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Zhao, C., Y. Ding, B. Ye, S. Yao, Q. Zhao, Z. Wang y Y. Wang. "An analyses of long-term precipitation variability based on entropy over Xinjiang, northwestern China". Hydrology and Earth System Sciences Discussions 8, n.º 2 (28 de marzo de 2011): 2975–99. http://dx.doi.org/10.5194/hessd-8-2975-2011.
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Abstract. Precipitation is one of important supply of water resources in arid and semiarid region of northwestern China, plays the vital role to maintain the fragile ecosystem. The entropy method was employed to detect the spatial variability of precipitation over monthly, seasonal and annual timescales in Xinjiang. The spatial distribution of precipitation variability was significantly affected by topography, and was zonal on annual, seasonal and monthly. The non-parametric Mann-kendall test was used to analyze the change point of trend. A precipitation concentration index has been developed categorize the variability of annual precipitation. The summer variability contributed less than that of other seasons to the annual variability. There is a great difference in the contribution of the different monthly variabilities to the annual mean variability in different years. Overall, the variability of precipitation was shown increase north of Xinjiang, especially in mountainous regions where the increase was statistically (P = 0.05) significant. South of the Xinjiang, the variability increased only slightly, consistent with the distribution of precipitation.
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Xie, Tiejun, Jianping Li, Kaiqi Chen, Yazhou Zhang y Cheng Sun. "Origin of Indian Ocean multidecadal climate variability: role of the North Atlantic Oscillation". Climate Dynamics 56, n.º 9-10 (1 de febrero de 2021): 3277–94. http://dx.doi.org/10.1007/s00382-021-05643-w.
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AbstractThe multidecadal variability of Indian Ocean sea surface temperature (IOSST) has an important impact on both the regional Indian Ocean climate and the global climate. Here, we explore multidecadal variability in the annual IOSST. Observational analysis shows that the annual IOSST multidecadal variability is not only related to the Pacific Decadal Oscillation (PDO), but also to the North Atlantic Oscillation (NAO). The NAO leads by 15–20 years the detrended annual IOSST in which the PDO signal of the same period has been removed. Further analysis reveals that the NAO leads the annual IOSST multidecadal variability through its leading effect on the Atlantic Multidecadal Oscillation (AMO). The AMO affects the vertical wind anomaly in the Indian Ocean region through the Atlantic–Indian Ocean multidecadal teleconnection (AIMT), which in turn affects the net longwave radiation in the Indian Ocean region, thus driving the annual IOSST multidecadal variability. A Hasselmann model based on NAO and PDO further verify the joint influence of the NAO and PDO on the multidecadal variability of the IOSST. A PDO-based linear model and a climate model that incorporates the NAO signal are also constructed for the annual IOSST. Results show that the climate model with the NAO signal can better simulate the annual IOSST. This again verifies that the NAO is part of the annual IOSST multidecadal variability source, indicating that the annual IOSST variability may be due to the combined influences of the NAO and PDO.
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Indarto, Indarto y Askin Askin. "VARIABILITAS SPASIAL HUJAN DI WILAYAH UPT PSDA DI MALANG". Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) 6, n.º 3 (28 de marzo de 2018): 171. http://dx.doi.org/10.23960/jtep-l.v6i3.171-180.
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This study show the spatial variabilit of rainfall (monthly and annual) rainfall in the area of technical implementation unit of water resources management (UPT-PSDA) in Malang. Administrative area of UPT PSDA in Malang include Malang regency, Malang city, Batu, Blitar Regency, Tulungagung Regency, and Trenggalek Regency. Daily rainfall data from 88 pluviometers spread around the areas are used as main input. The research procedures consist of : (1) data pre-analysis; (2) the analyses using ESDA tools (Histogram, voronoi, QQ-Plot); (3) interpolation by using IDW method; (4) producing a thematic map; and (5) interpretation. Analysis using the histogram, voronoi–maps and normal QQ-plots tools illustrates more detail the spatial variability of the monthly and annual rainfall around the regions. Interpolation produces a thematic map of mean monthly-rainfall, between 100 – 400 mm/month. The spatial distribution of annual rainfall was illustrated by a thematic show the average-annual-range from 1000 – 4000 mm/year. Keywords: spatial variability, rainfall, ESDA, IDW, monthly, annual rainfall
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Valdez-Cepeda, R. D. "Variability of annual wheat yields in Mexico". Agricultural and Forest Meteorology 66, n.º 3-4 (noviembre de 1993): 187–92. http://dx.doi.org/10.1016/0168-1923(93)90070-x.
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Rohli, Robert V., Sara A. Ates, Victor H. Rivera‐Monroy, Michael J. Polito, Stephen R. Midway, Edward Castañeda‐Moya, Arthur J. Gold, Emi Uchida, Mwita M. Mangora y Makoto Suwa. "Inter‐annual hydroclimatic variability in coastal Tanzania". International Journal of Climatology 39, n.º 12 (15 de mayo de 2019): 4736–50. http://dx.doi.org/10.1002/joc.6103.
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Mäemets, Helle, Lilian Freiberg, Marina Haldna y Tõnu Möls. "Inter-annual variability of Potamogeton perfoliatus stands". Aquatic Botany 85, n.º 3 (octubre de 2006): 177–83. http://dx.doi.org/10.1016/j.aquabot.2006.03.008.
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Winder, Monika y James E. Cloern. "The annual cycles of phytoplankton biomass". Philosophical Transactions of the Royal Society B: Biological Sciences 365, n.º 1555 (12 de octubre de 2010): 3215–26. http://dx.doi.org/10.1098/rstb.2010.0125.
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Terrestrial plants are powerful climate sentinels because their annual cycles of growth, reproduction and senescence are finely tuned to the annual climate cycle having a period of one year. Consistency in the seasonal phasing of terrestrial plant activity provides a relatively low-noise background from which phenological shifts can be detected and attributed to climate change. Here, we ask whether phytoplankton biomass also fluctuates over a consistent annual cycle in lake, estuarine–coastal and ocean ecosystems and whether there is a characteristic phenology of phytoplankton as a consistent phase and amplitude of variability. We compiled 125 time series of phytoplankton biomass (chlorophyll a concentration) from temperate and subtropical zones and used wavelet analysis to extract their dominant periods of variability and the recurrence strength at those periods. Fewer than half (48%) of the series had a dominant 12-month period of variability, commonly expressed as the canonical spring-bloom pattern. About 20 per cent had a dominant six-month period of variability, commonly expressed as the spring and autumn or winter and summer blooms of temperate lakes and oceans. These annual patterns varied in recurrence strength across sites, and did not persist over the full series duration at some sites. About a third of the series had no component of variability at either the six- or 12-month period, reflecting a series of irregular pulses of biomass. These findings show that there is high variability of annual phytoplankton cycles across ecosystems, and that climate-driven annual cycles can be obscured by other drivers of population variability, including human disturbance, aperiodic weather events and strong trophic coupling between phytoplankton and their consumers. Regulation of phytoplankton biomass by multiple processes operating at multiple time scales adds complexity to the challenge of detecting climate-driven trends in aquatic ecosystems where the noise to signal ratio is high.
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Askin, Askin, Indarto Indarto, Dimas Ghufron Ash-Shiddiq y Sri Wahyuningsih. "Variabilitas Spasial Hujan Tahunan di Wilayah UPT PSDA di Pasuruan, Jawa Timur : Analisis Histogram dan Normal QQ-Plot". Rona Teknik Pertanian 11, n.º 1 (1 de abril de 2018): 35–49. http://dx.doi.org/10.17969/rtp.v11i1.9981.
