scholarly journals Five blind men and the elephant: what can the NASA Aura ozone measurements tell us about stratosphere-troposphere exchange?

2012 ◽  
Vol 12 (5) ◽  
pp. 2357-2380 ◽  
Author(s):  
Q. Tang ◽  
M. J. Prather
Keyword(s):  
Lower Stratosphere ◽  
Transport Model ◽  
Model Simulation ◽  
Atmospheric Ozone ◽  
Chemistry Transport Model ◽  
Upper Troposphere ◽  
The Individual ◽  
Low Sensitivity ◽  
The University ◽  
Individual Profiles

Abstract. We examine whether the individual ozone (O3) measurements from the four Aura instruments can quantify the stratosphere-troposphere exchange (STE) flux of O3, an important term of the tropospheric O3 budget. The level 2 (L2) Aura swath data and the nearly coincident ozone sondes for the years 2005–2006 are compared with the 4-D, high-resolution (1° × 1° × 40-layer × 0.5 h) model simulation of atmospheric ozone for the same period from the University of California, Irvine chemistry transport model (CTM). The CTM becomes a transfer standard for comparing individual profiles from these five, not-quite-coincident measurements of atmospheric ozone. Even with obvious model discrepancies identified here, the CTM can readily quantify instrument-instrument biases in the tropical upper troposphere and mid-latitude lower stratosphere. In terms of STE processes, all four Aura datasets have some skill in identifying stratosphere-troposphere folds, and we find several cases where both model and measurements see evidence of high-O3 stratospheric air entering the troposphere. In many cases identified in the model, however, the individual Aura profile retrievals in the upper troposphere and lower stratosphere show too much noise, as expected from their low sensitivity and coarse vertical resolution at and below the tropopause. These model-measurement comparisons of individual profiles do provide some level of confidence in the model-derived STE O3 flux, but it will be difficult to integrate this flux from the satellite data alone.

scholarly journals Five blind men and an elephant: can NASA Aura measurements quantify the stratosphere-troposphere exchange of ozone flux?

2011 ◽  
Vol 11 (9) ◽  
pp. 26897-26941 ◽  
Author(s):  
Q. Tang ◽  
M. J. Prather
Keyword(s):  
High Resolution ◽  
Lower Stratosphere ◽  
Transport Model ◽  
University Of California ◽  
Exact Matching ◽  
Chemistry Transport Model ◽  
Upper Troposphere ◽  
The Individual ◽  
The University ◽  
Level 2

Abstract. We examine whether the instantaneous ozone (O3) measurements from the four Aura instruments can quantify the stratosphere-troposphere exchange (STE) flux of O3, an important term of the tropospheric O3 budget. Comparing the level 2 (L2) Aura swaths and ozone sondes with the coincident, high-resolution (1°×1°×40-layer×0.5 h) simulations using the University of California, Irvine chemistry transport model (CTM) for years 2005–2006, it is revealed in many cases that all four Aura datasets have some skill in catching the STE process, while missing many of them. Despite a few cases, the individual retrievals in the upper troposphere and lower stratosphere contain too much noise preventing the quantification and integration of STE flux with Aura L2 data. The CTM is applied as a transfer standard to compare with different Aura observations. The statistics of exact matching CTM-Aura comparisons identify the model's high biases in the lower stratosphere and the inconsistency amongst different instruments, such as from tropics to Northern Hemisphere mid-latitudes in July 2005 at 215 hPa and over tropics at 147 hPa for July 2005 and January 2006.

scholarly journals A chemistry-transport model simulation of middle atmospheric ozone from 1980 to 2019 using coupled chemistry GCM winds and temperatures

2007 ◽  
Vol 7 (1) ◽  
pp. 1143-1181 ◽  
Author(s):  
J. Damski ◽  
L. Thölix ◽  
L. Backman ◽  
J. Kaurola ◽  
P. Taalas ◽  
...  
Keyword(s):  
Climate Change ◽  
High Latitude ◽  
Ozone Depletion ◽  
Transport Model ◽  
Model Simulation ◽  
Atmospheric Ozone ◽  
High Latitudes ◽  
Future Period ◽  
Chemistry Transport Model ◽  
The Past

Abstract. A Global 40-year simulation from 1980 to 2019 was performed with the FinROSE chemistry-transport model based on the use of coupled chemistry GCM-data. The main focus of our analysis is on climatological-scale processes in high latitudes. The resulting trend estimates for the past period (1980–1999) agree well with observation-based trend estimates. The results for the future period (2000–2019) suggest that the extent of seasonal ozone depletion over both northern and southern high-latitudes has likely reached its maximum. Furthermore, while climate change is expected to cool the stratosphere, this cooling is unlikely to accelerate significantly high latitude ozone depletion. However, the recovery of seasonal high latitude ozone losses will not take place during the next 15 years.

scholarly journals What drives the observed variability of HCN in the troposphere and lower stratosphere?

