新疆策勒沙漠-荒漠-绿洲典型下垫面小气候空间变化分析

Spatial Analysis on Changes of Microclimate in Typical Landscapes in Desert-Wilderness-Oasis in Cele,Xinjiang

利用从2010年8月1日至2011年6月30日新疆策勒绿洲-荒漠过渡带及绿洲内部4个观测点的风速、大气相对湿度(RH)、温度、太阳辐射能、光合有效辐射(PAR)同步观测资料,分析了小气候差异并初步探讨产生差异的原因。结果表明:不同空间的下垫面性质对小气候影响明显不同。在8月,半固定沙地、固定沙地和绿洲内部与流沙地前沿相比,日平均风速在2 m高处分别依次降低了42.69%、50.71%和94.32%,日平均风速在10 m高处分别依次降低了7.94%、13.66%和59.59%,这表明植被覆盖度越大,防风阻沙效果越好。夏季植被能够降温增湿,冬季12月份,绿洲内部在0.5 m高处日平均温度依次高于流沙地、半固定沙地、固定沙地1.47℃、1.20℃、2.74℃。4个下垫面的PAR与太阳辐射能变化趋势基本一致,绿洲内部的PAR值相对最小,太阳辐射能在6月达到最高值。夏季晴天在20:00~09:00左右近地表层会出现逆温现象。冬季晴天白天午后易出现大于起沙风的阵风,从流沙前沿到绿洲内部气温逐渐升高,大气相对湿度先逐渐降低后增大。

The comparison and analysis of the wind velocity, air temperature, relative humidity （RH）, photosyn- thetically active radiation （PAR） and solar radiation at the four meteorological stations were made based on synchronous observation in oasis-desert ecotone and oasis in Cele from 1 August, 2010 to 30 June, 2011. The microclimate differences were analyzed and the reasons for variability were discussed preliminarily. The results show that during August, the daily wind velocity at the height of 2 m in semi-fixed sandy land, fixed sandy land and inner oasis was 42.69%, 50.71% and 94.32% less than that in shifting sandy land, wind velocity at the height of 4 m was 31.7%, 39.25% and 73.64% less than that in shifting sandy land, wind velocity at the height of 10 m was 7.94%, 13.66% and 59.59% less than that in shifting sandy land, which shows that the ef- fects of wind prevention and sand resistance would be better with the increased vegetation cover. The air tem- perature can be slowed down and the humidity would be increased by plants. In December, the daily temperature at the height of 0.5 m in oasis was higher than shifting sandy land, semi-fixed sandy land and fixed sandy land by 1.47℃, 1.2℃ and 2.74℃. The changing trends for PAR and solar radiation are basically agree in the four landscape types, PAR is the smallest in oasis in four sites, solar radiation was highest in June. In a fine day in summer, there is a phenomenon by temperature inversion near the ground surface between 20：00 and 09： 00 at night. In a fine day in winter, gust wind more than sand-driving wind is more likely to arise after the noon in the day. The air temperature decreased gradually from shifting sandy land to oasis, while the PAR first in- creased and then decreased gradually.