Observational Study on the Diurnal Variation in Precipitable Water Associated with the Thermally Induced Local Circulation over the"Semi-Basin"around Maebashi using GPS Data
Observational Study on the Diurnal Variation in Precipitable Water Associated with the Thermally Induced Local Circulation over the"Semi-Basin"around Maebashi using GPS Data
复制标题
利用GPS数据对前桥周边“半盆地”热致局地环流相关的降水量日变化观测研究
DOI：
10.2151/jmsj.79.1077
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发表时间：
2001
影响因子：
3.1
通讯作者：
Takahiro Miki
中科院分区：
文献类型：
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作者：
H. Iwasaki;Takahiro Miki
利用GPS和无线电探空资料研究了“半盆地”上空可降水量的日变化过程。半盆地上空的可降水量具有明显的日变化，最大值在18-20 JST附近，日较差为10 - 25 mm。可降水量的变化与地面风的ESE分量的变化一致，这是由于热力引起的局部环流。水汽的日变化存在两个不同的层：L层（地表至1.5 km）和H层（1.5 km至3.0 km）。在上升期（09：00 ~ 20：00 JST），关东北部山区南部的可降水量同时上升。L层可降水量的变化在很大程度上受地面风辐合的控制。此外，位于山脉背风侧的半盆地H层的水汽量从傍晚到午夜突然增加。预计由于热诱导的局地环流而被输送到山区的水汽通过环境风和/或回流进入半盆地，并且水汽平流导致半盆地上方H层水汽增加。在降水量减少期（21：00 ~ 08：00 JST），可降水量在整个GPS网范围内均呈显著减少趋势。水汽的减少与H层位温的增加相一致。太平洋高压的大范围下沉是半盆地可降水量日变化显著的必要条件。
The processes associated with the diurnal variation of precipitable water over the “semi-basin” were studied using GPS and radiosonde data. Precipitable water over the semi-basin exhibited a pronounced diurnal variation, with a maximum around 18-20 JST and a diurnal range of 10 to 25 mm. The variation of precipitable water agreed well with the variation of ESE component of the surface wind, due to a thermally induced local circulation. The diurnal variation of water vapor was recognized in two different layers of Layer L (surface to 1.5 km), and Layer H (1.5 km to 3.0 km). In the increasing period (09:00 to 20:00 JST), precipitable water increased simultaneously all over the south part of the mountains in the north Kanto District. The variation of precipitable water in the Layer L would be, in large part, controlled by convergence of surface wind. Furthermore, the amount of water vapor in Layer H over the semi-basin that is located on the lee side of mountains increased abruptly from evening to midnight. It was expected that the water vapor that had been transported into the mountains due to the thermally induced local circulation traveled into the semi-basin by ambient wind and/or return flow, and the moisture advection caused the increase of water vapor in Layer H over the semi-basin. In the decreasing period (21:00 to 08:00 JST), precipitable water decreased simultaneouly all over the GPS network using the present study. The decrease in water vapor coincided with increase in potential temperature in the Layer H. The large scale subsidence due to the Pacific High seemed to be necessary for the prominent diurnal variation of precipitable water over the semi-basin.
DOI：
--
发表时间：
2021
期刊：
影响因子：
--
作者：
Tabata Naoya;Vrij Aldert;吉川肇子・中村美枝子・杉浦淳吉;西田公昭;太幡直也;森永康子・村上理子・本勝仁士・川田遥子・木本ゆき;西田公昭
通讯作者：
西田公昭