Other
Scientific paper
May 2003
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003spd....34.0708s&link_type=abstract
American Astronomical Society, SPD meeting #34, #07.08; Bulletin of the American Astronomical Society, Vol. 35, p.821
Other
1
Scientific paper
We studied the solar chromospheric rotation profile using full-disk Hα images of the Sun obtained at the Big Bear Solar Observatory (BBSO). The method is based on Local Correlation Tracking (LCT). As a unique feature the entire full-disk image is used, i. e., quiet sun as well as solar active regions, whereas most other methods rely on images of distinct individual features such as filaments, plages, and sunspots. Six months of Hα full-disk data sets from June to December 2001, which consists of 600 to 800 daily images at 30 s to 60 s cadence, have been processed and analyzed. The images were checked for a number of problems, including overexposure, underexposure, and skewed images. All images were normalized by having the solar disk recentered, the dark frame subtracted, and the limb darkening function calculated and subtracted from the image. The images are locally cross-correlated with each other to find the displacements between them. The angular velocities are projected onto the central meridian and a differential rotation profile is fitted to the data (either as Legendre polynomials or as polynomials in sin 2nθ , quad n=0,1, 2, ..., where θ is the heliographic longitude). The currently used settings in the processing of the six months data were optimized for both accuracy and speed. A number of different parameters were experimented with, such as various grid sizes, grid spacing, sampling window sizes, weighing functions and also different implementations of cross-correlation algorithms, to find the best combination.
This work was supported by NSF under grant ATM 00-86999, ATM 00-76602, and ATM 02-36945 and by NASA under grant NAG 5-9682.
Denker Carsten
Marquette William H.
Nenow Jeff
Smith Alex. G.
Varsik John
No associations
LandOfFree
Hα Full Disk Observations of Chromospheric Differential Rotation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Hα Full Disk Observations of Chromospheric Differential Rotation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hα Full Disk Observations of Chromospheric Differential Rotation will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-986510