Title: The GLO (GFCR Limb Occultation) Sensor: A New Sensor Concept for Upper Troposphere and Lower Stratosphere (UTLS) Composition and Transport Studies
Presenting Author: Richard Bevilacqua
Organization: Naval Research Laboratory
Co-Author(s): S. Bailey, S. Noel, B. Poche, J. Carstens (Virginia Tech), R. Bevilacqua, D. Korwan, F. Santiago, J. Bobak, S. Restaino (Naval Research Laboratory), C. Randall (University of Colorado and Laboratory for Atmospheric and Space Physics), L. Gordley, B. Marshall, M. Hervig (GATS, INC), and A. Marchant (Utah State University)

Abstract:
The GLO (GFCR Limb Occultation) instrument concept is a VNIR/SWIR solar occultation sensor designed to measure (all at < 1 km vertical resolution) O3, H2O, CH4, CO, HF, HCN, HCl, HDO, N2O, CO2 (for temperature), and aerosol from orbital altitudes. The vertical measurement range spans the entire middle atmosphere, but the sensor has been designed to particularly target transport and composition in the UTLS. GLO can be thought of as a miniaturized, updated version of HALOE (using 2D focal plane arrays instead of the single detector per channel approach used by HALOE), with the addition of three spectrally pure, broadband channels (0.45. 1.020, and 1.556 microns) for the measurement of stratospheric aerosol extinction. In addition, the VNIR channels will be used in combination with selected GFCR SWIR channels to provide information about aerosol composition, and integrated properties of the aerosol size distribution (effective radius, and volume and area density). With its small form factor and modest spacecraft requirements, GLO is well suited for constellation applications. We will describe one such implementation of GLO, on a mission concept we refer to as SOCRATES (Solar Occultation Constellation for Retrieving Aerosols and Trace Elements Species), to quantify the role of the UTLS in the climate system by providing a complete set of measurements that can be used to determine radiative fluxes in the UTLS, and to characterize the transport pathways that control the distribution of UTLS constituents. Under ESTO sponsorship, we are currently building a balloon-borne prototype version of the GLO sensor. The current schedule calls for instrument initial completion in Feb 2019, ground based testing March-July 2019, a first balloon flight opportunity in September 2019, and a potential second opportunity in September 2020. The instrument concept, measurement and data acquisition approach, and potential applications will be discussed.