 (18 de marzo de 2016): 115–26. http://dx.doi.org/10.5194/essd-8-115-2016.
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Abstract. In September 2012 five Aerosonde unmanned aircraft were used to make measurements of the atmospheric state over the Terra Nova Bay polynya, Antarctica, to explore the details of air–sea ice–ocean coupling. A total of 14 flights were completed in September 2012. Ten of the flight missions consisted of two unmanned aerial systems (UAS) sampling the atmosphere over Terra Nova Bay on 5 different days, with one UAS focusing on the downwind evolution of the air mass and a second UAS flying transects roughly perpendicular to the low-level winds. The data from these coordinated UAS flights provide a comprehensive three-dimensional data set of the atmospheric state (air temperature, humidity, pressure, and wind) and surface skin temperature over Terra Nova Bay. The remaining UAS flights during the September 2012 field campaign included two local flights near McMurdo Station for flight testing, a single UAS flight to Terra Nova Bay, and a single UAS flight over the Ross Ice Shelf and Ross Sea polynya. A data set containing the atmospheric and surface data as well as operational aircraft data have been submitted to the United States Antarctic Program Data Coordination Center (USAP-DCC, http://www.usap-data.org/) for free access (http://gcmd.nasa.gov/getdif.htm?NSF-ANT10-43657, doi:10.15784/600125).
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Cassano, J. J., M. W. Seefeldt, S. Palo, S. L. Knuth, A. C. Bradley, P. D. Herrman, P. A. Kernebone y N. J. Logan. "Observations of the atmosphere and surface state over Terra Nova Bay, Antarctica using unmanned aircraft systems". Earth System Science Data Discussions 8, n.º 2 (1 de diciembre de 2015): 995–1019. http://dx.doi.org/10.5194/essdd-8-995-2015.
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Abstract. In September 2012 five Aerosonde unmanned aircraft were used to make measurements of the atmospheric state over the Terra Nova Bay polynya, Antarctica, to explore the details of air – sea ice – ocean coupling. A total of 14 flights were completed in September 2012. Ten of the flight missions consisted of two unmanned aircraft systems (UAS) sampling the atmosphere over Terra Nova Bay on five different days, with one UAS focusing on the downwind evolution of the air mass and a second UAS flying transects roughly perpendicular to the low level winds. The data from these coordinated UAS flights provide a comprehensive three-dimensional data set of the atmospheric state (air temperature, humidity, pressure, and wind) and surface skin temperature over Terra Nova Bay. The remaining UAS flights during the September 2012 field campaign included two local flights near McMurdo Station for flight testing, a single UAS flight to Terra Nova Bay, and a single UAS flight over the Ross Ice Shelf and Ross Sea polynya. A dataset containing the atmospheric and surface data as well as operational aircraft data has been submitted to the United States Antarctic Program Data Coordination Center (USAP-DCC, http://www.usap-data.org/) for free access (http://gcmd.nasa.gov/getdif.htm?NSF-ANT10-43657, doi:10.15784/600125).
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Shrestha, Prabhakar y Clemens Simmer. "Modeled Land Atmosphere Coupling Response to Soil Moisture Changes with Different Generations of Land Surface Models". Water 12, n.º 1 (20 de diciembre de 2019): 46. http://dx.doi.org/10.3390/w12010046.
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An idealized study with two land surface models (LSMs): TERRA-Multi Layer (TERRA-ML) and Community Land Model (CLM) alternatively coupled to the same atmospheric model COSMO (Consortium for Small-Scale Modeling), reveals differences in the response of the LSMs to initial soil moisture. The bulk parameterization of evapotranspiration pathways, which depends on the integrated soil moisture of active layers rather than on each discrete layer, results in a weaker response of the surface energy flux partitioning to changes in soil moisture for TERRA-ML, as compared to CLM. The difference in the resulting surface energy flux partitioning also significantly affects the model response in terms of the state of the atmospheric boundary layer. For vegetated land surfaces, both models behave quite differently for drier regimes. However, deeper reaching root fractions in CLM align both model responses with each other. In general, differences in the parameterization of the available root zone soil moisture, evapotranspiration pathways, and the soil-vegetation structure in the two LSMs are mainly responsible for the diverging tendencies of the simulated land atmosphere coupling responses.
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Барбин, Николай Михайлович, Лидия Вячеславовна Якупова, Дмитрий Иванович Терентьев y Валерий Таукенович Куанышев. "DECOMPOSITION OF FULLERENE C IN A NITROGEN ATMOSPHERE". Physical and Chemical Aspects of the Study of Clusters, Nanostructures and Nanomaterials, n.º 14 (15 de diciembre de 2022): 24–30. http://dx.doi.org/10.26456/pcascnn/2022.14.024.
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Проведено исследование поведения фуллерена C при нагревании в атмосфере азота. Расчеты выполнены с помощью метода термодинамического моделирования, который заключается в полном термодинамическом анализе системы с использованием программного комплекса TERRA. Диапазон минимальных и максимальных значений температур нагрева - 273-3373 K, давление 0,1 МПа. Построен график баланса углерода в системе C - N, определены протекающие химические реакции, для каждой реакции выделены температурные интервалы. Установлены температурные интервалы термической стабильности углеродных наночастиц в конденсированной и паровой фазах. В газовой фазе пар C демонстрирует повышенную термодинамическую устойчивость и только при высоких температурах вступает в реакции с парами, о чем свидетельствует резкое снижение его содержания. Рассчитаны константы равновесия реакций, а также приведены графики зависимости констант равновесия реакций от температуры. Для каждой протекающей реакции произведена аппроксимация расчетных данных линейной зависимостью. A study of the behavior of C fullerene when heated in a nitrogen atmosphere was conducted. The calculations were made using the thermodynamic modeling method, which consists in a complete thermodynamic analysis of the system using the TERRA software complex. The range of minimum and maximum heating temperatures was 273-3373 K and pressure was 0,1 MPa. A graph of the carbon balance in the C - N system was built, chemical reactions were determined, temperature intervals were allocated for each reaction. Temperature intervals of the thermal stability of carbon nanoparticles in the condensed and vapor phases are established. In the gas phase, C steam shows increased thermodynamic stability and only reacts with vapors at high temperatures, as evidenced by a sharp decrease in its content. The equilibrium constants of the reactions are calculated, and graphs of the dependence of the equilibrium constants of the reactions on temperature are given. For each reaction, the calculated data were approximated by the linear dependence.
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Loeb, Norman G., David R. Doelling, Hailan Wang, Wenying Su, Cathy Nguyen, Joseph G. Corbett, Lusheng Liang, Cristian Mitrescu, Fred G. Rose y Seiji Kato. "Clouds and the Earth’s Radiant Energy System (CERES) Energy Balanced and Filled (EBAF) Top-of-Atmosphere (TOA) Edition-4.0 Data Product". Journal of Climate 31, n.º 2 (enero de 2018): 895–918. http://dx.doi.org/10.1175/jcli-d-17-0208.1.
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The Clouds and the Earth’s Radiant Energy System (CERES) Energy Balanced and Filled (EBAF) top-of-atmosphere (TOA), Edition 4.0 (Ed4.0), data product is described. EBAF Ed4.0 is an update to EBAF Ed2.8, incorporating all of the Ed4.0 suite of CERES data product algorithm improvements and consistent input datasets throughout the record. A one-time adjustment to shortwave (SW) and longwave (LW) TOA fluxes is made to ensure that global mean net TOA flux for July 2005–June 2015 is consistent with the in situ value of 0.71 W m−2. While global mean all-sky TOA flux differences between Ed4.0 and Ed2.8 are within 0.5 W m−2, appreciable SW regional differences occur over marine stratocumulus and snow/sea ice regions. Marked regional differences in SW clear-sky TOA flux occur in polar regions and dust areas over ocean. Clear-sky LW TOA fluxes in EBAF Ed4.0 exceed Ed2.8 in regions of persistent high cloud cover. Owing to substantial differences in global mean clear-sky TOA fluxes, the net cloud radiative effect in EBAF Ed4.0 is −18 W m−2 compared to −21 W m−2 in EBAF Ed2.8. The overall uncertainty in 1° × 1° latitude–longitude regional monthly all-sky TOA flux is estimated to be 3 W m−2 [one standard deviation (1 σ)] for the Terra-only period and 2.5 W m−2 for the Terra– Aqua period both for SW and LW fluxes. The SW clear-sky regional monthly flux uncertainty is estimated to be 6 W m−2 for the Terra-only period and 5 W m−2 for the Terra– Aqua period. The LW clear-sky regional monthly flux uncertainty is 5 W m−2 for Terra only and 4.5 W m−2 for Terra– Aqua.
