Analysis of dusty and erosive winds in Kerman province in order to provide a calendar for forecasting and managing dust control

Wind erosion and dust are two different aspects of the same situation. They are the consequences of desertification, which their harmful effects in terms of health, environment and economy have become one of the important regional and global challenges especially in arid and desert areas. In this regards, Iran and especially Kerman province have highly suffered from them. Therefore in this study, we investigated the seasonal wind regime and analysis of the frequency, speed and direction of dust-producing and erosive winds of internal and external origin. The purpose of the study is to apply the results in programs and operations to combat desertification and reduce dust events by emphasizing their possible origin at the local and regional level for authorities. For this purpose, hourly data of wind speed and direction and dust codes recorded in six synoptic stations during the years 1986 to 2016 were analyzed. Graphical study of the speed and direction of general and dusty winds was drawn using WR Plot View 8.0.2 software. The possible sources of dust in the province and the beyond were identified by identifying and analyzing the speed and direction of internal and external erosive and non-erosive winds. The correlation between them as well as investigating the satellite images of dust events were examined. Finally, the monthly wind calendar regarding dust control was presented in three management levels of regional, provincial and local. The analysis of seasonal wind direction showed that in Kerman province, the prevailing winds in the northern parts blow from north and northwestern directions;, in central parts blow from west; and in southern part blow from southwest directions. The winds from southwest and west have faster speed. The results of homogeneity test in all stations showed that the average speed of internal dusty wind had a decreasing trend during the studied years and the speed of internal wind is 2.3 times greater than external winds and the cities of Bam and Anar are more affected by regional winds than other cities. This shows that the role of northern winds to transfer of particulate matter from neighboring provinces and remote areas to the province is greater. The result also showed 97.9% of internal events occurred as a dust event and the rest (2.1%) as a dust storm. Furthermore, in all stations, prevailing and vice-prevailing winds increased their frequency and speed due to atmospheric instabilities and local thermal cyclones and increasing the slope of the pressure gradient due to seasonal changes and solar radiation that caused dust events. In this regards, the winds with an average class speed of 6-10 meters per second had the highest frequency. Based on the correlations and satellite images, the possible sources of external dusts with a wind speed lower and greater than 6 m/s were identified outside and inside of the province, respectively. These types of winds should be considered for the management of fine dust control at the regional, provincial and local levels.