Studying Summer Season Drought in Western Russia

Abstract

During the 2010 summer, a severe drought impacted Western Russia, including regions surrounding Moscow and Belgorod (about 700 km south of Moscow). The drought was accompanied by high temperatures. Moscow recorded 37.8°C (100°F) for the first time in over 130 years of record keeping. The record heat, high humidity, dry weather, and smoke from forest fires caused increased human mortality rates in the Moscow region during the summer. The excessive heat and humidity in Western Russia were the result of atmospheric blocking from June through mid-August. The NCAR-NCEP reanalyses were used to examine blocking in the Eastern European and Western Russia sector during the spring and summer seasons from 1970 to 2012. We found that drier years were correlated with stronger and more persistent blocking during the spring and summer seasons. During these years, the Moscow region was drier in the summer and Belgorod during the spring seasons. In the Moscow region, the drier summers were correlated with transitions from El Niño to La Niña, but the opposite was true in the Belgorod region. Synoptic flow regimes were then analyzed and support the contention that dry years are associated with more blocking and El Niño transitions.

Changes in Blocking Characteristics during the First Part of the 21st Century

“…There was little change in the Southern Hemisphere BI. In the Northern Hemisphere, the increses found here were consistent with the results of others [6], [7], [17], [25] who examined 'partial' climatologies examining only certain reigions during certain seasons. The work of [6] implied that the period 1970 -1999 showed a relative minimum in Atlatnic Region winter season blocking.…”

“…The large increase in the occurrence and days within Pacific Region Blocking is consistent with the results of [17] who examined spring and summer blocking in this region. The work of [25] also showed a large increase in blocking for the eastern Europe and western Russia region for the spring and summer seasons as well. Only the block intensity (BI) showed a decrease over the first part of the 21st century.…”

“…This decrease is not significant at any standard level of statistical significance. [17] and [25] showed increases within the warm season in recent decades, on the other hand, [6] showed that over the Atlantic for the winter season that blocking days over the same period covered by [1] was associated with a significant minimum. Additionally, [7] showed an increase in blocking since 2000 as shown with three blocking indexes including the index used here.…”

ENSO Related Seasonal Range Prediction over South America

“…Also, [1] demonstrated that atmospheric blocking occurring over the Pacific Region can have a strong influence on the character of warm season conditions over the Missouri USA region. Additionally, the work of [4][5][6] demonstrated a strong tendency for summer season conditions to depend on the direction of the El Niño and Southern Oscillation (ENSO) transition. The work of [5] demonstrated a similar transition based dependence in western Russia, and [5,6] confirmed the tendency for atmospheric blocking to influence growing season conditions.…”

“…Additionally, the work of [4][5][6] demonstrated a strong tendency for summer season conditions to depend on the direction of the El Niño and Southern Oscillation (ENSO) transition. The work of [5] demonstrated a similar transition based dependence in western Russia, and [5,6] confirmed the tendency for atmospheric blocking to influence growing season conditions. Then [3] used this information along with time series analysis of crop yields to generate tendencies for soybean and corn yields based on the transition phase of ENSO.…”