摘要
以高精度的气象观测资料为基础,用FAO推荐的FAO Penman-Monteith公式估算了黑河中游天然低湿牧草地的参考作物蒸散量(ET0)。结果表明:在一个完整年度内,试验地ET0为1 194.3 mm,日均3.26 mm.d-1。在牧草不同生长季节,ET0变化剧烈,非生长期、生长初期、生长中期、生长末期ET0分别为0.92,2.13,5.33 mm.d-1和2.52 mm.d-1,其蒸散量分别占全年蒸散总量的7.85%,5.02%,70.90%和16.23%。ET0在2月中下旬迅速增大,4月增大幅度最大,此后ET0进一步增大直到7月达到最大,随后ET0逐步减小,在11月中旬随着牧草生长期的结束降至年最低值。ET0在8:00时左右(生长中期在7:00左右)开始增大,13:00达到最大,18:00停止(生长中期在19:00左右)。
The study area （39°15＇043＂N, 100°03＇871＂E, 1 375 m a.s.l.） is located at Linze Ecology Station, Prataculture Ecology Institute, Lanzhou University, in Linze County, Gansu Province. It belongs to a temperate arid desert climatic zone, the annual precipitation is 116.8 mm, and the precipitation occurs mainly during the period from July to September, which occupies about 60% of the annual precipitation. The annual evaporation, however, is as high as 2 390 mm, and the aridity index is 15.9. The annual, maximum and minimum temperatures are 7.1℃, 39.1℃ and -27℃ respectively, the annual accumulated temperature 10℃ is 3 088℃, and the frost-free period is 168 days. The prevailing wind direction is NW, the annual average wind speed is 3.2 m/s, the days of occurring strong winds over force 8 are 15 days, the annual sunshine duration is 3 045 hours, and the annual solar radiation is 6 209.6 MJ/m^2. In this paper, the values of the reference evapotranspiration of herbages over a natural steppe （ET0） in the middle reaches of the Heihe River basin located in the Hexi Corridor of Gansu Province are estimated using the Penman-Monteith equation recommended by FAO based on meteorological data. The results show that the total reference evapotranspiration of the natural steppe is 1 194.3 mm during the period from September 2003 to August 2004, and the daily average is 3.26 mm. The values of ETo vary significantly from the different growing stages of herbages over the natural steppe. The values of ETo in the non-growing stage, early growing stage, middle growing stage and last growing stage of herbages over the natural steppe are 0.92 mm/d, 2.13 mm/d, 5.33 mm/d and 2.52 mm/d respectively, and their proportions occupy 7.85%, 5.02%, 70.90% and 16.23% of the annual ETo values respectively. Reference evapotranspiration of herbages over the natural steppe is sharply increased from mid-or late-February, especially in April, then it is further increased and to the maximum in July. From then on it is gradually decr
出处
《干旱区研究》
CSCD
北大核心
2005年第4期514-519,共6页
Arid Zone Research
基金
国家自然科学基金项目(40171002)
中日合作黑河流域水文过程研究项目资助