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Abstrak. Penelitian ini bertujuan untuk menganalisis variabilitas spasial hujan di wilayah UPT PSDA di Pasuruan. Wilayah studi mencakup kabupaten Probolinggo, kota Probolinggo, Kabupaten Pasuruan dan Kota Pasuruan di Jawa Timur. Data hujan tahunan rerata (Hthn_rrt) dan hujan tahunan maksimal (HthnMaks) dihitung dari kumulatif data hujan harian pada 93 stasiun dan dijadikan sebagai input utama untuk analisis. Panjang periode rekaman data yang digunakan dari tahun 1980 sampai dengan 2015 (35 tahun). Tahap penelitian mencakup: (1) pra-pengolahan data, (2) analisis pendahuluan, (3) analisis menggunakan tool histogram dan voronoi map, (4) interpolasi data dan pembuatan peta tematik. Pra-pengolahan data dilakukan menggunakan excel. Analisis histogram dan QQ-Plot dilakukan untuk melihat variabilitas spasial lebih detail per sub-wilayah. Selanjutnya, metode interpolasi digunakan untuk membuat peta tematik hujan tahunan. Peta tematik menunjukkan hujan tahunan rerata (Hthn_rrt) yang terjadi di wilayah tersebut selama 35 tahun terakhir berkisar antara 1200 sd 2600 mm/tahun. Hujan tahunan maksimal yang terjadi berkisar antara 2100 sd 4500 mm/tahun. Penelitian juga menunjukkan adanya korelasi positif antara lokasi stasiun hujan (elevasi) dengan jumlah hujan tahunan yang diterima. Spatial Variability of Annual Rainfall in The Administrative Area of UPT PSDA at Pasuruan, East Java : Analysis Using Histogram and QQ-Plot Abstract. This research aims to analyze the spatial variability of annual rainfall. Daily rainfall data from 93 rain gauge in the administrative area of UPT PSDA Pasuruan were used as the main input. The average annual rainfall and the maximum annual rainfall obtained from the daily rainfall data. Histograms, and QQ-Plot were used to describe the spatial variability in each sub-regions. Next, interpolation methods is used to create a thematic map of the annual rainfall. The results shows that local spatial variability of rainfall can be visualized more detail for each sub-region by means of histogram and QQ-Plot. The thematic map showed that the distribution of average annual rainfall in the region range from 1,200 mm/year up to 2,600 mm/year. Maximum annual rainfall range between 2,100 mm/year up to 4,500 mm/year. The result also show the positif correlation between the altitude of the rain gauge and local annual rainfall received.
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MARSZ, ANDRZEJ A. y ANNA STYSZYŃSKA. "INERCJA ROCZNEGO ODPŁYWU CAŁKOWITEGO RZEK POLSKI WZGLĘDEM MIĘDZYROCZNEJ ZMIENNOŚCI PRZEBIEGU ELEMENTÓW KLIMATYCZNYCH". Badania Fizjograficzne Seria A - Geografia Fizyczna, n.º 12 (72) (15 de diciembre de 2021): 159–79. http://dx.doi.org/10.14746/bfg.2021.12.9.
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The work discusses the formation of the annual total runoff of Polish rivers as a function of changes in the annual values of climatic elements. The results of the analysis show that in the years 1966–2015, 40–50% of the runoff variance in a hydrological year was determined by the variability of climatic elements that occurred in the preceding year, and 20–30% in the same year. This indicates the occurrence of much stronger inertia in the variability of the runoff in relation to the variability of weather conditions. The main elements influencing the variability of the runoff are the annual rainfall and the annual air temperature in the preceding year, and in the same hydrological year – the variability of annual rainfall, sunshine duration and air temperature. The runoff from the area of Poland shows a strong relationship (R = 0.82) with the de Martonne climate aridity indices, the variability of which in the preceding and the current year together explains ~66% of its variance.
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Gunnarsson, Andri, Sigurdur M. Gardarsson, Finnur Pálsson, Tómas Jóhannesson y Óli G. B. Sveinsson. "Annual and inter-annual variability and trends of albedo of Icelandic glaciers". Cryosphere 15, n.º 2 (8 de febrero de 2021): 547–70. http://dx.doi.org/10.5194/tc-15-547-2021.
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Abstract. During the melt season, absorbed solar energy, modulated at the surface predominantly by albedo, is one of the main governing factors controlling surface-melt variability for glaciers in Iceland. Using MODIS satellite-derived daily surface albedo, a gap-filled temporally continuous albedo product is derived for the melt season (May to August (MJJA)) for the period 2000–2019. The albedo data are thoroughly validated against available in situ observations from 20 glacier automatic weather stations for the period 2000–2018. The results show that spatio-temporal patterns for the melt season have generally high annual and inter-annual variability for Icelandic glaciers, ranging from high fresh-snow albedo of about 85 %–90 % in spring to 5 %–10 % in the impurity-rich bare-ice area during the peak melt season. The analysis shows that the volcanic eruptions in 2010 and 2011 had significant impact on albedo and also had a residual effect in the following years. Furthermore, airborne dust, from unstable sandy surfaces close to the glaciers, is shown to enhance radiative forcing and decrease albedo. A significant positive albedo trend is observed for northern Vatnajökull while other glaciers have non-significant trends for the study period. The results indicate that the high variability in albedo for Icelandic glaciers is driven by climatology, i.e. snow metamorphosis, tephra fallout during volcanic eruptions and their residual effects in the post-eruption years, and dust loading from widespread unstable sandy surfaces outside the glaciers. This illustrates the challenges in albedo parameterization for glacier surface-melt modelling for Icelandic glaciers as albedo development is driven by various complex phenomena, which may not be correctly captured in conventional energy-balance models.
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Yang, Chengcheng, Xiao Chen, Xuhua Cheng y Bo Qiu. "Annual versus semi-annual eddy kinetic energy variability in the Celebes Sea". Journal of Oceanography 76, n.º 6 (22 de junio de 2020): 401–18. http://dx.doi.org/10.1007/s10872-020-00553-7.
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Möller, Jens, Dietmar Dommenget y Vladimir A. Semenov. "The Annual Peak in the SST Anomaly Spectrum". Journal of Climate 21, n.º 12 (15 de junio de 2008): 2810–23. http://dx.doi.org/10.1175/2007jcli2025.1.
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Abstract The manner in which monthly mean sea surface temperature anomalies (SSTAs) show enhanced variance at the annual period in the extratropics (an annual peak in the variance spectrum) is illustrated by observations and model simulations. A mechanism, related to the reemergence of winter SST anomalies, is proposed to explain the annual peak in SST spectrum. The idea is supported by the analysis of a hierarchy of models, including Intergovernmental Panel on Climate Change model simulations. The results of the model experiments further suggest that the annual peak is either weak or absent if decadal SST variability is forced by local air–sea interaction. However, if ocean subsurface temperature variability forces decadal SST variability, the annual peak is much stronger. Strong annual peaks may therefore be seen as an indication of ocean-forced decadal SST variability in the extratropics.
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Dubravin, V. F., M. V. Kapustina y Zh I. Stont. "Estimation of heat fluxes at the ocean-atmosphere interface in the south-western part of the Baltic Sea (2003—2016)". Известия Русского географического общества 151, n.º 4 (5 de septiembre de 2019): 15–26. http://dx.doi.org/10.31857/s0869-6071151415-26.
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Based hydrometeorological data of the MARNET monitoring network, with the sampling interval of 1-hour, from 2003—2016, provided by the German Oceanographic Data Centre (BSH / DOD (M41)), the contributions of the irregular daily variability, the regular daily variability, the synoptic variability, the irregular intra-annual variability, the regular seasonal variability and the interannual component in the total temporal variability of the sensible and latent heat fluxes were estimated. The intra-annual and inter-annual variability of the specific contribution of the daily component of the sensible and latent heat fluxes are computed. It is shown that the structure of time variations of the fluxes in the southern part of the Baltic Sea depends on both, the station location and the nature of the flux itself.
