北极中央区海冰密集度与云量相关性分析

本文使用海冰密集度以及低云、中云、高云的日平均数据,借助滑动相关分析方法,研究了北极中央区海冰密集度与云量之间的相关性,分析了海冰与云的相互作用机制。研究表明,在春季海冰融化季节(4、5月)、秋季海冰冻结季节(10、11月),低云与海冰密集度之间表现为较好的负相关,表明在这段时间内冰区海面蒸发强烈,对低云的形成有重要贡献。在10月和11月,中云与海冰密集度也有很好的负相关,表明秋季低云可以通过抬升形成中云。高云与海冰密集度之间并没有明显的相关性,可能原因:一方面海冰的空间分布对高云无影响,另一方面,高云主要影响到达的短波辐射,从而影响海冰的融化和冻结速度,与海冰厚度有直接显著的关系,而与海冰密集度的关系不明显。此外,在海冰密集度与低云存在较好负相关的情况下会出现某些年份相关性不好的情况,我们的研究发现这是北极中央区与周边海区发生了海冰交换或云交换的结果。

Analysis of correlation between sea ice concentration and cloudiness in the central Arctic

Correlation between sea ice concentration and cloudiness in the central Arctic is studied. The running correlation coefficients of daily sea ice concentration averaged for whole central Arctic with the daily averaged low cloud, medium cloud and high cloud are calculated. During the melting period in spring (April and May) and the freezing period in autumn (October and November), sea ice concentration and low cloud present significant negative correlation. This could be explained that the low clouds were formed by strong evaporation from the open water in gaps of sea ice during these periods. In the same period, sea ice concentration is negatively correlated with medium cloud only during the freezing period in autumn, which suggests that in autumn the low cloud could upwell to form medium cloud, but in spring the upwell is much week because of its stable stratification. There is no a significant correlation between sea ice concentration and high cloud, which is speculated that sea ice can't influence the high cloud and the high cloud is not formed by local eveporation and the influence of high cloud on sea ice is not ice concentration, but is ice thickness. In the periods of significant correlation between ice concentration and low cloud, there still exist some occasional inconsistent betweeen them. The exchanges of sea ice or cloud between the central Arctic and adjacent regions is suggested to cause the inconsistent.