Jimmy Leclair de Bellevue

Centre National de la Recherche Scientifique

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Jean‐Luc Baray

Observatoire de Physique du Globe de Clermont-Ferrand

Jean‐Pierre Cammas

Observatoire des Sciences de l'Univers de la Réunion

Françoise Posny

Laboratoire de l'Atmosphère et des Cyclones

Jean‐Marc Metzger

Observatoire des Sciences de l'Univers de la Réunion

Franck Gabarrot

Observatoire des Sciences de l'Univers de la Réunion

Philippe Keckhut

Sorbonne Université

Alain Hauchecorne

Centre National de la Recherche Scientifique

Valentin Duflot

Norwegian Institute for Air Research

Hélène Vérèmes

Laboratoire de l'Atmosphère et des Cyclones

R. D. Diab

University of KwaZulu-Natal

Cooperative Institutions

Centre National de la Recherche Scientifique

Météo-France

Observatoire des Sciences de l'Univers de la Réunion

Laboratoire de l'Atmosphère et des Cyclones

Sorbonne Université

Université de Versailles Saint-Quentin-en-Yvelines

Institut Pierre-Simon Laplace

Université Paris Cité

Laboratoire atmosphères, milieux, observations spatiales

Écologie Marine Tropicale des Océans Pacifique et Indien

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Maïdo observatory: a new high-altitude station facility at Reunion Island (21° S, 55° E) for long-term atmospheric remote sensing and in situ measurements

Atmospheric measurement techniques (2013)

Jean‐Luc Baray Yann Courcoux Philippe Keckhut Thierry Portafaix Pierre Tulet

Abstract. Since the nineties, atmospheric measurement systems have been deployed at Reunion Island, mainly for monitoring the atmospheric composition in the framework of NDSC/NDACC (Network for the Detection of Stratospheric Change/Network for the Detection of Atmospheric Composition Change). The location of Reunion Island presents a great interest because there are very few multi-instrumented stations in the tropics and particularly in the southern hemisphere. In 2012, a new observatory was commissioned in Maïdo at 2200 m above sea level: it hosts various instruments for atmospheric measurements, including lidar systems, spectro-radiometers and in situ gas and aerosol measurements. This new high-altitude Maïdo station provides an opportunity: 1. to improve the performance of the optical instruments above the marine boundary layer, and to open new perspectives on upper troposphere and lower stratosphere studies; 2. to develop in situ measurements of the atmospheric composition for climate change surveys, in a reference site in the tropical/subtropical region of the southern hemisphere; 3. to offer trans-national access to host experiments or measurement campaigns for focused process studies.

10.5194/amt-6-2865-2013

Cite

Citations (118)

Characterization of tropical cyclones in the South Indian Ocean by using GNSS observations

EGUGA (2017)

Rita Nogherotto Riccardo Biondi Jimmy Leclair de Bellevue Hugues Brenot

Source

Cite

Citations (1)

Role of convective transport on tropospheric ozone chemistry revealed by aircraft observations during the wet season of the AMMA campaign

G. Ancellet Jimmy Leclair de Bellevue C. Mari P. Nédélec Alexandre Kukui

Abstract. During the wet season of the African Monsoon Multidisciplinary Analyses (AMMA) campaign, airborne measurements of several chemical species were made onboard the French Falcon-20 (FF20) aircraft. The scientific flights were planned in order to document, on one hand the regional distribution of trace gas species related to the oxidizing capacity of the troposphere, and on the other hand their spatial variability in the outflow of mesoscale convective systems (MCSs). The main objectives of this paper are the analysis of the main transport processes responsible for the observed variability, and the discussion of differences and similarities related to the convective transport by 4 different MCSs. This work is needed before using this data set for future studies of the convective transport of chemical species or for modeling work in the frame of the AMMA project. Regarding the regional distribution, five air masses types have been identified using the Lagrangian particle dispersion model FLEXPART, and by considering relationship between the measured trace gas concentrations (O3, CO, NOx, H2O, and hydroperoxides). This paper specifically discusses the advantage of hydroperoxide measurements in order to document the impact of recent or aged convection. The highest values of O3 are found to be related to transport from the subtropical tropopause region into the mid-troposphere at latitudes as low as 10° N. The lowest ozone values have been always explained by recent uplifting from the monsoon layer where O3 is photochemically destroyed. Regarding the analysis of the MCS outflow, the CO and H2O2 enhancements are related to the age and the southernmost position of the MCS. The analysis of the long range transport of the air masses where convection occurred, shows a connection with the Persian Gulf emissions for the largest CO concentrations in MCS outflow. However for our observations, Lagrangian particle dispersion modelling shows that this possible source is always modified by the convective transport of CO from the African lower troposphere when the air masses encounter a convective system at latitudes below 10° N.

