Detecting climate change in Ukraine: trends, prediction and extreme events

In this study the trends and variations in 25 extreme temperature and precipitation indices
defined by ETCCDI, are examined using trend method, probability distribution analysis and
spatial statistics for periods of 71 to 137 years for 16 stations evenly distributed in Ukraine. Data
on the indices were obtained from www.ecad.eu.
Since 1981, temperature has increased by about 1ºC in all stations in question relative to the
period of 1945-1980. Analysis of the temperature indices indicates that during the 20th and the
beginning of the 21th century there is significant warming which is particularly pronounced in
annual mean and annual maximum temperatures. Occurrence of more summer days, warm days
and tropical nights and warm spell duration reached the record highest level, and conversely
occurrence of frost and ice days, cold days and cold spell duration fall to a record low for the last
three decades in the most of study territory.
Since 1981, precipitation amount has grown by 30-50 mm relative to the period of 1945-1980 for
the most of Ukrainian territory, except Uzhhorod and Uman where precipitation amount has
remained the same. For Ukraine average, an increase in maximum daily and maximum 5 days
precipitation amount, the maximum number of consecutive wet days, heavy and very heavy
precipitation days, and a decrease in the maximum number of consecutive dry days are observed
for the last three decades.
The analysis of the spatial distribution of trend of precipitation and temperature indices showed
that there are large differences between regions of Ukraine, and coherence of spatial distribution
of trends of various indices is low.
Spectral analysis and harmonic regression techniques were used to derive simulated and
predicted (2019-2050) values of annual precipitation and annual mean temperature and four
indices such as maximum value of daily maximum temperature, minimum value of daily
minimum temperature, the highest 1-day precipitation amount and maximum number of
consecutive dry days for some stations such as Kerch (the Crimean Peninsula), Kyiv (situated in
north-central Ukraine along the Dnieper River), Lubny (Dnieper Lowland), Lviv and Shepetivka
(Podillia Upland), Uzhhorod (Transcarpathia), Uman (Dnieper Upland).
Annual mean temperature and maximum value of daily maximum temperature were predicted to
increase by 0.33°C per decade in the period of 2019-2050 with respect to 1981-2018, while
minimum value of daily minimum temperature was predicted to grow slightly faster (by 0.43-
0.63ºC per decade).
Precipitation was predicted to increase for the stations in question by 20-66 mm up to 2050
relative to 1981-2018 and conversely maximum number of consecutive dry days will slightly
decline except Lubny where increase in an aridity index was predicted. In the next three decades
changes in maximum daily precipitation will be various: in Shepetivka and Kyiv such
precipitation will be decreased and in other stations increasement in such precipitation will be up
to 6 mm till 2050 with respect to 1981-2018.