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Proposal ID Moses_5

Date of Proposal
96/04/19

name
D Moses

institute
NRL

address
Code 7660.1
Washington,DC 20375

email
moses@louis14.nrl.navy.mil

phone

fax

proposal
EIT Observing Program:

Synoptic He II 304 A Full Disk Irradiance Observations

Investigators:

J.W. Cook and D. Moses (cook@hrts.nrl.navy.mil;
moses@louis14.nrl.navy.mil)

Brief Scientific Summary:

The EIT synoptic program will obtain three full disk 304 A
images per day. After calibration, the full disk intensity is
found from summing the intensity in all pixels within 1 solar
radii of the disk center; we will ignore off-limb intensities
from spicules, prominences, etc., if we confirm that they
represent a small extra contribution to total flux. The full disk
flux (irradiance) is then pi less than I greater than disk.

We will compare the synoptic record of these fluxes with the
results of a solar irradiance model which uses the daily NSO/Kitt
Peak full disk magnetogram. This model is based on a functional
relationship between surface intensity, for this application in
He II 304 A, and the absolute value of magnetic field strength,
to calculate full disk irradiance. Based on the solar position
angle of each surface element, the model takes into account the
center-to-limb variation in intensity and radializes all
longitudinal fields in the magnetogram.

This model has already been applied to the solar 1600 A and L
alpha intensities observed by the SUSIM and SOLSTICE irradiance
monitors on the UARS satellite. We would develop the specialized
B vs. intensity relationship for He II 304 A.

The EIT observations provide a long term record for comparison
with model predictions at a temporal resolution which is finer
than the daily SUSIM/UARS observations which we have thus far
used for irradiance observations at other wavelengths. Since the
primary data product from EIT is a resolved disk image, we can
also directly observe the short time scale development of solar
fine scale features and compare with the resultant irradiance
variations on the same time scales.

Suggested EIT Observations:

The daily synoptic observations of He II 304 A, for days when an
NSO/Kitt Peak magnetogram is available. We may also investigate
using the MDI magnetograms if they are available to us, and
comparable in quality.

inside_collab

consortium
yes

title
EIT Observing Program:

Synoptic He II 304 A Full Disk Irradiance Observations


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