Intercomparison of in situ water vapor balloon-borne measurements from Pico-SDLA H2O and FLASH-B in the tropical UTLS
- 1Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, UFR Sciences Exactes et Naturelles, Moulin de la Housse, BP 1039, 51687 Reims CEDEX 2, France
- 2LATMOS, CNRS, Université de Versailles St. Quentin, Guyancourt, France
- 3Division technique de l'Institut National des Sciences de l'Univers, Place Aristide Briand, 92195 Meudon CEDEX 1, France
- 4Instituto de Pesquisas Meteorológicas (IPMet)/ Universidad e Estadual Paulista (UNESP), CX Postal 281, 17015-970 Bauru, São Paulo, Brazil
- anow at: National Institute of Standards and Technology, Gaithersburg, MD, USA
Abstract. In this paper we compare water vapor mixing ratio measurements from two quasi-parallel flights of the Pico-SDLA H2O and FLASH-B hygrometers. The measurements were made on 10 February 2013 and 13 March 2012, respectively, in the tropics near Bauru, São Paulo state, Brazil during an intense convective period. Both flights were performed as part of a French scientific project, TRO-Pico, to study the impact of the deep-convection overshoot on the water budget. Only a few instruments that permit the frequent sounding of stratospheric water vapor can be flown within small-volume weather balloons. Technical difficulties preclude the accurate measurement of stratospheric water vapor with conventional in situ techniques. The instruments described here are simple and lightweight, which permits their low-cost deployment by non-specialists aboard a small weather balloon. We obtain mixing ratio retrievals which agree above the cold-point tropopause to within 1.9 and 0.5 % for the first and second flights, respectively. This level of agreement for balloon-borne measured stratospheric water mixing ratio constitutes one of the best agreement reported in the literature. Because both instruments show similar profiles within their combined uncertainties, we conclude that the Pico-SDLA H2O and FLASH-B data sets are mutually consistent.