wradlib安装问题

灰色节能君

费力好大的劲安装了雷达处理的模块包wradlib，导入时模块时没出问题，照着官网的例子调用的时候出了问题，报错如下Traceback (most recent call last):
  File "D:/PyCharm 5.0.3/untitled2/雷达/wrad_test.py", line 12, in <module>
    filename = wrl.util.get_wradlib_data_file('dx/raa00-dx_10908-0806021655-fbg---bin.gz')
  File "D:\python\lib\site-packages\wradlib\util.py", line 579, in get_wradlib_data_file
    data_file = os.path.abspath(os.path.join(get_wradlib_data_path(), relfile))
  File "D:\python\lib\site-packages\wradlib\util.py", line 571, in get_wradlib_data_path
    raise EnvironmentError("'WRADLIB_DATA' environment variable not set")
OSError: 'WRADLIB_DATA' environment variable not set


我想主要是最后一句，这个WRADLIB_DATA要怎么设置环境变量啊，求大神解答