Articles de revues : « Atmospheric databases »

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Guo, Yuhang, Xiaoying Li, Tianhai Cheng, Shenshen Li, Xinyuan Zhang, Wenjing Lu et Weifang Fang. « Construction of the Global Reference Atmospheric Profile Database ». Remote Sensing 15, n^o 12 (8 juin 2023) : 3006. http://dx.doi.org/10.3390/rs15123006.

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Atmospheric profiles are important input parameters for atmospheric radiative transfer models and atmospheric parameter inversions. The construction of regionally representative reference atmospheric profiles can provide basic data for global atmospheric and environmental research. Most reference atmospheric profile databases commonly used lag behind in updating frequency. These databases usually have limited spatial and temporal resolution and differ greatly from the real atmospheric state. To present the real atmospheric state, this article constructs the Global Reference Atmospheric Profile Database (GRAP) based on ACE-FTS satellite products of 2021 and 2022, AIRS satellite products and ERA5 reanalysis data of 2022 u6sing a random forest regression model and a hierarchical mean algorithm. The radiance spectrum of FY-3E HIRAS-II using different profile databases was simulated and compared with the measured spectrum. The results show that GRAP spectral simulations fit better with the measured HIRAS-II spectrum. Comparing the CO2, CH4, O3 and N2O profiles of GRAP, AFGL, MIPAS, RTTOV and NDACC ground station profiles in equatorial, mid-latitude summer and polar winter, the results show that GRAP has high spatial and temporal resolution and better fits the current real atmospheric state. Comparing the temperature profiles of eight regions in China, the results illustrate that GRAP is a better representation of the state of the atmosphere in the Chinese region. GRAP can provide fundamental atmospheric data for radiative transfer studies and atmospheric parameter inversions.

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Vicent, Jorge, Jochem Verrelst, Neus Sabater, Luis Alonso, Juan Pablo Rivera-Caicedo, Luca Martino, Jordi Muñoz-Marí et José Moreno. « Comparative analysis of atmospheric radiative transfer models using the Atmospheric Look-up table Generator (ALG) toolbox (version 2.0) ». Geoscientific Model Development 13, n^o 4 (20 avril 2020) : 1945–57. http://dx.doi.org/10.5194/gmd-13-1945-2020.

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Abstract. Atmospheric radiative transfer models (RTMs) are software tools that help researchers in understanding the radiative processes occurring in the Earth's atmosphere. Given their importance in remote sensing applications, the intercomparison of atmospheric RTMs is therefore one of the main tasks used to evaluate model performance and identify the characteristics that differ between models. This can be a tedious tasks that requires good knowledge of the model inputs/outputs and the generation of large databases of consistent simulations. With the evolution of these software tools, their increase in complexity bears implications for their use in practical applications and model intercomparison. Existing RTM-specific graphical user interfaces are not optimized for performing intercomparison studies of a wide variety of atmospheric RTMs. In this paper, we present the Atmospheric Look-up table Generator (ALG) version 2.0, a new software tool that facilitates generating large databases for a variety of atmospheric RTMs. ALG facilitates consistent and intuitive user interaction to enable the running of model executions and storing of RTM data for any spectral configuration in the optical domain. We demonstrate the utility of ALG in performing intercomparison studies of radiance simulations from broadly used atmospheric RTMs (6SV, MODTRAN, and libRadtran) through global sensitivity analysis. We expect that providing ALG to the research community will facilitate the usage of atmospheric RTMs to a wide range of applications in Earth observation.

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Maycock, Amanda C., Katja Matthes, Susann Tegtmeier, Hauke Schmidt, Rémi Thiéblemont, Lon Hood, Hideharu Akiyoshi et al. « The representation of solar cycle signals in stratospheric ozone – Part 2 : Analysis of global models ». Atmospheric Chemistry and Physics 18, n^o 15 (13 août 2018) : 11323–43. http://dx.doi.org/10.5194/acp-18-11323-2018.

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Abstract. The impact of changes in incoming solar irradiance on stratospheric ozone abundances should be included in climate simulations to aid in capturing the atmospheric response to solar cycle variability. This study presents the first systematic comparison of the representation of the 11-year solar cycle ozone response (SOR) in chemistry–climate models (CCMs) and in pre-calculated ozone databases specified in climate models that do not include chemistry, with a special focus on comparing the recommended protocols for the Coupled Model Intercomparison Project Phase 5 and Phase 6 (CMIP5 and CMIP6). We analyse the SOR in eight CCMs from the Chemistry–Climate Model Initiative (CCMI-1) and compare these with results from three ozone databases for climate models: the Bodeker Scientific ozone database, the SPARC/Atmospheric Chemistry and Climate (AC&C) ozone database for CMIP5 and the SPARC/CCMI ozone database for CMIP6. The peak amplitude of the annual mean SOR in the tropical upper stratosphere (1–5 hPa) decreases by more than a factor of 2, from around 5 to 2 %, between the CMIP5 and CMIP6 ozone databases. This substantial decrease can be traced to the CMIP5 ozone database being constructed from a regression model fit to satellite and ozonesonde measurements, while the CMIP6 database is constructed from CCM simulations. The SOR in the CMIP6 ozone database therefore implicitly resembles the SOR in the CCMI-1 models. The structure in latitude of the SOR in the CMIP6 ozone database and CCMI-1 models is considerably smoother than in the CMIP5 database, which shows unrealistic sharp gradients in the SOR across the middle latitudes owing to the paucity of long-term ozone measurements in polar regions. The SORs in the CMIP6 ozone database and the CCMI-1 models show a seasonal dependence with enhanced meridional gradients at mid- to high latitudes in the winter hemisphere. The CMIP5 ozone database does not account for seasonal variations in the SOR, which is unrealistic. Sensitivity experiments with a global atmospheric model without chemistry (ECHAM6.3) are performed to assess the atmospheric impacts of changes in the representation of the SOR and solar spectral irradiance (SSI) forcing between CMIP5 and CMIP6. The larger amplitude of the SOR in the CMIP5 ozone database compared to CMIP6 causes a likely overestimation of the modelled tropical stratospheric temperature response between 11-year solar cycle minimum and maximum by up to 0.55 K, or around 80 % of the total amplitude. This effect is substantially larger than the change in temperature response due to differences in SSI forcing between CMIP5 and CMIP6. The results emphasize the importance of adequately representing the SOR in global models to capture the impact of the 11-year solar cycle on the atmosphere. Since a number of limitations in the representation of the SOR in the CMIP5 ozone database have been identified, we recommend that CMIP6 models without chemistry use the CMIP6 ozone database and the CMIP6 SSI dataset to better capture the climate impacts of solar variability. The SOR coefficients from the CMIP6 ozone database are published with this paper.

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Malina, Edward, Ben Veihelmann, Matthias Buschmann, Nicholas M. Deutscher, Dietrich G. Feist et Isamu Morino. « On the consistency of methane retrievals using the Total Carbon Column Observing Network (TCCON) and multiple spectroscopic databases ». Atmospheric Measurement Techniques 15, n^o 8 (20 avril 2022) : 2377–406. http://dx.doi.org/10.5194/amt-15-2377-2022.

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Abstract. The next and current generations of methane-retrieving satellite instruments are reliant on the Total Carbon Column Observing Network (TCCON) for validation. Understanding the biases inherent in TCCON and satellite methane retrievals is as important now as when TCCON started in 2004. In this study we highlight possible biases between different methane products by assessing the retrievals of the main methane isotopologue 12CH4. Using the TCCON GGG2014 retrieval environment, retrievals are performed using five separate spectroscopic databases from four separate TCCON sites (namely, Ascension Island, Ny-Ålesund, Darwin and Tsukuba) over the course of a year. The spectroscopic databases include those native to TCCON, GGG2014 and GGG2020; the high-resolution transmission molecular absorption database 2016 (HITRAN2016); the Gestion et Etude des Informations Spectroscopiques Atmosphériques 2020 (GEISA2020) database; and the ESA Scientific Exploitation of Operational Missions – Improved Atmospheric Spectroscopy Databases (SEOM-IAS). We assess the biases in retrieving methane using the standard TCCON windows and the methane window used by the Sentinel-5 Precursor (S5P) TROPOspheric Ozone Monitoring Instrument (TROPOMI) for each of the different spectroscopic databases. By assessing the retrieved 12CH4 values from individual windows against the standard TCCON retrievals, we find bias values of between 0.05 and 2.5 times the retrieval noise limit. These values vary depending on the window and TCCON site, with Ascension Island showing the lowest biases (typically <0.5) and Ny-Ålesund or Tsukuba showing the largest. For the spectroscopic databases, GEISA2020 shows the largest biases, often greater than 1.5 across the TCCON sites and considered windows. The TROPOMI spectral window (4190–4340 cm−1) shows the largest biases of all the spectral windows, typically >1, for all spectroscopic databases, suggesting that further improvements in spectroscopic parameters are necessary. We further assess the sensitivity of these biases to locally changing atmospheric conditions such as the solar zenith angle (SZA), water vapour and temperature. We find evidence of significant non-linear relationships between the variation in local conditions and the retrieval biases based on regression analysis. In general, each site, database and window combination indicates different degrees of sensitivity, with GEISA2020 often showing the most sensitivity for all TCCON sites. Ny-Ålesund and Tsukuba show the most sensitivity to variations in local condition, while Ascension Island indicates limited sensitivity. Finally, we investigate the biases associated with retrieving 13CH4 from each TCCON site and spectroscopic database, through the calculation of δ13C values. We find high levels of inconsistency, in some cases >100 ‰ between databases, suggesting more work is required to refine the spectroscopic parameters of 13CH4.

