عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Drought is a complex natural phenomenon, which is due to the precipitation shortage and is one of the climatic challenging phenomena which has great and extensive impacts on human societies, environment and the world economy. During the recent years, various indices have been developed to detect and monitor drought. In the present paper, is to evaluate the drought phenomenon in Atrak River by using modified SWSI index.
Also, a first-order Markov chain model was used to simulate modified SWSI indexes, based on the estimated transitional probabilities and frequency distributions of river’s flow in the relevant stations. The results of this paper indicated that transition probability from a specified status to the same one is more probable than transition to other status (between 60 - 80 percent) and each of the stations, probably most of the time are at balanced status.
On the other hand, although some stations are more durable in drought conditions, but at the same rate, they spend in a very wet conditions for a short time, that more than before, reveals the importance of programming in operation parts.