UV dose: availability cloud modification data

UV dose: availability of cloud modification data	UV archive overview
Daily UV dose: erythemal \| vitamin-D \| DNA-damage Time series of UV data

Cloud-modified UV dose data
The UV dose is the effective UV irradiance (given in kJ/m2) reaching the Earth's surface integrated over the day and taking the attenuation of the UV radiation due to clouds into account. For comparison sake the UV dose assuming cloud-free conditions is also given.
The cloud data is compiled from observations by geostationary satellites:

Meteosat Second Generation (MSG) satellites -- available in principle once every 15 minutes since 19 January 2004 and used up to 31 December 2025
Meteosat Third Generation (MTG) satellites -- available in principle once every 10 minutes and in use as of 01 January 2026
provided by the MSG Cloud Physical Properties (CPP) project.
Because we compute the daily UV dose, we need cloud data over the full day. Once and a while one or more time steps of MSG/MTG data are missing or are incomplete. Though we can fill in missing quarters on the basis of persistence (i.e. using the data from the preceeding quarter), we do not want to have data gaps that are 1 hour (4 quarters) or longer.

See this page for more details on the cloud modification applied.

For days with large data gaps in the MSG/MTG data or no MSG/MTG data at all we can therefore not compute the cloud-modified UV dose. The following graph and table show when this has occurred -- these overviews are updated manually on an irregualar basis. In addition to this, there are some days when a section of the MSG/MTG data is missing, and thus a sectionof the UV dose data is missing.

*** MSG data: 2004 -- 2025 | MTG data: 2026 -- present ***

year total missing days (MM/DD)

2026 -- [ last updated: 12 January ]

2025 03/08, 11/11, 11/16

2024 2 08/17, 11/01

2023 4 01/20, 02/09, 03/21, 12/06

2022 8 01/18, 01/19, 01/20, 01/21, 01/22, 07/25, 11/11
12/21

2021 5 05/22, 09/30, 10/08, 12/19, 12/20

2020 0 --

2019 2 03/12, 07/02

2018 3 05/06, 07/11, 12/11

2017 3 09/22, 11/07, 12/10

2016 3 05/11, 06/10, 10/15

2015 3 04/28, 11/15, 12/24

2014 2 03/26, 07/28

2013 3 02/06, 08/18, 09/21

2012 3 01/19, 08/31, 12/07

2011 26 01/05, 02/02, 02/05, 02/06, 02/21, 02/22, 02/24,
02/28, 03/09, 03/16, 03/19, 03/20, 03/21, 03/28,
04/01, 04/10, 04/12, 04/19, 05/13, 05/14, 05/15,
05/16, 05/19, 08/11, 09/04, 09/05

2010 7 03/18, 04/20, 07/14, 08/19, 09/11, 11/24, 12/24

2009 10 01/04, 02/04, 04/17, 05/16, 07/08, 08/05, 08/15,
08/21, 11/05, 11/09

2008 14 05/13, 05/20, 07/21, 09/24, 10/14, 10/15, 11/25,
11/29, 11/30, 12/01, 12/02, 12/09, 12/10, 12/22

2007 4 06/05, 06/25, 08/17, 08/31

2006 9 01/09, 01/10, 01/11, 01/12, 01/21, 05/18, 09/23,
09/24, 09/25

2005 11 01/10, 01/11, 01/12, 01/13, 03/12, 03/15, 03/18,
04/18, 04/20, 05/29, 06/20

2004 17 01/19, 01/20, 01/21, 03/28, 04/08, 06/23, 06/30,
08/12, 09/29, 10/04, 10/05, 10/06, 10/07, 10/12,
10/13, 11/16, 12/09
[ first MSG data recorded on 19 Jan. ]

year	total	missing days (MM/DD)
2026		-- [ last updated: 12 January ]
2025		03/08, 11/11, 11/16
2024	2	08/17, 11/01
2023	4	01/20, 02/09, 03/21, 12/06
2022	8	01/18, 01/19, 01/20, 01/21, 01/22, 07/25, 11/11 12/21
2021	5	05/22, 09/30, 10/08, 12/19, 12/20
2020	0	--
2019	2	03/12, 07/02
2018	3	05/06, 07/11, 12/11
2017	3	09/22, 11/07, 12/10
2016	3	05/11, 06/10, 10/15
2015	3	04/28, 11/15, 12/24
2014	2	03/26, 07/28
2013	3	02/06, 08/18, 09/21
2012	3	01/19, 08/31, 12/07
2011	26	01/05, 02/02, 02/05, 02/06, 02/21, 02/22, 02/24, 02/28, 03/09, 03/16, 03/19, 03/20, 03/21, 03/28, 04/01, 04/10, 04/12, 04/19, 05/13, 05/14, 05/15, 05/16, 05/19, 08/11, 09/04, 09/05
2010	7	03/18, 04/20, 07/14, 08/19, 09/11, 11/24, 12/24
2009	10	01/04, 02/04, 04/17, 05/16, 07/08, 08/05, 08/15, 08/21, 11/05, 11/09
2008	14	05/13, 05/20, 07/21, 09/24, 10/14, 10/15, 11/25, 11/29, 11/30, 12/01, 12/02, 12/09, 12/10, 12/22
2007	4	06/05, 06/25, 08/17, 08/31
2006	9	01/09, 01/10, 01/11, 01/12, 01/21, 05/18, 09/23, 09/24, 09/25
2005	11	01/10, 01/11, 01/12, 01/13, 03/12, 03/15, 03/18, 04/18, 04/20, 05/29, 06/20
2004	17	01/19, 01/20, 01/21, 03/28, 04/08, 06/23, 06/30, 08/12, 09/29, 10/04, 10/05, 10/06, 10/07, 10/12, 10/13, 11/16, 12/09 [ first MSG data recorded on 19 Jan. ]

UV dose: availability of cloud modification data

Cloud-modified UV dose data