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Martin, Chris J., Mohammed H. Haji, Peter M. Dew, Michael J. Pilling et Peter K. Jimack. « Semantically enhanced provenance capture for chamber model development with a master chemical mechanism ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 367, n^o 1890 (16 décembre 2008) : 987–90. http://dx.doi.org/10.1098/rsta.2008.0168.

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The development and maintenance of benchmark databases within scientific communities is reliant on interactions with database users. We explore the role of semantically enhanced provenance for computational modelling processes that make use of one such database: the master chemical mechanism, a key resource within the atmospheric chemistry community.

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He, Yutong, Di Tian, Hongxia Wang, Li Yao, Miao Yu et Pengfei Chen. « A universal and multi-dimensional model for analytical data on geological samples ». Geoscientific Instrumentation, Methods and Data Systems 8, n^o 2 (30 octobre 2019) : 277–84. http://dx.doi.org/10.5194/gi-8-277-2019.

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Abstract. To promote the sharing and reutilization of geoanalytical data, various geoanalytical databases have been established over the last 30 years. Data models, which form the core of a database, are themselves the subjects of intensive studies. Data models determine the contents stored in the databases and applications of the databases. However, most geoanalytical data models have been designed for specific geological applications, which has led to strong heterogeneity between databases. It is therefore difficult for researchers to communicate and integrate geoanalytical data between databases. In particular, every time a new database is constructed, the time-consuming process of redesigning a data model significantly increases the development cycle. This study introduces a new data model that is universally applicable and highly efficient. The data model is applied to various geoanalytical methods and corresponding applications, and comprehensive analytical data contents together with associated background metadata are summarized and catalogued. Universal data attributes are then designed based on these metadata, which means that the model can be used for any geoanalytical database. Additionally, a multi-dimensional data mode is adopted, providing geological researchers with the ability to analyze geoanalytical data from six or more dimensions with high efficiency. Part of the model is implemented with the typical database system (MySQL) and comprehensive comparison experiments with existing geoanalytical data model are presented. The result unambiguously proves that the data model developed in this paper exceeds existing models in efficiency.

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Godart, A., E. Leblois, S. Anquetin et N. Freychet. « Analysis of the Relationship between Banded Orographic Convection and Atmospheric Properties Using Factorial Discriminant Analysis and Neural Networks ». Journal of Applied Meteorology and Climatology 49, n^o 4 (1 avril 2010) : 646–63. http://dx.doi.org/10.1175/2009jamc2217.1.

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Abstract The relationship between banded orographic convection and atmospheric properties is investigated for a region in the south of France where the associated rainfall events are thought to represent a significant portion of the hydrologic input. The purpose is to develop a method capable of producing an extensive database of banded orographic convection rainfall events from atmospheric sounding data for this region where insufficient rain gauge data and little or no suitable radar or satellite data are available. Two statistical methods—discriminant factorial analysis (DFA) and neural networks (NNs)—are used to determine 16 so-called elaborated nonlinear variables that best identify rainfall events related to banded orographic convection from atmospheric soundings. The approach takes rainfall information into account indirectly because it “learns” from the results of a previous study that explored meteorological and available rainfall databases, even if incomplete. The new variables include wind shear, low-level moisture fluxes, and gradients of the potential temperature in the lower layers of the atmosphere, and they were used to create an extensive database of banded orographic convection events from the archive of atmospheric soundings. Results of numerical simulations using the nonhydrostatic mesoscale (Méso-NH) meteorological model validate this approach and offer interesting perspectives for the understanding of the physical processes associated with banded orographic convection. DFA proves to be useful to determine the most discriminant factors with a physical meaning. Neural networks provide better results, but they do not allow for physical interpretation. The best solution is therefore to use the two methods together.

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Goldman, A., M. T. Coffey, J. W. Hannigan, W. G. Mankin, K. V. Chance et C. P. Rinsland. « HBr and HI line parameters update for atmospheric spectroscopy databases ». Journal of Quantitative Spectroscopy and Radiative Transfer 82, n^o 1-4 (novembre 2003) : 313–17. http://dx.doi.org/10.1016/s0022-4073(03)00160-2.

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Chevallier, F., A. Chédin, F. Cheruy et J. J. Morcrette. « TIGR-like atmospheric-profile databases for accurate radiative-flux computation ». Quarterly Journal of the Royal Meteorological Society 126, n^o 563 (janvier 2000) : 777–85. http://dx.doi.org/10.1002/qj.49712656319.

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Chilingarian, Ashot. « Thunderstorm Ground Enhancements Measured on Aragats and Progress of High-Energy Physics in the Atmosphere ». Atmosphere 14, n^o 2 (2 février 2023) : 300. http://dx.doi.org/10.3390/atmos14020300.

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High-energy physics in the atmosphere (HEPA) has undergone an intense reformation in the last decade. Correlated measurements of particle fluxes modulated by strong atmospheric electric fields, simultaneous measurements of the disturbances of the near-surface electric fields and lightning location, and registration of various meteorological parameters on the Earth have led to a better understanding of the complex processes in the terrestrial atmosphere. The cooperation of cosmic rays and atmospheric physics has led to the development of models for the origin of particle bursts recorded on the Earth’s surface, estimation of vertical and horizontal profiles of electric fields in the lower atmosphere, recovery of electron and gamma ray energy spectra, the muon deceleration effect, etc. The main goal of this review is to demonstrate how the measurements performed at the Aragats cosmic ray observatory led to new results in atmospheric physics. We monitored particle fluxes around the clock using synchronized networks of advanced sensors that recorded and stored multidimensional data in databases with open, fast, and reliable access. Visualization and statistical analysis of particle data from hundreds of measurement channels disclosed the structure and strength of the atmospheric electric fields and explained observed particle bursts. Consequent solving of direct and inverse problems of cosmic rays revealed the modulation effects that the atmospheric electric field has on cosmic ray fluxes.

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Abrams, Elliot. « Implementation and Refinement of Digital Forecasting Databases ». Bulletin of the American Meteorological Society 85, n^o 11 (novembre 2004) : 1667–72. http://dx.doi.org/10.1175/bams-85-11-1667.

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Lu, Yinghui, Zhiyuan Jiang, Kultegin Aydin, Johannes Verlinde, Eugene E. Clothiaux et Giovanni Botta. « A polarimetric scattering database for non-spherical ice particles at microwave wavelengths ». Atmospheric Measurement Techniques 9, n^o 10 (19 octobre 2016) : 5119–34. http://dx.doi.org/10.5194/amt-9-5119-2016.

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Abstract. The atmospheric science community has entered a period in which electromagnetic scattering properties at microwave frequencies of realistically constructed ice particles are necessary for making progress on a number of fronts. One front includes retrieval of ice-particle properties and signatures from ground-based, airborne, and satellite-based radar and radiometer observations. Another front is evaluation of model microphysics by application of forward operators to their outputs and comparison to observations during case study periods. Yet a third front is data assimilation, where again forward operators are applied to databases of ice-particle scattering properties and the results compared to observations, with their differences leading to corrections of the model state. Over the past decade investigators have developed databases of ice-particle scattering properties at microwave frequencies and made them openly available. Motivated by and complementing these earlier efforts, a database containing polarimetric single-scattering properties of various types of ice particles at millimeter to centimeter wavelengths is presented. While the database presented here contains only single-scattering properties of ice particles in a fixed orientation, ice-particle scattering properties are computed for many different directions of the radiation incident on them. These results are useful for understanding the dependence of ice-particle scattering properties on ice-particle orientation with respect to the incident radiation. For ice particles that are small compared to the wavelength, the number of incident directions of the radiation is sufficient to compute reasonable estimates of their (randomly) orientation-averaged scattering properties. This database is complementary to earlier ones in that it contains complete (polarimetric) scattering property information for each ice particle – 44 plates, 30 columns, 405 branched planar crystals, 660 aggregates, and 640 conical graupel – and direction of incident radiation but is limited to four frequencies (X-, Ku-, Ka-, and W-bands), does not include temperature dependencies of the single-scattering properties, and does not include scattering properties averaged over randomly oriented ice particles. Rules for constructing the morphologies of ice particles from one database to the next often differ; consequently, analyses that incorporate all of the different databases will contain the most variability, while illuminating important differences between them. Publication of this database is in support of future analyses of this nature and comes with the hope that doing so helps contribute to the development of a database standard for ice-particle scattering properties, like the NetCDF (Network Common Data Form) CF (Climate and Forecast) or NetCDF CF/Radial metadata conventions.

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Tellier, Yoann, Cyril Crevoisier, Raymond Armante, Jean-Louis Dufresne et Nicolas Meilhac. « Computation of longwave radiative flux and vertical heating rate with 4A-Flux v1.0 as an integral part of the radiative transfer code 4A/OP v1.5 ». Geoscientific Model Development 15, n^o 13 (7 juillet 2022) : 5211–31. http://dx.doi.org/10.5194/gmd-15-5211-2022.

