Comparison of the Causes of High-Frequency Heavy and Light Snowfall on Interannual Timescales over Northeast China

Lushan Wang,Zhiqing Xu,Ke Fan

doi:10.3390/atmos11090936

Abstract

This study investigates and compares the reasons for high-frequency heavy and light snowfall in winter on interannual timescales over northeast China (NEC) during 1961–2017. Results indicate that the frequency and its variability are strong over southeastern NEC for heavy snowfall but over northern NEC for light snowfall. Analysis of the annual cycle shows that the maximum frequency of heavy snowfall occurs in November and March due to more warm–wet air masses and increased atmospheric instability, and that of light snowfall occurs in December–January due to drier conditions and increased atmospheric stability. The frequency of heavy snowfall exhibits an increasing trend which partly results from the warming trend in NEC, while that of light snowfall shows a decreasing trend. High-frequency heavy snowfall is associated with a positive North Atlantic Oscillation (NAO), warmer regional air temperatures, an increased water vapor budget associated with an anomalous anticyclone occupying the Kuril Islands, and relatively unstable atmospheric layers. High-frequency light snowfall is associated with a strengthened East Asian winter monsoon, colder regional air temperatures, a decreased water vapor budget, and relatively stable atmospheric layers. High-frequency heavy and light snowfall are both related to eastward-propagating quasi-stationary waves over Eurasia, but with different features. The waves of the former are located in midlatitude Eurasia and related to the positive phase of the NAO. The waves of the latter exhibit two pathways, located in midlatitude and northern Eurasia, respectively. The northern one can be partially attributed to a weak polar vortex. In addition, higher sea surface temperatures of the Kuroshio Extension may contribute to high-frequency heavy snowfall.

Highlights

Snowfall is a major weather phenomenon in wintertime over northeast China (NEC)
Wang [23] revealed that, compared with light snowfall events, the atmospheric circulation anomalies at mid-high latitudes that are associated with more heavy snowfall events in northern China are similar but with larger meridional variation, and intense snowfall has a closer relationship with the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO), the mechanistic links remain unexplored
Previous research states that the warming air temperature are associated with the strengthening intensity of near-surface that the warming air temperature are associated with the strengthening intensity of near-surface water water transportation for snowfall [34]

Summary

Introduction

Snowfall is a major weather phenomenon in wintertime over northeast China (NEC). Snowfall greatly impacts the growth of grain seedlings, which determines the annual grain production in NEC. The highest frequency of heavy snowfall in winter in northern China is mainly located in NEC [16]. Wang [23] revealed that, compared with light snowfall events, the atmospheric circulation anomalies at mid-high latitudes that are associated with more heavy snowfall events in northern China are similar but with larger meridional variation, and intense snowfall has a closer relationship with the North Atlantic Oscillation (NAO) and AO, the mechanistic links remain unexplored. We provide a new perspective on the comparison between these two kinds of snowfall in NEC After excluding their same years, we examine which large-scale atmospheric circulation patterns are favorable for high-frequency heavy and light snowfall, whether or not the associated physical mechanisms are similar, and what the cause of any differences might be. The final section summarizes our research and discusses some remaining issues

Data and Methods

Climatic Features

Climatological

Physical Mechanisms

Conclusions