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利用北京、哈尔滨、广州等8个大型城市气象站1985~2014年地面风速定时观测资料、同期再分析资料(NCEP1)以及城市规模指标,每5年为一时间段,分析不同时段风速Weibull分布各参数(k,c,r)的变化及其与城市扩展规模之间的关系.结果表明:(1)风速概率分布参数变化程度与城市规模扩展速度有关;城市化效应使得位置参数r变化最大,尺度参数c次之,而形状参数k变化趋势不明显.(2)尺度参数c随城市建成区面积的增加呈现线性递减趋势,7个站的回归方程通过检验,变化率在-0.0203~-0.0016 km~(-2)之间,意味着随城市规模扩大,风速概率密度曲线分布幅度收窄.(3)位置参数r随建成区面积的增加表现为线性上升趋势,数值由负到正变化,6个站回归方程通过检验,变化率在0.0014~0.0171 km~(-2)之间,意味着城市规模扩大会导致静风、微风频率减小.分析还显示r的变化率与纬度相关良好.(4)以再分析资料拟合参数c_x和r_x,取相对变量c/c_x和r/r_x以表征城市化效应对风参数的影响部分,分析的结果与c,r相似.(5)形状参数k与城市规模指标的相关不显著.
Based on the observed data of surface wind velocity from 8 large meteorological stations in Beijing, Harbin and Guangzhou from 1985 to 2014, the same period reanalysis data (NCEP1) and urban size indicators, the Weibull distributions at different time intervals (K, c, r) and its relationship with the scale of urban expansion.The results show that: (1) the degree of change of wind speed probability distribution parameter is related to the expansion speed of urban scale; the urbanization effect makes the maximum change of location parameter r, The scale parameter c is second, while the shape parameter k is not obvious. (2) The scale parameter c decreases linearly with the increase of urban built-up area. The regression equation of seven stations is tested, the rate of change is -0.0203 ~ -0.0016 km ~ (-2), which means the distribution of wind speed probability density decreases with the increase of city size. (3) The position parameter r shows a linear upward trend with the increase of the built-up area, and the value changes from negative to positive. The regression equation of 6 stations is tested, and the rate of change is between 0.0014 ~ 0.0171 km ~ (-2), which means that the increase of urban size leads to the quiet wind and the decrease of the breeze frequency.The analysis also shows that the rate of change of r is well correlated with latitude. (4) to re-analysis The data fitting parameters c_x and r_x, take the relative variables c / c_x and r / r_x to characterize the impact of urbanization on the wind parameters. The results of the analysis are similar to c and r. (5) The shape parameter k and the urban scale index The correlation is not significant.