scholarly journals Dynamically controlled ozone decline in the tropical mid-stratosphere observed by SCIAMACHY

2019 ◽  
Vol 19 (2) ◽  
pp. 767-783 ◽  
Author(s):  
Evgenia Galytska ◽  
Alexey Rozanov ◽  
Martyn P. Chipperfield ◽  
Sandip. S. Dhomse ◽  
Mark Weber ◽  
...  
Keyword(s):  
Residence Time ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Satellite Measurements ◽  
Linear Change ◽  
Chemistry Transport Model ◽  
Negative Change ◽  
Time Period ◽  
Scanning Imaging ◽  
Odd Nitrogen

Abstract. Despite the recently reported beginning of a recovery in global stratospheric ozone (O3), an unexpected O3 decline in the tropical mid-stratosphere (around 30–35 km altitude) was observed in satellite measurements during the first decade of the 21st century. We use SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) measurements for the period 2004–2012 to confirm the significant O3 decline. The SCIAMACHY observations show that the decrease in O3 is accompanied by an increase in NO2. To reveal the causes of these observed O3 and NO2 changes, we performed simulations with the TOMCAT 3-D chemistry-transport model (CTM) using different chemical and dynamical forcings. For the 2004–2012 time period, the TOMCAT simulations reproduce the SCIAMACHY-observed O3 decrease and NO2 increase in the tropical mid-stratosphere. The simulations suggest that the positive changes in NO2 (around 7 % decade−1) are due to similar positive changes in reactive odd nitrogen (NOy), which are a result of a longer residence time of the source gas N2O and increased production via N2O + O(1D). The model simulations show a negative change of 10 % decade−1 in N2O that is most likely due to variations in the deep branch of the Brewer–Dobson Circulation (BDC). Interestingly, modelled annual mean “age of air” (AoA) does not show any significant changes in transport in the tropical mid-stratosphere during 2004–2012. However, further analysis of model results demonstrates significant seasonal variations. During the autumn months (September–October) there are positive AoA changes that imply transport slowdown and a longer residence time of N2O allowing for more conversion to NOy, which enhances O3 loss. During winter months (January–February) there are negative AoA changes, indicating faster N2O transport and less NOy production. Although the variations in AoA over a year result in a statistically insignificant linear change, non-linearities in the chemistry–transport interactions lead to a statistically significant negative N2O change.

scholarly journals Dynamically controlled ozone decline in the tropical mid-stratosphere observed by SCIAMACHY

2018 ◽  
Author(s):  
Evgenia Galytska ◽  
Alexey Rozanov ◽  
Martyn P. Chipperfield ◽  
Sandip S. Dhomse ◽  
Mark Weber ◽  
...  
Keyword(s):  
Residence Time ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Satellite Measurements ◽  
Chemistry Transport Model ◽  
Deep Branch ◽  
Negative Change ◽  
Time Period ◽  
Scanning Imaging ◽  
Odd Nitrogen

Abstract. Despite the recently reported beginning of a recovery in global stratospheric ozone (O3), an unexpected O3 decline in the tropical mid-stratosphere (around 30–35 km altitude) was observed in satellite measurements during the first decade of the 21st century. We use SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) measurements for the period 2004–2012 to confirm the significant O3 decline. The SCIAMACHY observations also show that the decrease in O3 is accompanied by an increase in NO2. To reveal the causes of these observed O3 and NO2 changes, we performed simulations with the TOMCAT 3D Chemistry-Transport Model (CTM) using different chemical and dynamical forcings. For the 2004–2012 time period, the TOMCAT simulations reproduce the SCIAMACHY-observed O3 decrease and NO2 increase in the tropical mid-stratosphere. The simulations suggest that the positive changes in NO2 (around 7 % per decade) are due to similar positive changes in reactive odd nitrogen (NOy), which are a result of a longer residence time of the source gas N2O and increased production via N2O + O(1D). The model simulations show a negative change of 10 % per decade in N2O that is most likely due to variations in the deep branch of the Brewer-Dobson Circulation (BDC). Interestingly, modelled annual mean age-of-air (AoA) does not show any significant changes in the transport in the tropical mid-stratosphere during 2004–2012. However, further analysis of model results demonstrate significant seasonal variations. During the autumn months (September–October) there are positive AoA changes, that imply transport slowdown and a longer residence time of N2O allowing larger conversion to NOy which enhances O3 loss. During winter months (January–February) there are negative AoA changes, indicating faster N2O transport and less NOy production. Although the changes in AoA cancel out when averaging over the year, non-linearities in the chemistry-transport interactions mean that the net negative N2O change remains.

