MMS Ozonesonde Wind and Temperature Comparison during CRAVE

MMS - Ozonesonde Wind and Temperature Comparison during CR-AVE T. P. Bui, J. Dean-Day, C. Chang, R. Castaneda NASA-Ames Research Center H. Voemel University of Colorado -- CIRES

Data Sources • Profiles of WB-57 MMS 1 -Hz U, V, T and P during descent to Juan Santa. Maria Int Airport • Vaisala RS-80 radiosonde collected GPS position (latitude/longitude), T and P during Ozonesonde ascents from Heredia, Costa Rica • Heredia is in close proximity to Juan Santa. Maria airport (10 km distance separation) • Sondes launched within 1 hr of WB-57 takeoff or landing on 11 flights (10 descents, 1 ascent)

Data Specifications • Meteorological Measurement System: Static Pressure (+/- 0. 3 mb) Static Temperature (+/- 0. 3 K) Wind Velocity (+/- 1. 0 m/s) • Vaisala RS-80 Radiosonde: Static Pressure (+/- 0. 1 – 1. 0 mb) Static Temperature (+/- 0. 2 K) (Temperature corrected for radiation/ventilation effects) • Combined Uncertainty at same time/location: Temperature (+/- 0. 5 K)

RS-80 Wind Calculation • Deriving Horizontal Winds from Sonde: GPS position (latitude/longitude/altitude) reported every 1 - 2 seconds during ascent to ~ 30 km altitude Time rates of GPS latitude/longitude define U, V midway between GPS altitude levels U, V at reported levels estimated from spline interpolation of instantaneous U, V to each GPS altitude level Resulting U, V profiles were highly variable; Wind profiles subjected to simple vertical averaging to remove scales < 100 m (approximately 20 sec during 5 m/s ascent)

Ideal Comparison • MMS and Sonde BOTH report GPS position: > Interpolate MMS data to ozone sonde GPS altitude > Minimum temporal/spatial separation • Ideal conditions for MMS–RS 80 comparison: > All profiles are within 2 hours in time > Spatial separation < 60 km > In generally horizontal homogeneous environment (tropics)

Comparison Summary MMS warmer than RS-80 by 0. 30 +/- 0. 20 K MMS Wind Velocity slightly lower (~ 0. 65 m/s) but uncertainty is larger than mean differences • Pressure Difference is within RS-80 max error (1 mb) Sonde pressure is lower by 0. 7 mb; larger uncertainty at lower altitudes scale with pressure.