A weighted least squares approach to retrieve aerosol layer height over bright surfaces applied to GOME-2 measurements of the oxygen A band for forest fire cases over Europe

A weighted least squares approach to retrieve aerosol layer height over bright surfaces applied to GOME-2 measurements of the oxygen A band for forest fire cases over Europe

Nanda, S. (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI))
Veefkind, j. Pepijn (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI))
De Graaf, Martin (Royal Netherlands Meteorological Institute (KNMI))
Sneep, Maarten (Royal Netherlands Meteorological Institute (KNMI))
Stammes, Piet (Royal Netherlands Meteorological Institute (KNMI))
De Haan, Johan F. (Royal Netherlands Meteorological Institute (KNMI))
Sanders, Abram F.J. (University of Bremen)
Apituley, Arnoud (Royal Netherlands Meteorological Institute (KNMI))
Tuinder, Olaf (Royal Netherlands Meteorological Institute (KNMI))
Levelt, Pieternel Felicitas (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI))

2018-06-07

This paper presents a weighted least squares approach to retrieve aerosol layer height from top-of-atmosphere reflectance measurements in the oxygen A band (758-770g nm) over bright surfaces. A property of the measurement error covariance matrix is discussed, due to which photons travelling from the surface are given a higher preference over photons that scatter back from the aerosol layer. This is a potential source of biases in the estimation of aerosol properties over land, which can be mitigated by revisiting the design of the measurement error covariance matrix. The alternative proposed in this paper, which we call the dynamic scaling method, introduces a scene-dependent and wavelength-dependent modification in the measurement signal-to-noise ratio in order to influence this matrix. This method is generally applicable to other retrieval algorithms using weighted least squares. To test this method, synthetic experiments are done in addition to application to GOME-2A and GOME-2B measurements of the oxygen A band over the August 2010 Russian wildfires and the October 2017 Portugal wildfire plume over western Europe.

http://resolver.tudelft.nl/uuid:15773fec-e985-4548-bc66-66cc14ecabef

https://doi.org/10.5194/amt-11-3263-2018

1867-1381

Atmospheric Measurement Techniques, 11 (6), 3263-3280

Institutional Repository

journal article

© 2018 S. Nanda, j. Pepijn Veefkind, Martin De Graaf, Maarten Sneep, Piet Stammes, Johan F. De Haan, Abram F.J. Sanders, Arnoud Apituley, Olaf Tuinder, Pieternel Felicitas Levelt