Seasonal variation of surface and vertical profile of aerosol properties over a tropical urban station Hyderabad, India

Sinha, P. R.; Manchanda, R. K.; Kaskaoutis, Dimitris G.; Kumar, Yogesh; Sreenivasan, S. V.

doi:10.1029/2012jd018039

Cited by 57 publications

(25 citation statements)

References 133 publications

(188 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The study reported that the AOD of elevated aerosol layer could go as high as 0.25 in severe aerosol loading conditions [ Niranjan et al , ]. Sinha et al [] have reported 25% contribution from elevated aerosol layer (above 3.5 km) over Hyderabad during premonsoon, 2009–2010. In another study using MPL, 40–60% contribution of aerosol above 1.0 km during March 2005 were reported over Bangalore [ Satheesh et al , ].…”

Section: Resultsmentioning

confidence: 99%

Elevated aerosol layers and their radiative impact over Kanpur during monsoon onset period

et al. 2016

View full text Add to dashboard Cite

Accurate information about aerosol vertical distribution is needed to reduce uncertainties in aerosol radiative forcing and its effect on atmospheric dynamics. The present study deals with synergistic analyses of aerosol vertical distribution and aerosol optical depth (AOD) with meteorological variables using multisatellite and ground‐based remote sensors over Kanpur in central Indo‐Gangetic Plain (IGP). Micro‐Pulse Lidar Network‐derived aerosol vertical extinction (σ) profiles are analyzed to quantify the interannual and daytime variations during monsoon onset period (May–June) for 2009–2011. The mean aerosol profile is broadly categorized into two layers viz., a surface layer (SL) extending up to 1.5 km (where σ decreased exponentially with height) and an elevated aerosol layer (EAL) extending between 1.5 and 5.5 km. The increase in total columnar aerosol loading is associated with relatively higher increase in contribution from EAL loading than that from SL. The mean contributions of EALs are about 60%, 51%, and 50% to total columnar AOD during 2009, 2010, and 2011, respectively. We observe distinct parabolic EALs during early morning and late evening but uniformly mixed EALs during midday. The interannual and daytime variations of EALs are mainly influenced by long‐range transport and convective capacity of the local emissions, respectively. Radiative flux analysis shows that clear‐sky incoming solar radiation at surface is reduced with increase in AOD, which indicates significant cooling at surface. Collocated analysis of atmospheric temperature and aerosol loading reveals that increase in AOD not only resulted in surface dimming but also reduced the temperature (∼2–3°C) of lower troposphere (below 3 km altitude). Radiative transfer simulations indicate that the reduction of incoming solar radiation at surface is mainly due to increased absorption by EALs (with increase in total AOD). The observed cooling in lower troposphere in high aerosol loading scenario could be understood as a dynamical feedback of EAL‐induced stratification of lower troposphere. Further, the observed radiative effect of EALs increases the stability of the lower troposphere, which could modulate the large‐scale atmospheric dynamics during monsoon onset period. These findings encourage follow‐up studies on the implication of EALs to the Indian summer monsoon dynamics using numerical models.

show abstract

Section: Resultsmentioning

confidence: 99%

Elevated aerosol layers and their radiative impact over Kanpur during monsoon onset period

et al. 2016

View full text Add to dashboard Cite

show abstract

“…At Zhangye station in northwest China, aerosol extinction coefficients in the upper and lower layers decreased with altitude, whereas the coefficient in the middle layer changed slightly, which suggested that aerosol mixing occurred in the middle layer (Zhang et al, 2012a). Sinha et al (2013) found that aerosols within atmospheric boundary layer (ABL) over a tropical urban station Hyderabad, India dominated the column aerosol loading with ABL-AOD, contributing not less than 50 % throughout the year. Over urban locations in South India, BC mass loadings decreased approximately monotonically from the surface to an altitude of 7 km (Safai et al, 2012).…”

Section: Xu Et Al: Similarities and Differences Of Aerosol Opticamentioning

confidence: 99%

Similarities and differences of aerosol optical properties between southern and northern sides of the Himalayas

