Model calculations on the structure of planetary waves in the upper troposphere and lower stratosphere as a function of the wind field in the upper stratosphere

Abstract. The transport of very short-lived substances into the tropical upper troposphere and lower stratosphere is investigated by a three-dimensional chemical transport model using archived convective updraft mass fluxes (or detrainment rates) from the European Centre for Medium-Range Weather Forecast's ERA-Interim reanalysis. Large-scale vertical velocities are calculated from diabatic heating rates. With this approach we explicitly model the large scale subsidence in the tropical troposphere with convection taking place in fast and isolated updraft events. The model calculations agree generally well with observations of bromoform and methyl iodide from aircraft campaigns and with ozone and water vapor from sonde and satellite observations. Using a simplified treatment of dehydration and bromine product gas washout we give a range of 1.6 to 3 ppt for the contribution of bromoform to stratospheric bromine, assuming a uniform source in the boundary layer of 1 ppt. We show that the most effective region for VSLS transport into the stratosphere is the West Pacific, accounting for about 55% of the bromine from bromoform transported into the stratosphere under the supposition of a uniformly distributed source.

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Transport of short-lived halocarbons to the stratosphere over the Pacific Ocean

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-1163-2020 ◽

2020 ◽

Vol 20 (2) ◽

pp. 1163-1181

Author(s):

Michal T. Filus ◽

Elliot L. Atlas ◽

Maria A. Navarro ◽

Elena Meneguz ◽

David Thomson ◽

...

Keyword(s):

Boundary Layer ◽

Lower Stratosphere ◽

Atmospheric Transport ◽

Convective Transport ◽

Transport Processes ◽

Lagrangian Model ◽

Convection Scheme ◽

Model Calculations ◽

Upper Troposphere ◽

Tropical Troposphere

Abstract. The effectiveness of transport of short-lived halocarbons to the upper troposphere and lower stratosphere remains an important uncertainty in quantifying the supply of ozone-depleting substances to the stratosphere. In early 2014, a major field campaign in Guam in the western Pacific, involving UK and US research aircraft, sampled the tropical troposphere and lower stratosphere. The resulting measurements of CH3I, CHBr3 and CH2Br2 are compared here with calculations from a Lagrangian model. This methodology benefits from an updated convection scheme that improves simulation of the effect of deep convective motions on particle distribution within the tropical troposphere. We find that the observed CH3I, CHBr3 and CH2Br2 mixing ratios in the tropical tropopause layer (TTL) are consistent with those in the boundary layer when the new convection scheme is used to account for convective transport. More specifically, comparisons between modelled estimates and observations of short-lived CH3I indicate that the updated convection scheme is realistic up to the lower TTL but is less good at reproducing the small number of extreme convective events in the upper TTL. This study consolidates our understanding of the transport of short-lived halocarbons to the upper troposphere and lower stratosphere by using improved model calculations to confirm consistency between observations in the boundary layer, observations in the TTL and atmospheric transport processes. Our results support recent estimates of the contribution of short-lived bromocarbons to the stratospheric bromine budget.

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In situ detection of electrified aerosols in the upper troposphere and in the stratosphere

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-7061-2013 ◽

2013 ◽

Vol 13 (3) ◽

pp. 7061-7079 ◽

Cited By ~ 2

Author(s):

J.-B. Renard ◽

S. N. Tripathi ◽

M. Michael ◽

A. Rawal ◽

G. Berthet ◽

...

Keyword(s):

