不同太平洋年代际振荡和ENSO位相下大气水分收支变化对北半球冬季太平洋蒸发量的影响

发布时间：2019-07-13 08:47

【摘要】：本文利用OAFlux资料研究了1958~2015年北半球冬季太平洋蒸发量在不同厄尔尼诺—南方涛动(ENSO)和太平洋年代际振荡(PDO)位相下的分布特征,并从水汽收支的角度分析了蒸发量异常的成因,结果表明:ENSO主要影响热带东太平洋、副热带西北太平洋和中纬度北太平洋中部的蒸发量。El Ni?o(La Ni?a)时水汽在北太平洋中部异常辐散(辐合),有利于当地大气水汽含量减小(增大),造成蒸发量增大(减小);副热带西北太平洋异常的水汽辐合(辐散)有利于蒸发量减小(增大);除此以外,蒸发量在热带东太平洋蒸发量增大(减小)则主要是降水量增大(减小)导致。与此同时,ENSO对上述海区蒸发量的影响还受到PDO的调控,当PDO处于暖(冷)位相时,El Ni?o(La Ni?a)造成蒸发量异常程度在中纬度北太平洋中部显著增大,这主要是由降水量增大(减小)引起的大气水汽含量减小(增大)所致,此时对应着风暴轴异常增大(减小);当PDO处于冷(暖)位相时,El Ni?o(La Ni?a)造成的蒸发量异常程度在副热带西北太平洋和热带东太平洋显著增大,而这与湿度变化引起的水汽平流异常程度增大紧密相关。
[Abstract]:In this paper, the distribution characteristics of Pacific evaporation in the northern hemisphere winter from 1958 to 2015 under different El Ni 帽 o Southern Oscillation (ENSO) and Pacific Interdecadal oscillatory (PDO) phases are studied by using OAFlux data, and the causes of evaporation anomalies are analyzed from the point of view of water vapor budget. The results show that ENSO mainly affects the tropical eastern Pacific. The evaporation of the subtropical northwest Pacific and the middle latitudes of the North Pacific. The abnormal divergence (convergence) of water vapor in the central North Pacific during El Ni?o (La Ni?a) is beneficial to the decrease (increase) of local atmospheric water vapor content and the increase (decrease) of evaporation. The abnormal water vapor convergence (divergence) in the subtropical northwest Pacific is beneficial to the decrease (increase) of evaporation, in addition, the increase (decrease) of evaporation in the tropical eastern Pacific is mainly caused by the increase (decrease) of precipitation. At the same time, the influence of ENSO on evaporation in the above sea area is also regulated by PDO. When PDO is in warm (cold) phase, the abnormal degree of evaporation caused by El Ni?o (La Ni?a) increases significantly in the middle of the middle latitudes of the North Pacific Ocean, which is mainly caused by the decrease (decrease) of atmospheric water vapor content caused by the increase (decrease) of precipitation, which corresponds to the abnormal increase (decrease) of storm axis. When PDO is in cold (warm) phase, the abnormal degree of evaporation caused by El Ni?o (La Ni?a) increases significantly in the subtropical northwest Pacific and the tropical eastern Pacific, which is closely related to the increase of water vapor advection anomaly caused by humidity change.
【作者单位】：兰州大学大气科学学院;扬州大学物理科学与技术学院;国家气候中心;
【基金】：国家自然科学基金项目41530531;41375078;41575074 国家重点基础研究发展计划(973计划)项目2013CB430204~~
【分类号】：P732.6

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