The Impact of Climatic Extreme Events on Aeolian Geomorphic Process from Catastrophic Theory aspect (Case study: Coastal Plain of Western Makran)

Catastrophic theory provides an appropriate method for modeling the dynamical systems that are accompanied with sudden changes. Cyclone Gonu is a Climatic extreme event that had a significant impact on soil and vegetation of coastal deserts of southeastern of Iran. Such an extreme event at a lower intensity occurred in April 2013in Jask County (southeast of Iran). The aim of this research is to study the relationships between the exceptional climatic events and their affected changes in the soil and vegetation with wind erosion as a geomorphologic process. Research data included spatial distributions of landforms, precipitations data, Petrologic scores, terrain shape and roughness, wind velocity and conditions, soil and its non-life coverage factors, vegetation density and type, wind erosion forms, soil moisture, type and distribution of wind deposits and land use management in each of landforms. Maps of geology, topography, satellite images, equations of vegetation changes in relation to rainfall and IRIFR.EA model were used as tools also. By using of vegetation-rainfall equations and IRIFR.EA model, vegetation changes as a result of Gonu Cyclone extreme and rainfall events of April 2013, were estimated. Wind erosion was estimated also in the period before and after Gonu and rainfall events of April 2013. Initially the impacts of changes in vegetation status on wind erosion were calculated and then the new wind erosion conditions were estimated by using of vegetation-rainfall equations and IRIFR.EA model. The results indicate that although exceptional rainfall events grossly reduced wind erosion, but these changes are not so great that cause a change in wind erosion function. So in terms of wind erosion processes, these are not catastrophic events.