Impact of Solar Activity on Correlation between Snow over the Tibetan Plateau and Summer Precipitation in China

Impact of Solar Activity on Correlation between Snow over the Tibetan Plateau and Summer Precipitation in China

SONG Yan¹，LI Zhicai²，XIAO Ziniu³

（1.Training Centre, China Meteorological Administration, Beijing 100081, China;

2. Shanxi Climate Centre, Taiyuan 030006, China
3. Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029,China)

Abstract So far, the researches about impact of solar activity on snow over the Tibetan Plateau and correlation between snow and precipitation in rainy season of China is empty. This paper used three data sets of solar activity including solar radiation flux (SRF), sunspot number (SSN) and total solar irradiance (TSI) data, snow data from 51 gauge stations over the Tibetan Plateau in China, NCEP/NCAR reanalysis data and precipitation data from 160 rain gauge stations over China to study response of different plateau snow parameters to solar activity on multi-time scales, and modulation of solar activity on correlations between plateau snow and China precipitation in rainy season. It is found that the number of spring snow days is the most sensitive factor of response to the sun. The cross wavelet transform analysis, wavelet coherence and 21-yr running mean show that the correlation coefficients between SRF and snow depth in winter and spring have an obvious change around 1985. Before 1985 the correlations are positive and after 1985 the correlations became negative. However, all of correlations between SRF and numbers of snow days in winter and spring are positive. It indicates that interdecadal correlations between solar activity and numbers of snow days have been stable for several decades. In high and low solar activity years, the correlation pattern between snow and precipitation in rainy season is different significantly. Accordingly, 200hPa atmospheric circulation, 500hPa potential height fields and 200hPa wind fields are different too. Especially after removing years of strong ENSO events, the correlation between snow and precipitation is more significant and stronger, no matter whether the sun is in high or low activity years.

Keywords snow over the Tibetan Plateau, solar activity, precipitation in rainy season of China, correlation on multi-time scales.