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一、引言在春季3—5月,甘肃省河西地区经常出现大风天气过程,其中偏西大风占区域性大风的四分之三。朱乾根等已从天气学角度说明了锋面及强锋区过境时,由于气压场的配合,会引起地面风速增大。牛志敏通过对大风个例分析发现,高层有高有效位能集中,才能形成具有高动能的急流 相似文献
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The spatial variation and diurnal fluctuation of sea surface wind over the Qiongzhou Strait were described using verified datasets from automatic weather stations on board a ferry, buoys, and on the coast. Results are as follows: (1) On average, sea surface wind speed is 3–4 m/s larger over the Qiongzhou Strait than in the coastal area. Sea surface wind speeds of 8.0 m/s or above (on Beaufort scale five) in the coastal area are associated with speeds 5–6 m/s greater over the surface of the Qiongzhou Strait. (2) Gust coefficients for the Qiongzhou Strait decrease along with increasing wind speeds. When coastal wind speed is less than scale five, the average gust coefficient over the sea surface is between 1.4 and 1.5; when wind speed is equal to scale five or above, the average gust coefficient is about 1.35. (3) In autumn and winter, the diurnal differences of average wind speed and wind consistency over the strait are less than those in the coastal area; when wind speed is 10.8 m/s (scale six) or above, the diurnal difference of average wind speed decreases while wind consistency increases for both the strait and the coast. 相似文献
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1 气象灾害防御机制现状
气象灾害防御包括人们为减轻灾害而采取的各种社会活动和工程措施,主要是指为了减轻气象灾害损失所建立的气象灾害防御组织管理体系、运转机制和行动机制,制定的防御规划和应急预案,以及为减轻气象灾害所实施的工程性措施和非工程性措施,所采取的各种行动和活动。 相似文献
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EVALUATION OF TEMPERATURE RECORDS OBTAINED BY AWS IN HAINAN PROVINCE AND ADJUSTMENT OF CLIMATOLOGICAL TIME SERIES 总被引：1，自引：0，他引：1
Based on the parallel air temperature data of automatic sounding and manual observations at 16
weather stations in Hainan province from 2004 to 2005, a comparative analysis and evaluation is made for
validity according to relevant standards. The results indicate that there are daily and seasonal differences
between temperature observations recorded by automatic weather stations (AWSs) and with conventional
methods. The reasons for the differences are the systematic error, the sensitivity of the two types of
instruments to the environmental temperature change, the difference of the observation time and the effect
of solar radiation. Because the long-range data were obtained from manual observation, an empirical
conversion formula between the temperature records obtained by the instruments is provided for
continuous use of the climate data after the changes in instruments. 相似文献
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基于DEM的农业指标温度分析——以甘肃河东地区为例 总被引：2，自引：1，他引：1
基于甘肃河东地区61个气象近30a(1971—2000年)的气温资料计算了≥0℃、≥10℃积温;利用地理信息系统(GIS)技术对≥0℃和≥10℃积温进行了数据栅格化.结果表明:甘肃省河东地区≥0℃积温、≥10℃活动和有效积温与经度和海拔的相关性达到极显著水平,推算积温与实际积温的相对误比较小,数据栅格化的≥0℃积温、≥10℃活动和有效积温空间分布比实际积温更突显地域差别,这种巨大差异对农业结构的多样性发展提供了条件;气候变暖使热量资源增加,对农业的影响还与降水资源有关系. 相似文献
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