Two-year operation of the lidar1200: from fine-scale tropospheric structures to lower stratospheric water vapor detection

Hélène Vérèmes,Jean-Luc Baray,Susanne Meier,Jean-Marc Metzger,Jean-Pierre Cammas,Franck Gabarrot,Valentin Duflot,Philippe Keckhut,Ruud Dirksen,Jimmy Leclair De Bellevue,Nicolas Marquestaut,Holger Vömel,Françoise Posny,Stéphanie Evan,Guillaume Payen

doi:10.1051/epjconf/201817605015

Abstract

The 2-year lidar water vapor database (November 2013 - October 2015) of the Maïdo Observatory (Reunion Island / 21°S,55.5°E) is now processed. The performances of the lidar in providing accurate vertical structures are shown to be good. The ability to measure quantities of a few ppmv in the lower stratosphere is demonstrated (based on Cryogenic Frost point Hygrometer sonde/lidar profiles comparisons) for a 48-hour integration time period, up to 22 km (with a vertical resolution of 1.3 km).

Highlights

Since the inauguration of the Maïdo Observatory in October 2012 [1], a Raman lidar system has been monitoring, several nights a week, water vapor and temperature, from the ground up to the lower stratosphere and in the stratosphere up to the mesosphere, respectively [2].The calibration methodology of the water vapor Lidar1200 dataset is based on the detection of quasi-stationary periods of the hourly calibration coefficient derived from GNSS observations
The results of the instrumental comparisons led during the MORGANE campaign illustrate the quality of the Lidar1200 data
The threshold of the total uncertainty of 20 % is reached at 11, 13 and 16 km asl for 10, 40- and 240-min profiles, respectively [3]. Those uncertainties are representative of a mean profile for each integration time, those values should be evaluated case-by-case depending on the measurement conditions

Summary

INTRODUCTION

Since the inauguration of the Maïdo Observatory in October 2012 [1], a Raman lidar system (called “Lidar1200”) has been monitoring, several nights a week, water vapor and temperature, from the ground up to the lower stratosphere and in the stratosphere up to the mesosphere, respectively [2]. The GNSS technique has been chosen in order to improve the reliability of the calibration and the robustness of the water vapor measurement on a long-term perspective. This methodology has been successfully used in the 2013-2015 dataset [3]. The results of the instrumental comparisons led during the MORGANE campaign illustrate the quality of the Lidar1200 data. The comparison between water vapor lidar profiles and CFH sonde’s data are detailed . The analysis of the first 2 years of data of the Lidar1200, detailed in the last sections, led to the characterization of structures that could be detected on the lidar water.

Mean performances

DETECTION OF FINE-SCALE STRUCTURES IN THE TROPOSPHERE

PRELIMINARY CHARACTERIZATION OF SEASONAL VARIATIONS OF WATER VAPOR

Findings

CONCLUSIONS