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Bates, Susan C. "Coupled Ocean–Atmosphere Interaction and Variability in the Tropical Atlantic Ocean with and without an Annual Cycle". Journal of Climate 21, n.º 21 (1 de noviembre de 2008): 5501–23. http://dx.doi.org/10.1175/2008jcli1983.1.
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Abstract Many previous studies point to a connection between the annual cycle and interannual variability in the tropical Atlantic Ocean. To investigate the importance of the annual cycle in the generation of tropical Atlantic variability (TAV) as well as its associated coupled feedback mechanisms, a set of controlled experiments is conducted using a global coupled ocean–atmosphere general circulation model (GCM) in which the climatological annual cycle is modified. An anomaly coupling strategy was developed to improve the model-simulated annual cycle and mean sea surface temperature (SST), which is critical to the experiments. Experiments include a control simulation in which the annual cycle is present and a fixed annual cycle simulation in which the coupled model is forced to remain in a perpetual annual mean state. Results reveal that the patterns of TAV, defined as the leading three rotated EOFs, and their relationship to coupled feedback mechanisms are present even in the absence of the annual cycle, suggesting that the generation of TAV is not dependent on the annual cycle. Each pattern of variability arises from an alteration of the easterly trade winds. Results suggest that it is the presence of these winds in the mean state that is the determining factor for the structure of the coupled ocean–atmosphere variability. Additionally, the patterns of variability persist longer in the simulation with no annual cycle. Most remarkable is the doubling of the decay phase related to the north tropical Atlantic variability, which is attributed to the persistence of the local wind–evaporation–sea surface temperature (WES) feedback mechanism. The author concludes that the annual cycle acts to cut off or interrupt conditions favorable for feedback mechanisms to operate, therefore putting a limit on the length of the event life cycle.
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GRUNSEICH, GARY y BIN WANG. "Predictability of Arctic Annual Minimum Sea Ice Patterns". Journal of Climate 29, n.º 19 (19 de septiembre de 2016): 7065–88. http://dx.doi.org/10.1175/jcli-d-16-0102.1.
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Abstract Prediction of the arctic annual sea ice minimum extent and melting patterns draws interest from numerous industries and government agencies but has been an ongoing challenge for forecasters and climate scientists using statistical and dynamical models. Using the dominant independent modes of interannual sea ice concentration (SIC) variability during September–October, a new approach combining statistical analysis with physically derived links to natural climate variability sources is used to predict each mode and the total anomaly pattern. Sea ice patterns associated with each mode are predominantly shaped by the wind-driven advective convergence, forced by circulation anomalies associated with local and remote forms of naturally occurring climate variability. The impacts of the Arctic Oscillation, beginning from the preceding winter, control the leading mode of SIC variability during the annual minimum. In the three final months of the melting period, the broad impacts of the Indian and East Asian summer monsoons produce unique SIC impacts along the arctic periphery, displayed as the second and third modes, respectively. El Niño–Southern Oscillation (ENSO) largely shapes the fourth SIC mode patterns through influencing variability early in the melting period. Using physically meaningful and statistically significant predictors, physical–empirical (P–E) models are developed for each SIC mode. Some predictors directly account for the circulation patterns driving anomalous sea ice, while the monsoon-related predictors convey early season sources of monsoonal variability, which subsequently influences the Arctic. The combined SIC predictions of the P–E models exhibit great skill in matching the observed magnitude and temporal variability along the arctic margins during the annual minimum.
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Tiessen, M. C. H., L. Fernard, T. Gerkema, J. van der Molen, P. Ruardij y H. W. van der Veer. "Numerical modelling of physical processes governing larval transport in the Southern North Sea". Ocean Science Discussions 10, n.º 5 (17 de octubre de 2013): 1765–806. http://dx.doi.org/10.5194/osd-10-1765-2013.
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Abstract. A three-dimensional hydrodynamic model (GETM) was coupled with a particle tracking routine (GITM) to study the inter-annual variability in transport paths of particles in the North Sea and English Channel. For validation, a comparison with observed drifter trajectories was made. The aim was to investigate to what extent variability in the hydrodynamic conditions alone (reflecting passive particle transport) contributed to inter-annual variability in transport of eggs and larvae. In this idealized study, no a-priori selection of spawning grounds or periods was made and no active behaviour (vertical migration) or mortality were included. Egg and larval development towards coastal nursery areas was based solely on sea water temperature, while settlement areas were defined by a threshold water depth. Results showed strong inter-annual variability in drift direction and distance, caused by a combination of wind speed and direction. Strong inter-annual variability was observed both in absolute amount of settlement in coastal areas, as well as in the relative importance of the different areas. Settlement in the western Dutch Wadden Sea not only showed inter-annual variability, but patterns were also variable within each year and revealed seasonal changes in the origin of particles.
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Bates, Susan C. "Seasonal Influences on Coupled Ocean–Atmosphere Variability in the Tropical Atlantic Ocean". Journal of Climate 23, n.º 3 (1 de febrero de 2010): 582–604. http://dx.doi.org/10.1175/2009jcli2826.1.
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Abstract Numerous studies and observational analyses point to a connection between the annual cycle and tropical Atlantic variability, specifically the influence of the seasons. Although a previous study has shown that the annual cycle is not necessary for the generation of this variability, this study demonstrates that the annual cycle provides particular conditions that modulate this variability. Particular seasons are investigated through the use of a coupled ocean–atmosphere model using anomaly coupling as the coupling strategy in order to control the mean state of the system. To isolate the influence of each season, the model is integrated in perpetuated mean states that simulate perpetual boreal spring, summer, fall, and winter seasonal mean states. These are compared to a control simulation that contains an annual cycle. Evidence is shown that the annual cycle modulates tropical Atlantic variability in the following three ways: 1) the background mean state for some seasons provides favorable conditions for the growth of particular patterns through regional air–sea feedback mechanisms, 2) mechanisms that excite the variability are seasonally dependent, and 3) the progression through the annual cycle is important for certain variabilities to be excited and grow.
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Ruzmaikin, Alexander, Hartmut H. Aumann y Jonathan H. Jiang. "Interhemispheric Variability of Earth’s Radiation". Journal of the Atmospheric Sciences 72, n.º 12 (19 de noviembre de 2015): 4615–28. http://dx.doi.org/10.1175/jas-d-15-0106.1.
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Abstract The variability of interhemispheric symmetry of Earth’s energy serves as an independent indicator of climate change. The analysis of updated data obtained from satellite measurements at the top of the atmosphere (TOA) shows that in accord with Earth’s orbital requirements the annually averaged incident solar radiation is the same in the Northern and Southern Hemispheres, the annual mean of the reflected shortwave radiation is almost north–south symmetric, and the annual mean of the outgoing longwave radiation is larger in the Northern Hemisphere by 1.4 W m−2. These mean radiations systematically differ from the mean radiations found from the numerical atmospheric models that participated in the Coupled Model Intercomparison Project phase 5 (CMIP5). The hemispheric differences of the TOA radiations vary on the annual and interannual time scales. The multidecadal variability in Earth’s north–south temperature difference reveals a similarity of trends in both hemispheres. The Atlantic meridional transport (in contrast to the Pacific meridional transport) is found to be coherent with the interhemispheric ocean heat content (OHC) difference on decadal and multidecadal time scales, indicating a critical role of the Atlantic in the interhemispheric energy balance change.
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An, Soon-Il, Yoo-Geun Ham, Jong-Seong Kug, Axel Timmermann, Jung Choi y In-Sik Kang. "The Inverse Effect of Annual-Mean State and Annual-Cycle Changes on ENSO". Journal of Climate 23, n.º 5 (1 de marzo de 2010): 1095–110. http://dx.doi.org/10.1175/2009jcli2895.1.
