夏季风建立期间低层流场的变化及其与中国雨带活动的关系

本利用多年欧洲中心格点风和中国降水资料，分析了夏季风建立期间，亚洲南部及其邻近海域上低层流场的变化和雨带在中国南方的活动。结果表明，夏季风于5月中在南海地区建立。低层流场的变化主要表现为副热带高压脊从南海的东撤和气旋性气流切变线从中国西南向华南沿海的东伸。相应地，雨带有一次从南移转向北推的过程。由于5月份中南半岛－南海区域一直为西南气流所影响，因此，很难从风向来判断气流性质的变化，相对而言，雨带北移能更好地反映出夏季风向北扩散的地理位置。     

Study on response of ecosystem to the East Asian monsoon in eastern China using LAI data derived from remote sensing information

Based on the leaf area index (LAI) data derived from remote sensing information and eco-climate data, the responses of regional ecosystem variations in seasonal and interannual scales to the East Asian monsoon are studied. It is found that the vegetation ecosystems of eastern China are remarkably correlated with the East Asian monsoon in seasonal and interannual scales. In the seasonal timescale, the obvious variations of the vegetation ecosystems occur with the development of the East Asian monsoon from the south in the spring to the north in the autumn. In the interannual scale, high LAI appears in the strong East Asian monsoon year, whereas low LAI is related to the weak East Asian monsoon year. These further lead to the characteristic of "monsoon-driven ecosystem" in the eastern China monsoon region, which can be revealed by LAI.     

Natural interdecadal weakening of East Asian summer monsoon in the late 20th century

Based on the reanalysis data throughout 1948-2002 as derived from the United States National Centers for Environmental Prediction and National Center for Atmospheric Research, it is revealed that East Asian summer monsoon （EASM） intensity weakens on an interdecadal timescale since the mid-1960s, and twice interdecadal jumps are recorded in the EASM intensity index series in the late 20th century, respectively occurring in the mid-1960s and mid- to late 1970s. Six globally coupled atmosphere-ocean models＇ outputs under the SRES A2 greenhouse gas and aerosol emission scenario, provided by the IPCC Data Distribution Center and the Hadley Center for Climate Prediction and Research, are then systematically examined. It follows that the above EASM weakening is not closely related to synchro- nizing anthropogenic global warming, and, therefore, it should be qualitatively natural change process. Over the 21st century, the EASM intensity is likely increased slightly by continually intensified greenhouse effect relative to the late 20th century.     

Pollen record from red clay sequence in the central Loess Plateau between 8.10 and 2.60 Ma

The origin and development of Asian monsoon circula-tion, the desertification and aridification of Asian inland in relation to vegetation evolution and the soil erosion in northwest China have been more and more drawing inten-sive scientific and society attention. Recently the studiesof monsoon evolution from some Tertiary Red Clay sec-tions located at the central Loess Plateau in the eastern Liupan Mountains, based on chronology, dust flux, grains size, magnetic susceptibility, and rates o…     

夏热冬冷地区村镇住宅室内热环境的改善措施

通过对夏热冬冷地区气候特征、村镇住宅热工质量的分析,并根据村镇住宅自身的特殊性,提出了有利于冬季保温、夏季防热的热环境质量的措施。     

Reconstruction of surface ocean water <Emphasis Type="Italic">p</Emphasis>CO<Subscript>2</Subscript>(aq) in Nansha area,the South China Sea during the last 30 ka

The reconstruction of pCO2 in the tropic ocean is one of the most important issues to understand global climatic changes.In this study,the high-resolution stratigraphic analysis of core 17962 was conducted,which is Iocated in the southern South China Sea(SCS).The contents of sedimentary organic matter,the stable carbon isotopic composition of sedimentary organic matter,and the δ^13C values of black carbon and terrigenons n-alkanes were determined.And the δ^13Cwc value of carbon derived from aquatic was calculated.On the basis of δ^13Corg-pCO2equation proposed by Popp et al.(1989),we estimated the pCO2 in the Nansha area,SCS,since the last glaciation using δ^13Cwc instead of δ^13Corg.The results show that the average pCO2 was estimated at 240 ppm V during the last glaciation,and at 320ppm V in the Holocene.A comparison of surface sea pCO2 with the atmosphere CO2 recorded in the Vostok ice core,indicates that CO2 in surface water of the southern SCS could emit into atmosphere during the last 30ka.     

A high-resolution stalagmite O-C isotope record from Nanjing and its rapid response to climatic events

Here we discussed rapid response of the cave temperature and vegetation to the four Dansgaard-Oeschger cold and warm cycles during 50-40 kaBP based on results of oxygen and carbon stable isotopic compositions from a stalagmite in Tangshan, Nanjing. It is found that the amount of C₃ vegetation relative to C₄-type declines during the D-O warm events, indicating the decrease of the effective meteoric precipitation. Compared with O-isotope records of the Greenland ice core, the stalagmite record displays a very similar pattern to Greenland ice core record over the decade-century time scale, suggesting that the changes of the East Asian monsoon climate are in accordance with the high-latitude polar climate in the short-term time scale. The age of the ice-rafted H5 event in the stalagmite record, however, preceded that of Greenland ice cores by 2 ka. This out of phase between the remote areas cannot be yet proven because the two time scales were determined from different dating methods.     

Persistent anomalous flows over the subtropical western Pacific in summer

The distribution of global persistent anomaliesshows that the subtropical western Pacific is a key region with high-frequency occurrence of persistent anornalics. Analyscs of streamfunction anomalies, 013 anomalies etc. suggest that the convective heating related to Indian nlon.uwn might he responsible for the development of WPA. The results of numerical experiment by two linear bamtmpic rnodcls support the observation.     

北京地区夏季中间尺度云团形成的环境特征

使用对比度分析方法对影响北京地区夏季的中间尺度云团形成的环境特征及其与强天气的关系进行详细分析,研究得出６～８月云团发生具有局地强风暴和暴雨的综合环境特征,加深了对中间尺度云团的了解,对改进强天气的预报有参考意义     

Summer sea-surface temperatures and climate events on the North Icelandic shelf through the last 3000 years

Diatom data from core MD992271 on the North Icelandic shelf record a cooling trend through the last 3000 years. This is indicated by a general decrease in warm water species and an increase in cold water taxa. The relative abundance of these two diatom groups changed periodically, suggesting that the climate also fluctuated within this time period. The results of diatom-based transfer function calculation show that the summer sea-surface temperatures (SSTs) before 1400 cal. a BP were generally higher than the mean value for the last 3000 years and the summer SSTs fluctuated around the mean between 1400 and 700 cal. a BP, and dropped to the values below the mean after 700 cal. a BP. Four cooling events were distinguished, centered at around 2600, 1900, 1300 and 600 cal. a BP respectively. The results are not only consistent with the data from neighbouring cores HM107-03 and MD992275, but also comparable with those from the GISP2 ice core and from other marine sediment records in the North Atlantic. This suggests that changes in the summer SSTs reflect regional climate variations in the North Atlantic. On the North Icelandic shelf, the summer SST variation is a result of changes in the in-teraction between the cold and the warm currents in the area.