UV index and UV dose: netCDF data file structure data version 2.x	UV radiation monitoring: UV index UV dose
Main data product description page

netCDF data file structure

This page describes the format of yearly netCDF files with daily data.
The daily HDF-4 files with daily data are described here.

The daily data of UV index and UV dose fields is stored in four yearly netCDF data files.
Similar files are used for climatologies, i.e. long-term term averages over the data.
These files can be downloaded directly from:
  * this page for operational UV data, and
  * this page for MSR-2 based UV data.

Simply said, such files have the following structure:

• A set of global attributes
  these specify the product name, data, version, etc.
• A group ALGORITHM_SETTINGS with a set of group attributes
  these list a number of settings used in the TEMIS UV algorithm
• A group PRODUCT that contains the data variables:
  • Latitude and longitude of grid cell centres and grid cell corners
  • Information on the date of the data stored
  • The data sets of the file, depending on which file is selected:
    • Erythemal UV index & ozone column data
    • Erythemal or Vitamin-D or DNA-damage UV dose cloud-free & cloud-modified
    where the UV index and UV dose are accompanied by an error estimate.

Files in the netCDF format, an expanded version of HDF-5, can be read by a multitude of modern programs, including Python, R, Fortran, C, IDL. The UV index and UV dose files can be viewed with the Panoply netCDF, HDF and GRIB Data Viewer.

 
Yearly UV index & UV dose netCDF data file structure

The following table gives as an overview of the yearly netCDF file structure for daily UV index & UV dose data in four sections:

1. The global attributes of the netCDF file
2. The ALGORITHM_SETTINGS group attributes
3. The data sets with daily data and their attributes
4. The data sets with climatological data and their attributes

Per entry multiple lines are used to list the different possibilities, where:
  * Entries with white background are UV index & ozone data entries
  * Entries with blue background are UV dose data entries
  * Entries with page colour background are common entries

For the data files from the MSR-2 record:
  * Entries that differ from those of the operational data are in italic
  * There is no cloud-modified data
  * There is no climatological data

Note that each netCDF files comes in two versions: one with data covering the whole world and one with data covering only (a large part of) Europe; see the global attributes "data_geo_coverage" and "id".

 
 

