def run_calcs(station, logfile, plots = False, diagnostics = False):
'''
Run the humidity calculations and add the attributes to the station file
:param object station: station object
:param file logfile: logfile to store outputs
:param boolean diagnostics: output diagnostic information
:param boolean plots: make a plot
:returns: station - updated with humidity variables
'''
temperatures = utils.apply_flags_to_mask(station, "temperatures")
dewpoints = utils.apply_flags_to_mask(station, "dewpoints")
# adjust from sea-level to station-level
station_pressure = get_station_level_pressure(station)
e_v = utils.set_MetVar_attributes("vapor_pressure", "Vapor pressure calculated w.r.t water", "water_vapor_pressure", "hPa", temperatures.mdi, np.dtype('float64'))
e_s = utils.set_MetVar_attributes("saturation_vapor_pressure", "Saturation vapor pressure calculated w.r.t. water", "water_vapor_pressure", "hPa", temperatures.mdi, np.dtype('float64'))
Tw = utils.set_MetVar_attributes("wet_bulb_temperature", "Wet bulb temperatures nearest to reporting hour", "wet_bulb_temperature", "C", temperatures.mdi, np.dtype('float64'))
q = utils.set_MetVar_attributes("specific_humidity", "Specific humidity", "specific_humidity", "g/kg", temperatures.mdi, np.dtype('float64'))
rh = utils.set_MetVar_attributes("relative_humidity", "Relative humidity", "relative_humidity", "%rh", temperatures.mdi, np.dtype('float64'))
# sort the vapour pressures and wet-bulb --> ice or water?
e_v.data, e_s.data, Tw.data = fix_wrt_ice_or_water(temperatures.data, dewpoints.data, station_pressure)
# get relative and specific humidity
q.data = calculate_q(e_v.data, station_pressure)
rh.data = calculate_rh(e_v.data, e_s.data)
if plots or diagnostics:
print "Humidity variables calculated, setting attributes\n"
else:
logfile.write("Humidity variables calculated, setting attributes\n")
setattr(station, "vapour_pressure", e_v)
setattr(station, "saturation_vapour_pressure", e_s)
setattr(station, "wetbulb_temperature", Tw)
setattr(station, "specific_humidity", q)
setattr(station, "relative_humidity", rh)
station = utils.append_history(station, "Humidity Calculations")
return station # run_calcs
def get_station_level_pressure(station):
'''
Convert from sea level pressure back to station level
List, R. J.: Smithsonian Meteorological Tables, Vol. 114, 6th Edn.,
Smithsonian Institution, Washington DC, 268 pp., 1963.
:param object station: station object
:returns: station level pressure (hPa)
'''
slp = utils.apply_flags_to_mask(station, "slp")
temperatures = utils.apply_flags_to_mask(station, "temperatures")
t_in_kelvin = temperatures.data + 273.15
elevation = station.elev
pressure = slp.data * np.ma.power(t_in_kelvin / (t_in_kelvin + 0.0065 * elevation), 5.625)
return pressure # get_station_level_pressure
