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Chinese Agricultural Science Bulletin ›› 2015, Vol. 31 ›› Issue (17): 222-227.doi: 10.11924/j.issn.1000-6850.casb15010128

Special Issue: 农业气象

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Characteristics Analysis of Wind in Zhangjiakou

  

  • Received:2015-01-19 Revised:2015-03-31 Accepted:2015-04-10 Online:2015-07-27 Published:2015-07-27

Abstract: In order to reveal the main characteristics of spatial-temporal distribution and change trend of wind direction and wind speed, and to provide the reference for rational utilization of resources and reduction of disaster in Zhangjiakou region, the wind observation data from 14 ground meteorological stations in Zhangjiakou region from 1960 to 2013 were statistically analyzed by mathematical statistics, linear fitting, climate trend rate method and so on. The results showed that the annual average wind speed in Zhangjiakou was 3.6- 4.1 m/s, higher than that in Baxia area, which was 1.8- 3.0 m/s. The annual average wind speed showed a declining tendency, with the reduction of 2.21 m/s in Bashang area and 0.92 m/s in Baxia area during the 54 years. The maximum decrease appeared in the 70's of last century. The annual average wind speed showed the type of‘spring strong, summer light’ , and the maximum and minimum of average wind velocity occurred respectively in April and August. The annual average wind speed decreased with the maximum rate in winter and the minimum rate in summer. The wind speed reached the maximum from 13:00 to 15:00 in Bashang area and about 15:00 in Baxia area and the smallest was at 5:00-7:00. The rate of growth and decline of wind speed in Bashang were greater than that in Baxia. The gale days reached 48.5 d/county in Bashang and 31.8 d/county in Baxia. The peak occurred between 1963 and 1974 and was reducing at a tendency of 9.4 d/10 a in Bashang and 7.1 d /10 a in Baxia. The prevalent wind directions were NW, N and W in Zhangjiakou region throughout the year, spring and winter had a consistent dominant wind direction, while the dominant wind direction in summer was in accordance with that in autumn. In summer, with the enhancement of warm air, the southerly and easterly wind increased.