TOVS Product Information

TOVS Level 2

  • dewpoint temperature profile with 6 levels between 1000 - 300 hPa (approx. 0 - 10 km)
  • total column water vapor content (TWC) calculated from the humidity profile
  • European area (approx. 20 .. 80 N and 20 W .. 70 E)
  • horizontal distance between two retrievals: approx. 80 km
    temporal resolution: twice a day 
  • use of the standard retrieval package ITPP 5.21 
  • example profile data set (formatted in ascii) and a table of used abbreviations here
  • example image for a TWC data set
  • standard output format: generic binary format, binary2ascii FORTRAN77 or IDL routines are available

ATOVS Level 2

  • temperature profile with 40 levels on pressure levels 1000 - 0.1 hPa (approx. 0 - 65 km)
  • dewpoint temperature profile with 40 levels on pressure levels 1000 - 0.1 hPa 
  • total column water vapor content (TWC) calculated from the humidity profile
  • European area (approx. 20 .. 80 N and 20 W .. 70 E)
  • horizontal distance between two retrievals: approx. 80 km
  • temporal resolution: twice a day
  • use of the standard retrieval packages AAPP 3.0 and IAPP 2.0 

The AAPP homepage can be found at www.eumetsat.de -> Programmes under Development -> EPS -> AAPP.
Detailed information about the AAPP package are published in
The European ATOVS and AVHRR processing Package (AAPP)
Technical. Proceedings of the Tenth International ATOVS Study Conference,
Boulder, Colorado, USA, 27 Jan - 2 Feb. 1999.

Detailed information about the IAPP package are published in 
J. Li, W.W. Wolf, W.P. Menzel, W. Zhang, H-L. Huang, T.H. Achtor
Global Soundings of the Atmosphere from ATOVS Measurements:
The Algorithm and Validation
Journal of Applied Meteorology, Vol 39, 1248 - 1268, 2000

The generation of daily maps of total column water vapor content (level 3 product) is in preparation. This will be an interpolated product from the total column water vapor content.

Instrument Information

Both, TOVS and ATOVS are satellite borne vertical sounding instruments which consist of a radiometer for the visible to the infrared spectrum and a microwave module. Vertical profiles of temperature and humidity can be derived from the measured radiances.

TOVS was/is flown onboard NOAA 10 to NOAA 14. It is made up of three instruments: the High Resolution Infrared Radiation Sounder (HIRS), the Microwave Sounding Unit (MSU), and the Stratospheric Sounding Unit (SSU).  Detailed TOVS instrument information are available at the NOAA Polar Orbiter Users Guide

The Advanced TOVS (ATOVS) is flown on the NOAA satellites beginning with NOAA15 and is composed of three instruments as well: The next generation of HIRS (HIRS/3), the Advanced Microwave Sounding Unit AMSU-A (based on former MSU), and the Advanced Microwave Sounding Unit AMSU-B. Detailed ATOVS instrument information can be found in the NOAA KLM Polar Orbiter Users Guide

Quality Control

Quality checks are made on a monthly basis for the vertical profiles derived by TOVS and ATOVS. There are compared with ECMWF analysis fields. Please look at a typical example for temperature and dewpoint temperature comparisons for the TOVS system.

Besides the routinely comparisons with ECMWF fields, case study comparisons against several other data sources (radiosondes, other satellites, LIDAR) are under way.

Available Data

If you are interested in data please contact wdc@dlr.de. There might be restrictions if the required data amount is very high, but please contact us. An additional note: Our data is restricted to passes the sensor makes over Europe, and as such, global data is not available.