Title:	Ocean dynamics on HPC - storage
DNr:	SNIC 2021/6-358
Project Type:	SNIC Medium Storage
Principal Investigator:	Göran Broström <goran.brostrom@marine.gu.se>
Affiliation:	Göteborgs universitet
Duration:	2022-01-01 – 2023-01-01
Classification:	10509
Keywords:

Abstract

This project connects to compuational project 2021/1-33. Sub-projects are. Small-scale dynamics (i.e. meter scale) in tidal flows and how a tidal power plant, Deep Green developed by Minesto, interacts with the flow. The sub-project is carried out in collaboration with company Minesto. Two different codes are used, OpenFOAM and a fortran code for geophysical boundary layer turbulence. Lead Sam Fredriksson, Göran Broström. • The OpenFOAM code produces large number of files and we have frequently used 1,000,000 files, and about 0.5-1 TB during runs. For present project we request 2,000,000 files and 5 TB for storage for OpenFOAM. • The geophysical (LES) turbulence model produces few files but large data-sets, these are typically storage on local computers and rewritten as matlab files. Storage need is between 1-3 TB. Lake and regional lake dynamics (scales 50-1000 m scales) will develop during 2021-2022. This work is in collaboration with Norwegian Meteorological Institute. Lead Göran Broström. • Regional and fjord modelling. Here ROMS (www.myroms.org) is used and running 1 year takes about 3 weeks on 575 cores and produces about 3 TB/year for standard output. Model output is typically stored at local computers but for efficiency we ask for 5 TB. Input files are about 0.5TB. • For lake modeling a lake Vänern simulation creates about 1 TB/year, some is removed as all output are not always needed. Main storage are on local computers (i.e. results are downloaded at end of successful simulation). Input files are about 30 GB. Regional-synoptic scales (1 km-100 km). There is a polynya (opening of approximately 80,000 km2) in the Antarctic Ice cover that re-occurs at irregular intervals (in the mid 70’ties and in 2017-2018). The dynamics of these events and the impact on ocean circulation and water mass transformation is studied using models focusing on km scales. • A 25 year-long simulation of the regional configuration at 1/12° resolution generates about 1.3 TB per 3D field, i.e. about 6TB in total. The 1/60° resolution is much heavier in storage requirement, so only 2D fields are stored in general, except for the last 5 simulated years for later analysis. The storage requirement at this resolution is therefore about 2TB per run. In total, a total of 10-20TB of storage would allow a flexible management of output files generated in this project. Large scale ocean dynamics (10 km -1000 km) and position and dynamics of water mass transformation and connection to fronts and properties of water with respect to density (which depends on temperature, salinity, and pressure in a non-simple way). • The storage requirements for this project are usually rather low, as most simulations are done at coarse resolution. A total of 1TB is sufficient. Total request: We foresee that 35 TB storage and allowance for 2,500,000 files covers our basic needs.