2009 ◽  
Vol 9 (3) ◽  
pp. 10883-10912 ◽  
Author(s):  
Q. Li ◽  
P. I. Palmer ◽  
H. C. Pumphrey ◽  
P. Bernath ◽  
E. Mahieu
Keyword(s):  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Chemistry Transport Model ◽  
Upper Troposphere ◽  
Annual Variations ◽  
Surface Emission ◽  
Chemistry Experiment ◽  
Temporal Overlap

Abstract. We use the GEOS-Chem global 3-D chemistry transport model to investigate the relative importance of chemical and physical processes that determine observed variability of hydrogen cyanide (HCN) in the troposphere and lower stratosphere. Consequently, we reconcile ground-based FTIR column measurements of HCN, which show annual and semi-annual variations, with recent space-borne measurements of HCN mixing ratio in the tropical lower stratosphere, which show a large two-year variation. We find that the observed column variability over the ground-based stations is determined by a superposition of HCN from several regional burning sources, with GEOS-Chem reproducing these column data with a positive bias of 5%. GEOS-Chem reproduces the observed tropical HCN variability from the Microwave Limb Sounder and the Atmospheric Chemistry Experiment satellite instruments with a negative bias of 7%. We show the tropical biomass burning emissions explain mostly the observed HCN variations in the upper troposphere and lower stratosphere (UTLS), with the remainder due to atmospheric transport and HCN chemistry. In the mid and upper stratosphere, atmospheric dynamics progressively exerts more influences on HCN variations. The extent of temporal overlap between African and other continental burning seasons is key in establishing the apparent bienniel cycle in the UTLS. Similar analysis of other, shorter-lived trace gases have not observed the transition between annual and bienniel cycles in the UTLS probably because the signal of inter-annual variations from surface emission has vanished before arriving at the lower stratosphere (LS), due to shorter atmospheric lifetimes.

scholarly journals A chemistry-transport model simulation of middle atmospheric ozone from 1980 to 2019 using coupled chemistry GCM winds and temperatures

2007 ◽  
Vol 7 (9) ◽  
pp. 2165-2181 ◽  
Author(s):  
J. Damski ◽  
L. Thölix ◽  
L. Backman ◽  
J. Kaurola ◽  
P. Taalas ◽  
...  
Keyword(s):  
Climate Change ◽  
High Latitude ◽  
Ozone Depletion ◽  
Transport Model ◽  
Model Simulation ◽  
Atmospheric Ozone ◽  
High Latitudes ◽  
Future Period ◽  
Chemistry Transport Model ◽  
The Past

Abstract. A global 40-year simulation from 1980 to 2019 was performed with the FinROSE chemistry-transport model based on the use of coupled chemistry GCM-data. The main focus of our analysis is on climatological-scale processes in high latitudes. The resulting trend estimates for the past period (1980–1999) agree well with observation-based trend estimates. The results for the future period (2000–2019) suggest that the extent of seasonal ozone depletion over both northern and southern high-latitudes has likely reached its maximum. Furthermore, while climate change is expected to cool the stratosphere, this cooling is unlikely to accelerate significantly high latitude ozone depletion. However, the recovery of seasonal high latitude ozone losses will not take place during the next 15 years.

scholarly journals Evaluation of near-tropopause ozone distributions in the Global Modeling Initiative combined stratosphere/troposphere model with ozonesonde data

2008 ◽  
Vol 8 (1) ◽  
pp. 1589-1634 ◽  
Author(s):  
D. B. Considine ◽  
J. A. Logan ◽  
M. A. Olsen
Keyword(s):  
Annual Cycle ◽  
Transport Model ◽  
Model Simulation ◽  
Atmospheric Composition ◽  
Vertical Resolution ◽  
Residual Circulation ◽  
Vertical Diffusion ◽  
Global Modeling ◽  
Upper Troposphere ◽  
The Tropics

