Collaborative Research: NSWP--Improvement and Real-time Updating of the International Reference Ionosphere with the Contribution of Auroral Electrons

合作研究：NSWP--极光电子贡献的国际参考电离层的改进和实时更新

• 批准号: 0819771
• 负责人: Yongliang Zhang
• 金额: $ 19.65万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-11-01 至 2013-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0819771&HistoricalAwards=false
• 关键词: Collaborative; Research; NSWP; Improvement; Real

The project has two main objectives: (1) Improve the International Reference Ionosphere (IRI) model by including the contributions from precipitating electrons to the model; this will result in better specification of the auroral E region in the model; and (2) Develop, implement, test, and validate an auroral boundary and/or Kp driven ability for nowcasting and forecasting of the polar E-region ionosphere. The IRI is an empirical model which is one of the most widely used by the upper atmosphere community to simulate the ionosphere for given conditions. However, its representation of the auroral region has been known to be somewhat compromised due to a lack of information on and observations for the polar region. One of the processes not well parameterized is that due to precipitating electrons, one of the major drivers of space weather in the ionosphere and thermosphere. The precipitation not only creates extra ionization in the high latitude ionosphere which leads to absorption and disturbances in radio communication, but also enhances the Joule heating which alters the thermospheric convection and composition. The altered thermospheric convection brings composition changes induced by Joule heating from high latitudes down to middle and low latitudes, even to the opposite hemisphere, and can cause global ionospheric disturbances. The precipitating electrons will be specified in the new IRI model by using a new Kp-dependent global auroral model that was developed with FUV image data obtained by the GUVI instrument on the TIMED satellite. The auroral model provides the global distribution of mean energy and energy flux of precipitating electrons. With these, one can then determine two key auroral E-layer parameters: the peak E-layer density (NmE) and the E layer height (hmE). The new NmE and hmE values will provide the data base for modifying the IRI E-region model to include the contribution from precipitating electrons. The FUV-based global auroral model will also enable better representation of the real time auroral oval conditions by providing information on the boundaries of the auroral oval and the location of the peak electron energy fluxes in different magnetic local time sectors. These will be represented as a statistical model for inclusion in the IRI. The auroral E-layer representation and the auroral boundaries in the improved IRI will be validated with electron density profile data from incoherent scatter radars such as Sondrestrom, EISCAT, and NSF's new Poker Flat Incoherent Scatter Radar, and with precipitating electron data from the DMSP F13-F17 particle detectors.

该项目有两个主要目标：(1)改进国际参考电离层模型，将沉淀电子对模型的贡献包括在内；这将导致在模型中更好地说明极光E区；以及(2)开发、实施、测试和验证极光边界和/或Kp驱动的能力，用于极地E区电离层的近距离预报和预报。IRI是高层大气社区在给定条件下模拟电离层的最广泛使用的经验模型之一。然而，由于缺乏关于极地区域的信息和观测，它对极光区域的代表已知在某种程度上受到了影响。没有很好地参数化的过程之一是由于电子的沉淀，这是电离层和热层中空间天气的主要驱动因素之一。降水不仅在高纬电离层产生额外的电离，导致无线电通信中的吸收和扰动，而且增强了焦耳加热，从而改变了热层对流和成分。热层对流的改变带来了焦耳加热引起的成分变化，从高纬度向下到中低纬，甚至到相反的半球，并可以引起全球电离层扰动。在新的IRI模型中，将使用一个新的依赖于Kp的全球极光模型来指定沉淀电子，该模型是利用定时卫星上的GUVI仪器获得的FUV图像数据开发的。极光模型提供了降水电子的平均能量和能流的全球分布。有了这些，就可以确定极光E层的两个关键参数：E层峰值密度(NME)和E层高度(HME)。新的NME和HME值将为修改IRI E区模型提供数据基础，以包括沉淀电子的贡献。基于FUV的全球极光模式还将通过提供有关极光椭圆形边界和不同磁性当地时间扇区中峰值电子能量通量位置的信息，更好地表示极光椭圆形的实时状况。这些将被表示为一个统计模型，以纳入IRI。改进的IRI中的极光E层表示和极光边界将使用Sondrestrom、EISCAT和NSF新的Poker Flat非相干散射雷达等非相干散射雷达的电子密度剖面数据以及DMSP F13-F17粒子探测器的降水电子数据进行验证。