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Milinevsky, G., Ya Yatskiv, O. Degtyaryov, I. Syniavskyi, Yu Ivanov, A. Bovchaliuk, M. Mishchenko, V. Danylevsky, M. Sosonkin y V. Bovchaliuk. "Remote sensing of aerosol in the terrestrial atmosphere from space: new missions". Advances in Astronomy and Space Physics 5, n.º 1 (2015): 11–16. http://dx.doi.org/10.17721/2227-1481.5.11-16.
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The distribution and properties of atmospheric aerosols on a global scale are not well known in terms of determination of their effects on climate. This mostly is due to extreme variability of aerosol concentrations, properties, sources, and types. Aerosol climate impact is comparable to the effect of greenhouse gases, but its influence is more difficult to measure, especially with respect to aerosol microphysical properties and the evaluation of anthropogenic aerosol effect. There are many satellite missions studying aerosol distribution in the terrestrial atmosphere, such as MISR/Terra, OMI/Aura, AVHHR, MODIS/Terra and Aqua, CALIOP/CALIPSO. To improve the quality of data and climate models, and to reduce aerosol climate forcing uncertainties, several new missions are planned. The gap in orbital instruments for studying aerosol microphysics has arisen after the Glory mission failed during launch in 2011. In this review paper, we describe several planned aerosol space missions, including the Ukrainian project Aerosol-UA that obtains data using a multi-channel scanning polarimeter and wide-angle polarimetric camera. The project is designed for remote sensing of the aerosol microphysics and cloud properties on a global scale.
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Lovita, Oktalia Triananda, Mokhamad Nur Cahyadi y Muhammad Taufik. "Analisa Perubahan Cuaca Di Pulau Sumatera Akibat Kebakaran Hutan Dengan Data Water Vapor Dari Citra Satelit Terra Modis". Jurnal Inotera 2, n.º 1 (29 de julio de 2017): 29. http://dx.doi.org/10.31572/inotera.vol2.iss1.2017.id17.
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Forest fires in Sumatra lead to a very extreme climate changes around the earth, so there would still be a difficult job for atmosphere researchers. This research was conducted to know the weather conditions by determining the condition of Water Vapor (WV) on the island of Sumatra. Monitoring the condition of WV can be done by using remote sensing techniques, by processing the image satellite data namely Terra Modis (Moderate Resolution Imaging Spectroradiometer). Data calculation condition WV, as one of the parameters of dynamic atmosphere. The data comes from Terra Modis satellite image, the data on Canal 2, 5, 17, 18 and 19 with a wavelength range; 0,865�m, 1.24 �m, 0.905 �m, 0.936 �m and 0,940 �m. From these results obtained from the average value of Water Vapor before and after fires in 2012. Water Vapor taken from TERRA MODIS satellite imagery (y) with a correction factor of 0.9865. Although the correlation (r) between Water Vapor from MODIS data is high, it can be seen that between Water Vapor in 2012 ranged between 3-8 cm. 82%, however only about 68% of Water Vapor MODIS diversity that can be presented by the equation model to approach the actual value of Water Vapor. With these data will greatly affect the weather cycle in Indonesia.
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Wicky, Érika. "Atmosphères d’ateliers : qualité de l’air et perceptions sensorielles". Romantisme 202, n.º 4 (11 de diciembre de 2023): 41–52. http://dx.doi.org/10.3917/rom.202.0041.
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Les descriptions d’ateliers de peintres publiées au xix e siècle s’attachent très souvent à rendre compte de leur atmosphère . Réconciliant les deux acceptions figurées du terme, l’appréhension sensorielle de l’air de l’atelier permet aux auteurs d’incarner leur récit, mais aussi d’évoquer l’ambiance qui règne dans les différents ateliers et plus particulièrement leurs rapports singuliers au confort bourgeois et aux normes de la vie quotidienne. Ainsi, les descriptions sensorielles de l’atmosphère de l’atelier s’attardent en particulier à la température qui y règne, à la présence de poussière ou de fumée de tabac ainsi qu’aux vapeurs de térébenthine, émanations du travail du peintre qui se mêlent plus ou moins à des senteurs mondaines. Observer l’imaginaire de l’atelier sous l’angle sensoriel met en lumière de nouveaux aspects du travail des peintres.
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Lyapustin, A., Y. Wang, X. Xiong, G. Meister, S. Platnick, R. Levy, B. Franz et al. "Scientific impact of MODIS C5 calibration degradation and C6+ improvements". Atmospheric Measurement Techniques 7, n.º 12 (10 de diciembre de 2014): 4353–65. http://dx.doi.org/10.5194/amt-7-4353-2014.
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Abstract. The Collection 6 (C6) MODIS (Moderate Resolution Imaging Spectroradiometer) land and atmosphere data sets are scheduled for release in 2014. C6 contains significant revisions of the calibration approach to account for sensor aging. This analysis documents the presence of systematic temporal trends in the visible and near-infrared (500 m) bands of the Collection 5 (C5) MODIS Terra and, to lesser extent, in MODIS Aqua geophysical data sets. Sensor degradation is largest in the blue band (B3) of the MODIS sensor on Terra and decreases with wavelength. Calibration degradation causes negative global trends in multiple MODIS C5 products including the dark target algorithm's aerosol optical depth over land and Ångström exponent over the ocean, global liquid water and ice cloud optical thickness, as well as surface reflectance and vegetation indices, including the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). As the C5 production will be maintained for another year in parallel with C6, one objective of this paper is to raise awareness of the calibration-related trends for the broad MODIS user community. The new C6 calibration approach removes major calibrations trends in the Level 1B (L1B) data. This paper also introduces an enhanced C6+ calibration of the MODIS data set which includes an additional polarization correction (PC) to compensate for the increased polarization sensitivity of MODIS Terra since about 2007, as well as detrending and Terra–Aqua cross-calibration over quasi-stable desert calibration sites. The PC algorithm, developed by the MODIS ocean biology processing group (OBPG), removes residual scan angle, mirror side and seasonal biases from aerosol and surface reflectance (SR) records along with spectral distortions of SR. Using the multiangle implementation of atmospheric correction (MAIAC) algorithm over deserts, we have also developed a detrending and cross-calibration method which removes residual decadal trends on the order of several tenths of 1% of the top-of-atmosphere (TOA) reflectance in the visible and near-infrared MODIS bands B1–B4, and provides a good consistency between the two MODIS sensors. MAIAC analysis over the southern USA shows that the C6+ approach removed an additional negative decadal trend of Terra ΔNDVI ~ 0.01 as compared to Aqua data. This change is particularly important for analysis of vegetation dynamics and trends in the tropics, e.g., Amazon rainforest, where the morning orbit of Terra provides considerably more cloud-free observations compared to the afternoon Aqua measurements.
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Lyapustin, A., Y. Wang, X. Xiong, G. Meister, S. Platnick, R. Levy, B. Franz et al. "Science impact of MODIS C5 calibration degradation and C6+ improvements". Atmospheric Measurement Techniques Discussions 7, n.º 7 (18 de julio de 2014): 7281–319. http://dx.doi.org/10.5194/amtd-7-7281-2014.
