摘要
冰雹天气是武威市多发的灾害天气之一。利用1961—2010年武威市5个气象站冰雹资料,采用统计学方法分析武威市冰雹天气的时空分布特征及变化趋势;选取1991—2010年5—9月武威市逐日NCEP再分析资料,对冰雹天气进行诊断分析并进行短时临近预报。结果表明:武威市冰雹有明显的地域特征,南部天祝山区冰雹日数远多于其他地区,占武威市冰雹总日数的76.1%。武威市逐年代及年冰雹日数总体呈减少的趋势,6—8月是冰雹的高发期,冰雹日数占全年冰雹总日数的80.2%。冰雹的日变化明显,11—19时为冰雹多发时段,集中发生时段为13—16时,冰雹的平均持续时间为10 min。结合当地实际可知,影响武威市的冰雹云大部分是由天祝县境内生成发展或从青海省移动来的。依据气流的南北配置将发生冰雹的环流形势分为3大类,分别为西北气流型、西南气流型和西风气流型。采用相关系数、经验预报和最大靠近原则等诊断分析方法,确定各类型冰雹的预报指标和阈值。诊断模式为冰雹的预报预警提供了客观有效的指导产品。
Hail is one of the most frequent disaster weather in Wuwei of Gansu province.Using hail data at five meteorological stations in Wuwei during 1961-2010,temporal and spatial distribution characteristics and changing trend of hail weather were analyzed by a statistical method.Besides,some diagnostic analyses and nowcasting of hail weather were made based on daily NCEP reanalysis data with the resolution of 1°×1°from May to September during 1991-2010.The results show that hail weather varies significantly in space,and a number of hail days are greater in mountain area of Tianzhu county than in other areas,accounting for 76.1 % of the total number of hail days in Wuwei.Annual and interdecadal hail days are in a deceasing tend.Most hails occur from June to August, which accounts for 80.2% of the total hail days.Daily variation of hail is obvious and most hails occur during 11：00 to 19：00,especially during 13：00 to 16：00,and mean duration of hail is about 10 minutes.According to the actual situation in the local area,most hail cloud impacting Wuwei generates and develops in Tianzhu county or moves from Qinghai province.Circulation patterns of hail weather are divided into three categories by north-south airflow configuration,namely,a northwest flow type,a southwest flow type and a westerly flow type.Forecast indi-ces and thresholds of different types′hails have been identified by diagnostic analysis methods including a correla-tion coefficient,an empirical prediction and a maximum proximity principle.This diagnostic mode can provide some objective and effective instruction products for hail forecasting and warning.
出处
《气象与环境学报》
2015年第2期82-88,共7页
Journal of Meteorology and Environment
基金
公益性行业(气象)科研专项"农田水分利用效率对气候变化的响应与适应技术"(GYHY201106029)
甘肃省干旱气象科学研究基金项目"石羊河流域干旱灾害风险评估及防御对策研究"(IAM201205)共同资助
