Annual and seasonal precipitation dynamics in the South of Russia in the context of climate change

The study analyzed spatiotemporal trends in the amount, heterogeneity, and extremeness of precipitation in the South of Russia in the period 1960–2022. The highest annual precipitation, at 1634 mm, occurs along the Black Sea coast of the Caucasus. As one moves north and east, precipitation noticeably decreases to a minimum value of 216 mm in the Ergeninskaya Upland and the western part of the Caspian Lowland. The spatial distribution of seasonal precipitation correlates with this spatial pattern. Almost throughout the entire study areas, a positive but mostly insignificant trend in annual precipitation was observed with an average growth rate of 5.25 mm/decade. However, growth tendency were only observed in winter, autumn and spring, with average rates of 1.46, 3.77 and 2.45 mm/decade, respectively. An increase in the unevenness of precipitation during the year was observed mostly in the western part of the Caspian Lowland and on the Ergeninskaya Upland. Extreme precipitation indicators (SDII, R10mm, Rx1day, Rx5day) varied from minimum values in the west of the Caspian Lowland to maximum values on the Black Sea coast (4.85–14.0 mm/day, 4.5–52.2 days, 25.4–90 mm, 36.0–166.8 mm, respectively). Changes in extreme precipitation in all seasons were mostly insignificant, but all indicators (except R10mm) showed positive dynamics (average 0.04 mm/days/decade, 0.30 and 0.63 mm/decade, respectively), and the most pronounced increase occurring in autumn. Spatially, the most pronounced increase in the number of extreme precipitations was observed on the Black Sea coast of the Caucasus.