• ARmaskDataSeries

ARmask - HMI Active Region Full-Disk Masks

This is a full-disk data product that currently identifies magnetically active pixels. The corresponding data product is hmi.Marmask_720s. There is a corresponding near-real-time data product, which is used to get timely space weather information, called hmi.Marmask_720s_nrt.

The mask is an integer (char, or BITPIX = 8) value at each pixel. Currently the integer can be one of three values: 0 for off-disk, 1 for quiet, and 2 for magnetically active. We hope to add a facula class, especially as the intensity images become more well-calibrated.

We use two image series, magnetograms (from hmi.M_720s) and intensitygrams (from hmi.Ic_720s), to determine class membership. This first iteration of the masks concentrates on active regions, so we rely on the magnetograms almost exclusively to compute the masks.