A meteorological overview of the TC4 mission
A meteorological overview of the TC4 mission
复制标题
TC4 任务的气象概述
DOI：
--
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
P. Newman
中科院分区：
文献类型：
--
作者：
L. Pfister;H. Selkirk;D. Starr;K. Rosenlof;P. Newman
[1]2007年夏季在中美洲的TC 4使命任务研究了进入热带UTLS的对流输送和卷云的演变。热带对流层顶（TTL）环流主要由亚洲季风反气旋和从西太平洋延伸到大西洋的向西控制。在TC 4期间，中美洲上空的TTL向西流动比正常情况下强。中美洲区域的冷云发生率是34年抽样中第三低的。主要因素是拉尼娜现象的初期，特别是南美洲太平洋沿岸的寒冷气温。加勒比海低空急流的减弱导致最冷的云层从加勒比海转移到中美洲的太平洋一侧。对流层顶温度变率的特征是由局地对流和非局地对流产生的向上传播的波动。这些波产生的对流层顶温度变化为3 K，峰-峰变化为8 K。在中美洲的低层，来自撒哈拉沙漠的气流占主导地位;再往南，空气来自亚马逊地区。对流层上层受对流影响的空气来自中美洲、北方亚马逊地区、大西洋ITCZ和北美季风。在TTL中，亚洲和非洲的对流影响了观测到的气团。中美洲TTL北纬10度以北，非洲和亚洲对流对气团的贡献可能与中美洲和南美洲对流一样大。8 N以南，亚洲和非洲对流的影响要小得多。
[1] The TC4 mission in Central America during summer 2007 examined convective transport into the tropical UTLS and the evolution of cirrus clouds. The tropical tropopause layer (TTL) circulation is dominated by the Asian monsoon anticyclone and westward winds that stretch from the western Pacific into the Atlantic. During TC4, TTL westward flow over Central America was stronger than normal. Incidence of cold clouds over the Central American region was the third lowest out of 34 years sampled. The major factor was an incipient La Nina, specifically anomalously cold temperatures off the Pacific Coast of South America. Weakness in the low level Caribbean jet caused a shift in the coldest clouds from the Caribbean to the Pacific side of Central America. The character of tropopause temperature variability was that of upward propagating waves generated by local and nonlocal convection. These waves produced tropopause temperature variations of 3 K, with peak-to-peak variations of 8 K. At low levels in Central America, flow from the Sahara desert predominated; further south, the air came from the Amazon region. Convectively influenced air in the upper troposphere came from Central America, the northern Amazon region, the Atlantic ITCZ, and the North American monsoon. In the TTL, Asian and African convection affected the observed air masses. North of 10N in the Central American TTL, African and Asian convection may have contributed as much to the air masses as Central and South American convection. South of 8N, Asian and African convection had far less impact.