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Fine Resolution Air Quality Monitoring from a Small Satellite: CHRIS/PROBA

Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Hong Kong
Author to whom correspondence should be addressed.
Sensors 2008, 8(12), 7581-7595;
Received: 3 November 2008 / Revised: 14 November 2008 / Accepted: 17 November 2008 / Published: 27 November 2008
(This article belongs to the Section Remote Sensors, Control, and Telemetry)
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Current remote sensing techniques fail to address the task of air quality monitoring over complex regions where multiple pollution sources produce high spatial variability. This is due to a lack of suitable satellite-sensor combinations and appropriate aerosol optical thickness (AOT) retrieval algorithms. The new generation of small satellites, with their lower costs and greater flexibility has the potential to address this problem, with customised platform-sensor combinations dedicated to monitoring single complex regions or mega-cities. This paper demonstrates the ability of the European Space Agency’s small satellite sensor CHRIS/PROBA to provide reliable AOT estimates at a spatially detailed level over Hong Kong, using a modified version of the dense dark vegetation (DDV) algorithm devised for MODIS. Since CHRIS has no middle-IR band such as the MODIS 2,100 nm band which is transparent to fine aerosols, the longest waveband of CHRIS, the 1,019 nm band was used to approximate surface reflectance, by the subtraction of an offset derived from synchronous field reflectance spectra. Aerosol reflectance in the blue and red bands was then obtained from the strong empirical relationship observed between the CHRIS 1,019 nm, and the blue and red bands respectively. AOT retrievals for three different dates were shown to be reliable, when compared with AERONET and Microtops II sunphotometers, and a Lidar, as well as air quality data at ground stations. The AOT images exhibited considerable spatial variability over the 11 x 11km image area and were able to indicate both local and long distance sources. View Full-Text
Keywords: Aerosol; surface reflectance; CHRIS/PROBA Aerosol; surface reflectance; CHRIS/PROBA
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

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MDPI and ACS Style

Nichol, J.E.; Wong, M.S.; Chan, Y.Y. Fine Resolution Air Quality Monitoring from a Small Satellite: CHRIS/PROBA. Sensors 2008, 8, 7581-7595.

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