A method was developed for assessing soil water content W (as basic indicator of water availability), evapotranspiration Ev, and other water and heat regime (WHR) elements of agricultural regions during vegetation season (VS).The base of the method is the physicalmathematical model of land surface-atmosphere water and heat exchange adapted to satellitederived estimates of vegetation and meteorological characteristics (VMC).These estimates used as model parameters and input variables were obtained by thematic processing data from radiometers-scanners AVHRR/NOAA, SEVIRI/Meteosat-10, -11, -8, and MSU-MR/Meteor-M No. 2 in the visible and IR ranges.Soil surface moisture (SSM) estimates used to calculate W were produced from measurements of scatterometer ASCAT/MetOp in the microwave range.The case study were carried out for forest-steppe territory of 2 27 300 km 2 located in the Black Earth Region of European Russia and for arid steppe territory of the Saratov and Volgograd Trans-Volga region of 66 600 km 2 for VS of 2016-2018.The main results of the study are: procedures to assimilate satellite-derived VMC estimates in the model were developed; the possibilities to use ASCAT-derived SSM estimates for calculating W were confirmed; W, Ev and other WHR characteristic estimates were obtained for the named VS as distributions over the area under study.

Представлены результаты компьютерного анализа режимов водного стресса орошаемых посевов люцерны, кукурузы и сои на уровне отдельного агроценоза с использованием SWAP-модели.Для сопоставления результатов компьютерного моделирования водного стресса с биопродуктивностью были использованы данные подспутникового полевого мониторинга, проведённого в 2012 г. на полях ряда хозяйств, расположенных на территории Саратовского Заволжья.В результате были выявлены связи рассчитанных величин накопленного за период вегетации водного стресса отдельных посевов с их урожайностью.Компьютерная модель SWAP, использованная для расчёта водного стресса, включала блоки описания водного и теплового режимов для системы «атмосфера -агроценоз -почва -грунтовые воды», а также массивы данных для формирования граничных условий и гидравлических характеристик почвенно-грунтовой толщи.Массивы данных, воспроизводящие граничные условия на дневной поверхности, были сформированы по результатам наземного и космического мониторинга, а также диспетчерского контроля реализации поливов сельскохозяйственных посевов

Представлены оценки характеристик водного и теплового режимов территории части Цент ральноЧернозёмного региона, преимущественно занятой посевами сельскохозяйственных культур, для сезонов вегетации 2016-2017 гг.Данные оценки были получены с помощью мо дели вертикального влаго и теплообмена поверхности суши с атмосферой LSM (Land Surface Model) при использовании спутниковой информации о состоянии подстилающей поверх ности и метеорологических условиях.Эта информация была представлена данными изме рений радиометров AVHRR (ИСЗ NOAA), МСУМР (ИСЗ «МетеорМ» № 2), SEVIRI (ИСЗ Meteosat10, 11, 8).В число рассчитываемых с помощью модели характеристик входят вла гозапасы почвы, суммарное испарение, вертикальные тепловые потоки, температура подсти лающей поверхности, влажность и температура почвы на разных глубинах.В рамках данного подхода для исследуемой территории были тестированы методики использования в модели оценок метеорологических характеристик (осадков, температуры поверхности растительного покрова и почвы, эффективной температуры подстилающей поверхности) и характеристик растительности (вегетационного индекса NDVI, проективного покрытия растительностью B, листового индекса LAI и др.), построенных по данным новых спутников (Meteosat11, 8).Проведено сравнение с фактическими значениями величин влагосодержания почвы W и сум марного испарения Ev, рассчитанных с помощью модели, в их динамике за сезон вегетации при различных вариантах оценки характеристик растительности и метеорологических харак теристик, построенных по данным измерений всех названных сенсоров.Погрешность оцен ки оказалась в пределах 15 % для W и 25 % для Ev.Показана возможность использования при моделировании оценок влажности поверхности почвы, полученных по данным измерений скаттерометра ASCAT/MetOp в СВЧдиапазоне, для выбора начальных условий при расчётах влагозапасов почвы и для расчёта испарения с поверхности почвы Ev g , являющегося одной из характеристик водного режима территории.Рассчитанные значения Ev g использовались непо средственно при расчёте влагосодержания почвы, а также