Global attribute	Value    * YYYY = product year of daily data    * Differences between daily data and climatological data is shown by sub-columns    * Differences in geographic coverage are separated by ||    * Entries different for the MSR-2 data are in italic
title	TEMIS UV index and UV dose operational data products
	TEMIS UV index and UV dose Multi-Sensor Re-analysis data products
institution	KNMI / ESA
project	TEMIS UV
authors	M. van Weele & J. van Geffen
affiliation	KNMI (Royal Netherlands Meteorological Institute)
email	weelevm@knmi.nl & geffen@knmi.nl
doi	10.21944/temis-uv-oper-v2
	10.21944/temis-uv-msr2-v2
reference	http://www.temis.nl/uvradiation/
data_description	Daily data	Daily climatology
data_geo_coverage	World  ||  Europe
data_period  [1]	YYYY	2004-2020
data_period_minimum_count  [1]	--	12
data_version  [2]	2.0
naming_authority	nl.knmi
data_product	Erythemal UV index & ozone column
data_product	Erythemal UV dose cloud-free & cloud-modified Vitamin-D UV dose cloud-free & cloud-modified DNA-damage UV dose cloud-free & cloud-modified
	Erythemal UV dose cloud-free Vitamin-D UV dose cloud-free DNA-damage UV dose cloud-free
data_product_code  [3]	tiefdv	tiefdc
	miefdv	--
data_product_code  [3]	tdecdv tdvcdv tddcdv	tdecdc tdvcdc tddcdc
	mdecdv mdvcdv mddcdv	--
id  [4]	uviefYYYY_world || uviefYYYY_europe	uviefclim_world || uviefclim_europe
	uviefYYYY_msr_world || uviefYYYY_msr_europe	--
id  [4]	uvdecYYYY_world || uvdecYYYY_europe uvdvcYYYY_world || uvdvcYYYY_europe uvddcYYYY_world || uvddcYYYY_europe	uvdecclim_world || uvdecclim_europe uvdvcclim_world || uvdvcclim_europe uvddcclim_world || uvddcclim_europe
	uvdecYYYY_world || uvdecYYYY_europe uvdvcYYYY_world || uvdvcYYYY_europe uvddcYYYY_world || uvddcYYYY_europe	--
geospatial_lat_max	90. || 70.
geospatial_lat_min	-90. || 30.
geospatial_lon_max	180. || 45.
geospatial_lon_min	-180. || -25.
geospatial_lat_resolution	0.25 degree
geospatial_lon_resolution	0.25 degree
geospatial_lat_units	degrees_north
geospatial_lon_units	degrees_east
The climatology is an average over the data_period with a data_period_minimum_count set to the required number of available data points (i.e. years) for each day. The data_version for all netCDF files is currently 2.0, even though at some point the data processing was updated; see this list for a version overview. See this page for info on the meaning of the product code. The 'id' is the filename withouth the file extension.
Algorithm attribute	Value
Aerosol_AOD_368nm	0.3
Aerosol_ssa	0.9
Cloud_modification	Derived from MSG CPP surface downwelling solar radiation (SDS) data
	Cloud-free datasets only
Data_created_by  [1]	TM3-DAM, version 4.3 & temisuv, version 2.0
Earth-Sun_factor	( D / D_0 )^2 with D/D_0 computed with Kepler's first from the        perihelion and eccentricity of the Earths orbit for each day
Ozone_data	Assimilated global ozone field at local solar noon
Ozone_data_source	TEMIS operational ozone processing, started 01 July 2002
	Multi-Sensor Re-analysis (MSR) ozone record, version 2
Surface_albedo	GOME-2A based 0.25x0.25 degree surface albedo at 340nm,        interpolated to the data day
Surface_albedo_version  [2]	Product algorithm version 2.1
Surface_albedo_data	http://www.temis.nl/uvradiation/product/albedo.php
Surface_albedo_correction	( 1.0-0.25*0.09 ) / ( 1.0-0.25*albedo )       w.r.t. De Bilt=0.09
Surface_elevation	GMTED2010 elevation data regridded at 0.250 degree resolution
Surface_elevation_correction	( 1.0+0.5*elevation )       with elevation given in km
Surface_elevation_data	http://temis.nl/data/gmted2010/
See note above on the 'temisuv' data_version for all netCDF files; the TM3-DAM version may be slightly different. As of data_version 2.1 the Surface_albedo_version is actually 3.1; this algorithm attribute has not been updated accordingly.
Daily data
Data set  --  data type       Attribute	Rank --> dimensions       Value            * Size of dimensions is only mentioned at first occurrence            * Differences in geographic coverage are separated by ||
latitude  --  float  ==  dimension       long_name       units       bounds       axis       _FillValue	1 --> latitude  ==  720  ||  160       grid cell centre latitude       degrees_north       latitude_bounds       Y       9.96921e+36f
longitude  --  float  ==  dimension       long_name       units       bounds       axis       _FillValue	1 --> longitude  ==  1440  ||  280       grid cell centre longitude       degrees_east       longitude_bounds       X       9.96921e+36f
corner  --  ubyte  ==  dimension       long_name       comment       units       _FillValue	1 --> corner  ==  4       grid cell corner index       The indices for the grid cell corners (counter-clockwise).       1       255UB
year  --  int  ==  dimension       long_name       comment       units       _FillValue	1 --> year  ==  1       year       The current year.       1       -1
