The spatiotemporal variations of the site and regional droughts in China during 1960–2009 were analyzed by applying a daily composite-drought index （CDI） to 722 stations in China's Mainland. Droughts frequently...The spatiotemporal variations of the site and regional droughts in China during 1960–2009 were analyzed by applying a daily composite-drought index （CDI） to 722 stations in China's Mainland. Droughts frequently happened in a zone extended from Southwest China to the Yellow River, North China, and the southwestern part of Northeast China, with two centers of high frequency in North China and Southwest China. In Southwest and South China, droughts tend to happen during the winter. In North China and along the Yellow River, droughts mainly occur during the winter and during May–June. During the past 50 years, the geographical distribution of site drought events showed high frequencies （0.9–1.3 times per year） in the upper Yellow River basin and North China, comparing with moderate frequencies （0.6–0.9 times per year） in Southwest China and the southwestern part of Northeast China and with lower frequencies over the middle and lower Yangtze River basin. And the frequencies increased over China's Mainland except for the upper reaches of the Yangtze River. A regional drought （RD） event is a widespread and persistent event that covers at least five adjacent sites and lasts for at least 10 days. There were 252 RD events in the past 50 years—five times per year. Most RD events lasted for 100 days and covered 100 stations, but the longest and largest RD event lasted for 307 days from 6 September 1998 to 9 July 1999 and covered 327 stations from North to Southwest China.展开更多
A Based on daily maximum and minimum temperature from Rongcheng station during 1981 -2010, the changing trends of extreme temperature indexes were analyzed. The results show that for the relative indexes, number of w...A Based on daily maximum and minimum temperature from Rongcheng station during 1981 -2010, the changing trends of extreme temperature indexes were analyzed. The results show that for the relative indexes, number of warm days （nights） in Rongcheng station showed an increasing trend, while the number of cold days （nights） showed a decreasing trend from 1981 to 2010, but the decreasing trend of number of cold days was small. For the extreme indexes, the extreme maximum temperature, the maximum of extreme minimum temperature and extreme mini- mum temperature increased, while the minimum of extreme maximum temperature decreased from 1981 to 2010. For the absolute indexes, the numbers of frozen days and frost days reduced, and frozen days were less than frost days for all year.展开更多
基金supported jointly bythe National Natural Science Foundation of China (GrantNo. 40975039)the Key Technologies R&D Program(Grant No. 2009BAC51B04)+1 种基金the Chinese COPES Project (Grant No. GYHY201006018)The CDI data was provided by the Key Technologies R&D Program (GrantNo. 2007BAC29B06).
文摘The spatiotemporal variations of the site and regional droughts in China during 1960–2009 were analyzed by applying a daily composite-drought index （CDI） to 722 stations in China's Mainland. Droughts frequently happened in a zone extended from Southwest China to the Yellow River, North China, and the southwestern part of Northeast China, with two centers of high frequency in North China and Southwest China. In Southwest and South China, droughts tend to happen during the winter. In North China and along the Yellow River, droughts mainly occur during the winter and during May–June. During the past 50 years, the geographical distribution of site drought events showed high frequencies （0.9–1.3 times per year） in the upper Yellow River basin and North China, comparing with moderate frequencies （0.6–0.9 times per year） in Southwest China and the southwestern part of Northeast China and with lower frequencies over the middle and lower Yangtze River basin. And the frequencies increased over China's Mainland except for the upper reaches of the Yangtze River. A regional drought （RD） event is a widespread and persistent event that covers at least five adjacent sites and lasts for at least 10 days. There were 252 RD events in the past 50 years—five times per year. Most RD events lasted for 100 days and covered 100 stations, but the longest and largest RD event lasted for 307 days from 6 September 1998 to 9 July 1999 and covered 327 stations from North to Southwest China.
基金Supported by the Scientific Research Project of Weihai Meteorological Administration in 2013(2013whqxz02)
文摘A Based on daily maximum and minimum temperature from Rongcheng station during 1981 -2010, the changing trends of extreme temperature indexes were analyzed. The results show that for the relative indexes, number of warm days （nights） in Rongcheng station showed an increasing trend, while the number of cold days （nights） showed a decreasing trend from 1981 to 2010, but the decreasing trend of number of cold days was small. For the extreme indexes, the extreme maximum temperature, the maximum of extreme minimum temperature and extreme mini- mum temperature increased, while the minimum of extreme maximum temperature decreased from 1981 to 2010. For the absolute indexes, the numbers of frozen days and frost days reduced, and frozen days were less than frost days for all year.
