The Circulation Anomalies of the Winter Persistent Regional Haze Events in Shaanxi Province and Their Precursor Signal
Online published: 2024-09-19
Based on daily observations from ground-level stations and daily NCEP/NCAR reanalysis dataset,the circulation anomalies of the winter persistent regional haze events for the years 1980-2021 in Guanzhong region of Shaanxi and their precursor signal are analyzed. The winter persistent regional haze events in Guanzhong region is found to be closely connected with a pronounced atmospheric teleconnection pattern from the North Atlantic to Euraisa. A positive North Atlantic Osciilation(NAO+)phase and a positive East Atlantic/West Russia(EA/ WR+)phase are observed as important part of this teleconnection pattern,the NAO+ pattern act as the origin of the atmospheric transmission. Approximately 75% of the NAO positive phase days from 15 to 5 days before the occurrence of persistent regional haze events are greater than 5 days,with a daily NAO index greater than or close to 0 and an average intensity greater than 0. There is a clear EATL/WRUS+ pattern in the Eurasian continent at 500 hPa three days prior to and after the occurrence day of persistent regional haze events in Guanzhong during winter. On the 1ST to 6th day,a clear positive geopotential height anomaly extends from Northeast China to the Sea of Japan at 850 hPa,which reflects the positive anomaly pressure gradient from the Korean Peninsula to central China accompanied with stronger southeast wind in Guanzhong. The stronger southeast wind anomaly intensifies the convergence in Guanzhong region and Southern Shaanxi,and transport the aerosol from central and eastern China to Shaanxi Province.
HUANG Xin, HE Yin, PAN Liujie, DONG Zipeng, LIU Hui, HE Huibo, DANGRui, REN Qi . The Circulation Anomalies of the Winter Persistent Regional Haze Events in Shaanxi Province and Their Precursor Signal[J]. Plateau Meteorology, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2024.00087
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