Interannual precipitation variations in the mid-latitude Asia and their association with large-scale atmospheric circulation

Abstract

This study analyzed the spatial differences of the precipitation variations in the mid-latitude Asia and their possible physical mechanisms during 1960-2009. The annual precipitation showed an opposite variations between the westerlies-dominated arid Central Asia (ACA) and monsoon-dominated North China (NC) during the study period. Given the different contributions of seasonal precipitation to annual total precipitation in ACA and NC, the atmospheric circulation anomalies during the major precipitation seasons (winter in ACA/summer in NC) were analyzed. In winter, negative North Atlantic Oscillation may cause negative height anomalies over the north side and positive anomalies over the south side of the ACA. Together, the enhanced pressure gradient and anomalous westerly wind brings more water vapor to ACA, and leaves less precipitation in NC. In summer, the low-pressure anomalies in Northeast China, along with a weaker summer monsoon and negative height anomalies in Eastern Europe together contribute to reduced (excessive) summer precipitation in NC (ACA). The interactions between ENSO and NAO may result in the opposite precipitation variations between ACA and NC. A significant 2-3-year cycle is identified in ACA, which is linked to the variations of westerly circulation in the middle troposphere.

Environmental variability and human activity over the past 140 years documented by sediments of Ebinur Lake in arid central Asia

“…In addition, meltwater from snow can have a direct impact on primary productivity in arid lands. Measurements taken at local meteorological stations show an increase in winter precipitation, which is supported by previous studies that have attributed the observed trend toward increasing amounts of annual precipitation in mid-latitude Asia to changes in winter precipitation (Huang et al, 2013). It is inferred that the climatic conditions since the 1940s, promoted watershed primary productivity more effectively.…”

Tree-Ring Response to Snow Cover and Reconstruction of Century annual Maximum Snow Depth for Northern Tianshan Mountains, China

“…Most of these interannual cycles (5.3, 3.5-3.8, 2.8, 2.2, and 2.0 yr) in our reconstruction fall within the range of the El Niño Southern Oscillation (Allan et al, 1996). In addition, the 2-3-yr cycle that can also be identified in arid Central Asia (Huang et al, 2013), is linked to variations of the westerly circulation in the middle troposphere, which may indicate that our reconstructed maximum snow depth variability might have some teleconnections with oscillations of the landatmosphere-ocean circulation systems. Furthermore, these high-frequency cycles can often be found in den- droclimatic studies of the Tianshan Mountains (e.g., Zhang et al, 2009Zhang et al, , 2013Zhang et al, , 2015bZhang et al, , 2016 and other arid and semiarid sites in northwestern China (Liang et al, 2009;Chen et al, 2011;Liu et al, 2011).…”

“…The Tianshan Mountains comprise the largest mountain range in arid Central Asia, which is called the "wet island" of Central Asia. The climate of the Tianshan Mountains is dominated by westerly winds and it plays an important role in global climate change research (Huang et al, 2013). It is vital to understand the past climatic changes in this area and to explore possible influence mechanisms regarding the sustainable use of the regional water resources.…”

Variations in the oxygen isotopic composition of precipitation in the Tianshan Mountains region and their significance for the Westerly circulation

“…Research over the past 50 years has shown that there is a trend of increasing precipitation amount in ACA but a decreasing trend in northern China (Huang et al, 2013). During the last millennium, synthesized proxy moisture/precipitation records indicate a drier Medieval Climate Anomaly (MCA) and a wetter Little Ice Age (LIA) in ACA than in monsoonal northern China (Chen et al, 2015).…”