scholarly journals Source attribution and interannual variability of Arctic pollution in spring constrained by aircraft (ARCTAS, ARCPAC) and satellite (AIRS) observations of carbon monoxide

2010 ◽  
Vol 10 (3) ◽  
pp. 977-996 ◽  
Author(s):  
J. A. Fisher ◽  
D. J. Jacob ◽  
M. T. Purdy ◽  
M. Kopacz ◽  
P. Le Sager ◽  
...  

Abstract. We use aircraft observations of carbon monoxide (CO) from the NASA ARCTAS and NOAA ARCPAC campaigns in April 2008 together with multiyear (2003–2008) CO satellite data from the AIRS instrument and a global chemical transport model (GEOS-Chem) to better understand the sources, transport, and interannual variability of pollution in the Arctic in spring. Model simulation of the aircraft data gives best estimates of CO emissions in April 2008 of 26 Tg month−1 for Asian anthropogenic, 9.4 for European anthropogenic, 4.1 for North American anthropogenic, 15 for Russian biomass burning (anomalously large that year), and 23 for Southeast Asian biomass burning. We find that Asian anthropogenic emissions are the dominant source of Arctic CO pollution everywhere except in surface air where European anthropogenic emissions are of similar importance. Russian biomass burning makes little contribution to mean CO (reflecting the long CO lifetime) but makes a large contribution to CO variability in the form of combustion plumes. Analysis of two pollution events sampled by the aircraft demonstrates that AIRS can successfully observe pollution transport to the Arctic in the mid-troposphere. The 2003–2008 record of CO from AIRS shows that interannual variability averaged over the Arctic cap is very small. AIRS CO columns over Alaska are highly correlated with the Ocean Niño Index, suggesting a link between El Niño and Asian pollution transport to the Arctic. AIRS shows lower-than-average CO columns over Alaska during April 2008, despite the Russian fires, due to a weakened Aleutian Low hindering transport from Asia and associated with the moderate 2007–2008 La Niña. This suggests that Asian pollution influence over the Arctic may be particularly large under strong El Niño conditions.

2019 ◽  
Author(s):  
Matthew J. Rowlinson ◽  
Alexandru Rap ◽  
Stephen R. Arnold ◽  
Richard J. Pope ◽  
Martyn P. Chipperfield ◽  
...  

Abstract. The growth rate of global methane (CH4) concentrations has a strong interannual variability which is believed to be driven largely by fluctuations in CH4 emissions from wetlands and wildfires, as well as changes to the atmospheric sink. The El Niño Southern Oscillation (ENSO) is known to influence fire occurrence, wetland emission and atmospheric transport, but there are still important uncertainties associated with the exact mechanism and magnitude of this influence. Here we use a modelling approach to investigate how fires and meteorology control the interannual variability of global carbon monoxide (CO), CH4 and ozone (O3) concentrations, particularly during large El Niño events. Using a three-dimensional chemical transport model (TOMCAT) coupled to a sophisticated aerosol microphysics scheme (GLOMAP) we simulate changes to CO, hydroxyl radical (OH) and O3 for the period 1997–2014. We then use an offline radiative transfer model to quantify the impact of changes to atmospheric composition as a result of specific drivers. During the El Niño event of 1997–1998, there were increased emissions from biomass burning globally. As a result, global CO concentrations increased by more than 40 %. This resulted in decreased global mass-weighted tropospheric OH concentrations of up to 9 % and a resulting 4 % increase in the CH4 atmospheric lifetime. The change in CH4 lifetime led to a 7.5 ppb yr−1 increase in global mean CH4 growth rate in 1998. Therefore biomass burning emission of CO could account for 72 % of the total effect of fire emissions on CH4 growth rate in 1998. Our simulations indicate variations in fire emissions and meteorology associated with El Niño have opposing impacts on tropospheric O3 burden. El Niño-related atmospheric transport changes decrease global tropospheric O3 concentrations leading to a −0.03 Wm−2 change in O3 radiative effect (RE). However, enhanced fire emission of precursors such as nitrous oxides (NOx) and CO increase O3 RE by 0.03 Wm−2. While globally the two mechanisms nearly cancel out, causing only a small change in global mean O3 RE, the regional changes are large   up to −0.33 Wm−2 with potentially important consequences for atmospheric heating and dynamics.


