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.

在日本以东的北太平洋西部，海面温度（SST）显示出横跨黑潮延伸带（KE）的陡峭锋面。 KE附近的海温梯度为5℃/200 km，季节变化较大，因此该地区海温变化较大。在本研究中，我们于 2005 年 7 月（2006 年 1 月）作为斯克里普斯海洋学研究所的罗杰·雷维尔研究船（R/V Hakuho-maru，东京大学海洋研究所）的研究巡航，对锋面进行了全球定位系统（GPS）无线电探空仪大气探测。初夏，当覆盖 KE 区域的低层大气表现出天气扰动时，海温锋面由于海洋的巨大惯性，航行期间的几个星期几乎没有变化。大气探测和云高仪测量的分析表明，大气边界层的垂直结构在锋面发生了变化。在暖/湿（冷/干）气团上覆KE区域的情况下，在暖海温到冷海温的范围内观察到云态从积云转变为低层层云，偶尔转变为雾（从具有坚实云层的层云到具有较低云底的破碎层云）。在深冬，由于温暖的海洋和凉爽/干燥的大气，近地表总是不稳定。因此，主要反转形成在充分混合层的顶部。混合层顶部（MLT）的时间变化主要对应于观测到的云底，与地表热通量密切相关。当通量超前 MLT 5-12 小时时，滞后相关性变得最大。经过一次天气风暴后，地表热通量偶尔会超过800W m^-2>，从而在MLT处形成层云和层积云。这些观测结果表明，尽管上覆大气显示出天气扰动，但海洋大气边界层仍受到KE锋面海温空间变化的修正。