Chinese Journal of Agrometeorology ›› 2015, Vol. 36 ›› Issue (01): 57-66.doi: 10.3969/j.issn.1000-6362.2015.01.008

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Study on Characteristics and Warning Signals of Chilling in May in Double Cropping Rice Area of Hunan Province

ZHANG Chao,WANG Li juan,LU Kui dong   

  1. 1School of Atmospheric Sciences,Nanjing University of Information Science and Technology,Nanjing210044,China;2Institute of Meteorological Science of Hunan Province,Changsha410007
  • Received:2014-06-03 Online:2015-02-20 Published:2015-05-21

Abstract: Based on daily temperature data of May from 66 meteorological stations in double cropping rice area of Hunan province during 1961-2013,the intensity index of chilling in May(IICM)was calculated,which was used to analyze the characteristics of temporal and spatial distribution and intensity of chilling in May.The method of physical decomposition of atmospheric variables was used to find possible precursors to indicate chilling process in May.The results showed that in the studied area the distribution of chilling in May was less in the south than that in the north and there were three main types: whole province,north middle Hunan,north Hunan.The intensity index of eighty percent of chilling processes in May were moderate or above and fifty percent of chilling processes in May effected on seventy percent of stations in double cropping rice area. During the study,fourteen processes occupied the negative center of temperature transient anomalies on the 850hPa level and the negative center of geopotential height transient anomalies on the 300hPa level,respectively.The negative center of temperature transient anomalies on the 850hPa level could be traced as precursors to indicate the occurrence of chilling process in May over 5-10 days in advance.The moving track of temperature transient anomalies had three,such as west road,northwest road and east road which was primary moving track.The chilling processes in May were north Hunan type mainly when the moving track was east road and generally they were north middle Hunan type when the moving track was north west road.

Key words: Chilling in May, Spatial distribution types, Physical decomposition, Temperature Anomalies, Precursors