基于NCEP-GEFS回算资料的我国极端温度变化特征研究
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摘要
利用美国NCEP全球集合预报系统(GEFS)历史回算资料和中国均一化格点观测数据,分析了我国近30 a来极端温度变化特征,重点考察了该模式预报系统对这一变化特征的刻画性能。通过估算格点观测和模式资料中2 m温度的历史气候百分位,分析了我国冬夏两季极端温度的气候特征以及极端温度日数的气候分布和多年变化趋势。结果表明,我国冬季极端低温和夏季极端高温的空间分布表现出较强区域性特征:东北、华北和青藏高原区域冬季极端低温的百分位阈值对应的温度较低,而华南、西北和长江流域夏季极端高温的阈值温度则较高;近30 a来我国夏季平均温度和极端高温日数几乎都呈现上升趋势,冬季平均温度则在我国大部分区域呈上升趋势、西北和东北部分地区呈下降趋势,相应地冬季极端低温日数在大部分区域呈下降趋势、仅在西北、东北和华南部分地区略有上升。NCEP-GEFS回算资料能较好地再现我国冬夏两季平均气温、冬季极端低温和夏季极端高温日数的气候趋势和年际变化,但在各区域都有不同程度的冷偏差,冬季偏差明显大于夏季,并随着预报时长的增加,冬季冷偏差逐渐增强,而夏季冷偏差则逐渐减弱。因此,本文建议采用基于百分位阈值的相对极端性定义,可自动修正模式分析场和预报场中的系统性偏差。
In this study,based on the reforecast data of NCEP Global Ensemble Forecast System( GEFS) and China homogeneous grid-point observational data,features of extreme temperature variations in the past 30 years are analyzed,a nd the performance of the NCEP-GEFS in representing these kinds of features is thoroughly investigated.By estimating the historical climatic percentile of 2 m temperature in the observational and model data, the characteristics of extreme temperature in winter and summer,along with the spatial distribution and multi-year trend of extreme temperature days,are analyzed.The results show that some strong regional features exist in the spatial distributions of winter extreme low temperature( ELT) and summer extreme high temperature( EHT) in China,i.e.there are relatively lower temperatures corresponding to the percentile thresholds of the winter ELT in northeastern China,northern China and the Qinghai-Tibet Plateau,with higher temperatures corresponding to the percentile thresholds of the summer EHT in southern China,northwestern China and the Yangtze River Basin.Both the summer mean temperature and EHT days throughout China show increasing trends in the past 30 years,and the winter mean temperatures are also increasing throughout most of China,y et decreasing in northwestern and northeastern China.Correspondingly, the numbers of days of the winter ELT are decreasing in most areas,and only slightly increasing in small parts of northwestern,northeastern and southern China.The NCEP-GEFS reforecasts are able to accurately reproduce the climatic trends and interannual variations of the seasonal mean temperature and extreme temperature days in the winter and summer of China,y et varying degrees of cold biases exist in the different regions.The biases in winter are significantly larger than those in summer,and as the forecast length increases, these cold biases are gradually strengthened in winter,while gradually weakened in summer.Therefore, it is suggested to adopt the relative definition of extreme temperature based on the percentile threshold,which can automatically correct these systematic biases in the model analysis and prediction products.
In this study,based on the reforecast data of NCEP Global Ensemble Forecast System( GEFS) and China homogeneous grid-point observational data,features of extreme temperature variations in the past 30 years are analyzed,a nd the performance of the NCEP-GEFS in representing these kinds of features is thoroughly investigated.By estimating the historical climatic percentile of 2 m temperature in the observational and model data, the characteristics of extreme temperature in winter and summer,along with the spatial distribution and multi-year trend of extreme temperature days,are analyzed.The results show that some strong regional features exist in the spatial distributions of winter extreme low temperature( ELT) and summer extreme high temperature( EHT) in China,i.e.there are relatively lower temperatures corresponding to the percentile thresholds of the winter ELT in northeastern China,northern China and the Qinghai-Tibet Plateau,with higher temperatures corresponding to the percentile thresholds of the summer EHT in southern China,northwestern China and the Yangtze River Basin.Both the summer mean temperature and EHT days throughout China show increasing trends in the past 30 years,and the winter mean temperatures are also increasing throughout most of China,y et decreasing in northwestern and northeastern China.Correspondingly, the numbers of days of the winter ELT are decreasing in most areas,and only slightly increasing in small parts of northwestern,northeastern and southern China.The NCEP-GEFS reforecasts are able to accurately reproduce the climatic trends and interannual variations of the seasonal mean temperature and extreme temperature days in the winter and summer of China,y et varying degrees of cold biases exist in the different regions.The biases in winter are significantly larger than those in summer,and as the forecast length increases, these cold biases are gradually strengthened in winter,while gradually weakened in summer.Therefore, it is suggested to adopt the relative definition of extreme temperature based on the percentile threshold,which can automatically correct these systematic biases in the model analysis and prediction products.
引文
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Easterling D R,Evans J L,Groisman P Y,et al.,2000.Observed variability and trends in extreme climate events:a brief review[J].Bull Amer Meteor Soc,81(3):417-425.
