Abstract:

Based on the meteorological data of Fujian Province from 1991 to 2020 and the investigation of the cold and freezing injury of passion fruit, this study determined four disaster-inducing factors of the cold and freezing injury of passion fruit with 2.5 °C as the critical temperature: the extreme minimum temperature during the cold process (X₁), the duration of temperatures ≤2.5°C (X₂), the harmful cold accumulation of temperatures ≤2.5℃ during the cold process (X₃), and the temperature drop amplitude when temperatures are ≤2.5℃ (X₄). These four factors were demonstrated to be representative in Fujian Province. After normalizing the data sequences of these factors, we applied principal component analysis to comprehensively simplify the four variables, thus constructing a comprehensive climate index for evaluating passion fruit cold damage. Using the natural breaks classification method, the index was divided into four severity levels: mild (-0.36≤W<-0.23), moderate (-0.23≤W<-0.08), severe (-0.08≤W<0.06), and extremely severe (W≥0.06). Climate data from Shaowu City were used for validation to confirm that the comprehensive climate index was consistent with actual damage observations. The research results provide practical reference value for agricultural production departments to conduct rapid disaster assessment, formulate disaster prevention and mitigation strategies, and carry out refined risk zoning.

Key words: passion fruit, cold and freezing injury, disaster-inducing factors, comprehensive climate index, grade division, principal component analysis, natural breaks classification method