[CF-metadata] albedo, air pressure definitions [SEC=UNCLASSIFIED]

From: Ian Grant <I.Grant>
Date: Mon, 27 Jul 2015 06:27:35 +0000

Hi Nan,

Regarding your proposed definition of albedo: 'Albedo is the ratio of reflected radiation from the surface to incident radiation upon it'. This is essentially correct.

However, you and others might want to consider a more thorough definition:
'Albedo is the ratio of the radiant flux exiting a reference surface into the whole hemisphere to the radiant flux incident on the same surface from the hemisphere.'
To make it even clearer and more complete, this could be added:
'The albedo, also called the bihemispherical reflectance, is often the ratio of upwelling flux to downwelling flux at a horizontal surface, such as the reflected and incident radiation at an interface.'

My definition is adapted from Schaepman-Strub et al. (2006, ' Reflectance Quantities in Optical Remote Sensing: Definitions and Case Studies', Remote Sensing of Environment, 103, 27-42, doi:10.1016/j.rse.2006.03.002).

The need to specify the reference level is discussed in the introduction to Pinty et al. (2005, 'Coupling Diffuse Sky Radiation and Surface Albedo', Journal of the Atmospheric Sciences, 62 (7), 2580-2591).

Regards,
Ian


Ian Grant | Satellite Specialist

Observations & Infrastructure Division | Science & Engineering Section
Bureau of Meteorology
GPO Box 1289 Melbourne VIC 3001
Level 5, 700 Collins Street, Docklands VIC 3008
Tel: +61 3 9669 4080 | i.grant at bom.gov.au
www.bom.gov.au
Received on Mon Jul 27 2015 - 00:27:35 BST