NWP Parameters

General

We are consuming two different forecast models from the Met Office: UKV and MOGREPS. UKV is the 'deterministic' forecast. MOGREPs is the ensemble forecast.

> More about MOGREPS

Irradiance Parameters

There are three irradiance parameters that we're capturing from SNS:

1. surface_diffusive_downwelling_shortwave_flux_in_air
2. surface_direct_downwelling_shortwave_flux_in_air
3. surface_downwelling_shortwave_flux_in_air

Jack says:

The third is I think the most important (I think the param 3 = param 1 + param 2)

UKV

SNS Param Name	Description	Full Description	Units	Time Steps (Summary)	Time Interpretation
surface_diffusive_downwelling_shortwave_flux_in_air	radiation flux in shortwave diffuse downward at surface	Shortwave radiation at the surface from above directed at the ground. “Diffuse” means that the radiation has been scattered by particles in the atmosphere such as cloud droplets and aerosols. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics.	W m-2	Hourly (0-54) 3-hourly (51-120)	Instantaneous
surface_direct_downwelling_shortwave_flux_in_air	radiation flux in shortwave direct downward at surface	Shortwave radiation at the surface from above directed at the ground. ”Direct” means that the radiation has followed a direct path from the sun and is alternatively known as “direct insolation”. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics.	W m-2	Hourly (0-54) 3-hourly (51-120)	Instantaneous
	radiation flux in shortwave net at surface	Shortwave radiation at the surface from above directed at the ground. Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics.	W m-2	Hourly (0-54) 3-hourly (51-120)	Instantaneous
surface_downwelling_shortwave_flux_in_air	radiation flux in shortwave total downward at surface	Shortwave radiation at the surface from above directed at the ground. “Total” means the sum of direct and diffuse solar radiation incident on the surface and is sometimes called “global radiation”. Shortwave radiation at the surface from above directed at the ground.	W m-2	Hourly (0-54) 3-hourly (51-120)	Instantaneous

(Excerpt is taken from Met Office UKV documentation)

MOGREPS

SNS Param Name	Description	Full Description	Units	Time Steps (Summary)	Time Interpretation
	radiation flux in longwave downward at surface	Longwave radiation at the surface from above directed at the ground. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics.	W m-2	Hourly (1-125)	Instantaneous
surface_diffusive_downwelling_shortwave_flux_in_air	radiation flux in shortwave diffuse downward at surface	Shortwave radiation at the surface from above directed at the ground. “Diffuse” means that the radiation has been scattered by particles in the atmosphere such as cloud droplets and aerosols. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics.	W m-2	Hourly (1-126)	Instantaneous
surface_direct_downwelling_shortwave_flux_in_air	radiation flux in shortwave direct downward at surface	Shortwave radiation at the surface from above directed at the ground. “Direct” means that the radiation has followed a direct path from the sun and is alternatively known as “direct insolation”. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics.	W m-2	Hourly (1-126)	Instantaneous
surface_downwelling_shortwave_flux_in_air	radiation flux in shortwave total downward at surface	Shortwave radiation at the surface from above directed at the ground. “Total” means the sum of direct and diffuse solar radiation incident on the surface and is sometimes called “global radiation”. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics.	W m-2	Hourly (1-125)	Instantaneous

(Excerpt is taken from Met Office MOGREPS documentation)