Title: Study of Solar Irradiance Variability Using PSPT Observations Ground-based Study of Solar Irradiance Variability Using the RISE/PSPT
Author: G. de Toma
Affil: NCAR/HAO
Email: detoma@hao.ucar.edu
Authors: P. Fox, R. Meisner, O.R. White, K. L. Harvey
Affils: HAO, HAO, HAO, SPRC
Abstract: The high precision and accuracy of the images from the Precision Solar Photometric Telescopes (PSPT) in the CaII K line at 393.4nm and in two photospheric continuum bands at 409nm and 607nm can be used to study photospheric and chromospheric structures with an unprecedented accuracy and coverage.
In this work, we present our preliminary results on the decomposition of PSPT images into the major components responsible for solar irradiance variability, i.e. sunspots, faculae/plages, active network, and quite Sun, and we describe our future work on PSPT image decomposition.
We have used PSPT observations taken at the Mauna Loa Solar Observatory between 1998 and 2001, during the ascending and maximum phase of solar cycle 23. Images at different levels of solar activity have been selected and decomposed using an automatic identification scheme based on a series of gaussian fits to the image intensity distribution function. The time series of the structures identified with this technique are used to discuss solar variability over solar short- and long-time scales.