RESULTS - CMF CLIMATOLOGY

COST 726 UV CLOUD MODIFICATION FACTOR CLIMATOLOGY over Europe
( 25E to 35W and 30N to 80N )
from 1958 to 2004
 

Description
Calculation of the UV-Cloud modification factor (CMF) bases on a transformation of the SOL-CMF following the algorithmus of den Outer et al. (2005).
This algorithm is also the basis for the calculation of the COST UV-Index Climatology.
Transformation SOL-CMF --> CMFUV:
CMFUV=(1-exp(-0.23*ln(1+Pfac*SOL-CMF)))/(1-exp(-0.23*ln(1+Pfac)))
where
Cos(SZAmin) | Pfac
-----------------------------
0.00 - 0.15 | 6.12888
0.15 - 0.30 | 4.40254
0.30 - 0.45 | 3.03030
0.45 - 0.60 | 1.93951
0.60 - 0.75 | 1.07246
0.75 - 1.00 | 0.38325
where
SZAmin = Minimal Solar Zentih Angle for day.

The plot below shows the relation between CMF(global solar) and CMF(UV erythema) depending on solar zenith angle.

Relation: CMF (solar) versus CMF(UV erythema)

At the end of this page you can find download of this climatology.

Monthly averages
Below you can find graphics (left side) of averaged erythemal UV Cloud Modification Factor for each month of the year.
Monthly averages are calculated from the years 1958 to 2002 from daily values.
On the right side the corresponding accuracy is shown. The accuracy of monthly averages depends on the density of stations.
Calculations and graphics were provided by: H. Staiger.

JANUARYFEBRUARY
Average Accuracy Average Accuracy
March APRIL
Average Accuracy Average Accuracy
MAY JUNE
Average Accuracy Average Accuracy
JULY AUGUST
Average Accuracy Average Accuracy
SEPTEMBER OCTOBER
Average Accuracy Average Accuracy
NOVEMBER DECEMBER
Average Accuracy Average Accuracy

Download and data information

Data format:
The files (*.txt) contain yearly gridded (1x1 degrees in latitude and longitude) daily (or monthly) Cloud Modification Factors for UV (CMFUV) calculated based on the solar cloud modification factors from Henning Staiger.
The file format is exactly the same as the original files:
similar to the format of total ozone files i.e. the grid dimensions are 61x50 covering longitudes 25W-35E and latitudes 80N-31N in a regular lat-lon grid with 1 degree spacing. See the total ozone readme file for details. Column delimiter is one blank space, record delimiter is carriage return + line feed.

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 monthly averages (*.zip):
1958-2004 (2.6 MB)

Download monthly accuracy (*.zip):
1958-2004 (2.0 MB)

Download daily data by period (*.zip):
1958-1970(21.5)MB 1971-1980(16.5 MB) 1981-1993(21.5 MB) 1994-2002(14 MB) 2002-2004 (3 MB)

Download daily data by year (*.txt, 7.9 MB each year)
---- ---- ---- ---- ---- ---- ---- ---- 1958 1959
1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
1970 1971 1972 1973 1974 1975 1976 1977 1978 1979
1980 1981 1982 1983 1984 1985 1986 1987 1988 1989
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999
2000 2001 2002 2003 2004 ---- ---- ---- ---- ----

References:
Den Outer, P. N., Slaper, H., and Tax, R. B. (2005)
UV radiation in the Netherlands. Assessing long-term variability and trends in relation to ozone and clouds,
J. Geophys. Res., 110, D02203, 1-11, doi: 10.1029/2004JD004824.


Last Update: March 2009,
by A.W.Schmalwieser