Atmosphere

absolute_airmass(relative_airmass, pressure)

Computes the absolute airmass [12].

altitude2pressure(altitude)

Computes the site pressure from local altitude.

It follows the same assumption of pressure2altitude.

aod_bb_hulstrom1980(aod380, aod500)

Computes the approximate broadband aerosol optical depth (AOD), as proposed in [13, 14].

It correlates broadband AOD using two wavelengths, 380 nm and 500 nm, denoted with aod380 and aod500, respectively.

apparent_vapor_scale_height_gueymard94(air_temperature)

Computes the apparent water vapor scale height [km] as proposed in [15, Eq. 4].

linke_turbidity_kasten1996(absolute_airmass, precipitable_water, aod_bb)

Computes the Linke turbidity using Kasten pyrheliometric formula.

Note that broadband aerosol optical depth (AOD) can be approximated by AOD measured at 700 nm according to Molineaux [16]. Bird and Hulstrom offer an alternate approximation using broadband aerosol optical depth (aod_bb), measured at 380 nm and 500 nm. Based on original implementation by Armel Oumbe. Note that these calculations are only valid for absolute_airmass less than 5 and precipitable_water less than 5 cm.

linke_turbidity_meteotest(location::Location, datetime::DateTime)

Computes the Linke turbidity based on SoDa [17, 18].

It performs a bilinear interpolation of the Linke turbidity array, for the corrsponding latitude, longitude, and month values. In such an array, rows represent global latitudes, columns represent global longitudes, and depth (third dimension) represents months of the year.

precipitable_water_gueymard94(saturation_vapor_pressure, surface_vapor_density)

Computes precipitable water [cm] as proposed in [15, Eq. 1].

The accuracy of this method is approximately 20% for moderate precipitable water (1-3 cm) and less accurate otherwise.

pressure2altitude(pressure)

Computes the local altitude from site pressure.

The following assumptions [19] hold:

• Base pressure: 101325 Pa
• Temperature at zero altitude: 288.15 K
• Gravitational acceleration: 9.80665 m/s^2
• Lapse rate: -6.5E-3 K/m
• Gas constant for air: 287.053 J/(kg K)
• Relative Humidity: 0%

relative_airmass_gueymard1993(solpos::SolarPosition)

Computes the relative airmass as proposed in [12, 20].

relative_airmass_gueymard2003(solpos::SolarPosition)

Computes the relative airmass as proposed in [21, 22].

relative_airmass_kasten1966(solpos::SolarPosition)

Computes the relative airmass as proposed in [23].

relative_airmass_kastenyoung1989(solpos::SolarPosition)

Computes the relative airmass as proposed in [24].

relative_airmass_pickering2002(solpos::SolarPosition)

Computes the relative airmass as proposed in [25].

relative_airmass_simple(solpos::SolarPosition)

Computes the relative airmass as secant of the Sun's apparent zenith.

relative_airmass_young1994(solpos::SolarPosition)

Computes the relative airmass as proposed in [26].

relative_airmass_youngirvine1967(solpos::SolarPosition)

Computes the relative airmass as proposed in [27].

relative_humidity_oke2018(vapor_pressure, saturation_vapor_pressure)

Computes the relative humidity [%] as proposed in [28].

saturation_vapor_pressure_gueymard93(air_temperature)

Computes the saturation water vapor pressure [mbar] as proposed in [12, Eq. 1].

saturation_vapor_pressure_oke2018(dew_temperature)

Computes the saturation water vapor pressure [mbar] as proposed in [28].

surface_vapor_density_gueymard94(
    air_temperature,
    relative_humidity,
    apparent_vapor_scale_height
)

Computes the surface water vapor density [g/m³] as proposed in [15, Eq. 2].

vapor_pressure_oke2018(air_temperature)

Computes the water vapor pressure [mbar] as proposed in [28].