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Kogan F.,National Oceanic and Atmospheric Administration | Kussul N.,Ukrainian Academy of Sciences | Kussul N.,Kharkiv Polytechnic Institute | Adamenko T.,Ukrainian Hydrometeorological Center | And 11 more authors.
International Journal of Applied Earth Observation and Geoinformation | Year: 2013

Ukraine is one of the most developed agriculture countries and one of the biggest crop producers in the world. Timely and accurate crop yield forecasts for Ukraine at regional level become a key element in providing support to policy makers in food security. In this paper, feasibility and relative efficiency of using moderate resolution satellite data to winter wheat forecasting in Ukraine at oblast level is assessed. Oblast is a sub-national administrative unit that corresponds to the NUTS2 level of the Nomenclature of Territorial Units for Statistics (NUTS) of the European Union. NDVI values were derived fromthe MODIS sensor at the 250 m spatial resolution. For each oblast NDVI values were averaged for a cropland map (Rainfed croplands class) derived from the ESA GlobCover map, and were used as predictors in the regression models. Using a leave-one-out cross-validation procedure, the best time for making reliable yield forecasts in terms of root mean square error was identified. For most oblasts, NDVI values taken in April-May provided the minimum RMSE value when comparing to the official statistics, thus enabling forecasts 2-3 months prior to harvest. The NDVI-based approach was compared to the following approaches: empirical model based on meteorological observations (with forecasts in April-May that provide minimum RMSE value) and WOFOST crop growth simulation model implemented in the CGMS system (with forecasts in June that provide minimum RMSE value). All three approaches wererun to produce winter wheat yield forecasts for independent datasets for 2010 and 2011, i.e. on data that were not used within model calibration process. The most accurate predictions for 2010 were achieved using the CGMS system with the RMSE value of 0.3 t ha-1 in June and 0.4 t ha-1 in April, while performance of three approaches for 2011 was almost the same (0.5-0.6 t ha-1 in April). Both NDVI-based approach and CGMS system overestimated winter wheat yield comparing to official statistics in 2010, and underestimated it in 2011. Therefore, we can conclude that performance of empirical NDVI-based regression model was similar to meteorological and CGMS models when producing winter wheat yield forecasts at oblast level in Ukraine 2-3 months prior to harvest, while providing minimum requirements to input datasets. © 2012 Elsevier B.V. Source

Kogan F.,National Oceanic and Atmospheric Administration | Adamenko T.,Ukrainian Hydrometeorological Center | Kulbida M.,Ukrainian Hydrometeorological Center
NATO Science for Peace and Security Series C: Environmental Security | Year: 2011

Every year weather vagaries have caused shortfalls of agricultural production regionally and every 3-4 years these shortfalls occurred globally. Therefore, early assessment of crop losses in response to weather fluctuations is an important task for the estimation of global, regional and countries food supply/demand, donor's decision to assists the nations in need and to those receiving the assistance. The new satellite-based technology has been recently developed to provide timely and accurate crops' monitoring and assessments. This technology includes the theory, algorithm, data base and operational implementation of vegetation health (VH) assessments from observations provided by the Advanced Very High Resolution Radiometer (AVHRR) flown on NOAA operational polar-orbiting satellites. Several AVHRR-based VH indices were developed and used to provide weekly cumulative estimation of moisture, thermal and health conditions of vegetation canopy throughout the growing season. The indices were calculated for the entire 1981-2010 period of the AVHRR sensor in space and were compared with regional crop yields in the two dozens of countries. Strong correlation between wheat (both winter and spring), corn, soybeans and sorghum yield and VH indices was found during the critical period of the tested crops. The test results showed that VH indices can be used as proxy for early (2-5 months in advance of harvest) assessment of crop yield with the errors of estimation less than 10%. This paper discusses utility of space observations for early forecasting regional crop yield in Ukraine, with specific emphasis on 2-5 months warning of weather-related losses in agricultural production and their impact on agricultural supply/demand and food security. © Springer Science+Business Media B.V. 2011. Source

Kryvobok O.,Ukrainian Hydrometeorological Research Institute | Kulbida M.,Ukrainian Hydrometeorological Center | Savchenko L.,Ukrainian Hydrometeorological Center
NATO Science for Peace and Security Series C: Environmental Security | Year: 2011

Severe weather events associated with deep convection such as flash floods, large hail, damaging winds and even occasional tornadoes are reported every year in Ukraine. There is an increased demand for the assessment of operational strategies for the forecasting and/or nowcasting of severe convective clouds in this country. The forecast of the location of severe convective clouds in advance of their formation is possible with the use of remote sensing techniques such as radar and/or satellite. Ukraine currently has a few EUMETCast stations in the different parts of the country which provide real-time geostationary Meteosat Second Generation satellite images. An experience in the use of Meteosat for detection and tracking of severe convective clouds is discussed. © Springer Science+Business Media B.V. 2011. Source

Adamenko T.,Ukrainian Hydrometeorological Center | Prokopenko A.,Ukrainian Hydrometeorological Center
NATO Science for Peace and Security Series C: Environmental Security | Year: 2011

The agrarian sector is an important component of the Ukrainian economy. Within this sector about 20% of able-bodied citizens of the country are employed and 12-15% of the gross domestic product is formed. During previous years simultaneous with the tendency of improved agricultural technology, the significant fluctuations of crops productivity owing to weather conditions, first of all owing to droughts, increase. Their frequency and intensity rise. Every 2-3 years the drought covers up to 20-40% of the country territory. Crop losses owing to droughts can run up to 50% and more. There is a dangerous tendency of drought distribution over territory which earlier belonged to a zone of sufficient moisture. In the Ukraine, climate fluctuations affecting crop production account for a 20-50% loss of winter crops and 35-75% loss of summer crops. © Springer Science+Business Media B.V. 2011. Source

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