UV radiation monitoring: UV index and UV dose

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UV radiation
monitoring:

UV index
UV dose

Main data product pages: Erythemal UV index  |  Daily erythemal UV dose

 

 
Introduction to
UV radiation
monitoring

UV radiation
UV & health
UV index
forecasts of
UV index
UV dose
example:
1 June 2002
links

 

Example of UV index and UV dose based on GOME
-- 1 June 2002

Some additional things regarding the example of UV index and UV dose derivation:
 

 


 

Cloud cover examples

 
Meteosat cloud cover fraction at 12h GMT Example of the Meteosat cloud cover fraction at 12 GMT on 1 June 2002, re-gridded to a 0.5x0.5 degree grid for the UV dose. The cloud cover information is available only for the the area used in HIRLAM.

To compute the UV dose of a particular day in this domain, 1-hourly cloud cover information is necessary between 20h GMT of the day before and 02h GMT of the next day.

Animated gif (1.1 MB) for 1 June 2002.

NOAA-16 image af 12:17 UTC NOAA-16 image af 13:57 UTC
NOAA-16 images (visible, 0.58-0.68 µm) of 12.17 UTC (right) and 13.57 UTC (left)
on 1 June 2002 --- © NERC Satellite Receiving Station, Dundee.
 

 


 

Values at a certain location

The erythemal UV index and erythemal UV dose are computed at a grid of 0.5 by 0.5 degrees,
which is about 50 by 50 kilometers at the equator.
The value at a certain longitude-latitude coordinate is the value of the grid cell within which
this given coordinate falls.
Rome, for example, is at {12.23,41.80} and the centre of the grid cell is {12.25,41.75}.

Extracting the values at a certain location for a whole year gives a time series.
For example for Rome:

Time series for Rome Time series for Rome of the erythemal daily UV dose (red), clear-sky UV dose (green) and clear-sky UV index (blue).
For the UV index, 1 unit equals 25 mW/m2; the UV dose is given in kJ/m2.

The gap in the curve of the UV index at 13 and 14 Feb. is due to missing ozone data, which means that the UV dose cannot be computed either.

The curve of the erythemal UV dose contains 20 more gaps, for example around 15 June. These gaps are due to missing cloud cover information.

Time series for Rome Time series for Rome of the erythemal daily UV dose for different cloud circumstances, given in kJ/m2.

The clear-sky erythemal UV dose (green) is the maximum UV dose that would have occurred if all days of the year had been cloud-free.

The overcast erythemal UV dose (blue) is the minimum UV dose that would have occurred if all days of the year had been fully clouded.

The actual erythemal UV dose (red dots; same as the red line in the above figure) falls between the clear-sky and the overcast UV dose.

 


 

Animations of UV dose for a month

 
Erythemal UV dose The erythemal UV dose on 1 May 2002 for Europe, on the basis of Meteosat cloud cover data.

Animated gif (1.5 MB) for May 2002; the image of 12 May is missing due to missing cloud data.

Erythemal UV dose The erythemal UV dose on 1 August 2002 for Europe, on the basis of Meteosat cloud cover data. At the top-left corner there is data missing due to missing cloud data.

Animated gif (1.5 MB) for August 2002.

 


last modified: 24 July 2017
data product contact: Jos van Geffen & Ronald van der A
Copyright © KNMI / TEMIS