Abstract: Based on the data of the minimum air temperature in winter from 1961 to 2000 and of the frozen injury in Nanfeng County,the quantitative climate index for the frozen injury of Nanfeng tangerine(Citrus reticulata) was determined.The maps of climate risk for the frozen injury of Nanfeng tangerine were produced through small grids estimation technique on the grid by 25m×25m based on Geographic Information System(GIS).The land use map interpreted by the remote sensing was folded on maps of the frozen injury distribution.The synthesized maps were fractionized to obtain the maps of the climate risk distribution of the frozen injury for Nanfeng tangerine.Based on the risk regionalization,the frozen injury risk assessment was carried out.The results showed that the period of the climate risk for the light frozen injury in the main production areas with low altitude was from four to five years,while it was 20 and 40 years for the moderate and severe frozen injury respectively.The general income period of time of Nanfeng tangerine was for 15 years.Therefore,the climate condition for the tangerine growing in Nanfeng County was advantageous with relative small climate risk.

Key words: GIS technology, GIS technology, Nanfeng tangerine, Frozen injury, Risk assessment