Radiative closure (simulation ↔ measurements) with a complete input/output measurement dataset of supersite Meteorological Observatory Lindenberg (Germany)

In this paper, we apply the method of radiative closure to the measurement dataset of supersite DWD/MOL-RAO (Deutscher Wetterdienst, Meteorological Observatory Lindenberg – Richard Assmann Observatory) in Lindenberg (Tauche) Germany.

The MOL-RAO observatory is a supersite for measurements of atmospheric parameters and ground-based radiative transfer measurements. We use these measurements as input files to perform high accuracy radiative transfer simulations for cloud-free conditions. Some of the measured atmospheric parameters included in the input files are water vapour, ozone, aerosol optical depth for different wavelengths, single scattering albedo, and atmospheric pressure. For longwave simulations, water vapour and temperature profiles with good precision and estimated vertical positions of aerosol layers are provided as inputs.

We compare the results of the high accuracy simulations with ground-based radiation measurements from the highest WMO quality standards. The comparisons are conducted for every minute for broadband radiation (solar diffuse, direct and global) and every six minutes for spectral measurements (direct and global) in the range 290 - 1000 nm with a spectral resolution of 1nm.

After comparing the high accuracy simulation results with broadband and spectral radiation measurements for the same timestamps, we evaluate and improve both the simulation procedure and the measurement of input parameters (atmospheric composition, aerosol amount and properties). This method is called the 'radiative closure.' In the paper, we also present sensitivity analyses to investigate the influence of the different atmospheric parameters on the radiation, particularly the aerosol properties for the radiation in solar wavelengths, vertical profiles of temperature and water vapour, and aerosol properties for the thermal radiation.