Variation Characteristics of Meteorological Elements near Surface Layer in North of the Taklimakan Desert

Based on the elements gradient observational data from automatic meteorological observation station from January to December 2011 in Hade in north of the Taklimakan Desert,the diurnal variation of wind speed,temperature and relative humidity near surface layer and the profile characteristics in four seasons were analyzed,firstly. Then,the atmospheric stability and surface roughness under neutral stratification were calculated. The results showed that the diurnal variation of temperature,relative humidity and wind speed from 0. 5 to 10 m near surface layer in Hade were obvious. The wind speed was high in the daytime and low at night,each layer wind speed reached the maximum value at 15: 00 and the minimum value at 04: 00,and the daily range was from 1. 1 to 1. 7 m / s. Each layer temperature increased to the maximum during 14: 00- 15: 00 and dropped to the minimum during 05: 00- 06: 00,the temperature difference was large between day and night,and the maximum temperature difference was 16. 5 ℃ which appeared in height of 0. 5 m. Moreover,there was significant temperature inversion from 17: 00 to 09: 00 in the next day. The relative humidity was between 25% and 55% in whole day,and the diurnal variation of relative humidity was opposite to temperature and wind speed. Among,the maximum value appeared at 06: 00,while the minimum value appeared at 15: 00. The profiles of wind speed,temperature,and humidity in four seasons near surface layer in Hade had an obvious change trend. The wind speed at 14: 00 in four seasons increased exponentially, and the variations of wind speed from 0. 5 to 2 m were greater than that from 2 to 10 m. The temperature in spring and summer rose mainly exponentially,while that in winter grew linearly,and there were obvious temperature inversion in four seasons. The relative humidity in winter was significantly higher than that in other seasons,and the profile in winter was more complex. The wind directions in Hade all year round mainly were the northeasterly wind,and the dominant wind directions in height of 2 and 10 m were consistent,but the wind frequencies were slightly different. Furthermore,the aerodynamic roughness under neutral stratification condition in Hade was from 1. 42 × 10- 11to 1. 7 × 10- 3m,and the mean value was 4. 2 × 10- 5m.