Abstract: In this paper, the comparative analyses were carried out to research the profiles of temperature and relative humidity using the retrieval data with the microwave radiometer (MWR) and sounding in Urumqi in summer 2008. The results show that the correlation coefficients of temperature and relative humidity were 0.99 and 0.85 respectively, which revealed that the holistic trend of temperature and relative humidity was significantly similar. The [WTBX]PWV[WTBZ] revealed that there was a diurnal cycle with an amplitude of 1.55 mm and fluctuation of 7.1%, it was decreased gradually from 04:00 to 15:00 [JP8]o’[JP]clock but increased gradually from 15:00 to 23:00, and its average, maximum and minimum values were 21.66 mm, 22.44 mm and 20.89 mm respectively. The highest and lowest [WTBX]PWV[WTBZ] values, 23.43 mm and 19.78 mm, occurred in July and August, respectively. The increased [WTBX]PWV[WTBZ] rate was symmetrical with the decreased one. The precondition of rainfall was that the [WTBX]PWV[WTBZ] should exceed a threshold value, which was 27 mm in Urumqi in summer, and the distribution of rainfall intensity and [WTBX]PWV[WTBZ] should be synchronous in terms of time in Urumqi.

Key words: microware radiometer, water vapor, rainfall, diurnal cycle, sounding profile, Urumqi