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Abstract. Based on advanced spectroscopic databases, line-by-line and layer-by-layer radiative transfer codes numerically solve the radiative transfer equation with very high accuracy. Taking advantage of its pre-calculated optical depth lookup table, the fast and accurate radiative transfer model Automatized Atmospheric Absorption Atlas OPerational (4A/OP) calculates the transmission and radiance spectra for a user-defined layered atmospheric model. Here, we present a module called 4A-Flux, which is developed and implemented into 4A/OP in order to include the calculation of the clear-sky longwave radiative flux profiles and heating rate profiles at a very high spectral resolution. Calculations are performed under the assumption of local thermodynamic equilibrium, a plane-parallel atmosphere, and specular reflection on the surface. The computation takes advantage of pre-tabulated exponential integral functions that are used instead of a classic angular quadrature. Furthermore, the sub-layer variation of the Planck function is implemented to better represent the emission of layers with a high optical depth. Thanks to the implementation of 4A-Flux, 4A/OP models have participated in the Radiative Forcing Model Intercomparison Project (RFMIP-IRF) along with other state-of-the-art radiative transfer models. 4A/OP hemispheric flux profiles are compared to other models over the 1800 representative atmospheric situations of RFMIP, yielding an outgoing longwave radiation (OLR) mean difference between 4A/OP and other models of −0.148 W m−2 and a standard deviation of 0.218 W m−2, showing a good agreement between 4A/OP and other models. 4A/OP is applied to the Thermodynamic Initial Guess Retrieval (TIGR) atmospheric database to analyze the response of the OLR and vertical heating rate to several perturbations of temperature or gas concentration. This work shows that 4A/OP with 4A-Flux module can successfully be used to simulate accurate flux and heating rate profiles and provide useful sensitivity studies including sensitivities to minor trace gases such as HFC134a, HCFC22, and CFC113. We also highlight the interest for the modeling community to extend intercomparison between models to comparisons between spectroscopic databases and modeling to improve the confidence in model simulations.

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Sadovnikov, S. A. « Software system for numerical simulation of broadband laser gas analysis of the atmosphere ». Information and Control Systems, n^o 6 (18 décembre 2018) : 66–73. http://dx.doi.org/10.31799/1684-8853-2018-6-66-73.

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Introduction: Successful monitoring of environmental parameters requires the development of flexible software complexes with evolvable calculation functionality. Purpose: Developing a modular system for numerical simulation of atmospheric laser gas analysis. Results: Based on differential absorption method, a software system has been developed which provides the calculation of molecular absorption cross-sections, molecular absorption coefficients, atmospheric transmission spectra, and lidar signals. Absorption line contours are calculated using the Voigt profile. The prior information sources are HITRAN spectroscopic databases and statistical models of the distribution of temperature, pressure and gas components in the atmosphere. For modeling lidar signals, software blocks of calculating the molecular scattering coefficient and aerosol absorption/scattering coefficients were developed. For testing the applicability of various laser sources in the problems of environmental monitoring of the atmosphere, a concentration reconstruction error calculation block was developed for the atmospheric gas components, ignoring the interfering absorption of laser radiation by foreign gases. To verify the correct functioning of the software, a program block was developed for comparing the results of the modeling of atmospheric absorption and transmission spectra by using the standard SPECTRA information system. The discrepancy between the calculation of the atmospheric transmission spectra obtained using the developed system as compared to the SPECTRA results is less than 1%. Thus, a set of the presented program blocks allows you to carry out complex modeling of remote atmospheric gas analysis. Practical relevance: The software complex allows you to rapidly assess the possibilities of using a wide range of laser radiation sources for the problems of remote gas analysis.

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Hassler, B., G. E. Bodeker et M. Dameris. « Technical Note : A new global database of trace gases and aerosols from multiple sources of high vertical resolution measurements ». Atmospheric Chemistry and Physics 8, n^o 17 (10 septembre 2008) : 5403–21. http://dx.doi.org/10.5194/acp-8-5403-2008.

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Abstract. A new database of trace gases and aerosols with global coverage, derived from high vertical resolution profile measurements, has been assembled as a collection of binary data files; hereafter referred to as the "Binary DataBase of Profiles" (BDBP). Version 1.0 of the BDBP, described here, includes measurements from different satellite- (HALOE, POAM II and III, SAGE I and II) and ground-based measurement systems (ozonesondes). In addition to the primary product of ozone, secondary measurements of other trace gases, aerosol extinction, and temperature are included. All data are subjected to very strict quality control and for every measurement a percentage error on the measurement is included. To facilitate analyses, each measurement is added to 3 different instances (3 different grids) of the database where measurements are indexed by: (1) geographic latitude, longitude, altitude (in 1 km steps) and time, (2) geographic latitude, longitude, pressure (at levels ~1 km apart) and time, (3) equivalent latitude, potential temperature (8 levels from 300 K to 650 K) and time. In contrast to existing zonal mean databases, by including a wider range of measurement sources (both satellite and ozonesondes), the BDBP is sufficiently dense to permit calculation of changes in ozone by latitude, longitude and altitude. In addition, by including other trace gases such as water vapour, this database can be used for comprehensive radiative transfer calculations. By providing the original measurements rather than derived monthly means, the BDBP is applicable to a wider range of applications than databases containing only monthly mean data. Monthly mean zonal mean ozone concentrations calculated from the BDBP are compared with the database of Randel and Wu, which has been used in many earlier analyses. As opposed to that database which is generated from regression model fits, the BDBP uses the original (quality controlled) measurements with no smoothing applied in any way and as a result displays higher natural variability.

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Braga, Gustavo Bastos, Hewlley Maria Acioli Imbuzeiro, Gabrielle Ferreira Pires, Lais Rosa de Oliveira, Rodney Alves Barbosa et Katia de Fatima Vilela. « Frost Risk and Rural Insurance in Brazil ». Revista Brasileira de Meteorologia 36, n^o 4 (décembre 2021) : 703–11. http://dx.doi.org/10.1590/0102-7786360137.

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Abstract In developing countries, such as Brazil, farmers are susceptible to extreme events.The Brazilian federal government created insurance programs to mitigate extreme event effects, such as frost, called “Programa de Subvenção ao Prêmio do Seguro Rural”. Frost is an atmospheric phenomenon that causes damage to plants due to low temperatures that exceed their resistance to freezing. This paper seeks to verify the risk level of frost in Brazil, connecting this information with farmers, who contracted Rural Insurance to protect themselves from this extreme event. To reduce possible biases in calculating the frost probability, this study uses two climatological databases. The majority of the Brazilian territory has very low probabilities of this phenomenon occurring. In the databases used to verify the probability of a temperature below 2 °C, the data proposed by Sheffield paper, show that, in part of the Brazilian territory, there is less chance of frost than Xavier's data. Regardless of the database used, in Brazil, there are farmers who contract frost insurance in areas where the risks are close to zero.

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Glahn, Bob. « Comments on “Implementation and Refinement of Digital Forecasting Databases” ». Bulletin of the American Meteorological Society 86, n^o 9 (septembre 2005) : 1315–18. http://dx.doi.org/10.1175/bams-86-9-1315.

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Doebler, William, et Victor W. Sparrow. « Simulations of X-59 sonic thumps and traditional sonic booms propagated around the world for three atmospheric models ». Journal of the Acoustical Society of America 154, n^o 4_supplement (1 octobre 2023) : A106—A107. http://dx.doi.org/10.1121/10.0022946.

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Propagation simulations of sonic booms from supersonic aircraft through atmospheric data over time at fixed locations provide the opportunity to assess noise exposure statistics for different climate regions. Knowledge of climate-based differences in sonic boom noise exposure statistics is important to ensure that future civil supersonic aircraft noise certification standards are globally applicable and effective. In this presentation, simulated sonic booms from the NASA X-59 Quesst quiet supersonic aircraft and conventional supersonic aircraft were propagated through atmospheric data at 100 locations across the world using PCBoom. Noise exposure statistics are compared for propagation results from three different atmospheric databases (NOAA Global Forecast System, NOAA Climate Forecast System Version 2, and the ECMWF Reanalysis Version 5). These atmospheric models were chosen due to their global coverage, popularity, and database availability. Preliminary statistical models are fit to assess the impact of several factors including flight direction, season, ground elevation, and climate on noise exposure size and loudness. Areas with prevalence of higher noise due to their climate are identified, which could help inform future supersonic aircraft noise standards.

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Katsev, Iosif L., Alexander S. Prikhach, Eleonora P. Zege et Alexander A. Kokhanovsky. « A Robust Atmospheric Correction Procedure for Determination of Spectral Reflectance of Terrestrial Surfaces from Satellite Spectral Measurements ». Remote Sensing 13, n^o 9 (7 mai 2021) : 1831. http://dx.doi.org/10.3390/rs13091831.

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In this work, we propose simple and robust technique for the retrieval of underlying surface spectral reflectance using spaceborne observations. It can be used to process both multispectral moderate resolution satellite data and also multi-zone high spatial resolution data. The technique can work automatically for different types of land surfaces without using huge databases accumulated in advance. The new cloud discrimination and retrieval of the water vapor content in atmosphere procedures are presented. The key point of the proposed atmospheric correction technique is the suggested single-wavelength method for determining the atmospheric aerosol optical thickness without reference to a specific type of underlying surface spectrum. The retrievals of spectral reflectance for various land surfaces with developed technique, performed using computer simulation and experimental data, have demonstrated a high retrieval accuracy.

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Dickinson, Ty A., Michael B. Richman et Jason C. Furtado. « Subseasonal-to-Seasonal Extreme Precipitation Events in the Contiguous United States : Generation of a Database and Climatology ». Journal of Climate 34, n^o 18 (septembre 2021) : 7571–86. http://dx.doi.org/10.1175/jcli-d-20-0580.1.