scholarly journals Variability of springtime transpacific pollution transport during 2000–2006: the INTEX-B mission in the context of previous years

2010 ◽  
Vol 10 (3) ◽  
pp. 1345-1359 ◽  
Author(s):  
G. G. Pfister ◽  
L. K. Emmons ◽  
D. P. Edwards ◽  
A. Arellano ◽  
T. Campos ◽  
...  
Keyword(s):  
Transport Model ◽  
Pollution Transport ◽  
Chemistry Transport Model ◽  
Pollution Levels ◽  
Annual Variability ◽  
Source Regions ◽  
Time Period ◽  
The Pacific ◽  
The Us ◽  
Transport Experiment

Abstract. We analyze the transport of pollution across the Pacific during the NASA INTEX-B (Intercontinental Chemical Transport Experiment Part B) campaign in spring 2006 and examine how this year compares to the time period for 2000 through 2006. In addition to aircraft measurements of carbon monoxide (CO) collected during INTEX-B, we include in this study multi-year satellite retrievals of CO from the Measurements of Pollution in the Troposphere (MOPITT) instrument and simulations from the chemistry transport model MOZART-4. Model tracers are used to examine the contributions of different source regions and source types to pollution levels over the Pacific. Additional modeling studies are performed to separate the impacts of inter-annual variability in meteorology and dynamics from changes in source strength. Interannual variability in the tropospheric CO burden over the Pacific and the US as estimated from the MOPITT data range up to 7% and a somewhat smaller estimate (5%) is derived from the model. When keeping the emissions in the model constant between years, the year-to-year changes are reduced (2%), but show that in addition to changes in emissions, variable meteorological conditions also impact transpacific pollution transport. We estimate that about 1/3 of the variability in the tropospheric CO loading over the contiguous US is explained by changes in emissions and about 2/3 by changes in meteorology and transport. Biomass burning sources are found to be a larger driver for inter-annual variability in the CO loading compared to fossil and biofuel sources or photochemical CO production even though their absolute contributions are smaller. Source contribution analysis shows that the aircraft sampling during INTEX-B was fairly representative of the larger scale region, but with a slight bias towards higher influence from Asian contributions.

scholarly journals An alternative way to evaluate chemistry-transport model variability

2017 ◽  
Vol 10 (3) ◽  
pp. 1199-1208 ◽  
Author(s):  
Laurent Menut ◽  
Sylvain Mailler ◽  
Bertrand Bessagnet ◽  
Guillaume Siour ◽  
Augustin Colette ◽  
...  
Keyword(s):  
Transport Model ◽  
Model Performance ◽  
Error Statistics ◽  
Chemistry Transport Model ◽  
Temporal Correlations ◽  
Time Period ◽  
The Difference ◽  
Model Variability ◽  
Spatial Locations ◽  
Statistical Indicators

Abstract. A simple and complementary model evaluation technique for regional chemistry transport is discussed. The methodology is based on the concept that we can learn about model performance by comparing the simulation results with observational data available for time periods other than the period originally targeted. First, the statistical indicators selected in this study (spatial and temporal correlations) are computed for a given time period, using colocated observation and simulation data in time and space. Second, the same indicators are used to calculate scores for several other years while conserving the spatial locations and Julian days of the year. The difference between the results provides useful insights on the model capability to reproduce the observed day-to-day and spatial variability. In order to synthesize the large amount of results, a new indicator is proposed, designed to compare several error statistics between all the years of validation and to quantify whether the period and area being studied were well captured by the model for the correct reasons.

