Dr
Jaroslav Resler
(Institute of Computer Science The Czech Academy of Sciences, Prague)
The radiative transfer model represents one of key components of the urban climate model. The scalability of the first version described in the paper [Resler et al 2017] was lower than the scalability of the rest of the PALM-4U model. It allowed to process domains up to extent of a few hundreds of gridpoints in each dimension while the required domains reached the extent of thousands gridpoints. We successively developed new versions 2.0, 2.5 and 3.0 of the RTM model which improved the performance and scalability in orders. It was achieved using different algorithms and the discretization of the problem and by optimization of the MPI communications. The new version is able to process domains in extent of order thousands gridpoints in each direction with very little overhead to the PALM model core and with similar accuracy to the model v. 1.0. We demonstrate the performance and results of the model on pilot testing domains from Prague and Berlin processed inside the project UrbiPragensi.
References
The model PALM-4U web pages: https://www.palm4u.org
PALM-4U developers page: https://palm.muk.uni-hannover.de/trac/wiki/aboutus
Resler, J., Krč, P., Belda, M., Juruš, P., Benešová, N., Lopata, J., Vlček, O., Damašková, D., Eben, K., Derbek, P., Maronga, B., and Kanani-Sühring, F.: PALM-USM v1.0: A new urban surface model integrated into the PALM large-eddy simulation model, Geosci. Model Dev., 10, 3635-3659, https://doi.org/10.5194/gmd-10-3635-2017, 2017.
Summary
A new version of the radiative transfer model (RTM) for model PALM-4U has been developed. Besides the new features, the performance and scalability of RTM was greatly improved and allows now to process efficiently domains with extent of thousand grids in every direction. This was achieved by algorithmic changes as well as by optimizations of the MPI communication. We present the new RTM model and its performance tests as well as its comparison with the older version.
Dr
Jan Geletič
(Institute of Computer Science The Czech Academy of Sciences, Prague)
Dr
Jaroslav Resler
(Institute of Computer Science The Czech Academy of Sciences, Prague)
Mr
Pavel Krč
(Institute of Computer Science The Czech Academy of Sciences, Prague)