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AbstractExtreme precipitation across multiple time scales is a natural hazard that creates a significant risk to life, with a commensurately large cost through property loss. We devise a method to create 14-day extreme-event windows that characterize precipitation events in the contiguous United States (CONUS) for the years 1915–2018. Our algorithm imposes thresholds for both total precipitation and the duration of the precipitation to identify events with sufficient length to accentuate the synoptic and longer time scale contribution to the precipitation event. Kernel density estimation is employed to create extreme-event polygons that are formed into a database spanning from 1915 through 2018. Using the developed database, we clustered events into regions using a k-means algorithm. We define the “hybrid index,” a weighted composite of silhouette score and number of clustered events, to show that the optimal number of clusters is 15. We also show that 14-day extreme precipitation events are increasing in the CONUS, specifically in the Dakotas and much of New England. The algorithm presented in this work is designed to be sufficiently flexible to be extended to any desired number of days on the subseasonal-to-seasonal (S2S) time scale (e.g., 30 days). Additional databases generated using this framework are available for download from our GitHub. Consequently, these S2S databases can be analyzed in future works to determine the climatology of S2S extreme precipitation events and be used for predictability studies for identified events.

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Paiva, L. M. S., G. C. R. Bodstein et L. C. G. Pimentel. « Influence of high-resolution surface databases on the modeling of local atmospheric circulation systems ». Geoscientific Model Development Discussions 6, n^o 4 (16 décembre 2013) : 6659–715. http://dx.doi.org/10.5194/gmdd-6-6659-2013.

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Abstract. Large-eddy simulations are performed using the Advanced Regional Prediction System (ARPS) code at horizontal grid resolutions as fine as 300 m to assess the influence of detailed and updated surface databases on the modeling of local atmospheric circulation systems of urban areas with complex terrain. Applications to air pollution and wind energy are sought. These databases are comprised of 3 arc-sec topographic data from the Shuttle Radar Topography Mission, 10 arc-sec vegetation type data from the European Space Agency (ESA) GlobCover Project, and 30 arc-sec Leaf Area Index and Fraction of Absorbed Photosynthetically Active Radiation data from the ESA GlobCarbon Project. Simulations are carried out for the Metropolitan Area of Rio de Janeiro using six one-way nested-grid domains that allow the choice of distinct parametric models and vertical resolutions associated to each grid. ARPS is initialized using the Global Forecasting System with 0.5°-resolution data from the National Center of Environmental Prediction, which is also used every 3 h as lateral boundary condition. Topographic shading is turned on and two soil layers with depths of 0.01 and 1.0 m are used to compute the soil temperature and moisture budgets in all runs. Results for two simulated runs covering the period from 6 to 7 September 2007 are compared to surface and upper-air observational data to explore the dependence of the simulations on initial and boundary conditions, topographic and land-use databases and grid resolution. Our comparisons show overall good agreement between simulated and observed data and also indicate that the low resolution of the 30 arc-sec soil database from United States Geological Survey, the soil moisture and skin temperature initial conditions assimilated from the GFS analyses and the synoptic forcing on the lateral boundaries of the finer grids may affect an adequate spatial description of the meteorological variables.

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Qiu, Xin, Irene Cheng, Fuquan Yang, Erin Horb, Leiming Zhang et Tom Harner. « Emissions databases for polycyclic aromatic compounds in the Canadian Athabasca oil sands region – development using current knowledge and evaluation with passive sampling and air dispersion modelling data ». Atmospheric Chemistry and Physics 18, n^o 5 (8 mars 2018) : 3457–67. http://dx.doi.org/10.5194/acp-18-3457-2018.

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Abstract. Two speciated and spatially resolved emissions databases for polycyclic aromatic compounds (PACs) in the Athabasca oil sands region (AOSR) were developed. The first database was derived from volatile organic compound (VOC) emissions data provided by the Cumulative Environmental Management Association (CEMA) and the second database was derived from additional data collected within the Joint Canada–Alberta Oil Sands Monitoring (JOSM) program. CALPUFF modelling results for atmospheric polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, and dibenzothiophenes (DBTs), obtained using each of the emissions databases, are presented and compared with measurements from a passive air monitoring network. The JOSM-derived emissions resulted in better model–measurement agreement in the total PAH concentrations and for most PAH species concentrations compared to results using CEMA-derived emissions. At local sites near oil sands mines, the percent error of the model compared to observations decreased from 30 % using the CEMA-derived emissions to 17 % using the JOSM-derived emissions. The improvement at local sites was likely attributed to the inclusion of updated tailings pond emissions estimated from JOSM activities. In either the CEMA-derived or JOSM-derived emissions scenario, the model underestimated PAH concentrations by a factor of 3 at remote locations. Potential reasons for the disagreement include forest fire emissions, re-emissions of previously deposited PAHs, and long-range transport not considered in the model. Alkylated PAH and DBT concentrations were also significantly underestimated. The CALPUFF model is expected to predict higher concentrations because of the limited chemistry and deposition modelling. Thus the model underestimation of PACs is likely due to gaps in the emissions database for these compounds and uncertainties in the methodology for estimating the emissions. Future work is required that focuses on improving the PAC emissions estimation and speciation methodologies and reducing the uncertainties in VOC emissions which are subsequently used in PAC emissions estimation.

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Fiorino, Steven T., Robb M. Randall, Richard J. Bartell, Adam D. Downs, Peter C. Chu et C. W. Fan. « Climate Change : Anticipated Effects on High-Energy Laser Weapon Systems in Maritime Environments ». Journal of Applied Meteorology and Climatology 50, n^o 1 (1 janvier 2011) : 153–66. http://dx.doi.org/10.1175/2010jamc2482.1.

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Abstract This study quantifies the potential impacts on ship-defense high-energy-laser (HEL) performance due to atmospheric effects in the marine boundary layer driven by recent observations and analysis of worldwide sea surface temperatures (SSTs). The atmospheric effects are defined using the worldwide probabilistic climatic database available in the High Energy Laser End-to-End Operational Simulation (HELEEOS) model, which includes an SST database for the period 1854–1997. A more recent worldwide sea surface temperature database was provided by the Naval Postgraduate School for the period 1990–2008. Mean differences and trends between the two SST databases are used to deduce possible climate change impacts on simulated maritime HEL engagements. The anticipated effects on HEL propagation performance are assessed at an operating wavelength of 1.0642 μm across the world’s oceans and mapped onto a 1° × 1° grid. The scenario evaluated is near surface and nearly horizontal over a range of 5000 m in which anticipated clear-air maritime aerosols occur. Summer and winter scenarios are considered. In addition to realistic vertical profiles of molecular and aerosol absorption and scattering, correlated optical turbulence profiles in probabilistic (percentile) format are used.

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Esposito, F., G. Grieco, G. Masiello, G. Pavese, R. Restieri, C. Serio et V. Cuomo. « Intercomparison of line-parameter spectroscopic databases using downwelling spectral radiance ». Quarterly Journal of the Royal Meteorological Society 133, S3 (6 décembre 2007) : 191–202. http://dx.doi.org/10.1002/qj.131.

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Barbré, Robert E. « Quality Control Algorithms for the Kennedy Space Center 50-MHz Doppler Radar Wind Profiler Winds Database ». Journal of Atmospheric and Oceanic Technology 29, n^o 12 (1 décembre 2012) : 1731–43. http://dx.doi.org/10.1175/jtech-d-11-00205.1.

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Abstract This paper presents the process used by the Marshall Space Flight Center Natural Environments Branch (EV44) to quality control (QC) data from the Kennedy Space Center’s 50-MHz Doppler radar wind profiler (DRWP) for use in vehicle wind loads and steering commands. The database has been built to mitigate limitations of using the currently archived databases from weather balloons. The DRWP database contains wind measurements from approximately 2.7- to 18.6-km altitude at roughly 5-min intervals for the August 1997–December 2009 period of record, and the extensive QC process was designed to remove spurious data from various forms of atmospheric and nonatmospheric artifacts. The QC process is largely based on DRWP literature, but two new algorithms have been developed to remove data contaminated by convection and excessive first-guess propagations from the median filter/first-guess algorithm. In addition to describing the automated and manual QC process in detail, this paper describes the extent of the data retained. Roughly 58% of all possible wind observations exist in the database, with approximately 100 times as many complete profile sets existing relative to the EV44 balloon databases. This increased sample of near-continuous wind profile measurements may help increase launch availability by reducing the uncertainty of wind changes during launch countdown.

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Butler, J. H., T. G. Bell, B. D. Hall, B. Quack, L. J. Carpenter et J. Williams. « Technical Note : Ensuring consistent, global measurements of very short-lived halocarbon gases in the ocean and atmosphere ». Atmospheric Chemistry and Physics 10, n^o 2 (18 janvier 2010) : 327–30. http://dx.doi.org/10.5194/acp-10-327-2010.

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Abstract. Very short-lived halocarbons are significant sources of reactive halogen in the marine boundary layer, and likely in the upper troposphere and lower stratosphere. Quantifying ambient concentrations in the surface ocean and atmosphere is essential for understanding the atmospheric impact of these trace gas fluxes. Despite the body of literature increasing substantially over recent years, calibration issues complicate the comparison of results and limit the utility of building larger-scale databases that would enable further development of the science (e.g. sea-air flux quantification, model validation, etc.). With this in mind, thirty-one scientists from both atmospheric and oceanic halocarbon communities in eight nations gathered in London in February 2008 to discuss the scientific issues and plan an international effort toward developing common calibration scales (http://tinyurl.com/c9cg58). Here, we discuss the outputs from this meeting, suggest the compounds that should be targeted initially, identify opportunities for beginning calibration and comparison efforts, and make recommendations for ways to improve the comparability of previous and future measurements.

