HARP - HMI Active Region Patches
Overview
A HARP (short for HMI Active Region Patch) is a coherent magnetic structure at the scale of a solar active region identified in one or more HMI line-of-sight magnetograms. HARPs are typically observed over an extended time interval (e.g., days), and tracked from one image to the next.
The HARPs in the data series hmi.MHARP_720s, which is indexed by an integer identifier, HARPNUM, and by T_REC. The HARP will often be linked with a NOAA Active Region. This data series provides pointers to information covering the entire disk passage for each HARP in the HMI catalog, as well as summary information such as per-region integrated flux, for each HARPNUM at each T_REC.
The data series tracks patches by associating information from other data series using links to maps and parameters computed for patches identified in individual magnetograms and intensity images. There are no actual data segments, just links to vector, line-of-sight, and intensity data and associated keywords.
HARP Data Series Keywords
# SERIES INFO
- DATANAME = HARP
- RETENTION = 0
- ARCHIVE = 0
- PRIMEKEYS = HARP_ID, T_REC
# PRIME KEY INFO
- HARPID, INT
- T_REC, TIME, Slotted
- T_REC_STEP = 12MIN
- T_REC_EPOCH = 1976.12.31_23:59:45.000_UTC
# PATCH INFO
PNUM, link, "PNUM", patch - The patch number of the HARP at T_REC in the Patches_Found dataseries
AREA, link,"AREA", patch - The AREA keyword of the patch
- I_MIN, link, "I_MIN", patch
FLUX, link,"FLUX",vecpatch - The computed flux of the vector field in the patch
- BTOT, link, "BTOT", vecpatch
- # OTHER information about the patches
# SEGMENT INFO - links
data: arp_map, link, patch - Pointer to the bitmap of the patch
data: blos, link, patch - Pointer to pointer to line-of-sight magnetic field data
data: BTOT, link, vecpatch - Pointer to pointer to vector magnetic field data
# LINKS
link: patch, "Patches_Found", static (because PNUM is arbitrary)
- link: vecpatch, "Vector_Patches", dynamic