基于高分辨率模式的京津冀地区无人机航路风向风速模拟分析

随着中国低空空域的陆续开放,依靠现有的低空飞行气象保障技术为低空安全飞行提供服务略有不足,对飞行影响最大的风进行预报也有一定的困难。论文基于WRF(Weather Research and Forecasting Model)中尺度数值模式,对2015—2019年京津冀地区的风速风向进行模拟,并将模拟结果与气象站观测数据进行对比分析,可为该地区无人机低空航路飞行安全提供保障。结果表明:WRF模式能够较好地模拟风速的季节变化趋势,平原地区的模拟效果优于山区,山区模拟的风速偏大,但误差在可接受的范围内(RMSE<1.5 m·s^-1)。平均风速、最大风速最小值均出现在夏末,平均风速最大值出现在春季(山区4.43 m·s^-1、平原4.13 m·s^-1);最大风速在冬、春、夏初呈波动递增,夏季中旬开始减少,夏末秋初降至最小。京津冀地区风速呈西北向东南递减,泊头站(-0.02 m·s^-1·(5 a)^-1)和天津站(-0.02 m·s^-1·(5 a)^-1)平均风速呈下降趋势,其余站点风速呈上升趋势,唐山站上升率最大(0.08 m·s^-1·(5 a)^-1);在风速季节空间分布中,平均风速以上升趋势为主,站点所占比例为春季45.45%、夏季90.91%、秋季63.63%、冬季81.81%。平原地区盛行风呈东北—西南向;山区站点怀来站风向以WNW(18.70%)和W(15.01%)为主,蔚县站风向以N(16.79%)和NNW(12.03%)为主,相较于平原地区,山地地区风速8.0 m·s^-1的大风数量显著上升。1000 m高度的平原地区大风出现频率显著增加,增长速度高于山地地区,不利于无人机飞行,风速17.0 m·s^-1以上出现的概率明显高于山地地区。

Simulation and analysis of wind speed and direction of unmanned aerial vehicle route in the Beijing-Tianjin-Hebei region based on high resolution model

With the continuous opening of China's low-altitude airspace, relying on the existing low-altitude flight weather support technology to provide services for low-altitude safe flight is to some extent insufficient, and it is also difficult to forecast wind speed that has the greatest impact on flight. Based on the Weather Research and Forecasting (WRF) model mesoscale numerical model, this study simulated the wind speed and direction in the Beijing-Tianjin-Hebei region from 2015 to 2019, then compared the simulation results with the observation data of the weather stations in order to provide simulation tools for the safety of drones flying on low-altitude routes in the region. The main conclusions are as follows: the WRF model can better simulate the seasonal trend of wind speed, the simulation result in the plain areas is better than in the mountainous areas, and the simulated wind speed in the mountainous areas is higher than the observed data but the error is within an acceptable range (RMSE<1.5 m·s^-1). The minimum values of average wind speed and maximum wind speed both appear in the late summer, and the maximum average wind speed appears in spring (4.43 m·s^-1 in the mountainous areas, 4.13 m·s^-1 in the plain areas). The maximum wind speed fluctuates and increases in winter, spring, and early summer, begins to decrease in mid-summer, and decreases to a minimum in late summer and early autumn. Wind speed in the Beijing-Tianjin-Hebei region is decreasing from northwest to southeast, the average wind speed at Potou Station (-0.02 m·s^-1·(5 a)^-1) and Tianjin Station (-0.02 m·s^-1·(5 a)^-1) showed a downward trend, the wind speed at other stations showed an upward trend, and Tangshan Station has the largest increase rate (0.08 m·s^-1·(5 a)^-1). With regard to the seasonal spatial distribution of wind speed, the average wind speed is mainly on the rise, and the station proportions are 45.45% in spring, 90.91% in summer, 63.63% in autumn, and 81.81% in winter. The prevailing wind in the plain areas is northeast-southwest; the wind direction of Huailai Station in the mountainous area is mainly in WNW direction (18.70%) and W direction (15.01%), while the wind direction of Yuxian Station is mainly in N (16.79%) and NNW (12.03%). Compared with the plain areas, the number of strong winds with wind speed of 8.0 m·s^-1 has increased significantly in the mountainous areas. At a height of 1000 m, the frequency of strong winds in the plain areas increased significantly and the growth rate was higher than in the mountainous areas, which is not conducive to UAV flight, and the probability of occurrence of wind speeds above 17.0 m·s^-1 is also significantly higher than in the mountainous areas.