SSAI In The News

SSAI employee, Yonghoon Choi, participated in the SABRE (Stratospheric Aerosol processes, Budget and Radiative Effects) mission as part of the Diode Laser Hygrometer (DLH) instrument team. The SABRE mission is a NOAA-sponsored study using the NASA JSC WB-57F aircraft and operating the DLH instrument during missions to measure water vapor in arctic high altitudes.  

Stratospheric aerosols are an important component of Earth's albedo and therefore part of the Earth’s energy balance. Stratospheric aerosols provide surface area for heterogeneous chemistry, which can lead to stratospheric ozone loss. Acquiring a comprehensive database of stratospheric aerosol, trace gas and dynamical observations to establish the baseline state and background variability of the stratosphere is essential to (1) developing a complete understanding of stratospheric dynamical and chemical processes that determine aerosol microphysics, radiative properties and heterogeneous chemistry (2) evaluating the stratospheric response to natural and anthropogenic perturbations including climate change, volcanic eruptions, and potential climate intervention activities and (3) strengthening the scientific foundation to inform policy decisions related to regulating global emissions that impact the stratosphere (e.g., ozone depleting substances, rocket exhaust) and the potential injection of material into the stratosphere to combat global warming (climate intervention). 
 

This project is an extended airborne science measurement program utilizing the NASA WB-57 high-altitude research aircraft to study the transport, chemistry, microphysics and radiative properties of aerosols in the upper troposphere and lower stratosphere (UTLS). Complete execution of flight campaigns would provide extensive detailed measurements of aerosol size distributions, composition, and radiative properties along with relevant trace gas species in different regions and seasons, which are critical for improving the ability of global models to accurately simulate the radiative, dynamical and chemical impacts of changes to stratospheric aerosol loading. (https://csl.noaa.gov/projects/sabre/) 

DLH was part of a payload designed to provide detailed information on the chemical composition of the stratosphere and provided real time high frequency water vapor data during flight and post-flight, which shows fine scale variability, to the science team. The final data accuracy is expected to be ~5%, even down to the lowest values observed, precision at 1 Hz <0.1% or 0.1 ppmv. 
 
Yonghoon Choi participated in the 2023 SABRE campaign by operating and maintaining the DLH instrument during the mission to measure water vapor on the NASA WB-57. This mission has flown primarily from Eielson AFB in Fairbanks, Alaska (February 21 to March 24, 2023), with a small number of flights from Ellington Field in Houston, Texas (February 9 to February 18, 2023). During the SABRE 2023 campaign, the aircraft probed the core of the Arctic polar vortex as well as other relevant features of the Arctic winter stratosphere.  Preliminary data were archived, and Yonghoon Choi will be involved in collecting the post-flight final data and a detailed data analysis of water vapor in the high-altitude region.