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Abstract The influence of the tropical Pacific annual-mean state on the annual-cycle amplitude and El Niño–Southern Oscillation (ENSO) variability is studied using the Max Planck Institute for Meteorology coupled general circulation model (CGCM) ECHAM5/Max Planck Institute Ocean Model (MPI-OM1). In a greenhouse warming experiment, an intensified annual cycle of sea surface temperature (SST) in the eastern tropical Pacific is associated with reduced ENSO variability, and vice versa. Analysis showed that the annual-mean states, especially the surface warming in the western Pacific and the thermocline deepening in the central Pacific, which is concurrent with the strong annual cycle, act to suppress ENSO amplitude and to intensify the annual-cycle amplitude, and vice versa. The western Pacific warming acts to reduce air–sea coupling strength and to shorten the ocean adjustment time scale, and the deepening of central Pacific thermocline acts to diminish vertical advection of the anomalous ocean temperature by the annual-mean upwelling. Consequently, ENSO activity is suppressed by the annual-mean states during the strong annual-cycle decades, and the opposite case associated with the weak annual-cycle decades is also true. Furthermore, the time integration of an intermediate ENSO model forced with different background state configurations, and a stability analysis of its linearized version, show that annual-mean background states during the weak (strong) annual-cycle decades are characterized by an enhanced (reduced) linear growth rate of ENSO or similarly large (small) variability of ENSO. However, the annual-cycle component of the background state changes cannot significantly modify ENSO variability. Using a hybrid coupled model, it is demonstrated that diagnosed annual-mean background states corresponding to a reduced (enhanced) annual cycle suppress (enhance) the development of the annual cycle of SST in the eastern equatorial Pacific, mainly through the weakening (intensifying) of zonal temperature advection of annual-mean SST by the annual-cycle zonal current. The above results support the idea that climate background state changes control both ENSO and the annual-cycle amplitude in opposing ways.
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Dubravin, V. F., M. V. Kapustina y Zh I. Stont. "SYNOPTIC COMPONENT OF METEOROLOGICAL ELEMENTS IN THE SOUTHERN BALTIC SEA". Journal of Oceanological Research 50, n.º 2 (29 de agosto de 2022): 34–55. http://dx.doi.org/10.29006/1564-2291.jor-2022.50(2).2.
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Based on field observations of air temperature Ta, relative humidity f (dew point temperature Td or water vapor elasticity ea), atmospheric pressure at sea level P0 and wind speed W at stations Arkona, Darss Sill and Fehmarn-Belt of the MARNET monitoring network of the German Oceanographic Datacentre for 2002–2020 with a discreteness of 1 hour, as well as on the offshore ice-resistant stationary platform of OOO LUKOIL – Kaliningradmorneft (D6) for 2004–2020 with a discreteness of 1 hour, estimates of the contributions of the short-term (consisting of irregular intradiurnal, regular daily variation, synoptic component) and long-term (consisting of irregular intra-annual, regular seasonal variation and inter-annual component) variability into the total temporal variability of the initial series of these meteorological elements. The influence of the location of the station and the nature of the meteorological element itself on the structures of the time series of meteorological elements in the southern part of the Baltic is shown. This confirms the stability of the conclusion obtained by many researchers of the temporal variability of hydrometeorological parameters for various zones and regions of the World Ocean. In this case, the relative (specific) contribution of synoptic variability for W, P0 and f is predominant for the entire initial series (47.6÷76.1%), and for Ta, Td and ea only for short-period variability (8.1÷17.7%). The intra-annual and inter-annual variability of the specific contribution of the synoptic component Ta, Td, f, ea, P0 and W are considered. Thus, the maximum contribution of the intra-annual synoptic variability is timed to September–November, and the minimum is noted in January–February. The annual range of the contribution of intra-annual synoptic variability for most stations varies from 12–38% for W and P0 to 36–38% for Ta.
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McMahon, Thomas A., Murray C. Peel, Geoffrey G. S. Pegram y Ian N. Smith. "A Simple Methodology for Estimating Mean and Variability of Annual Runoff and Reservoir Yield under Present and Future Climates". Journal of Hydrometeorology 12, n.º 1 (1 de febrero de 2011): 135–46. http://dx.doi.org/10.1175/2010jhm1288.1.
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Abstract Overlying the challenge of managing within natural hydroclimatic variability is the likely modification of runoff variability along with average runoff due to anthropogenic enhancement of greenhouse gas concentrations. In this paper analytical models are developed in which runoff mean and variability, the latter defined by the variance (or standard deviation) of annual runoff, are related to the variances and the covariance of annual precipitation and potential evapotranspiration, and the aridity index (mean annual potential evapotranspiration divided by mean annual precipitation). The method was validated using observed runoff data for 699 worldwide catchments. It was concluded that combining the Schreiber function, which relates the ratio of annual actual evapotranspiration to annual precipitation, with the analytical models provided satisfactory estimates of observed annual runoff mean and interannual variability. It was also concluded that estimates of annual runoff variability based on the simplified model of Koster and Suarez were unsatisfactory. By way of illustrating the new methodology, the approach was applied to projected annual values of precipitation from the Hadley Centre Global Environment Model version 1 (HadGEM) and it showed that considerable changes in reservoir yield are likely to occur if climate change projections of precipitation from HadGEM are realistic. Finally, further simplifications of the equations, based on the Schreiber function, are developed to estimate the mean and standard deviation of annual runoff that allow climate analysts to estimate the impact of potential climate changes on annual runoff characteristics and reservoir yield performance without having to resort to the calibration and application of a rainfall-runoff model or rely on the runoff output from general circulation models to examine such characteristics.
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HORINO, Haruhiko y Toshisuke MARUYAMA. "Spatial Variability in Annual Fluctuation of Groundwater Level". Journal of Groundwater Hydrology 32, n.º 2 (1990): 81–90. http://dx.doi.org/10.5917/jagh1987.32.81.
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S. I. HALIKATTI, M. P. POTDAR, S. M. HIREMATH y S. P. DINESHKUMAR. "Annual and seasonal rainfall variability at Dharwad, Karnataka". Journal of Agrometeorology 12, n.º 1 (1 de junio de 2010): 136–37. http://dx.doi.org/10.54386/jam.v12i1.1294.
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Huybers, Peter y William Curry. "Links between annual, Milankovitch and continuum temperature variability". Nature 441, n.º 7091 (mayo de 2006): 329–32. http://dx.doi.org/10.1038/nature04745.
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Coachman, L. K. y K. Aagaard. "Transports through Bering Strait: Annual and interannual variability". Journal of Geophysical Research 93, n.º C12 (1988): 15535. http://dx.doi.org/10.1029/jc093ic12p15535.
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Wheeler, Timothy R., Peter Q. Craufurd, Richard H. Ellis, John R. Porter y P. V. Vara Prasad. "Temperature variability and the yield of annual crops". Agriculture, Ecosystems & Environment 82, n.º 1-3 (diciembre de 2000): 159–67. http://dx.doi.org/10.1016/s0167-8809(00)00224-3.
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Pullinger, D., M. Zhang, N. Hill y T. Crutchley. "Improving uncertainty estimates: Inter-annual variability in Ireland". Journal of Physics: Conference Series 926 (noviembre de 2017): 012006. http://dx.doi.org/10.1088/1742-6596/926/1/012006.
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Delille, D., L. Mallard y C. Rosiers. "Inter-annual variability in marine coastal Antarctic bacterioplankton". Polar Biology 16, n.º 1 (enero de 1996): 19–25. http://dx.doi.org/10.1007/bf02388731.
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Pryor, S. C., R. J. Barthelmie y J. T. Schoof. "Inter-annual variability of wind indices across Europe". Wind Energy 9, n.º 1-2 (enero de 2006): 27–38. http://dx.doi.org/10.1002/we.178.
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Hunt, B. G. "Multi-annual dry episodes in Australian climatic variability". International Journal of Climatology 29, n.º 12 (17 de diciembre de 2008): 1715–30. http://dx.doi.org/10.1002/joc.1820.