Panday

et al. 2014

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. The Himalaya mountains along the southern edge of the Tibetan Plateau act as a natural barrier for the transport of atmospheric aerosols from the polluted regions of South Asia to the main body of the Tibetan Plateau. In this study, we investigate the seasonal and diurnal variations of aerosol optical properties measured at two Aerosol Robotic Network (AERONET) sites on the southern side of the Himalaya (Pokhara, 812 m above sea level (a.s.l.) and EVK2-CNR, 5079 m a.s.l. in Nepal) and one on the northern side (Qomolangma (Mt. Everest) station for Atmospheric and Environmental Observation and Research, Chinese Academy of Sciences (QOMS_CAS) in Tibet, 4076 m a.s.l. in China). While observations at QOMS_CAS and EVK2-CNR can generally be representative of a remote background atmosphere, Pokhara is a lower-elevation suburban site with much higher aerosol load due to both the influence of local anthropogenic activities and to its proximity to the Indo-Gangetic Plains. The annual mean aerosol optical depth (AOD) during the investigated period was 0.05 at QOMS_CAS, 0.04 at EVK2-CNR and 0.51 at Pokhara, respectively. Seasonal variations of aerosols are profoundly affected by large-scale atmospheric circulation. Vegetation fires, peaking during April in the Himalayan region and northern India, contribute to a growing fine mode AOD at the three stations. Dust transported to these sites, wind erosion and hydrated/cloudprocessed aerosols lead to an increase in coarse mode AOD during the monsoon season at QOMS_CAS and EVK2-CNR. Meanwhile, coarse mode AOD at EVK2-CNR is higher than at QOMS_CAS in August and September, indicating that the transport of coarse mode aerosols from the southern to the northern side may be effectively reduced. The effect of precipitation scavenging is clearly seen at Pokhara, which sees significantly reduced aerosol loads during the monsoon season. Unlike the seasonal variations, diurnal variations are mainly influenced by meso-scale systems and local topography. The diurnal pattern in precipitation appears to contribute to diurnal changes in AOD through the effect of precipitation scavenging. AOD exhibits diurnal patterns related to emissions in Pokhara, while it does not at the other two high-altitude sites. At EVK2-CNR, the daytime airflow carries aerosols up from lower-altitude polluted regions, leading to increasing AOD, while the other two stations are less influenced by valley winds. Surface heating influences the local convection, which further controls the vertical aerosol exchange and the diffusion rate of pollution to the surrounding areas. Fine and coarse mode particles Published by Copernicus Publications on behalf of the European Geosciences Union. C. Xu et al.: Similarities and differences of aerosol optical propertiesare mixed together on the southern side of the Himalaya in spring, which may lead to the greater inter-annual difference in diurnal cycles of Ångström exponent (AE) at EVK2-CNR than that at QOMS_CAS.

show abstract

“…Over Hyderabad, vertical profile of aerosol particles have been investigated by researchers using aircraft and balloons experimentation in campaign mode (Babu et al, 2011. Sinha et al (2013) used one year in-situ lidar observations to study the aerosol vertical distributions. They found that the ABL aerosols contribute from a minimum of 43.0% to a maximum of 97.9% to the total AOD.…”

Section: Vertical Distribution Of Aerosols Over Hyderabadmentioning

confidence: 99%

“…Vertical profile of ABC calculated following an inversion technique (Klett, 1985) by assuming a constant lidar ratio. However we have assumed different lidar ratios for each season by following Sinha et al (2013). Rayleigh vertical profile is calculated by using real time vertical profile observations of temperature and pressure from descending pass (~01:30 LT) of Atmospheric Infrared Sounder (AIRS) over the study location.…”

Section: Seasonal Variations Of Aerosol Backscatter Coefficient (Abc)mentioning

confidence: 99%

Cross-Sectional View of Atmospheric Aerosols over an Urban Location in Central India

Jose

Gharai

Rao

2017

Aerosol Air Qual. Res.

View full text Add to dashboard Cite

Surface, column and vertically resolved variations of physical and optical properties of atmospheric aerosol over Hyderabad, a tropical urban location in central India are explored on the basis of ground based and satellite retrieved data. Annual mean aerosol optical depth (τ) observed with Microtops sun-photometer is 0.61 ± 0.07 and seasonally it varied from 0.71 ± 0.06 in pre-monsoon to 0.55 ± 0.05 in winter. Aerosol types are categorized based on Ångström exponent (α) and τ relations; revealed that the study region is dominated by mixed type (MT) aerosol followed by urban/industrial aerosols under high τ (HUI) category. A consistent diurnal variation of black carbon (BC) is observed irrespective of seasonal variation with annual BC mass concentration is found to be 9.7 ± 1.9 µg m -3. During Telangana Survey day, which was the least pollutant day showed a reduction of 75% BC concentration during day time in comparison to five years average values, indicating the influence of anthropogenic effect over Hyderabad. Vertical information's on aerosol are analyzed using Cloud Aerosol Lidar Pathfinder Satellite Observations (CALIPSO) and ground based Lidar (LAMP) data. LAMP data analysis shows a significant elevated aerosol layer up to 4 km during pre-monsoon while aerosols are confined below 3 km during post-monsoon and winter. Long term CALIPSO observations revealed that during postmonsoon to winter, the study area is dominated (~60%) by 'urban' aerosol; while during pre-monsoon period ~75% of the aerosol type belongs to 'dusty mix' category. A decline in short wave flux at the top of the atmosphere (0.66 Wm -2 yr -1 ) is observed, as revealed by long term Clouds and Earths Radiant Energy System (CERES) data analysis with higher decline rate observed in winter (1 Wm -2 yr -1 ) followed by pre-monsoon (0.8 Wm -2 yr -1 ).

show abstract

Seasonal variation of surface and vertical profile of aerosol properties over a tropical urban station Hyderabad, India

Cited by 57 publications

References 133 publications

Elevated aerosol layers and their radiative impact over Kanpur during monsoon onset period

Elevated aerosol layers and their radiative impact over Kanpur during monsoon onset period

Similarities and differences of aerosol optical properties between southern and northern sides of the Himalayas

Cross-Sectional View of Atmospheric Aerosols over an Urban Location in Central India

Contact Info

Product

Resources

About