中国覆盖比较完整的台站观测始于1951年，1951年之前虽然有一些观测记录，但是残缺不全。所以要建立更长的气候序列就要吸收代用资料，但是代用资料可能与气候要素仅有一定程度的相关，不可能一一对应，因此应用代用资料重建的气候序列...中国覆盖比较完整的台站观测始于1951年，1951年之前虽然有一些观测记录，但是残缺不全。所以要建立更长的气候序列就要吸收代用资料，但是代用资料可能与气候要素仅有一定程度的相关，不可能一一对应，因此应用代用资料重建的气候序列有一定的不确定性。英国East Anglia大学的Climatic Research Unit（简称CRU）通过整合已有的若干个知名数据库，重建了一套覆盖完整、高分辨率、且无缺测的月平均地表气候要素数据集，时间范围覆盖1901-2003年，空间为0．5°×0．5°经纬网格覆盖所有陆地。这套资料和中国已有的气候数据相比具有如下优点：第一，中国西部20世纪前半期非常缺少观测，CRU资料尽管包含插值带来的误差，经比较仍可作为有一定信度的参考；第二，中国现有的百年温度序列只是年或季分辨率，而CRU资料达到月分辨率；第三，建立这个序列仅使用观测结果，做统计内插，不包括代用资料所带来的不确定性。因此，CRU的序列与用代用资料补充得到的序列在资料方面有较大不同，比较这两个序列，不仅可以进一步确认中国气候变化的特征，也可以彼此校正。结果表明：（1）CRU资料反映的全国年平均温度年际变化和考虑代用资料重建的序列吻合得很好，相关系数达到0．84；（2）区域尺度上，两者在10个典型分区的气温变率也相当一致，相关整体保持在0．8左右，仅新疆西南部和西藏西北部两者差异较大；（3）CRU资料揭示的中国年总降水量在1951～2000年的变化与160站观测吻合，相关系数达到0．93；（4）CRU资料的中国东部四季降水量和重建资料十分一致，秋季一致性最好，相关0．93；（5）CRU资料和重建的序列比较一致地表现出中国温度和降水年代际变化的主要特征，其给出的20世纪20年代中国大旱和20世纪40年代中国高温的空间�展开更多
Through the use of reliable AMS dating of high resolution (15-30 years) peat and the establishment of monsoon climate proxies sequence, we have been able to recognize several cold, dry events in the Tibetan Plateau du...Through the use of reliable AMS dating of high resolution (15-30 years) peat and the establishment of monsoon climate proxies sequence, we have been able to recognize several cold, dry events in the Tibetan Plateau during the Holocene. The more obvious ones occurred around 12800, 11300, 10200, 9580, 8900, 6400, 4400, 3700, 2800 and 1500 cal. aBP. These events correlate well with both ice rafting events recorded in high latitude North Atlantic Ocean sediment cores and cooling events in the low latitude SST. Spectral analysis indicates high frequency climate variation on centennial-millennial time scale during the Holocene. This further reflects Holocene climate instability and the existence of centennial-millenium scale rhythm in mid latitude areas as well.展开更多
Soil moisture plays an important role in land-atmosphere interactions. It is an important geophysical parameter in research on climate, hydrology, agriculture, and forestry. Soil moisture has important climatic effect...Soil moisture plays an important role in land-atmosphere interactions. It is an important geophysical parameter in research on climate, hydrology, agriculture, and forestry. Soil moisture has important climatic effects by influencing ground evapotranspi ration, runoff, surface reflectivity, surface emissivity, surface sensible heat and latent heat flux. At the global scale, the extent of its influence on the atmosphere is second only to that of sea surface temperature. At the terrestrial scale, its influence is even greater than that of sea surface temperatures. This paper presents a China Land Soil Moisture Data Assimilation System (CLSMDAS) based on EnKF and land process models, and results of the application of this system in the China Land Soil Moisture Data Assimilation tests. CLSMDAS is comprised of the following components: 1) A land process mo del—Community Land Model Version 3.0 (CLM3.0)—developed by the US National Center for Atmospheric Research (NCAR); 2) Precipitation of atmospheric forcing data and surface-incident solar radiation data come from hourly outputs of the FY2 geostationary meteorological satellite; 3) EnKF (Ensemble Kalman Filter) land data assimilation method; and 4) Observa tion data including satellite-inverted soil moisture outputs of the AMSR-E satellite and soil moisture observation data. Results of soil moisture assimilation tests from June to September 2006 were analyzed with CLSMDAS. Both simulation and assimila tion results of the land model reflected reasonably the temporal-spatial distribution of soil moisture. The assimilated soil mois ture distribution matches very well with severe summer droughts in Chongqing and Sichuan Province in August 2006, the worst since the foundation of the People’s Republic of China in 1949. It also matches drought regions that occurred in eastern Hubei and southern Guangxi in September.展开更多
