Methane plume over south Asia during the monsoon season: satellite observation and model simulation

Xiong, Xiaozhen; Houweling, Sander; Wei, Jennifer; Maddy, E.; Sun, Fengying; Barnet, Christopher D.

doi:10.5194/acp-9-783-2009

Cited by 125 publications

(117 citation statements)

References 31 publications

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“…In agreement with previous studies (Tobo et al, 2007;Vernier et al, 2011), Fig. 3b Previous studies from model simulations and trajectory analysis show that rapid transport of trace gases and aerosols from Asian boundary layer into the anticyclone is closely linked with the deep ASM convection (Li et al, 2005;Randel and Park, 2006;Park et al, 2007Park et al, , 2009Xiong et al, 2009;Fadnavis et al, 2013Fadnavis et al, , 2014Fadnavis et al, , 2015. We plot longitude-pressure and latitude-pressure cross sections of carbonaceous aerosol from CTRL simulations to understand their transport.…”

Section: Transportation Of Aerosol To the Utlssupporting

confidence: 69%

Potential impact of carbonaceous aerosol on the upper troposphere and lower stratosphere (UTLS) and precipitation during Asian summer monsoon in a global model simulation

et al. 2017

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Abstract. Recent satellite observations show efficient vertical transport of Asian pollutants from the surface to the upper-level anticyclone by deep monsoon convection. In this paper, we examine the transport of carbonaceous aerosols, including black carbon (BC) and organic carbon (OC), into the monsoon anticyclone using of ECHAM6-HAM, a global aerosol climate model. Further, we investigate impacts of enhanced (doubled) carbonaceous aerosol emissions on the upper troposphere and lower stratosphere (UTLS), underneath monsoon circulation and precipitation from sensitivity simulations.The model simulation shows that boundary layer aerosols are transported into the monsoon anticyclone by the strong monsoon convection from the Bay of Bengal, southern slopes of the Himalayas and the South China Sea. Doubling of emissions of both BC and OC aerosols over Southeast Asia (10 • S-50 • N, 65-155 • E) shows that lofted aerosols produce significant warming (0.6-1 K) over the Tibetan Plateau (TP) near 400-200 hPa and instability in the middle/upper troposphere. These aerosols enhance radiative heating rates (0.02-0.03 K day −1 ) near the tropopause. The enhanced carbonaceous aerosols alter aerosol radiative forcing (RF) at the surface by −4.74 ± 1.42 W m −2 , at the top of the atmosphere (TOA) by +0.37 ± 0.26 W m −2 and in the atmosphere by +5.11 ± 0.83 W m −2 over the TP and Indo-Gangetic Plain region • N, 80-110 • E). Atmospheric warming increases vertical velocities and thereby cloud ice in the upper troposphere. Aerosol induced anomalous warming over the TP facilitates the relative strengthening of the monsoon Hadley circulation and increases moisture inflow by strengthening the cross-equatorial monsoon jet. This increases precipitation amounts over India (1-4 mm day −1 ) and eastern China (0.2-2 mm day −1 ). These results are significant at the 99 % confidence level.

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Section: Transportation Of Aerosol To the Utlssupporting

confidence: 69%

Potential impact of carbonaceous aerosol on the upper troposphere and lower stratosphere (UTLS) and precipitation during Asian summer monsoon in a global model simulation

et al. 2017

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“…The simulated al- titude of the acetone plume is consistent with simulations by Park et al (2004) of a plume composed of high mixing ratios of CH 4 , H 2 O and NO x at pressure altitudes included between 300 and 150 hPa, in accordance with observations from the HALOE instrument. The increase of CH 4 is also observed by the AIRS instrument in the altitude interval from 300 to 150 hPa (Xiong et al, 2009).…”

Section: Effects Of Vertical Gradientsmentioning

confidence: 71%

“…A concomitant decrease of ozone was also observed by CARIBIC . Model and satellite data consistently localised high mixing ratios of CH 4 between 60 • E and 120 • E around 30 • N, a region included in our extended South Asian region (Table 2) at and above cruising altitude, at pressure altitudes between 300 and 100 hPa (Park et al, 2004;Xiong et al, 2009). Schuck et al (2010) showed that air masses sampled north of 30 • N generally travel for more than a week, in contrast with air masses south of 30 • N which had ground contact within the last four days prior to sampling.…”

Section: Two Contrasted Transport Conditions: Rapid Uplifting Of Pollmentioning

confidence: 99%

Acetone variability in the upper troposphere: analysis of CARIBIC observations and LMDz-INCA chemistry-climate model simulations

