Increase in upper tropospheric and lower stratospheric aerosol levels and its potential connection with Asian pollution

Vernier, Jean‐Paul; Fairlie, T. D.; Natarajan, M.; Wienhold, F. G.; Bian, Jianchun; Martinsson, Bengt G.; Crumeyrolle, S.; Thomason, L. W.; Bedka, Kristopher M.

doi:10.1002/2014jd022372

Cited by 193 publications

(330 citation statements)

References 38 publications

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“…Layer" is hypothesized to loft pollution during the Asian summer monsoon (Vernier et al, 2011;Vernier et al, 2015). Dust storms can loft dust, particularly effective ice condensation nuclei, to high enough altitudes to co-exist with ice clouds (Klein et al, 2010).…”

Section: Misclassified Cirrus Fringe Filtermentioning

confidence: 99%

CALIPSO lidar level 3 aerosol profile product: version 3 algorithm design

Tackett¹,

Winker²,

Getzewich³

et al. 2018

Preprint

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Abstract. The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) level 3 aerosol profile product reports globally-gridded, quality-screened monthly mean aerosol extinction profiles retrieved by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). This paper describes the quality screening and averaging methods used to 10 generate the version 3 product. The fundamental input data are CALIOP level 2 aerosol extinction profiles and layer classification information (aerosol, cloud, and clear-air). Prior to aggregation, the extinction profiles are quality-screened by a series of filters to reduce the impact of layer detection errors, layer classification errors, extinction retrieval errors, and biases due to an intermittent signal anomaly at the surface. The relative influence of these filters are compared in terms of sample rejection frequency, mean extinction, and mean AOD. The "extinction QC flag" filter is the most influential in 15 preventing high-biases in level 3 mean extinction, while the "misclassified cirrus fringe" filter is most aggressive at rejecting cirrus misclassified as aerosol. The impact of quality screening on monthly mean aerosol extinction is investigated globally and regionally. After applying quality filters, monthly mean AOD is reduced by −24 and −31 % for global ocean and global land, respectively, thus indicating the importance of quality screening.

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Section: Misclassified Cirrus Fringe Filtermentioning

confidence: 99%

CALIPSO lidar level 3 aerosol profile product: version 3 algorithm design

Tackett¹,

Winker²,

Getzewich³

et al. 2018

Preprint

View full text Add to dashboard Cite

show abstract

“…A related phenomenon is the buildup of the Asian tropopause aerosol layer (ATAL; Vernier et al, 2011), which has recently been estimated to cause a significant regional radiative forcing of −0.1 W m −2 (Vernier et al, 2015), cooling the Earth's surface. Hence, transport in the Asian monsoon is likely an important factor for climate change.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2017

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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 quasihorizontally along isentropes above the tropopause into the tropics and NH.

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“…Therefore, another possible pathway through which meteorological covariability can influence our correlation analysis over the ISMR is due to the positive association between the magnitude of the Asian tropopause aerosol layer and AOD. However, the tropopause aerosol layer pathway results in insignificant enhancements of AOD during JJAS by ∼ 0.01-0.02 over south Asia compared to the observed climatological mean AOD (∼ 0.6) (Vernier et al, 2015;Yu et al, 2015). Thus, contributions of the Asian tropopause aerosol layer to the observed positive gradients (Fig.…”

Section: Decoupling the Role Of Meteorologymentioning

confidence: 93%

“…Ground-based remote sensing, satellite observations, aircraft measurements, and modeling studies have documented that aerosols are mainly located within the boundary layer during the monsoon period over the ISMR (Mishra and Shibata, 2012;Misra et al, 2012;Sarangi et al, 2015). But some recent studies have reported that the transport of nearsurface aerosols to the free troposphere by mesoscale convection results in upper-level accumulation during the summer monsoon, termed the Asian tropopause aerosol layer (Chakraborty et al, 2015;Vernier et al, 2015). Therefore, another possible pathway through which meteorological covariability can influence our correlation analysis over the ISMR is due to the positive association between the magnitude of the Asian tropopause aerosol layer and AOD.…”

Section: Decoupling the Role Of Meteorologymentioning

confidence: 99%

Investigation of the aerosol–cloud–rainfall association over the Indian summer monsoon region

et al. 2017

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Abstract. Monsoonal rainfall is the primary source of surface water in India. Using 12 years of in situ and satellite observations, we examined the association of aerosol loading with cloud fraction, cloud top pressure, cloud top temperature, and daily surface rainfall over the Indian summer monsoon region (ISMR). Our results showed positive correlations between aerosol loading and cloud properties as well as rainfall. A decrease in outgoing longwave radiation and an increase in reflected shortwave radiation at the top of the atmosphere with an increase in aerosol loading further indicates a possible seminal role of aerosols in the deepening of cloud systems. Significant perturbation in liquid-and icephase microphysics was also evident over the ISMR. For the polluted cases, delay in the onset of collision-coalescence processes and an enhancement in the condensation efficiency allows for more condensate mass to be lifted up to the mixed colder phases. This results in the higher mass concentration of larger-sized ice-phase hydrometeors and, therefore, implies that the delayed rain processes eventually lead to more surface rainfall. A numerical simulation of a typical rainfall event case over the ISMR using a spectral bin microphysical scheme coupled with the Weather Research Forecasting (WRF-SBM) model was also performed. Simulated microphysics also illustrated that the initial suppression of warm rain coupled with an increase in updraft velocity under high aerosol loading leads to enhanced super-cooled liquid droplets above freezing level and ice-phase hydrometeors, resulting in increased accumulated surface rainfall. Thus, both observational and numerical analysis suggest that high aerosol loading may induce cloud invigoration, thereby increasing surface rainfall over the ISMR. While the meteorological variability influences the strength of the observed positive association, our results suggest that the persistent aerosol-associated deepening of cloud systems and an intensification of surface rain amounts was applicable to all the meteorological sub-regimes over the ISMR. Hence, we believe that these results provide a step forward in our ability to address aerosol-cloud-rainfall associations based on satellite observations over the ISMR.

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Increase in upper tropospheric and lower stratospheric aerosol levels and its potential connection with Asian pollution

Cited by 193 publications

References 38 publications

CALIPSO lidar level 3 aerosol profile product: version 3 algorithm design

CALIPSO lidar level 3 aerosol profile product: version 3 algorithm design

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

Investigation of the aerosol–cloud–rainfall association over the Indian summer monsoon region

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