Description of the Daily UV surface albedo
(by H. Staiger, 30. April 2008)

Summary
Daily values of UV surface albedo at 360 nm are provided for the period 01 Jan 1958 to 31 Aug 2002 and for each pixel of the COST-726 area. The available ERA-40 fields of water equivalent of snow depth in mm and of sea-ice fraction enable grid boxes to be identified, which are covered by snow, and / or (partly) by sea-ice. Furthermore, the snow age can be derived by the evolution of snow depth in the past days, and the snow depth in cm can be estimated using snow age dependent assumptions on the relation of water equivalent in mm and snow depth in cm. The albedo of snow and ice free pixels is set at the corresponding value of the daily FMI MTW UV surface albedo climatology. For parts of the COST-726 area monthly means of albedo for freshly fallen and for old snow can be derived from the MTW UV surface climatology and can be used in determining the current albedo. In case of snow at first the algorithm of Schwander is applied to calculate a regional albedo, which depends on snow depth and snow age and can vary between 19 and 50 %. In regions, monthly albedo means for freshly fallen snow and old snow are not defined, the albedo of the pixel is set at the regional albedo. In case the monthly albedo means are defined, the regional albedo related to its maximal possible difference is applied to scale between the albedo of freshly fallen and of old snow.

Usage
Non-commercial: This climatology is free for non-comercial use. In any application aknowledgement has to be given to the Action COST726 (www.cost726.org) and to H. Staiger. In case of publication additional reference 1 (see below) has to be citated.
In any other case: you have to contact the developer: H. Staiger

Download complete description:
Description (pdf, 0.3 MB)

Download climatology:
UV Albedo Climatology (zip, 20.4 MB)

Reference 1:
 COST ACTION 726 - Long term changes and climatology of UV radiation over Europe
Final Report
COST Office in press