基于县域单元的陕西日光温室蔬菜冻害风险特征及加温界线

低温冻害是陕西省干旱半干旱地区设施蔬菜越冬期的主要气象灾害，本研究明确了陕北和关中地区不同冻害级别指标，以县为单元提出了分析、计算设施蔬菜越冬期月尺度平均冻害频次及风险（ ）定量方法，分析了研究区域共68个县（区）冬季各月份多年平均冻害风险时间特征，研究结果表明：各地轻度冻害频次高于中度、重度，各地1、12、2月份各等级冻害出现频次依次减少，关中局地在12、2月未出现过重度冻害。陕北12、1月份0.6≤ ≤0.7，2月份0.5≤ ≤0.7；关中12、2月份0.1≤ ≤0.6，1月份0.2≤ ≤0.7。对各月冻害风险年份进行了分析，指出冻害风险不同年份间差异大，振幅变化明显。根据上述特征与陕西省设施蔬菜生产现状分冬季温室持续加温区、简易加温区、遇低温临时加温区这3个区域确定出了陕西设施蔬菜加温界限。该研究可提高温室防冻害能力，积极意义在于对设施蔬菜冻害风险管理对策方面进行了探索。

The Research on Risk Characteristics and Heating Type of Shaanxi Greenhouse Vegetables Frozen Injury Based on County Unit

The low temperature frozen injury is the main meteorological disaster of greenhouse winter vegetables in arid and semi arid areas of Shaanxi province.Quantitatively determine the risk of frozen injury and clear the heating boundary are significance to greenhouse design.Summarized the frozen indexes of different levels in northern area and Guanzhong area of Shaanxi.Proposed the monthly scales quantitative analysis and computation methods of the average risk of frozen injury of winter greenhouse vegetables based on county units.Analysed the time characteristics of the average risk of frozen injury of former winter months of 68 counties which in the study area.The results showed that the frequency of light frozen injury was more than the moderate and severe in all the counties and the frequency of frozen injury of each grade decrease successively from Jan.to Dec.and in the end of Feb.Severe frozen injury never appeared in some counties of Guanzhong area in Dec and Feb.The C ˉ value of Northern Shaanxi was 0.6-0.7 in Dec.and Jan.and 0.5-0.7 in Feb.The Cˉvalue of Guanzhong area is 0.1-0.6 in Dec.and Feb.and 0.2-0.7 in Jan.The analysis of frozen injury risk showed that it had a big difference in different years and amplitude significantly.According to those characteristics and the production status of greenhouse vegetables in arid and semi arid areas of Shaanxi province,divided Shaanxi greenhouse area into three heating zone：winter continuous heating zone,simple heating zone,low temperature temporary heating zone and determined the heating boundary.