Chemical Transport Model

Tropopause

Outflow

Trace gas

Tropospheric ozone

10.5194/acpd-8-15941-2008

Cite

Citations (2)

Simulations of stratospheric to tropospheric transport during the tropical cyclone Marlene event

Atmospheric Environment (2007)

Jimmy Leclair de Bellevue Jean‐Luc Baray S. Baldy G. Ancellet R. D. Diab

Tropospheric ozone

Atlantic hurricane

10.1016/j.atmosenv.2007.04.040

Cite

Citations (43)

Temperature variability and trend estimates at tropopause and UT-LS over a subtropical site: Reunion (20.8° S, 55.5° E)

Nelson Bègue Hassan Benchérif Venkataraman Sivakumar Guillaume Kirgis Nahoudha Mzé

Abstract. This paper mainly focuses on the trends and variability of the tropopause and UT-LS temperature using radiosonde observations carried out over 16 years (January 1993 to December 2008) from a southern subtropical site, Reunion Island (20.8° S, 55.5° E), using a linear-regression fitting model. Two kinds of tropopause definitions, namely, cold point tropopause (CPT) and lapse rate tropopause (LRT) are used. In the purpose to characterize and quantify the relationship between the regional oceanic forcing and temperature at tropopause and UT-LS, we take into account the Indian Ocean Dipole (IOD) for the estimation of temperature trends. Results show that the main component is the Annual Oscillation (AO), particularly at tropopause (CPT, LRT) and in the lower stratosphere (LS) where more than 26% of the variability of temperature can be explained by AO. As a result, the influence of IOD on the variability of the temperature is at highest ratio at CPT and LS, with respectively 12.3% and 13.1%. The results show a low correlation between IOD and the temperature anomalies at tropopause (LRT, CPT) and UT-LS, in the range of 0.08–0.15, with the maximum of correlation at CPT (0.15). In addition, trend estimates at CPT and in the LS suggests that the IOD forcing contributes enhancing the rate of cooling of about 0.1 K per decade. Indeed a trend analysis reveals a cooling of about 0.90±0.40 K per decade at LS and a cooling trend of about 0.36±0.48 K per decade at CPT. The cooling trend at LS is found to be in good agreement with the others studies. These results support the assumption that the Indian Ocean may have a slight impact on temperature variability and on temperature change at CPT and in the LS over Reunion.

Tropopause

Quasi-biennial oscillation

Forcing (mathematics)

10.5194/acpd-10-10113-2010

Cite

Citations (0)

Tropospheric ozone production related to West African city emissions during the 2006 wet season AMMA campaign

