Meteorology#
Overview#
This section covers meteorology functions from NCL:
dewtemp_trh#
NCL’s dewtemp_trh calculates the dew point temperature given temperature and relative humidity using the equations from John Dutton’s “Ceaseless Wind” (pg. 273-274)[1] and returns a temperature in Kelvin
Important Note
To convert from Kelvin to Celsius-273.15 and to convert from Celsius to Kelvin +273.15
Grab and Go#
# Input: Single Value
from geocat.comp import dewtemp
temp_c = 18 # Celsius
relative_humidity = 46.5 # %
dewtemp(temp_c + 273.15, relative_humidity) - 273.15 # Returns in Celsius
6.298141316024157
# Input: List/Array
from geocat.comp import dewtemp
temp_kelvin = [291.15, 274.14, 360.3, 314] # Kelvin
relative_humidity = [46.5, 5, 96.5, 1] # %
dewtemp(temp_kelvin, relative_humidity) - 273.15 # Returns in Celsius
array([ 6.29814132, -35.12955277, 86.22114845, -27.40981025])
daylight_fao56#
NCL’s daylight_fao56 calculates the maximum number of daylight hours as described in the Food and Agriculture Organization (FAO) Irrigation and Drainage Paper 56 (Chapter 3, Equation 34) [2]
Grab and Go#
# Input: Single Value
from geocat.comp import max_daylight
day_of_year = 246 # Sept. 3
latitude = -20 # 20 Degrees South
max_daylight(day_of_year, latitude)
array([[11.66559195]])
# Input: List/Array
from geocat.comp import max_daylight
# Spring Equinox (March 20), Summer Solstice (June 20), Autumn Equinox (Sept. 22), Winter Solstice (Dec. 21)
days_of_year = [79, 171, 265, 355]
latitudes = 40 # Boulder
max_daylight(days_of_year, latitudes)
array([[11.92114937],
[14.84320154],
[11.92090136],
[ 9.15643116]])