The time-mean and interannual variability of the interface between the Indian summer monsoon and East Asian summer monsoon （IIE） was assessed using both Max-Planck-Institute Earth System Model （MPI-ESM） and ECHAM5...The time-mean and interannual variability of the interface between the Indian summer monsoon and East Asian summer monsoon （IIE） was assessed using both Max-Planck-Institute Earth System Model （MPI-ESM） and ECHAM5/MPI-OM and by calculating diagnostics and skill metrics around the IIE area. Progress has been made in modeling these aspects by moving from ECHAM5/MPI-OM to MPI-ESM. MPI-ESM is more skillful than ECHAM5/MPI-OM in modeling the time-mean state and the extreme condition of the IIE. Though simulation of the interannual variability significantly deviates to some extent in both MPI-ESM and ECHAM5/MPI-OM, MPI-ESM-LR shows better skill in reflecting the relationship among sea surface temperature anomalies over the Pacific, circulation anomalies over East Asia, and liE variability. The temperature becomes warmer under the RCP2.6 and RCP8.5 scenarios in comparison with the historical experiments, but the position of the liE and the key physical process in relation to the IIE variability almost remains the same, suggesting that the Indian summer monsoon tends to change in phase with the East Asian summer monsoon under each RCP scenario. The relatively realistic description of the physical processes modulated by terrain in MPI-ESM may be one of the most important reasons why MPI-ESM performs better in simulating the liE.展开更多
基于1958/1959~2009/2010年冬季全球海表温度（HadISST）和中国160站地面月平均温度等资料,利用广义平衡反馈分析方法（GEFA）,分析了中国地区2009/2010年冬季气温异常型态与SST异常的关系。结果表明,热带中东太平洋El Ni o型和热带大...基于1958/1959~2009/2010年冬季全球海表温度（HadISST）和中国160站地面月平均温度等资料,利用广义平衡反馈分析方法（GEFA）,分析了中国地区2009/2010年冬季气温异常型态与SST异常的关系。结果表明,热带中东太平洋El Ni o型和热带大西洋＂三极型＂对2009/2010年冬季中国地区西南暖东北冷的异常型态（简称LN型）影响显著。为了验证统计结果的可靠性,利用MPI（Max Planck Institute for Meteorology）全球大气环流模式ECHAM5进行气温异常型态对关键海盆SST变化响应的敏感性试验,结果表明西南地区气温异常对热带太平洋El Ni o模态强迫的增暖响应在0.5°C左右;对热带大西洋＂三极型＂强迫的增暖响应在0.6°C左右,增暖中心的云贵高原一带最大增温幅度达到1°C。对El Ni o模态、热带大西洋＂三极型＂的强迫,东北绝大部分地区表现出冷的响应,气温异常下降分别在0.6°C和0.45°C左右,中国东部地区气温异常型态是热带大西洋＂三极型＂海温异常和热带太平洋El Ni o模共同强迫的结果。这两种海温异常型态使中高纬度地区西风加强,阻挡了来至高纬度地区的冷空气向南方输送,导致西南地区较常年偏暖,而东北偏冷。同时,西太平洋地区出现的海平面气压反气旋式环流异常可能削弱了东亚冬季风。展开更多
基于美国NOAA现代极高分辨率辐射仪（Advanced Very High Resolution Radiometer）提供的1993—2012年逐日海表温度（SST）资料,利用季节经验正交函数（S-EOF）和相关分析等统计方法,研究了孟加拉湾海表温度变化对南海夏季风爆发的影响...基于美国NOAA现代极高分辨率辐射仪（Advanced Very High Resolution Radiometer）提供的1993—2012年逐日海表温度（SST）资料,利用季节经验正交函数（S-EOF）和相关分析等统计方法,研究了孟加拉湾海表温度变化对南海夏季风爆发的影响。结果表明,孟加拉湾的（6~14°N,85~95°E）海区海表温度变化对南海夏季风爆发早晚具有重要指示意义,该海区海表温度异常（SSTA）与南海夏季风的爆发日期存在密切的正相关,通过了0.05信度的显著性检验,即当孟加拉湾海表温度正（负）异常时,南海夏季风晚（早）爆发。应用德国马普气象研究所的ECHAM5全球大气环流模式在孟加拉湾关键海区进行了敏感性数值试验,发现在关键海区降低其5月海表温度02℃的情况下,南海夏季风爆发日期相应提前5 d左右,而在升高02℃情况下,南海夏季风推后10 d左右爆发。在孟加拉湾5月海表温度降低的情况下,促使80~100°E的越赤道气流增强,南海区域西风分量增强,进而促使南海夏季风提前爆发。展开更多
An ensemble-based assimilation method is proposed for correcting the subsurface temperature field when nudging the sea surface temperature(SST) observations into the Max Planck Institute(MPI) climate model,ECHAM5/MPI-...An ensemble-based assimilation method is proposed for correcting the subsurface temperature field when nudging the sea surface temperature(SST) observations into the Max Planck Institute(MPI) climate model,ECHAM5/MPI-OM. This method can project SST directly to subsurface according to model ensemble-based correlations between SST and subsurface temperature. Results from a 50 year(1960–2009) assimilation experiment show the method can improve the subsurface temperature field up to 300 m compared to the qualitycontrolled subsurface ocean temperature objective analyses(EN4), through reducing the biases of the thermal states, improving the thermocline structure, and reducing the root mean square(RMS) errors. Moreover, as most of the improvements concentrate over the upper 100 m, the ocean heat content in the upper 100 m(OHT100 m)is further adopted as a property to validate the performance of the ensemble-based correction method. The results show that RMS errors of the global OHT100 m convergent to one value after several times iteration,indicating this method can represent the relationship between SST and subsurface temperature fields well, and then improve the accuracy of the simulation in the subsurface temperature of the climate model.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41375097)the Jiangsu Collaborative Innovation Center for Climate Change
文摘The time-mean and interannual variability of the interface between the Indian summer monsoon and East Asian summer monsoon （IIE） was assessed using both Max-Planck-Institute Earth System Model （MPI-ESM） and ECHAM5/MPI-OM and by calculating diagnostics and skill metrics around the IIE area. Progress has been made in modeling these aspects by moving from ECHAM5/MPI-OM to MPI-ESM. MPI-ESM is more skillful than ECHAM5/MPI-OM in modeling the time-mean state and the extreme condition of the IIE. Though simulation of the interannual variability significantly deviates to some extent in both MPI-ESM and ECHAM5/MPI-OM, MPI-ESM-LR shows better skill in reflecting the relationship among sea surface temperature anomalies over the Pacific, circulation anomalies over East Asia, and liE variability. The temperature becomes warmer under the RCP2.6 and RCP8.5 scenarios in comparison with the historical experiments, but the position of the liE and the key physical process in relation to the IIE variability almost remains the same, suggesting that the Indian summer monsoon tends to change in phase with the East Asian summer monsoon under each RCP scenario. The relatively realistic description of the physical processes modulated by terrain in MPI-ESM may be one of the most important reasons why MPI-ESM performs better in simulating the liE.