G. Ancellet E. Orlandi E. Real Kathy S. Law Hans Schlager

Abstract. During the African Monsoon Multidisciplinary Analyses (AMMA) airborne measurements of ozone, CO and nitrogen oxides by the French and German falcon aircraft took place near three cities in West Africa (Cotonou, Niamey and Ouagadougou). Significant ozone production (O3 increase of 40–50 ppbv) took place during two specific events: one near Cotonou on the coast of the Guinea Gulf, and the other near Niamey in the Sahel region. In both cases a high level of NOx (>3 ppbv) is related to the ozone production. The ozone production is mainly driven by the Lagos-Cotonou anthropogenic emissions in Cotonou. In Niamey the combined effect of advection of VOC emissions from the forest and stagnation over the city area and the poorly vegetated soils recently wetted by convected systems is needed to achieve a similar level of ozone precursors. In Ouagadougou no ozone plume is found because of the absence of a pause in the convective activity and of the larger vegetated area around the city which prevented ozone plume formation during the wet season. To discuss the ozone increase near Cotonou two different approaches have been implemented: a FLEXPART simulation to quantify the probability of transport from the SH compared to air mass stagnation over the emission area and a simulation of the BOLAM mesoscale model with two different tracers for the anthropogenic emission (RETRO inventory for 2000) and the biomass burning. The BOLAM model shows a good agreement with the meteorological observations of the aircraft and allows to identify the key influence of the anthropogenic emissions in the first 3 km while the biomass burning plume remains above this altitude. The day to day variability of the ozone and CO in Niamey and Ouagadougou is discussed using FLEXPART simulations of the air mass stagnation in the 12° N–14° N latitude band and northward advection of air masses from the vegetated areas influenced by the biogenic volatile organic compound (VOC) emissions. Both conditions need to be fulfilled to be able to detect ozone increase within the city plume. The first condition is necessary to obtain a significant increase of the NOx concentrations by combining the city emission and the soil emission. It also shows that, contrary to the Niamey conditions, the Ouagadougou air mass transport and its timing respective to the convective activity did not correspond to favourable conditions for O3 formation during the time period of the aircraft data. Finally to check the magnitude of the ozone production related to the observed CO and NOx observations, a 2-days stationary run of the CittyCAT Lagrangian model was conducted at Cotonou location. The initialisation of the chemical concentrations not measured is done by scaling to the NOx and CO concentrations observed in the polluted plume. The scaling factor is derived from the low altitude observations provided by the DF20 and the BAe-146 aircraft during the AMMA campaign. Under such conditions, the simulation show that 50 ppbv of ozone can be produced in a 2-days period.

Tropospheric ozone

Diurnal cycle

Mineral dust

10.5194/acpd-10-27135-2010

Cite

Citations (0)

Water Vapor Profiles up to the UT/LS from Raman Lidar at Reunion Island (21°S, 55°E) : Technical Description, Data Processing and Comparison with Sondes

EPJ Web of Conferences (2016)

Hélène Vérèmes Philippe Keckhut Jean‐Luc Baray Jean‐Pierre Cammas Davide Dionisi

The Maïdo high-altitude observatory located in Reunion Island (21°S, 55°E) is equipped with an innovative lidar designed to monitor the water vapor in the whole troposphere up to the lower stratosphere with a Raman system and to monitor, simultaneously, the temperature in the stratosphere and in the mesosphere based on a Rayleigh scattering technique. Several improvements have been performed on the new instrument to optimize the water vapor mixing ratio measurements thanks to the experience of the previous system. The choice of the operational configuration of the system and the calibration methodology were realized during the campaign MALICCA-1 (MAïdo LIdar Calibration CAmpaign) which provided simultaneous measurements of water vapor and ozone in April 2013. The lidar water vapor profiles are calibrated with water vapor columns obtained from a collocated GNSS receiver. By comparing CFH and Vaisala radiosondes and satellites water vapor mixing ratio profiles with the Raman lidar profiles, the performances of the lidar are shown to be good in the troposphere. With a suitable integration time period, the ability of measuring quantities of a few ppmv in the lower stratosphere is demonstrated. This Raman lidar will provide regular measurements to international networks with high vertical resolution profiles of water vapor in order to document various studies and to insure a long-term survey of the troposphere and of the lower stratosphere.

Mixing ratio

10.1051/epjconf/201611905004

Cite

Citations (0)

Signatures of stratosphere to troposphere transport near deep convective events in the southern subtropics

Journal of Geophysical Research Atmospheres (2006)

Jimmy Leclair de Bellevue Anne Réchou Jean‐Luc Baray G. Ancellet R. D. Diab

A climatology of tropospheric ozone profiles associated with tropical convection in the southwestern part of the Indian Ocean and over South Africa is presented. Then case studies of stratospheric‐tropospheric exchange are documented using radiosoundings, ozone lidar, satellite and ECMWF global model data. In three distinct cases of varying tropical convection intensity (depression and cyclone Guillaume near Reunion in February 2002 and convection near Irene in November 2000), strong interaction between convection‐induced upper level circulation, jet front systems and Rossby Wave Breaking induces stratosphere to troposphere exchanges. Stratospheric filaments in the upper troposphere evident in the ECMWF analyses are in good agreement with ozone, humidity and temperature vertical profile observations. For the Guillaume case study near Reunion, filaments and subsidence occur in both cases (depression on 15 February and cyclone on 19 February 2002). On 15 February, a moderate enhancement of ozone in the free troposphere is observed and on 19 February, a 100 ppbv ozone peak is recorded. In the Irene case study, a large upper level depression coming from the stratosphere, fed by a filament wrapped around the convective area in the Mozambican channel, induces an ozone peak of larger magnitude (170 ppbv). Secondary ozone sources (jet front system in the Atlantic and biomass burning in South America) could further amplify this ozone enhancement. The radiosounding indicates a strong ozone enhancement in the upper troposphere, without a signature of pumping from the lower layers, in contrast to the Guillaume case.