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Mei, Linlu, Vladimir Rozanov, Alexei Rozanov et John P. Burrows. « SCIATRAN software package (V4.6) : update and further development of aerosol, clouds, surface reflectance databases and models ». Geoscientific Model Development 16, n^o 5 (14 mars 2023) : 1511–36. http://dx.doi.org/10.5194/gmd-16-1511-2023.

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Abstract. Since the initiation of development at the Institute of Environmental Physics (IUP), University of Bremen, in 1994, the radiative transfer model SCIATRAN (formerly GOMETRAN) has been continuously improved and new versions have been released (Rozanov et al., 1997, 2002, 2005, 2014, 2017). In the course of development, the SCIATRAN software package became capable of simulating radiative transfer processes through the Earth's atmosphere or coupled atmosphere–ocean system with a variety of approaches to treat the sphericity of the atmosphere (plane-parallel, pseudo-spherical, approximately spherical and full-spherical solutions) in both scalar and vector modes. Supported by a variety of built-in databases and parameterizations, these capabilities made SCIATRAN widely used for various remote-sensing applications related to the retrieval of atmospheric trace gases and characteristics of aerosols, clouds and surfaces. This paper presents an overview of the cloud, aerosol and surface (CAS) databases and models implemented in the SCIATRAN software package (V4.6) and provides some recommendations on their usage. The new implementations offer potential users a flexible interface to perform radiative transfer simulations: (1) accounting for multilayer liquid water, ice and mixed-phase clouds; (2) employing typical aerosol-type parameterizations (including vertical variability) used in the satellite and model communities as well as updated databases; (3) including various surface bidirectional reflectance distribution function (BRDF) and albedo models for land, vegetation, ocean, snow and melt ponds on sea ice. The most recent version of the radiative transfer model SCIATRAN is freely available at the website of the IUP, University of Bremen: http://www.iup.physik.uni-bremen.de/sciatran (last access: November 2022).

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Mitchell, David L., Robert P. d’Entremont et R. Paul Lawson. « Inferring Cirrus Size Distributions through Satellite Remote Sensing and Microphysical Databases ». Journal of the Atmospheric Sciences 67, n^o 4 (1 avril 2010) : 1106–25. http://dx.doi.org/10.1175/2009jas3150.1.

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Abstract Since cirrus clouds have a substantial influence on the global energy balance that depends on their microphysical properties, climate models should strive to realistically characterize the cirrus ice particle size distribution (PSD), at least in a climatological sense. To date, the airborne in situ measurements of the cirrus PSD have contained large uncertainties due to errors in measuring small ice crystals (D ≲ 60 μm). This paper presents a method to remotely estimate the concentration of the small ice crystals relative to the larger ones using the 11- and 12-μm channels aboard several satellites. By understanding the underlying physics producing the emissivity difference between these channels, this emissivity difference can be used to infer the relative concentration of small ice crystals. This is facilitated by enlisting temperature-dependent characterizations of the PSD (i.e., PSD schemes) based on in situ measurements. An average cirrus emissivity relationship between 12 and 11 μm is developed here using the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument and is used to “retrieve” the PSD based on six different PSD schemes. The PSDs from the measurement-based PSD schemes are compared with corresponding retrieved PSDs to evaluate differences in small ice crystal concentrations. The retrieved PSDs generally had lower concentrations of small ice particles, with total number concentration independent of temperature. In addition, the temperature dependence of the PSD effective diameter De and fall speed Vf for these retrieved PSD schemes exhibited less variability relative to the unmodified PSD schemes. The reduced variability in the retrieved De and Vf was attributed to the lower concentrations of small ice crystals in the retrieved PSD.

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Kummerow, Christian, Wesley Berg, Jody Thomas-Stahle et Hirohiko Masunaga. « Quantifying Global Uncertainties in a Simple Microwave Rainfall Algorithm ». Journal of Atmospheric and Oceanic Technology 23, n^o 1 (1 janvier 2006) : 23–37. http://dx.doi.org/10.1175/jtech1827.1.

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Abstract While a large number of methods exist in the literature for retrieving rainfall from passive microwave brightness temperatures, little has been written about the quantitative assessment of the expected uncertainties in these rainfall products at various time and space scales. The latter is the result of two factors: sparse validation sites over most of the world’s oceans, and algorithm sensitivities to rainfall regimes that cause inconsistencies against validation data collected at different locations. To make progress in this area, a simple probabilistic algorithm is developed. The algorithm uses an a priori database constructed from the Tropical Rainfall Measuring Mission (TRMM) radar data coupled with radiative transfer computations. Unlike efforts designed to improve rainfall products, this algorithm takes a step backward in order to focus on uncertainties. In addition to inversion uncertainties, the construction of the algorithm allows errors resulting from incorrect databases, incomplete databases, and time- and space-varying databases to be examined. These are quantified. Results show that the simple algorithm reduces errors introduced by imperfect knowledge of precipitation radar (PR) rain by a factor of 4 relative to an algorithm that is tuned to the PR rainfall. Database completeness does not introduce any additional uncertainty at the global scale, while climatologically distinct space/time domains add approximately 25% uncertainty that cannot be detected by a radiometer alone. Of this value, 20% is attributed to changes in cloud morphology and microphysics, while 5% is a result of changes in the rain/no-rain thresholds. All but 2%–3% of this variability can be accounted for by considering the implicit assumptions in the algorithm. Additional uncertainties introduced by the details of the algorithm formulation are not quantified in this study because of the need for independent measurements that are beyond the scope of this paper. A validation strategy for these errors is outlined.

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Weber, K. H., G. K. Hartmann et H. Oberländer. « Literature search on atmospheric ozone and water vapour from three different online-databases ». Physics and Chemistry of the Earth, Part A : Solid Earth and Geodesy 25, n^o 8 (janvier 2000) : 639–41. http://dx.doi.org/10.1016/s1464-1895(00)00098-3.

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Tilstra, Lieuwe G., Martin de Graaf, Victor J. H. Trees, Pavel Litvinov, Oleg Dubovik et Piet Stammes. « A directional surface reflectance climatology determined from TROPOMI observations ». Atmospheric Measurement Techniques 17, n^o 7 (17 avril 2024) : 2235–56. http://dx.doi.org/10.5194/amt-17-2235-2024.

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Abstract. In this paper, we introduce a spectral surface reflectivity climatology based on observations made by TROPOMI on board the Sentinel-5P satellite. The database contains the directionally dependent Lambertian-equivalent reflectivity (DLER) of the Earth's surface for 21 wavelength bands ranging from 328 to 2314 nm and for each calendar month. The spatial resolution of the database grid is 0.125° × 0.125°. A recently developed cloud shadow detection technique is implemented to avoid dark scenes due to cloud shadow. In the database, the anisotropy of the surface reflection is described using a third-order parameterisation of the viewing angle dependence. The viewing angle dependence of the DLER is analysed globally and for a selection of surface type regions. The dependence is found to agree with the viewing angle dependence found in the GOME-2 surface DLER database. Differences exist, related to the actual solar position. On average, the viewing angle dependence in TROPOMI DLER is weaker than for GOME-2 DLER, but still important. Validation of the new database was first performed by comparison of the non-directional TROPOMI surface LER with heritage LER databases based on GOME-1, OMI, SCIAMACHY, and GOME-2 data. Agreement was found within 0.002–0.02 in the UV-VIS (below 500 nm), up to 0.003 in the NIR (670–772 nm), and below 0.001 in the short-wave infrared (SWIR) (2314 nm). These performance numbers are dominated by the performance over ocean, but they are in most cases also representative for land surfaces. For the validation of the directional TROPOMI surface DLER, we made use of comparison with the MODIS surface bi-directional reflectance distribution function (BRDF) for a selection of surface type regions. In all cases the DLER performed significantly better than the traditional LER, and we found good agreement with the MODIS surface BRDF. The TROPOMI surface DLER database is a clear improvement on previous surface albedo databases and can be used as input not only for satellite retrievals from TROPOMI observations, but also for retrievals from observations from other polar-orbiting satellite instruments provided that their equator crossing time is close to that of TROPOMI. The algorithm that is introduced in this paper can be used for the retrieval of surface reflectivity climatologies from other polar satellite missions as well, including Ocean and Land Colour Instrument (OLCI) on the Sentinel-3 satellites, Sentinel-5, and Multi-viewing Multi-channel Multi-polarisation imager (3MI) on the MetOp-SG-A1 satellite to be launched in 2025, as well as the future CO2M mission.

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Paiva, L. M. S., G. C. R. Bodstein et L. C. G. Pimentel. « Influence of high-resolution surface databases on the modeling of local atmospheric circulation systems ». Geoscientific Model Development 7, n^o 4 (14 août 2014) : 1641–59. http://dx.doi.org/10.5194/gmd-7-1641-2014.

