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A Half-Century of Precipitation Trends on the North China Plain
Reference
Fan, L., Lu, C., Yang, B. and Chen, Z. 2012. Long-term trends of precipitation in the North China Plain. Journal of Geographic Sciences 22: 989-1001.

Background
In setting the stage for their study, the authors write that "as the most important production area of food grains in China," the North China Plain (NCP) "is suffering from a serious water shortage problem, due to increasing water demand and limited available water resources," which situation could, in their words, "be exacerbated due to climate change, particularly changes in precipitation."

What was done
In an effort designed to determine what may have been happening in this regard over the past half-century, Fan et al. analyzed daily precipitation data from 47 representative stations in the NCP for changes in "the trend and amplitude of variation in monthly, seasonal and annual precipitation, annual maximum continuous no-rain days, annual rain days, rainfall intensity, and rainfall extremes from 1960 to 2007, using the Man-Kendall test and Sen's slope estimator."

What was learned
The four researchers report that "no significant changing trend was found for the annual, dry and wet season precipitation and rainfall extremes in the majority of [the] NCP," with the exception that "the northern part of [the] NCP was becoming wetter in [the] dry season and drier in [the] wet season." And in the case of maximum length of consecutive no-rain days, which they say is "an important drought indicator," they found that "of all the 47 stations, 35 stations showed a significant decreasing trend."

What it means
In the words of the Chinese scientists, "with global warming, seasonal variation of precipitation in [the] NCP tends to be declined ... particularly in the semi-arid/sub-humid northern part." And with less variability in this regard, there are likely to be fewer precipitation extremes throughout this important region. In addition, they state that "as the maximum consecutive no-rain days occurred in [the] dry season, and also in the growing period of winter wheat, the decreasing trend could be a benefit for wheat growth." All in all, therefore, a continuation of these precipitation trends would appear to be a significant positive development for the people of China.

Reviewed 1 May 2013