days  --  int  ==  dimension       long_name       comment       units       _FillValue	1 --> days  ==  365  or  366       day number       The day in the current year.       1       -1
latitude_index  --  int       long_name       comment                   units       axis       _FillValue	1 --> latitude       grid cell centre latitude index (0-based)       latitude_index = round ( latitude + 90.0 - dlat/2.0 ) / dlat ,             with dlat = 0.25 degrees.       1       Y       -1
longitude_index  --  int       long_name       comment                   units       axis       _FillValue	1 --> longitude       grid cell centre longitude index (0-based)       longitude_index = round ( longitude + 180.0 - dlon/2.0 ) / dlon ,             with dlon = 0.25 degrees.       1       X       -1
latitude_bounds  --  float       long_name       units       _FillValue	2 --> latitude, corner       grid cell corner latitude       degrees_north       9.96921e+36f
longitude_bounds  --  float       long_name       units       _FillValue	2 --> longitude, corner       grid cell corner longitude       degrees_east       9.96921e+36f
date  --  int       long_name       comment       units       _FillValue	1 --> days       date of the day number       Format is YYYYMMDD, stored as integer.       1       -1
date_string  --  string       long_name       comment       units       _FillValue	1 --> days       date of the day number       Format is YYYYMMDD, stored as string.       1       ""
date_month  --  int       long_name       comment       units       _FillValue	1 --> days       month number for each day       ""       1       -1
uvi_clear  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV index (cloud-free) at local solar noon       1       -1.0       latitude longitude       -1.0
uvi_clear_error  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV index (cloud-free) at local solar noon error estimate       1       -1.0       latitude longitude       -1.0
ozone_column  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Ozone column at local solar noon       DU       -1.0       latitude longitude       -1.0
uvd_clear  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-free       Vitamin-D UV dose cloud-free       DNA-damage UV dose cloud-free       kJ/m2       -1.0       latitude longitude       -1.0
uvd_clear_error  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-free error estimate       Vitamin-D UV dose cloud-free error estimate       DNA-damage UV dose cloud-free error estimate       kJ/m2       -1.0       latitude longitude       -1.0
uvd_cloudy  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-modified       Vitamin-D UV dose cloud-modified       DNA-damage UV dose cloud-modified       kJ/m2       -1.0       latitude longitude       -1.0
uvd_cloudy_error  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-modified error estimate       Vitamin-D UV dose cloud-modified error estimate       DNA-damage UV dose cloud-modified error estimate       kJ/m2       -1.0       latitude longitude       -1.0
cloud_mod_factor  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       average cloud modification factor       1       -1.0       latitude longitude       -1.0
earth_sun_factor  --  float       long_name       units       _FillValue	3 --> days, latitude, longitude       sun-earth distance correction factor       1       -1.0
Climatological data
Data set  --  data type       Attribute	Rank --> dimensions       Value
latitude  --  float  ==  dimension       long_name       units       bounds       axis       _FillValue	1 --> latitude  ==  720  ||  160       grid cell centre latitude       degrees_north       latitude_bounds       Y       9.96921e+36f
longitude  --  float  ==  dimension       long_name       units       bounds       axis       _FillValue	1 --> longitude  ==  1440  ||  280       grid cell centre longitude       degrees_east       longitude_bounds       X       9.96921e+36f
corner  --  ubyte  ==  dimension       long_name       comment       units       _FillValue	1 --> corner  ==  4       grid cell corner index       The indices for the grid cell corners (counter-clockwise).       1       255UB
days  --  int  ==  dimension       long_name       comment       units       _FillValue	1 --> days  ==  365       day number       The day in the year; leapday 29 Feb. is skipped.       1       -1
latitude_index  --  int       long_name       comment                   units       axis       _FillValue	1 --> latitude       grid cell centre latitude index (0-based)       latitude_index = round ( latitude + 90.0 - dlat/2.0 ) / dlat ,             with dlat = 0.25 degrees.       1       Y       -1
longitude_index  --  int       long_name       comment                   units       axis       _FillValue	1 --> longitude       grid cell centre longitude index (0-based)       longitude_index = round ( longitude + 180.0 - dlon/2.0 ) / dlon ,             with dlon = 0.25 degrees.       1       X       -1