Validation of satellite-constrained ammonia using a CTM and ground and satellite measurements

2020 ◽  
Author(s):  
Nikolaos Evangeliou ◽  
Yves Balkanski ◽  
Sabine Eckhardt ◽  
Didier Hauglustaine ◽  
Anne Cozic ◽  
...  
Keyword(s):  
Transport Model ◽  
Relevant Literature ◽  
Volcanic Eruptions ◽  
Interpolation Algorithm ◽  
Satellite Measurements ◽  
Chemistry Transport Model ◽  
Distance Weighting ◽  
Atmospheric Sounding ◽  
Removal Processes ◽  
Inverse Distance

<p>Ammonia (NH3) has received a lot of attention nowadays due to its major implications for the population and the environment. Global sources of ammonia include wild animals, ammonia-containing water areas, traffic, sewage systems, humans, biomass burning (mainly from dung fires and domestic coal combustion), volcanic eruptions and agriculture. In the present study, we used 10 years (2008–2017) of satellite measurements of ammonia retrieved from the Infrared Atmospheric Sounding Interferometer (IASI) to calculate surface emissions. In contrast to other methods, we first used a sophisticated Inverse Distance Weighting (IDW) interpolation algorithm to define a grid of column-integrated ammonia concentrations globally. In a hypothetical box model, emissions are given as a function of the mass of ammonia in each atmospheric box (in molecules cm-3) divided by the lifetime of ammonia in the box (in seconds) based on all the potential removal processes that affect atmospheric ammonia. Instead of considering the lifetime of ammonia as a constant value, such as in the relevant literature, we used calculated gridded lifetimes from a Chemistry Transport Model (CTM). The estimated emissions were then imported in a CTM and were simulated for the same 10–year period. To verify the improvement of the calculated emissions of ammonia, we evaluated the modelled surface concentrations against ground–based measurements from different monitoring stations. The same comparison was performed for the most recent state–of–the–art emission dataset for ammonia.</p>

scholarly journals Transpacific pollution transport during INTEX-B: spring 2006 in context to previous years

2009 ◽  
Vol 9 (4) ◽  
pp. 17817-17849 ◽  
Author(s):  
G. G. Pfister ◽  
L. K. Emmons ◽  
D. P. Edwards ◽  
A. Arellano ◽  
G. Sachse ◽  
...  
Keyword(s):  
Transport Model ◽  
Pollution Transport ◽  
Chemistry Transport Model ◽  
Pollution Levels ◽  
Annual Variability ◽  
Source Regions ◽  
Time Period ◽  
The Pacific ◽  
The Us ◽  
Transport Experiment

Abstract. We analyze the transport of pollution across the Pacific during the NASA INTEX-B (Intercontinental Chemical Transport Experiment Part B) campaign in spring 2006 and examine how this year compares to the time period for 2000 through 2006. In addition to aircraft measurements of carbon monoxide (CO) collected during INTEX-B, we include in this study multi-year satellite retrievals of CO from the Measurements of Pollution in the Troposphere (MOPITT) instrument and simulations from the chemistry transport model MOZART-4. Model tracers are used to examine the contributions of different source regions and source types to pollution levels over the Pacific. Additional modeling studies are performed to separate the impacts of inter-annual variability in meteorology and dynamics from changes in source strength. Interannual variability in the tropospheric CO burden over the Pacific and the US as estimated from the MOPITT data range up to 7% and a somewhat smaller estimate (5%) is derived from the model. When keeping the emissions in the model constant between years, the year-to-year changes are reduced to (2%), but show that in addition to changes in emissions, variable meteorological conditions also impact transpacific pollution transport. We estimate that about 1/3 of the variability in the tropospheric CO loading over the contiguous US is explained by changes in emissions and about 2/3 by changes in meteorology and transport. Biomass burning sources are found to be a larger driver for inter-annual variability in the CO loading compared to fossil and biofuel sources or photochemical CO production even though their absolute contributions are smaller. Source contribution analysis shows that the aircraft sampling during INTEX-B was fairly representative of the larger scale region, but with a slight bias towards higher influence from Asian contributions.

scholarly journals Three-dimensional model evaluation of the Ozone Depletion Potentials for n-propyl bromide, trichloroethylene and perchloroethylene