2005 ◽  
Vol 18 (8) ◽  
pp. 1247-1262 ◽  
Author(s):  
Joshua Larson ◽  
Yaping Zhou ◽  
R. Wayne Higgins

Abstract The climatology and interannual variability of landfalling tropical cyclones and their impacts on precipitation in the continental United States and Mexico are examined. The analysis is based on National Hurricane Center 6-hourly tropical cyclone track data for the Atlantic and eastern Pacific basins and gridded daily U.S. precipitation data for the period August–October 1950–98. Geographic maps of total tropical cyclone strike days, and the mean and maximum percentage of precipitation due to tropical cyclones, are examined by month. To make the procedures objective, it is assumed that precipitation is symmetric about the storm’s center. While this introduces some uncertainty in the analysis, sensitivity tests show that this assumption is reasonable for precipitation within 5° of the circulation center. The relationship between landfalling tropical cyclones and two leading patterns of interannual climate variability—El Niño–Southern Oscillation (ENSO) and the Arctic Oscillation (AO)—are then examined. Relationships between tropical cyclone frequency and intensity and composites of 200-hPa geopotential height and wind shear anomalies are also examined as a function of ENSO phase and AO phase using classifications devised at the Climate Prediction Center. The data show that tropical cyclone activity in the Atlantic basin is modulated on both seasonal and intraseasonal time scales by the AO and ENSO and that impact of the two modes of climate variability is greater together than apart. This suggests that, during La Niña conditions, atmospheric circulation is more conducive to activity in the main development region during AO-positive conditions than during AO-negative ones and that, during El Niño conditions, atmospheric circulation appears even less conducive to tropical cyclone development during the negative phase of the AO than during the positive phase.


2009 ◽  
Vol 9 (5) ◽  
pp. 19035-19080 ◽  
Author(s):  
J. A. Fisher ◽  
D. J. Jacob ◽  
M. T. Purdy ◽  
M. Kopacz ◽  
P. Le Sager ◽  
...  

Abstract. We use aircraft observations of carbon monoxide (CO) from the NASA ARCTAS and NOAA ARCPAC campaigns in April 2008 together with multiyear (2003–2008) CO satellite data from the AIRS instrument and a global chemical transport model (GEOS-Chem) to better understand the sources, transport, and interannual variability of pollution in the Arctic in spring. Model simulation of the aircraft data gives best estimates of CO emissions in April 2008 of 26 Tg month


2019 ◽  
Vol 19 (13) ◽  
pp. 8669-8686 ◽  
Author(s):  
Matthew J. Rowlinson ◽  
Alexandru Rap ◽  
Stephen R. Arnold ◽  
Richard J. Pope ◽  
Martyn P. Chipperfield ◽  
...  

Abstract. The interannual variability of the greenhouse gases methane (CH4) and tropospheric ozone (O3) is largely driven by natural variations in global emissions and meteorology. The El Niño–Southern Oscillation (ENSO) is known to influence fire occurrence, wetland emission and atmospheric circulation, affecting sources and sinks of CH4 and tropospheric O3, but there are still important uncertainties associated with the exact mechanism and magnitude of this effect. Here we use a modelling approach to investigate how fires and meteorology control the interannual variability of global carbon monoxide (CO), CH4 and O3 concentrations, particularly during large El Niño events. Using a three-dimensional chemical transport model (TOMCAT) coupled to a sophisticated aerosol microphysics scheme (GLOMAP) we simulate changes to CO, hydroxyl radical (OH) and O3 for the period 1997–2014. We then use an offline radiative transfer model to quantify the climate impact of changes to atmospheric composition as a result of specific drivers. During the El Niño event of 1997–1998, there were increased emissions from biomass burning globally, causing global CO concentrations to increase by more than 40 %. This resulted in decreased global mass-weighted tropospheric OH concentrations of up to 9 % and a consequent 4 % increase in the CH4 atmospheric lifetime. The change in CH4 lifetime led to a 7.5 ppb yr−1 increase in the global mean CH4 growth rate in 1998. Therefore, biomass burning emission of CO could account for 72 % of the total effect of fire emissions on CH4 growth rate in 1998. Our simulations indicate that variations in fire emissions and meteorology associated with El Niño have opposing impacts on tropospheric O3 burden. El Niño-related changes in atmospheric transport and humidity decrease global tropospheric O3 concentrations leading to a −0.03 W m−2 change in the O3 radiative effect (RE). However, enhanced fire emission of precursors such as nitrogen oxides (NOx) and CO increase O3 and lead to an O3 RE of 0.03 W m−2. While globally the two mechanisms nearly cancel out, causing only a small change in global mean O3 RE, the regional changes are large – up to −0.33 W m−2 with potentially important consequences for atmospheric heating and dynamics.


2012 ◽  
Vol 12 (16) ◽  
pp. 7543-7555 ◽  
Author(s):  
G. Zeng ◽  
S. W. Wood ◽  
O. Morgenstern ◽  
N. B. Jones ◽  
J. Robinson ◽  
...  

