Adapted ECC ozone sonde for long-duration flights aboard boundary-layer pressurized balloons

Abstract

Abstract. Since the 1970s, the French space agency CNES has developed boundary-layer pressurized balloons (BLPBs) with the capability to transport lightweight scientific payloads at isopycnic level and offer a quasi-Lagrangian sampling of the lower atmosphere over very long distances and durations (up to several weeks). Electrochemical concentration cell (ECC) ozonesondes are widely used under small sounding balloons. However, their autonomy is limited to few hours owing to power consumption and electrolyte evaporation. An adaptation of the ECC sonde has been developed specifically for long-duration BLPB flights. Compared to conventional ECC sondes, the main feature is the possibility of programming periodic measurement sequences (with possible remote control during the flight). To increase the ozonesonde autonomy, the strategy has been adopted of short measurement sequences (2–3 min) regularly spaced in time (e.g., every 15 min). The rest of the time, the sonde pump is turned off. Results of preliminary ground-based tests are first presented. In particular, the sonde was able to provide correct ozone concentrations against a reference UV-absorption ozone analyzer for 4 days on a 15-min time base. Then we illustrate results from 16 BLBP flights launched over the western Mediterranean during three summer field cam- paigns of the ChArMEx project ( http://charmex.lsce.ipsl.fr): TRAQA in 2012 and ADRIMED and SAFMED in 2013. BLPB drifting altitudes were in the range 0.25–3.2 km. The longest flight lasted more than 32 hours and covered more than 1000 km. Satisfactory data were obtained when compared to independent ozone measurements close in space and time. The quasiLagrangian measurements allowed a first look at ozone diurnal evolution in the marine boundary layer as well as in the lower free troposphere. During some flight segments, there was indication of photochemical ozone production in the marine boundary layer or even in the free troposphere, at rates ranging from 1 to 2 ppbv h−1.

Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

“…(Table 4) and most balloons reached more than 30 km in altitude. Except for the first test balloon on 12 June, the payload of sounding balloons included a pair of meteorological sondes with temperature, humidity and GPS sensors allowing the retrieval of the position (±10 m), derived pressure (±1 hPa) and wind (±0.15 m s −1 ), respectively coupled, for certain flights (see Tables 4 and 5), to an ozone electrochemical sonde (Gheusi et al, 2015) and a LOAC OPC (Renard et al, 2015a, b). Balloon trajectories were confined within the area 39-41.2 • N in latitude and 3-5 • E in longitude.…”

“…The payload was composed of a GPS system, PTU instruments on the upper pole of the balloon, a LOAC instrument on the lower pole of the balloon and two solar radiation sensors for upward and downward solar flux measurements. In addition a BPCL equipped with a modified ozone electrochemical sonde (Gheusi et al, 2015) instead of a LOAC was launched in parallel of a LOAC balloon on 4 occasions on 16 and 17 June (BPCL B53 and B54, respectively), and on 2 July (BPCL B55 and B57). 14 BPCL balloons were launched in total between 16 June and 2 July 2013 (Table 5).…”