The Long-term Change Characteristics Of Gale On Yellow Sea

Based on CFSR reanalysis dataset from Jan.1979to Dec.2009, this article does a comprehensive statistic analysis to the variable characteristics of force6+wind, of different direction, in different month, in the Yellow Sea area. The statistic shows that, average gale day of the Yellow Sea area has a decreasing trend. Over the years, the average of all sites is54.4days. In spatial distribution, north and southeast sea area has the most gale day. Furthermore, NNW has the most (7.8days), and south wind has the least (0.6days). Northwesterly and westerly day has an increasing trend, while other wind direction has a downward trend. Specific to each month, December has the most gale day (7.8days); June has the fewest (2.0days). In general, winter holds the most gale day (21.3days); spring and summer take the second place (12.6and13.8days), and summer holds the fewest (6.7days). Number of gale day from December to next April has an increasing trend, in other months, downward.Study to variation characteristics of force8+gale shows that, August has the most extreme wind day of the year. Tropical cyclone has a main relation to this.In winter, Yellow Sea area has the most northwesters; while in spring, southerlies increase month by month. Summer has the most southerlies, among which, mainly southeaster and southwester, and august has the most southwester.Analysis to gale day anomaly field of different wind direction during recent31years shows that, its first mode spatial distribution and time factor has a high consistency with the average spatial distribution of gale day and interannual changing curve. Wavelet analysis to time factor sequence of the first mode indicates that, though abnormal shock period of different direction gale day is generally2.5to5years, there are significant differences in the characteristics of obvious shock period and cycle.Analysis to the typical circulation feature of the Yellow Sea gale shows that, gale generation is intimately linked with cyclone location and strength, which obviously differs from the Bohai Sea. In winter, besides the northerlies caused by southward moving cold air, development of low pressure in the Sea of Japan may well brings about windy weather.