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Abstract. The Collection 6 (C6) MODIS land and atmosphere datasets are scheduled for release in 2014. C6 contains significant revisions of the calibration approach to account for sensor aging. This analysis documents the presence of systematic temporal trends in the visible and near-infrared (500 m) bands of the Collection 5 (C5) MODIS Terra, and to lesser extent, in MODIS Aqua geophysical datasets. Sensor degradation is largest in the Blue band (B3) of the MODIS sensor on Terra and decreases with wavelength. Calibration degradation causes negative global trends in multiple MODIS C5 products including the dark target algorithm's aerosol optical depth over land and Ångström Exponent over the ocean, global liquid water and ice cloud optical thickness, as well as surface reflectance and vegetation indices, including the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). As the C5 production will be maintained for another year in parallel with C6, one objective of this paper is to raise awareness of the calibration-related trends for the broad MODIS user community. The new C6 calibration approach removes major calibrations trends in the Level 1B (L1B) data. This paper also introduces an enhanced C6+ calibration of the MODIS dataset which includes an additional polarization correction (PC) to compensate for the increased polarization sensitivity of MODIS Terra since about 2007, as well as de-trending and Terra–Aqua cross-calibration over quasi-stable desert calibration sites. The PC algorithm, developed by the MODIS ocean biology processing group (OBPG), removes residual scan angle, mirror side and seasonal biases from aerosol and surface reflectance (SR) records along with spectral distortions of SR. Using the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm over deserts, we have also developed a de-trending and cross-calibration method which removes residual decadal trends on the order of several tenths of one percent of the top-of-atmosphere (TOA) reflectance in the visible and near-infrared MODIS bands B1–B4, and provides a good consistency between the two MODIS sensors. MAIAC analysis over the southern USA shows that the C6+ approach removed an additional negative decadal trend of Terra ΔNDVI ~ 0.01 as compared to Aqua data. This change is particularly important for analysis of vegetation dynamics and trends in the tropics, e.g., Amazon rainforest, where the morning orbit Terra provides considerably more cloud-free observations compared to the afternoon Aqua measurements.
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Wu, Aisheng, Xiaoxiong Xiong, Amit Angal, Qiaozhen Mu y Sherry Li. "Assessment of the Radiometric Calibration Consistency of Reflective Solar Bands between Terra and Aqua MODIS in Upcoming Collection-7 L1B". Remote Sensing 15, n.º 19 (27 de septiembre de 2023): 4730. http://dx.doi.org/10.3390/rs15194730.
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Two MODIS sensors onboard the Terra and Aqua spacecraft have been successfully operating for over twenty-three and twenty-one years, respectively, providing the worldwide user community with high-quality imagery and radiometric Earth observations of the land, atmosphere, cryosphere, and oceans. This study provides an assessment of the radiometric calibration stability and consistency of Terra and Aqua MODIS RSB using the L1B from the upcoming Collection 7 release. Several independent vicarious approaches based on measurements from the Libya-4 desert, Dome C, DCC, and SNO are used to assess the calibration stability at the beginning of scan, nadir, and end of scan. Results indicate that both Terra and Aqua RSB are stable to within 1% over their mission periods. Comparison of the normalized reflectances with either a BRDF model or a common reference sensor provides a radiometric assessment of Terra and Aqua calibration consistency. Comparison results show the VIS/NIR bands are in good agreement around the nadir and at the beginning of the scan for all the approaches. For cases at the end of the scan, the agreement varies depending on the approach but is typically within ±2%. The differences observed in the SWIR bands are slightly larger than the VIS/NIR bands, which are likely due to their high sensitivity to atmospheric conditions and relatively larger electronic crosstalk impact on the Terra instrument.
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Smith, W. L., T. P. Charlock, R. Kahn, J. V. Martins, L. A. Remer, P. V. Hobbs, J. Redemann y C. K. Rutledge. "EOS Terra Aerosol and Radiative Flux Validation: An Overview of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment". Journal of the Atmospheric Sciences 62, n.º 4 (1 de abril de 2005): 903–18. http://dx.doi.org/10.1175/jas3398.1.
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Abstract NASA developed an Earth Observing System (EOS) to study global change and reduce uncertainties associated with aerosols and other key parameters controlling climate. The first EOS satellite, Terra, was launched in December 1999. The Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign was conducted from 10 July to 2 August 2001 to validate several Terra data products, including aerosol properties and radiative flux profiles derived from three complementary Terra instruments: the Clouds and the Earth’s Radiant Energy System (CERES), the Multiangle Imaging Spectroradiometer (MISR), and the Moderate Resolution Imaging Spectroradiometer (MODIS). CERES, MISR, and MODIS are being used to investigate the critical role aerosols play in modulating the radiative heat budget of the earth–atmosphere system. CLAMS’ primary objectives are to improve understanding of atmospheric aerosols, to validate and improve the satellite data products, and to test new instruments and measurement concepts. A variety of in situ sampling devices and passive remote sensing instruments were flown on six aircraft to characterize the state of the atmosphere, the composition of atmospheric aerosols, and the associated surface and atmospheric radiation parameters over the U.S. eastern seaboard. Aerosol particulate matter was measured at two ground stations established at Wallops Island, Virginia, and the Chesapeake Lighthouse, the site of an ongoing CERES Ocean Validation Experiment (COVE) where well-calibrated radiative fluxes and Aerosol Robotic Network (AERONET) aerosol properties have been measured since 1999. Nine coordinated aircraft missions and numerous additional sorties were flown under a variety of atmospheric conditions and aerosol loadings. On one “golden day” (17 July 2001), under moderately polluted conditions with midvisible optical depths near 0.5, all six aircraft flew coordinated patterns vertically stacked between 100 and 65 000 ft over the COVE site as Terra flew overhead. This overview presents a description of CLAMS objectives, measurements, and sampling strategies. Key results, reported in greater detail in the collection of papers found in this special issue, are also summarized.
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Wenta, Marta y John J. Cassano. "The Atmospheric Boundary Layer and Surface Conditions during Katabatic Wind Events over the Terra Nova Bay Polynya". Remote Sensing 12, n.º 24 (19 de diciembre de 2020): 4160. http://dx.doi.org/10.3390/rs12244160.
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Off the coast of Victoria Land, Antarctica an area of open water—the Terra Nova Bay Polynya (TNBP)—persists throughout the austral winter. The development of this coastal polynya is driven by extreme katabatic winds blowing down the slopes of Transantarctic Mountains. The surface-atmosphere coupling and ABL transformation during the katabatic wind events between 18 and 25 September 2012 in Terra Nova Bay are studied, using observations from Aerosonde unmanned aircraft system (UAS), numerical modeling results and Antarctic Weather Station (AWS) measurements. First, we analyze how the persistence and strength of the katabatic winds relate to sea level pressure (SLP) changes in the region throughout the studied period. Secondly, the polynya extent variations are analysed in relation to wind speed changes. We conclude that the intensity of the flow, surface conditions in the bay and regional SLP fluctuations are all interconnected and contribute to polynya development. We also analyse the Antarctic Mesoscale Prediction System (AMPS) forecast for the studied period and find out that incorrect representation of vertical ABL properties over the TNBP might be caused by overestimated sea ice concentrations (SIC) used as model input. Altogether, this research provides a unique description of TNBP development and its interactions with the atmosphere and katabatic winds.
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Kabatas, Burcu, W. Paul Menzel, Ata Bilgili y Liam E. Gumley. "Comparing Ship-Track Droplet Sizes Inferred from Terra and Aqua MODIS Data". Journal of Applied Meteorology and Climatology 52, n.º 1 (enero de 2013): 230–41. http://dx.doi.org/10.1175/jamc-d-11-0232.1.
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AbstractIn this study of ship tracks, Moderate Resolution Imaging Spectroradiometer (MODIS) measurements from late-morning (Terra) and early-afternoon (Aqua) Earth Observing System platforms are analyzed in five separate geographically distributed cases to compare estimates of the sizes (and their changes in time) of droplets associated with ship exhaust. Ship tracks are readily detected in near-infrared imagery as bright features, especially in 2.13-μm observations. The Terra “MOD06” and Aqua “MYD06” cloud products are used to determine the effective radius of the ship-track droplets; droplet age (time in the atmosphere) is estimated as a function of the distance from the ship. Terra and Aqua MODIS estimates of droplet sizes in ship-track plumes are found to be in agreement, with a correlation greater than 0.90; for the cases studied, droplet sizes in the ship plumes are between 6 and 18 μm. Moreover, the droplets’ size growth rates inferred from the length of the ship track were found to average between 0.5 and 1.0 μm h−1.
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Rusciano, Emanuela, Giorgio Budillon, Giannetta Fusco y Giancarlo Spezie. "Evidence of atmosphere–sea ice–ocean coupling in the Terra Nova Bay polynya (Ross Sea—Antarctica)". Continental Shelf Research 61-62 (julio de 2013): 112–24. http://dx.doi.org/10.1016/j.csr.2013.04.002.