latitude_bounds  --  float       long_name       units       _FillValue	2 --> latitude, corner       grid cell corner latitude       degrees_north       9.96921e+36f
longitude_bounds  --  float       long_name       units       _FillValue	2 --> longitude, corner       grid cell corner longitude       degrees_east       9.96921e+36f
date  --  int       long_name       comment       units       _FillValue	1 --> days       month and day of the day number       Format is MMDD, stored as integer.       1       -1
date_string  --  string       long_name       comment       units       _FillValue	1 --> days       month and day of the day number       Format is MMDD, stored as string.       1       ""
date_month  --  int       long_name       comment       units       _FillValue	1 --> days       month number for each day       ""       1       -1
uvi_clear_mean  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV index (cloud-free) at local solar noon average       1       -1.0       latitude longitude       -1.0
uvi_clear_stddev  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV index (cloud-free) at local solar noon standard deviation       1       -1.0       latitude longitude       -1.0
uvi_clear_min  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV index (cloud-free) at local solar noon minimum       1       -1.0       latitude longitude       -1.0
uvi_clear_max  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV index (cloud-free) at local solar noon maximum       1       -1.0       latitude longitude       -1.0
ozone_column_mean  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Ozone column at local solar noon average       DU       -1.0       latitude longitude       -1.0
ozone_column_stddev  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Ozone column at local solar noon standard deviation       DU       -1.0       latitude longitude       -1.0
ozone_column_min  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Ozone column at local solar noon minimum       DU       -1.0       latitude longitude       -1.0
ozone_column_max  --  int       long_name       units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Ozone column at local solar noon maximum       DU       -1.0       latitude longitude       -1.0
uvd_clear_mean  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-free at local solar noon average       Vitamin-D UV dose cloud-free at local solar noon average       DNA-damage UV dose cloud-free at local solar noon average       kJ/m2       -1.0       latitude longitude       -1.0
uvd_clear_stddev  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-free at local solar noon standard deviation       Vitamin-D UV dose cloud-free at local solar noon standard deviation       DNA-damage UV dose cloud-free at local solar noon standard deviation       kJ/m2       -1.0       latitude longitude       -1.0
uvd_clear_min  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-free at local solar noon minimum       Vitamin-D UV dose cloud-free at local solar noon minimum       DNA-damage UV dose cloud-free at local solar noon minimum       kJ/m2       -1.0       latitude longitude       -1.0
uvd_clear_max  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-free at local solar noon maximum       Vitamin-D UV dose cloud-free at local solar noon maximum       DNA-damage UV dose cloud-free at local solar noon maximum       kJ/m2       -1.0       latitude longitude       -1.0
uvd_cloudy_mean  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-modified at local solar noon average       Vitamin-D UV dose cloud-modified at local solar noon average       DNA-damage UV dose cloud-modified at local solar noon average       kJ/m2       -1.0       latitude longitude       -1.0
uvd_cloudy_stddev  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-modified at local solar noon standard deviation       Vitamin-D UV dose cloud-modified at local solar noon standard deviation       DNA-damage UV dose cloud-modified at local solar noon standard deviation       kJ/m2       -1.0       latitude longitude       -1.0
uvd_cloudy_min  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-modified at local solar noon minimum       Vitamin-D UV dose cloud-modified at local solar noon minimum       DNA-damage UV dose cloud-modified at local solar noon minimum       kJ/m2       -1.0       latitude longitude       -1.0
uvd_cloudy_max  --  int       long_name                   units       no_data_value       coordinates       _FillValue	3 --> days, latitude, longitude       Erythemal UV dose cloud-modified at local solar noon maximum       Vitamin-D UV dose cloud-modified at local solar noon maximum       DNA-damage UV dose cloud-modified at local solar noon maximum       kJ/m2       -1.0       latitude longitude       -1.0

last modified: 20 February 2024
data product contact: Jos van Geffen & Michiel van Weele & Ronald van der A
Copyright © KNMI / TEMIS