Inhomogeneities in the daily mean/maximum/minimum temperature (T m /T max /T min) series from 1960 2008 at 549 National Standard Stations (NSSs) in China were analyzed by using the Multiple Analysis of Series for Homo...Inhomogeneities in the daily mean/maximum/minimum temperature (T m /T max /T min) series from 1960 2008 at 549 National Standard Stations (NSSs) in China were analyzed by using the Multiple Analysis of Series for Homogenization (MASH) software package.Typical biases in the dataset were illustrated via the cases of Bei-jing (BJ),Wutaishan (WT),ürümqi (UR) and Henan (HN) stations.The homogenized dataset shows a mean warm-ing trend of 0.261/0.193/0.344oC/decade for the annual series of T m /T max /T min,slightly smaller than that of the original dataset by 0.006/0.009/0.007oC/decade.However,considerable differences between the adjusted and origi-nal datasets were found at the local scale.The adjusted T min series shows a significant warming trend almost eve-rywhere for all seasons,while there are a number of sta-tions with an insignificant trend in the original dataset.The adjusted T m data exhibit significant warming trends annually as well as for the autumn and winter seasons in northern China,and cooling trends only for the summer in the middle reaches of the Yangtze River and parts of cen-tral China and for the spring in southwestern China,while the original data show cooling trends at several stations for the annual and seasonal scales in the Qinghai,Shanxi,Hebei,and Xinjiang provinces.The adjusted T max data exhibit cooling trends for summers at a number of stations in the mid-lower reaches of the Yangtze and Yellow Riv-ers and for springs and winters at a few stations in south-western China,while the original data show cooling trends at three/four stations for the annual/autumn periods in the Qinghai and Yunnan provinces.In general,the number of stations with a cooling trend was much smaller in the adjusted T m and T max dataset than in the original dataset.The cooling trend for summers is mainly due to cooling in August.The results of homogenization using MASH appear to be robust;in particular,different groups of stations with consideration of elevation led to minor effects in the results.展开更多
Based on the daily maximum temperature data covering the period 1961-2005, temporal and spatial characteristics and their changing in mean annual and monthly high temperature days（HTDs）and the mean daily maximum tem...Based on the daily maximum temperature data covering the period 1961-2005, temporal and spatial characteristics and their changing in mean annual and monthly high temperature days（HTDs）and the mean daily maximum temperature（MDMT）during annual and monthly HTDs in East China were studied.The results show that the mean annual HTDs were 15.1 and the MDMT during annual HTDs was 36.3℃in the past 45 years.Both the mean annual HTDs and the MDMT during annual HTDs were negative anomaly in the1980s and positive anomaly in the other periods of time,oscillating with a cycle of about 12-15 years.The mean annual HTDs were more in the southern part,but less in the northern part of East China.The MDMT during annual HTDs was higher in Zhejiang,Anhui and Jiangxi provinces in the central and western parts of East China.The high temperature process（HTP） was more in the southwestern part,but less in northeastern part of East China.Both the HTDs and the numbers of HTP were at most in July,and the MDMT during monthly HTDs was also the highest in July.In the first 5 years of the 21st century,the mean annual HTDs and the MDMT during annual HTDs increased at most of the stations,both the mean monthly HTDs and the MDMT during monthly HTDs were positive anomalies from April to October,the number of each type of HTP generally was at most and the MDMT in each type of HTP was also the highest.展开更多