et al. 2011

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Abstract. This paper investigates the acetone variability in the upper troposphere (UT) as sampled during the CARIBIC airborne experiment and simulated by the LMDz-INCA global chemistry climate model. The aim is to (1) describe spatial distribution and temporal variability of acetone; (2) propose benchmarks deduced from the observed data set; and (3) investigate the representativeness of the observational data set.According to the model results, South Asia (including part of the Indian Ocean, all of India, China, and the Indochinese peninsula) and Europe (including Mediterranean Sea) are net source regions of acetone, where nearly 25 % of North Hemispheric (NH) primary emissions and nearly 40 % of the NH chemical production of acetone take place. The impact of these net source regions on continental upper tropospheric acetone is studied by analysing CARIBIC observations of 2006 and 2007 when most flight routes stretched between Frankfurt (Germany) and Manila (Philippines), and by focussing over 3 sub-regions where acetone variability is strong: Europe-Mediterranean, Central South China and South China Sea.Important spatial variability was observed over different scales: (1) east-west positive gradient of annually averaged acetone vmr in UT over the Eurasian continent, namely a factor two increase from east to west; (2) ocean/continent contrast with 50 % enhancement over the continents; (3) the Correspondence to: T. Elias (te@hygeos.com) acetone volume mixing ration (vmr) may vary in summer by more than 1000 pptv within only 5 latitude-longitude degrees; (4) the standard deviation for measurements acquired during a short flight sequence over a sub-region may reach 40 %. Temporal variability is also important: (1) the acetone volume mixing ratio (vmr) in the UT varies with the season, increasing from winter to summer by a factor 2 to 4; (2) a difference as large as 200 pptv may be observed between successive inbound and outbound flights over the same sub-region due to different flight specifications (trajectory in relation to the plume, time of day).A satisfactory agreement for the abundance of acetone is found between model results and observations, with e.g. only 30 % overestimation of the annual average over CentralSouth China and the South China Sea (between 450 and 600 pptv), and an underestimation by less than 20 % over Europe-Mediterranean (around 800 pptv). Consequently, annual budget terms could be computed with LMDz-INCA, yielding a global atmospheric burden of 7.2 Tg acetone, a 127 Tg yr −1 global source/sink strength, and a 21-day mean residence time.Moreover the study shows that LMDz-INCA can reproduce the impact of summer convection over China when boundary layer compounds are lifted to cruise altitude of 10-11 km and higher. The consequent enhancement of acetone vmr during summer is reproduced by LMDz-INCA, to reach agreement on an observed maximum of 970 ± 400 pptv (average during each flight sequence over the defined zone ± standard deviation). The summer enhancement of acetone is characterized by...

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“…Fu et al (2006) suggested that the high altitude of the pollutant maximum could be associated with extremely deep convection over the Tibetan Plateau, which is suggested to detrain even more water vapor, carbon monoxide and possibly other pollutants at the tropopause than the monsoon area itself. However, this seems unlikely, given that the main sources of pollutants are not located on the Tibetan Plateau, and several analyses (Randel and Park, 2006;Park et al, 2007Park et al, , 2008Park et al, , 2009Xiong et al, 2009), using satellite observations and model simulations, have indeed shown that the primary source for the CO and CH 4 maxima in the Tibetan anticyclone is vertical transport of emissions from India and Southeast Asia in the summer monsoon convection, followed by large-scale vertical advection from the main convective detrainment level (around 12 km) to altitudes near the tropopause (∼15-16 km), then trapping within the anticyclone.…”

Section: Pollution In the Tibetan Anticyclonementioning

confidence: 99%

Atmospheric pollutant outflow from southern Asia: a review

2010

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Abstract. Southern Asia, extending from Pakistan and Afghanistan to Indonesia and Papua New Guinea, is one of the most heavily populated regions of the world. Biofuel and biomass burning play a disproportionately large role in the emissions of most key pollutant gases and aerosols there, in contrast to much of the rest of the Northern Hemisphere, where fossil fuel burning and industrial processes tend to dominate. This results in polluted air masses which are enriched in carbon-containing aerosols, carbon monoxide, and hydrocarbons. The outflow and long-distance transport of these polluted air masses is characterized by three distinct seasonal circulation patterns: the winter monsoon, the summer monsoon, and the monsoon transition periods. During winter, the near-surface flow is mostly northeasterly, and the regional pollution forms a thick haze layer in the lower troposphere which spreads out over millions of square km between southern Asia and the Intertropical Convergence Zone (ITCZ), located several degrees south of the equator over the Indian Ocean during this period. During summer, the heavy monsoon rains effectively remove soluble gases and aerosols. Less soluble species, on the other hand, are lifted to the upper troposphere in deep convective clouds, and are then transported away from the region by strong upper tropospheric winds, particularly towards northern Africa and the Mediterranean in the tropical easterly jet. Part of the pollution can reach the tropical tropopause layer, the gateway to the stratosphere. During the monsoon transition periods, the flow across the Indian Ocean is primarily zonal, and strong pollution plumes originating from both southeastern Asia and from Africa spread across the central Indian Ocean. This paper provides a review of the current state of knowledge based on the many observational and modeling studies over the last decades that have examined the southern AsianCorrespondence to: M. G. Lawrence (mark.lawrence@mpic.de) atmospheric pollutant outflow and its large scale effects. An outlook is provided as a guideline for future research, pointing out particularly critical issues such as: resolving discrepancies between top down and bottom up emissions estimates; assessing the processing and aging of the pollutant outflow; developing a better understanding of the observed elevated pollutant layers and their relationship to local sea breeze and large scale monsoon circulations; and determining the impacts of the pollutant outflow on the Asian monsoon meteorology and the regional hydrological cycle, in particular the mountain cryospheric reservoirs and the fresh water supply, which in turn directly impact the lives of over a billion inhabitants of southern Asia.

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Methane plume over south Asia during the monsoon season: satellite observation and model simulation

Cited by 125 publications

References 31 publications

Potential impact of carbonaceous aerosol on the upper troposphere and lower stratosphere (UTLS) and precipitation during Asian summer monsoon in a global model simulation

Potential impact of carbonaceous aerosol on the upper troposphere and lower stratosphere (UTLS) and precipitation during Asian summer monsoon in a global model simulation

Acetone variability in the upper troposphere: analysis of CARIBIC observations and LMDz-INCA chemistry-climate model simulations

Atmospheric pollutant outflow from southern Asia: a review

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