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Abstract. Large-eddy simulations are performed using the Advanced Regional Prediction System (ARPS) code at horizontal grid resolutions as fine as 300 m to assess the influence of detailed and updated surface databases on the modeling of local atmospheric circulation systems of urban areas with complex terrain. Applications to air pollution and wind energy are sought. These databases are comprised of 3 arc-sec topographic data from the Shuttle Radar Topography Mission, 10 arc-sec vegetation-type data from the European Space Agency (ESA) GlobCover project, and 30 arc-sec leaf area index and fraction of absorbed photosynthetically active radiation data from the ESA GlobCarbon project. Simulations are carried out for the metropolitan area of Rio de Janeiro using six one-way nested-grid domains that allow the choice of distinct parametric models and vertical resolutions associated to each grid. ARPS is initialized using the Global Forecasting System with 0.5°-resolution data from the National Center of Environmental Prediction, which is also used every 3 h as lateral boundary condition. Topographic shading is turned on and two soil layers are used to compute the soil temperature and moisture budgets in all runs. Results for two simulated runs covering three periods of time are compared to surface and upper-air observational data to explore the dependence of the simulations on initial and boundary conditions, grid resolution, topographic and land-use databases. Our comparisons show overall good agreement between simulated and observational data, mainly for the potential temperature and the wind speed fields, and clearly indicate that the use of high-resolution databases improves significantly our ability to predict the local atmospheric circulation.

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Lev, Т. D., et M. M. Таlerko. « Analysis and Modeling of Meteorological Conditions for the Transport of Radionuclides During Periods of Forest Fires and Dust Windstorms in the Chornobyl Exclusion Zone ». Nuclear Power and the Environment 24, n^o 2 (2022) : 67–85. http://dx.doi.org/10.31717/2311-8253.22.2.8.

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The simulation of meteorological conditions of the atmospheric transport of radioactive aerosols during the periods of wildland fires (2015, 2018, 2020 and 2022) and dust storm (April 16–17, 2020) in the Chornobyl Exclusion Zone was carried out using the archive of reanalysis data of the European Center for Medium-Term Weather Forecasts (ECMWF). Modeling of meteorological conditions and preparation of aerosynoptic information for the LEDI model of atmospheric transport and deposition of pollutants during periods of intense emission of radionuclides into the atmosphere was carried out using two sources of information: the results of the numerical weather forecast model WRF-ARW (USA) using the databases of the Reanalysis Project, and forecast data obtained according to the GFS global model and the ECMWF operational model, which are stored in the database of the CDS climate data repository (ERA5 Copernicus). The used WRF-ARW numerical model is adapted for the territory of Ukraine by selecting parameterization models of the main physical processes in the atmosphere in accordance with synoptic situations and the season of the year. A description of typical and extreme synoptic situations during the analyzed periods of wildland fires is given using the archive of synoptic maps of surface pressure and topography AT500 for the European territory and modern technologies of geoinformation systems. With the help of the conducted synoptic analysis of wildland fire periods, the most typical synoptic situations associated with the passage of cold fronts and the direction of north and northwest winds, which contribute mostly to the secondary radioactive contamination of environmental objects in the zone of influence of emission sources in the Chornobyl Exclusion Zone, were identified. Because of global climate changes and unpredictable human activity in the form of arsons, military actions, etc., the number of fires in forest areas, industrial and residential facilities is increasing. Open sources of numerical weather forecast data make it possible to create modern meteorological support for modeling of atmospheric transport and deposition of pollutants and assessment of secondary environmental pollution using the LEDI-WRF software complex.

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Mínguez, R., A. Espejo, A. Tomás, F. J. Méndez et I. J. Losada. « Directional Calibration of Wave Reanalysis Databases Using Instrumental Data ». Journal of Atmospheric and Oceanic Technology 28, n^o 11 (1 novembre 2011) : 1466–85. http://dx.doi.org/10.1175/jtech-d-11-00008.1.

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Abstract Wave reanalysis databases (WRDBs) offer important advantages for the statistical characterization of wave climate (continuous time series, good spatial coverage, constant time span, homogeneous forcing, and more than a 40-yr-long time series) and for this reason, they have become a powerful tool for the design of offshore and coastal structures. However, WRDBs are not quantitatively perfect and corrections using instrumental observations must be addressed before they are used; this process is called calibration. The calibration is especially relevant near the coast and in areas where the orography is complex, since in these places the inaccuracy of WRDB is evident because of the bad description of the wind fields (i.e., insufficient forcing resolution). The quantitative differences between numerical and instrumental data suggest that different corrections should be applied depending on the mean direction of the sea state. This paper proposes a calibration method based on a nonlinear regression problem, where the corresponding correction parameters vary smoothly along the possible wave directions by means of cubic splines. The correction of significant wave height is performed using instrumental data: (i) buoy records and/or (ii) satellite data. The performance of the method is illustrated considering data from different locations around Spain.

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Mínguez, R., B. G. Reguero, A. Luceño et F. J. Méndez. « Regression Models for Outlier Identification (Hurricanes and Typhoons) in Wave Hindcast Databases ». Journal of Atmospheric and Oceanic Technology 29, n^o 2 (1 février 2012) : 267–85. http://dx.doi.org/10.1175/jtech-d-11-00059.1.

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Abstract The development of numerical wave prediction models for hindcast applications allows a detailed description of wave climate in locations where long-term instrumental records are not available. Wave hindcast databases (WHDBs) have become a powerful tool for the design of offshore and coastal structures, offering important advantages for the statistical characterization of wave climate all over the globe (continuous time series, wide spatial coverage, constant time span, homogeneous forcing, and more than 60-yr-long time series). However, WHDBs present several deficiencies reported in the literature. One of these deficiencies is related to typhoons and hurricanes, which are inappropriately reproduced by numerical models. The main reasons are (i) the difficulty of specifying accurate wind fields during these events and (ii) the insufficient spatiotemporal resolution used. These difficulties make the data related to these events appear as “outliers” when compared with instrumental records. These bad data distort results from calibration and/or correction techniques. In this paper, several methods for detecting the presence of typhoons and/or hurricane data are presented, and their automatic outlier identification capabilities are analyzed and compared. All the methods are applied to a global wave hindcast database and results are compared with existing hurricane and buoy databases in the Gulf of Mexico, Caribbean Sea, and North Atlantic Ocean.

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Giles, David M., Alexander Sinyuk, Mikhail G. Sorokin, Joel S. Schafer, Alexander Smirnov, Ilya Slutsker, Thomas F. Eck et al. « Advancements in the Aerosol Robotic Network (AERONET) Version 3 database – automated near-real-time quality control algorithm with improved cloud screening for Sun photometer aerosol optical depth (AOD) measurements ». Atmospheric Measurement Techniques 12, n^o 1 (11 janvier 2019) : 169–209. http://dx.doi.org/10.5194/amt-12-169-2019.

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Abstract. The Aerosol Robotic Network (AERONET) has provided highly accurate, ground-truth measurements of the aerosol optical depth (AOD) using Cimel Electronique Sun–sky radiometers for more than 25 years. In Version 2 (V2) of the AERONET database, the near-real-time AOD was semiautomatically quality controlled utilizing mainly cloud-screening methodology, while additional AOD data contaminated by clouds or affected by instrument anomalies were removed manually before attaining quality-assured status (Level 2.0). The large growth in the number of AERONET sites over the past 25 years resulted in significant burden to the manual quality control of millions of measurements in a consistent manner. The AERONET Version 3 (V3) algorithm provides fully automatic cloud screening and instrument anomaly quality controls. All of these new algorithm updates apply to near-real-time data as well as post-field-deployment processed data, and AERONET reprocessed the database in 2018. A full algorithm redevelopment provided the opportunity to improve data inputs and corrections such as unique filter-specific temperature characterizations for all visible and near-infrared wavelengths, updated gaseous and water vapor absorption coefficients, and ancillary data sets. The Level 2.0 AOD quality-assured data set is now available within a month after post-field calibration, reducing the lag time from up to several months. Near-real-time estimated uncertainty is determined using data qualified as V3 Level 2.0 AOD and considering the difference between the AOD computed with the pre-field calibration and AOD computed with pre-field and post-field calibration. This assessment provides a near-real-time uncertainty estimate for which average differences of AOD suggest a +0.02 bias and one sigma uncertainty of 0.02, spectrally, but the bias and uncertainty can be significantly larger for specific instrument deployments. Long-term monthly averages analyzed for the entire V3 and V2 databases produced average differences (V3–V2) of +0.002 with a ±0.02 SD (standard deviation), yet monthly averages calculated using time-matched observations in both databases were analyzed to compute an average difference of −0.002 with a ±0.004 SD. The high statistical agreement in multiyear monthly averaged AOD validates the advanced automatic data quality control algorithms and suggests that migrating research to the V3 database will corroborate most V2 research conclusions and likely lead to more accurate results in some cases.

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Ermida, Sofia L., et Isabel F. Trigo. « A Comprehensive Clear-Sky Database for the Development of Land Surface Temperature Algorithms ». Remote Sensing 14, n^o 10 (11 mai 2022) : 2329. http://dx.doi.org/10.3390/rs14102329.

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Land surface temperature is linked to a wide range of surface processes. Given the increased development of earth observation systems, a large effort has been put into advancing land surface temperature retrieval algorithms from remote sensors. Due to the very limited number of reliable in situ observations matching the spatial scales of satellite observations, algorithm development relies on synthetic databases, which then constitute a crucial part of algorithm development. Here we provide a database of atmospheric profiles and respective surface conditions that can be used to train and verify algorithms for land surface temperature retrieval, including machine learning techniques. The database was built from ERA5 data resampled through a dissimilarity criterion applied to the temperature and specific humidity profiles. This criterion aims to obtain regular distributions of these variables, ensuring a good representation of all atmospheric conditions. The corresponding vertical profiles of ozone and relevant surface and vertically integrated variables are also included in the dataset. Information on the surface conditions (i.e., temperature and emissivity) was complemented with data from a wide array of satellite products, enabling a more realistic surface representation. The dataset is freely available online at Zenodo.

