Abstract:

The comparison and analysis of the wind velocity， air temperature， relative humidity， solar radiation， photo-synthetically active radiation and wind direction at the eight meteorological stations were made based on synchronous observation data in Cele from 1 October， 2010 to 30 September， 2011. The characteristics of spatial microclimate differences in different underlying surfaces were analyzed and the reasons for variability were discussed. The results showed that： （1） The daily average wind velocity at the height of 3 m in grassland station， farmland 1， and big county station was 65.58%， 63.88% and 73.24% less than that in Rewake. The daily average wind velocity at the small bazaar is always the smallest at height of 2 m and 4 m. The monthly average wind velocity inside the oasis is lower than the outside of the oasis. The main wind directions of mobile sandy land， semi-fixed sandy land， and fixed sandy land are mainly WNW， ESE and W and the wind is relatively stable， while the wind direction at other observation stations is more scattered. （2） During the observation period of nearly 12 months， the average temperature inside the oasis was lower than that outside the oasis， and the effect of warmer in winter and cooler in summer was obvious. The average temperature in January winter from low to high are followed by mobile sandy land， semi-fixed sand， fixed sandy land， farmland1， grassland station， small bazaar， Rewake， big county， respectively -10.39， -10.25， -10.08， -9.56， -9.25， -9.19， -8.74， -8.71 ℃， the average temperature in August summer from high to low in turn into mobile sandy land， semi-fixed sand， fixed sandy land， Rewake， grassland station， farmland1， small bazaar， big county， respectively. Which was 26.55, 26.11， 25.41， 25.09， 24.06， 22.89， 22.36 and 22.33 ℃. （3） The daily relative humidity of semi-fixed sandy land， fixed sandy land， Rewake， grassland station， big county， small bazaar and farmland1 at the height of 2 m was increased by 0.29%， 6.67%， 7.94%， 14.37%， 28.99%， 30.39% and 30.69%， respectively， compared with that of mobile sandy land. The spatial difference of the monthly average relative humidity of different underlying surfaces， which is similar with the daily average change. （4） During the observation period of nearly 12 months， the change trends of solar radiation and the PAR are generally consistent. The daily and monthly average solar radiation energy and PAR of semi-fixed sandy land are always the highest. The overall solar radiation and PAR in oasis-desert ecotone are higher than those inside the oasis. （5） During the spring sandstorm days， the average wind velocity in semi-fixed sand， fixed sandy land， small bazaar was 25.75%， 27.05%， and 46.93% less than that in mobile sandy land. The average wind velocity of Rewake， grassland station， farmland 1， big county were 3.12， 1.38， 1.38 and 0.93 m·s^-1， and the average temperature and humidity， solar radiation and PAR inside the oasis are generally higher than those outside the oasis. Oasisization in the oasis has a strong effect on the local microclimate， so on the sandstorm days in spring， the effect of increasing temperature and humidity inside the oasis is relatively well. The longer the reclamation period of the oasis was， the greater the vegetation coverage was， and the more significant the effect of cooling and humidification was in summer.

Key words: oasisfication, oasis-desert ecotone, microclimate, vegetation coverage, Cele County