Multispectral RS coupled with Web/mobile GIS would a better choice. RS data e.g. LandSat 8 possessing Near Infrared for identification of the target area and GIS for management or decision making/constant monitoring of the area.

Dear Asmat Ali

thank you so much for your useful opinion.

can you suggest best experience in this field.

Respected Behrooz Arastoo,

The best strategy perhaps would be to adopt a mix of multi-temporal as well as hyper temporal satellite imagery preferable supported by in- situ data. Mobile GIS must be employed to collect in-situ/ground truth data for quickly updating Web Spatial Databases being the core of internet/web GIS. Please let me know if more explanation is needed.

Dear Heidar

thank you so much

Dear Behroz , I think it is better use RS for monitoring,but before that you must structure a hierarchy for your goal within Multi Criteria Decision Analysis(MCDA). MCDA is powerful mean which focus on effective factor on drout

Dear Behrooz, we coordinated a Euro-Asian research project with a big component on drought and flood monitoring from remote sensing. Reports are available from our website, it may interest you : http://www.ceop-aegis.org/

Dear Jerome Colin

thank you for introduce your site .

where can i download data for country area ( i.e IRAN)

Dear Asmat,

You may look at some products from National Drought Mitigation Center (NDMC), some of which are based on RS and webGIS. The link is http://drought.unl.edu/MonitoringTools.aspx