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Mohanakumar, K. "Temperature variability over the tropical middle atmosphere". Annales Geophysicae 12, n.º 5 (30 de abril de 1994): 448–56. http://dx.doi.org/10.1007/s00585-994-0448-y.
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Abstract. A study on the variability of temperature in the tropical middle atmosphere over Thumba (8 32' N, 76 52' E), located at the southern part of India, has been carried out based on rocket observations for a period of 20 years, extending from 1970 to 1990. The rocketsonde-derived mean temperatures over Thumba are corrected prior to 1978 and then compared with the middle atmospheric reference model developed from satellite observations and Solar Mesosphere Explorer (SME) satellite data. Temperature variability at every 1 km interval in the 25-75 km region was analysed. The tropical stratosphere is found to be highly stable, whereas considerable variability is noted in the middle mesosphere. The effect of seasonal cycle is least in the lower stratosphere. Annual and semi-annual oscillations in temperature are the primary oscillations in the tropical middle atmosphere. Annual temperature oscillations are dominant in the mesosphere and semi-annual oscillations are strong in the stratosphere. The stratopause region is noted to be the part of the middle atmosphere least sensitive to the changes in solar activity and long-term variability.
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Braithwaite, Roger J. "Mass-balance characteristics of arctic glaciers". Annals of Glaciology 42 (2005): 225–29. http://dx.doi.org/10.3189/172756405781812899.
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AbstractA survey of available mass-balance data shows that glaciers on arctic islands, i.e. mountain glaciers and ice caps in northern Canada, Greenland, Svalbard and the Eurasian islands, share mass-balance characteristics of low annual amplitude and small interannual variability. By contrast, glaciers around the Arctic (e.g. in Alaska, Iceland, mainland Scandinavia and northern Eurasia) can have exceptionally large annual amplitude and interannual variability but otherwise share characteristics with glaciers in lower latitudes. The arctic island glaciers occur in areas with low annual precipitation and high annual temperature variability, i.e. in dry-cold or continental regions. Most glaciers surrounding the Arctic (Alaska, Iceland and Scandinavia) occur in areas with high annual precipitation and low annual temperature variability, i.e. in wet-warm or maritime regions. Earlier mass-balance modelling showed that arctic island glaciers have low sensitivity to temperature changes consistent with their low mass-balance amplitude. However, very large changes in mass balance could occur on arctic island glaciers if the sea ice surrounding the arctic islands were reduced so that the climate of the arctic islands becomes more maritime.
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P. K. SINGH, K.K. SINGH, L. S. RATHORE y A. K. BAXLA. "Climatic variability in Jhansi region of Uttar Pradesh". Journal of Agrometeorology 11, n.º 1 (1 de junio de 2009): 51–53. http://dx.doi.org/10.54386/jam.v11i1.1223.
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The daily rainfall and temperature data 1969-2000 of Jhansi were analyzed to know seasonal and annual variability. Three distinct crop growth seasons kharif (26-41 SMW), rabi (42-15 SMW) and summer (16-25 SMW) were characterized for seasonal trends. The stable rainfall period was worked out. The annual and kharif rainfall showed a decrease in rainfall in recent decade (1984-1993). Trend analysis on rainfall reflects a decrease of 0.89 and 1.12 mm per year in annual and kharif season during past 35 years whereas no such specific trend was observed for rabi and summer seasons. The temperature variability was small indicating only minor year-to-year variations. However, during recent decade, the minimum temperature showed an increase of 0.05 and 0.13 ° C per year during annual and kharif season.
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Fatichi, S., V. Yu Ivanov y E. Caporali. "Investigating Interannual Variability of Precipitation at the Global Scale: Is There a Connection with Seasonality?" Journal of Climate 25, n.º 16 (15 de agosto de 2012): 5512–23. http://dx.doi.org/10.1175/jcli-d-11-00356.1.
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Abstract Interannual variability of precipitation can directly or indirectly affect many hydrological, ecological, and biogeochemical processes that, in turn, influence climate. Despite the significant importance of the phenomenon, few studies have attempted to elucidate spatial patterns of this variability at the global scale. This study uses land gauge precipitation records of the Global Historical Climatology Network, version 2, as well as reanalysis data to provide an assessment of the spatial organization of characteristics of precipitation interannual variability. The coefficient of variation, skewness, and short- and long-range dependence of the precipitation variability are analyzed. Among the major inferences is that the coefficient of variation of annual precipitation shows a significant correlation with intra-annual seasonality. Specifically, subyearly precipitation anomalies occurring in locations with pronounced seasonality affect the total yearly amount, imposing a higher variability in the annual precipitation fluctuations. Furthermore, the study illustrates that a positive skewness of the distribution of annual precipitation is a robust property worldwide and its magnitude is related to the coefficient of variation. Additionally, annual precipitation exhibits very weak small-lag autocorrelation. Conversely, the intensity of long-memory–long-range dependence is significantly larger than zero, hinting that organized long-term variations are an important feature of the interannual variability of precipitation.
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Yin, Dongqin y Michael L. Roderick. "Inter-annual variability of the global terrestrial water cycle". Hydrology and Earth System Sciences 24, n.º 1 (24 de enero de 2020): 381–96. http://dx.doi.org/10.5194/hess-24-381-2020.
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Abstract. Variability of the terrestrial water cycle, i.e. precipitation (P), evapotranspiration (E), runoff (Q) and water storage change (ΔS) is the key to understanding hydro-climate extremes. However, a comprehensive global assessment for the partitioning of variability in P between E, Q and ΔS is still not available. In this study, we use the recently released global monthly hydrologic reanalysis product known as the Climate Data Record (CDR) to conduct an initial investigation of the inter-annual variability of the global terrestrial water cycle. We first examine global patterns in partitioning the long-term mean P‾ between the various sinks E‾, Q‾ and ΔS‾ and confirm the well-known patterns with P‾ partitioned between E‾ and Q‾ according to the aridity index. In a new analysis based on the concept of variability source and sinks we then examine how variability in the precipitation σP2 (the source) is partitioned between the three variability sinks σE2, σQ2 and σΔS2 along with the three relevant covariance terms, and how that partitioning varies with the aridity index. We find that the partitioning of inter-annual variability does not simply follow the mean state partitioning. Instead we find that σP2 is mostly partitioned between σQ2, σΔS2 and the associated covariances with limited partitioning to σE2. We also find that the magnitude of the covariance components can be large and often negative, indicating that variability in the sinks (e.g. σQ2, σΔS2) can, and regularly does, exceed variability in the source (σP2). Further investigations under extreme conditions revealed that in extremely dry environments the variance partitioning is closely related to the water storage capacity. With limited storage capacity the partitioning of σP2 is mostly to σE2, but as the storage capacity increases the partitioning of σP2 is increasingly shared between σE2, σΔS2 and the covariance between those variables. In other environments (i.e. extremely wet and semi-arid–semi-humid) the variance partitioning proved to be extremely complex and a synthesis has not been developed. We anticipate that a major scientific effort will be needed to develop a synthesis of hydrologic variability.
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Boretti, Alberto y Stefania Castelletto. "Low-Frequency Wind Energy Variability in the Continental Contiguous United States". Energies 13, n.º 1 (27 de diciembre de 2019): 144. http://dx.doi.org/10.3390/en13010144.
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Wind energy is characterized by exceptionally large power fluctuations at the single energy facility level, that remain significant also considering the average of the many different energy facilities connected to the same grid. A high-frequency statistic, 1 min or less sampling time, is needed to understand this variability and design the energy storage facilities needed to replace the combustion fuel power plants now used to stabilize a grid. While high-frequency data are unavailable for the United States, low-frequency data, collected monthly, allow assessing the month-to-month and year-to-year variability, and define a low-frequency variability “performance”. The manuscript analyzes the output of the onshore wind energy facilities of capacity more than 250 MW in the continental contiguous United States. The differences between wind energy facilities within the same macro-region, also in about the same location, are shown, for both the annual average capacity factor and the low-frequency variability parameters. Wind energy facilities with larger annual average capacity factors have reduced variability parameters, both seasonal and inter-annual, thus performing better. The facilities with a larger annual average capacity factor also feature smaller variations in between their monthly and annual outputs.