文摘中国覆盖比较完整的台站观测始于1951年，1951年之前虽然有一些观测记录，但是残缺不全。所以要建立更长的气候序列就要吸收代用资料，但是代用资料可能与气候要素仅有一定程度的相关，不可能一一对应，因此应用代用资料重建的气候序列有一定的不确定性。英国East Anglia大学的Climatic Research Unit（简称CRU）通过整合已有的若干个知名数据库，重建了一套覆盖完整、高分辨率、且无缺测的月平均地表气候要素数据集，时间范围覆盖1901-2003年，空间为0．5°×0．5°经纬网格覆盖所有陆地。这套资料和中国已有的气候数据相比具有如下优点：第一，中国西部20世纪前半期非常缺少观测，CRU资料尽管包含插值带来的误差，经比较仍可作为有一定信度的参考；第二，中国现有的百年温度序列只是年或季分辨率，而CRU资料达到月分辨率；第三，建立这个序列仅使用观测结果，做统计内插，不包括代用资料所带来的不确定性。因此，CRU的序列与用代用资料补充得到的序列在资料方面有较大不同，比较这两个序列，不仅可以进一步确认中国气候变化的特征，也可以彼此校正。结果表明：（1）CRU资料反映的全国年平均温度年际变化和考虑代用资料重建的序列吻合得很好，相关系数达到0．84；（2）区域尺度上，两者在10个典型分区的气温变率也相当一致，相关整体保持在0．8左右，仅新疆西南部和西藏西北部两者差异较大；（3）CRU资料揭示的中国年总降水量在1951～2000年的变化与160站观测吻合，相关系数达到0．93；（4）CRU资料的中国东部四季降水量和重建资料十分一致，秋季一致性最好，相关0．93；（5）CRU资料和重建的序列比较一致地表现出中国温度和降水年代际变化的主要特征，其给出的20世纪20年代中国大旱和20世纪40年代中国高温的空间�
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 49725308, 40023003 and 49894170) the National "973" Project (Grant No. G199043) the Knowledge Innovation Engineering Project (Grant Nos. KZCX1-Y-05 and KZCX2-108
文摘Through the use of reliable AMS dating of high resolution (15-30 years) peat and the establishment of monsoon climate proxies sequence, we have been able to recognize several cold, dry events in the Tibetan Plateau during the Holocene. The more obvious ones occurred around 12800, 11300, 10200, 9580, 8900, 6400, 4400, 3700, 2800 and 1500 cal. aBP. These events correlate well with both ice rafting events recorded in high latitude North Atlantic Ocean sediment cores and cooling events in the low latitude SST. Spectral analysis indicates high frequency climate variation on centennial-millennial time scale during the Holocene. This further reflects Holocene climate instability and the existence of centennial-millenium scale rhythm in mid latitude areas as well.
基金supported by National High Technology Research and Development Program of China (Grant Nos. 2007AA12Z144, 2009AA12Z129)Chinese COPES Project (Grant Nos. GYHY200706005, GYHY200806014)China Meteorological Administration New Technology Promotion Project (Grant No. CMATG2008Z04)
文摘Soil moisture plays an important role in land-atmosphere interactions. It is an important geophysical parameter in research on climate, hydrology, agriculture, and forestry. Soil moisture has important climatic effects by influencing ground evapotranspi ration, runoff, surface reflectivity, surface emissivity, surface sensible heat and latent heat flux. At the global scale, the extent of its influence on the atmosphere is second only to that of sea surface temperature. At the terrestrial scale, its influence is even greater than that of sea surface temperatures. This paper presents a China Land Soil Moisture Data Assimilation System (CLSMDAS) based on EnKF and land process models, and results of the application of this system in the China Land Soil Moisture Data Assimilation tests. CLSMDAS is comprised of the following components: 1) A land process mo del—Community Land Model Version 3.0 (CLM3.0)—developed by the US National Center for Atmospheric Research (NCAR); 2) Precipitation of atmospheric forcing data and surface-incident solar radiation data come from hourly outputs of the FY2 geostationary meteorological satellite; 3) EnKF (Ensemble Kalman Filter) land data assimilation method; and 4) Observa tion data including satellite-inverted soil moisture outputs of the AMSR-E satellite and soil moisture observation data. Results of soil moisture assimilation tests from June to September 2006 were analyzed with CLSMDAS. Both simulation and assimila tion results of the land model reflected reasonably the temporal-spatial distribution of soil moisture. The assimilated soil mois ture distribution matches very well with severe summer droughts in Chongqing and Sichuan Province in August 2006, the worst since the foundation of the People’s Republic of China in 1949. It also matches drought regions that occurred in eastern Hubei and southern Guangxi in September.
