Abstract: Based on the meteorological data in the surface layer of grassland in the north shore of Qinghai Lake from May to December in 2006 observed by Haibei Animal Husbandry Meteorological Experimental Station, the characteristics of changes of the diurnal variation and the vertical profiles of the wind speed, temperature and humidity were investigated. The results showed that the wind speed, temperature and relative humidity showed an obvious diurnal variation above 0.3m and below 10m in the surface layer of grassland in the north shore of Qinghai Lake. The phase of the maximum and minimum temperature delayed with the increase of the height and the phase of the maximum and minimum relative humidity and wind speed advanced with the increase of the height. The temperature at fourteen o'clock decreased with the increase of the height and the temperature at twenty o'clock increases first and decreased later with the increase of the height. The temperature profiles had an inflexion at the height of 4m, then into the status of the inversion. The degree of the inversion reached biggest at eight o'clock. Relative humidity decreased and wind speed increased with the increase of the height whenever day and night.

Key words: Meteorological factors, Meteorological factors, Diurnal variation, Characteristics of profiles, Surface layer