Abstract. The NASA Global Modeling Initiative has developed a combined stratosphere/troposphere chemistry and transport model which fully represents the processes governing atmospheric composition near the tropopause. We evaluate model ozone distributions near the tropopause, using two high vertical resolution monthly mean ozone profile climatologies constructed with ozonesonde data, one by averaging on pressure levels and the other relative to the thermal tropopause. Model ozone is high-biased at the SH tropical and NH midlatitude tropopause by ~45% in a 4° latitude × 5° longitude model simulation. Increasing the resolution to 2°×2.5&amp;deg increases the NH tropopause high bias to ~60%, but decreases the tropical tropopause bias to ~30%, an effect of a better-resolved residual circulation. The tropopause ozone biases appear not to be due to an overly vigorous residual circulation or excessive stratosphere/troposphere exchange, but are more likely due to insufficient vertical resolution or excessive vertical diffusion near the tropopause. In the upper troposphere and lower stratosphere, model/measurement intercomparisons are strongly affected by the averaging technique. NH and tropical mean model lower stratospheric biases are <20%. In the upper troposphere, the 2°×2.5&amp;deg simulation exhibits mean high biases of ~20% and~35% during April in the tropics and NH midlatitudes, respectively, compared to the pressure-averaged climatology. However, relative-to-tropopause averaging produces upper troposphere high biases of ~30% and 70% in the tropics and NH midlatitudes. This is because relative-to-tropopause averaging better preserves large cross-tropopause O3 gradients, which are seen in the daily sonde data, but not in daily model profiles. The relative annual cycle of ozone near the tropopause is reproduced very well in the model Northern Hemisphere midlatitudes. In the tropics, the model amplitude of the near-tropopause annual cycle is weak. This is likely due to the annual amplitude of mean vertical upwelling near the tropopause, which analysis suggests is ~30% weaker than in the real atmosphere.

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

2009 ◽  
Vol 9 (5) ◽  
pp. 18511-18543 ◽  
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 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.

scholarly journals Evaluation of water vapour assimilation in the tropical upper troposphere and lower stratosphere by a chemical transport model

2016 ◽  
Vol 9 (9) ◽  
pp. 4355-4373 ◽  
Author(s):  
Swagata Payra ◽  
Philippe Ricaud ◽  
Rachid Abida ◽  
Laaziz El Amraoui ◽  
Jean-Luc Attié ◽  
...  
Keyword(s):  
Water Vapour ◽  
Lower Stratosphere ◽  
Transport Model ◽  
Michelson Interferometer ◽  
Model Space ◽  
Global Scale ◽  
Chemical Transport Model ◽  
Data Set ◽  
Upper Troposphere ◽  
Sensitivity Studies

Abstract. The present analysis deals with one of the most debated aspects of the studies on the upper troposphere/lower stratosphere (UTLS), namely the budget of water vapour (H2O) at the tropical tropopause. Within the French project “Multiscale water budget in the upper troposphere and lower stratosphere in the TROpics” (TRO-pico), a global-scale analysis has been set up based on space-borne observations, models and assimilation techniques. The MOCAGE-VALENTINA assimilation tool has been used to assimilate the Aura Microwave Limb Sounder (MLS) version 3.3 H2O measurements within the 316–5 hPa range from August 2011 to March 2013 with an assimilation window of 1 h. Diagnostics based on observations minus analysis and forecast are developed to assess the quality of the assimilated H2O fields. Comparison with an independent source of H2O measurements in the UTLS based on the space-borne Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) observations and with meteorological ARPEGE analyses is also shown. Sensitivity studies of the analysed fields have been performed by (1) considering periods when no MLS measurements are available and (2) using H2O data from another MLS version (4.2). The studies have been performed within three different spaces in time and space coincidences with MLS (hereafter referred to as MLS space) and MIPAS (MIPAS space) observations and with the model (model space) outputs and at three different levels: 121 hPa (upper troposphere), 100 hPa (tropopause) and 68 hPa (lower stratosphere) in January and February 2012. In the MLS space, the analyses behave consistently with the MLS observations from the upper troposphere to the lower stratosphere. In the model space, the analyses are wetter than the reference atmosphere as represented by ARPEGE and MLS in the upper troposphere (121 hPa) and around the tropopause (100 hPa), but are consistent with MLS and MIPAS in the lower stratosphere (68 hPa). In the MIPAS space, the sensitivity and the vertical resolution of the MIPAS data set at 121 and 100 hPa prevent assessment of the behaviour of the analyses at 121 and 100 hPa, particularly over intense convective areas as the South American, the African and the Maritime continents but, in the lower stratosphere (68 hPa), the analyses are very consistent with MIPAS. Sensitivity studies show the improvement on the H2O analyses in the tropical UTLS when assimilating space-borne measurements of better quality, particularly over the convective areas.

scholarly journals Quantifying pollution transport from the Asian monsoon anticyclone into the lower stratosphere

