P-J遥相关型与西北太平洋海雾的关系

发布时间：2018-12-29 08:57

【摘要】：本文利用中国沿海台站海雾观测资料、ICOADS（International ComprehensiveOcean-Atmosphere Data Set）能见度观测资料、GPCP降水和NCEP再分析资料等，研究了7月太平洋-日本遥相关型（Pacific-Japan teleconnection，P-J型）对千岛群岛以东海域海雾的影响，7月至8月黄渤海海雾频数“骤降”现象与P-J型位相转换的关系，最后还结合CMIP5模式预估了全球变暖背景下的西北太平洋海雾的可能变化趋势。相关分析表明7月千岛群岛以东海雾指数与P-J指数相关性最好，达0.62并通过99%信度检验，且P-J型正位相年海洋大气条件有利于海雾的形成。异常正负位相年合成分析表明正位相年西太副高偏北偏东，千岛群岛以东海域南风偏强，水汽辐合；同时，，正位相年南风以水平风为主，而负位相年具有明显垂直上升速度，在这种背景环流下有利于降低海洋大气边界层高度，加之正位相950hPa暖平流较强有利于强逆温层的形成。正异常年涡度平流经向输送、负位相年纬向输送的的分布特征表明涡度平流分布的差异是造成位势高度场的差异可能原因。“南云北雾”的结构可能与P-J型异常环流的位相以及黑潮延伸体海洋锋对边界层内强迫有关。千岛群岛以东海雾指数与La Ni a关系的分析和P-J型指数与印度洋海盆模态的分析表明，P-J型遥相关是一种“大气桥”联系热带与中纬度，通过影响大气环流影响千岛群岛以东海雾的变化。季节内P-J型位相转换分析表明，P-J型是西太夏季大气异常环流的主模态，其位相具有显著的季节内变化，稳定的转换半周期约4候。西太副高位置的季节内变化对P-J型的形成有贡献。菲律宾海西北向Rossby波能量传播促使中纬度负涡度向西扩展，加之8月亚洲中高纬度位势高度异常升高使黄渤海偏东风分量加强。过去40多年中7月和8月之间西北太平洋大气环流变化呈提前发生的趋势，其促使年代际尺度P-J型位相转换提前约2候，进而导致黄东海异常东风提前发生。异常东风促使向北的水汽输送减少、黄东海近海面大气层结稳定性减弱等不适宜海雾生成和发展的气象条件出现从而使雾季结束，所以年代际东风异常提前可能是7、8月中国近海海雾频数下降的主要原因。结合CMIP5中15个模式的位势高度、风场、比湿和云水含量等变量的预估分析表明，21世纪下半叶P-J型负位相发生频率可能较高，而副高向西北方向伸展可能是造成上述变化的原因之一；负位相环流型影响多种海洋气象条件变化可能导致千岛群岛以东海域海雾频数减少，海雾频率高值区北移。
[Abstract]:Based on the observational data of, ICOADS (International ComprehensiveOcean-Atmosphere Data Set) visibility, GPCP precipitation and NCEP reanalysis of sea fog observed at coastal stations of China, the July Pacific to Japan teleconnection model (Pacific-Japan teleconnection,) is studied. The influence of P-J type) on sea fog in the sea east of Kuril Islands, and the relation between the phenomenon of "sudden drop" of fog frequency in the Yellow Sea and Bohai Sea from July to August and the phase transition of P-J type. Finally, combined with CMIP5 model, the possible trends of sea fog in the Northwest Pacific Ocean under the background of global warming are predicted. The correlation analysis shows that the correlation between fog index and P-J index in the East China Sea is the best in July, reaching 0.62 and passing the reliability test of 99%, and the marine atmosphere condition of P-J positive phase year is favorable to the formation of sea fog. The analysis of positive and negative phase years shows that the western-too subtropical high is north-east of the positive phase year, and the south wind is stronger in the sea area east of the Kuril Islands, and the water vapor converges. At the same time, the south wind is mainly horizontal wind in the positive phase year, while the vertical rising velocity is obvious in the negative phase year. Under this kind of background circulation, the height of the boundary layer of the ocean atmosphere is reduced, and the strong warm advection of the positive phase 950hPa is favorable to the formation of the strong inversion layer. The distribution characteristics of positive annual vorticity plain flow and negative phase annual zonal transport indicate that the difference of vorticity advection distribution is the possible cause of the difference of potential height field. The structure of "Nanyunbei Fog" may be related to the phase of P-J anomalous circulation and the forcing of the Kuroshio extensional oceanic front to the boundary layer. The analysis of the relationship between fog index and La Ni a in the East China Sea and the analysis of P-J type index and the mode of the Indian Ocean basin show that the P-J type teleconnection is a kind of "atmospheric bridge" connecting the tropics and mid-latitudes. The variation of fog in the East China Sea is affected by the influence of atmospheric circulation. The analysis of phase transition of P-J pattern in season shows that P-J type is the main mode of anomalous atmospheric circulation in the western Pacific summer. The phase of P-J pattern has significant variation in season, and the stable transition half period is about 4 hours. The intraseasonal variation of the West Pacific Subtropical High contributes to the formation of the P-J type. The energy propagation of the Rossby waves in the Philippines promotes the westward expansion of the negative vorticity in the mid-latitudes, and the anomalous elevation of the geopotential height in the mid-high latitudes of Asia in August strengthens the easterly component in the Yellow Sea and Bohai Sea. In the past 40 years, the variation of atmospheric circulation in the Northwest Pacific Ocean occurred earlier than that in July and August, which led to the advance of the Interdecadal P-J type phase transition, which led to the occurrence of the anomalous easterly wind in the East China Sea and the Yellow Sea earlier. The anomalous easterly wind causes the northward vapor transport to decrease, the stability of atmospheric stratification near the sea surface of the Yellow Sea and the East China Sea weakens, and other weather conditions that are not suitable for the formation and development of sea fog, thus bringing the fog season to an end. So the interdecadal easterly anomaly may be the main reason for the decrease of sea fog frequency in July and August. Combined with the prediction analysis of 15 models in CMIP5, such as potential height, wind field, specific humidity and cloud water content, the occurrence frequency of P-J negative phase may be higher in the second half of the 21st century. The extension of the subtropical high to the northwest may be one of the reasons for the above changes. The negative circulation pattern may result in the decrease of sea fog frequency and the northward shift of sea fog frequency in high value areas east of the Kuril Islands.
【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

【参考文献】