Extreme hydrological phenomena in the forest steppe and steppe zones of Ukraine under the climate change

Valeriya Ovcharuk,Mariia Myroschnichenko,Nataliya Kichuk,Eugene Gopchenko,Zhannetta Shakirzanova,Liliia Kushchenko

doi:10.5194/piahs-383-229-2020

Abstract

Abstract. Nowadays, during the period of the global climate change, scientists around the world have noticed an increased incidence of extreme natural disasters. The authors of the study suggested methods of using climate change as a part of a genetic model of maximal floods runoff. This model makes possible the introducing of “climate changes” directly through the maximal stocks of snow and precipitation during the spring flood and runoff coefficients. The object of study is the basin of the Southern Bug – one of the largest rivers in Ukraine, which flows within two geographical zones – forest-steppe and steppe. Overall results using scenario RCP 4.5 showed a decrease of runoff by the end of 2050 from 20 % in the north part of the basin (the forest-steppe zone) to 50 % – in the south (the steppe part of basin). On the other hand, the characteristics of minimal river flow in the Southern Bug basin – winter and summer low waters had been analyzed. One option for low water flow simulation is to study the connection between the drought index (e.g. SPEI) and the minimal water. Studies show that such correlation exists, so knowing the forecast of drought index it is possible to project the value of minimal water discharge, which is the object of the research.

Highlights

Global climate change has been studied in recent decades, practically all over the world
The authors have proposed a new modified version of the operator model for determining the maximal runoff of spring flood, which allows taking into consideration the possible impact of climate change on the estimated values of the maximal modules 1 % probability of exceeding
Climate change is taken into account by introducing a separate coefficient, based on a comparison of the main parameters of the method obtained on the basis of current data, and similar values obtained from climatic modeling data

Summary

Introduction

Global climate change has been studied in recent decades, practically all over the world. In Europe, according to the European Environment Agency (EEA, 2019), in the EEA member states, the total economic losses from climate-related extremes over the period 1980– 2017 reached approximately EUR 453 billion. The average annual economic losses in the EEA member states varied from EUR 7.4 billion in 1980–1989 to EUR 13.0 billion in 2010–2017. The most expensive climate-related extremes in the EU member states included floods in Central Europe in 2002 (over EUR 21 billion), drought and heat waves in 2003. The considerable economic losses and potential danger from climate-related extremes are of great interest to scientists all over the world and they need to be studied, systematized and modeled for probabilistic and operational forecasting. In Ukraine, the research of the water regime of rivers and its changes nowa-

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Conclusion