Daily cloud-modified erythemal UV index for The Netherlands

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Clear-sky UV index:   erythemal == regular archive maps & data
 

 
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Date range:
01 Jan 2024
-- 14 Mar 2025

Archive days
without cloud data
:
17 Aug. 2024
01 Nov. 2024


 
For measurements of
today's UV index at
RIVM (Bilthoven), see
this page (= in Dutch)

 

Introduction

The plots on this page show for selected places in The Netherlands the UV index throughout the day, both cloud-free (thin blue line) and cloud-modified (red line/points) -- if the latter is absent, then cloud cover data is not available.

Today's cloud-modified UV index (available as of about 04:30 UTC) is updated when new cloud cover data arrives, which usually is every 15 minutes -- you may have to use shift-reload to see the latest images.

Data from 2024 has been reprocessed to provide some comparison.


[ basemap: Wikimedia ]  

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Erythemal UV index of 15 February 2025

(click on image to enlarge)
UV index for Den Burg UV index for Schiermonnikoog of 15 February 2025
UV index for De Bilt
UV index for Vlissingen UV index for Vaals of 15 February 2025
 
download the data :  regular 0.25° netCDF file  |  high-res 0.05° netCDF file


Some info on the data file

The data file contains the cloud-free and cloud-modified UV index for an area covering The Netherlands for each quarter of an hour from 03:00 UTC up to and including 21:45 UTC, both in the usual non-dimentional unit, and given with 3 decimals. For quarters with insufficient sunlight to determine the UV index or the cloud data or with missing cloud data, the entries have fill-values (-1.0).

The original resolution of the data is the same as the standard UV grid: 0.25 by 0.25°. The line plots shown above are extracted from these data.

A version at higher resolution is made by interpolating the cloud-free data to 0.05 by 0.05° and then averaging the cloud data over 0.15 by 0.15° around the grid cell center. This "hr" version is available as of 11 February 2025 (back-processing of the archive is not feasible).

The example maps on the right show the area that is covered by the data: longitude = 3.00 – 7.75°E, latitude = 50.25 – 54.00°N, at:
(top) the original resolution, i.e. divided in 19 by 15 grid cells of 0.25 by 0.25°, and
(bottom) the higher resolution, i.e. divided in 95 by 75 grid cells of 0.05 by 0.05°

Most important global attributes:
  • data_product_date = date of the data in the file
  • date_created = date the data file was created
  • latest_cloud_modified_time = UTC time of the last time slice filled with cloud-modified UV index data
  • data_product_status = "near-real time" for the operational processing (as of 5 Dec. 2024) or "archive" for reprocessing data
 
Main data variables:
  • uvi_clear = Erythemal UV index cloud-free
  • uvi_cloudy = Erythemal UV index cloud-modified
  • status = Status of cloud-modified data:
      0 = not available
      1 = available for at least one grid cell
      2 = forecast cloud data used (reserved flag)
plus grid cell coordinate & time data.
Data file(s) can be downloaded from the links provide above under the graph with the date in the filename. Today's data is also available with a static filename via:
* https://www.temis.nl/uvradiation/UVI/uviec_nl.nc
== 0.25 degree
* https://www.temis.nl/uvradiation/UVI/uviec_nl_hr.nc
== 0.05 degree
 
 
Cloud-free UV index The Netherlands 21 June 2024 at 12:00 UTC
 
Cloud-modified UV index The Netherlands 21 June 2024 at 12:00 UTC
 
Example plots of the cloud-free and cloud-modified UV index at 12:00 UTC for 21 June 2024 at a resoltion of 0.25 by 0.25° (above) and 0.05 by 0.05° (below)
 
Cloud-free UV index The Netherlands 21 June 2024 at 12:00 UTC
 
Cloud-modified UV index The Netherlands 21 June 2024 at 12:00 UTC

 

 


last modified: 13 February 2025
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