Page 142 - 《高原气象》2023年第1期

高 原 气 象 42 卷
138

Interannual Variation in Snowfall over Songhua River Basin and Its

Relationship with West North Pacific Sea Surface Temperature
Anomalies during Boreal Winter

3
1， 2
LI Yongsheng ， CHEN Chen ， LOU Dejun ， BAO Lihong ， ZHANG Lijuan 4
3
3
（1. Heilongjiang Climate Center， Harbin 150030， Heilongjiang， China；
2. Key Opening Laboratory for Northeast China Cold Vortex Research， Shenyang 110166， Liaoning， China；
3. Qiqihar Meteorological Bureau， Qiqihar 161006， Heilongjiang， China；
4. Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service
in Cold Regions， Harbin Normal University， Harbin 150025， Heilongjiang， China）

Abstract： Based on the 103 stations precipitation over Songhua River Basin （SRB）， the reanalysis data of
NCEP/NCAR， the sea surface temperature （SST） from NOAA， the interannual variation in snowfall over SRB
and its relationship with west north Pacific SST anomalies （SSTA） during boreal winter for 1979 -2019 are in‐
vestigated by using statistical analysis methods. The results show that the snowfall over SRB during winter is
mainly characterized by its interannual variation （explains 83. 3% of total variation）， and the first leading EOF
mode of interannual snowfall anomalies of SRB during winter is dominated by a homogeneous structure （ex‐
plains 55. 3% of total variance） indicating significant covariability over the SRB. The atmospheric circulation as‐
sociated with the interannual SRB winter snowfall suggests that the above-normal （below-normal） snowfall is in‐
duced by positive （negative） geopotential height anomalies over the region from Okhotsk to Aleutian island and
negative （positive） geopotential height anomalies over the mid-low latitude to the south of Okhotsk Sea. Further
analyses indicate that the dipole structure of SSTA over WNP during winter has a profound impact on the simulta‐
neous interannual snowfall over SRB. The positive WNP SSTA dipole （positive and negative SSTA over Japa‐
nese Sea and east to the Philippines Islands， respectively） can induce positive geopotential height anomalies in
the upper troposphere and anomalous anticyclone in the lower troposphere in the mid-high latitudes over WNP，
as well as the negative geopotential height anomalies in the upper troposphere and anomalous cyclone in the low‐
er troposphere in the mid-low latitudes. The region from north Pacific to the SRB is covered by anomalous south‐
easterly winds during winter under the influence of these anomalous atmospheric circulation. As a result， the
moisture from the sea to the south of Aleutian and the sea to the east of China are transported to the SRB accom‐
panied by anomalous convergent flow in situ， which are favorable for the increasing snowfall over SRB； and
vice versa.
Key words： Songhua River Basin； winter precipitation； atmospheric circulation； sea surface temperature anom‐
alies