{"title":"高纬度电离层大尺度和中尺度等离子流涡度统计的空间变化及其对电离层等离子流模型的影响","authors":"G. Chisham, M. P. Freeman","doi":"10.1029/2024JA032887","DOIUrl":null,"url":null,"abstract":"<p>The ability to understand and model ionospheric plasma flow on all spatial scales has important implications for operational space weather models. This study exploits a recently developed method to statistically separate large-scale and meso-scale contributions to probability density functions (PDFs) of ionospheric flow vorticity measured by the Super Dual Auroral Radar Network (SuperDARN). The SuperDARN vorticity data are first sub-divided depending on the Interplanetary Magnetic Field (IMF) direction, and the separation method is applied to PDFs of vorticity compiled in spatial regions of size 1° of geomagnetic latitude by 1 hr of magnetic local time, covering much of the high-latitude ionosphere in the northern hemisphere. The resulting PDFs are fit by model functions using maximum likelihood estimation (MLE) and the spatial variations of the MLE estimators for both the large-scale and meso-scale components are presented. The spatial variations of the large-scale vorticity estimators are ordered by the average ionospheric convection flow, which is highly dependent on the IMF direction. The spatial variations of the meso-scale vorticity estimators appear independent of the senses of vorticity and IMF direction, but have a different character in the polar cap, the cusp, the auroral region, and the sub-auroral region. The paper concludes by discussing the sources of the vorticity components in the different regions, and the consequences for the fidelity of ionospheric plasma flow models.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6000,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA032887","citationCount":"0","resultStr":"{\"title\":\"The Spatial Variation of Large- and Meso-Scale Plasma Flow Vorticity Statistics in the High-Latitude Ionosphere and Implications for Ionospheric Plasma Flow Models\",\"authors\":\"G. Chisham, M. P. Freeman\",\"doi\":\"10.1029/2024JA032887\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>The ability to understand and model ionospheric plasma flow on all spatial scales has important implications for operational space weather models. This study exploits a recently developed method to statistically separate large-scale and meso-scale contributions to probability density functions (PDFs) of ionospheric flow vorticity measured by the Super Dual Auroral Radar Network (SuperDARN). The SuperDARN vorticity data are first sub-divided depending on the Interplanetary Magnetic Field (IMF) direction, and the separation method is applied to PDFs of vorticity compiled in spatial regions of size 1° of geomagnetic latitude by 1 hr of magnetic local time, covering much of the high-latitude ionosphere in the northern hemisphere. The resulting PDFs are fit by model functions using maximum likelihood estimation (MLE) and the spatial variations of the MLE estimators for both the large-scale and meso-scale components are presented. The spatial variations of the large-scale vorticity estimators are ordered by the average ionospheric convection flow, which is highly dependent on the IMF direction. The spatial variations of the meso-scale vorticity estimators appear independent of the senses of vorticity and IMF direction, but have a different character in the polar cap, the cusp, the auroral region, and the sub-auroral region. The paper concludes by discussing the sources of the vorticity components in the different regions, and the consequences for the fidelity of ionospheric plasma flow models.</p>\",\"PeriodicalId\":15894,\"journal\":{\"name\":\"Journal of Geophysical Research: Space Physics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2024-07-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA032887\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Geophysical Research: Space Physics\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1029/2024JA032887\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ASTRONOMY & ASTROPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Geophysical Research: Space Physics","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1029/2024JA032887","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
摘要
了解和模拟所有空间尺度电离层等离子流的能力对实用空间天气模式具有重要意义。本研究利用最近开发的一种方法,从统计学上分离大尺度和中尺度对超级双极光雷达网(SuperDARN)测量的电离层流动涡度概率密度函数(PDF)的贡献。首先根据行星际磁场(IMF)方向对 SuperDARN 涡度数据进行细分,然后将分离方法应用于在地磁纬度 1°、磁当地时间 1 小时大小的空间区域编制的涡度 PDF,覆盖北半球大部分高纬度电离层。利用最大似然估计法(MLE)通过模型函数拟合所得 PDF,并给出了大尺度和中尺度成分的最大似然估计法估计值的空间变化。大尺度涡度估计值的空间变化由电离层平均对流排序,而电离层对流高度依赖于 IMF 方向。中尺度涡度估计器的空间变化似乎与涡度和 IMF 方向的感应无关,但在极盖、尖顶、极光区和次极光区具有不同的特征。本文最后讨论了不同区域涡度成分的来源,以及对电离层等离子体流模型保真度的影响。
The Spatial Variation of Large- and Meso-Scale Plasma Flow Vorticity Statistics in the High-Latitude Ionosphere and Implications for Ionospheric Plasma Flow Models
The ability to understand and model ionospheric plasma flow on all spatial scales has important implications for operational space weather models. This study exploits a recently developed method to statistically separate large-scale and meso-scale contributions to probability density functions (PDFs) of ionospheric flow vorticity measured by the Super Dual Auroral Radar Network (SuperDARN). The SuperDARN vorticity data are first sub-divided depending on the Interplanetary Magnetic Field (IMF) direction, and the separation method is applied to PDFs of vorticity compiled in spatial regions of size 1° of geomagnetic latitude by 1 hr of magnetic local time, covering much of the high-latitude ionosphere in the northern hemisphere. The resulting PDFs are fit by model functions using maximum likelihood estimation (MLE) and the spatial variations of the MLE estimators for both the large-scale and meso-scale components are presented. The spatial variations of the large-scale vorticity estimators are ordered by the average ionospheric convection flow, which is highly dependent on the IMF direction. The spatial variations of the meso-scale vorticity estimators appear independent of the senses of vorticity and IMF direction, but have a different character in the polar cap, the cusp, the auroral region, and the sub-auroral region. The paper concludes by discussing the sources of the vorticity components in the different regions, and the consequences for the fidelity of ionospheric plasma flow models.