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Gallée, Hubert. "Air-sea interactions over Terra Nova Bay during winter: Simulation with a coupled atmosphere-polynya model". Journal of Geophysical Research: Atmospheres 102, n.º D12 (1 de junio de 1997): 13835–49. http://dx.doi.org/10.1029/96jd03098.
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Barbin, N. M., L. V. Yakupova, D. I. Terent’ev y V. T. Kuanyshev. "Comparative analysis of thermal characteristics of higher fullerenes when heated in a nitrogen atmosphere". Journal of Physics: Conference Series 2388, n.º 1 (1 de diciembre de 2022): 012121. http://dx.doi.org/10.1088/1742-6596/2388/1/012121.
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Abstract To study the behavior of higher fullerenes Cn (n = 84, 90, 94) under thermal exposure in a nitrogen medium, a thermodynamic modeling method is used, the main task of which is to determine the phase, chemical composition and parameters of the system under study. This method consists of analyzing the system using the TERRA program, which is a further development of the ASTRA program package. For Cn-N2 systems, a comparative study of ongoing chemical reactions was carried out. Intervals of thermal stability of the condensed phase for higher fullerenes are revealed. The periods of thermal destruction in the gas phase in the systems under consideration are determined.
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Loeb, Norman G. y David R. Doelling. "CERES Energy Balanced and Filled (EBAF) from Afternoon-Only Satellite Orbits". Remote Sensing 12, n.º 8 (17 de abril de 2020): 1280. http://dx.doi.org/10.3390/rs12081280.
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The Clouds and the Earth’s Radiant Energy System (CERES) Energy Balanced and Filled (EBAF) data product uses a diurnal correction methodology to produce a shortwave (SW) top-of-atmosphere (TOA) radiative flux time series that accounts for diurnal cycle changes between CERES observation times while ensuring that the stability of the EBAF record is tied as closely as possible to CERES instrument calibration stability. The current EBAF Ed4.1 data product combines observations from Terra and Aqua after July 2002. However, the Terra satellite will start to drift in Mean Local Time (MLT) in early 2021, and Aqua’s MLT will start to drift in 2022. To ensure the EBAF record remains temporally stable, we explore the feasibility of using only CERES instruments from afternoon satellite orbits with a tight 1330 MLT after July 2002. We test this approach by directly comparing SW TOA fluxes generated after applying diurnal corrections to Aqua-only and to Terra + Aqua for 07/2002–06/2019. We find that global climatological mean SW TOA fluxes for these two cases are within 0.01 Wm−2 and the trend of the difference is < is 0.03 Wm−2 per decade.
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Ryan, Robert, Mary Pagnutti, Kara Burch, Larry Leigh, Timothy Ruggles, Changyong Cao, David Aaron, Slawomir Blonski y Dennis Helder. "The Terra Vega Active Light Source: A First Step in a New Approach to Perform Nighttime Absolute Radiometric Calibrations and Early Results Calibrating the VIIRS DNB". Remote Sensing 11, n.º 6 (24 de marzo de 2019): 710. http://dx.doi.org/10.3390/rs11060710.
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A fully automated, National Institute of Standards and Technology (NIST)-traceable artificial light source called Terra Vega has been developed to radiometrically calibrate the Visible Infrared Imaging Radiometer (VIIRS) Day Night Band (DNB) working in high gain stage (HGS) mode. The Terra Vega active point source is a calibrated integrating sphere that is only a fraction in size of a VIIRS DNB pixel. As such, it can be considered analogous to a ground-based photometric reference star. Vicarious calibrations that employ active point sources are different than those that make use of traditional extended sources and can be applyed to quantify the brightness of artificial light sources. The active source is successfully fielded, and early results indicate that it can be used to augment and validate the radiometric calibration of the VIIRS DNB HGS sensor on both the Suomi National Polar-orbiting Partnership (NPP) and NOAA-20 satellites. The VIIRS DNB HGS sensor can benefit from this technology as on-board calibration is challenging and hinges on transferring low gain stage (LGS) calibration using a solar diffuser to the medium gain stage (MGS) and HGS via regions of overlap. Current vicarious calibration methods that use a lunar-illuminated extended source estimate the HGS radiometric accuracy to within 8-15%. By comparison, early results and analysis showed that Terra Vega is stable to about 1%. Under clear dark night conditions, predicted top-of-atmosphere radiance from Terra Vega ranged between 1–11% of VIIRS measured values. Terra Vega’s excellent stability opens up new opportunities to validate and develop nighttime imaging applications based on point sources.
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Brooke, Jennifer K., R. Chawn Harlow, Russell L. Scott, Martin J. Best, John M. Edwards, Jean-Claude Thelen y Mark Weeks. "Evaluating the Met Office Unified Model land surface temperature in Global Atmosphere/Land 3.1 (GA/L3.1), Global Atmosphere/Land 6.1 (GA/L6.1) and limited area 2.2 km configurations". Geoscientific Model Development 12, n.º 4 (29 de abril de 2019): 1703–24. http://dx.doi.org/10.5194/gmd-12-1703-2019.
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Abstract. A limitation of the Met Office operational data assimilation scheme is that surface-sensitive infrared satellite sounding channels cannot be used during daytime periods where numerical weather prediction (NWP) model background land surface temperature (LST) biases are greater than 2 K in magnitude. The Met Office Unified Model (UM) has a significant cold LST bias in semi-arid regions when compared with satellite observations; a range of UM configurations were assessed with different model resolutions, land surface cover datasets and bare soil parameterisations. UM LST biases were evaluated at global resolution and in a limited area model (LAM) at a 2.2 km resolution over the SALSTICE (Semi-Arid Land Surface Temperature and IASI Calibration Experiment) experimental domain in south-eastern Arizona. This validation is in conjunction with eddy-covariance flux tower measurements. LST biases in the Global Atmosphere/Land 3.1 (GA/L3.1) configuration were largest in the mid-morning with respect to Moderate Resolution Imaging Spectroradiometer (MODIS) Terra (-13.6±2.8 K at the Kendall Grassland site). The diurnal cycle of LST in Global Atmosphere/Land 6.1 (GA/L6.1) showed a significant improvement relative to GA/L3.1 with the cold LST biases reduced to -1.4±2.7 K and -3.6±3.0 K for Terra and Aqua overpasses, respectively. The higher-resolution LAM showed added value over the global configurations. The spatial distribution of the LST biases relative to MODIS and the modelled bare soil cover fraction were found to be moderately correlated (0.61±0.08) during the daytime, which suggests that regions of cold LST bias are associated with low bare soil cover fraction. Coefficients of correlation with the shrub surface fractions followed the same trend as the bare soil cover fraction, although with a less significant correlation (0.36±0.09), and indicated that the sparse vegetation canopies in south-eastern Arizona are not well represented in UM ancillary datasets. The x component of the orographic slope was positively correlated with the LST bias (0.41±0.05 for MODIS Aqua) and identified that regions of cold model LST bias are found on easterly slopes, and regions of warm model LST bias are found on westerly slopes. An overestimate in the modelled turbulent heat and moisture fluxes at the eddy-covariance flux sites was found to be coincident with an underestimate in the ground heat flux.
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Dall’Oglio, G. "Italian observatory in Antarctica". Highlights of Astronomy 9 (1992): 591. http://dx.doi.org/10.1017/s1539299600022619.
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The Infrared and Submillimetric OASI Observatory is the first permanent telescope installed in Antarctica. The installation was completed in 1989 at Terra Nova Bay. The diameter of the primary mirror is 2.6 m and the receiver is a cryogenic multichannel bolometric photometer. The OASI Observatory takes advantage of the privileged position in Antarctica, where the atmosphere is very clear and the transmission is very high (≥ 90% at 2 mm wavelength). It has been designed mainly to investigate the small scale anisotropics of the Cosmic Background Radiation and Galactic and extragalactic diffuse emission.
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Loeb, Norman G., Seiji Kato, Konstantin Loukachine, Natividad Manalo-Smith y David R. Doelling. "Angular Distribution Models for Top-of-Atmosphere Radiative Flux Estimation from the Clouds and the Earth’s Radiant Energy System Instrument on the Terra Satellite. Part II: Validation". Journal of Atmospheric and Oceanic Technology 24, n.º 4 (1 de abril de 2007): 564–84. http://dx.doi.org/10.1175/jtech1983.1.
