Shanshan Zhong

Possible association of the western Tibetan Plateau snow cover with the decadal to interdecadal variations of northern China heatwave frequency

Northern China has been subject to increased heatwave frequency (HWF) in recent decades, which deteriorates the local droughts and desertification. More than half a billion people face drinking water shortages and worsening ecological environment. In this study, the variability in the western Tibetan Plateau snow cover (TPSC) is observed to have an intimate linkage with the first empirical orthogonal function mode of the summer HWF across China. This distinct leading mode is dominated by the decadal to inter-decadal variability and features a mono-sign pattern with the extreme value center prevailing over northern China and high pressure anomalies at mid- and upper troposphere over Mongolia and the adjacent regions. A simplified general circulation model is utilized to examine the possible physical mechanism. A reduced TPSC anomaly can induce a positive geopotential height anomaly at the mid- and upper troposphere and subsequently enhance the climatological high pressure ridge over Mongolia and the adjacent regions. The subsidence associated with the high pressure anomalies tends to suppress the local cloud formation, which increases the net radiation budget, heats the surface, and favors more heatwaves. On the other hand, the surface heating can excite high pressure anomalies at mid- and upper troposphere. The latter further strengthens the upper troposphere high pressure anomalies over Mongolia and the adjacent regions. Through such positive feedback effect, the TPSC is tied to the interdecadal variations of the northern China HWF.

The relationships between the zonal temperature variation and ozone distribution in the Northern Hemisphere winter stratosphere

The analysis of photochemical theory and HALOE, SAGE II, ECMWF/ERA-40 data indicate that ozone variations are inversely correlated with temperature in the upper stratosphere, while ozone variations are positively correlated with temperature in the middle stratosphere. Ozone layer mainly locates at middle stratosphere, where solar UV radiation is largely absorbt. The radiation is main action in middle stratosphere, so temperature variation depends on ozone variation. In the upper stratosphere, the ozone concentrations decrease rapidly, the photochemical actions instead of radiation actions play a principal role. The ozone-depleting reaction rates depend on temperature, so the coefficient correlation of Ozone and temperature is reverse.

Seasonal prediction of the typhoon genesis frequency over the Western North Pacific with a Poisson regression model

This study investigates the typhoon genesis frequency (TGF) in the dominant season (July to October) in Western North Pacific (WNP) using observed data in 1965–2015. Of particular interest is the predictability of the TGF and associated preseason sea surface temperature (SST) in the Pacific. It is found that, the TGF is positively related to a tri-polar pattern of April SST anomalies in North Pacific (

The trends of water vapor and methane in the stratosphere in China

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Analysis of the relationship between the precipitation and the SST based on the TRMM data during the Asia monsoon season

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Climatic characteristics of QTP atmospheric heat source in 1961-2001

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