Представлены оценки характеристик водного и теплового режимов участков территории Саратовского и Волгоградского Заволжья, занятых посевами сельскохозяйственных культур, для вегетационного сезона 2012 г. Оценки получены при помощи моделей вертикального влаго- и теплообмена поверхности суши с атмосферой SVAT и SWAP и модели SEBS с использованием спутниковых данных о состоянии подстилающей поверхности и метеорологических условиях, а также аддитивной модели водоудерживания для текстурных почв.

The method has been developed to evaluate water and heat balance components for vegetation covered area of regional scale based on the refined physical-mathematical model of vertical water and heat exchange between land surface and atmosphere (Land Surface Model, LSM) for vegetation season adapted to satellite information on land surface and meteorological conditions. The LSM is accommodated for utilizing satellite-derived estimates of vegetation and meteorological characteristics as model parameters and input variables. Estimates of these characteristics presented as distributions of their values over the study area have been obtained from AVHRR/NOAA, MODIS/EOS Terra and Aqua, SEVIRI/Meteosat-9, -10 data. To build such estimates methods and technologies have been developed and refined using results of thematic processing measurement data from these sensors. Among them the original Multi Threshold Method (MTM) has been developed and tested to calculate daily precipitation sums using rainfall intensity estimates retrieved from AVHRR and SEVIRI data with subsequent replacement of ground-measured rainfall amounts by these daily rainfalls. All technologies have been adapted to the study area with square of 227300 km 2 being the part of the Central Black Earth Region of European Russia. Developed earlier procedures of utilizing satellitederived estimates of vegetation and meteorological characteristics (including precipitation) in the model have been refined and verified. Final result of modeling is the fields of soil water content, evapotranspiration and other water and heat balance components of the region under study for years 2012–2014 vegetation seasons.

Представлены результаты использования оценок характеристик растительности и метео-

The method of the AVHRR-3 (NOAA) radiometer measurement data subject processing is produced for the retrieval of underlying surface temperature and several vegetation characteristics under cloud-free conditions. A technology for deriving the values of these parameters from the MODIS (EOS/Terra and Aqua) radiometer data is developed. The estimation of the temperature and vegetation characteristics is carried out for the Seim River basin (Kursk region) with the catchment area of 7460 km 2 for 2003–2005 vegetation seasons. Practical coincidence of estimations of AVHRR- and MODIS-derived temperatures, as well as the coincidence with ground observation results, is revealed. Statistics of these estimation errors is analyzed. Satellite-derived estimations of land surface temperature (LST) and vegetation characteristics are used for the calibration and verification of the developed model of the vertical heat and water transfer in the soil-vegetation-atmosphere system (SVAT). The model is intended for calculations of evapotranspiration, soil water and heat content, latent and sensible heat fluxes, and other water and heat balance components. The abilities to compute these parameters using the satellite estimations of the leaf area index and projective vegetation cover fraction as the model parameters and LST satellite estimations as the model input variable are investigated.

A physical and mathematical model of the vertical heat and moisture transfer and the carbon exchange in the soil-vegetation-atmosphere system is proposed that includes the interaction between these processes. The model describes the interception of precipitation by plants and its further evaporation, transpiration, evaporation from a soil surface as well as vertical moisture transfer, photosynthesis, and plant and soil respiration. The model has been verified against data from observations of heat, moisture, and carbon dioxide fluxes at a grassland site (international FIFE experiment, Kansas, United States), in a pine forest (BOREAS, Saskatoon, Canada), and in a broad-leaved mixed forest (FLUXNET measurements in the southeastern United States). Numerical experiments with the models have been conducted to estimate the influence of soil moisture and atmospheric CO 2 concentration on transpiration and carbon exchange of the vegetation cover.

