摘要
采用不同区域边界层综合观测系统,从地表能量收支平衡的视角,探讨青藏高原与四川盆地能量平衡各分量结构特征,进一步认识云状况对能量平衡分量的影响问题。研究表明,青藏高原东南部大理、林芝、温江各站地表通量感热、潜热与有效能源两项相关特征明显,即存在能量闭合基本特征,但能量收支仍存在不闭合离散现象,尤其随着近地层地表通量与有效能源的增大,其非闭合特征更加明显。青藏高原东南部(大理、林芝)春、夏季低云量与感热呈显著负相关,潜热则呈不确定特征。对于春季低云量与感热相关性,高原东南部(大理、林芝)远比四川盆地(温江)相关更为显著,高原区域低云量对上述近地层"能量收支"起"冷却"作用,且低云量与向下长波辐射呈显著的正相关,此研究结果描述了低云量对陆面辐射强迫的"加热"反馈效应,即高原区域低云量状况亦可用边界层通量塔向下长波辐射量来间接表征。观测分析结果亦表明平原该站低云量对向下长波辐射影响远不如高原区域。研究结果表明,青藏高原区域与低云量有关的向下长波辐射高值区可能是出现近太阳常数现象的重要因素之一。
The Tibetan Plateau and the Loess Plateau in spring and summer are the high value areas of solar total radiation and land-air temperature difference,as well as the anomalous areas of cloud covers in China.The structural characteristics of the surface energy balance（SEB） components in the Tibetan Plateau and the Sichuan Basin are investigated in this paper using the boundary layer integrated system observations at Dali,Linzhi,and Wenjiang flux station,from the angle of energy balance,to further understand the impact of clouds’ status on the SEB components.The study indicates that on the southeast edge（Dali,Linzhi,Wenjiang） of the Tibetan Plateau,the sensible and latent heat（H＋LE） were significantly correlated with the available energy（Rn-G0）,showing the basic feature of SEB closure,but there still was a discrete phenomenon of SEB non-closure,especially in the surface layer where the feature of SEB non-closure became more obvious with increasing surface flux and available energy.The low cloud cover in the southeastern part（Dali,Linzhi） of the Tibetan Plateau in spring and summer was significantly negatively related with the surface sensible heat flux,but its correlation with the latent heat flux was weak and uncertain.The correlation between the low cloud cover and the sensible heat flux in spring was more significant in the southeast edge（Dali,Linzhi） than in the Sichuan Basin region（Wenjiang） and,the low cloud in the plateau region played a ＂cooling＂ role in the surface layer energy budget and the low cloud cover was significantly positively correlated with the downward long-wave radiation.This result describes the heating feedback effect of the radiation forcing of low clouds on the land surface,i.e.the low cloud status in the Tibetan Plateau could be indirectly expressed with the downward long-wave radiation fluxes observed at flux towers.The analyses of the observations also suggest that the impact of low clouds on the SEB at Wenjiang station situated in the Chengdu plain was far less than that in the Tibetan Plateau.The research results suggest that high value areas of the downward long waveradiation associated with low clouds might be one of the important influential factors for the occurrence of the near-solar constant phenomenon in radiation observation in the plateau.
出处
《气象学报》
CSCD
北大核心
2012年第4期837-846,共10页
Acta Meteorologica Sinica
基金
青藏高原对梅雨区水分循环及降水变异的影响(41130960)
中日政府间合作JICA计划
科技部国际合作项目(2009DFB20540)
科技部公益性行业(气象)科研专项(GYHY201006009)
灾害天气国家重点实验室自主研究项目(2009LASWZF02)
青藏高原及东侧观测布局关键技术研究(GYHY201006053)
关键词
青藏高原
能量收支
低云量与总云量
感热
辐射
Tibetan Plateau； Energy balance； Low cloud cover； Total cloud cover； Sensible heat； Radiation
