AMMA-SAT Presentation
logo_amma_sat.gifThe AMMA project offers an opportunity to develop the exploitation of satellite data and to make collaboration between specialist and non-specialist users. In this purpose the AMMA-SAT database is being developed to collect multiscale as well as multidisciplinary data related to the African Monsoon from all past and future satellites. It will then be possible to compare different types of data from different resolution, to validate satellite data with in situ measurements or numerical simulations. AMMA-SAT database main goal is to offer an easy access to satellite data to the AMMA scientific community.

Depending on the sensor type, various informations on atmospheric and surface properties could be derived over 10 - 20 years, whereas some other will be available only over a short period. For instance, using the existing and next satellites, the parameters that could be monitored over West Africa are:

  • the radiative budget at the surface and at the top of the atmosphere, the sea and land surface temperature;
  • the vertical profiles of temperature and humidity above land and ocean;
  • the large scale water vapor transport;
  • the variations of the tropospheric and UTLS ozone and other gases (NH4, CO, NO2);
  • the estimated wind from MSG measurements (from clouds and water vapor);
  • cloud classification;
  • vegetation coverage and estimation of soil moisture and soil structure;
  • the detection of precipitating clouds and rainfall estimation;
  • latent heat flux and surface wind over the Guinea Gulf;
  • fire detection.

However, new studies will have to be performed to increase the number of retrieved parameters, to improve their quality and validate them, and to combine satellite data with each other, with in situ measurements and with model simulations.

A number of satellites of interest have been flying for more than 10 years, and geostationary data have been available since 1980. Efforts must be engaged to exploit these data sets for monitoring seasonal to interannual evolution of the west Africa atmosphere and surface properties. Existing networks (the CATCH hydrology domain, MOZAIC ozone and other trace gas measurements, meteorological measurements) will be used to validate and possibly improve the retrievals. Comparisons with climate/meteorology models will be either used to complete validation of satellite retrievals, or in reverse, to evaluate the model simulations, and to initialize them. The relevant time/space resolution will range from a few tens of km up to 1 degree, and the area of interest will largely cover the west Africa, from the gulf of Guinea to the Sahara, and from East Atlantic to East Africa.

Areas of study

The data are available on different regions associated to resolutions. The regions are presented below as well the corresponding resolutions.

RegionAreaResolutions
Global

180° W / 180° E

90° S / 90° N

2.5°, 1.0°

Atlantic - Africa

60° W / 40° E

35° S / 35 °N

0.50 °, 0.25 °, 0.10°

West Africa

25° W / 25° E

5° S / 20 °N

0.1°, 0.05°, 0.01°

Local Areas



Basin of Oueme (Bénin)

1.30° E / 2.48° E

8.54° N / 10.12°

1 km, 100 m, 1 m, ...

Niamey area (Niger)

1.6° E / 3.0° E

13° N / 14° N

Basin of Gourma (Mali)

1° W / 2° W

14.3° N / 17.0° N

regions.png

Time period

The recent data will be treated in priority. The period 1997-2000 is the first objective. This period will be then extended to the actual years to treate the new sensors (ENVISAT, AEOS2, AQUA and MSG). The study period will then cover the years before 2009, last year of the AMMA program.

Temporal resolutions

The temporal resolution of each product will be chosen according to the resolution of the sensor used and the considered scale and temporal variability of the geophysical parameter. For exemple, for the large scale products, the temporal resolution can vary from some hours to one month.

Data types

The satellite data available on-line have the following caracteristics:

  • these are geophysical products (level2 or more), operationnal or specifically derived for AMMA-SAT.
  • the products are (re-)mapped on a regular lat/long grid.
  • the spatial and temporal resolutions are adapted to the AMMA-SAT resolution if needed

The data available off-line are (by request to This e-mail address is being protected from spam bots, you need JavaScript enabled to view it ):

  • data of level 2 with an original projection not corresponding to a regular grid
  • data of level 1 (radiances,brightness temperature, ...) used to derive a geophysical product specially for AMMA-SAT.
Last Updated ( Tuesday, 27 March 2007 )