2017 ◽  
Vol 17 (11) ◽  
pp. 7055-7066 ◽  
Author(s):  
Felix Ploeger ◽  
Paul Konopka ◽  
Kaley Walker ◽  
Martin Riese
Keyword(s):  
Asian Monsoon ◽  
Lower Stratosphere ◽  
Transport Model ◽  
Monsoon Circulation ◽  
Pollution Transport ◽  
Chemistry Transport Model ◽  
Transport Pathways ◽  
Air Mass ◽  
Mass Fractions ◽  
The Tropics

Abstract. Pollution transport from the surface to the stratosphere within the Asian monsoon circulation may cause harmful effects on stratospheric chemistry and climate. Here, we investigate air mass transport from the monsoon anticyclone into the stratosphere using a Lagrangian chemistry transport model. We show how two main transport pathways from the anticyclone emerge: (i) into the tropical stratosphere (tropical pipe), and (ii) into the Northern Hemisphere (NH) extratropical lower stratosphere. Maximum anticyclone air mass fractions reach around 5 % in the tropical pipe and 15 % in the extratropical lowermost stratosphere over the course of a year. The anticyclone air mass fraction correlates well with satellite hydrogen cyanide (HCN) and carbon monoxide (CO) observations, confirming that pollution is transported deep into the tropical stratosphere from the Asian monsoon anticyclone. Cross-tropopause transport occurs in a vertical chimney, but with the pollutants transported quasi-horizontally along isentropes above the tropopause into the tropics and NH.

scholarly journals Quantifying pollution transport from the Asian monsoon anticyclone into the lower stratosphere

2017 ◽  
Author(s):  
Felix Ploeger ◽  
Paul Konopka ◽  
Kaley Walker ◽  
Martin Riese
Keyword(s):  
Asian Monsoon ◽  
Lower Stratosphere ◽  
Transport Model ◽  
Monsoon Circulation ◽  
Pollution Transport ◽  
Chemistry Transport Model ◽  
Transport Pathways ◽  
Air Mass ◽  
Mass Fractions ◽  
The Tropics

Abstract. Pollution transport from the surface to the stratosphere within the Asian monsoon circulation may cause harmful effects on stratospheric chemistry and climate. Here, we investigate air mass transport from the monsoon anticyclone into the stratosphere using a Lagrangian chemistry transport model. We show how two main transport pathways from the anticyclone emerge: (i) into the tropical stratosphere (tropical pipe), and (ii) into the Northern hemisphere (NH) extra-tropical lower stratosphere. Maximum anticyclone air mass fractions reach around 5 % in the tropical pipe and 15 % in the extra-tropical lowermost stratosphere over the course of a year. The anticyclone air mass fraction correlates well with satellite hydrogen cyanide (HCN) and carbon monoxide (CO) observations, corroborating that pollution is transported deep into the tropical stratosphere from the Asian monsoon anticyclone. Cross-tropopause transport occurs in a vertical chimney, but with the emissions transported quasi-horizontally along isentropes above the tropopause into the tropics and NH.

scholarly journals CHIMERE-2017: from urban to hemispheric chemistry-transport modeling

2017 ◽  
Vol 10 (6) ◽  
pp. 2397-2423 ◽  
Author(s):  
Sylvain Mailler ◽  
Laurent Menut ◽  
Dmitry Khvorostyanov ◽  
Myrto Valari ◽  
Florian Couvidat ◽  
...  
Keyword(s):  
Transport Model ◽  
Model Simulation ◽  
Point Of View ◽  
Atmospheric Composition ◽  
Test Case ◽  
Polar Regions ◽  
Chemistry Transport Model ◽  
Computational Point ◽  
Improve Model ◽  
Code Complexity

Abstract. CHIMERE is a chemistry-transport model designed for regional atmospheric composition. It can be used at a variety of scales from local to continental domains. However, due to the model design and its historical use as a regional model, major limitations had remained, hampering its use at hemispheric scale, due to the coordinate system used for transport as well as to missing processes that are important in regions outside Europe. Most of these limitations have been removed in the CHIMERE-2017 version, allowing its use in any region of the world and at any scale, from the scale of a single urban area up to hemispheric scale, with or without polar regions included. Other important improvements have been made in the treatment of the physical processes affecting aerosols and the emissions of mineral dust. From a computational point of view, the parallelization strategy of the model has also been updated in order to improve model numerical performance and reduce the code complexity. The present article describes all these changes. Statistical scores for a model simulation over continental Europe are presented, and a simulation of the circumpolar transport of volcanic ash plume from the Puyehue volcanic eruption in June 2011 in Chile provides a test case for the new model version at hemispheric scale.

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