基金supported by the National Key R&D Programme of China [grant number 2017YFA0604201]the National Natural Science Foundation of China [grant numbers 41576019 and 41876012]
文摘基于1958/1959~2009/2010年冬季全球海表温度（HadISST）和中国160站地面月平均温度等资料,利用广义平衡反馈分析方法（GEFA）,分析了中国地区2009/2010年冬季气温异常型态与SST异常的关系。结果表明,热带中东太平洋El Ni o型和热带大西洋＂三极型＂对2009/2010年冬季中国地区西南暖东北冷的异常型态（简称LN型）影响显著。为了验证统计结果的可靠性,利用MPI（Max Planck Institute for Meteorology）全球大气环流模式ECHAM5进行气温异常型态对关键海盆SST变化响应的敏感性试验,结果表明西南地区气温异常对热带太平洋El Ni o模态强迫的增暖响应在0.5°C左右;对热带大西洋＂三极型＂强迫的增暖响应在0.6°C左右,增暖中心的云贵高原一带最大增温幅度达到1°C。对El Ni o模态、热带大西洋＂三极型＂的强迫,东北绝大部分地区表现出冷的响应,气温异常下降分别在0.6°C和0.45°C左右,中国东部地区气温异常型态是热带大西洋＂三极型＂海温异常和热带太平洋El Ni o模共同强迫的结果。这两种海温异常型态使中高纬度地区西风加强,阻挡了来至高纬度地区的冷空气向南方输送,导致西南地区较常年偏暖,而东北偏冷。同时,西太平洋地区出现的海平面气压反气旋式环流异常可能削弱了东亚冬季风。
文摘基于美国NOAA现代极高分辨率辐射仪（Advanced Very High Resolution Radiometer）提供的1993—2012年逐日海表温度（SST）资料,利用季节经验正交函数（S-EOF）和相关分析等统计方法,研究了孟加拉湾海表温度变化对南海夏季风爆发的影响。结果表明,孟加拉湾的（6~14°N,85~95°E）海区海表温度变化对南海夏季风爆发早晚具有重要指示意义,该海区海表温度异常（SSTA）与南海夏季风的爆发日期存在密切的正相关,通过了0.05信度的显著性检验,即当孟加拉湾海表温度正（负）异常时,南海夏季风晚（早）爆发。应用德国马普气象研究所的ECHAM5全球大气环流模式在孟加拉湾关键海区进行了敏感性数值试验,发现在关键海区降低其5月海表温度02℃的情况下,南海夏季风爆发日期相应提前5 d左右,而在升高02℃情况下,南海夏季风推后10 d左右爆发。在孟加拉湾5月海表温度降低的情况下,促使80~100°E的越赤道气流增强,南海区域西风分量增强,进而促使南海夏季风提前爆发。
基金The National Key R&D Program of China under contract No. 2017YFA0604201the National Natural Science Foundation of China under contract Nos 41876012 and 41861144015.
文摘An ensemble-based assimilation method is proposed for correcting the subsurface temperature field when nudging the sea surface temperature(SST) observations into the Max Planck Institute(MPI) climate model,ECHAM5/MPI-OM. This method can project SST directly to subsurface according to model ensemble-based correlations between SST and subsurface temperature. Results from a 50 year(1960–2009) assimilation experiment show the method can improve the subsurface temperature field up to 300 m compared to the qualitycontrolled subsurface ocean temperature objective analyses(EN4), through reducing the biases of the thermal states, improving the thermocline structure, and reducing the root mean square(RMS) errors. Moreover, as most of the improvements concentrate over the upper 100 m, the ocean heat content in the upper 100 m(OHT100 m)is further adopted as a property to validate the performance of the ensemble-based correction method. The results show that RMS errors of the global OHT100 m convergent to one value after several times iteration,indicating this method can represent the relationship between SST and subsurface temperature fields well, and then improve the accuracy of the simulation in the subsurface temperature of the climate model.
