Johan De Haan

Johan F. de Haan received the M.S. degree in physics and the Ph.D. degree from the Free University of Amsterdam, Amsterdam, The Netherlands, in 1978 and 1987, respectively. His Ph.D. thesis, entitled “Effects of aerosols on the brightness and polarization of cloudless planetary atmospheres” was defended successfully in 1987 (promoter: Prof. Dr. J. W. Hovenier). The thesis deals with the development of an improved adding/doubling code to calculate the degree of polarization of sunlight scattered by the atmospheres of the Earth and Mars. The code was applied to these atmospheres and effects of aerosols on the scattered light were investigated. Between 1987 and 2003, he was involved in educating Ph.D. students in the Astronomy Department, Free University. He worked together with Ph.D. students on diverse subjects, such as light scattering by nonspherical aerosol particles, and the interpretation of measurements of polarized light scattered by the atmospheres of the Earth, Venus, and Jupiter. Between 1994 and 2000, he worked part-time at the Survey Department of Rijkswaterstaat, Delft, The Netherlands, on the interpretation of remote sensing images of coastal and inland waters. This included the development and application of schemes for atmospheric correction of those images and the improvement of retrieval algorithms for chlorophyll, suspended sediment, and yellow substance. In 2000, he began work at KNMI on OMI retrieval algorithms. He developed a scheme to improve the correction for rotational Raman scattering in the total ozone DOAS algorithm, thereby eliminating errors in the total ozone column of up to 10%. Currently, he is responsible for the OMI ozone profile algorithm, which is being extended to include rotational Raman scattering. Further, he is involved in the OMI cloud retrieval algorithm and is investigating ways to improve the current algorithm that is based on absorption by the $\hbox {O} _{2}$-$\hbox {O} _{2}$ collision complex at 477 nm. In general, specialized knowledge on radiative transfer and a good overall knowledge of numerical techniques are used to extend and improve retrieval algorithms. Special care is taken to ensure that the physics behind the algorithms is sound.