""" Created April 15, 2015 Collection of functions to calculate various physical parameters @author: Scott Havens """ import numpy as np from smrf.envphys import thermal_radiation [docs]def idewpt(vp): """ Calculate the dew point given the vapor pressure Args: vp - array of vapor pressure values in [Pa] Returns: dewpt - array same size as vp of the calculated dew point temperature [C] (see Dingman 2002). """ # ensure that vp is a numpy array vp = np.array(vp) # take the log and convert to kPa vp = np.log(vp/float(1000)) # calculate the vapor pressure Td = (vp + 0.4926) / (0.0708 - 0.00421*vp) return Td [docs]def rh2vp(ta, rh): """ Calculate the vapor pressure given the air temperature and relative humidity Args: ta: array of air temperature in [C] rh: array of relative humidity from 0-100 [%] Returns: vapor pressure """ if rh.flat[0] >= 1.0: rh = rh/100.0 satvp = thermal_radiation.sati(ta + 273.15) return satvp * rh [docs]def satvp(dpt): """ Calculate the saturation vapor pressure at the dew point temperature. Args: dwpt: array of dew point temperature in [C] Returns vapor_pressure """ return thermal_radiation.sati(dpt + 273.15)