CMG: Statistical Wavelet Analysis and Indices Development of the Magnetosphere-Ionosphere Current System Observed by the Terrestrial Magnetometers

CMG：地磁计观测的磁层-电离层电流系统的统计小波分析和指数发展

• 批准号: 0413653
• 负责人: Jan Sojka
• 金额: $ 67.92万
• 依托单位: Utah State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0413653&HistoricalAwards=false
• 关键词: CMG; Statistical; Wavelet; Analysis; Indices

The currents flowing in the magnetosphere-ionosphere (M-I) form a complicated multi-scale geosystem that contains temporal and spatial scales from seconds to days over meters to global lengths. Ground-based magnetometers have long been the main tool to observe the M-I current system and a number of indices have been introduced to characterize the variations of specific current components. Due to the nature of this current system, the magnetic effects recorded on the magnetograms are multi-scaled, impulsive, and asychroneous with non-stationary frequency spectra. This leads to cross-talk among the traditional geomagnetic indices. In this statistics-geosciences collaborative research, the investigators develop new statistical techniques based upon wavelet analysis, which is especially suitable for analyzing signals that are impulsive and multi-scaled and have time-dependent spectra. Their new methodology is based on the analysis of a global distribution of magnetograms in the INTERMAGNET database. This investigation develops a technique for filtering multivariate time series with an objective of removing cross-talk signatures that contaminate the present-day geomagnetic indices. New approaches are developed for modeling time series with complex scaling and temporal structures, which may offer a simpler alternative to or complement various multi-fractal models. In addition to providing new insights into the structure of the magnetometer records, their methodology will be applicable to similar problems in which multivariate time series with intricate time-varying scaling and distributional properties need to be understood. Solar storm impacts in space and on Earth are usually adverse to humans due to enhanced radiation levels and also technology via electromagnetic charging-discharging and induced currents. These adverse effects are categorized as space weather. Civilian and defense weather centers specify and forecast the magnitude of their impacts to a broad range of commercial, military, and scientific users. Geomagnetic indices are the main measure of the strength of these impacts. For the first time in over 50 years, modern statistical and computational techniques are applied to resolving spatial and temporal structures in these indices on a global scale. This investigation develops improved magnetic indices of a significantly higher resolution. These new indices will be made available to the scientific and space weather forecast communities.

磁层-电离层（M-I）中流动的电流构成了一个复杂的多尺度地球系统，其时间和空间尺度从秒到天，从米到全球。 长期以来，地面磁力仪一直是观测M-I电流系统的主要工具，并引入了一些指标来表征特定电流分量的变化。 由于这个电流系统的性质，磁图上记录的磁效应是多尺度的，脉冲的，非同步的非平稳频谱。 这导致传统地磁指标之间的串扰。 在这项地球科学与地球科学的合作研究中，研究人员开发了基于小波分析的新统计技术，该技术特别适用于分析脉冲和多尺度信号，并具有时间相关的频谱。 他们的新方法是基于对INTERMAGNET数据库中磁图全球分布的分析。 这项调查开发了一种技术，用于过滤多变量时间序列的目标是去除串扰的签名污染当今的地磁指数。 新的方法被开发用于建模具有复杂尺度和时间结构的时间序列，这可能提供一个更简单的替代或补充各种多重分形模型。 除了提供新的见解的结构的磁力计记录，他们的方法将适用于类似的问题，其中多变量时间序列与复杂的随时间变化的缩放和分布特性需要了解。 太阳风暴在空间和地球上的影响通常对人类不利，因为辐射水平增加，而且通过电磁充放电和感应电流技术。 这些不利影响被归类为空间天气。 民用和国防气象中心向广泛的商业、军事和科学用户指定和预测其影响的程度。 地磁指数是衡量这些影响强度的主要指标。 50多年来，现代统计和计算技术第一次被用于在全球范围内解决这些指数的空间和时间结构。 这项调查开发了一个显着更高的分辨率改进的磁性指数。 这些新指数将提供给科学界和空间气象预报界。