Abstract. We analyse the carbon monoxide (CO), ethane (C2H6) and hydrogen cyanide (HCN) partial columns (from the ground to 12 km) derived from measurements by ground-based solar Fourier Transform Spectroscopy at Lauder, New Zealand (45° S, 170° E), and at Arrival Heights, Antarctica (78° S, 167° E), from 1997 to 2009. Significant negative trends are calculated for all species at both locations, based on the daily-mean observed time series, namely CO (−0.94 ± 0.47% yr−1), C2H6 (−2.37 ± 1.18% yr−1) and HCN (−0.93 ± 0.47% yr−1) at Lauder and CO (−0.92 ± 0.46% yr−1), C2H6 (−2.82 ± 1.37% yr−1) and HCN (−1.41 ± 0.71% yr−1) at Arrival Heights. The uncertainties reflect the 95% confidence limits. However, the magnitudes of the trends are influenced by the anomaly associated with the 1997–1998 El Niño Southern Oscillation event at the beginning of the time series reported. We calculate trends for each month from 1997 to 2009 and find negative trends for all months. The largest monthly trends of CO and C2H6 at Lauder, and to a lesser degree at Arrival Heights, occur during austral spring during the Southern Hemisphere tropical and subtropical biomass burning period. For HCN, the largest monthly trends occur in July and August at Lauder and around November at Arrival Heights. The correlations between CO and C2H6 and between CO and HCN at Lauder in September to November, when the biomass burning maximizes, are significantly larger that those in other seasons. A tropospheric chemistry-climate model is used to simulate CO, C2H6, and HCN partial columns for the period of 1997–2009, using interannually varying biomass burning emissions from GFED3 and annually periodic but seasonally varying emissions from both biogenic and anthropogenic sources. The model-simulated partial columns of these species compare well with the measured partial columns and the model accurately reproduces seasonal cycles of all three species at both locations. However, while the model satisfactorily captures both the seasonality and trends in HCN, it is not able to reproduce the negative trends in either C2H6 or CO. A further simulation assuming a 35% decline of C2H6 and a 26% decline of CO emissions from the industrial sources from 1997 to 2009 largely captures the observed trends of C2H6 and CO partial columns at both locations. Here we attribute trends in HCN exclusively to changes in biomass burning and thereby isolate the influence of anthropogenic emissions as responsible for the long-term decline in CO and C2H6. This analysis shows that biomass burning emissions are the main factors in controlling the interannual and seasonal variations of these species. We also demonstrate contributions of biomass burning emission from different southern tropical and sub-tropical regions to seasonal and interannual variations of CO at Lauder; it shows that long-range transport of biomass burning emissions from southern Africa and South America have consistently larger year-to-year contributions to the background seasonality of CO at Lauder than those from other regions (e.g. Australia and South-East Asia). However, large interannual anomalies are triggered by variations in biomass burning emissions associated with large-scale El Niño Southern Oscillation and prolonged biomass burning events, e.g. the Australian bush fires.


2020 ◽  
Vol 260 ◽  
pp. 114029
Author(s):  
Igor O. Ribeiro ◽  
Erickson O. do Santos ◽  
Carla E. Batista ◽  
Karenn S. Fernandes ◽  
Jianhuai Ye ◽  
...  

2021 ◽  
pp. 5-23
Author(s):  
M. A. Kolennikova ◽  
◽  
P. N. Vargin ◽  
D. Yu. Gushchina ◽  
◽  
...  

The response of the Arctic stratosphere to El Nio is studied with account of its Eastern and Central Pacific types for the period of 1950-2005. The study is based on the regression and composite analysis using the simulations with six CMIP5 coupled climate models and reanalysis data.


2018 ◽  
Vol 373 (1760) ◽  
pp. 20170301 ◽  
Author(s):  
Richard A. Betts ◽  
Chris D. Jones ◽  
Jeff. R. Knight ◽  
Ralph. F. Keeling ◽  
John. J. Kennedy ◽  
...  

In early 2016, we predicted that the annual rise in carbon dioxide concentration at Mauna Loa would be the largest on record. Our forecast used a statistical relationship between observed and forecast sea surface temperatures in the Niño 3.4 region and the annual CO 2 rise. Here, we provide a formal verification of that forecast. The observed rise of 3.4 ppm relative to 2015 was within the forecast range of 3.15 ± 0.53 ppm, so the prediction was successful. A global terrestrial biosphere model supports the expectation that the El Niño weakened the tropical land carbon sink. We estimate that the El Niño contributed approximately 25% to the record rise in CO 2 , with 75% due to anthropogenic emissions. The 2015/2016 CO 2 rise was greater than that following the previous large El Niño in 1997/1998, because anthropogenic emissions had increased. We had also correctly predicted that 2016 would be the first year with monthly mean CO 2 above 400 ppm all year round. We now estimate that atmospheric CO 2 at Mauna Loa would have remained above 400 ppm all year round in 2016 even if the El Niño had not occurred, contrary to our previous expectations based on a simple extrapolation of previous trends. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.


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