龚志强,王晓娟,支蓉,等,2009.中国近58年温度极端事件的区域特征及其与气候突变的联系[J].物理学报,58(6):4342-4353.Gong Z Q,Wang X J,Zhi R,et al.,2009.Regional characteristics of temperature changes in China during the past 58 years and its probable correlation with abrupt temperature change[J].Acta Physica Sinica,58(6):4342-4353.(in Chinese).
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皇甫雪官,2002.国家气象中心集合数值预报检验评价[J].应用气象学报,13(1):29-36.Huangpu X G,2002.The verification for ensemble prediction system of national meteorological center[J].J Appl Meteor Sci, 13(1):29-36.(in Chinese).
刘学华,季致建,吴洪宝,等, 2006.中国近40年极端气温和降水的分布特征及年代际差异[J].热带气象学报,22 (6):618-624. Liu X H, Ji Z J,Wu H B, et al., 2006.Distributing characteristics and interdecadal difference of daily temperature and precipitation extremes in China for latest 40years[J].J Trop Meteor,22(6):618-624.(in Chinese).
罗亚丽, 2012.极端天气和气候事件的变化[J].气候变化研究进展,8(2):90-98. Luo Y L,2012.Changes in weather and climate extremes[J].Advances in Climate Change Research,8(2):90-98.(in Chinese).
Meehl G A,Karl T,Easterling D R, et al.,2000.An introduction to trends in extreme weather and climate events:observations, socioeconomic impacts,terrestrial ecological impacts, and model projections[J].Bull Amer Meteor Soc, 81(3):413-416.
Palmer T N,Brankovi c'C,Richardson D S, 2010.A probability and decision-model analysis of PROVOST seasonal multi-model ensemble integrations[J].Quart J Roy Meteor Soc, 126(567):2013-2033.
彭勇,王萍,徐炜,等, 2012.气象集合预报的研究进展[J].南水北调与水利科技, 10(4):90-96,126 . Peng Y,Wang P,Xu W, et al.,2012.Review of weather ensemble prediction[J].South-to-North Water Transfers and Water Science&Technology,10(4):90-96,126 .(in Chinese).
任晨辰,段明铿,智协飞,2017 .不同气候背景下我国冬夏两季极端气温特征分析[J].大气科学学报,40(6):803-813. Ren C C,Duan M K,Zhi X F, 2017.Characteristics of extreme surface air temperature in winter and summer over China under different climate backgrounds[J].Trans Atmos Sci, 40(6):803-813.(in Chinese).
任福民,翟盘茂, 1998. 1951—1990年中国极端气温变化分析[J].大气科学,22(2):217-226. Ren F M,Zhai P M,1998. Study on changes of China's extreme temperatures during 1951—1990[J].Chin J Atmos Sci,22(2):217-226.(in Chinese).
Richardson D,2000.Skill and relative economic value of the ECMWF ensemble prediction system[J].Quart J Roy Meteor Soc,126(563):649-667.
Solomon S,Qin D,Manning M, et al.,2007.Climate change 2007:the physical science basis[R]//Contribution of working group 1 to the fourth report of the intergovernmental panel on climate change.Cambridge,United Kingdom and New York:Cambridge University Press.
唐红玉,翟盘茂, 2003.中国北方春季沙尘暴与北半球500 hPa高度场的SVD分析(摘要)[C]//2003中国气象学会年会. Tang H Y,Zhai P M, 2003.SVD analysis between Northern Hemisphere 500 hPa heights and spring duststorms over northern China(abstract)[C]//2003 Chinese Meteorological Society.(in Chinese).
van den Dool H M,Toth Z, 1991.Why do forecasts for“near normal”often fail?[J].Wea Forecasting,6(1):76-5.
杨萍,刘伟东,王启光,等, 2010.近40年我国极端温度变化趋势和季节特征[J].应用气象学报,21(1)29-36. Yang P,Liu W D,Wang Q G, et al., 2010.The climatic change trend and seasonal characteristics of daily temperature extremes in China for the latest 40 years[J].J Appl Meteor Sci, 21(1):29-36.(in Chinese).
翟盘茂,潘晓华, 2003.中国北方近50年温度和降水极端事件变化[J].地理学报,58 (S):1-10. Zhai P M,Pan X H,2003.Change in extreme temperature and precipitation over northern China during the second half of the 20th century[J].Acta Geographica Sinica, 58(S):1-10.(in Chinese).
张涵斌,智协飞,陈静,等, 2017.区域集合预报扰动方法研究进展综述[J].大气科学学报,40(2):145-157. Zhang H B,Zhi X F,Chen J, et al.,2017.Achievement of perturbation methods for regional ensemble forecast[J].Trans Atmos Sci,40(2):145-157.(in Chinese).
杜钧,2002.集合预报的现状和前景[J].应用气象学报,13(1):16-28.Du J,2002.Present situation and prospects of ensemble numerical prediction[J].J Appl Meteor Sci,13(1):16-28.(in Chinese).
