我国东部海洋温度锋区对大气的强迫作用——季节变化  

Ocean-to-Atmosphere Forcing in the Vicinity of the Sea Surface Temperature Front in the East China Sea-Seasonal Variations

作　　者：徐蜜蜜[1,2] 徐海明[2] 朱素行[2] 周林义[3] 

机构地区：[1]南京信息工程大学气象灾害省部共建教育部重点实验室,南京210044 [2]南京信息工程大学大气科学学院,南京210044 [3]江苏省气象科学研究所,南京210008

出　　处：《大气科学》2012年第3期590-606,共17页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金资助项目40975024;全球变化研究国家重大科学研究计划2012CB955600;江苏省研究生培养创新计划CX10B_286Z

摘　　要：采用一系列高分辨率的卫星资料研究了我国东部海区的海洋温度锋对局地大气的强迫作用及其季节变化。分析表明,当春季海洋锋增强时,海温与海表面风速之间存在明显的正相关关系,并且在海洋锋的暖(冷)侧形成海表风的辐合(辐散),表现为海洋对大气的强迫作用。海温对表面风场的影响程度与海洋锋的强度成正比,春季影响程度最大,夏、秋季最小。海洋锋对其附近的总降水、对流、层云降水均有影响,尤其在春季海洋锋暖侧的降水强度增大,对流降水的频次增多,"雨顶"高度也有明显的抬升。暖流对大气的影响不仅局限在边界层,其影响可达整个对流层。另外,分析发现对流降水对海温的响应比层云降水更加敏感。研究还表明,暖流上空高、低云呈现相反的年循环特点,冬季多0.5～2km的边界层云,夏季多云底在10km以上的高云。深对流云集中出现在3～6月,从冬季到初夏,30%以上的云量中心抬高了接近8km。春季和初夏在海洋锋的暖侧频繁地出现深对流活动。A suite of high-resolution satellite measurements are used to investigate local atmospheric response to a sea surface temperature （SST） front over the East China Sea and its seasonal variation. The analyses reveal a significant in-phase relationship between SST and 10-m neutral wind velocity, accompanied by convergence （divergence） on the warmer （colder） flank of the front during spring time when the oceanic front is intensified, indicative of ocean-to-atmosphere influences. The extent of the influence on near surface wind field by SST is proportional to the strength of the SST front with its maximum in spring and minimum in summer and autumn. The satellite observa- tions detect direct responses of total, convective, and stratiform precipitation to the Kuroshio front. Especially in spring and early summer, enhanced rainfall and the frequent occurrence of convective precipitation are collocated on the warmer flank of the SST front. Furthermore, considerable increase in the cloud top height is observed across the front from cold to warm water. The distribution and structure of precipitation suggest that the influence of warm ocean current in the Fast China Sea penetrates above the MABL （Marine Atmospheric Boundary Layer） to reach the entire troposphere. The results also show that convective precipitation is more sensitive to SST variation than strati- form precipitation. High and low clouds over the Kuroshio Current exhibit opposite annual cycle, low clouds ranging from 0. 5 - 2 km prevail in winter, while high clouds with the cloud base above 10 km dominate in summer. The area with cloud amount larger than 30% is elevated by nearly 8 km from winter to early summer. Deep convective clouds mainly concentrate during March to June, indicating that deep convection frequently occurs on the warmer flank of the SST front in spring and early summer.

关 键 词：卫星资料 海洋锋 海洋对大气的影响 季节变化 

分 类 号：P461[天文地球—大气科学及气象学]