Chase is a class of 2015 graduate from Aiea High School on Oahu. He will be finishing his double major in Astrophysics and Math at the University of Hawai’i at Manoa in the fall of 2019. He hopes to go on to graduate school to pursue a graduate degree in Astrophysics and continue to do research. When he’s not in class, he is actively involved in ASUH, the undergraduate student government at UH Manoa, or using his free time to build computers and looking for the best ramen spot on Oahu.
Home Island: Oahu
Institution when accepted: University of Hawaii at Manoa
Akamai Project: Creating an Extensive Spectral Database for the DKIST Flux Budget
Project Site: Daniel K. Inouye Solar Telescope – Pukalani, Maui
Mentors: David Harrington, Andre Fehlmann
Project Abstract:
The Daniel K. Inouye Solar Telescope (DKIST) currently is using the Simple Model for Atmospheric Radiative Transfer of Sunshine (SMARTS) to provide spectral information used in the flux budget. To be ready for the science use cases, the flux budget requires a more comprehensive assessment of the impact of atmospheric effects. This project will focus on creating a database of atmospheric transmission and spectral irradiance data that includes a number of atmospheric observing conditions. The current SMARTS – based flux budget is derived from a single nominal atmosphere with no dependency on variables such as airmass and columnated water vapor. To address this, the MODerate resolution TRANsmission (MODTRAN) program was used. This program simulates electromagnetic radiation through the atmosphere and was used to conduct a variable assessment of aerosol optical depth, water vapor content, and airmass on transmission and irradiance of sunlight. Using empirical data, I found that aerosol optical depth made no significant contribution, while assessing the impacts of water vapor content at the 10th, 50th, and 90th percentile for yearly values was sufficient for modeling atmospheric transmission. Airmass values were taken at increments of 5 degrees of solar elevation ranging from 5° to 90°. I created a database of transmission and irradiance spectra ranging from 0.200 microns to 30.0 microns with using different combinations of these observing variables in MODTRAN. To readily access this information, I wrote retrieval script to retrieve data from a specified set of spectral range and certain observing conditions. Additionally, this script can also interpolate data points that were not sampled and will convolve and sample the spectrum with a given instrumental profile. The band model for MODTRAN limits resolution of this database at spectral resolving power (R) of about 100,000 in the visible range of wavelengths, while existing measured databases, such as the NSO atlases, reach an R ~ 1,000,000. With this consideration and in future use cases, the database and retrieval tool can be used on any instrument performance calculator at DKIST, and can be used to help the current and next generation of instruments.