SH31C-2425
Estimating Coronagraph Visibility Functions – Progress Report
Wednesday, 16 December 2015
Poster Hall (Moscone South)
O C St Cyr1, Hong Xie2, Daniel Duncan2, David F Webb3, Russell Howard4 and Joseph B Gurman5, (1)NASA Goddard Space Flight Center, Code 670, Greenbelt, MD, United States, (2)Catholic University of America, Washington, DC, United States, (3)Boston College, Chestnut Hill, MA, United States, (4)U.S. Naval Research Laboratory, Washington, DC, United States, (5)NASA Goddard Space Flight Center, Greenbelt, MD, United States
Abstract:
Annual estimates of the coronal mass ejection (CME) rate have been well-documented and are quasi-continuous since the mid-1970s based on both groundbased and spacebased observations. However, coronagraphic observations from a single viewpoint are unable to detect all CMEs because they are limited by the properties of Thomson-scattered photospheric radiation by coronal electrons. To overcome this limitation and to extend the CME rate estimates beyond a single instrument, Webb & Howard (1994) formulated the “visibility function” as an instrument-specific calibration factor. Recently we have begun an investigation comparing visibility functions for SOHO LASCO, STEREO COR1/COR2, and the groundbased Mauna Loa Solar Observatory Mk3/Mk4 coronagraphs in order to extend the historical record of the CME rate. With the launch of the twin STEREO spacecraft in late 2006, we are able to use the combination of multiple instruments viewing from longitudinally-separated locations to obtain new estimates of the global CME rate. We provide a progress report on this activity.
