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Aerosol optical properties and radiative forcing over mega-city Karachi

Alam, Khan und Trautmann, Thomas und Blaschke, Thomas (2011) Aerosol optical properties and radiative forcing over mega-city Karachi. Atmospheric Research, 101, Seiten 773-782. Elsevier. DOI: 10.1016/j.atmosres.2011.05.007.

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Offizielle URL: http://www.sciencedirect.com/science/article/pii/S0169809511001414

Kurzfassung

Aerosol optical properties have been analyzed through the ground-based Aerosol Robotic Network (AERONET) over the mega city Karachi during August 2006 - €July 2007. The aerosol optical depth (AOD) is strongly dependent on wavelength; for shorter wavelengths AOD values are higher than at longer wavelengths. The results reveal that the monthly average AOD at 500 nm ranges from 0.31 to 0.92 with an annual mean of 0.48±0.18 and monthly averaged Angstrom exponent (Alpha) ranges from 0.17 to 1.05 with an annual mean of 0.49±0.31. The maximum monthly average AOD value of 0.92±0.28 with the corresponding Alpha value of 0.21±0.11 is found for July 2007, while the minimum monthly average AOD value of 0.31±0.11 with the corresponding Alpha value of 0.53±0.13 is recorded for March 2007. The volume size distribution in the coarse mode is higher in summer and lower in winter, whereas in the accumulation mode the volume size distribution is higher in winter than in other seasons due to the hygroscopic growth of aerosol particles. The single scattering albedo (SSA) during spring, autumn and summer seasons shows a slight increase with the wavelength and ranges from 0.88±0.02 to 0.97±0.01. The asymmetry parameter (ASY) is also wavelength dependent and varies from 0.61±0.03 to 0.74±0.02 during the year. The aerosol radiative forcing (ARF) for the whole observation period at the top of the atmosphere (TOA) is in the range of ˆ-7 to -ˆ’35 W/m^2 (average -ˆ’22±6 Wm/^2), at the surface from -ˆ’56 to -ˆ’96 W/m^2 (average -ˆ’73±12 W/m^2), increasing the atmospheric forcing from +38 to +61 W/m^2 (average +51±13 W/m^2). The SBDART-AERONET radiative forcing at the surface and TOA agree with correlation of 0.92 and 0.82, respectively.

Dokumentart:Zeitschriftenbeitrag
Titel:Aerosol optical properties and radiative forcing over mega-city Karachi
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Alam, KhanDepartment of Geography and Geology, University of Salzburg, Hellbrunnerstrasse 34, Salzburg, 5020, Austria
Trautmann, Thomasthomas.trautmann@dlr.de
Blaschke, ThomasDepartment of Geography and Geology, University of Salzburg, Hellbrunnerstrasse 34, Salzburg, 5020, Austria
Datum:Mai 2011
Erschienen in:Atmospheric Research
Referierte Publikation:Ja
In Open Access:Nein
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:101
DOI :10.1016/j.atmosres.2011.05.007
Seitenbereich:Seiten 773-782
Verlag:Elsevier
Status:veröffentlicht
Stichwörter:Aerosol particles, optical properties, AERONET, aerosol optical depth, Angstrom exponent, radiative forcing, megacity, Karachi
HGF - Forschungsbereich:Verkehr und Weltraum (alt)
HGF - Programm:Weltraum (alt)
HGF - Programmthema:W EO - Erdbeobachtung
DLR - Schwerpunkt:Weltraum
DLR - Forschungsgebiet:W EO - Erdbeobachtung
DLR - Teilgebiet (Projekt, Vorhaben):W - Vorhaben Entwicklung von Atmosphärenprozessoren (alt)
Standort: Oberpfaffenhofen
Institute & Einrichtungen:Institut für Methodik der Fernerkundung > Atmosphärenprozessoren
Hinterlegt von: Prof.Dr. Thomas Trautmann
Hinterlegt am:06 Feb 2012 07:43
Letzte Änderung:21 Feb 2013 10:53

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