Spatio–temporal distribution of absorbing aerosols over Pakistan retrieved from OMI onboard Aura satellite

Tariq, Salman; Ali, M. Tanseer

doi:10.5094/apr.2015.030

Cited by 49 publications

(20 citation statements)

References 30 publications

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“…In this study, we have used the scatter plot of AAE and EAE to categorize dominant aerosol types over Karachi. We have considered EAE < 1.0 and 0.7 < AAE < 1.3, EAE > 0.8 and AAE > 1.3, and EAE > 1 and AAE > 1.2 to represent urban/ industrial aerosols, desert dust aerosols, and biomass burning aerosols, respectively [7,29]. e remaining cases that do not belong to any of the aforementioned groups are referred to as mixed type of aerosols.…”

Section: Identification Of Aerosol Types Optical and Physicalmentioning

confidence: 99%

“…As far as aerosol concentrations and their properties are concerned, Karachi is not a well-studied location. In particular, very few studies have used the remote sensing techniques to monitor aerosols over Pakistan (e.g., [4][5][6][7]). Alam et al [5] tried to characterize the aerosol properties by using the data for small duration (1 year).…”

Section: Introductionmentioning

confidence: 99%

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Ground-Based Remote Sensing of Aerosol Properties over a Coastal Megacity of Pakistan

Tariq

Haq

2018

Advances in Meteorology

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Atmospheric aerosols are considered to be an important constituent of Earth’s atmosphere because of their climatic, environmental, and health effects. Therefore, while studying the global climate change, investigation of aerosol concentrations and properties is essential both at local and regional levels. In this paper, we have used relatively long-term Aerosol Robotic Network (AERONET) data during September 2006–August 2014 to analyze aerosol properties such as aerosol optical depth at 500 nm (AOD), Ångström exponent (440–870 nm) (AE), refractive index (RI), and asymmetry parameter over Karachi, a coastal megacity of Pakistan. The average annual values of AOD and AE were found to be 0.48 ± 0.20 and 0.59 ± 0.29, respectively. The peak (0.88 ± 0.31) AOD was recorded in July with corresponding AE of 0.30 ± 0.22 representing reasonably higher concentration of coarse size particles over Karachi. The cluster analysis using the scatter plot between absorption AE and extinction AE revealed that desert dust prevailed in the atmosphere of Karachi in spring and summer, while biomass burning aerosols dominate in autumn and winter. The peak values of volume concentrations of coarse and fine-mode particulate matter were found in summer and autumn, respectively. Also, we found significant growing trend in single-scattering albedo with wavelength, indicating the domination of dust particles during summer and spring. The peak value of the real part of the RI was observed in spring (1.53) and modest in winter (1.50). On the contrary, the peak value of the imaginary part of the RI was observed to be constantly elevated in winter and lesser in spring.

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Section: Identification Of Aerosol Types Optical and Physicalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ground-Based Remote Sensing of Aerosol Properties over a Coastal Megacity of Pakistan

Tariq

Haq

2018

Advances in Meteorology

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“…Main causes of aerosols in Lahore are biomass burning, emissions from vehicular and industrial activities [59,60]. It was also reported that aerosols formation in Lahore is influenced by transportation of particles generated from the burning of agricultural biomass [12,[61][62][63][64]. In winters Lahore's visibility is limited to 50 m or less [65] causing severe problems for trade and daily commute as well as intercity travel.…”

Section: Resultsmentioning

confidence: 99%

Trends of Aerosol Optical Thickness Using VIIRS S-NPP during Fog Episodes in Pakistan and India