To study the historical temperature variation in Yili of Xinjiang,the tree-ring chronologies of maximum density(MXD) and tree-ring width(TRW) were established with the Schrenk Spruce(Picea schrenkiana Fisch.et Mey) co...To study the historical temperature variation in Yili of Xinjiang,the tree-ring chronologies of maximum density(MXD) and tree-ring width(TRW) were established with the Schrenk Spruce(Picea schrenkiana Fisch.et Mey) collected from six sites to analyze the characteristics and ability of response to climate change.The results suggest that the MXD chronology of the Schrenk Spruce from different sampling sites responded to climate change well and were positively correlated with the mean maximum temperature and the mean temperature from April to August in the study area.The mean maximum temperature anomaly from April to August,spanning the years from 1848 to 2000,was reconstructed by three MXD chronologies which were selected by stepwise regression.The reconstructed function was stable and explained 56.2% of the variance.The reconstructed results indicated a cold span of 153 years in spring and summer from the beginning of the 1950s to the beginning of the 1970s in the Yili valley.No strongly increasing tendency was detected in the mean maximum temperature anomaly from April to August during this reconstructed period.展开更多
Based on tree-ring samples collected from Zaduo area in southern Qinghai Province, a 646-year ring-width series was established. Using response function, correlation function and partial correlation analysis we found ...Based on tree-ring samples collected from Zaduo area in southern Qinghai Province, a 646-year ring-width series was established. Using response function, correlation function and partial correlation analysis we found that the ring-width series is sensitive most to May and June mean maximum air temperature at Zaduo meteorological stations and the correlation is significantly negative. Therefore, May-June mean maximum air temperature in Zaduo area since 1360 is reconstructed using this ring-width series. The regression equation was cross-validated in the calibration period of 1961-2005. The calibration equation can explain 59.8% of the total variance. Since high temperature could reinforce evapotranspiration and result in water stress, the high values are more reliable than the low values in the reconstructed series. By further analyzing upon the reconstructed series, it shows that on the in-ter-annual scale there are 6 periods with higher temperature: 1438-1455, 1572-1612, 1684-1700, 1730-1754, 1812-1829 and 1853-1886; while there are 5 periods with lower temperature: 1547-1571, 1701-1729, 1755-1777, 1830-1852 and 1887-1910. There is no significant rising of temperature in recent 50 years. By comparison with the rings-width series nearby which are also sensitive to the mean maximum air temperature and the mean maximum temperature reconstruction by ring-widths, it is found that the variation of inter-annual scale is fairly common in the region.展开更多
基金supported by the National Basic Research Program of China 2009CB421401 and 2006CB400503
文摘Inhomogeneities in the daily mean/maximum/minimum temperature (T m /T max /T min) series from 1960 2008 at 549 National Standard Stations (NSSs) in China were analyzed by using the Multiple Analysis of Series for Homogenization (MASH) software package.Typical biases in the dataset were illustrated via the cases of Bei-jing (BJ),Wutaishan (WT),ürümqi (UR) and Henan (HN) stations.The homogenized dataset shows a mean warm-ing trend of 0.261/0.193/0.344oC/decade for the annual series of T m /T max /T min,slightly smaller than that of the original dataset by 0.006/0.009/0.007oC/decade.However,considerable differences between the adjusted and origi-nal datasets were found at the local scale.The adjusted T min series shows a significant warming trend almost eve-rywhere for all seasons,while there are a number of sta-tions with an insignificant trend in the original dataset.The adjusted T m data exhibit significant warming trends annually as well as for the autumn and winter seasons in northern China,and cooling trends only for the summer in the middle reaches of the Yangtze River and parts of cen-tral China and for the spring in southwestern China,while the original data show cooling trends at several stations for the annual and seasonal scales in the Qinghai,Shanxi,Hebei,and Xinjiang provinces.The adjusted T max data exhibit cooling trends for summers at a number of stations in the mid-lower reaches of the Yangtze and Yellow Riv-ers and for springs and winters at a few stations in south-western China,while the original data show cooling trends at three/four stations for the annual/autumn periods in the Qinghai and Yunnan provinces.In general,the number of stations with a cooling trend was much smaller in the adjusted T m and T max dataset than in the original dataset.The cooling trend for summers is mainly due to cooling in August.The results of homogenization using MASH appear to be robust;in particular,different groups of stations with consideration of elevation led to minor effects in the results.