A coupled model of the hydrological and carbon cycles in the soil–vegetation–atmosphere system is suggested. The model describes the interception and evaporation of precipitation by canopy, transpiration, vertical transfer of soil moisture, photosynthesis, the interaction between transpiration and photosynthesis, and plant and soil respiration. The validation of this model was carried out using the FIFE measurements from a grassland site in Kansas, the BOREAS measurements from a jack pine forest site in Saskatchewan, and the observations conducted within a deciduous forest in the southeastern United States. The model results show a good agreement with experimental data. The model was shown to adequately describe the influence of soil moisture and atmospheric CO2 concentration on transpiration and net ecosystem CO2 exchange.

The paper discusses the retrieval of land surface temperatures (LST) from AVHRR data and their utilization in the model of the hydrological cycle (HC) for river basin. The Seim River basin with watershed area about 7500 sq. km situated in forest-steppe zone of the Central Russia (Kursk region) was chosen for investigation. A "local" split-window algorithm has been developed and tested for LST derivation from cloud-free AVHRR data. The algorithm has been applied to produce LST maps for the Kursk region and various dates during 1997-1999 vegetation seasons. Comparison with synchronous collocated in situ measurements gives RMS errors in the range (1.5-2.5)degreesC.The model of the HC for river basin describes vertical moisture and heat transfer in the system "soil-plant-atmosphere", overland flow formation, and flow in river network and allows to estimate an effect of land surface heterogeneities on evapotranspiration (Ev) and other HC components.The satellite LST field estimates were used in experiments with the HC model in order to validate the output modeling results and to specify the initial conditions. In both cases the experiments have demonstrated that using satellite data leads to improved output results.

The effects of small-scale spatial heterogeneities of soil, land use and vegetation on area-averaged components of the water balance of a river basin are investigated. Different parameterizations of these effects are tested on the base of the distributed model of the hydrological cycle. The model includes a description of the vertical moisture transfer in the “soil-vegetation-atmosphere” system, the overland flow and the river channel system routing. The heterogeneities are divided into deterministic (mosaic) and stochastic components. To parameterize stochastic components the procedures based on probability distributions of basin constants and the theory of fractals were used.

A physically based model of moisture transfer in the soil-canopy-atmosphere system, fitted to measured data in wheat fields, was applied to calculate the sensitivity of évapotranspir ation to the combined effect of possible C02-induced climate changes and the direct impact of doubling C02 content in the atmosphere. The impact of carbon dioxide was taken into account by changing the stomatal resistance and the leaf area index. Several climate change scenarios were used. Simulation studies showed that when the changes of a number of climatic and plant factors are considered, évapotranspiration responses can differ greatly from those that consider only temperature change. The temperature effect of the increase in C0 2 content in the atmosphere can be compensated by changes in the physiological parameters of vegetation. Thus, under certain conditions, one can expect a decrease in évapotranspir ation instead of an increase such as is predicted by a number of models which neglect the direct effects of C0 2 on plant behaviour. Sensibilité de l'évapotransp iration et de l'humidité du sol sur des champs de blé, aux modification du climat et à l'effet direct de l'augmentation de concentration de l'anhydride carbonique Résumé Etabli sur des bases physiques, un modèle de transfert de l'humidité dans le système sol-surface supérieure de la couverture végétale-atmosphère a été ajusté aux données des mesures sur des champs de blé pour calculer la sensibilité de l'évapotranspiration aux effets combinés du changement de climat possible résultant de l'augmentatio n de concentration de C0 2 et de l'impact direct du doublement du contenu de C0 2 dans l'atmosphère. L'impact de l'anhydride carbonique a été pris en compte en changeant la résistance stomatique et l'indice de la surface foliaire. Quelques scénarios probables climatiques ont été utilisés. Les études de simulation ont montré que lorsque l'on considère les modifications d'un certain nombre de facteurs climatiques ou biologiques les réponses de l'évapotranspiration peuvent différer largement de ceux obtenus en ne considérant que