大气低频振荡对中国褐飞虱灾变性迁入的影响

In the recent ten years,brown planthopper (BPH),Nilapavata lugens (St?l), has located a position of the Number One in the rice pests of world rice production for the high outbreaking frequencies, the extensive occurrence areas and the serious endangering degrees.The complicated atmospheric background is one of key facotors influencing on the catastrophic immigrations of BPH's populations. In the past researches on the atmospheric mechanisms of BPH's catastrophe, the focus has been putting on the analysis on the effects of the short-term atmospheric dynamical processes in the catastrophic immigrations of BPH and the discussion of the influence of long-term climate changes on the periodic outbreaking of BPH's immigration. But little attention had been paid on the impacts of the low-frequency atmospheric oscillations on the large-scale immigration of BPH and it had brought about some patterns of BPH's immigration processes has been unable to ascertain and the catastrophic mechanisms of these processes has been unable to expound. Based on the analysis on the BPH's immigration peaks of different rice-growing regions in China since 1979, in this project, the meteorological data in the same time will be used to determine the weather events and climate processes influencing the occurrence of BPH's immigration peaks and the processes that the low-frequency atmospheric oscillations affected the large-scale immigrations of BPH will be screened. Especially, the influencing patterns of these screened processes will be analyzed from the commonality and the catastrophic characteristics will be discussed from the special individuality. Combined with the NCEP reanalyzed meteorological data, the Regional Climate Model version3 (RegCM3) and the Weather Research and Forecast model for version 3.2(WRF3.2), will be used to the numerical simulations of the screened processes, the key atmospheric physical variables influencing the BPH's catastrophic immigrations will be diagnosed from the output results of the model and the influence mechanisms of the low-frequency atmospheric oscillations on the catastrophic immigrations of BPH's populations will be clarified. All of the above researches will provide a scientific basis for the systematic interpretation on the impact of atmospheric movement processes on BPH's catastrophic immigrations and the med-long-term early warning of BPH's catastrophes.

近十年来，褐飞虱因爆发频次多、发生面积大、危害程度重而成为世界水稻生产上的头号害虫。复杂的大气背景是影响其灾变性迁入的关键因素，以往国内外学者在短期大气动力过程对褐飞虱灾变性迁入的影响和长期气候变化对褐飞虱周期性爆发的影响上作了较多探讨，但在大气低频振荡对褐飞虱大规模迁入的影响方面涉猎极少，使得一些迁入过程的规律至今无法摸清，灾变机理无法阐释。本项目拟在过去35年我国各稻区褐飞虱迁入峰分析的基础上，根据同期气象资料，确定出大气低频振荡影响其迁入的过程，从共性角度剖析其影响规律，从个性角度探讨其灾变特征；并结合气象再分析资料，应用RegCM3模式和WRF-ARW3.2模式对上述过程进行数值模拟试验，诊断出影响迁入的关键大气物理量，阐明大气低频振荡对褐飞虱灾变性迁入的影响机理。研究可为不同尺度大气运动过程对褐飞虱灾变性迁入影响的系统阐释及褐飞虱中长期灾变预警提供科学依据。

以往国内外学者在大气低频振荡对褐飞虱迁入影响方面涉猎极少，使得一些迁飞规律至今无法摸清，灾变机理无法阐释。本项目根据 1979-2015 年中国 105 个植保站的褐飞虱灯诱资料、同期 NCEP/NCAR全球气象再分析资料，筛选出大气低频振荡影响褐飞虱迁入的过程，分析迁入量与低频大气振荡之间的关系；利用 HYSPLIT 轨迹模型对迁入降虫区的褐飞虱种群作后向轨迹分析，应用天气和气候模式对这些过程进行数值模拟，诊断出了影响迁入的关键大气物理量，探讨了大气低频物理量场对褐飞虱迁飞路径、虫源地和降落区的影响机理。研究表明：（1）我国南方不同稻区褐飞虱迁入量分别表现出10-20d、20-30d和30-60d的低频振荡周期。其中华南和西南稻区4-6月以10-20 d的准双周振荡为主，7-10月以30-60d的准双月振荡为主；江岭稻区和江淮稻区6-10月以30-60d的准双月振荡为主。（2）与低频迁入虫量显著相关的是850hPa和925hPa高度上的低频风场、低频位势高度场和低频垂直速度场。（3）在北迁和南迁不同的低频振荡季内，850hPa和925hPa高度上不同的盛行风向形成不同的北迁和南迁迁入峰。（4）在低频位势高度场的高压区、脊前槽后和下沉气流区易形成褐飞虱迁入峰，而在低压区、槽前脊后和上升气流区内则迁入量极少。（4）褐飞虱种群的后向轨迹分析结果进一步验证了迁入不同稻区的褐飞虱种群轨迹、虫源地和降虫区与低频风场的盛行基本一致，低频位势高度场和垂直速度场对虫源起降和输送起了重要的动力作用。. 此外，还针对不同稻区褐飞虱虫源地、迁飞路径和降虫区梳理，衔接短期大气胁迫对褐飞虱迁入影响、大气低频振荡对褐飞虱迁入影响、东亚夏季风对褐飞虱迁飞节律和种群动态影响及气候变化对褐飞虱迁入影响的研究，构建了不同时效和尺度的褐飞虱灾变预警模型，研发了考虑害虫生物学参数的水稻迁飞性害虫迁入峰预警技术和轨迹分析软件，研究提出的理论假说及形成的相关技术不仅为不同尺度大气过程对褐飞虱灾变性迁入影响的系统阐释奠定了理论基础，而且为我国褐飞虱的延伸期预报和中长期灾变预警提供了重要的实践依据。