Abstract:
The rice planthopper is a major pest harming the rice in China and many Asian countries. Relationships between atmospheric circulation characteristic indices and ratios of the occurrence area of rice planthopper in China are fully analyzed using 74 atmospheric circulation characteristic indices in various time-periods within last January to August. 52 key atmospheric circulation characteristic factors influencing the ratio of the occurrence area are selected, their main influencing periods are July to August, and the next last June to June. The order of their influencing extent is successively subtropical high category, polar vortex category, trough category, and other index category. Among the 52 key atmospheric circulation characteristic factors, there are 35 subtropical high factors and 12 polar vortex factors, accounting for 67% and 23% of the total, respectively, and therefore the ratio of the occurrence area of rice planthopper is mainly determined by subtropical high and polar vortex factors. 11 key atmospheric circulation characteristic factor indices directly influencing the ratio of the occurrence area of rice planthopper are decided, among them 6 indices are obviously indicative of climate characteristics for four occurrence levels (1-4) of rice planthopper. 7 prediction models for ratios of the occurrence area of rice planthopper used at the beginning of the months from March to September are established. Their historical simulated results are good, and the accuracies of extended range prediction in 2003 are 85.6%、90.5%、90.5%、90.4%、90.9%、93.2%、96.3%, respectively. In order to understand the possible influencing mechanism of atmospheric circulation on the occurrence area of rice planthopper, relationships among monthly temperature, precipitation, and sunshine duration of different time-periods from January to November in the rice planted area, key atmospheric circulation characteristic indices and the occurrence area of rice planthopper are analyzed. The results show that relations among them are close. The atmospheric circulation influences the temperature, precipitation, sunshine in the riceplanted area, thus affecting the ratio of the occurrence area of rice planthopper. The influencing periods of meteorological factors on the occurrence of rice planthopper are mainly winter and summer.