عنوان مقاله [English]
Study of the wind field of the meteorological Stations to detect the dust and salt prone storm and soil erosion was the concern of the meteorologists, natural researchers and agro meteorologists. To show the wind power in sand storm creation and sand displacement; the researchers used the wind rose, storm rose and sand rose which is a simple and efficient method to detect the wind's role on dust storm. Many Iranian researchers; used the Friberger,s method in which Ahmadi and et el(2001and 2002) are the frontiers who used the dust rose from 1994 to 2013 over many Iranian provinces. In this study the power of wind in dust and salt displacement is discussed in Orumiya Lake basin.
The aim of this research is detection of the potential annual sand and salt transfer by wind around Ormia Lake due to its drying. To do that, the continuous three hourly wind data of the Oromia, Mahabad, Salmas and Piranshahr meteorological stations in west Azarbaijan and Bonab, Maragheh, and Tabriz stations from their stablishment till the end of 2014 in east Azarbaijan are statistically analyzed and then the diagrams of the wind rose, storm rose and sand rose are depicted by suitable soft wares.
Materials and methods:
In this study the wind speed and direction data of the Met. stations around the Orumiya Lake are received from Iranian Meteorological Organization(from starting activity up to 2014). Regarding the adequate historical length and quality of data, the Tabriz, Orumiye, Bonab, Maragheh, Piranshahr and Mahabad in Orumiye Lake basin are selected as the representative stations of the area. The monthly, seasonal and annual wind roses of these stations are depicted and then analyzed using the WRPLOT software. Since the frequencies of calm winds was high, they are deleted and then using the threshold wind speed of 6m/s, the storm roses are depicted and then analyzed. Applying the Friberger method, the sand rose software was designed and after depicting the monthly, seasonal and annual sand rose, the wind sand displacement ability in these stations are analyzed.
Results and discussions:
Study the sand rose figures in meteorological stations around the Orumiya Lake shows that the sand displacement in Tabriz is strong from March to August, moderate in February, September, October and November and weak in March and April. In Orumiya it is moderate in March and April and feeble in other months. In Maragheh dust displacement power in July and August is very strong ,in March, June and September it is strong; in September it is feeble an in other months is moderate. In Bonab the sand displacement power is moderate from February to August and in other months it is feeble. In Mahabad the sand displacement power is very strong in January till April and in October till December it is strong, in June and September it is moderate and in other months it is feeble. In Piranshahr it is very strong from January till April, strong in September till December, moderate in June and feeble in other months. IN Salms the sand displacement power is very strong in March and April, strong in May till July, feeble in November and December and it is moderate in other months.
The results of the study detected the potential of sand and salt displacement in the east and west Azarbaijan provinces. Regarding the position of the different stations around the salt and dust basin of the Ormiya Lake and the net annual transfer of dust and sand, it can be concluded that Mahabad, Maragheh, Bonab, and Tabriz cities are more under danger of sand and salt transfer and their out coming air and soil pollutions. In other stations either due to topographical blocking or lack of sand and salt sources, the probability of air and soil pollution lowers.