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 analyze...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 （Tmax） and daily minimum temperature （Tmin） are greater than the 90th percentile and less than thel0th percentile,respectively.Generally,the trend magnitudes are larger in indices derived from Tmin than those from Tmax.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 westem 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 southem 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.展开更多
This paper demonstrates regional characteristics, a long-term decreasing trend, and decadal variations in the frequency of cold surge events based on daily mean temperature and daily minimum temperature data in China&...This paper demonstrates regional characteristics, a long-term decreasing trend, and decadal variations in the frequency of cold surge events based on daily mean temperature and daily minimum temperature data in China's Mainland from 1960 to 2008. During these 48 years four high frequency centers of cold surge events were located in Xinjiang, central North China, northeast China, and southeast China. A main frequency peak of cold surge events occurs in autumn for the four regions and another peak is detected in spring over northeast China and southeast China. The regional pattern of cold surge frequencies is in accordance with the perturbation kinetic energy distribution in October December, January, and February April. The long-term decreasing trend ( 0.2 times/decade) of cold surge frequencies in northeast China and decadal variations in China are related to the variations of the temperature difference between southern and northern China in the winter monsoon season; these variations are due to the significant rising of winter temperatures in high latitudes.展开更多
基金supported by the Department of Science and Technology of China(2009CB421403 and2010CB428403)by the National Natural Science Foundation of China(41275110)
文摘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 （Tmax） and daily minimum temperature （Tmin） are greater than the 90th percentile and less than thel0th percentile,respectively.Generally,the trend magnitudes are larger in indices derived from Tmin than those from Tmax.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 westem 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 southem 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.
基金supported jointly by the National Natural Science Foundation of China (40975039)the National Basic Research Program of China (2006CB400504/ 2009CB421401 and GYHY20070605)
文摘This paper demonstrates regional characteristics, a long-term decreasing trend, and decadal variations in the frequency of cold surge events based on daily mean temperature and daily minimum temperature data in China's Mainland from 1960 to 2008. During these 48 years four high frequency centers of cold surge events were located in Xinjiang, central North China, northeast China, and southeast China. A main frequency peak of cold surge events occurs in autumn for the four regions and another peak is detected in spring over northeast China and southeast China. The regional pattern of cold surge frequencies is in accordance with the perturbation kinetic energy distribution in October December, January, and February April. The long-term decreasing trend ( 0.2 times/decade) of cold surge frequencies in northeast China and decadal variations in China are related to the variations of the temperature difference between southern and northern China in the winter monsoon season; these variations are due to the significant rising of winter temperatures in high latitudes.
