WP-P2: 3D radiation and course grid techniques

Goals of the project:

We will implement an alternative three-dimensional radiation scheme to enhance the calculation of the longwave divergence within the urban canopy yielding a more realistic description of the cooling of air in a city during nighttime. In addition, this scheme considers the air constituents in the urban canopy layer and the three-dimensional casting of shadows from clouds.

Tasks of the project:

WP-P2.1: Implementation of buildings in the 3D-radiative transfer model 'TenStream' and the validation against the benchmark Monte-Carlo model MYSTIC and coupling of the 3D radiative transfer model to the PALM-4U model.

Project structure:

This work package is conducted at LMU, Munich in close cooperation with [UC]² partners at HUB (Salim, Schubert).

Deliverables:

DL1 (month 18): Implementation of buildings in the 'TenStream' model

DL2 (month 24): Evaluation and comparison with MYSTIC

DL3 (month 30): Coupling of the 'TenStream' model to PALM-4U

Progress so far:

As a first step, we enhanced MYSTIC to be able to compute complex buildings and did a study on the influence of said complex surfaces in urban canopies. The following tasks has been completed:

• Consideration of rural and urban surfaces (including orography) in the coupling of TenStream-PALM
• Development of concepts for 3D vegetation in TenStream-PALM
• Adaption of DCEP-PALM to the latest PALM version

References:

Emde, Buras, Kylling, Mayer, Gasteiger, Hamann, Richter, Pause, Downling, Bugliaro, 2016, The libRadtran software package for radiative transfer calculations (version 2.0.1), Geoscientific Model Development, ​https://doi.org/10.5194/gmd-9-1647-2016.

Jakub, F., Mayer, B., 2015, A three-dimensional parallel radiative transfer model for atmospheric heating rates for use in cloud resolving models—The TenStream? solver, Journal of Quantitative Spectroscopy and Radiative Transfer. Elsevier BV 163: 63–71. ​https://doi.org/10.1016/j.jqsrt.2015.05.003.

Contacts:

bernhard.mayer[at]physik.uni-muenchen.de

fabian.jakub[at]physik.uni-muenchen.de

sebastian.schubert[at]geo.hu-berlin.de