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Goebbert, Kevin H. y Lance M. Leslie. "Interannual Variability of Northwest Australian Tropical Cyclones". Journal of Climate 23, n.º 17 (1 de septiembre de 2010): 4538–55. http://dx.doi.org/10.1175/2010jcli3362.1.
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Abstract Tropical cyclone (TC) activity over the southeast Indian Ocean has been studied far less than other TC basins, such as the North Atlantic and northwest Pacific. The authors examine the interannual TC variability of the northwest Australian (NWAUS) subbasin (0°–35°S, 105°–135°E), using an Australian TC dataset for the 39-yr period of 1970–2008. Thirteen TC metrics are assessed, with emphasis on annual TC frequencies and total TC days. Major findings are that for the NWAUS subbasin, there are annual means of 5.6 TCs and 42.4 TC days, with corresponding small standard deviations of 2.3 storms and 20.0 days. For intense TCs (WMO category 3 and higher), the annual mean TC frequency is 3.0, with a standard deviation of 1.6, and the annual average intense TC days is 7.6 days, with a standard deviation of 4.5 days. There are no significant linear trends in either mean annual TC frequencies or TC days. Notably, all 13 variability metrics show no trends over the 39-yr period and are less dependent upon standard El Niño–Southern Oscillation (ENSO) variables than many other TC basins, including the rest of the Australian region basin. The largest correlations with TC frequency were geopotential heights for June–August at 925 hPa over the South Atlantic Ocean (r = −0.65) and for April–June at 700 hPa over North America (−0.64). For TC days the largest correlations are geopotential heights for July–September at 1000 hPa over the South Atlantic Ocean (−0.7) and for April–June at 850 hPa over North America (−0.58). Last, wavelet analyses of annual TC frequencies and TC days reveal periodicities at ENSO and decadal time scales. However, the TC dataset is too short for conclusive evidence of multidecadal periodicities. Given the large correlations revealed by this study, developing and testing of a multivariate seasonal TC prediction scheme has commenced, with lead times up to 6 months.
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Kashino, Yuji, Akio Ishida y Shigeki Hosoda. "Observed Ocean Variability in the Mindanao Dome Region". Journal of Physical Oceanography 41, n.º 2 (1 de febrero de 2011): 287–302. http://dx.doi.org/10.1175/2010jpo4329.1.
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Abstract Ocean variations at semiannual, annual, and interannual time scales in the Mindanao Dome (MD) region of the southern Philippine Sea were examined using data derived from underwater sensors on Triangle Trans-Ocean Buoy Network (TRITON) buoys at 8°N, 137°E; 5°N, 137°E; and 8°N, 130°E. Annual signal dominated above 300-m depth in the MD region. At 5°N, 137°E, saline water exceeding 35 psu was observed at 100–200-m depth from boreal winter to spring, seemingly associated with the meridional migration of the North Equatorial Countercurrent during these seasons. Thermocline ascent, probably related to the MD, was also observed from boreal winter to spring. An important mechanism of the annual variation of the MD at 5°N seems to be the annual variability of local wind, as mentioned in past studies. However, annual variability at 8°N seems to be due to Rossby waves originating west of 150°W rather than to local wind effects. Semiannual variation was also observed, with its amplitude reaching 40%–70% of the annual signal. With regard to interannual variability, ocean variation on the time scale of the El Niño–Southern Oscillation (ENSO) was seen; upper heat content (above 300-m depth) in the Mindanao Dome region decreased during the 2002–03 and 2006–07 El Niño periods and increased between those periods. Increasing upper heat content in this region after 2005 was probably associated with large negative anomalies of Ekman pumping (downwelling) that appeared from 2005 to 2006 east of 150°E and north of 5°N.
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Oksiuta, Monika. "Basic Parameters of the Thermal Regime of Rivers in the Vistula River Catchment". Miscellanea Geographica 14, n.º 1 (1 de diciembre de 2010): 185–92. http://dx.doi.org/10.2478/mgrsd-2010-0017.
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Abstract Seasonal and multi-annual variability of river water temperature has been analysed based on data from 24 gauge stations of the IMGW network. It has been characterised by means of several values of the thermal regime parameters: mean annual, semi-annual (November-April, May-October) and amplitude. The variability of water temperature in the catchment and in the stream network has been estimated. Measurement data included seven stations at the Vistula river. On the background of natural variability, rivers or their segments have been distinguished where water temperature is impacted by anthropopressure.
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Shinker, Jacqueline J. "Visualizing Spatial Heterogeneity of Western U.S. Climate Variability". Earth Interactions 14, n.º 10 (1 de octubre de 2010): 1–15. http://dx.doi.org/10.1175/2010ei323.1.
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Abstract Monthly climatologies (1971–2000 monthly averages) for stations in the western United States, obtained from the NOAA/National Climatic Data Center (NCDC), are used to illustrate the spatial variations in the annual cycle of climate. Animated map sequences of temperature and precipitation, their average, intermonthly changes, and the local timing of annual maxima or minima provide a comprehensive spatiotemporal baseline of regional climate. The animated maps illustrate three scales of variation: 1) broadscale patterns related to the annual cycle of insolation and hemispheric-scale atmospheric circulation features; 2) mesoscale patterns related to location on the continent and the influence of specific regional circulation features like those associated with the North American monsoon; and 3) smaller-scale spatial variations, related to the mediation by local physiography of the influence of large-scale circulation. Although most western U.S. stations have temperature maxima in July, a delay occurs at stations along the West Coast and interior Washington, northern Idaho, and Montana. A seesaw pattern of precipitation maxima is evident between coastal areas (winter dominated) and the interior (summer dominated). Cluster analyses of the ratio of monthly-to-annual precipitation values for each station identify regions with similar annual cycles of precipitation. Regions of high spatial heterogeneity in the timing of when precipitation occurs include the northern Rocky Mountains, Utah, Arizona, and northwestern Montana. The superimposition of these three scales of spatial variability leads to steep gradients and, in some regions, considerable spatial heterogeneity in annual precipitation. The regional patterns of precipitation heterogeneity highlight vulnerability to drought, especially in regions of the interior west that do not have a dominant precipitation month or season.
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Musie, Mulugeta, Sumit Sen y Indrajeet Chaubey. "Hydrologic Responses to Climate Variability and Human Activities in Lake Ziway Basin, Ethiopia". Water 12, n.º 1 (5 de enero de 2020): 164. http://dx.doi.org/10.3390/w12010164.
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Hydrological impacts of human activities and climate variability on Ketar and Meki watersheds of Lake Ziway basin, Ethiopia were studied using the soil and water assessment tool. Three land-use change and two climate variability scenarios were considered to analyze the separate and combined impacts on annual water balance, monthly streamflow, and spatial distributions of evapotranspiration and water yield. The evaluation showed that changes in land use resulted in an increase in annual surface runoff and water yield for Ketar watershed and an increase in annual ET for Meki. Similarly, the climate variability resulted in a decrease in annual ET, surface runoff, and water yield for Ketar watershed and a decrease in ET for Meki. Overall, climate variability has greater impacts on the monthly streamflow compared to land-use change impacts. Similarly, greater sensitivity in hydrologic response was observed for Ketar watershed compared to Meki watershed.
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Tiessen, M. C. H., L. Fernard, T. Gerkema, J. van der Molen, P. Ruardij y H. W. van der Veer. "Numerical modelling of physical processes governing larval transport in the southern North Sea". Ocean Science 10, n.º 3 (21 de mayo de 2014): 357–76. http://dx.doi.org/10.5194/os-10-357-2014.