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Abstract Errors in top-of-atmosphere (TOA) radiative fluxes from the Clouds and the Earth’s Radiant Energy System (CERES) instrument due to uncertainties in radiance-to-flux conversion from CERES Terra angular distribution models (ADMs) are evaluated through a series of consistency tests. These tests show that the overall bias in regional monthly mean shortwave (SW) TOA flux is less than 0.2 W m−2 and the regional RMS error ranges from 0.70 to 1.4 W m−2. In contrast, SW TOA fluxes inferred using theoretical ADMs that assume clouds are plane parallel are overestimated by 3–4 W m−2 and exhibit a strong latitudinal dependence. In the longwave (LW), the bias error ranges from 0.2 to 0.4 W m−2 and regional RMS errors remain smaller than 0.7 W m−2. Global mean albedos derived from ADMs developed during the Earth Radiation Budget Experiment (ERBE) and applied to CERES measurements show a systematic increase with viewing zenith angle of 4%–8%, while albedos from the CERES Terra ADMs show a smaller increase of 1%–2%. The LW fluxes from the ERBE ADMs show a systematic decrease with viewing zenith angle of 2%–2.4%, whereas fluxes from the CERES Terra ADMs remain within 0.7%–0.8% at all angles. Based on several months of multiangle CERES along-track data, the SW TOA flux consistency between nadir- and oblique-viewing zenith angles is generally 5% (<17 W m−2) over land and ocean and 9% (26 W m−2) in polar regions, and LW TOA flux consistency is approximate 3% (7 W m−2) over all surfaces. Based on these results and a theoretically derived conversion between TOA flux consistency and TOA flux error, the best estimate of the error in CERES TOA flux due to the radiance-to-flux conversion is 3% (10 W m−2) in the SW and 1.8% (3–5 W m−2) in the LW. Monthly mean TOA fluxes based on ERBE ADMs are larger than monthly mean TOA fluxes based on CERES Terra ADMs by 1.8 and 1.3 W m−2 in the SW and LW, respectively.
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Audah, Safridatul, Mokhamad Nur Cahyadi y Muhammad Taufik. "Analisa Penentuan Water Vapor Terhadap Pengaruh Erupsi Gunung Sinabung Menggunakan Data SUGAR Dan Citra Satelit Terra MODISs". Jurnal Inotera 2, n.º 1 (29 de julio de 2017): 37. http://dx.doi.org/10.31572/inotera.vol2.iss1.2017.id18.
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The eruption of Mount Sinabung in 2010 caused bursts of volcanic ash particles into the atmosphere layer to impact the weather. This is because volcanic ash is hydrocopic which can cause condensation process and block the process of solar radiation earth surface. Precivitable Water vapor (PWV) as one of the parameters of the atmosphere that can be used as information to determine the weather conditions in an area. Utilization of data Sumatran GPS Array (SUGAR) and data satellite Terra sensors MODIS (Moderate Resolution Imaging Spektroradiometer) can be used to find out PWV through GPS inversion method by utilizing estimated estimation of slowing and rotating GPS signals overlaid with troposphere. While the transmittance method is performed by comparing the surface reflectance between the channel absorption and the channel non absorption contained in the sensor MODIS. The results showed that spatial variation of PWV distribution pattern showed wetness pattern during eruption. This was indicated by some areas that have PWV distribution pattern almost in each region and PWV verification result from GPS showed � 47.65 mm-66.81 mm, while PWV value from MODIS ranges from � 13.02 mm - 80.05 mm. Based on the results of PWV-GPS correlation test from June to October of 2010 has a correlation coefficient of 0.0173 to PWV from MODIS and explains the positive relationship between PWV of GPS with PWV value from MODIS, but correlation value of the variable variables including low category because of location points Station SUGAR are spread unevenly and are more likely to spread along the western coast of Sumatra, which borders the Indian Ocean.
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Dinoi, Adelaide, Daniel Gulli, Ivano Ammoscato, Claudia R. Calidonna y Daniele Contini. "Impact of the Coronavirus Pandemic Lockdown on Atmospheric Nanoparticle Concentrations in Two Sites of Southern Italy". Atmosphere 12, n.º 3 (8 de marzo de 2021): 352. http://dx.doi.org/10.3390/atmos12030352.
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During the new coronavirus infection outbreak, the application of strict containment measures entailed a decrease in most human activities, with the consequent reduction of anthropogenic emissions into the atmosphere. In this study, the impact of lockdown on atmospheric particle number concentrations and size distributions is investigated in two different sites of Southern Italy: Lecce and Lamezia Terme, regional stations of the GAW/ACTRIS networks. The effects of restrictions are quantified by comparing submicron particle concentrations, in the size range from 10 nm to 800 nm, measured during the lockdown period and in the same period of previous years, from 2015 to 2019, considering three time intervals: prelockdown, lockdown and postlockdown. Different percentage reductions in total particle number concentrations are observed, −19% and −23% in Lecce and −7% and −4% in Lamezia Terme during lockdown and postlockdown, respectively, with several variations in each subclass of particles. From the comparison, no significant variations of meteorological factors are observed except a reduction of rainfall in 2020, which might explain the higher levels of particle concentrations measured during prelockdown at both stations. In general, the results demonstrate an improvement of air quality, more conspicuous in Lecce than in Lamezia Terme, during the lockdown, with a differed reduction in the concentration of submicronic particles that depends on the different types of sources, their distance from observational sites and local meteorology.
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DESIKAN, V., V. R. CHIVATE y V. V. ABIHYANKAR. "Reaction of radiometric parameters to atmospheric pollution: Part I - Variation over time". MAUSAM 45, n.º 1 (1 de enero de 2022): 79–86. http://dx.doi.org/10.54302/mausam.v45i1.1888.
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The drive for indust rial development h... ... 100 to large scale urbanisation and result,.-. d in theinjec tion of good amount of suspended particle.. and gaseous substances into the atmosphere. The m..er-abuscof the capac ity .of the atmosphere to sustain the equilibrium is bound to disturb the heal budget of the earthatmospheresystem. Radiometric parameters of the atmosphere give an early indication of the trends in the longtermclimatic changes. Whi le the global rad iant exposure is no t likely to show perceptible changes due to theincreased scauering by the pollutants, I ~ ~ diffuse radiant el(p(ls~re and the direct so.l3! irradianc~ respond qu icklyto the changes In the atmospheric conditions. Various controlling factors like humidity. soi l moist ure and cloud"have d ifferent effects on the terres trial radiant energy and the changes in thi s energy OI..'Cur slowly and ta ke longtime to affect the climate at a place. But the general trend is indicated by the increased diffuse component in thedi rect sola r rrmdiances and in the net outgoing terrestrial radia nt energy. The responses arc clearly indicative.part icularly ,II Punc......here the industrial activiti es grew at a phenomenal rate during the past fifteen years.
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Rutan, David A., Seiji Kato, David R. Doelling, Fred G. Rose, Le Trang Nguyen, Thomas E. Caldwell y Norman G. Loeb. "CERES Synoptic Product: Methodology and Validation of Surface Radiant Flux". Journal of Atmospheric and Oceanic Technology 32, n.º 6 (junio de 2015): 1121–43. http://dx.doi.org/10.1175/jtech-d-14-00165.1.
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AbstractThe Clouds and the Earth’s Radiant Energy System Synoptic (SYN1deg), edition 3, product provides climate-quality global 3-hourly 1° × 1°gridded top of atmosphere, in-atmosphere, and surface radiant fluxes. The in-atmosphere surface fluxes are computed hourly using a radiative transfer code based upon inputs from Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS), 3-hourly geostationary (GEO) data, and meteorological assimilation data from the Goddard Earth Observing System. The GEO visible and infrared imager calibration is tied to MODIS to ensure uniform MODIS-like cloud properties across all satellite cloud datasets. Computed surface radiant fluxes are compared to surface observations at 85 globally distributed land (37) and ocean buoy (48) sites as well as several other publicly available global surface radiant flux data products. Computed monthly mean downward fluxes from SYN1deg have a bias (standard deviation) of 3.0 W m−2 (5.7%) for shortwave and −4.0 W m−2 (2.9%) for longwave compared to surface observations. The standard deviation between surface downward shortwave flux calculations and observations at the 3-hourly time scale is reduced when the diurnal cycle of cloud changes is explicitly accounted for. The improvement is smaller for surface downward longwave flux owing to an additional sensitivity to boundary layer temperature/humidity, which has a weaker diurnal cycle compared to clouds.
