عنوان مقاله [English]
The wind is the horizontal displacement of air that is less than one meter per second. The wind is a dynamic phenomenon and has three main characteristics: intensity, direction, and frequency. Therefore, knowledge of wind characteristics in every area of importance is remarkable. The effects of global warming on temperature and precipitation at the global level over the past decades, many studies were considered; However, relatively little attention to climate change is wind speed. Wind speed changes can affect the energy of storms, shipping industries, as well as soil moisture, evaporation, and water resources; and it may even affect the evolution of dry and semi-arid environments. Also, a lot of research on wind and meteorology has shown that the performance of wind turbines is sensitive to climate change. Possible changes to the future wind regime have been widely considered under changing weather conditions; under global warming, the intensity and frequency of wind events are expected to change at the end of this century.
Materials and methods
The study area in this study of the eastern strip of Iran includes four provinces of Khorasan Razavi, South Khorasan, Kerman, and Sistan and Baluchestan. The study used wind speed data at a height of 10 meters, 10 synoptic stations with a daily statistical period of 2015-1985, which has 30 years of data; In choosing this station, in addition to proper distribution in the region, an attempt was made to select more stations in the station to be affected by the 120-day winds of Sistan. In this study, 10-meter daily wind speed data of the ERA-Interim version with a resolution of 0.125 × 0.125 degrees period of 1980-2015 were used; for the study area, 3772 pixels with an inter-pixel distance of about 12.5 km have been obtained. To evaluate the performance of simulated data against observational data; There are several indicators used in this study from the Root mean squared error (RMSE), Mean bias error (MBE), mean absolute error (MAE), and the coefficient of determination (R2). The non-parametric Man-Kendall method was used to investigate the trend of wind speed changes in research.
Results and discussion
The ECMWF ERA-Interim version has a high and good performance for wind speed. The results showed that the output of the mentioned base in all the studied stations is on average between 0.722 and 0.984. RMSE, MBE and MAE characteristics in Zahedan, Khash and Saravan stations are less than m / s1; In other words, the wind speed of ECMWF base in these three stations has the highest performance of the 11 stations studied. The monthly statistical assessment of wind speed in selected stations in eastern Iran during the statistical period studied (1985-1985) showed that the average wind speed is 3.56 m / s. The relationship between wind speed with negative altitude and positive longitude is significant at the level of 0.05. Also, the relationship between latitude and wind speed showed that this relationship is negative in the cold months of the year and positive in the warm months of the year. The average wind speed fluctuates greatly during the 30-year statistical period. The average wind speed varies between 2.82 and 4.57 m / s. The minimum and maximum wind speeds were calculated in December and July, respectively. The average 30-year wind speed at selected stations in eastern Iran was calculated to be 2 m / s. The maximum wind speed in eastern Iran has many fluctuations; autumn showed the lowest statistical value in terms of maximum wind speed; In December, the maximum wind speed was calculated to be 3.98 m / s. The maximum wind speed is increasing in all the studied months; From a statistical significance level, all the studied months except January, which, despite being increasing, are; But statistically, it is not significant at the level of 0.05 and 0.01; Other studied wind speed studies have a significant incremental trend at α = 0.01. The average wind speed in the study area is negative in 7 months (January, April, May, July, August, October and December) from the negative years and in 5 months (February, March, June, September and November). The maximum wind speed is January 4.42, February 4.86 and March 5.02 m / s. The next area to be obtained in the form of a fertile area in winter; Zabol is also the center of Iran's border with Afghanistan in the border areas of South Khorasan Province. The wind speed trend is positive at the time of onset (June, 0.79), the 120-day wind is positive and negative at the time of termination (October, -0.15).
The average wind speed in the study area (Khorasan Razavi and South Khorasan, Kerman and Sistan and Baluchestan provinces) during the long-term statistical period of 30 years (2015-1985) is 3.56 m / s; The minimum and maximum wind speeds are obtained in July and December, respectively; The reason for the increase in wind speed in July is due to the 120-day wind activity in Sistan, which started in June. The average wind speed in the study area is negative in 7 months (January, April, May, July, August, October, and December) from the negative year and in 5 months (February, March, June, September, and November). Investigation of wind speed process using non-parametric Man-Kendall (M-K) test; It showed that the wind speed trend in eastern Iran in the first month of June (June) 120-day winds showed an increasing trend (Z score of the Man-Kendall test 0.795) and in the last month (October) it decreased (-0.1152). ). Also, in July, when the wind speed is maximum, the average trend in the study area with a score of Z, 0.242 - is decreasing. Pearson correlation test showed that the relationship between wind speed and topography in the study area was statistically significant at 0.05; In contrast, the relationship between longitude and wind speed is significant in all studied moles at the alpha level of 0.05. In contrast, longitude and altitude in the study area did not show a uniform relationship between latitude and wind speed; this relationship is reversed for the cold months of the year and directly for the warm months. In October alone, the relationship between wind speed and latitude is not significant.