@phdthesis{Osterloh2011,
  author    = {Osterloh, Lukas},
  title     = {Retrieving aerosol microphysical properties from multiwavelength Lidar Data},
  address   = {Potsdam},
  pages     = {125 S.},
  year      = {2011},
  language  = {en}
}
@article{OsterlohBoeckmannNicolaeetal.2013,
  author    = {Osterloh, Lukas and B{\"o}ckmann, Christine and Nicolae, Doina and Nemuc, Anca},
  title     = {Regularized inversion of microphysical atmospheric particle parameters - theory and application},
  series = {Journal of computational physics},
  volume    = {237},
  journal   = {Journal of computational physics},
  number    = {11},
  publisher = {Elsevier},
  address   = {San Diego},
  issn      = {0021-9991},
  doi       = {10.1016/j.jcp.2012.11.040},
  pages     = {79 -- 94},
  year      = {2013},
  abstract  = {Retrieving the distribution of aerosols in the atmosphere via remote sensing techniques is a highly complex task that requires dealing with a wide range of different problems stemming both from Physics and Mathematics. We focus on retrieving this distribution from multi-wavelength lidar data for aerosol ensembles consisting of spherical particles via an iterative regularization technique. The optical efficiencies for spherical scatterers are examined to account for the behavior of the underlying integral equation. The ill-posedness of the problem and the conditioning of the discretized problem are analyzed. Some critical points in the model, like the assumed wavelength-independence of the refractive index and the fixed grid of investigated refractive indices, are studied with regard to their expected impact on the regularized solution. A new Monte-Carlo type method is proposed for retrieval of the refractive index. To validate the results, the developed algorithm is applied to two measurement cases of burning biomass gained from multi-wavelength Raman lidar.},
  language  = {en}
}
@article{BoeckmannOsterloh2014,
  author    = {B{\"o}ckmann, Christine and Osterloh, Lukas},
  title     = {Runge-Kutta type regularization method for inversion of spheroidal particle distribution from limited optical data},
  series = {Inverse problems in science and engineering},
  volume    = {22},
  journal   = {Inverse problems in science and engineering},
  number    = {1},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {1741-5977},
  doi       = {10.1080/17415977.2013.830615},
  pages     = {150 -- 165},
  year      = {2014},
  abstract  = {The Runge-Kutta type regularization method was recently proposed as a potent tool for the iterative solution of nonlinear ill-posed problems. In this paper we analyze the applicability of this regularization method for solving inverse problems arising in atmospheric remote sensing, particularly for the retrieval of spheroidal particle distribution. Our numerical simulations reveal that the Runge-Kutta type regularization method is able to retrieve two-dimensional particle distributions using optical backscatter and extinction coefficient profiles, as well as depolarization information.},
  language  = {en}
}
@article{HoffmannOsterlohStoneetal.2012,
  author    = {Hoffmann, Anne and Osterloh, Lukas and Stone, Robert and Lampert, Astrid and Ritter, Christoph and Stock, Maria and Tunved, Peter and Hennig, Tabea and B{\"o}ckmann, Christine and Li, Shao-Meng and Eleftheriadis, Kostas and Maturilli, Marion and Orgis, Thomas and Herber, Andreas and Neuber, Roland and Dethloff, Klaus},
  title     = {Remote sensing and in-situ measurements of tropospheric aerosol, a PAMARCMiP case study},
  series = {Atmospheric environment : air pollution ; emissions, transport and dispersion, transformation, deposition effects, micrometeorology, urban atmosphere, global atmosphere},
  volume    = {52},
  journal   = {Atmospheric environment : air pollution ; emissions, transport and dispersion, transformation, deposition effects, micrometeorology, urban atmosphere, global atmosphere},
  number    = {3},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {1352-2310},
  doi       = {10.1016/j.atmosenv.2011.11.027},
  pages     = {56 -- 66},
  year      = {2012},
  abstract  = {In this work, a closure experiment for tropospheric aerosol is presented. Aerosol size distributions and single scattering albedo from remote sensing data are compared to those measured in-situ. An aerosol pollution event on 4 April 2009 was observed by ground based and airborne lidar and photometer in and around Ny-Alesund, Spitsbergen, as well as by DMPS, nephelometer and particle soot absorption photometer at the nearby Zeppelin Mountain Research Station. The presented measurements were conducted in an area of 40 x 20 km around Ny-Alesund as part of the 2009 Polar Airborne Measurements and Arctic Regional Climate Model Simulation Project (PAMARCMiP). Aerosol mainly in the accumulation mode was found in the lower troposphere, however, enhanced backscattering was observed up to the tropopause altitude. A comparison of meteorological data available at different locations reveals a stable multi-layer-structure of the lower troposphere. It is followed by the retrieval of optical and microphysical aerosol parameters. Extinction values have been derived using two different methods, and it was found that extinction (especially in the UV) derived from Raman lidar data significantly surpasses the extinction derived from photometer AOD profiles. Airborne lidar data shows volume depolarization values to be less than 2.5\% between 500 m and 2.5 km altitude, hence, particles in this range can be assumed to be of spherical shape. In-situ particle number concentrations measured at the Zeppelin Mountain Research Station at 474 m altitude peak at about 0.18 mu m diameter, which was also found for the microphysical inversion calculations performed at 850 m and 1500 m altitude. Number concentrations depend on the assumed extinction values, and slightly decrease with altitude as well as the effective particle diameter. A low imaginary part in the derived refractive index suggests weakly absorbing aerosols, which is confirmed by low black carbon concentrations, measured at the Zeppelin Mountain as well as on board the Polar 5 aircraft.},
  language  = {en}
}
@misc{BoeckmannOsterloh2014,
  author    = {B{\"o}ckmann, Christine and Osterloh, Lukas},
  title     = {Runge-Kutta type regularization method for inversion of spheroidal particle distribution from limited optical data},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {907},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-44120},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441200},
  pages     = {150 -- 165},
  year      = {2014},
  abstract  = {The Runge-Kutta type regularization method was recently proposed as a potent tool for the iterative solution of nonlinear ill-posed problems. In this paper we analyze the applicability of this regularization method for solving inverse problems arising in atmospheric remote sensing, particularly for the retrieval of spheroidal particle distribution. Our numerical simulations reveal that the Runge-Kutta type regularization method is able to retrieve two-dimensional particle distributions using optical backscatter and extinction coefficient profiles, as well as depolarization information.},
  language  = {en}
}