## 1 Introduction  
Radiation frosts happen frequently in the middle and lower reaches of the Yangtze River, China, leading to huge losses of famous tea production [1,2]. Generally, radiation frost occurs at the specific meteorological characteristics with a clear and calm sky, and a high relative humidity. During a typical frost night, heat in the form radiant energy, is easily lost from the underlying surface to the sky. Under a clear night-time sky, there is much more heat radiated out from the surface than received which results in the decrease of air temperature [3,4]. A temperature inversion will form when the air temperature falls faster near the radiant surface. The sensible heat from the soil and air near the radiant surface is reduced, which causes a net loss of energy from surface. Based on the energy balance in the plant-soil-atmosphere system, sensible heat flux downwards from the air and upwards from the surface soil to replace the heat losses. Dew point temperature is the temperature at which water vapor condenses into liquid water [5]. Generally, relative humidity is a relative measurement of how humid the air is, the dewpoint temperature is an absolute measurement of how much water is in the air. When warm air contracts with a cooler surface, water vapor will condense. With the further decrease of air temperature to frost point, the water vapor will be frozen [4,6]. A light frost event will happen when the nighttime temperature is below 0 \({}^{\circ}\)C. A heavy frost occurs after a period of more than four consecutive hours of air temperature that is below \(-4\)\({}^{\circ}\)C [4]. Several methods have been attempted to predict frost events in recent decades, but many involve the empirical relationship to the dewpoint temperature (\(T_{d}\)). [PERSON] pointed that frost may happen when the \(T_{d}\) is less than 6 \({}^{\circ}\)C, and more likely to happen as it is below 0 \({}^{\circ}\)C in Victoria [7]. In Canada the nocturnal minimum temperature is deduced as equal to \((T_{max}+T_{d})/2\) minus a correction parameter related to the wind speed and cloudiness. \(T_{max}\) is the highest temperature in the previous day (FAO). However, radiation frost is caused by kinds of specific and complicated meteorological conditions. Simply using the dew temperature to present the radiation frost has certain limitation and inaccuracy. Generally, frost warning systems and models are developed using meteorological variables, such as maximum and minimum temperatures, dewpoint temperature, cloud cover, precipitation and average wind speed [8, 9, 10]. [PERSON] et al. [11] statistically analyzed the historical data of late frost occurrence in Zhenjiang of China between March and April from 1979 to 2008 and established the prediction models based on the seasonal disasters grey method. The results found that grey prediction model had the excellent accuracy with the ratio between posteriori errors less than 0.35 and the model accuracy above 0.95. However, the model was limited to be used for predicting the first and last frost occurrence dates. [PERSON] et al. [12] attempted using logistic regression (LR) and decision tree (DT) techniques to develop the prediction models for spring frosts in Korea. The average values of hit rate and probability of detection were all high in both of LR and DT. However, only eight limited meteorological variables, such as the minimum temperature, difference between maximum and minimum temperature, grass minimum temperature, dewpoint temperature, cloud cover, mean relative humidity, minimum relative humidity and wind speed, were used as variables for the prediction models. It was not accurate because those models ignored the radiation meteorological data. The energy budget balance is closely associated with the radiation in a typical radiation frost night. Radiated energy is the main form of the energy absorbed and lost in the eco-system. LR and DT techniques indeed had a good predict accuracy with simply and linearly data.