2011 ◽  
Vol 11 (5) ◽  
pp. 2371-2380 ◽  
Author(s):  
D. J. Wuebbles ◽  
K. O. Patten ◽  
D. Wang ◽  
D. Youn ◽  
M. Martínez-Avilés ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Ozone Depletion ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Three Dimensional ◽  
Past Study ◽  
Three Dimensional Model ◽  
Chemistry Transport Model ◽  
Land Surfaces ◽  
Simplified Modeling

Abstract. The existing solvents trichloroethylene (TCE) and perchloroethylene (PCE) and proposed solvent n-propyl bromide (nPB) have atmospheric lifetimes from days to a few months, but contain chlorine or bromine that could affect stratospheric ozone. Several previous studies estimated the Ozone Depletion Potentials (ODPs) for various assumptions of nPB emissions location, but these studies used simplified modeling treatments. The primary purpose of this study is to reevaluate the ODP for n-propyl bromide (nPB) using a current-generation chemistry-transport model of the troposphere and stratosphere. For the first time, ODPs for TCE and PCE are also evaluated in a three-dimensional, global atmospheric chemistry-transport model. Emissions representing industrial use of each compound are incorporated on land surfaces from 30° N to 60° N. The atmospheric chemical lifetime obtained for nPB is 24.7 days, similar to past literature, but the ODP is 0.0049, lower than in our past study of nPB. The derived atmospheric lifetime for TCE is 13.0 days and for PCE is 111 days. The corresponding ODPs are 0.00037 and 0.0050, respectively.

scholarly journals Three-dimensional model evaluation of the Ozone Depletion Potentials for n-propyl bromide, trichloroethylene and perchloroethylene

2010 ◽  
Vol 10 (7) ◽  
pp. 17889-17910 ◽  
Author(s):  
D. J. Wuebbles ◽  
K. O. Patten ◽  
D. Wang ◽  
D. Youn ◽  
M. Martínez-Avilés ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Chemistry Transport Model ◽  
Atmospheric Lifetime ◽  
Land Surfaces ◽  
Simplified Modeling ◽  
First Time

Abstract. The existing solvents trichloroethylene (TCE) and perchloroethylene (PCE) and proposed solvent n-propyl bromide (nPB) have atmospheric lifetimes from days to a few months, but contain chlorine or bromine that could affect stratospheric ozone. Several previous studies estimated the Ozone Depletion Potentials (ODPs) for various assumptions for location of nPB emissions, but these studies used simplified modeling treatments. The primary purpose of this study is to reevaluate the ODP for nPB using a current-generation chemistry-transport model of the troposphere and stratosphere. For the first time, ODPs for TCE and PCE are also evaluated. Emissions representing industrial use of each compound are incorporated on land surfaces from 30° N to 60° N. The atmospheric chemical lifetime obtained for nPB is 24.7 days, similar to past literature, but the ODP is 0.0049, lower than in past studies. The derived atmospheric lifetime for TCE is 13.0 days and for PCE is 111 days. The corresponding ODPs are 0.00035 and 0.0060, respectively.

scholarly journals The influence of biogenic emissions on upper-tropospheric methanol as revealed from space

2007 ◽  
Vol 7 (3) ◽  
pp. 9183-9202 ◽  
Author(s):  
G. Dufour ◽  
S. Szopa ◽  
D. A. Hauglustaine ◽  
C. D. Boone ◽  
C. P. Rinsland ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Transport Model ◽  
State Of The Art ◽  
Tropospheric Chemistry ◽  
Biogenic Emissions ◽  
Fourier Transform Spectrometer ◽  
Satellite Measurements ◽  
Chemistry Transport Model ◽  
Organic Species ◽  
Global Space

Abstract. The distribution and budget of oxygenated organic compounds in the atmosphere and their impact on tropospheric chemistry are still poorly constrained. Near-global space-borne measurements of seasonally resolved upper tropospheric profiles of methanol by the ACE Fourier transform spectrometer provide a unique opportunity to evaluate our understanding of this important oxygenated organic species. The comparison with distributions simulated by a state-of-the-art chemistry transport model shows fair agreement during the March 2004 to August 2005 period with about 50% of the measurements reproduced by the model within 50%. However, in the northern hemisphere and during summertime, the satellite measurements reveal that the emissions from the continental biosphere lead to upper-tropospheric methanol concentrations significantly higher than expected.

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