WAMI is the acronym for Wavelet Analysis of Magnetosphere and Ionosphere, a research project funded by NSF award DMS-0413653 Statistical Wavelet Analysis and Indices Development of the Magnetosphere-Ionosphere Current System Observed by the Terrestrial Magnetometers  (mathematical geosciences).

Currents flowing in the magnetosphere-ionosphere (M-I) form a complex multiscale system in which a number of individual currents  connect and influence each other. The variabilities of these currents are closely connected to various nonlinear dynamic M-I processes, such as magnetic storms and substorms, driven by the solar energy, Fig 1.

Figure 1: Artist's rendition of the impact of the enhanced solar wind on the magnetosphere.

Among the various observational means, the global network of ground-based magnetometers stands out with unique strengths of global spacial coverage at all time scales. About a hundred terrestrial geomagnetic observatories form a network, INTERMAGNET, designed to monitor the variations of the M-I current system. Modern digital magnetometers record three components of the magnetic field in five second resolution, but the INTERMAGNET's data we use consist of one minute averages, i.e. 1440 data points per day per component per observatory.

An example of a one day long magnetometer record is shown in Fig. 2. It shows a signature of an event known as a substorm. Substorms occur over polar regions, and are associated with the Auroras.

Figure 2: Substorm signature recorded at College, Alaska

Figure 3: The Aurora Borealis, or Northern Lights, shines above Bear Lake,
Eielson Air Force Base, Alaska

The main focus of our research has been the development of a cleaner index of storm activity. We have done extensive work on deconvoluting the signature of the symmetric ring current, depicted in Fig. 4, which is the largest storm time feature.  This is a difficult task because magnetometer records contain nonlinearly superimposed signatures of many currents. We developed new statistical techniques, based on wavelet and functional data analysis, that have brought us closer to this goal.

Figure 3: Artist's rendition of the symmetric ring current.