scholarly journals Acetone in the free troposphere and lower stratosphere: Aircraft-based CIMS and GC measurements over the North Atlantic and a first comparison

1999 ◽  
Vol 26 (18) ◽  
pp. 2849-2852 ◽  
Author(s):  
K.-H. Wohlfrom ◽  
T. Hauler ◽  
F. Arnold ◽  
H. Singh
Keyword(s):  
North Atlantic ◽  
Lower Stratosphere ◽  
Free Troposphere ◽  
The North ◽  
The North Atlantic

scholarly journals The influence of boreal biomass burning emissions on the distribution of tropospheric ozone over North America and the North Atlantic during 2010

2012 ◽  
Vol 12 (4) ◽  
pp. 2077-2098 ◽  
Author(s):  
M. Parrington ◽  
P. I. Palmer ◽  
D. K. Henze ◽  
D. W. Tarasick ◽  
E. J. Hyer ◽  
...  
Keyword(s):  
North America ◽  
Biomass Burning ◽  
North Atlantic ◽  
Tropospheric Ozone ◽  
Free Troposphere ◽  
Scaling Factors ◽  
The North ◽  
Ozone Distribution ◽  
The North Atlantic ◽  
Satellite Instruments

Abstract. We have analysed the sensitivity of the tropospheric ozone distribution over North America and the North Atlantic to boreal biomass burning emissions during the summer of 2010 using the GEOS-Chem 3-D global tropospheric chemical transport model and observations from in situ and satellite instruments. We show that the model ozone distribution is consistent with observations from the Pico Mountain Observatory in the Azores, ozonesondes across Canada, and the Tropospheric Emission Spectrometer (TES) and Infrared Atmospheric Sounding Instrument (IASI) satellite instruments. Mean biases between the model and observed ozone mixing ratio in the free troposphere were less than 10 ppbv. We used the adjoint of GEOS-Chem to show the model ozone distribution in the free troposphere over Maritime Canada is largely sensitive to NOx emissions from biomass burning sources in Central Canada, lightning sources in the central US, and anthropogenic sources in the eastern US and south-eastern Canada. We also used the adjoint of GEOS-Chem to evaluate the Fire Locating And Monitoring of Burning Emissions (FLAMBE) inventory through assimilation of CO observations from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument. The CO inversion showed that, on average, the FLAMBE emissions needed to be reduced to 89% of their original values, with scaling factors ranging from 12% to 102%, to fit the MOPITT observations in the boreal regions. Applying the CO scaling factors to all species emitted from boreal biomass burning sources led to a decrease of the model tropospheric distributions of CO, PAN, and NOx by as much as −20 ppbv, −50 pptv, and −20 pptv respectively. The modification of the biomass burning emission estimates reduced the model ozone distribution by approximately −3 ppbv (−8%) and on average improved the agreement of the model ozone distribution compared to the observations throughout the free troposphere, reducing the mean model bias from 5.5 to 4.0 ppbv for the Pico Mountain Observatory, 3.0 to 0.9 ppbv for ozonesondes, 2.0 to 0.9 ppbv for TES, and 2.8 to 1.4 ppbv for IASI.

scholarly journals Importance of the Saharan Heat Low on the control of the North Atlantic free tropospheric humidity deduced from IASI δD observations

2017 ◽  
Author(s):  
Jean-Lionel Lacour ◽  
Cyrille Flamant ◽  
Camille Risi ◽  
Cathy Clerbaux ◽  
Pierre-François Coheur
Keyword(s):  
North Atlantic ◽  
Turbulent Mixing ◽  
Added Value ◽  
Free Troposphere ◽  
Air Masses ◽  
Annual Variations ◽  
The North ◽  
The North Atlantic ◽  
Different Sources ◽  
Heat Low

Abstract. The isotopic composition of water vapour in the North Atlantic free troposphere is investigated with IASI measurements of the D/H ratio (δD) above the ocean. We show that in the vicinity of West Africa, the seasonality of δD is particularly strong (160 ‰), which is related with the installation of the Saharan Heat Low (SHL) during summertime. The SHL indeed largely influences the dynamic in that region by producing deep turbulent mixing layers, yielding a specific water vapor isotopic footprint. The influence of the SHL on the isotopic budget is analysed at various time and space scales and is shown to be large, highlighting the importance of the SHL dynamics on the moistening and the HDO-enrichment of the free troposphere over the North Atlantic. We also report important inter-annual variations of δD above Izana (Canary Islands) that we interpret, using backward trajectory analyses, in terms of the ratio of air-masses coming from the North Atlantic and air-masses coming from the African continent. Finally, we present spatial distributions of δD and humidity above the North Atlantic and we show that the different sources and dehydration pathways controlling the humidity can be disentangled thanks to the added value of δD observations.

