Magnetometer Data Viewer

Reeve Observatory - Anchorage, Alaska  USA
Geographic coordinates: 61.19928 °N : 149.95652 °W
Geomagnetic coordinates: 61.63 °N : 262.89 °E

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This page automatically reloads the latest magnetogram every 2 minutes

Sensor: 3-axis, X (North-South, blue), Y (East-West, red), and Z (Vertical, green) - Geographic Coordinate System

SAM-III with (3) sensors commissioned 11 October, 2010

Original SAM with (1) sensor commissioned 27 May, 2009 and decommissioned 11 October, 2010

Read the magnetogram as follows:

The horizontal scale is a 24-hour time scale in Coordinated Universal Time (UTC). Just above the horizontal axis are colored bars indicating the K-index for each period (this actually is a pseudo-K-index because it is calculated on each of the X, Y and Z components instead of the horizontal component [vector sum of X and Y]). The highest K-index of the three appears at the top of the chart. The colors of the K-index bars are: Green: K3 and below, Yellow: K4 and K5, and Red: K6 and above.

A red alarm bar may appear just below the horizontal axis. The alarm is triggered when the magnetic field fluctuations reach a preset threshold within 20 minutes. For the above chart, the threshold is K5. A rapidly changing field indicates high probability of visible aurora.

The vertical scale shows magnetic induction (magnetic flux density, B) in nanoTeslas. The chart is normalized each day at 0000 UTC wherein the magnetic induction of all three components, Bx, By and Bz, are zeroed relative to the value at 2359:59 UTC the day before. The vertical scale is automatically adjusted (auto-scale).

The color of each trace is indicated for Bx (Blue), By (Red) and Bz (Green) in the lower-left corner of the chart.

The chart legend includes the city, state and country, geographic coordinates, date ( and time. Note: geomagnetic coordinates of the station are given at the top of this page.