Wednesday, December 12, 2012

New paper finds a decrease in extreme weather in China from 1956-2000

A recent paper published in the Hydrological Sciences Journal examines precipitation in southern China from 1956-2000 and finds precipitation has become both less extreme and less variable. Contrary to claims of climate alarmists, the paper adds to many others demonstrating that global warming decreases extreme weather including extreme precipitation, floods, droughts, and cyclone activity. 

Furthermore, the authors find that the primary determinant of precipitation variability is the Sun, stating, "the annual precipitation in every sub-region in Guangdong province correlates with Sunspot Number with a 3-year lag."

Via the latest NIPCC Report:

Liu, D., Guo, S., Chen, X. and Shao, Q. 2012. Analysis of trends of annual and seasonal precipitation from 1956 to 2000 in Guangdong Province, China. Hydrological Sciences Journal 57: 358-369.

Writing as background for their study, Liu et al. (2012) state that "climate change is consistently associated with changes in a number of components of the hydrological cycle," including "precipitation patterns and intensity, and extreme weather events." Therefore, and in order to "provide advice for water resource management under climate change," they conducted a study of the subject in the Guangdong Province of Southern China, which occupies a land area of approximately 178,000 km2 and has a population of just over 96 million people (as of 2009).

Specifically, Liu et al. analyzed "trends of annual, seasonal and monthly precipitation in southern China (Guangdong Province) for the period 1956-2000 ... based on the data from 186 high-quality gauging stations," and they employed "statistical tests, including the Mann-Kendall rank test and wavelet analysis," in order to determine whether the precipitation series exhibited any regular trends or periodicities.

In describing their findings the four researchers report that "annual precipitation has a slightly decreasing trend in central Guangdong and slight increasing trends in the eastern and western areas of the province," but they say that "all the annual trends are not statistically significant at the 95% confidence level." In addition, they discovered that "average precipitation increases in the dry season in central Guangdong, but decreases in the wet season," such that "precipitation becomes more evenly distributed within the year." Last of all, they state that "the results of wavelet analysis show prominent precipitation with periods ranging from 10 to 12 years in every [italics added] sub-region in Guangdong Province." And comparing precipitation with the 11-year sunspot cycle, they find that "the annual precipitation in every [italics added] sub-region in Guangdong province correlates with Sunspot Number with a 3-year lag."

Rather than becoming more extreme in the face of 1956-2000 global warming, Liu et al.'s analysis of the pertinent data suggest that precipitation in China's Guangdong Province has become both less extreme and less variable. And the temporal precipitation patterns that do emerge upon proper analysis suggest that the primary player in their determination is the sun.

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