摘要
主要对0808号台风"凤凰"的登陆过程进行模拟试验。首先,利用GPS掩星资料反演的大气气压、温度和水汽资料以及云导风资料,对台风"凤凰"进行了三维变分同化及数值模拟试验。结果表明:同化不同资料,得到的台风初始场各不相同,对台风预报的影响也各不相同。同时同化GPS资料和云导风资料,对台风初始场的调整最大,对模拟台风登陆前后的路径、降水等均有一定程度的改善。其次,研究了资料同化中要素场调整的特征。发现初始场的调整在垂直方向上呈多峰结构,调整的显著性与资料有关也与要素有关,一般来说,低层的调整要大于高层。最后,利用同时同化GPS掩星与云导风资料的模拟结果,进一步分析这次台风过程的物理量场特征。发现:在模拟时段内,随着台风邻近大陆,水汽的源地由西南太平洋逐渐转变为南海。但自始至终存在着把丰富的水汽送入台风的水汽通道。在台风移动过程中,一直保持着强烈的上升运动,强的上升运动把低层暖湿空气向上输送,释放潜热为"凤凰"台风提供了发展的能源。
A numerical experiment is conducted on the landfall of typhoon Fung-wong（0808） mainly in this pa-per.First,GPS occultation refractivity data and cloud drift winds were used to initialize typhoon in WRF-Var sys-tem.The result of numerical simulation of Fung-wong shows that the initial structure and forecast of typhoon dif-fer with the different assimilated data.GPS occultation refractivity data and cloud drift winds assimilation,the ad-justment of which to the typhoon initial field is the biggest,can help provide the evolution of the track and precip-itation distributions reasonably.Second,the characteristics of the elements adjusted in the data assimilation was studied.It is found that the adjustment of the initial field is a multi-peak structure in the vertical direction,and the significance of the adjustment is related with the data and the element.Generally,low-level adjustment is larger than the top.Finally,a preliminary study has been also made on the mechanism of the sustaining of Fung-wong.During the forecast time,the sources of water vapor changes gradually from the south-west Pacific to the South China Sea when Typhoon nears the mainland,but there keeps a water vapor channel all the time,through which abundant water vapor was continuously transported to typhoon Fung-wong,and sustained vigorous ascending mo-tion,which transported the warm and moist air in the lower troposphere upwards to release latent heat and thus to provide kinetic energy for Fung-wong＇s sustaining.
出处
《海洋预报》
2011年第1期39-47,共9页
Marine Forecasts
基金
国家自然科学基金(4097503740775033)
关键词
GPS掩星资料
云导风
三维变分同化
台风模拟
物理量
GPS occultation refractivity data
cloud drift winds
three-dimensional assimilation
typhoon simulation
variables