基金Funded by R&D Special Fund for Public Welfare Industry(meteorology),No.GYHY(QX)2007-6-19Na-tional Scientific and Technical Supporting Programs,No.2006BAK13B05
文摘Based on the daily maximum temperature data covering the period 1961-2005, temporal and spatial characteristics and their changing in mean annual and monthly high temperature days（HTDs）and the mean daily maximum temperature（MDMT）during annual and monthly HTDs in East China were studied.The results show that the mean annual HTDs were 15.1 and the MDMT during annual HTDs was 36.3℃in the past 45 years.Both the mean annual HTDs and the MDMT during annual HTDs were negative anomaly in the1980s and positive anomaly in the other periods of time,oscillating with a cycle of about 12-15 years.The mean annual HTDs were more in the southern part,but less in the northern part of East China.The MDMT during annual HTDs was higher in Zhejiang,Anhui and Jiangxi provinces in the central and western parts of East China.The high temperature process（HTP） was more in the southwestern part,but less in northeastern part of East China.Both the HTDs and the numbers of HTP were at most in July,and the MDMT during monthly HTDs was also the highest in July.In the first 5 years of the 21st century,the mean annual HTDs and the MDMT during annual HTDs increased at most of the stations,both the mean monthly HTDs and the MDMT during monthly HTDs were positive anomalies from April to October,the number of each type of HTP generally was at most and the MDMT in each type of HTP was also the highest.
基金Supported by the National Basic Research Program of China (Grant No.2009CB421307)Research Foundation of Chinese Desert Meteorology (Grant No.SQJ2006013)National Natural Science Foundation of China (Grant Nos.30270227 and J0630965)
文摘To study the historical temperature variation in Yili of Xinjiang,the tree-ring chronologies of maximum density(MXD) and tree-ring width(TRW) were established with the Schrenk Spruce(Picea schrenkiana Fisch.et Mey) collected from six sites to analyze the characteristics and ability of response to climate change.The results suggest that the MXD chronology of the Schrenk Spruce from different sampling sites responded to climate change well and were positively correlated with the mean maximum temperature and the mean temperature from April to August in the study area.The mean maximum temperature anomaly from April to August,spanning the years from 1848 to 2000,was reconstructed by three MXD chronologies which were selected by stepwise regression.The reconstructed function was stable and explained 56.2% of the variance.The reconstructed results indicated a cold span of 153 years in spring and summer from the beginning of the 1950s to the beginning of the 1970s in the Yili valley.No strongly increasing tendency was detected in the mean maximum temperature anomaly from April to August during this reconstructed period.
基金supported by the National Natural Science Foundation of China (40599424)Sichuan Meteorological Bureau (08-02) and Institute of Plateau Meteorology,China Meteorological Administration (BROP200 810)
文摘Based on tree-ring samples collected from Zaduo area in southern Qinghai Province, a 646-year ring-width series was established. Using response function, correlation function and partial correlation analysis we found that the ring-width series is sensitive most to May and June mean maximum air temperature at Zaduo meteorological stations and the correlation is significantly negative. Therefore, May-June mean maximum air temperature in Zaduo area since 1360 is reconstructed using this ring-width series. The regression equation was cross-validated in the calibration period of 1961-2005. The calibration equation can explain 59.8% of the total variance. Since high temperature could reinforce evapotranspiration and result in water stress, the high values are more reliable than the low values in the reconstructed series. By further analyzing upon the reconstructed series, it shows that on the in-ter-annual scale there are 6 periods with higher temperature: 1438-1455, 1572-1612, 1684-1700, 1730-1754, 1812-1829 and 1853-1886; while there are 5 periods with lower temperature: 1547-1571, 1701-1729, 1755-1777, 1830-1852 and 1887-1910. There is no significant rising of temperature in recent 50 years. By comparison with the rings-width series nearby which are also sensitive to the mean maximum air temperature and the mean maximum temperature reconstruction by ring-widths, it is found that the variation of inter-annual scale is fairly common in the region.
