Methods of essential variables determination for the Earth’s surface state assessing

1Yailymov, BYa., 2Lavreniuk, MS, 3Shelestov, AYu., 3Kolotii, AV, 4Yailymova, HO, 1Fedorov, OP
1Space Research Institute of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, Kyiv, Ukraine
2Space Research Institute of the National Academy of Sciences of Ukraine and the National Space Agency of Ukraine, Kyiv, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
3Space Research Institute of the National Academy of Science of Ukraine and the State Space Agency of Ukraine, Kyiv; National Technical University of Ukraine «Kyiv Polytechnic Institute», Kyiv, Ukraine
4Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
Space Sci.&Technol. 2018, 24 ;(4):26-40
Publication Language: Ukrainian
Abstract: 
In this paper, we describe the results and the methodology for a definition of land degradation indicators. The conducted work allowed us to specify the methods for obtaining quantitative estimates of land use as well as to estimate the land cover change for the territory of Ukraine over the period of time.  An analysis of existing datasets for the territory of Ukraine was carried out to estimate the changes of the land cover.
         The sets of data over the territory of Ukraine were investigated for the creation of land cover maps as well as for methods of vegetation state assessment, in particular, for assessing land degradation and LDN (Land Degradation Neutrality) supported with the UN Convention to the Combat Desertification. As the national datasets for assessment of land cover changes dynamics, the land cover maps at the territory of Ukraine for 2000, 2010 and 2016 are considered. As the data sources, the maps developed at the Space Research Institute of Ukraine are used. These maps were created using the neural network classification of the time series of satellite data. For 2000 and 2010, the land cover maps have a spatial resolution of 30 m for the entire territory of Ukraine. They were created on the basis of the Landsat-4/5/7 satellite imagery within the framework of the SIGMA FP-7 project. The performed analysis showed that the overall accuracy of global land cover maps is lower as compare with the regional land cover maps by 10% for 2000 and by 12% for 2010. For 2016, the land cover map was created with the use of satellite data from the Sentinel constellation with a spatial resolution of 10 m. An analysis of land cover changes for 2000-2010 and 2000-2016 shows the following signs of land degradation (negative trends) at the territory of Ukraine: transitions of forest to the uncultivated land (non-cropland), transitions of forest to the cultivated land (cropland), transitions of forest to the bare land. The main problems of land degradation in Ukraine were identified, namely the places where significant land cover changes took place.  The analysis of land cover change areas over the specified period of time was performed for each type of transition. We present also the results of a cross-comparison of forest areas obtained from the national land cover maps with statistics for three years (2000, 2010 and 2016).
Keywords: essential variables, land cover map, land degradation, satellite data