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
In this paper, we use pre-column 2 times low-temperature cryo-trap enrichment--gas chromatography（GC） /nitrogen and phosphorus detector（NPD）to detect and analyze phosphine in Arctic pole area for the first time. T...In this paper, we use pre-column 2 times low-temperature cryo-trap enrichment--gas chromatography（GC） /nitrogen and phosphorus detector（NPD）to detect and analyze phosphine in Arctic pole area for the first time. The results show phosphine exists in all of the samples in Arctic pole biosphere and phosphine concentration in Arctic atmosphere is between 18.54- 132.18 ng/m^3, almost the same as that in Antarctic atmosphere; phosphine concentration in Dalian bay sea surface sediments is between 116. 8- 554.3 ng/kg, almost the same as that reported in Jiao-zhou bay. Our research of phosphine will shed new light on the mechanisms showing how the phosphorus supplement influences the biogeochemical cycle and global warming.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 by the National High Technology Research and Development Programme of China ( No. 2008AA09Z114)the Polar Science Research Foundation ( No. 20070214)the Opening Foundation ( No. PCRRF08016) of State Key Laboratory of Pollution Control and Resource Reuse Nanjing University and the National Ocean science Foundation (No. 2008614)
文摘In this paper, we use pre-column 2 times low-temperature cryo-trap enrichment--gas chromatography（GC） /nitrogen and phosphorus detector（NPD）to detect and analyze phosphine in Arctic pole area for the first time. The results show phosphine exists in all of the samples in Arctic pole biosphere and phosphine concentration in Arctic atmosphere is between 18.54- 132.18 ng/m^3, almost the same as that in Antarctic atmosphere; phosphine concentration in Dalian bay sea surface sediments is between 116. 8- 554.3 ng/kg, almost the same as that reported in Jiao-zhou bay. Our research of phosphine will shed new light on the mechanisms showing how the phosphorus supplement influences the biogeochemical cycle and global warming.