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Su, W., J. Corbett, Z. Eitzen y L. Liang. "Next-generation angular distribution models for top-of-atmosphere radiative flux calculation from CERES instruments: validation". Atmospheric Measurement Techniques 8, n.º 8 (14 de agosto de 2015): 3297–313. http://dx.doi.org/10.5194/amt-8-3297-2015.
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Abstract. Radiative fluxes at the top of the atmosphere (TOA) from the Clouds and the Earth's Radiant Energy System (CERES) instrument are fundamental variables for understanding the Earth's energy balance and how it changes with time. TOA radiative fluxes are derived from the CERES radiance measurements using empirical angular distribution models (ADMs). This paper evaluates the accuracy of CERES TOA fluxes using direct integration and flux consistency tests. Direct integration tests show that the overall bias in regional monthly mean TOA shortwave (SW) flux is less than 0.2 Wm−2 and the RMSE is less than 1.1 Wm−2. The bias and RMSE are very similar between Terra and Aqua. The bias in regional monthly mean TOA LW fluxes is less than 0.5 Wm−2 and the RMSE is less than 0.8 Wm−2 for both Terra and Aqua. The accuracy of the TOA instantaneous flux is assessed by performing tests using fluxes inverted from nadir- and oblique-viewing angles using CERES along-track observations and temporally and spatially matched MODIS observations, and using fluxes inverted from multi-angle MISR observations. The averaged TOA instantaneous SW flux uncertainties from these two tests are about 2.3 % (1.9 Wm−2) over clear ocean, 1.6 % (4.5 Wm−2) over clear land, and 2.0 % (6.0 Wm−2) over clear snow/ice; and are about 3.3 % (9.0 Wm−2), 2.7 % (8.4 Wm−2), and 3.7 % (9.9 Wm−2) over ocean, land, and snow/ice under all-sky conditions. The TOA SW flux uncertainties are generally larger for thin broken clouds than for moderate and thick overcast clouds. The TOA instantaneous daytime LW flux uncertainties derived from the CERES-MODIS test are 0.5 % (1.5 Wm−2), 0.8 % (2.4 Wm−2), and 0.7 % (1.3 Wm−2) over clear ocean, land, and snow/ice; and are about 1.5 % (3.5 Wm−2), 1.0 % (2.9 Wm−2), and 1.1 % (2.1 Wm−2) over ocean, land, and snow/ice under all-sky conditions. The TOA instantaneous nighttime LW flux uncertainties are about 0.5–1 % (< 2.0 Wm−2) for all surface types. Flux uncertainties caused by errors in scene identification are also assessed by using the collocated CALIPSO, CloudSat, CERES and MODIS data product. Errors in scene identification tend to underestimate TOA SW flux by about 0.6 Wm−2 and overestimate TOA daytime (nighttime) LW flux by 0.4 (0.2) Wm−2 when all CERES viewing angles are considered.
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Sporre, Moa K., Ewan J. O'Connor, Nina Håkansson, Anke Thoss, Erik Swietlicki y Tuukka Petäjä. "Comparison of MODIS and VIIRS cloud properties with ARM ground-based observations over Finland". Atmospheric Measurement Techniques 9, n.º 7 (21 de julio de 2016): 3193–203. http://dx.doi.org/10.5194/amt-9-3193-2016.
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Abstract. Cloud retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard the satellites Terra and Aqua and the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard the Suomi-NPP satellite are evaluated using a combination of ground-based instruments providing vertical profiles of clouds. The ground-based measurements are obtained from the Atmospheric Radiation Measurement (ARM) programme mobile facility, which was deployed in Hyytiälä, Finland, between February and September 2014 for the Biogenic Aerosols – Effects on Clouds and Climate (BAECC) campaign. The satellite cloud parameters cloud top height (CTH) and liquid water path (LWP) are compared with ground-based CTH obtained from a cloud mask created using lidar and radar data and LWP acquired from a multi-channel microwave radiometer. Clouds from all altitudes in the atmosphere are investigated. The clouds are diagnosed as single or multiple layer using the ground-based cloud mask. For single-layer clouds, satellites overestimated CTH by 326 m (14 %) on average. When including multilayer clouds, satellites underestimated CTH by on average 169 m (5.8 %). MODIS collection 6 overestimated LWP by on average 13 g m−2 (11 %). Interestingly, LWP for MODIS collection 5.1 is slightly overestimated by Aqua (4.56 %) but is underestimated by Terra (14.3 %). This underestimation may be attributed to a known issue with a drift in the reflectance bands of the MODIS instrument on Terra. This evaluation indicates that the satellite cloud parameters selected show reasonable agreement with their ground-based counterparts over Finland, with minimal influence from the large solar zenith angle experienced by the satellites in this high-latitude location.
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Garrigues, Sebastien, Samuel Remy, Julien Chimot, Melanie Ades, Antje Inness, Johannes Flemming, Zak Kipling et al. "Monitoring multiple satellite aerosol optical depth (AOD) products within the Copernicus Atmosphere Monitoring Service (CAMS) data assimilation system". Atmospheric Chemistry and Physics 22, n.º 22 (18 de noviembre de 2022): 14657–92. http://dx.doi.org/10.5194/acp-22-14657-2022.
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Abstract. The Copernicus Atmosphere Monitoring Service (CAMS) provides near-real-time forecast and reanalysis of aerosols using the ECMWF Integrated Forecasting System with atmospheric composition extension, constrained by the assimilation of MODIS and the Polar Multi-Sensor Aerosol Optical Properties (PMAp) aerosol optical depth (AOD). The objective of this work is to evaluate two new near-real-time AOD products to prepare for their assimilation into CAMS, namely the Copernicus AOD (collection 1) from the Sea and Land Surface Temperature Radiometer (SLSTR) on board Sentinel 3-A/B over ocean and the NOAA EPS AOD (v2.r1) from VIIRS on board S-NPP and NOAA20 over both land and ocean. The differences between MODIS (C6.1), PMAp (v2.1), VIIRS (v2.r1), and SLSTR (C1) AOD as well as their departure from the modeled AOD were assessed at the model grid resolution (i.e., level-3) using the 3-month AOD average (December 2019–February 2020 and March–May 2020). VIIRS and MODIS show the best consistency across the products, which is explained by instrument and retrieval algorithm similarities. VIIRS AOD is frequently lower over the ocean background and higher over biomass burning and dust source land regions compared to MODIS. VIIRS shows larger spatial coverage over land and resolves finer spatial structures such as the transport of Australian biomass burning smoke over the Pacific, which can be explained by the use of a heavy aerosol detection test in the retrieval algorithm. Our results confirm the positive offset over ocean (i) between Terra/MODIS and Aqua/MODIS due to the non-corrected radiometric calibration degradation of Terra/MODIS in the Dark Target algorithm and (ii) between SNPP/VIIRS and NOAA20/VIIRS due to the positive bias in the solar reflective bands of SNPP/VIIRS. SLSTR AOD shows much smaller level-3 values than the rest of the products, which is mainly related to differences in spatial representativity at the IFS grid spatial resolution due to the stringent cloud filtering applied to the SLSTR radiances. Finally, the geometry characteristics of the instrument, which drive the range of scattering angles sampled by the instrument, can explain a large part of the differences between retrievals such as the positive offset between PMAp datasets from MetOp-B and MetOp-A.
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Benas, N., N. Hatzianastassiou, C. Matsoukas, A. Fotiadi, N. Mihalopoulos y I. Vardavas. "Aerosol shortwave direct radiative effect and forcing based on MODIS Level 2 data in the Eastern Mediterranean (Crete)". Atmospheric Chemistry and Physics 11, n.º 24 (15 de diciembre de 2011): 12647–62. http://dx.doi.org/10.5194/acp-11-12647-2011.