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Warner, J., F. Carminati, Z. Wei, W. Lahoz et J. L. Attié. « Tropospheric carbon monoxide variability from AIRS and IASI under clear and cloudy conditions ». Atmospheric Chemistry and Physics Discussions 13, n^o 6 (18 juin 2013) : 16337–66. http://dx.doi.org/10.5194/acpd-13-16337-2013.

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Abstract. We study the Carbon Monoxide (CO) variability in the last decade measured by NASA's Atmospheric InfraRed Sounder (AIRS) on the Earth Observing Systems (EOS)/Aqua satellite and Europe's Infrared Atmospheric Sounder Interferometer (IASI) on MetOp platform. The focus of this study is to analyze CO variability and short-term trends separately for background CO and new emissions based on a new statistical approach. The AIRS Level 2 (L2) retrieval algorithm, as well as the IASI products from NOAA, utilizes cloud clearing to treat cloud contaminations in the signals; and this increases the data coverage significantly to a yield of more than 50% of the total measurements (Susskind et al., 2003). We first study if the cloud clearing affects CO retrievals and the subsequent trend studies by using the collocated Moderate Resolution Imaging Spectroradiometer (MODIS) (Ackerman et al., 1998) cloud mask to identify AIRS clear sky scenes. We then separate AIRS CO data into clear and cloud-cleared scenes and into background and new emissions, respectively. Furthermore, we carry out a similar study for the IASI CO and discuss the consistency with AIRS. We validate the CO variability of the emissions developed from AIRS against other emission inventory databases (i.e., Global Fire Emissions Database – GFED3 and the MACC/CityZEN UE – MACCity) and calculate that the correlation coefficients between the AIRS CO emissions and the emission inventory databases are 0.726 for the Northern Hemisphere (NH) and 0.915 for the Southern Hemisphere (SH).

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Jahantigh, Hossein. « Investigation and analysis of the Iranian autumn rainfall thickness pattern ». Időjárás 127, n^o 3 (2023) : 267–83. http://dx.doi.org/10.28974/idojaras.2023.3.1.

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The purpose of this study was to investigate and analyze the trend of autumn precipitation thickness pattern in Iran. For this purpose, two environmental and atmospheric databases have been used. Environmental data is prepared and networked in two stages, in the first stage with the help of 1434 stations and in the second stage with the help of 1061 stations. Atmospheric data includes geopotential height data obtained from the National Center for Environmental Prediction and the National Center for Atmospheric Research (NCEP / NCAR). The spatial resolution of this data is 2.5 × 2.5 degrees. The thickness of the atmosphere, which is usually between 500 and 1000 hectopascals, is shown. This thickness is considered as the thickness of the whole atmosphere. The results of the autumn precipitation trend showed that although autumn precipitation on monthly and annual scales has experienced an increasing trend in most regions, in less than 5% of Iran, the upward trend has been significant. The most intense upward trend is observed in the form of spots in the central and northern parts of the Zagros Mountain, while the greatest decreasing trend has been observed in the form of cores along the Caspian coastal cities. The results of the autumn precipitation thickness pattern showed that the autumn precipitation thickness pattern is affected by deflection and instability due to high latitude cold and humid weather and low latitude hot and humid weather occurred in North Africa, in such a way that the Black Sea and the Mediterranean Sea provide the required moisture in high latitudes and the Red Sea and the Persian Gulf in low latitudes.

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Duda, D. P., R. Palikonda et P. Minnis. « Relating observations of contrail persistence to numerical weather analysis output ». Atmospheric Chemistry and Physics Discussions 8, n^o 5 (21 octobre 2008) : 18385–407. http://dx.doi.org/10.5194/acpd-8-18385-2008.

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Abstract. The potential for using high-resolution meteorological data from two operational numerical weather analyses (NWA) to diagnose and predict persistent contrail formation is evaluated using two independent contrail observation databases. Contrail occurrence statistics derived from surface and satellite observations between April 2004 and June 2005 are matched to the humidity, vertical velocity, wind shear and atmospheric stability derived from analyses from the Rapid Update Cycle (RUC) and the Advanced Regional Prediction System (ARPS) models. The relationships between contrail occurrence and the NWA-derived statistics are analyzed to determine under which atmospheric conditions persistent contrail formation is favored within NWAs. Humidity is the most important factor determining whether contrails are short-lived or persistent, and persistent contrails are more likely to appear when vertical velocities are positive, and more likely to spread when the atmosphere is less stable. Although artificial upper limits on upper tropospheric humidity within the NWAs prevent a direct quantitative agreement of model data with contrail formation theory, logistic regression or similar statistical methods may improve the prediction of contrail occurrence.

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Markiewicz, Maria T. « A REVIEW OF MODELS FOR THE ATMOSPHERIC DISPERSION OF HEAVY GASES. PART II. MODEL QUALITY EVALUATION ». Ecological Chemistry and Engineering S 20, n^o 4 (1 décembre 2013) : 763–82. http://dx.doi.org/10.2478/eces-2013-0053.

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Abstract This is the second paper of a two part review. In its first part mathematical models for atmospheric dispersion of heavy gases are classified and the distinguished groups of models are characterised. In this part procedures for the model quality evaluation are described and the main results of model evaluation exercises and databases with experimental data related to the subject are summarised. The quality of a model is clearly of great importance since the decisions concerning the safety of people, environment are based on model calculations. Attention is focused on activities carried out in the European Union countries and in the USA. These include the work of the groups of researchers called MEG, HGDEG, projects known under the names REDIPHEM, SMEDIS, DATABASE and the model evaluation exercise carried out by the Sigma Research Corporation.

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Harrison, Jeremy J. « New and improved infrared absorption cross sections for trichlorofluoromethane (CFC-11) ». Atmospheric Measurement Techniques 11, n^o 10 (23 octobre 2018) : 5827–36. http://dx.doi.org/10.5194/amt-11-5827-2018.

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Abstract. Trichlorofluoromethane (CFC-11), a widely used refrigerant throughout much of the twentieth century and a very potent (stratospheric) ozone-depleting substance (ODS), is now banned under the Montreal Protocol. With a long atmospheric lifetime, it will only slowly degrade in the atmosphere, so monitoring its vertical concentration profile using infrared-sounding instruments, and thereby validating stratospheric loss rates in atmospheric models, is of great importance; this in turn requires high-quality laboratory spectroscopic data. This work describes new high-resolution infrared absorption cross sections of trichlorofluoromethane/dry synthetic air over the spectral range 710–1290 cm−1, determined from spectra recorded using a high-resolution Fourier transform spectrometer (Bruker IFS 125HR) and a 26 cm pathlength cell. Spectra were recorded at resolutions between 0.01 and 0.03 cm−1 (calculated as 0.9/MOPD; MOPD: maximum optical path difference) over a range of temperatures and pressures (7.5–760 Torr and 192–293 K) appropriate for atmospheric conditions. This new cross-section dataset improves upon the one currently available in the HITRAN (HIgh-resolution TRANsmission) and GEISA (Gestion et Étude des Informations Spectroscopiques Atmosphériques) databases through an extension to the range of pressures and temperatures, improved signal-to-noise and wavenumber calibrations, the lack of channel fringing, the better consistency in integrated band intensities, and additionally the coverage of the weak combination band ν2+ν5.

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Warner, J., F. Carminati, Z. Wei, W. Lahoz et J. L. Attié. « Tropospheric carbon monoxide variability from AIRS under clear and cloudy conditions ». Atmospheric Chemistry and Physics 13, n^o 24 (20 décembre 2013) : 12469–79. http://dx.doi.org/10.5194/acp-13-12469-2013.

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Abstract. We study the carbon monoxide (CO) variability in the last decade measured by NASA's Atmospheric InfraRed Sounder (AIRS) on the Earth Observing System (EOS)/Aqua satellite. The focus of this study is to analyze CO variability and short-term trends separately for background CO and fresh CO emissions based on a new statistical approach. The AIRS Level 2 (L2) retrieval algorithm utilizes cloud clearing to treat cloud contaminations in the signals, and this increases the data coverage significantly to a yield of more than 50% of the total measurements. We first study if the cloud clearing affects CO retrievals and the subsequent trend studies by using the collocated Moderate Resolution Imaging Spectroradiometer (MODIS) cloud mask to identify AIRS clear sky scenes. We then carry out a science analysis using AIRS CO data individually for the clear and cloud-cleared scenes to identify any potential effects due to cloud clearing. We also introduce a new technique to separate background and recently emitted CO observations, which aims to constrain emissions using only satellite CO data. We validate the CO variability of the recent emissions estimated from AIRS against other emission inventory databases (i.e., Global Fire Emissions Database – GFED3 and the MACC/CityZEN UE – MACCity) and calculate that the correlation coefficients between the AIRS CO recently emitted and the emission inventory databases are 0.726 for the Northern Hemisphere (NH) and 0.915 for the Southern Hemisphere (SH). The high degree of agreement between emissions identified using only AIRS CO and independent inventory sources demonstrates the validity of this approach to separate recent emissions from the background CO using one satellite data set.