Lower Stratosphere ◽

Lower Troposphere ◽

Stratospheric Aerosol ◽

Balloon Flight ◽

Model Calculations ◽

Upper Troposphere ◽

Charged Aerosols ◽

In Situ Detection ◽

Aerosol Counter

Abstract. Electrified aerosols have been observed in the lower troposphere and in the mesosphere, but have never been detected in the stratosphere and upper troposphere. We present measurements of aerosols during a balloon flight to an altitude of ~24 km. The measurements were performed with an improved version of the STAC aerosol counter dedicated to the search for charged aerosols. It is found that most of the aerosols are charged in the upper troposphere for altitudes below 10 km and in the stratosphere for altitudes above 20 km. On the contrary, the aerosols seem to be uncharged between 10 km and 20 km. Model calculations are used to quantify the electrification of the aerosols with a stratospheric aerosol-ion model. The percentages of charged aerosols obtained with model calculations are in excellent agreement with the observations below 10 km and above 20 km. On the other hand, the model cannot reproduce the absence of detected electrification in the lower stratosphere, such that a distinct unknown process in this altitude range inhibits electrification. The presence of sporadic transient layers of electrified aerosol in the upper troposphere and in the stratosphere could have significant implications for sprite formation.

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In situ detection of electrified aerosols in the upper troposphere and stratosphere

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-11187-2013 ◽

2013 ◽

Vol 13 (22) ◽

pp. 11187-11194 ◽

Cited By ~ 6

Author(s):

J.-B. Renard ◽

S. N. Tripathi ◽

M. Michael ◽

A. Rawal ◽

G. Berthet ◽

...

Keyword(s):

Lower Stratosphere ◽

Lower Troposphere ◽

Stratospheric Aerosol ◽

Model Calculations ◽

Upper Troposphere ◽

Tropospheric Aerosol ◽

Charged Aerosols ◽

In Situ Detection ◽

Aerosol Counter

Abstract. Electrified aerosols have been observed in the lower troposphere and in the mesosphere, but have never been detected in the stratosphere and upper troposphere. We present measurements of aerosols obtained during a balloon flight to an altitude of ~ 24 km. The measurements were performed with an improved version of the Stratospheric and Tropospheric Aerosol Counter (STAC) aerosol counter dedicated to the search for charged aerosols. It is found that most of the aerosols are charged in the upper troposphere for altitudes below 10 km and in the stratosphere for altitudes above 20 km. Conversely, the aerosols seem to be uncharged between 10 km and 20 km. Model calculations are used to quantify the electrification of the aerosols with a stratospheric aerosol-ion model. The percentages of charged aerosols obtained with model calculations are in excellent agreement with the observations below 10 km and above 20 km. However, the model cannot reproduce the absence of electrification found in the lower stratosphere, as the processes leading to neutralisation in this altitude range are unknown. The presence of sporadic transient layers of electrified aerosol in the upper troposphere and in the stratosphere could have significant implications for sprite formation.

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Transport of short-lived halocarbons to the stratosphere over the Pacific Ocean

10.5194/acp-2018-640 ◽

2018 ◽

Author(s):

Michal T. Filus ◽

Elliot L. Atlas ◽

Maria A. Navarro ◽

Elena Meneguz ◽

David Thomson ◽

...

Keyword(s):

Boundary Layer ◽

Lower Stratosphere ◽

Atmospheric Transport ◽

Convective Transport ◽

Transport Processes ◽

Lagrangian Model ◽

Convection Scheme ◽

Model Calculations ◽

Upper Troposphere ◽

Tropical Troposphere

Abstract. The effectiveness of transport of short-lived halocarbons to the upper troposphere and lower stratosphere remains an important unknown in quantifying the supply of ozone-depleting substances to the stratosphere. In early 2014, a major field campaign in Guam in the West Pacific, involving UK and US research aircraft, sampled the tropical troposphere and lower stratosphere. The resulting measurements of CH3I, CHBr3 and CH2Br2 are compared here with calculations from a Lagrangian model. This methodology benefits from an updated convection scheme which improves simulation of the effect of deep convective motions on particle distribution within the tropical troposphere. We find that the observed CH3I, CHBr3 and CH2Br2 mixing ratios in the Tropical Tropopause Layer (TTL) are consistent with those in the boundary layer when the new convection scheme is used to account for convective transport. Particularly, comparisons between modelled estimates and observations of shortest-lived CH3I indicates that the NAME convection scheme is realistic up to the lower TTL but less good at reproducing the small number of extreme convective events in the upper TTL. This study consolidates our understanding of the transport of short-lived halocarbons to the upper troposphere and lower stratosphere by using improved model calculations to confirm consistency between observations in the boundary layer, observations in the TTL, and atmospheric transport processes. Our results support recent estimates of the contribution of short-lived bromocarbons to the stratospheric bromine budget.

