The potential climate productivity refers to the proper highest biological yield or agricultural yield in per unit area when climatic resources such as the light, heat, and water are fully used while the other conditions such as soil, nutrient, carbon dioxide, and so on are under the most suitable status. Gansu Province is the main dry land farming agricultural region in northwestern China. Because of the low natural productivity, its agricultural production still partly relies on climatic conditions, mainly depending on the environmental factors such as the light, heat and water resources and their changes. It has very important theoretical and practical significance in reasonably using of climatic resources, fully displaying the potential climatic productivity, improving productivity application level,and providing valuable advices for agricultural production to study the potential climatic dynamics and its main influence factors.
Based on the temperature and precipitation data in 69 meteorological stations during 1971 to 2007 in Gansu province, the temporal and spatial distribution of the potential temperature productivity, precipitation productivity, and climatic productivity and their dynamics were analyzed using Miami model and Thornthwaite Memorial model. At the same time, the spatial and temporal dynamics characteristics of potential climatic productivity in the recent 40 years were analyzed using the EOF function and the Mann-Kendall statistical method. Also, the driving forces to the dynamics of potential climatic productivity in Gansu province were analyzed. The results showed that the potential temperature productivity was significantly increased while the potential precipitation productivity was slightly decreased in the recent 40 years with their conversion year in 1997and 1994. The mean potential climatic productivity in Hexi Corridor, Gannan Grassland, Middle Gansu Plateau, Eastern Gansu Plateau, Southern Gansu province were 313.36, 741.72, 763.85, 867.52, 982.86 kg · hm^-2 · a^-1, respectively. Besides, the potential climatic productivity was obviously increased from 1979 to 1996 with its conversion year in 1997, and the conversion year was 1997 while significantly and continually decreased from 1997 to 2007. The correlation coefficients between the potential climatic productivity and the mean annual precipitation, and between the potential productivity and the mean annual temperature were 0.94 and 0.04, respectively. Therefore, the precipitation was the key factor to determine the potential climate productivity in Gansu province. The spatial distribution of potential climatic productivity in Gansu province was decreased from southeast to northwest, the minimum and maximum values marked in Dunhuang with 74.52 kg · hm^-2 · a^-1 and Huixian with 1094.39 kg · hm^-2 · a^-1, respectively, while the mean potential climate productivity of the whole province was 733.86 kg · hm^-2 · a^-1. According to the average distribution of potential climatic productivity, the maximum value was obtained in Southern Gansu province, followed by Eastern Gansu Plateau, Middle Gansu Plateau, Gannan Grassland and Hexi Corridor in order. furthermore, both temperature and humidity increasing were beneficial to the agricultural production in the whole province with the temperature increasing effect of 5.51 25.34 kg · hm^-2 · a^-1 and the humidity increasing effect of 27.89 34.49 kg · hm^-2 · a^-1, and the humidity increasing effect was much more significant, especially having significant promotion to agricultural development in Hexi Corridor. Therefore, the precipitation was the main driving force to influence the potential climate productivity in Gansu province. In addition, the warmer and drier climatic changing trend can aggravate to the reduction of the potential climate productivity.