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 T

ime

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.