10 Oct 2023
 | 10 Oct 2023
Status: this preprint is currently under review for the journal AMT.

Pico-Light H2O: Intercomparison of in situ water vapour measurements during the AsA 2022 campaign

Mélanie Ghysels, Georges Durry, Nadir Amarouche, Dale Hurst, Emrys Hall, Kensy Xiong, Jean-Charles Dupont, Jean-Christophe Samake, Fabien Frérot, Raghed Bejjani, and Emmanuel Damien Riviere

Abstract. The mid-infrared lightweight stratospheric hygrometer, “Pico-Light H2O”, the successor of Pico-SDLA H2O, is presented and its performances are evaluated during the AsA 2022 balloon-borne intercomparison campaign conducted at the CNES Aire-sur-l'Adour (AsA) balloon launch facility and the Aeroclub d'Aire-sur-l'Adour. The Pico-Light instrument has primarily been developed for sounding of the upper troposphere and stratosphere. Though, during the AsA 2022 campaign we expand the range of comparison including the lower troposphere additionally. Three different types of hygrometers and two models of radiosondes were flown, operated by the French Space Agency (CNES) and the NOAA Global Monitoring Laboratory (GML) scientific teams: Pico-Light H2O, the NOAA Frost Point Hygrometer (FPH), the micro hygrometer (in an early phase of development), M20 and iMet-4 sondes. The in situ monitoring of water vapour in the UT-LS keeps being very challenging from an instrumental point of view because of the very small amounts of water vapour to be measured in these regions of the atmosphere. Between the lapse rate tropopause (11 to 12.3 km) and 20 km, the mean relative difference between water vapour mixing ratio measurements by Pico-Light H2O and NOAA FPH was (4.2 ± 7.7) %, mean tropospheric difference is was (3.84 ± 23.64) %, with differences depending on the altitude range considered. In the troposphere, relative humidity over water (RH) comparisons leads to an agreement between both Pico-Light and NOAA FPH of -0.2 % on average, with excursions of about 30 % RH due to moisture variability. Expanding the comparison to meteorological sondes, the iMet-4 sondes agree well with both Pico-Light and FPH between ground and 7.5 km (within ± 3 % RH) and so does for M20 sondes, up to 13 km, which are wet biased by 3 % RH and dry biased by 20 % in case of saturation.

Mélanie Ghysels et al.

Status: open (extended)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2023-191', Anonymous Referee #1, 10 Nov 2023 reply

Mélanie Ghysels et al.

Mélanie Ghysels et al.


Total article views: 219 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
171 43 5 219 4 4
  • HTML: 171
  • PDF: 43
  • XML: 5
  • Total: 219
  • BibTeX: 4
  • EndNote: 4
Views and downloads (calculated since 10 Oct 2023)
Cumulative views and downloads (calculated since 10 Oct 2023)

Viewed (geographical distribution)

Total article views: 214 (including HTML, PDF, and XML) Thereof 214 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 06 Dec 2023
Short summary
A tunable diode laser hygrometer, “Pico-Light H2O”, is presented and its performances are evaluated during the AsA 2022 balloon-borne intercomparison campaign from Aire-sur-l'Adour (France) in September 2022. Fifteen balloons have been launched within the framework of the E.U. funded HEMERA project. Pico-Light H2O has been compared in situ with the NOAA Frost point hygrometer in the upper troposphere and stratosphere and with meteorological sondes (iMet-4 and M20) in the troposphere.