Land surface temperature(LST)is one of the most important factors in the land-atmosphere interaction process.Raw measured LSTs may contain biases due to instrument replacement,changes in recording procedures,and other...Land surface temperature(LST)is one of the most important factors in the land-atmosphere interaction process.Raw measured LSTs may contain biases due to instrument replacement,changes in recording procedures,and other non-climatic factors.This study attempts to reduce the above biases in raw daily measurements and achieves a homogenized daily LST dataset over China using 2360 stations from 1960 through 2017.The high-quality land surface air temperature(LSAT)dataset is used to correct the LST warming biases especially evident during cold months in regions north of 40ºN due to the replacement of observation instruments around 2004.Subsequently,the Multiple Analysis of Series for Homogenization(MASH)method is adopted to detect and then adjust the daily observed LST records.In total,3.68×10^(3) effective breakpoints in 1.65×106 monthly records(about 20%)are detected.A large number of these effective breakpoints are located over large parts of the Sichuan Basin and southern China.After the MASH procedure,LSTs at more than 80%of the breakpoints are adjusted within+/-0.5℃,and of the remaining breakpoints,only 10%are adjusted over 1.5℃.Compared to the raw LST dataset over the whole domain,the homogenization significantly reduces the mean LST magnitude and its interannual variability as well as its linear trend at most stations.Finally,we perform preliminary analysis upon the homogenized LST and find that the annual mean LST averaged across China shows a significant warming trend[0.22℃(10 yr)^(-1)].The homogenized LST dataset can be further adapted for a variety of applications(e.g.,model evaluation and extreme event characterization).展开更多
海表温度是重要的环境特征指标。为了实时高精度测量海表皮温,中国海洋大学研制了一台海表测温辐射测量系统(The First Infrared Radiometer for measurements of Skin SST made by Ocean University of China,OUCFIRST,简称FIRST系统)...海表温度是重要的环境特征指标。为了实时高精度测量海表皮温,中国海洋大学研制了一台海表测温辐射测量系统(The First Infrared Radiometer for measurements of Skin SST made by Ocean University of China,OUCFIRST,简称FIRST系统)。FIRST系统使用热释电辐射传感器,测量海表、天空和内部标准黑体的辐射量,对测量的海表辐射进行实时校正,得到精确的海表辐射值,通过反演计算,得到高精度海表皮温。FIRST系统内部使用了可溯源的测温仪,可测量标准黑体温度,该系统采用了自容式设计,测温精度高且部署容易。FIRST系统参加了2016年在英国国家物理实验室(National Physical Laboratory)NPL进行的联合观测实验,在实验室测量了标准黑体,在室外湖面进行了实测,测量结果优于33mK,测量准确度位列各参测仪器的第二名。实验结果表明,FIRST系统具有较好的测量精度,可用于海表皮温的高精度测量。展开更多
基金This work was supported by the National Science Fund for Distinguished Young Scholars(Grant No.41925021)the National Natural Science Foundation of China(Grant No.41875106).
文摘Land surface temperature(LST)is one of the most important factors in the land-atmosphere interaction process.Raw measured LSTs may contain biases due to instrument replacement,changes in recording procedures,and other non-climatic factors.This study attempts to reduce the above biases in raw daily measurements and achieves a homogenized daily LST dataset over China using 2360 stations from 1960 through 2017.The high-quality land surface air temperature(LSAT)dataset is used to correct the LST warming biases especially evident during cold months in regions north of 40ºN due to the replacement of observation instruments around 2004.Subsequently,the Multiple Analysis of Series for Homogenization(MASH)method is adopted to detect and then adjust the daily observed LST records.In total,3.68×10^(3) effective breakpoints in 1.65×106 monthly records(about 20%)are detected.A large number of these effective breakpoints are located over large parts of the Sichuan Basin and southern China.After the MASH procedure,LSTs at more than 80%of the breakpoints are adjusted within+/-0.5℃,and of the remaining breakpoints,only 10%are adjusted over 1.5℃.Compared to the raw LST dataset over the whole domain,the homogenization significantly reduces the mean LST magnitude and its interannual variability as well as its linear trend at most stations.Finally,we perform preliminary analysis upon the homogenized LST and find that the annual mean LST averaged across China shows a significant warming trend[0.22℃(10 yr)^(-1)].The homogenized LST dataset can be further adapted for a variety of applications(e.g.,model evaluation and extreme event characterization).
文摘海表温度是重要的环境特征指标。为了实时高精度测量海表皮温,中国海洋大学研制了一台海表测温辐射测量系统(The First Infrared Radiometer for measurements of Skin SST made by Ocean University of China,OUCFIRST,简称FIRST系统)。FIRST系统使用热释电辐射传感器,测量海表、天空和内部标准黑体的辐射量,对测量的海表辐射进行实时校正,得到精确的海表辐射值,通过反演计算,得到高精度海表皮温。FIRST系统内部使用了可溯源的测温仪,可测量标准黑体温度,该系统采用了自容式设计,测温精度高且部署容易。FIRST系统参加了2016年在英国国家物理实验室(National Physical Laboratory)NPL进行的联合观测实验,在实验室测量了标准黑体,在室外湖面进行了实测,测量结果优于33mK,测量准确度位列各参测仪器的第二名。实验结果表明,FIRST系统具有较好的测量精度,可用于海表皮温的高精度测量。
