import metpy.calc as mpcalc
dewpoint = mpcalc.dewpoint_from_relative_humidity(t,RH)
thetae=mpcalc.equivalent_potential_temperature(p,t,dewpoint)#相当位温
垂直速度Pa/s转换为m/s
需要传入三个参数：压力坐标系下的垂向速度ω、压力p、气温t，混合比（默认为0）
metpy.calc.vertical_velocity(omega, pressure, temperature, mixing_ratio=0)
omega (pint.Quantity) – Vertical velocity in terms of pressure
pressure (pint.Quantity) – Total atmospheric pressure
temperature (pint.Quantity) – Air temperature
mixing_ratio (pint.Quantity, optional) – Mixing ratio of air