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Abstract. The shortwave (SW) radiation budget was computed on a 10 km × 10 km resolution above FORTH-CRETE AERONET station in Crete, Greece, for the 11-year period from 2000 to 2010. The area is representative of the Eastern Mediterranean region, where air pollution and diminishing water resources are exacerbated by high aerosol loads and climate change. The present study aims to quantify the aerosol direct effect and forcing on the local surface and atmospheric energy budget. A radiative transfer model was used, with climatological data from the Moderate Resolution Imaging Spectroradiometer (MODIS), on board NASA's Terra and Aqua satellites. The instantaneous radiative fluxes were computed for satellite overpass times at the surface, within the atmosphere and at the top of atmosphere (TOA). Downward surface fluxes and aerosol input data were validated against ground measurements. Output fluxes reveal the direct radiative effects of dust events, with instantaneous values reaching up to −215, 139 and −46 Wm−2 at the surface (cooling), within the atmosphere (warming) and at TOA (cooling), respectively. Mean monthly values show a decreasing trend of the aerosol direct radiative effect, in agreement with a similar trend in AOT. The analysis of the contribution of anthropogenic and natural aerosol show major peaks of natural aerosol direct effect occurring mainly in spring, while a summer maximum is attributed to anthropogenic aerosol. During their peaks, anthropogenic aerosol forcing can reach values of −24 Wm−2 at the surface, 19 Wm−2 in the atmosphere and over −4 Wm−2 at TOA (monthly mean instantaneous values). The corresponding monthly peak values for natural aerosol are over −20 Wm−2, 12 Wm−2 and −9 Wm−2.
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Budillon, G. y G. Spezie. "Thermohaline structure and variability in the Terra Nova Bay polynya, Ross Sea". Antarctic Science 12, n.º 4 (diciembre de 2000): 493–508. http://dx.doi.org/10.1017/s0954102000000572.
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Hydrological measurements from three cruises during the summers 1994/95, 1995/96 and 1997/98 in the western sector of the Ross Sea allow summer and year to year changes in heat and salt content in the Terra Nova Bay polynya to be analysed. Changes in the surface layer (upper pycnocline) followed the expected seasonal pattern of warming and freshening from the beginning to the end of the summer. These near-surface changes, expressed as net heating and salting rate, were about 11 W m−2 and -6 mg salt m−2 s−1. The heating changes were substantially lower than the estimated heat supplied by the atmosphere during the summer, which underlines the importance for this season of the advective component carried by the currents in the total heat budget. The year to year differences were about one or two orders of magnitude smaller than the seasonal changes in the surface layer. In the intermediate and deep layers, the summer heat and salt variability were of the same order as or one order higher than from one summer to the next. The differences in sign and magnitude for the heat change in the upper and in the lower pycnocline indicate a weak connection in the summer period between the surface heat fluxes and the deep waters. A local source of very cold water (with temperatures below the surface freezing point) of about 0.3 Sv has been detected close to the Terra Nova Bay coast. It arose out of the interaction of the shallow–intermediate layers of High Salinity Shelf Water with the coastal glaciers. The presence and the variability of this cold water point to the significant role of the thermohaline properties of Terra Nova Bay waters in controlling the floating glacier by governing the basal melting processes.
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Shankar, Mohan, Wenying Su, Natividad Manalo-Smith y Norman G. Loeb. "Generation of a Seamless Earth Radiation Budget Climate Data Record: A New Methodology for Placing Overlapping Satellite Instruments on the Same Radiometric Scale". Remote Sensing 12, n.º 17 (27 de agosto de 2020): 2787. http://dx.doi.org/10.3390/rs12172787.
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The Clouds and the Earth’s Radiant Energy System (CERES) instruments have enabled the generation of a multi-decadal Earth radiation budget (ERB) climate data record (CDR) at the top of the Earth’s atmosphere, within the atmosphere, and at the Earth’s surface. Six CERES instruments have been launched over the course of twenty years, starting in 1999. To seamlessly continue the data record into the future, there is a need to radiometrically scale observations from newly launched instruments to observations from the existing data record. In this work, we describe a methodology to place the CERES Flight Model (FM) 5 instrument on the Suomi National Polar-orbiting Partnership (SNPP) spacecraft on the same radiometric scale as the FM3 instrument on the Aqua spacecraft. We determine the required magnitude of radiometric scaling by using spatially and temporally matched observations from these two instruments and describe the process to radiometrically scale SNPP/FM5 to Aqua/FM3 through the instrument spectral response functions. We also present validation results after application of this radiometric scaling and demonstrate the long-term consistency of the SNPP/FM5 record in comparison with the CERES instruments on Aqua and Terra.
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Bridhikitti, Arika, Pakorn Petchpayoon y Thayukorn Prabamroong. "Integrated Remote Sensing Observations of Radiative Properties and Sources of the Aerosols in Southeast Asia: The Case of Thailand". Remote Sensing 15, n.º 22 (10 de noviembre de 2023): 5319. http://dx.doi.org/10.3390/rs15225319.
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Aerosols in Southeast Asia (SEA) are entangled with complex land–sea–atmosphere–human interactions, and it is difficult for scientists to understand their dynamic behaviors. This study aims to provide an insightful understanding of aerosols across SEA with respect to their radiative properties using several lines of evidence obtained from remote sensing instruments, including those from onboard Earth observation satellites (MODIS/Terra and MODIS/Aqua, CALIOP/CALIPSO) and from ground-based observation (AERONET). The findings, obtained from cluster analysis of aerosol optical properties, showed seven aerosol types which were dominant across the country, exhibiting diverse radiative forcing potentials. The light-absorbing (prone to warm the atmosphere) aerosols were likely found in mainland SEA, both for background and high-aerosol events. The light-scattering aerosols were associated with aging processes and hygroscopic growth. The neutral potential, which comprised a mixture of oceanic and local anthropogenic aerosols, was predominant in background aerosols in insular SEA. Further studies should focus on carbonaceous aerosols (organic carbons, black carbon, and brown carbon), the aging processes, and the hygroscopic growth of these aerosols, since they play significant roles in the regional aerosol optical properties.
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Johnsen, K. P., H. T. Mengelkamp y S. Huneke. "Multi-objective calibration of the land surface scheme TERRA/LM using LITFASS-2003 data". Hydrology and Earth System Sciences 9, n.º 6 (31 de diciembre de 2005): 586–96. http://dx.doi.org/10.5194/hess-9-586-2005.
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Abstract. The turbulent sensible and latent heat fluxes simulated in the operational weather forecast model LM have been checked with data from the field experiment LITFASS 2003 (Lindenberg Inhomogeneous Terrain - Fluxes between Atmosphere and Surface: a Long-term Study) using both single site measurements and grid box aggregated fluxes. SCE-UA (single objective) and MOSCEM-UA (multi-objective) approaches were applied to calibrate the land-surface scheme TERRA/LM for 11 single sites and for the aggregated fluxes. A large variation is seen among the parameter sets found by calibration but no typical classification according to vegetation type is obvious. This is attributed to the calibrated parameter sets correcting for model deficiencies and data errors rather than describing the physical characteristics of the measurement site. The measured fluxes were combined into a time series of aggregated fluxes by the tile method. Calibration of TERRA/LM with respect to the averaged fluxes resulted in a range of parameter sets which all simulated the area-averaged fluxes in much better agreement with the observed fluxes than the standard parameter set of the operational model. A modified Nash-Sutcliffe measure as a coincidence criterion fell from 0.3 to a range between 0.15 and 0.28 for the latent heat flux and from 0.43 to between 0.26 and 0.36 for the sensible heat flux when the calibrated parameter sets were used instead of the standard parameters.
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Ovando, Gustavo, Silvina Sayago y Mónica Bocco. "Developing machine learning models for air temperature estimation using MODIS data". AgriScientia 39, n.º 1 (30 de junio de 2022): 15–28. http://dx.doi.org/10.31047/1668.298x.v39.n1.33225.
