Abstract: In order to investigate the risk of low temperature freezing damage in winter for thermophilic vegetables in greenhouse in Fujian province, this study utilized the meteorological monitoring data from representative plastic greenhouses in Fuqing and Qingliu from December 2020 to February 2023, as well as assimilated land surface minimum temperature data during the same period. Regression models were developed for the minimum temperature inside the greenhouse under different weather conditions, such as sunny, cloudy, overcast and rainy. Based on data from the 66 meteorological stations in Fujian province from 1991 to 2020, daily minimum temperature inside greenhouse were inferred from December to February in previous years. Based on the low-temperature data inside the greenhouses, authors constructed a risk classification index system for freezing damage of thermophilic vegetables in greenhouses in Fujian. The weights of the indicators were determined by using the subjective-objective comprehensive weight method, and a risk assessment model for freezing damage was established to carry out the risk zoning of freezing damage in greenhouse for thermophilic vegetables in Fujian province. The results showed that: (1) the regression models for the minimum temperature in the greenhouse during winter under different weather conditions, including sunny, cloudy, overcast, and rainy, had R² greater than 0.75, and the absolute errors of the model validation were 0.6°C, 1.4°C, 1.0°C, and 0.5°C, respectively. (2) The low-risk area for cold and freezing damage of thermophilic vegetables in greenhouse mainly distributed in the coastal counties and cities south of Fuzhou with elevations below 200m. The medium-risk area mainly concentrated in the coastal areas of the north and the inland areas of the south with elevations between 200m and 500m. The moderate-risk area was mainly distributed in the middle and high altitude mountainous areas with elevations between 500m and 1000m in the southern inland and the coastal areas with elevations between 200m and 500m in the north, basically surrounding the areas with severe freezing damage and extending to lower elevations. The high-risk area mainly distributed in the areas above 1000m in Wuyi mountains, Jiufeng mountains, Daiyun mountains, Boping ridge, and Daimao mountain, where significant losses occurred and were not suitable for greenhouse thermophilic vegetable cultivation.

Key words: Greenhouse thermophilic vegetables, Temperature simulation, Cold and freezing injury, Risk, Fujian