A continuous pollen record from the Zoige Basin in the northeastern Qinghai-Tibetan Plateau not only provides information on the vegetation and climate changes during the last two glacial/interglacial cycles, but also...A continuous pollen record from the Zoige Basin in the northeastern Qinghai-Tibetan Plateau not only provides information on the vegetation and climate changes during the last two glacial/interglacial cycles, but also gives proof to establish the time scale of the upper 60 m of the RM core. Subalpine spruce-fir forests colonized the Zoige Basin during the interglacials and interstadials, implying warm and wet climate conditions. Alpine periglacial desert or dry desert may have existed during the penultimate glacial and the last glacial maxima, respectively. Alpine sedge meadow dominated the landscape during MIS 4. The MIS 3 is punc- tuated by a number of stadials similar to those documented in the Guliya and GISP2 ice cores, as indicated by repeated rise and fall of subalpine spruce-fir forests. Our pollen re- cord reveals a regional climate history similar to those from the neighboring sites, including the Arabian Sea and the Guliya ice core, and thus supports the notion that the Qing- hai-Tibetan Plateau acts as an important link between cli- matic events in the North Atlantic realm and the Asian mon- soon domain.展开更多
On the gradient observational data of the atmospheric surface layer from September 1997 to December 1998 collected by two sets of Automatic Weather Station (AWS) installed in Gaize and Shiquanhe on the western Tibetan...On the gradient observational data of the atmospheric surface layer from September 1997 to December 1998 collected by two sets of Automatic Weather Station (AWS) installed in Gaize and Shiquanhe on the western Tibetan Plateau, mean surface roughness lengths at the two stations above are determined to be 2.7 and 2.9 cm, respectively. The bulk transfer coefficients each day are computed by the profile-flux method, means of the bulk transfer coefficient for momentum (i.e. drag coefficient) in 1998 are 4.83×10-3 and 4.75×103 at the two stations. The surface fluxes of momentum, sensible heat and latent heat each day are further estimated by the bulk formulas, annual mean of these fluxes is 3.4×10-2 and 1.8×102N/m2, 73.1 and 67.2 W/m2, 15.4 and 2.9 W/m2, respectively. The diurnal and seasonal variations are obtained by a composite method and the relationships among the heat transfers between land and atmosphere, plateau monsoon and plateau rain season are also discussed.展开更多
基金This work was supported by 973 Project of China(Grant No.998040810)the National Key Project for the Qinghai-Tibetan Plateau in the Eighth Five year Project of China+1 种基金the National Natural Science Foundation of China(Grant Nos.49371068 and 49871078)the U.S.National Science Foundation.
文摘A continuous pollen record from the Zoige Basin in the northeastern Qinghai-Tibetan Plateau not only provides information on the vegetation and climate changes during the last two glacial/interglacial cycles, but also gives proof to establish the time scale of the upper 60 m of the RM core. Subalpine spruce-fir forests colonized the Zoige Basin during the interglacials and interstadials, implying warm and wet climate conditions. Alpine periglacial desert or dry desert may have existed during the penultimate glacial and the last glacial maxima, respectively. Alpine sedge meadow dominated the landscape during MIS 4. The MIS 3 is punc- tuated by a number of stadials similar to those documented in the Guliya and GISP2 ice cores, as indicated by repeated rise and fall of subalpine spruce-fir forests. Our pollen re- cord reveals a regional climate history similar to those from the neighboring sites, including the Arabian Sea and the Guliya ice core, and thus supports the notion that the Qing- hai-Tibetan Plateau acts as an important link between cli- matic events in the North Atlantic realm and the Asian mon- soon domain.
文摘On the gradient observational data of the atmospheric surface layer from September 1997 to December 1998 collected by two sets of Automatic Weather Station (AWS) installed in Gaize and Shiquanhe on the western Tibetan Plateau, mean surface roughness lengths at the two stations above are determined to be 2.7 and 2.9 cm, respectively. The bulk transfer coefficients each day are computed by the profile-flux method, means of the bulk transfer coefficient for momentum (i.e. drag coefficient) in 1998 are 4.83×10-3 and 4.75×103 at the two stations. The surface fluxes of momentum, sensible heat and latent heat each day are further estimated by the bulk formulas, annual mean of these fluxes is 3.4×10-2 and 1.8×102N/m2, 73.1 and 67.2 W/m2, 15.4 and 2.9 W/m2, respectively. The diurnal and seasonal variations are obtained by a composite method and the relationships among the heat transfers between land and atmosphere, plateau monsoon and plateau rain season are also discussed.