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Air temperature is a key variable in a wide range of environmental applications, including land–atmosphere interaction, climate change research and hydrology and crop growth models, among others. The objective of this study was to estimate daily maximum (Tmax) and minimum (Tmin) temperatures, based on MODIS AQUA/TERRA land surface temperature (LST), NDVI, extraterrestrial solar radiation and precipitation data. Artificial neural networks (ANN) and random forests (RF) models were developed to predict these temperatures covering weather stations in Córdoba (Argentina) for 2018-2020. The results show that RF and ANN machine learning algorithms are capable of modeling non-linear relationships between registered temperatures and LST MODIS data, in a very robust way. The validation of the models confirms that Tmax and Tmin can be accurately estimated using, jointly or separately, AQUA and TERRA LST. The best models present determination coefficients equal to 0.81/0.91 and root mean square error of 2.7/2.1 ºC for Tmax/Tmin, when using AQUA LST day/night satellite overpass time data, respectively. The robustness and confidence of the models developed, and the ease and free accessibility of input data at a global scale, suggest that these methodologies have the potential to be applied to other regions.
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RIVA, S. DALLA, M. L. ABELMOSCHI, M. CHIANTORE, M. GROTTI, E. MAGI y F. SOGGIA. "Biogeochemical cycling of Pb in the coastal marine environment at Terra Nova Bay, Ross Sea". Antarctic Science 15, n.º 4 (diciembre de 2003): 425–32. http://dx.doi.org/10.1017/s0954102003001524.
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The biogeochemical cycle of lead in the marine coastal environment of Terra Nova Bay has been investigated by determining the lead concentration in a large number of matrices: marine sediments, pack ice, snow, seawater, marine microlayer, aerosol and eight species of marine organisms (the bivalve molluscs Adamussium colbecki and Laternula elliptica, the seastar Odontaster validus, the sea urchin Sterechinus neumayeri, the fish Trematomus bernacchii, the seaweeds Iridaea cordata and Phyllophora antarctica, and the nemertine worm Parborlasia corrugatus). The study of solid speciation of sediment showed that the site is not influenced by human activity and is hence suitable to examine natural processes. The concentration values found in the suspended paniculate matter (SPM) of pack ice core, aerosol, marine microlayer and seawater as well as the particulate morphology, investigated by SEM, seem to support the hypothesis that particulate lead is transferred from the atmosphere to the water column through three different mechanisms: (i) release of SPM from the pack ice during its melting, (ii) input from the continental land through wet deposition, (iii) transport by aerosol and marine microlayer. Concentration data both in the whole organism and in some target organs indicated two suitable biomonitor organisms: the bivalva Laternula elliptica (particularly its digestive gland) and the fish Trematomus bernacchii (particularly its bones).
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Benas, N., N. Hatzianastassiou, C. Matsoukas, A. Fotiadi, N. Mihalopoulos y I. Vardavas. "Aerosol shortwave daily radiative effect and forcing based on MODIS Level 2 data in the Eastern Mediterranean (Crete)". Atmospheric Chemistry and Physics Discussions 11, n.º 7 (12 de julio de 2011): 19881–925. http://dx.doi.org/10.5194/acpd-11-19881-2011.
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Abstract. The mean daily shortwave (SW) radiation budget was computed on a 10 km × 10 km resolution above FORTH-CRETE AERONET station in Crete, Greece, for the 9-yr period from 2000 to 2008. The area is representative of the Eastern Mediterranean region, where air pollution and diminishing water resources are exacerbated by high aerosol loads and climate change. The present study aims to quantify the aerosol direct effect and forcing on the local energy budget. A radiative transfer model was used, with daily climatological data from the Moderate Resolution Imaging Spectroradiometer (MODIS), on board NASA's Terra and Aqua satellites. The radiative fluxes were computed at the surface, within the atmosphere and at the top of atmosphere (TOA). Downward surface fluxes and aerosol optical thickness (AOT) were validated against ground measurements. Daily fluxes reveal the direct radiative effects of dust events, with mean daily values reaching up to −100, 55 and −30 W m−2 at the surface (cooling), within the atmosphere (warming) and at TOA (cooling), respectively. Mean monthly values show a decreasing trend of the aerosol direct radiative effect, in agreement with a similar trend in AOT. The analysis of the contribution of anthropogenic and natural aerosol show major peaks of natural aerosol direct effect occurring mainly in spring, while a summer maximum is attributed to anthropogenic aerosol. During their peaks, anthropogenic aerosol forcing can reach values of −15 W m−2 at the surface, 8 W m−2 in the atmosphere and over −4 W m−2 at TOA (monthly mean values). The corresponding daily peak values for natural aerosol are over −10 W m−2, 6 W m−2 and −3 W m−2. Annual mean values and standard deviations (interannual variability) of anthropogenic aerosol forcing are −10 ± 3 W m−2 at the surface, 5 ± 1 W m−2 in the atmosphere and −3 ± 1 W m−2 at TOA, while the corresponding values for natural aerosol are −6 ± 2 W m−2, 3 ± 1 W m−2 and −3 ± 1 W m−2.
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Kalidindi, Sirisha, Christian H. Reick, Thomas Raddatz y Martin Claussen. "Two drastically different climate states on an Earth-like terra-planet". Earth System Dynamics 9, n.º 2 (7 de junio de 2018): 739–56. http://dx.doi.org/10.5194/esd-9-739-2018.
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Abstract. We study an Earth-like terra-planet (water-limited terrestrial planet) with an overland recycling mechanism bringing fresh water back from the high latitudes to the low latitudes. By performing model simulations for such a planet we find two drastically different climate states for the same set of boundary conditions and parameter values: a cold and wet (CW) state with dominant low-latitude precipitation and a hot and dry (HD) state with only high-latitude precipitation. We notice that for perpetual equinox conditions, both climate states are stable below a certain threshold value of background soil albedo while above the threshold only the CW state is stable. Starting from the HD state and increasing background soil albedo above the threshold causes an abrupt shift from the HD state to the CW state resulting in a sudden cooling of about 35 ∘C globally, which is of the order of the temperature difference between present day and the Snowball Earth state. When albedo starting from the CW state is reduced down to zero the terra-planet does not shift back to the HD state (no closed hysteresis). This is due to the high cloud cover in the CW state hiding the surface from solar irradiation so that surface albedo has only a minor effect on the top of the atmosphere radiation balance. Additional simulations with present-day Earth's obliquity all lead to the CW state, suggesting a similar abrupt transition from the HD state to the CW state when increasing obliquity from zero. Our study also has implications for the habitability of Earth-like terra-planets. At the inner edge of the habitable zone, the higher cloud cover in the CW state cools the planet and may prevent the onset of a runaway greenhouse state. At the outer edge, the resupply of water at low latitudes stabilizes the greenhouse effect and keeps the planet in the HD state and may prevent water from getting trapped at high latitudes in frozen form. Overall, the existence of bistability in the presence of an overland recycling mechanism hints at the possibility of a wider habitable zone for Earth-like terra-planets at low obliquities.
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Guo, Fuxiang, Xiaobing Zheng, Yanna Zhang, Wei Wei, Zejie Zhang, Quan Zhang y Xin Li. "A Wide-Angle Hyperspectral Top-of-Atmosphere Reflectance Model for the Libyan Desert". Remote Sensing 16, n.º 8 (16 de abril de 2024): 1406. http://dx.doi.org/10.3390/rs16081406.
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Reference targets with stability, uniformity, and known reflectance on the Earth’s surface, such as deserts, can be used for the absolute radiometric calibration of satellite sensors. A wide-angle hyperspectral reflectance model at the top of atmosphere (TOA) over such a reference target will expand the applicability of on-orbit calibration to different spectral bands and angles. To achieve the long-term, continuous, and high-precision absolute radiometric calibration of remote sensors, a wide-angle hyperspectral TOA reflectance model of the Libyan Desert was constructed based on spectral reflectance data, satellite overpass parameters, and atmospheric parameters from the Terra/Aqua and Earth Observation-1 (EO-1) satellites between 2003 and 2012. By means of angle fitting, viewing angle grouping, and spectral extension, the model is applicable for absolute radiometric calibration of the visible to short-wave infrared (SWIR) bands for sensors within viewing zenith angles of 65 degrees. To validate the accuracy and precision of the model, a total of 3120 long-term validations of model accuracy and 949 cross-validations with the Landsat 8 Operational Land Imager (OLI) and Suomi National Polar-Orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) satellite sensors between 2013 and 2020 were conducted. The results show that the TOA reflectance calculated by the model had a standard deviation (SD) of relative differences below 1.9% and a root-mean-square error (RMSE) below 0.8% when compared with observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat 8 OLI. The SD of the relative differences and the RMSE were within 2.7% when predicting VIIRS data.