摘要
为了实现复杂地形下高分辨率风场的数值模拟及特征分析,采用中尺度气象模式WRF(Weather Research and Forecasting M odel)结合牛顿松弛逼近Nudging资料同化技术,实现哈密地区水平分辨率1 km的近地层风场数值模拟计算。基于模拟区域测风塔实测数据的对比检验发现,同化观测资料后风速风向的模拟结果均与实测更加接近,70 m高度风速模拟结果的绝对误差降低0. 25 m·s^(-1),同化后的模拟结果可以较好的修正风速较小时模拟值偏高和风速较大时模拟值偏小的问题,同时风廓线的模拟结果也与实测更加吻合。通过分析哈密复杂地形下水平分辨率1 km逐10 min风场输出结果发现:(1)哈密地区地形比较复杂,风速平面分布差异很大,4月份风速较大区域主要分布在山北地区和西部山南垭口附近,而7月份风速较大区域则位于西部的山坳南部和北部地区;(2)复杂地形下风速较小时风速为负切变,且平均风速越小负切变值越大,地形越复杂负切变值越大;风速较大即使是复杂地形下同样为正切变,但是正切变值比平坦地区的值要小,平坦地形下风速越大正切变值越大;(3)哈密地区复杂地形下,风速12～25 m·s^(-1)的风速占比在时间和空间上分布差异较大,风速较大的4月份,大部分地区占比达到20%以上,尤其是山北和西部垭口附近,占比甚至达到了50%以上,风速为12～25 m·s^(-1)的情况下80 m高度平均风速比60 m高0. 60～0. 80 m·s^(-1),比月平均风速的垂直变化值要大;(4)风速较大时,风向10 min变化不明显,风速较小时,风向变化值较大,且地形较平坦地区风向变化值较大,地形复杂地区变化值较小;(5)风向的垂直变化与风速大小关系比较明显,风速越小,其垂直变化越大,风向垂直变化的区域分布与地形复杂程度相关,地形越复杂风向的垂直变化值越大。
For numerical simulation and character of wind field with high resolution in complex terrain,mesoscale meteorological model WRF with data assimilation technology of nudging was used to realize numerical simulation of wind field with 1 km horizontal resolution in Hami area where terrain is very complex.By comparison with mast observation data,the simulation result after assimilation was close to observation data,the absolute error of wind speed simulation results decrease 0.25 m·s^（-1）.The simulation results corrected the problem that overestimate wind speed in breeze condition and underestimated in high wind condition.And simulation results of wind profile was also more consistent with observations.Through analysis of simulation results of wind field in Hami complex terrain by 1 km horizontal resolution with 10 min interval output,some conclusions were drawas the followings：（1） As terrain is very complex in Hami area,the wind speed distribution is very different.In April,the high wind area is mainly distributed in the north area of mountain and the pass area that is south of mountain in west region.While in July,the high wind area is located in the south area of pass in west region and north region.（2） Wind shear was negative in breeze condition under complex terrain,and the smaller the wind speed,the larger the negative shear value,and negative shear value was higher in more complex terrain.While in high wind condition,the vertical shear was positive even in complex terrain,but the positive value was less than that in flat area.And the positive value was greater with wind speed increasing in flat area.（3） The temporal and spatial distribution of the proportion in full-load wind condition was very different when wind speed is between 12 and 25 m·s^（-1） as terrain is complex in Hami area.The wind speed was high in April,the proportion of full-load wind speed was more than 20% in most areas,especially in north area and pass area in west region,the proportion was even more than 50%,the averag
作者
周荣卫
何晓凤
ZHOU Rongwei;HE Xiaofeng(China Meteorological Administration Public Meteorological Service Center,Beijing 100081,China)
出处
《高原气象》
CSCD
北大核心
2018年第5期1413-1427,共15页
Plateau Meteorology
基金
国家自然科学基金项目(41405012)
关键词
复杂地形
数值模拟
观测资料同化
风场特征
Complex terrain
numerical simulation
observation data assimilation
wind field character