scholarly journals OH and HO2chemistry in the North Atlantic free troposphere

1999 ◽  
Vol 26 (20) ◽  
pp. 3077-3080 ◽  
Author(s):  
W. H. Brune ◽  
D. Tan ◽  
I. F. Faloona ◽  
L. Jaeglé ◽  
D. J. Jacob ◽  
...  
Keyword(s):  
North Atlantic ◽  
Free Troposphere ◽  
The North ◽  
The North Atlantic

scholarly journals Free-troposphere ozone and carbon monoxide over the North Atlantic for 2001–2011

2013 ◽  
Vol 13 (24) ◽  
pp. 12537-12547 ◽  
Author(s):  
A. Kumar ◽  
S. Wu ◽  
M. F. Weise ◽  
R. Honrath ◽  
R. C. Owen ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
North Atlantic ◽  
Transport Model ◽  
Measurement Data ◽  
Free Troposphere ◽  
Chemical Transport Model ◽  
Significance Level ◽  
The Past ◽  
The North ◽  
The North Atlantic

Abstract. In situ measurements of carbon monoxide (CO) and ozone (O3) at the Pico Mountain Observatory (PMO) located in the Azores, Portugal, are analyzed together with results from an atmospheric chemical transport model (GEOS-Chem) and satellite remote sensing data (AIRS (Atmospheric Infrared Sounder) for CO, and TES (Tropospheric Emission Spectrometer) for O3) to examine the evolution of free-troposphere CO and O3 over the North Atlantic for 2001–2011. GEOS-Chem captured the seasonal cycles for CO and O3 well but significantly underestimated the mixing ratios of CO, particularly in spring. Statistically significant (using a significance level of 0.05) decreasing trends were found for both CO and O3 based on harmonic regression analysis of the measurement data. The best estimates of the possible trends for CO and O3 measurements are −0.31 ± 0.30 (2-σ) ppbv yr−1 and −0.21 ± 0.11 (2-σ) ppbv yr−1, respectively. Similar decreasing trends for both species were obtained with GEOS-Chem simulation results. The most important factor contributing to the decreases in CO and O3 at PMO over the past decade is the decline in anthropogenic emissions from North America, which more than compensate for the impacts from increasing Asian emissions. It is likely that climate change in the past decade has also affected the intercontinental transport of O3.

scholarly journals Free troposphere ozone and carbon monoxide over the North Atlantic for 2001–2011

2013 ◽  
Vol 13 (6) ◽  
pp. 15377-15407 ◽  
Author(s):  
A. Kumar ◽  
S. Wu ◽  
M. F. Weise ◽  
R. Honrath ◽  
R. C. Owen ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
North Atlantic ◽  
Measurement Data ◽  
Free Troposphere ◽  
Significance Level ◽  
Mixing Ratios ◽  
The North ◽  
Source Regions ◽  
The North Atlantic ◽  
The Impact

Abstract. In-situ measurements of carbon monoxide (CO) and ozone (O3) at the Pico Mountain Observatory (PMO) located in the Azores, Portugal are analyzed together with results from atmospheric chemical transport modeling (GEOS-Chem) and satellite remote sensing (AIRS for CO and TES for O3) to examine the evolution of free-troposphere CO and O3 over the North Atlantic for 2001–2011. GEOS-Chem captured the seasonal cycles for CO and O3 well but significantly underestimated the mixing ratios of CO, particularly in spring. Statistically significant (using a significance level of 0.05) decreasing trends were found for both CO and O3 based on harmonic regression analysis of the measurement data. The best estimates of the trend for CO and O3 measurements are −0.31 ± 0.30 (2-σ) ppbv yr−1 and −0.21 ± 0.11 (2-σ) ppbv yr−1, respectively. Similar decreasing trends for both species were obtained with GEOS-Chem simulation results. The major factor contributing to the reported decrease in CO and O3 mixing ratios at PMO over the past decade is the decline in anthropogenic CO and O3-precursor emissions in regions such as North America and Europe. The increase in Asian emissions does not seem to outweigh the impact of these declines resulting in overall decreasing trends for both CO and O3. For O3, however, increase in atmospheric water vapor content associated with climate change also appears to be a contributing factor causing enhanced destruction of the O3 during transport from source regions. These hypotheses are supported by results from the GEOS-Chem tagged CO and tagged O3 simulations.

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