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Abstract. A three-dimensional hydrodynamic model (GETM) was coupled with a particle tracking routine (GITM) to study the inter-annual variability in transport paths of particles in the North Sea and English Channel. For validation, a comparison with observed drifter trajectories is also presented here. This research investigated to what extent variability in the hydrodynamic conditions alone (reflecting passive particle transport) contributed to inter-annual variability in the transport of eggs and larvae. In this idealised study, no a priori selection of specific spawning grounds or periods was made and no active behaviour (vertical migration) or mortality was included. In this study, egg and larval development towards coastal nursery areas was based solely on sea water temperature, while settlement areas were defined by a threshold water depth. Results showed strong inter-annual variability in drift direction and distance, caused by a combination of wind speed and direction. Strong inter-annual variability was observed both in absolute amount of settlement in several coastal areas, and in the relative importance of the different areas. The effects of wind and temperature variability are minor for settlement along the western shores of the North Sea and in the English Channel, but have a very significant impact on settlement along the eastern shores of the North Sea. Years with strong south-westerly winds across the Dover Straight resulted in higher settlement figures along its eastern shores of the North Sea (standard deviation 37% of the mean annual settlement value). Settlement in the western Dutch Wadden Sea did not only show inter-annual variability, but patterns were also variable within each year and revealed seasonal changes in the origin of particles: during winter, stronger currents along with colder temperatures generally result in particles originating from further away.
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Cornes, Richard C., Philip D. Jones y Cheng Qian. "Twentieth-Century Trends in the Annual Cycle of Temperature across the Northern Hemisphere". Journal of Climate 30, n.º 15 (agosto de 2017): 5755–73. http://dx.doi.org/10.1175/jcli-d-16-0315.1.
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The annual cycle of surface air temperature is examined across Northern Hemisphere land areas (north of 25°N) by comparing the results from the Climatic Research Unit Time Series (CRU TS) dataset against four reanalysis datasets: two versions of the NOAA Twentieth Century Reanalysis (20CR and 20CRC) and two versions of the ECMWF Twentieth Century Reanalysis, version 2 (ERA-20C) and version 2c (ERA-20CM). The modulated annual cycle is adaptively derived from an ensemble empirical mode decomposition (EEMD) filter, and is used to define the phase and amplitude of the annual cycle. The EEMD method does not impose a simple sinusoidal shape of the annual cycle. None of the reanalysis simulations assimilates surface temperature or land-use data. However, they differ in the parameters that are included: both ERA-20C and 20CR assimilate surface pressure data; ERA-20C also includes surface wind data over the oceans; and ERA-20CM does not assimilate any of these synoptic data. It is demonstrated that synoptic variability is critical for explaining the trends and variability of the annual cycle of surface temperature across the Northern Hemisphere. The CMIP5 forcings alone are insufficient to explain the observed trends and decadal-scale variability, particularly with respect to the decline in the amplitude of the annual cycle throughout the twentieth century. The variability in the annual cycle during the latter half of the twentieth century was unusual in the context of the twentieth century, and was most likely related to large-scale atmospheric variability, although uncertainty in the results is greatest before about 1930.
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Hansen, Winslow D., Naomi B. Schwartz, A. Park Williams, Katharina Albrich, Lara M. Kueppers, Anja Rammig, Christopher P. O. Reyer, A. Carla Staver y Rupert Seidl. "Global forests are influenced by the legacies of past inter-annual temperature variability". Environmental Research: Ecology 1, n.º 1 (30 de agosto de 2022): 011001. http://dx.doi.org/10.1088/2752-664x/ac6e4a.
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Abstract Inter-annual climate variability (hereafter climate variability) is increasing in many forested regions due to climate change. This variability could have larger near-term impacts on forests than decadal shifts in mean climate, but how forests will respond remains poorly resolved, particularly at broad scales. Individual trees, and even forest communities, often have traits and ecological strategies—the legacies of exposure to past variable conditions—that confer tolerance to subsequent climate variability. However, whether local legacies also shape global forest responses is unknown. Our objective was to assess how past and current climate variability influences global forest productivity. We hypothesized that forests exposed to large climate variability in the past would better tolerate current climate variability than forests for which past climate was relatively stable. We used historical (1950–1969) and contemporary (2000–2019) temperature, precipitation, and vapor pressure deficit (VPD) and the remotely sensed enhanced vegetation index (EVI) to quantify how historical and contemporary climate variability relate to patterns of contemporary forest productivity. Consistent with our hypothesis, forests exposed to large temperature variability in the past were more tolerant of contemporary temperature variability than forests where past temperatures were less variable. Forests were 19-fold times less sensitive to contemporary temperature variability where historical inter-annual temperature variability was 0.66 °C (two standard deviations) greater than the global average historical temperature variability. We also found that larger increases in temperature variability between the two study periods often eroded the tolerance conferred by the legacy effects of historical temperature variability. However, the hypothesis was not supported in the case of precipitation and VPD variability, potentially due to physiological tradeoffs inherent in how trees cope with dry conditions. We conclude that the sensitivity of forest productivity to imminent increases in temperature variability may be partially predictable based on the legacies of past conditions.
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Okoro, Ugochukwu Kingsley. "Decadal Rainfall Trends and Variability Across Nigeria". International Journal of Environment and Climate Change 13, n.º 11 (10 de noviembre de 2023): 2654–65. http://dx.doi.org/10.9734/ijecc/2023/v13i113434.
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This work examined the decadal trends and variability of rainfall data over Nigeria from 1979 to 2021 (42 years). Observational monthly rainfall data was obtained from the Nigerian Meteorological Agency (NiMET). The data underwent statistical analysis to illustrate its spread and variability using metrics such as mean, standard deviation, and coefficient of variation, linear regression was applied to reveal the trends or changes over time, the coefficient of correlation was employed to assess the statistical relationships of rainfall across the distinct climate regions of Guinea, Savanna, and Sahel, respectively. There were varying levels of annual and seasonal rainfall across the regions, with Port Harcourt receiving the highest annual and seasonal rainfall in the Guinea region. Sokoto and Maiduguri exhibit the highest annual rainfall in the Sahel region. The decadal analysis highlights the fluctuations in rainfall anomalies, as some decades showed surplus rainfall while others displayed negative deviations, indicating the changing nature of regional rainfall patterns.
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van Dijk, Karin, Kathelijn Fischer, Johanna G. van der Bom, Eveline P. Mauser-Bunschoten, Goris Roosendaal y H. Marijke van den Berg. "Variability in Bleeding Pattern of Severe Hemophilia." Blood 104, n.º 11 (16 de noviembre de 2004): 3094. http://dx.doi.org/10.1182/blood.v104.11.3094.3094.
