关键词: 微波辐射计, 水汽含量, 云液态水含量, 降水阈值

Abstract:

Based on the observation data of TP/WVP-3000 Microwave Radiometer from the Semi-Arid Climate Observatory and Laboratory of Lanzhou University, the characteristics of water vapor and cloud liquid water content before precipitation and during non-precipitation processes were analyzed in arid and semi-arid region in summer from 2007 to 2010. Results are as follows:(1) The value of water vapor content reached 2.20 cm can be used as a threshold of precipitation forecast in semi-arid area. When the water vapor content is greater than 2.20 cm within 24 hours before the rainfall and its variability rate reaches 0.06 cm/h, or the water vapor content is small at the beginning, and then exceeds 2.20 cm with the increase of variability of the water vapor content to 0.19 cm/h before the precipitation, which may be forecast precipitation in future. (2) The cloud liquid water content with 0.20 mm can be used as a threshold of precipitation forecast, and when it appears a turning-point before precipitation with time, subsequently the variability rate increases, which can be used to forecast precipitation after one hour.

Key words: microwave radiometer, water vapor content, cloud liquid water content, precipitation threshold