Author details
Author M.P. Chipperfield |
Available document(s)


![]()
![]()
Impact of deep convection and dehydration on bromine loading in the upper troposphere and lower stratosphere
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Aschmann J.; Sinnhuber B.-M.; Chipperfield M.P.; et al. - Copernicus GmbH, 2011Stratospheric bromine loading due to very short-lived substances is investigated with a three-dimensional chemical transport model over a period of 21 years using meteorological input data from the European Centre for Medium-Range Weather Forecasts ERA-Interim reanalysis from 1989 to the end of 2009. Within this framework we analyze the impact of dehydration and deep convection on the amount of stratospheric bromine using an idealized and a detailed full chemistry approach. We model the two most important brominated short-lived substances, bromoform (CHBr3) and dibromomethane (CH2Br2), assumin ...
[article]Impact of deep convection and dehydration on bromine loading in the upper troposphere and lower stratosphere
![]()
![]()
Available online: http://dx.doi.org/10.5194/acp-11-2671-2011
J. Aschmann ; B.-M. Sinnhuber ; M.P. Chipperfield ; R. Hossaini
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2671-2687Stratospheric bromine loading due to very short-lived substances is investigated with a three-dimensional chemical transport model over a period of 21 years using meteorological input data from the European Centre for Medium-Range Weather Forecasts ERA-Interim reanalysis from 1989 to the end of 2009. Within this framework we analyze the impact of dehydration and deep convection on the amount of stratospheric bromine using an idealized and a detailed full chemistry approach. We model the two most important brominated short-lived substances, bromoform (CHBr3) and dibromomethane (CH2Br2), assuming a uniform convective detrainment mixing ratio of 1 part per trillion by volume (pptv) for both species. The contribution of very short-lived substances to stratospheric bromine varies drastically with the applied dehydration mechanism and the associated scavenging of soluble species ranging from 3.4 pptv in the idealized setup up to 5 pptv using the full chemistry scheme. In the latter case virtually the entire amount of bromine originating from very short-lived source gases is able to reach the stratosphere thus rendering the impact of dehydration and scavenging on inorganic bromine in the tropopause insignificant. Furthermore, our long-term calculations show that the mixing ratios of very short-lived substances are strongly correlated to convective activity, i.e. intensified convection leads to higher amounts of very short-lived substances in the upper troposphere/lower stratosphere especially under extreme conditions like El Niño seasons. However, this does not apply to the inorganic brominated product gases whose concentrations are anti-correlated to convective activity mainly due to convective dilution and possible scavenging, depending on the applied approach.
Language(s): English
Format: Digital (Free)Tags: Environment and landscape ; Air pollution ; Research ; Stratosphere ; Troposphere ; Region VI - Europe
Add tag
[article]No review, please log in to add yours !
![]()
![]()
Representation of tropical deep convection in atmospheric models – Part 1: Meteorology and comparison with satellite observations
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Russo M.R.; Marécal V.; Hoyle C.R.; et al. - Copernicus GmbH, 2011Fast convective transport in the tropics can efficiently redistribute water vapour and pollutants up to the upper troposphere. In this study we compare tropical convection characteristics for the year 2005 in a range of atmospheric models, including numerical weather prediction (NWP) models, chemistry transport models (CTMs), and chemistry-climate models (CCMs). The model runs have been performed within the framework of the SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere) project. The characteristics of tropical convection, such as seasonal c ...
[article]Representation of tropical deep convection in atmospheric models – Part 1: Meteorology and comparison with satellite observations
![]()
![]()
Available online: http://dx.doi.org/10.5194/acp-11-2765-2011
M.R. Russo ; V. Marécal ; C.R. Hoyle ; J. Arteta ; C. Chemel ; M.P. Chipperfield ; O. Dessens ; W. Feng ; J.S. Hosking ; P.J. Telford ; O. Wild ; X. Yang ; J.A. Pyle
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2765-2786Fast convective transport in the tropics can efficiently redistribute water vapour and pollutants up to the upper troposphere. In this study we compare tropical convection characteristics for the year 2005 in a range of atmospheric models, including numerical weather prediction (NWP) models, chemistry transport models (CTMs), and chemistry-climate models (CCMs). The model runs have been performed within the framework of the SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere) project. The characteristics of tropical convection, such as seasonal cycle, land/sea contrast and vertical extent, are analysed using satellite observations as a benchmark for model simulations. The observational datasets used in this work comprise precipitation rates, outgoing longwave radiation, cloud-top pressure, and water vapour from a number of independent sources, including ERA-Interim analyses. Most models are generally able to reproduce the seasonal cycle and strength of precipitation for continental regions but show larger discrepancies with observations for the Maritime Continent region. The frequency distribution of high clouds from models and observations is calculated using highly temporally-resolved (up to 3-hourly) cloud top data. The percentage of clouds above 15 km varies significantly between the models. Vertical profiles of water vapour in the upper troposphere-lower stratosphere (UTLS) show large differences between the models which can only be partly attributed to temperature differences. If a convective plume reaches above the level of zero net radiative heating, which is estimated to be ~15 km in the tropics, the air detrained from it can be transported upwards by radiative heating into the lower stratosphere. In this context, we discuss the role of tropical convection as a precursor for the transport of short-lived species into the lower stratosphere.
Language(s): English
Format: Digital (Free)Tags: Atmospheric circulation ; Chemical model of climate ; Modelling ; Observations ; Numerical weather prediction ; Research ; Satellite
Add tag
[article]No review, please log in to add yours !