Date Awarded
1997
Document Type
Dissertation
Degree Name
Doctor of Philosophy (Ph.D.)
Department
Physics
Abstract
Solar data from the Halogen Occultation Experiment (HALOE) were analyzed to determine the center-to-limb relative intensity and the vertical temperature profile for the quiet and active Sun over wavelengths from 2.4 to 10 {dollar}\mu{dollar}m. An algorithm that incorporated a nonlinear least squares procedure was developed that modeled the HALOE instrument during data acquisition. Data obtained from limb-to-limb scans along the solar equator on days of very low activity in May 1994 were analyzed to obtain coefficients of a function describing the relative intensity from center to limb. The relative intensities produced were precise to 0.1% (2{dollar}\sigma{dollar}) from the center to 0.25 arc min from the limb. The brightness temperature from the flux and the temperature as a function of monochromatic optical depth were also calculated from the coefficients. These quantities were normalized using published central intensities and compared to a semiemperical model of the photosphere. In general, the calculated temperature quantities were in good agreement with the model predictions; however, differences occurring between 2.4 and 3 {dollar}\mu{dollar}m suggest that the central intensities used here are low.;HALOE solar data were also investigated to obtain the intensity of a sunspot relative to the photosphere. A nonlinear least squares method was used to retrieve relative intensity information for a large sunspot on August 19, 1942. at each wavelength a one-component sunspot model proved sufficient to fit the measurements to the digitization level of the instrument. Sunspot/photosphere intensity ratios were calculated at each wavelength with an uncertainty of 2%. Compared with previous measurements at shorter wavelengths from 0.387 to 2.35 {dollar}\mu{dollar}m, the data exhibit the same general trend of larger ratios with increasing wavelengths; however, a larger than anticipated gap exists between the previous value at 2.35 {dollar}\mu{dollar}m and the HALOE ratio value at 2.45 {dollar}\mu{dollar}m. The photospheric and sunspot temperatures were calculated at each wavelength and show slight decreases with increasing wavelength. A steep drop exhibited by the previous measurements between 1.67 and 2.35 {dollar}\mu{dollar}m is not supported by HALOE values. Consideration of terrestrial atmospheric effects in the previous data could explain this discrepancy.
DOI
https://dx.doi.org/doi:10.21220/s2-ennb-0q57
Rights
© The Author
Recommended Citation
Spickler, Philip Todd, "Solar infrared relative intensity data from the Halogen Occultation Experiment" (1997). Dissertations, Theses, and Masters Projects. William & Mary. Paper 1539623905.
https://dx.doi.org/doi:10.21220/s2-ennb-0q57
