Abstract: In order to reveal the atmospheric dynamic mechanisms of the catastrophic immigration of the Brown Plant Hopper(Nilaparvata lugens Sta.l),a great migration event of the Brown Plant Hopper occurred on 26th to 28th Aug.,2006 in the rice production areas of the Eastern China was taken as a case and the temporal-spatial migration pattern of the Brown Plant Hopper populations was analyzed by using ArcGIS9.0,based on the data of the daily lighting trap catches of the Brown Plant Hopper in China and the daily re-analyzed meteorological data in the Northern Hemisphere.The atmospheric dynamical background of this process was simulated by the high temporal and spatial resolution model WRF V2.2(Weather Research and Forecasting Model,version 2.2).Four physical fields,including the horizontal wind field,K index distribution,A index spatial pattern and vorticity field on 850 hPa isobaric surface,were chosen from the model output to represent the atmospheric dynamical characteristics.The results showed that: 1) The air streams of the horizontal wind field on the 850 hPa(approximately 1500m) could be used to describe the main migration directions of the Brown Plant Hopper populations.2) During the cardinal landing periods of the Brown Plant Hopper migration populations,the spatial patterns of K index and A index on 850 hPa isobaric surface displayed the atmospheric instability and qualitatively indicated the distribution of the main landing regions of the Brown Plant Hopper populations.As K≥35℃ or A≥10℃,or K≥35℃ and A≥10℃ at same time,it was favorable for taking-off and landing of the Brown Plant Hopper populations due to favorable conditions for the development of the vertical atmospheric movement.3) Before the massive migration of the Brown Plant Hopper population,the coherent negative vorticity either strong or weak on the 850 hPa isobaric surface in the landing areas of the Brown Plant Hopper populations appeared.It showed that there were the sinking airflows with certain strength in the regions.These sinking airflows were favorable for landing of the Brown Plant Hopper.

Key words: Brown Plant Hopper(Nilaparvata lugens Sta.l), Brown Plant Hopper(Nilaparvata lugens Sta.l), Migration, Weather Research and Forecasting Model(WRF), Atmospheric dynamical background, Numerical simulation