Three-dimensional radiative transfer
Except for rare cloudless situations over flat, homogeneous terrain, a one-dimensional description of the atmosphere is usually incomplete. Realistic clouds, topography, changing surface albedo, and low sun create a genuinely three-dimensional radiation field.
Clouds
Clouds strongly influence the atmospheric radiation budget. Their internal variability and three-dimensional geometry complicate the relationship between local measurements and area-averaged quantities relevant to weather and climate.
Remote sensing of aerosols and clouds
We derive aerosol and cloud properties from active and passive observations made at the ground and aboard research aircraft. Physically realistic forward models connect the measured radiances to atmospheric properties.
Parameterization of radiative transfer in cloud and weather models
We develop improved parameterizations for the three-dimensional treatment of solar and thermal radiative transfer in cloud and weather models.
Assimilation of visible satellite observations
In close collaboration with the German Weather Service (DWD), we develop fast radiative-transfer operators that enable visible satellite observations to improve numerical weather prediction.