Title: Variety of Ningxia Cold Waves in the Last 48 Years and Its Possible Reasons
Abstract: By using the daily surface temperature data of Ningxia,monthly characteristic values of 500 hPa circulation of the Northern Hemisphere,Arctic Oscillation Index(AOI) and NCEP/NCAR reanalyzed data during 1961-2008,the climatic characteristics of the variety of cold waves in Ningxia are analyzed,and the possible reasons for it are further discussed.The result indicates:the cold wave activities are distinct different in Ningxia different regions,and mainly occur in spring;in the recent 48 years,cold waves in Ningxia increased slightly in spring and autumn,decreased slightly in winter;the frequency of cold waves in Ningxia has negative correlation with AOI and temperature,positive correlation with the intensity of Siberian high,East Asian winter monsoon and the frequency of cold air activities invaded China,and the correlativity is obvious in autumn,winter and inconspicuous in spring;under the background of global warming,with the phase of AOI transformed from negative into positive from the end of 1980s,the intensity of winter Siberian high and East Asian winter monsoon has weakened,and made the surface temperature continue rising in Ningxia,this is one of the possible reasons for the decrease of Ningxia cold waves in winter;in spring,there has the similar variety but differs in the following points:the Siberian high played a more significant role in cold wave activities before the mid-1980s,while the impact of cold air activities on cold waves was more obvious with the continuou temperature rising after then;meanwhile,the Siberian high and the cold air activities impacted the cold waves more directly and more obviously in autumn.Studies also found,that with continued global warming,the impact of Arctic Oscillation on Siberian high and East Asian winter monsoon has weakened after the 21st century.Therefore,the mutual feedback among the Arctic Oscillation,Siberian high,the frequency of cold air activities,the East Asian winter monsoon and temperature is the possible reason for the variety of Ningxia cold wave frequency.
Publication Year: 2010
Publication Date: 2010-01-01
Language: en
Type: article
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Cited By Count: 4
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