Alan Burns, Richard Eastes*, Bill McClintock, The GOLD mission, and opportunities to enhance understanding of the thermosphere/ionosphere system through collaboration Alan Burns, Richard Eastes*, Bill McClintock, Dave Anderson, Laila Andersson, Mihail Codrescu, John Correira, Rob Daniels, Scott England, Scott Evans, Jerry Lumpe, Andrey Krymonos, Carlos Martinis, Dave Rusch, Stan Solomon, Tom Woods, Jens Oberheide,and Scott Budzein.

GOLD Status Launched on SES-14 - Jan 25, 2018 Ariane 5 rocket from French Guiana Detector doors opened - Jan 29, 2018 Transfer to GEO in progress Operations begin October 2018 GOLD Launch (Jan 25th, 2018)

Where is GOLD today! Epoch (UTC): 21 June Eccentricity: 0.1021118 inclination: 2.0499° perigee height: 31470 km apogee height: 40079 km https://www.heavens-above.com/

GOLD Science is Framed by 4 Questions Science Question 1. How do geomagnetic storms alter the temperature and composition structure of the thermosphere? Science Question 2. What is the global-scale response of the thermosphere to solar extreme-ultraviolet variability? Science Question 3. How significant are the effects of atmospheric waves and tides propagating from below on thermospheric temperature structure? Science Question 4. How does the nighttime equatorial ionosphere influence the formation and evolution of equatorial plasma density irregularities?

Daily Science Operations Commands are uploaded to the GOLD instrument on a weekly basis Uploads contain absolute and relative time sequences

L2 Data Products Validation 4/14/2019 L2 Data Products Validation Data Description [units] Validation Approach Lead Level 2  O/N2 Neutral composition. Ratio of O to N2 vertical column density [dimensionless] Coincident ICON O/N2; coincident GUVI and SSUSI data if available J. Correira Tdisk Thermospheric neutral temperature [K] Coincident ISR data and cross comparison with Texo S. Solomon  QEUV Solar EUV flux proxy   [mW/m2] Coincident Solar disk obs. S. Evans  Texo Neutral exospheric temperature [K] Coincident data from ICON; coincident GUVI and SSUSI data if available  O2 O2 number density profile [mol/cm3] Comparison with historical data and cross comparison with ICON measurements of N2 limb profiles J. Lumpe  Nmax Peak electron density  [electrons/cm3] Coincident data from Jicamarca ISR and ionosondes; COSMIC II, if available C. Martinis BOI, N2 Emission brightness [Rayleighs] Coincident satellite data (ICON, GUVI, SSUSI, etc.) W. McClintock

Data Products versus Science Requirements Notes/Constraints Requirement Realized* Images of Temperature 60 min Cadence 250 x 250 km2 Resolution Precision – 55 K 27 K Images of O/N2 Radiance Ratio 30 min Cadence Precision – 10 % 6.5 % Exospheric Temperature 100 km Vertical Resolution on Limb Precision – 40 K 22 K O2 Column Density at 160 km 2 % Vertical Resolution – 10 km 5.5 km Nmax F2 220 x 220 km2 Resolution 5.7 % *Realized values from retrievals using simulated data

GOLD Field of Regard Global C band beam

O/N2 and Ground Stations (2006 AGU storm) * ISRs ^ Ionosondes in Umass Lowell Database with 2018 data + GOLD location

Daytime Measurements of NmF2 and O/N2 over Port Stanley. Port Stanley Ionosonde Observations in Daylight * * * * * * * * * * * * * * * * * * * * * * * * * GOLD measurements of O/N2 over Port Stanley + + + + + + + + + + + + + + + + + + + + + + + + + + Satellite in LEO measurements of O/N2 over Port Stanley # …an unprecedented opportunity to compare composition with electron density and to provide a global context for these comparisons

The SES-14 satellite with GOLD on board is almost in its geostationary orbit GOLD is scheduled to provide regular data from October GOLD provides an unprecedented opportunity for comparisons with ground- and other space-based observations

GOLD Airglow Simulation (Solomon)

Forcing of the Thermosphere-Ionosphere Forcing the Upper Atmosphere Science Questions 1-4 Knipp, 2004