Changes in Daily Climate Extremes of Observed Temperature and Precipitation in China

Daily precipitation for 1960-2011 and maximum/minimum temperature extremes for 1960-2008 recorded at 549 stations in China are utilized to investigate climate extreme variations. A set of indices is derived and analyzed with a main focus on the trends and variabilities of daily extreme occurrences. Results show significant increases in daily extreme warm temperatures and decreases in daily extreme cold temperatures, defined as the number of days in which daily maximum temperature (T-max) and daily minimum temperature (T-min) are greater than the 90th percentile and less than the 10th percentile, respectively. Generally, the trend magnitudes are larger in indices derived from T-min than those from T-max. Trends of percentile-based precipitation indices show distinct spatial patterns with increases in heavy precipitation events, defined as the top 95th percentile of daily precipitation, in western and northeastern China and in the low reaches of the Yangtze River basin region, and slight decreases in other areas. Light precipitation, defined as the tail of the 5th percentile of daily precipitation, however, decreases in most areas. The annual maximum consecutive dry days (CDD) show an increasing trend in southern China and the middle-low reach of the Yellow River basin, while the annual maximum consecutive wet days (CWD) displays a downtrend over most regions except western China. These indices vary significantly with regions and seasons. Overall, occurrences of extreme events in China are more frequent, particularly the night time extreme temperature, and landmasses in China become warmer and wetter.