黑河流域1960-2009年平均风速时空变化特征

Temporal and Spatial Characteristics of Average Wind Speed Changes in Heihe River Basin from 1960 to 2009

利用黑河流域气象站点19602009年的逐月、逐年的风速观测资料，运用Mann-Kendall检验法和反距离加权插值法（IDW）及相关分析法对黑河流域平均风速时空变化特征进行了分析。结果表明，近50a来黑河流域年平均风速呈减小趋势，其变化趋势指标口值为-0．01；春、夏、秋、冬季平均风速均表现为下降趋势，口值分别为-0．012，-0．011，-0．007和-0．008。年代际变化在60-70年代为正距平，80年代以后为负距平。年内变化表现为偏双峰型，第1峰值远大于第2峰值，分别出现在4月和11月。空间变化上，上游山区年平均风速呈上升趋势，平均每年增加0．01m／s；中游和下游均表现为下降趋势，降幅在0．005-0．029m／s，同时在不同季节空间差异明显。年平均风速突变发生在1985年左右，春、夏、秋、冬季突变分别出现在1986，1984，1983和1985年。年、春季风速下降与平均气温、平均最低／最高气温以及潜在蒸散有关，夏、秋季平均最高气温的影响变小，而冬季仅有潜在蒸散通过了0．01的显著性检验，说明风速下降是造成黑河流域冬季潜在蒸散量减小的主要因素。

Monthly and annually wind speed data from nine meteorological stations over Heihe River Basin, observed by the China Meteorological Administration from 1960 to 2009, were used to analyze the spatial and temporal variability of average wind speed. Mann--Kendall methods, inverse distance weighted （IDW）, and correlation analysis were employed. The result showed a decreasing trend in annual average wind speed during the past 50 years, and the/9 value was --0.01. Decreasing tendency in wind speed occurred in four seasons（spring, summer, autumn and winter） as well, and the/？ values were -- 0. 012, -- 0.011, -- 0. 007 and --0. 008, respectively. Interdecadal change of wind speed in the 1960s and 1970s showed positive anoma- lies, while a negative anomaly was showed since 1980s. The intra-annual variation of wind speed appeared as partial bimodal. Meanwhile, these two peaks existed in April and November, respectively, and the first peak was much larger than the second one. Spatially, slightly increasing trend was showed in the upper reaches with an average rate of 0.01 m/s, while decreasing trend were showed in the middle and lower reaches with an average rate of 0. 005 and 0. 029 m/s, respectively. At the same time, the trends in different regions var- ied significantly in four seasons. Abrupt change in annual wind speed occurred in 1985, while abrupt change in four different seasons occurred in 1986, 1984, 1983 and 1985, respectively. Decreasing trend in annual and spring wind speed was correlated with average temperature, average maximum temperature, average mini- mum temperature and potential evapotranspiration, but this correlation declined in summer and autumn. Only potential evapotranspiration in winter affected wind speed significantly at the 0.01 level. All this indicated that, decreased wind speeds was the main factor that leading to the decrease of Potential evarmtransnipirtion in Heihe River Basin in recent 50 years.