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Modeling the transport of very short-lived substances into the tropical upper troposphere and lower stratosphere

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-9237-2009 ◽

2009 ◽

Vol 9 (23) ◽

pp. 9237-9247 ◽

Cited By ~ 104

Author(s):

J. Aschmann ◽

B.-M. Sinnhuber ◽

E. L. Atlas ◽

S. M. Schauffler

Keyword(s):

Large Scale ◽

Lower Stratosphere ◽

Transport Model ◽

Three Dimensional ◽

Chemical Transport Model ◽

Heating Rates ◽

Model Calculations ◽

Upper Troposphere ◽

Mass Fluxes ◽

Tropical Upper Troposphere

Abstract. The transport of very short-lived substances into the tropical upper troposphere and lower stratosphere is investigated by a three-dimensional chemical transport model using archived convective updraft mass fluxes (or detrainment rates) from the European Centre for Medium-Range Weather Forecast's ERA-Interim reanalysis. Large-scale vertical velocities are calculated from diabatic heating rates. With this approach we explicitly model the large scale subsidence in the tropical troposphere with convection taking place in fast and isolated updraft events. The model calculations agree generally well with observations of bromoform and methyl iodide from aircraft campaigns and with ozone and water vapor from sonde and satellite observations. Using a simplified treatment of dehydration and bromine product gas washout we give a range of 1.6 to 3 ppt for the contribution of bromoform to stratospheric bromine, assuming a uniform mixing ratio in the boundary layer of 1 ppt. We show that the most effective region for VSLS transport into the stratosphere is the West Pacific, accounting for about 55% of the bromine from bromoform transported into the stratosphere under the supposition of a uniformly distributed source.

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Measurements of the upper troposphere and lower stratosphere during tropical cyclones using the GPS radio occultation technique

Advances in Space Research ◽

10.1016/j.asr.2010.05.031 ◽

2011 ◽

Vol 47 (2) ◽

pp. 348-355 ◽

Cited By ~ 7

Author(s):

Riccardo Biondi ◽

Torsten Neubert ◽

Stig Syndergaard ◽

Johannes Nielsen

Keyword(s):

Tropical Cyclones ◽

Radio Occultation ◽

Lower Stratosphere ◽

Upper Troposphere ◽

Gps Radio Occultation

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A Case Study of Mass Transport during the East-West Oscillation of the Asian Summer Monsoon Anticyclone

Advances in Meteorology ◽

10.1155/2017/5174025 ◽

2017 ◽

Vol 2017 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Jiali Luo ◽

Jiayao Song ◽

Hongying Tian ◽

Lei Liu ◽

Xinlei Liang

Keyword(s):

Lower Stratosphere ◽

Asian Summer Monsoon ◽

Chemical Transport ◽

Upward Motion ◽

High Concentration ◽

Upper Troposphere ◽

Asian Summer ◽

Mode Tm ◽

East West

We use ERA-Interim reanalysis, MLS observations, and a trajectory model to examine the chemical transport and tracers distribution in the Upper Troposphere and Lower Stratosphere (UTLS) associated with an east-west oscillation case of the anticyclone in 2016. The results show that the spatial distribution of water vapor (H2O) was more consistent with the location of the anticyclone than carbon monoxide (CO) at 100 hPa, and an independent relative high concentration center was only found in H2O field. At 215 hPa, although the anticyclone center also migrated from the Tibetan Mode (TM) to the Iranian Mode (IM), the relative high concentration centers of both tracers were always colocated with regions where upward motion was strong in the UTLS. When the anticyclone migrated from the TM, air within the anticyclone over Tibetan Plateau may transport both westward and eastward but was always within the UTLS. The relative high concentration of tropospheric tracers within the anticyclone in the IM was from the east and transported by the westward propagation of the anticyclone rather than being lifted from surface directly. Air within the relative high geopotential height centers over Western Pacific was partly from the main anticyclone and partly from lower levels.

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