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Antonescu, Bogdan, David M. Schultz, Alois Holzer et Pieter Groenemeijer. « Tornadoes in Europe : An Underestimated Threat ». Bulletin of the American Meteorological Society 98, n^o 4 (1 avril 2017) : 713–28. http://dx.doi.org/10.1175/bams-d-16-0171.1.

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Abstract The social and economic impact of tornadoes in Europe is analyzed using tornado reports from the European Severe Weather Database between 1950 and 2015. Despite what is often assumed by the general public and even by meteorologists and researchers, tornadoes do occur in Europe and they are associated with injuries, fatalities, and damages, although their reported frequencies and intensities are lower compared with the United States. Currently, the threat of tornadoes to Europe is underestimated. Few European meteorological services have developed and maintained tornado databases and even fewer have issued tornado warnings. This article summarizes our current understanding of the tornado threat to Europe by showing the changes in tornado injuries and fatalities since the 1950s and by estimating for the first time the damages associated with European tornadoes. To increase awareness of tornadoes and their threat to Europe, we propose a strategy that includes 1) collaboration between meteorological services, researchers, and the general public toward a pan-European database; 2) development of national forecasting and warning systems and of pan-European convective outlooks; and 3) development by decision-makers and emergency managers of policies and strategies that include tornadoes.

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Romano, V., S. Pau, M. Pezzopane, E. Zuccheretti, B. Zolesi, G. De Franceschi et S. Locatelli. « The electronic Space Weather upper atmosphere (eSWua) project at INGV : advancements and state of the art ». Annales Geophysicae 26, n^o 2 (26 février 2008) : 345–51. http://dx.doi.org/10.5194/angeo-26-345-2008.

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Abstract. The eSWua project is based on measurements performed by all the instruments installed by the upper atmosphere physics group of the Istituto Nazionale di Geofisica e Vulcanologia, Italy and on all the related studies. The aim is the realization of a hardware-software system to standardize historical and real-time observations for different instruments. An interactive Web site, supported by a well organized database, can be a powerful tool for the scientific and technological community in the field of telecommunications and space weather. The most common and useful database type for our purposes is the relational one, in which data are organized in tables for petabytes data archiving and the complete flexibility in data retrieving. The project started in June 2005 and will last till August 2007. In the first phase the major effort has been focused on the design of hardware and database architecture. The first two databases related to the DPS4 digisonde and GISTM measurements are complete concerning populating, tests and output procedures. Details on the structure and Web tools concerning these two databases are presented, as well as the general description of the project and technical features.

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Lorente, Alba, Tobias Borsdorff, Andre Butz, Otto Hasekamp, Joost aan de Brugh, Andreas Schneider, Lianghai Wu et al. « Methane retrieved from TROPOMI : improvement of the data product and validation of the first 2 years of measurements ». Atmospheric Measurement Techniques 14, n^o 1 (28 janvier 2021) : 665–84. http://dx.doi.org/10.5194/amt-14-665-2021.

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Abstract. The TROPOspheric Monitoring Instrument (TROPOMI) on board the Sentinel 5 Precursor (S5-P) satellite provides methane (CH4) measurements with high accuracy and exceptional temporal and spatial resolution and sampling. TROPOMI CH4 measurements are highly valuable to constrain emissions inventories and for trend analysis, with strict requirements on the data quality. This study describes the improvements that we have implemented to retrieve CH4 from TROPOMI using the RemoTeC full-physics algorithm. The updated retrieval algorithm features a constant regularization scheme of the inversion that stabilizes the retrieval and yields less scatter in the data and includes a higher resolution surface altitude database. We have tested the impact of three state-of-the-art molecular spectroscopic databases (HITRAN 2008, HITRAN 2016 and Scientific Exploitation of Operational Missions – Improved Atmospheric Spectroscopy Databases SEOM-IAS) and found that SEOM-IAS provides the best fitting results. The most relevant update in the TROPOMI XCH4 data product is the implementation of an a posteriori correction fully independent of any reference data that is more accurate and corrects for the underestimation at low surface albedo scenes and the overestimation at high surface albedo scenes. After applying the correction, the albedo dependence is removed to a large extent in the TROPOMI versus satellite (Greenhouse gases Observing SATellite – GOSAT) and TROPOMI versus ground-based observations (Total Carbon Column Observing Network – TCCON) comparison, which is an independent verification of the correction scheme. We validate 2 years of TROPOMI CH4 data that show the good agreement of the updated TROPOMI CH4 with TCCON (−3.4 ± 5.6 ppb) and GOSAT (−10.3 ± 16.8 ppb) (mean bias and standard deviation). Low- and high-albedo scenes as well as snow-covered scenes are the most challenging for the CH4 retrieval algorithm, and although the a posteriori correction accounts for most of the bias, there is a need to further investigate the underlying cause.

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Raspollini, Piera, Enrico Arnone, Flavio Barbara, Massimo Bianchini, Bruno Carli, Simone Ceccherini, Martyn P. Chipperfield et al. « Level 2 processor and auxiliary data for ESA Version 8 final full mission analysis of MIPAS measurements on ENVISAT ». Atmospheric Measurement Techniques 15, n^o 6 (28 mars 2022) : 1871–901. http://dx.doi.org/10.5194/amt-15-1871-2022.

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Abstract. High quality long-term data sets of altitude-resolved measurements of the atmospheric composition are important because they can be used both to study the evolution of the atmosphere and as a benchmark for future missions. For the final ESA reprocessing of MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) on ENVISAT (ENViromental SATellite) data, numerous improvements were implemented in the Level 2 (L2) processor Optimised Retrieval Model (ORM) version 8.22 (V8) and its auxiliary data. The implemented changes involve all aspects of the processing chain, from the modelling of the measurements with the handling of the horizontal inhomogeneities along the line of sight to the use of the optimal estimation technique to retrieve the minor species, from a more sensitive approach to detecting the spectra affected by clouds to a refined method for identifying low quality products. Improvements in the modelling of the measurements were also obtained with an update of the used spectroscopic data and of the databases providing the a priori knowledge of the atmosphere. The HITRAN_mipas_pf4.45 spectroscopic database was finalised with new spectroscopic data verified with MIPAS measurements themselves, while recently measured cross-sections were used for the heavy molecules. The Level 2 Initial Guess (IG2) data set, containing the climatology used by the MIPAS L2 processor to generate the initial guess and interfering species profiles when the retrieved profiles from previous scans are not available, was improved taking into account the diurnal variation of the profiles defined using climatologies from both measurements and models. Horizontal gradients were generated using the ECMWF ERA-Interim data closest in time and space to the MIPAS data. Further improvements in the L2 V8 products derived from the use of the L1b V8 products, which were upgraded to reduce the instrumental temporal drift and to handle the abrupt changes in the calibration gain. The improvements introduced into the ORM V8 L2 processor and its upgraded auxiliary data, together with the use of the L1b V8 products, lead to the generation of the MIPAS L2 V8 products, which are characterised by an increased accuracy, better temporal stability and a greater number of retrieved species.

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Modica, George D., Samuel Y.-K. Yee et Joseph Venuti. « Some Effects of Soil and Vegetation Databases on Spectra of Limited-Area Mesoscale Simulations ». Monthly Weather Review 120, n^o 9 (septembre 1992) : 2067–82. http://dx.doi.org/10.1175/1520-0493(1992)120<2067:seosav>2.0.co;2.

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Dixon, P. G., D. M. Brommer, B. C. Hedquist, A. J. Kalkstein, G. B. Goodrich, J. C. Walter, C. C. Dickerson, S. J. Penny et R. S. Cerveny. « Heat Mortality Versus Cold Mortality : A Study of Conflicting Databases in the United States ». Bulletin of the American Meteorological Society 86, n^o 7 (juillet 2005) : 937–44. http://dx.doi.org/10.1175/bams-86-7-937.

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Dyachuk, V. A., M. P. Bashtannik, E. M. Kiptenko, T. V. Kozlenko et L. M. Nadtochii. « STUDY OF THE AIR POLLUTION STATE MONITORING AND DIRECTIONS FOR ITS IMPROVEMENT IN KIEV CITY ». Hydrology, hydrochemistry and hydroecology, n^o 4 (55) (2019) : 111–21. http://dx.doi.org/10.17721/2306-5680.2019.4.9.

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The state of air pollution monitoring in Kyiv city was investigated. There were discussed the relevance of observation system optimization, advantages and disadvantages of the current monitoring network for air pollution in the urban atmosphere. The united complex approach was used for justification of mentioned optimization, which was combined with emission inventories databases, meteorological air pollution potential characteristics, ratified ground-based measurements data of main pollutants, and demographic urban features. The paper discusses main meteorological parameters which drive pollutants’ dispersion. Analysis provide evidence of its huge impact for the pollution regime formation and tendency to the decline of air quality, which must be taken in consideration during optimization for atmospheric air monitoring. The process of optimization for atmospheric air monitoring takes into account the orographic urban features used mainly for the purpose of statistically valid data provision. Therefore, in small microclimatic zones the monitoring sites are located within relief bodies, which are representative for the area. The research estimates results of boundary pollutants’ content caused by middle and high stationary emission sources, defined from the methodology connected with combined IEM diffusive model. Analysis of observations confirms the accuracy of defined structure for urban pollution fields. The combine usage of modeling results and observations allows increasing of atmospheric air quality estimations and helps to optimize the network with minimal amount of necessary representative sites.

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