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| Characteristics and simulation analysis of evapotranspiration of shrub sand dune at the oasis-desert transitional zones |
| Cui Xianghui1,2,3,Feng Qiang4,Wang Xuequan1,2,3 |
| 1.Research Institute of Forestry,Chinese Academy of Forestry;2.Key Laboratory of Tree Breeding and Cultivation,State Forestry Administration;3.China National Research and Development Center of Combating Desertification:100091;4.Beijing Forestry University,100083:Beijing,China |
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Abstract Evapotranspiration is one of the very important factors in water circulation and heat balance.Utilizing long-term observation and experimentation data,characteristics and changes of evapotranspiration shrub sand dune at the oasis-desert transitional zones were analyzed using Bowen-ratio methods;the relationship between evapotranspiration and meteorologic factors were explored.And then, evapotranspiration process in the Soil-Plant-Atmosphere Continuum were simulated with numerical simulation model.In the diurnal process of evapotranspiration, the occuring time of maximum evapotranspiration of Tamarix ramosissima and Nitraria tangutorum sand dune is earlier than that on the shifting sand dune.The order of maximum evapotranspiration rate is: Tamarix ramosissima sand dune(0.24 mm/h)>Nitraria tangutorum sand dune(0.20 mm/h)>shifting sand dune(0.18 mm/h).From July to September,the evapotranspiration of Nitraria tangutorum and Nitraria tangutorum were 69.3% and 65.4% of total evapotranspiration during the growing seasons.Through greycorrelation analysis,the main meteorologic factors effect on evapotranspiration were discovered,including sunlight,air temperature,air moisture stress,wind speed and so on;their correlative coefficients are 0.717,0.643,0.649 and 0.705 respectively.The preliminary results indicated that SPAC model is suitable for simulating and predicting evapotranspiration processes on the surface covered with different plants in arid and semi-arid area.
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Received: 28 July 2006
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