Spatial-temporal Analysis of Wind Speed in the Bohai RimRegion during 1971-2013
Received date: 2015-04-10
Revised date: 2015-05-14
Online published: 2015-09-20
Based on daily maximum wind speed data from 60 meteorological stations, this study analyzed the spatial and temporal character of annual and seasonal wind speed during 1971-2013 in the Bohai Rim Region by the method of Linear trend estimation, Mann-kendall test, Wavelet analysis and IDW. Results indicated that: (1) The annual maximum wind speed was 6.35 m·s-1 and it showed significantly decreased trends with the decadal ratio of 0.423 m·s-1 in the Bohai Rim Region. Most meteorological stations showed downward trend and different spatial distribution. The declined degree was high in southern Bohai Rim Region while northern Bohai Rim Region was low overall. Besides, seasonal maximum wind speed also appeared significantly decreased trends and the contribution rates of spring and winter to annual maximum wind speed were higher. (2) Northerly winds (especially north northwest wind) and southerly winds (especially south southwest) were the main wind direction in this area. In addition, southerly winds were the prevailing wind in spring and summer while northerly winds were the main wind direction in autumn and winter. (3)The reason why the maximum wind speed decreased significantly was that the decreasing of the frequency of the daily maximum wind speed with a scale ≥5 respectively at the rate of 0.912, 0.671, 0.271, 0.076 d·a-1. Meanwhile, the frequency of the gale showed decreased trend with the ratio of 1.019 d·a-1. The period that gale day appeared relatively occured in winter and spring, especially in spring. 4) According to the annual mean frequency of gales in the Bohai Rim Region, four sub-regions can be divided. They are fewer gale region (<10 d), more gale region (10-50 d), much more gale region (50-100 d), frequent region (>100 d). Most parts of the Bohai Rim Region were fewer gale region and more gale region, and the most meteorological stations lies in more gale region while the lowest sites lies in frequent region. Besides, the annual average gale days show rapid growing trend in fewer gale region while it shows decreased tendency in more gale region, much more gale regions and frequent regions. In addition, maximum wind speed and gale day have several oscillating period.
Key words: maximum wind speed; gale day; wind direction; climate change; Bohai Rim Region
Cao Yongwang , Yan Junping . Spatial-temporal Analysis of Wind Speed in the Bohai RimRegion during 1971-2013[J]. Journal of Desert Research, 2015 , 35(5) : 1320 -1329 . DOI: 10.7522/j.issn.1000-694X.2015.00140
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