Operational informationOperational information
FAO RFE for SudanFAO & Sudan Meteorology AuthorityMauro Evangelisti &Stefano Alessandrini (FAO Consultant)
What is FAO-RFE?What is FAO-RFE?
FAO-RFE is a system that collects, stores, processes several basic data to estimate the rainfall over an area with limited ground information
FAO-RFE uses the available ground information for the day-based local day-based local calibrationcalibration
Residuals for NDVI computed as a function of (a) RFE and (b) ECMWF. The residuals can be interpreted directly as rainfall over- or underestimations. Areas with less than 200 mm of average annual rainfall and water bodies have been masked out (in white).
O. Rojas, F. Rembold, J. Delincé & O. Léo (2011): Using the NDVI as auxiliary data for rapid quality assessment of rainfall estimates in Africa, International Journal of Remote Sensing, 32:12, 3249-3265
RFE-NOAA ECMWF
FAO-RFE general schemeFAO-RFE general scheme
Infrared meteosat data~ 3 km resolution
GOES Index
Humidity and precipitable water profiles from ECMWF
Daily Rainfall field3 km resolution
ECMWF rainfall data~ 25 km resolution
Daily Rainfall field3 km resolution
Weighted linear combination GTS (gauges)
Rainfall dataWeights determination
Preliminary CombinedRainfall field
3 km resolution
FinalMerged Rainfall field
3 km resolution
MPE (Eumetsat) Infrared and Microwave
Estimation 3km resolution
Daily Rainfall field3 km resolution
ValidatedRainfall data
Interpolation
Local Calibration
FAO-RFE productsFAO-RFE products
1 day RFE
10D RFE
Monthly RFE
2007 2010
Climatology
36 dekads 12 months
Reference Maps
Real Tim
e Estim
ate
FAO-RFE versionsFAO-RFE versions
FAO-RFE is available at two levels:– continentalcontinental– country-basedcountry-based
(e.g. Sudan)(e.g. Sudan)
FAO-RFE customizationFAO-RFE customization
Customization works at several levels:– input datainput data– forecast modelforecast model– 00Z or 06Z based00Z or 06Z based– algorithmsalgorithms– already existing work flowalready existing work flow– output formatsoutput formats– user interfaceuser interface
Difference between FAO RFE Difference between FAO RFE (continental product) and FAO RFE (continental product) and FAO RFE at country levelat country level At the country level GTS measurements can be used together with
local data So, at the country level both the global calibration and the local
calibration are performed only with specific measurements over a territory with a limited extension.
At the continental level the calibration processes are performed over a larger area, including stations far from the country and this can result in a loss of reliability for a specific country
At the country level all the power has been given to the measurements and the RFE daily estimate is forced to be equal to the measurements at the gauges locations
At the continental level we have less control about the quality of the measurements therefore some rainfall data are rejected (if is to much different from the RFE estimate) and the local calibration forces less strongly the RFE estimate towards the measured data
Case study SUDAN:16 Aug 2007Case study SUDAN:16 Aug 2007Station Local Calibration
FAO-RFE user interfaceFAO-RFE user interface
- Time Aggregation Selector- Reference Maps Viewer- Zoom facilities
- Point and Click query
- Regular (lat,lon) grids output at different resolutions in GeoTiff and Idrisi Raster
FAO RFE (continental)10 days 21-30/06/2011
FAO RFE (SUDAN version)10 days 21-30/06/2011
The estimate done at National level using more station data leads to a lower rainfall values in general over Sudan territoryThe effect is more evident on a 10 days period
FAO RFE (continental)Monthly 06/2011
FAO RFE (SUDAN version)Monthly 06/2011
The estimate done at National level using more station data lead to a lower rainfall values in general over Sudan territory
Advantage of FAO-RFEAdvantage of FAO-RFE The main advantage will be for the country that
will be able to do/manage his own rainfall estimates
incentive of improvement of network stations The country will has the possibility to improve it
when more meteorological stations will be available
The accuracy should be high when compare with the methodological approaches that only considerer the GTS stations.