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王慧, 胡泽勇, 马伟强, 等. 鼎新戈壁下垫面近地层小气候及地表能量平衡特征季节变化分析[J]. 大气科学, 2008, 32(6): 1458-1470. DOI: 10.3878/j.issn.1006-9895.2008.06.19
引用本文: 王慧, 胡泽勇, 马伟强, 等. 鼎新戈壁下垫面近地层小气候及地表能量平衡特征季节变化分析[J]. 大气科学, 2008, 32(6): 1458-1470. DOI: 10.3878/j.issn.1006-9895.2008.06.19
Wang Hui, Hu Zeyong, Ma Weiqiang, et al. The seasonal variation of microclimate characteristics and energy transfer in the surface layer over Dingxin Gobi[J]. Chinese Journal of Atmospheric Sciences, 2008, 32(6): 1458-1470. DOI: 10.3878/j.issn.1006-9895.2008.06.19
Citation: Wang Hui, Hu Zeyong, Ma Weiqiang, et al. The seasonal variation of microclimate characteristics and energy transfer in the surface layer over Dingxin Gobi[J]. Chinese Journal of Atmospheric Sciences, 2008, 32(6): 1458-1470. DOI: 10.3878/j.issn.1006-9895.2008.06.19

鼎新戈壁下垫面近地层小气候及地表能量平衡特征季节变化分析

The seasonal variation of microclimate characteristics and energy transfer in the surface layer over Dingxin Gobi

  • 摘要: 利用在甘肃酒泉金塔地区进行的 “绿洲系统能量与水分循环过程观测与数值研究” 野外试验中的鼎新戈壁下垫面近地层2年的微气象观测资料, 分析了鼎新戈壁下垫面近地层小气候和能量平衡特征的季节变化规律。结果表明: 鼎新戈壁地区四季的平均风速在2~6 m/s之间, 没有明显的地方性风, 局地环流和局地相互作用可忽略; 冬季8 m向上比湿梯度垂直减小, 其他季节接近等比湿分布。7月, 典型晴天天气下, 能量平衡各量表现出标准的日循环形态, 白天感热通量峰值达到574 W/m2, 地热流量峰值为101 W/m2, 潜热很小, 在夜间和正午时刻存在负水汽输送现象; 然而降水天气下, 地气之间能量传输却以潜热蒸发为主, 感热很小, 地热流量为负值; 无论晴天和阴天, 地表和浅层 (5 cm和10 cm) 土壤温度都表现为准正弦曲线变化; 与敦煌戈壁相同, 土壤温度的活动层基本在10 cm范围以内, 40 cm以下地温已不存在日变化特征; 降水天气下, 地表和浅层土壤温度有随时间减小的趋势。能量平衡各分量均具有明显的季节变化规律, 感热通量季节平均的峰值在250~400 W/m2之间, 在夏季最大, 冬季最小; 潜热通量季节平均的最大值只有15 W/m2; 地气之间能量传输全年都以感热输送为主; 云和降水使夏季能量平衡各分量与晴天相比减少25%左右, 这种影响程度比极端干旱的敦煌荒漠戈壁地区稍大, 而小于半干旱的陇中黄土高原地区。另外, 在这一地区干旱情况很严重, 夏季的Bowen比极值达到62.4, 季节平均值也高达16.5。

     

    Abstract: By using the field data during the “Oasis System Energy and Water Cycle Field Experiment” in the surface layer over Dingxin Gobi in Jinta County of Jiuquan, Gansu Province, the characteristics of micrometeorological and energy budget are studied. Following conclusions are obtained based on the studies. The seasonal variation of wind velocity is weak with its average value being between 2 m/s and 6 m/s in four seasons, and there is no obvious effect of local wind, so the local circulation and local interaction can be ignored. The vertical gradient of specific humidity decreases with height above 8 m in winter. However, it changes little in other seasons and expresses an isentropic distribution. The peak values of sensible heat flux and soil heat flux reach 574 W/m2 and 101 W/m2, respectively, and the latent heat flux is very small in the typical clear-sky day of July. But for the heat exchange processes between land and air in rainy days, the latent heat flux is great, the sensible heat flux is small, and the soil heat flux is negative. There is a phenomenon of negative water-vapor transfer in the afternoon and at night. The surface and shallow-layer (5 cm and 10 cm) soil temperatures present accurate sine curve changes regardless of clear-sky days and overcast days. The soil temperature active layer is in the 10 cm scope, and there are no diurnal variation characteristics below 40 cm, which is the same as Dunhuang Gobi. The surface and shallow-layer soil temperatures have the tendency of reducing with time under the precipitation weathers. Each component of surface energy balance shows obvious seasonal variation. The peak value of sensible heat flux reaches 250-400 W/m2 on the average, and it is biggest in summer and smallest in winter. The seasonal mean maximum of latent heat flux is less than 15 W/m2. So the primary component of heat exchange processes between land and air is sensible heat in a whole year. The cloud and precipitation cause about 25% disturbances to each component of energy balance in the studied area, which is slightly higher than that in Dunhuang Gobi and much lower than that in the loess plateau of middle Gansu Province. Furthermore, the arid situation is very serious in this region, the peak value of Bowen ratio is 62.4 and the seasonal mean value is 16.5 in summer.

     

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