Tropopause

Tropical cyclogenesis

Atmospheric convection

10.1029/2005jd006947

Cite

Citations (27)

Maïdo observatory: a new altitude station facility at Reunion Island (21° S, 55° E) for long-term atmospheric remote sensing and in-situ measurements

Jean‐Luc Baray Yann Courcoux Philippe Keckhut Thierry Portafaix Pierre Tulet

Abstract. Since the nineties, atmospheric measurement systems have been deployed at Reunion Island, mainly for monitoring the atmospheric composition in the framework of NDSC/NDACC (Network for the Detection of Stratospheric Change/Network for the Detection of Atmospheric Composition Change). The location of Reunion Island presents a great interest because there are very few multi-instrumented stations in the tropics and particularly in the Southern Hemisphere. In 2012, a new observatory was commissioned in Maïdo at 2200 m a.s.l.: it hosts various instruments for atmospheric measurements, including LiDAR systems, spectro-radiometers and in situ gases and aerosols measurements. This new high-altitude Maïdo station allows: 1. To improve the performance of the optical instruments above the marine boundary layer, and to open new perspectives on upper troposphere and lower stratosphere studies. 2. To develop in-situ measurements of the atmospheric composition for climate change survey, in a reference site in the tropical/subtropical region of the Southern Hemisphere. 3. To offer trans-national access to host experiments or measurement campaigns for focused process studies.

Atmospheric Composition

10.5194/amtd-6-6371-2013

Cite

Citations (0)

Effects of regional-scale and convective transports on tropospheric ozone chemistry revealed by aircraft observations during the wet season of the AMMA campaign

Atmospheric chemistry and physics (2009)

G. Ancellet Jimmy Leclair de Bellevue C. Mari P. Nédélec Alexandre Kukui

Abstract. The African Monsoon Multidisciplinary Analyses (AMMA) fourth airborne campaign was conducted in July–August 2006 to study the chemical composition of the middle and upper troposphere in West Africa with the major objective to better understand the processing of chemical emissions by the West African Monsoon (WAM) and its associated regional-scale and vertical transports. In particular, the french airborne experiment was organized around two goals. The first was to characterize the impact of Mesoscale Convective Systems (MCSs) on the ozone budget in the upper troposphere and the evolution of the chemical composition of these convective plumes as they move westward toward the Atlantic Ocean. The second objective was to discriminate the impact of remote sources of pollution over West Africa, including transport from the middle east, Europe, Asia and from southern hemispheric fires. Observations of O3, CO, NOx, H2O and hydroperoxide above West Africa along repeated meridional transects were coupled with transport analysis based on the FLEXPART lagrangian model. The cross analysis of trace gas concentrations and transport pathways revealed 5 types of air masses: convective uplift of industrial and urban emissions, convective uplift of biogenic emissions, slow advection from Cotonou polluted plumes near the coast, meridional transport of upper tropospheric air from the subtropical barrier region, and meridional transport of Southern Hemisphere (SH) biomass burning emissions. O3/CO correlation plots and the correlation plots of H2O2 with a OH proxy revealed not only a control of the trace gas variability by transport processes but also significant photochemical reactivity in the mid- and upper troposphere. The study of four MCSs outflow showed contrasted chemical composition and air mass origins depending on the MCSs lifetime and latitudinal position. Favorables conditions for ozone production were found for MCSs with increased MCS lifetime (>1.5 days), which allowed for more H2O2 formation, and with trajectories crossing the 10° N latitude, which increased CO transport to the upper troposphere. The upper tropospheric concentrations sampled in the MCS outflow regions showed mixed origins including local vertical convective transport, and uplifting of air from the low troposphere over the middle-east related to the summer Asian low pressure system or from the southern hemispheric fires.

Trace gas

Chemical Transport Model

10.5194/acp-9-383-2009

Cite

Citations (46)