Trends in precipitation and streamflow during low-flow period over territory of Belarus

Introduction

Climate changes over the territory of Belarus noted in the early 1970s. These changes became more significant since the 1990s [1] and were reflected in the rivers regime [2-4]. The formation of river runoff is associated with many natural factors, the main of which is the precipitation. Significant increases or decreases of water resources depends on anomalies in the moistening regime.

In recent years, droughts and dry conditions in the atmosphere, soil and water systems become more frequent in the European region, including the territory of Belarus. At the same time maximal totals of precipitation increased. Trends in the frequency of meteorological droughts in Europe based on the Standard Precipitation Index (SPI) over three months (SPI-3) show an increase in frequency since 1950 in southern Europe and major part of central Europe, but in many parts of northern Europe the frequency of droughts has decreased [5]. The droughts frequency is expected to increase by the middle of the 21st century (2041-2070 compared to 1981-2010) over the region, in particular in southern Europe, with a decrease in the number of droughts projected only for limited parts of northern Europe [6].

Driest month runoff trends 1950-2015 show a decrease in southern Europe and most of Central Europe, but in northern Europe the minimum flow has increased [7, 8].

The territory of Belarus is located in the transition zone between the north, where there is an increase in precipitation and the minimum flow increases, and in the south, where there is a decrease in precipitation and minimum flow. Over the past 30 years, covering the period of climate warming in Belarus (1989-2019), there are no significant changes in annual precipitation amounts, but at the same time, dry phenomena are observed more often [9].

Fig.1. Trends in precipitation over territory of Belarus
Fig.1. Trends in precipitation  over territory of Belarus

Keywords

сlimate change, precipitation, droughts, streamflow, low-flow season

Main method

Method Map

Main results

Fig.3. Trends in daily maximal totals (mm)
Fig.3. Trends in daily maximal totals (mm)
Fig.2. Trends in rainfall duration (h)
Fig.2. Trends in rainfall duration (h)

Fig.4. Trends in days number with relative humidity below 30%
Fig.4. Trends in days number with 
relative humidity below 30%
Fig.5. Changes in repeatability of atmosphere droughts
Fig.5. Changes in repeatability
of atmosphere  droughts

Changes in winter-spring streamflow

Fig.6. Trends in winter low-flow streamflow
Fig.6. Trends in winter low-flow streamflow
Fig.7. Trends in spring streamflow
Fig.7. Trends in spring  streamflow

Changes in summer-autumn streamflow

Fig.8. Trends of low-flow specific discharges
Fig.8. Trends of low-flow specific discharges
Fig.9. Trends of summer floods specific discharges
Fig.9. Trends of summer floods specific discharges   
Fig.10. Changes in repeatability of hydrological droughts
Fig.10. Changes in repeatability of  hydrological droughts

Main conclusions

The study presents an assessment of the precipitation and surface streamflow within the territory of Belarus. The tendencies of monthly precipitation, maximal daily totals and duration of rainfall were detected; streamflow characteristics, such as the highest and lowest discharges for the low-flow seasons and highest discharges of snow and rain floods were estimated. The Standard Precipitation Index and Standard Streamflow Index were calculated to estimate the drying conditions over territory of Belarus. Despite the insignificant change of the annual precipitation during the period of 1989-2019, the intensification of rain falling has increased over territory of Belarus but at the same time the number of meteorological droughts growth in May-September. The streamflow rate didn’t change significant but the highest rain floods discharges and/or the lowest discharges during low-flow season has growth (except the Neman River basin) while hydrological droughts repeatability also has increased in all river basins of the study region.

References

  1. Jaagus, J., Aasa, A., Aniskevich, S., Boincean, B., Bojariu, R., Briede, A., Danilovich, I., Castro, F. D., Dumitrescu, A., Labuda, M., Labudová, L., Lõhmus, K., Melnik, V., Mõisja, K., Pongracz, R., Potopová, V., Řezníčková, L., Rimkus, E., Semenova, I., Stonevičius, E., Štěpánek, P., Trnka, M., Vicente-Serrano, S. M., Wibig, J., & Zahradníček, P. (2021). Long-term changes in drought indices in eastern and central Europe. International Journal of Climatology, 1– 25. https://doi.org/10.1002/joc.7241
  2. Danilovich I. The Past and Future Estimates of Climate and Streamflow Changes in the Western Dvina River Basin / Danilovich I., Zhurvalev S., Kurochkina L., Groisman P. // Frontiers in Earth Science, section Interdisciplinary Climate Studies. – 2019. - № 7(204). – 16 p. https://doi.org/10.3389/feart.2019.00204
  3. Rutgersson, A., Kjellström, E., Haapala, J., Stendel, M., Danilovich, I., Drews, M., Jylhä, K., Kujala, P., Guo Larsén, X., Halsnæs, K., Lehtonen, I., Luomaranta, A., Nilsson, E., Olsson, T., Särkkä, J., Tuomi, L., and Wasmund, N.: Natural Hazards and Extreme Events in the Baltic Sea region, Earth Syst. Dynam. [preprint, 2021], https://doi.org/10.5194/esd-2021-13

Author

Irina Danilovich, Ph.D.  Assoc. Professor, Docent
Department of Earth Science and Hydrometeorology

Belarus State University
Minsk, Belarus
irina-danilovich@yandex.ru

Last modified: 2021-10-19
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