Airborne solar spectroscopic measurements of nitrogen dioxide column density beneath the boundary layer

A. Y.S. Cheng*, Mau Hing CHAN

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


Airborne atmospheric measurement of nitrogen dioxide (NO2) column density was performed using the solar spectroscopic method. The measurement was carried out at different altitudes, from 460 to 700 meters above sea level during a flight in Hong Kong (22.2°N, 114.1°E), the People's Republic of China (PRC). In the territory, the boundary layer height in a sunny day is about 1000 meters. Below the boundary layer, most of the NO2 exists. The airborne solar spectroscopic measurement gives the NO2 vertical profile below the boundary layer. In particular, the solar spectroscopic measurement requires a solar tracking system to collect the direct sunlight. However, in an acceptable small percentage of error in tracking the sun position, it is possible to collect the direct sunlight manually. In this paper, to reduce the complexity of the experimental setup, the sunlight is collected by a portable miniature CCD spectrometer. In the retrieval of NO 2 column density, the airborne solar spectrum is normalized to a reference solar spectrum, which is taken at a high altitude (11,230 meters) during another flight in Xinjiang (42.208°N, 83.949°E) province, PRC. The column density retrieval is achieved from the normalized solar spectrum using the differential optical absorption spectroscopy. A ground-based off-axis control experiment is also performed to estimate the error in the slant column density from the airborne measurement.

Original languageEnglish
Article number59790T
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2005
EventRemote Sensing of Clouds and the Atmosphere X - Bruges, Belgium
Duration: 19 Sept 200521 Sept 2005

Scopus Subject Areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

User-Defined Keywords

  • Differential absorption spectroscopy
  • Nitrogen dioxide
  • Solar spectrum
  • Vertical column density


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