Ensembles of Euro-CORDEX RCMs for assessment of specialized climate indices in Ukraine

Regular update of climate projections is a crucial task in all countries since such data should be a basis for development further adaptation measures on all levels from national down to local. And the more detailed data is available the more reliable and focused measures to combat climate change could be developed. At the moment data of EuroCORDEX initiative with 0.1^o spacing is the most suitable, detailed and freely available dataset for Ukraine. We used bias-adjusted daily and monthly air temperature and precipitation datasets projected by 34 regional climate models (RCMs) for RCP4.5 and RCP8.5 scenarios for 3 future periods: near-term 2021-2040, mid-term 2041-2060 and far-term 2081-2100. Further bias-adjustment by the delta-method has been applied for the RCMs ensemble means when differences in temperatures (or ratio in case of estimations for precipitation) in future periods were added to (or for precipitation - multiplied by) values in the base period 1991-2010, obtained from the E-OBS v20.0e data. The Delta method applied provides more reliable results and allows to effectively exclude systematic biases in RCMs.

At the same time, in response to practical needs not only main climate parameters such as air temperature and precipitation should be projected under different scenarios but specialized climate indices that are different for different sectors. We’ll present as an example a set of indices relevant to forestry which is among the most vulnerable sectors to climate change in Ukraine. They are as follows: daily and annual temperature ranges, continentality, the coldest month temperature, heat and moisture supply during warm season with t>0^o, and types of climates by Worobjov index. All climate indices for the base period 1991-2010 and past WMO period 1961-1990 are estimated from the E-OBS data. To visualize the above indicators Ukraine atlas has been developed in QGIS application which represents 2 past and 3 future periods for 2 scenarios.