西北太平洋7月海雾频率年际变化及全球变暖背景下的可能趋势

发布时间：2018-01-18 05:04

本文关键词：西北太平洋7月海雾频率年际变化及全球变暖背景下的可能趋势　出处：《中国海洋大学》2014年硕士论文　论文类型：学位论文

【摘要】：本文利用ICOADS（International Comprehensive Ocean-Atmosphere Data Set）31年（1979-2009）的船测能见度资料和同时期CFSR（Climate Forecast SystemReanalysis）再分析云水含量数据，，统计西北太平洋中纬度（40oN-50oN，140oE-170oW）7月海雾发生频率，并研究其年际变化。多雾少雾年合成分析表明大气环流形势异常是影响西北太平洋7月份海雾频率变化的主要因素。在多雾年（海雾频率异常高），西北太平洋副热带高压中心东移，其西侧的南风气流导致副热带地区大量水汽向北输送，同时，中纬度地区出现较强的高压脊，有利于大气层结的稳定。充足的水汽和稳定的大气层结有助于西北太平洋中纬度地区海雾的形成。相反，在少雾年（海雾频率异常低），副热带高压西伸和南移，水汽几乎无法到达中纬度地区，同时，中纬度异常槽和异常偏北风减弱背景南风和大气稳定层结，不利于海雾的发生。西北太平洋中纬度地区的低空物理要素（例如相对湿度，水汽通量，气海温差等）受到环流形势的影响，在多雾年（少雾年）呈现出有利于（不利于）海雾发生的特征。通过个例分析，证明了海雾发生时，气团来自于副热带地区，并且当气块经过黑潮延伸体时，保持高温高湿的性质，之后在中高纬冷海面上迅速降温成雾，在非雾天气个例中并无此特征。最后，根据环流形势与海雾频率变化关系，利用CMIP5(Coupled Model IntercomparisonProject Phase5) RCP (Representative Concentration Pathway)4.5和8.5试验数据，预估未来环流形势，发现未来海雾频率呈现减少的趋势。
[Abstract]:This article uses ICOADS(International Comprehensive Ocean-Atmosphere Data Settings for 31 years. Ship survey visibility data and CFSR(Climate Forecast system analysis data from 1979 to 2009). The cloud water content data were analyzed again. The occurrence frequency of sea fog in July of 40oN-50oNC140oE-170oWN in the mid-latitude of the Northwest Pacific Ocean is calculated. It is shown that the anomalous atmospheric circulation situation is the main factor affecting the sea fog frequency in the Northwest Pacific Ocean in July, and in the multi-fog years (the sea fog frequency is abnormally high). The center of the northwest Pacific subtropical high moves eastward, and the southward wind current in the west leads to a large amount of water vapor being transported northward in the subtropical region. At the same time, a strong ridge of high pressure appears in the mid-latitude region. Sufficient water vapor and stable atmospheric stratification contribute to the formation of sea fog in the mid-latitudes of the Northwest Pacific Ocean. On the contrary, in less fog years (the frequency of sea fog is abnormally low). The subtropical high extends westward and moves southward, and the water vapor can hardly reach the mid-latitude area. At the same time, the anomalous trough and the anomalous northerly wind weaken the background south wind and the stable stratification of the atmosphere. The low-altitude physical elements (such as relative humidity, water vapor flux, air-sea temperature difference, etc.) in the mid-latitudes of the Northwest Pacific Ocean are affected by the circulation situation. In the years with more fog (less fog), the characteristics of sea fog are favorable (unfavorable). It is proved that the air mass comes from the subtropical region when the sea fog occurs, and when the gas block passes through the Kuroshio extension, it is proved that the air mass comes from the subtropical region when the sea fog occurs. The property of high temperature and high humidity is maintained, and then the fog is rapidly cooled on the cold sea surface in middle and high latitudes, but not in the case of non-foggy weather. Finally, according to the relationship between the circulation situation and the frequency variation of sea fog. Using CMIP5(Coupled Model IntercomparisonProject phase 5) RCP (. Representative Concentration Pathway)4.5 and 8.5 test data. Predicted the future circulation situation, discovered the future sea fog frequency to present the reduction tendency.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P732

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