基于测站空间加密的青海高原降水分布特征研究

Research on the Precipitation Distribution Characteristics of Qinghai-Tibet Plateau Based on the Space Station Encrypted

青海高原地形地貌复杂多样,降水量空间差异大、局地性强,长期以来,由于地面气象观测站稀疏,所观测到的降水量代表性较差,造成“大网捕小鱼”的无奈。文章利用2012年~2014年5月至10月青藏高原50个国家基本气象站点降水资料和全省445个加密自动站的降水资料,分析夏半年(5月~10月)测点加密后的降水空间分布特征得出:(1)自动气象站点加密后,夏季的最大降水中心和降水量均发生了明显的变化;(2)青海省极端降水主要出现在7月和8月,大暴雨出现的几率比较小,暴雨主要出现在加密测站中,极端降水往往具有降水时间短、强度大、容易造成灾害的特点;(3)无论是强降水天气过程,还是一般性降水天气过程,降水中心均出现在加密站中,而不是出现在基本观测站中。分析结果有助于对青海高原降水气候特点的再认识,可为降水的精细化预报提供有价值的参考信息。

Qinghai Plateau enjoys a complex and diverse topography, which leads to huge spatial differences of precipitation and strong regional feature. For a long time, the ground meteorological stations have been few and scattered,resulting in an awkward situation of “to catch small fish with big net”. That is to say, the precipitations observed are poorly representative. A comprehensive analysis of the features of the spacial distribution of precipitation observed from densified stations can help to recognize the climate features of precipitation of Qinghai Plateau, so as to provide valuable reference information for the fine forecast of the meteorological element of precipitation. This thesis mainly analyses the precipitation features in summer months(May to October), using the precipitation statistics of 50 national basic meteorological stations and 445 densified stations in Qinghai Province from the year of 2012 to 2014. According to the the local standard code of meteorological disasters issued by Qinghai Quality and Technology Supervision Bureau, when the amount of precipitation within 24 hours is more than 25mm, it is heavy rain;when over 50mm, it is rainstorm;and when over 100mm, it is downpour. We can draw these conclusions through analysis:(1)After densifying the automatic meteorological stations, both the center of the maximum rainfall and precipitation in summer changed obviously.(2)The extreme precipitation of Qinghai Province mainly occurred in July and August. The chance of downpour appeared very small, and rainstorm mainly occurred in the densified stations. In most cases,the extreme precipitations were with short time and strong intensity, which is easy to cause disasters.(3) No matter in the weather process of heavy or moderate precipitation, the center of precipitation was always in the densified stations, but not basic stations.