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Abstract Introduction The aim of this study was to describe variability in bleeding pattern in a single center cohort of severe hemophilia patients treated with prophylaxis. Methods At the Van Creveldkliniek, all patients with severe hemophilia born between 1944 and 2002 were followed from 1972 onwards. Data on bleeding characteristics and treatment were collected yearly and Pettersson scores were performed with five-year intervals. Prophylactic dose was adjusted always according to bleeding pattern. Since the number of accepted bleeds has decreased over the years, each treatment dependent indicator was described stratified for age. Age specific quartiles for the different indicators were used as arbitrary cut-off values. Results Data on prophylaxis were available for 247 patients, and a total of 2760 follow up years on prophylaxis were collected. Variability in treatment characteristics is shown in Table 1. Treatment characteristics and clinical manifestations per age group Year of birth 1985–2002 1968–1985 1944–1968 Values are means (interquartile range) n 66 87 94 Follow-up per patient (yr) 6.6 18.0 22.6 Age at first joint bleed (yr) 1.8 (0.7–3.7) - Annual clotting factor use (IU/kg/yr) 2790 (2282–3321) 1989 (1654–2350) 1458 (1119–1790) Joint bleeds per year 2.6 (1.0–3.7) 2.9 (1.3–5.1) 4.5 (2.2–9.9) Pettersson score (max 78 points) 0.0 (0.0–2.5) 15.1 (6.0–22.0) 44.8 (35.5–56.2) The variation in annual clotting factor use was used as a marker of bleeding pattern. Age at first joint bleed was inversely related to annual clotting factor use in the youngest age group. Using cut off levels of the 25th and 75th percentiles (P25 and P75) of age at first joint bleed and annual clotting factor use, 10% of patients were identified as patients with a milder bleeding pattern (i.e. age at first joint bleed above P75 and annual clotting factor use below P25) and 9.3% as patients with a more severe bleeding pattern. Using annual clotting factor use and joint bleed frequency in the middle group, 8.0% of patients were identified as patients with a milder phenotype and 10.3% as patients with a more severe bleeding pattern. In the oldest group, Pettersson scores were positively associated with annual clotting factor use. Using these parameters, 14% of the patients were identified as patients with a milder bleeding pattern. Due to the ceiling effect of the Pettersson score, these parameters could not be used to identify patients with a more severe bleeding pattern. Conclusion There is considerable variation in bleeding pattern of patients with severe hemophilia. Combinations of bleeding and treatment characteristics could be used as indicators of phenotype identifying 8 to 14% patients with a milder bleeding pattern and 9 to 10% of patients with a more severe bleeding pattern.
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Jung, Christopher, Diana Taubert y Dirk Schindler. "The temporal variability of global wind energy – Long-term trends and inter-annual variability". Energy Conversion and Management 188 (mayo de 2019): 462–72. http://dx.doi.org/10.1016/j.enconman.2019.03.072.
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Fay, P. A., J. M. Blair, M. D. Smith, J. B. Nippert, J. D. Carlisle y A. K. Knapp. "Relative effects of precipitation variability and warming on grassland ecosystem function". Biogeosciences Discussions 8, n.º 4 (13 de julio de 2011): 6859–900. http://dx.doi.org/10.5194/bgd-8-6859-2011.
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Abstract. Precipitation and temperature drive many aspects of terrestrial ecosystem function. Climate change scenarios predict increasing precipitation variability and temperature, and long term experiments are required to evaluate the ecosystem consequences of interannual climate variation, increased growing season (intra-annual) rainfall variability, and warming. We present results from an experiment applying increased growing season rainfall variability and year round warming in native perennial grassland. During ten years of study, total growing season rainfall varied 2-fold, and we found ~50–200 % interannual variability in plant growth and aboveground net primary productivity, leaf carbon assimilation (ACO2), and soil CO2 efflux (JCO2) despite only ∼40 % variation in mean volumetric soil water content (0–15 cm, Θ15). Interannual variation in soil moisture was thus amplified in most measures of ecosystem response. Differences between years in Θ15 explained the greatest portion (14–52 %) of the variation in these processes. Experimentally increased intra-annual rainfall variability doubled the amplitude of intra-annual soil moisture variation and reduced Θ15 by 15 %, causing most ecosystem processes to decrease 8–40 % in some or all years with increased rainfall variability compared to ambient rainfall timing, suggesting reduced ecosystem rainfall use efficiency. Warming treatments increased 5 cm soil temperature, particularly during spring, fall, and winter. Warming advanced canopy green up in spring, increased winter JCO2, and reduced summer JCO2 and forb ANPP, suggesting that the effects of warming differed in cooler versus warmer parts of the year. We conclude that (1) major ecosystem processes in this grassland may be substantially altered by predicted changes in interannual climate variability, intra-annual rainfall variability, and temperature, (2) interannual climate variation was a larger source of variation in ecosystem function than intra-annual rainfall variability and warming, and (3) effects of increased growing season rainfall variability and warming were small, but ecologically important. The relative effects of these climate drivers are likely to vary for different ecosystem processes and in wetter or drier ecosystems.
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Fay, P. A., J. M. Blair, M. D. Smith, J. B. Nippert, J. D. Carlisle y A. K. Knapp. "Relative effects of precipitation variability and warming on tallgrass prairie ecosystem function". Biogeosciences 8, n.º 10 (31 de octubre de 2011): 3053–68. http://dx.doi.org/10.5194/bg-8-3053-2011.
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Abstract. Precipitation and temperature drive many aspects of terrestrial ecosystem function. Climate change scenarios predict increasing precipitation variability and temperature, and long term experiments are required to evaluate the ecosystem consequences of interannual climate variation, increased growing season (intra-annual) rainfall variability, and warming. We present results from an experiment applying increased growing season rainfall variability and year round warming in native tallgrass prairie. During ten years of study, total growing season rainfall varied 2-fold, and we found ~50–200% interannual variability in plant growth and aboveground net primary productivity (ANPP), leaf carbon assimilation (ACO2), and soil CO2 efflux (JCO2) despite only ~40% variation in mean volumetric soil water content (0–15 cm, Θ15). Interannual variation in soil moisture was thus amplified in most measures of ecosystem response. Differences between years in Θ15 explained the greatest portion (14–52%) of the variation in these processes. Experimentally increased intra-annual season rainfall variability doubled the amplitude of intra-annual soil moisture variation and reduced Θ15 by 15%, causing most ecosystem processes to decrease 8–40% in some or all years with increased rainfall variability compared to ambient rainfall timing, suggesting reduced ecosystem rainfall use efficiency. Warming treatments increased soil temperature at 5 cm depth, particularly during spring, fall, and winter. Warming advanced canopy green up in spring, increased winter JCO2, and reduced summer JCO2 and forb ANPP, suggesting that the effects of warming differed in cooler versus warmer parts of the year. We conclude that (1) major ecosystem processes in this grassland may be substantially altered by predicted changes in interannual climate variability, intra-annual rainfall variability, and temperature, (2) interannual climate variation was a larger source of variation in ecosystem function than intra-annual rainfall variability and warming, and (3) effects of increased growing season rainfall variability and warming were small, but ecologically important. The relative effects of these climate drivers are likely to vary for different ecosystem processes and in wetter or drier ecosystems.
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Arfan, M., A. H. Makhdum y G. Nabi. "ASSESSMENT OF TEMPORAL FLOW VARIABILITY OF THE KABUL RIVER". Journal of Mountain Area Research 2 (7 de agosto de 2017): 1. http://dx.doi.org/10.53874/jmar.v2i0.21.
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Water resources estimation under changing flow regimes is required for planning and smooth distribution of water to provinces. Since the hydrological parameters are changing significantly due to climate change, the changes in the pattern of flow regimes are definite. The objective of present study was to assess the spatial and temporal hydro variability of Indus basin. The data of Kabul river at Nowshera before its confluence with Indus river were collected from Surface water Hydrology Project (SWHP), WAPDA. The seasons were divided as three and six month keeping in view the hydrological cycle. Trends and variation were investigated by applying the Mann-Kendall test and Sen’s method. The presence of trends tested at different significant level, 99.9%, 95% and 90%. The overall analysis indicates that there is more flow variation on seasonal basis as compared to the annual basis. The Kabul river showed decreasing trend in the maximum mean annual discharge, whereas the minimum mean annual discharge showed increasing trend. It was concluded that Kabul river showed decreasing trend in annual mean and maximum discharge, whereas annual minimum discharge showed increasing trend. It was also noticed that Kabul river mean minimum discharge time series decreased during 1961-1985, whereas it increased during 1986-2010. It was also found that annual mean and maximum discharge decreasing rate was greater during 1986-2010. It was further concluded that each decade experienced one or two years of both dry and wet periods and that 2000-2004 was the driest period in the history of Kabul River.