Easterling D R,Evans J L,Groisman P Y,et al.,2000.Observed variability and trends in extreme climate events:a brief review[J].Bull Amer Meteor Soc,81(3):417-425.
龚志强,王晓娟,支蓉,等,2009.中国近58年温度极端事件的区域特征及其与气候突变的联系[J].物理学报,58(6):4342-4353.Gong Z Q,Wang X J,Zhi R,et al.,2009.Regional characteristics of temperature changes in China during the past 58 years and its probable correlation with abrupt temperature change[J].Acta Physica Sinica,58(6):4342-4353.(in Chinese).
HoughtonJ T,Ding Y,Griggs D J,et al.,2001.Climate change 2001:the science of climate change[R]//Contribution of working group 1 to the third assessment report of the intergovernmental panel on climate change.Cambridge,United Kingdom and New York:Cambridge University Press.
皇甫雪官,2002.国家气象中心集合数值预报检验评价[J].应用气象学报,13(1):29-36.Huangpu X G,2002.The verification for ensemble prediction system of national meteorological center[J].J Appl Meteor Sci, 13(1):29-36.(in Chinese).
刘学华,季致建,吴洪宝,等, 2006.中国近40年极端气温和降水的分布特征及年代际差异[J].热带气象学报,22 (6):618-624. Liu X H, Ji Z J,Wu H B, et al., 2006.Distributing characteristics and interdecadal difference of daily temperature and precipitation extremes in China for latest 40years[J].J Trop Meteor,22(6):618-624.(in Chinese).
罗亚丽, 2012.极端天气和气候事件的变化[J].气候变化研究进展,8(2):90-98. Luo Y L,2012.Changes in weather and climate extremes[J].Advances in Climate Change Research,8(2):90-98.(in Chinese).
Meehl G A,Karl T,Easterling D R, et al.,2000.An introduction to trends in extreme weather and climate events:observations, socioeconomic impacts,terrestrial ecological impacts, and model projections[J].Bull Amer Meteor Soc, 81(3):413-416.
Palmer T N,Brankovi c'C,Richardson D S, 2010.A probability and decision-model analysis of PROVOST seasonal multi-model ensemble integrations[J].Quart J Roy Meteor Soc, 126(567):2013-2033.
彭勇,王萍,徐炜,等, 2012.气象集合预报的研究进展[J].南水北调与水利科技, 10(4):90-96,126 . Peng Y,Wang P,Xu W, et al.,2012.Review of weather ensemble prediction[J].South-to-North Water Transfers and Water Science&Technology,10(4):90-96,126 .(in Chinese).
任晨辰,段明铿,智协飞,2017 .不同气候背景下我国冬夏两季极端气温特征分析[J].大气科学学报,40(6):803-813. Ren C C,Duan M K,Zhi X F, 2017.Characteristics of extreme surface air temperature in winter and summer over China under different climate backgrounds[J].Trans Atmos Sci, 40(6):803-813.(in Chinese).
任福民,翟盘茂, 1998. 1951—1990年中国极端气温变化分析[J].大气科学,22(2):217-226. Ren F M,Zhai P M,1998. Study on changes of China's extreme temperatures during 1951—1990[J].Chin J Atmos Sci,22(2):217-226.(in Chinese).
Richardson D,2000.Skill and relative economic value of the ECMWF ensemble prediction system[J].Quart J Roy Meteor Soc,126(563):649-667.
Solomon S,Qin D,Manning M, et al.,2007.Climate change 2007:the physical science basis[R]//Contribution of working group 1 to the fourth report of the intergovernmental panel on climate change.Cambridge,United Kingdom and New York:Cambridge University Press.
唐红玉,翟盘茂, 2003.中国北方春季沙尘暴与北半球500 hPa高度场的SVD分析(摘要)[C]//2003中国气象学会年会. Tang H Y,Zhai P M, 2003.SVD analysis between Northern Hemisphere 500 hPa heights and spring duststorms over northern China(abstract)[C]//2003 Chinese Meteorological Society.(in Chinese).
van den Dool H M,Toth Z, 1991.Why do forecasts for“near normal”often fail?[J].Wea Forecasting,6(1):76-5.
杨萍,刘伟东,王启光,等, 2010.近40年我国极端温度变化趋势和季节特征[J].应用气象学报,21(1)29-36. Yang P,Liu W D,Wang Q G, et al., 2010.The climatic change trend and seasonal characteristics of daily temperature extremes in China for the latest 40 years[J].J Appl Meteor Sci, 21(1):29-36.(in Chinese).
翟盘茂,潘晓华, 2003.中国北方近50年温度和降水极端事件变化[J].地理学报,58 (S):1-10. Zhai P M,Pan X H,2003.Change in extreme temperature and precipitation over northern China during the second half of the 20th century[J].Acta Geographica Sinica, 58(S):1-10.(in Chinese).
张涵斌,智协飞,陈静,等, 2017.区域集合预报扰动方法研究进展综述[J].大气科学学报,40(2):145-157. Zhang H B,Zhi X F,Chen J, et al.,2017.Achievement of perturbation methods for regional ensemble forecast[J].Trans Atmos Sci,40(2):145-157.(in Chinese).