权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Ocean-atmosphere interaction over sea surface temperature front along Kuroshio Extension and North Pacific subtropical front.

沿黑潮延伸带和北太平洋副热带锋的海表温度锋面的海洋-大气相互作用。

基本信息

批准号：
17340137
负责人：
TANIMOTO Youichi
金额：
$ 10.36万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

Over the western North Pacific east of the Japan, sea surface temperature (SST) shows a steep front across the Kuroshio Extension (KE). The SST gradient near the KE is 5℃/200 km through seasons, therefore changes in SST are very large in that region. In the present study, we conducted global positioning system (GPS) radio sonde atmospheric soundings across the front in July 2005 (January 2006) as a research cruise of research vessel (R/V) Roger Revelle, Scripps Institute of Oceanography (R/V Hakuho-maru, Ocean Research Institute, University of Tokyo).In early summer, whilst the lower atmosphere overlying the KE region exhibits synoptic disturbances, SST front is nearly the same for several weeks during the cruise due the large inertia of the ocean. Analyses of the atmospheric soundings and ceilometer measurement show that the vertical structure of atmospheric boundary layer is modified across the front. In case of warm/moist (cold/dry) air mass overlying the KE region, a cloud regime shift from cumulus to low-level stratus, occasionally to fog (from stratus with solid cloud deck to broken stratus scattering with lower cloud base) is observed across warm-to-cold SST.In deep winter, the near surface is always unstable because of warm ocean and cool/dry atmosphere. Hence, the main inversion is formed at the top of well-mixed layer. Temporal variation of the mixed layer top (MLT), which is mostly corresponding to the observed cloud base, is well correlated with surface heat flux. The lag correlation becomes the maximum when the flux leads by 5-12 hours the MLT. After a passage of synoptic storm, the surface heat flux occasionally exceeded 800W m^<-2> and thereby the stratus and stratocumulus were formed at the MLT.These observational findings indicate that the marine atmospheric boundary layer is modified by the spatial changes in SST along the KE front even though the overlying atmosphere displays its synoptic distrubances.

在日本以东的西北太平洋，海面温度(SST)显示出一条跨越黑潮延伸(KE)的陡峭锋面。KE附近海温的季节梯度为5℃/2 0 0 km，海温变化较大。在这项研究中，我们在2005年7月(2006年1月)进行了全球定位系统(GPS)无线电探空大气探测，作为斯克里普斯海洋研究所(Bakuho-Maru，东京大学海洋研究所)(R/V)罗杰·雷维尔(Roger Revelle)号研究船的一次研究巡航。初夏，当KE地区的低层大气表现出天气扰动时，由于海洋的大惯性，SST锋面在巡航过程中有几个星期几乎是相同的。大气测深和测深仪测量分析表明，锋面上大气边界层的垂直结构发生了变化。当KE地区上空有暖湿(冷/干)气团时，在暖冷的海温上观察到云系由积云向低层云转变，偶有雾(由实心云层向云底较低的破碎层散布转变)。因此，主要的逆温层是在混层顶部形成的。混合层顶部(MLT)的时间变化主要与观测到的云底相对应，与地面热通量有很好的相关性。当通量超前MLT 5-12小时时，滞后相关达到最大值。天气风暴过后，地表热通量偶有超过800W·m~(-2)~(-2)·t~(-2)，从而在大气层中形成层云和层积云。这些观测结果表明，尽管上层大气表现出天气学上的不稳定性，但KE锋面上海温的空间变化对海洋大气边界层有一定的影响。