early-warning system for desertification based on climatic and hydrologic criteria

The united nations’ convention on desertification encourages the participating countries to introduce criteria for developing early-warning systems (ews) in order to monitor and assess desertification. the objective of the present study was to establish an ews for desertification assessment in kashan plain, iran, using the methodology of practical and general applicability. designing ews requires a model to identify the influential criteria and areas vulnerable to desertification. the kashan plain’s ews relies on the iranian model for desertification potential assessment (imdpa) to establish desertification thresholds and generate desertification maps with geographic information systems (gis). the ews of kashan plain was designed to calculate hydrologic (groundwater level and electric conductivity of groundwater indices) and climatic (precipitation, transeau aridity, and drought indices) criteria and assess the degree of regional desertification. afterwards, the desertification intensity maps of criteria and indices were produced and overlapped. the ews was developed in areas most bound to be threatened by desertification. ews quantifies desertification data and thresholds to issue desertification assessments and warnings for management purposes. in the next step, client–server program was designed based on an algorithm defined by java programming language and implemented as a data collection, analysis, and response management system. whenever the thresholds exceed the defined limits, warning messages can be sent via sms or internet to relevant system managers for appropriate action.