et al. 2021

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Aerosol Optical Thickness (AOT) is one of the important parameters for assessing regional and global level of climate change. Fog episodes have considerably increased in south Asia because of environmental factors, and the burning of agricultural residue leads to major social and economic problems. In present study, Mann-Kendall trend analysis of AOT and active fire events was done, and their significance were assessed using long-term (October 2012–February 2020) remote sensing data derived smog maps. Visible Infrared Imaging Radiometer Suite National Polar Partnership (VIIRS N-PP) was used to map AOT episodes over the northern region of Pakistan and India. Results reveal that AOT displays a significantly decreasing trend over the northern and eastern region of Pakistan and a similar decreasing trend from the Western to Eastern region of India. Furthermore, active fire events have a significantly increasing trend at the Northern region of Pakistan. However, fire events have a significantly decreasing trend over the southern and southeastern region of India. Additionally, statistically significant decreasing trends were observed for AOT over Chakwal (p-value = 0.2, Z_MK = −2.3) and Patiala (p-value = 0.15, Z_MK = −3.2). Fire events have a significantly increasing trend for Dera Ismail Khan (p-value = 0.01, Z_MK = 1.9), Jhang (p-value = 0.01, Z_MK = 1.9), and Chakwal (p-value = 0.01, Z_MK = 1.8), while they are significantly decreasing trend near New Delhi (p-value = 0.2, Z_MK = −0.9), Aligarh (p-value = 0.15, Z_MK = −0.9) and Patiala (p-value = 0.2, Z_MK = −0.8).

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“…3.6 DS days year −1 (moderate frequency), for winter and post‐monsoon, the number of DS days year −1 were found to be 1.1 (low frequency) and 0.1 (very low frequency). Tariq and Ali () presented the spatio‐temporal distribution of absorbing aerosols (e.g. dust) over Pakistan retrieved from Ozone Monitoring Instrument (OMI) onboard Aura satellite (December 2004 to November 2008) and found that dust started to appear in the month of April reaching its maximum in the month of June.…”

Section: Analysis and Discussionmentioning

confidence: 99%

Seasonal assessment and classification of aerosols transported to Lahore using AERONET and MODIS deep blue retrievals

Zafar¹,

Zafar

Holben

2017

Intl Journal of Climatology

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Daily measurements of aerosol optical depth ( ) and Ångstrom wavelength exponent ( ) acquired from Aerosol Robotic Network (AERONET) and Moderate Resolution Imaging Spectrometer (MODIS) are analysed over Lahore -an urban city of Pakistan (period: 2010Pakistan (period: -2014 to investigate contribution of different types of aerosols originating from both local and regional source locations. The obtained annual averages (mean ± standard deviation) for AERONET retrievals of (500 nm) and (440-870 nm) are 0.68 ± 0.37 (0.08-2.91) and 0.99 ± 0.33 (0-1.8), respectively. Of all the sources, 61% are found within Pakistan, 11% in India, 19% in Afghanistan, 6% in Iran and 2% in Saudi Arabia with seasonal contributions of 35, 25, 23 and 17% in pre-monsoon, monsoon, winter and post-monsoon, respectively. The bimodal distributions of show dominance of coarse-mode particles during pre-monsoon, fine-mode particles during post-monsoon and presence of both coarse-mode and fine-mode particles during winter and monsoon with winter showing more fine-mode particles. Two broad classes of aerosols namely desert dust (DD) and biomass burning/urban industrial (BU) are identified with criteria, e.g. ≥ 0.3 and ≤ 0.75 indicating presence of DD while ≥ 0.2 and ≥ 1.15 indicating BU. The frequency of occurrence (FOO) of DD and BU aerosols is further identified by applying classification criteria over Aqua-MODIS deep blue retrievals. The FOO identifies anthropogenic activity on-going throughout the year, disrupted with DD aerosols only during pre-monsoon and monsoon. The maximum dust activity is seen over Indo-Gangetic plains (IGP) (localized maxima: 35-45%) and the Arabian peninsula (>55%) during pre-monsoon, while maximum BU aerosols are found over IGP, central and south-eastern plains of India and the state of Gujarat (localized maxima: >70%) in winter and post-monsoon. KEY WORDS aerosol optical depth; Ångström wavelength exponent; long-range transport; AERONET; HYSPLIT; MODIS deep blue; desert dust/urban-industrial aerosols

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Spatio–temporal distribution of absorbing aerosols over Pakistan retrieved from OMI onboard Aura satellite

Cited by 49 publications

References 30 publications

Ground-Based Remote Sensing of Aerosol Properties over a Coastal Megacity of Pakistan

Ground-Based Remote Sensing of Aerosol Properties over a Coastal Megacity of Pakistan

Trends of Aerosol Optical Thickness Using VIIRS S-NPP during Fog Episodes in Pakistan and India

Seasonal assessment and classification of aerosols transported to Lahore using AERONET and MODIS deep blue retrievals

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