成都地区秋、冬季GPS可降水量的时空分析

利用成都地区5个测站地基GPS2007年9月-2008年2月的观测数据,解算出1 min间隔的天顶总延迟,结合自动气象站资料计算出30 min间隔的大气可降水量(GPS-PWV).对月平均的GPS-PWV分析表明:秋、冬季变化趋势从9月开始下降,1月达到最小值,2月又逐渐上升.在大气环流相同的情况下,地理位置相近的站,海拔高的地区大气中的水汽量比海拔低的地区要少,且变化较大;海拔高度相近的站,大气中的水汽含量由南向北减少.日合成分析显示:在静稳天气下,日变化特征显著,具有双峰型特征:白天峰值与气温的最大值相对应;夜间峰值与降水量的峰值相对应;GPS-PWV与地面空气相对湿度白天呈负相关,夜间呈正相关.

On the spatial-temporal analysis of GPS precipitable water vapor in autumn and winter in Chengdu Plain

The estimates of total zenith delay are available based on GPS data per 1min from the ground-based GPS network in Chengdu plain during the period of September 2007 to February 2008. The estimates of every 30 min precipitable water vapor (PWV) derived from GPS are obtained by combining meteorological data from automatic weather stations. By analyzing monthly GPS-PWV of five stations in Chengdu plain it shows that the monthly GPS-PWV ascend after first descending, namely it starts to descend from September, to reach minimum in January, then to ascend in February. While the stations are close and in the same circulation, the monthly value of GPS-PWV with high altitude is lower than the low altitude; the variation of GPS-PWV is more evident at the high altitude. When the altitude is similar, GPS-PWV reduces from south to north. The diurnal variations of GPS-PWV and some surface meteorological elements are composite during the cold season at Chengdu station. The feature of diurnal variation of GPS-PWV at Chengdu station is obvious: it is a bimodal curve. The peak value of GPS-PWV in the daytime is corresponding to the maximum value of temperature and it is relative to the peak of precipitation in the night. Though the relationship between GPS-PWV and relative humidity of surface atmosphere in the daytime is negative correlation, it is positive correlation in the night.