nextGEMS pre-final#

The nextGEMS pre-final simulations build on cycle 3 experience plus adaptations for multi-decadal experiments. This includes improvements in the configuration (updated schemes and features) and some changes in the output. The simulations will be analyzed during the 4th km-scale hackathon in Hamburg in March 2024.

As before, pre-final simulations can be accessed through the nextGEMS intake catalog:

import intake
cat = intake.open_catalog("https://data.nextgems-h2020.eu/catalog.yaml")

IFS-FESOM#

On the IFS-FESOM side, two 30-year simulations (scenario and historical) were run. These are not “pre-final” but rather production simulations. These simulations were run at 9km resolution (on a grid tco1279-NG5)), but with a model physics that mimics behaviour at km-scale, due to a substantially reduced (factor 6) cloud base mass flux in the deep convection scheme. Scientifically, the simulation uses the same IFS as in Cycle 3, but with a few changes to the boundary conditions: * increasing GHG (CMIP6) concentrations, * CONFESS aerosols, * SSP370 (CMIP6) ozone,, * background volcanic aerosol climatology extended with non-zero (non-volcano) year,

From a technical point of view, the output of all fluxes (e.g. precipitation) is not accumulated over each month anymore, but has already been deaccumulated every hour. Note however that to get actual fluxes one needs to divide the fluxes by the seconds elapsed, e.g. 3600 for hourly flux output.

Also, the IFS and FESOM model are now writing both high-frequency and monthly-mean output to the healpix grid, at two resolutions (h512 and h128, or zoom 9 and zoom 7 respectively), in addition to writing to a 0.25° grid.

IFS_9-FESOM_5-production
2020-2050
output on 2 healpix levels and regular 0.25 deg
cat.IFS["IFS_9-FESOM_5-production"]
IFS_9-FESOM_5-production-hist
1990-2020
output on 2 healpix levels and regular 0.25 deg
cat.IFS["IFS_9-FESOM_5-production-hist"]

Both for the scenario and the historical, the daily FESOM ocean variables are found under the streams: ‘2D_daily_healpix512_ocean’ and ‘3D_daily_healpix512_ocean under each run entry.

Cama-Flood is currently been run at 6 arcmin resolution with hourly coupling to provide river discharge and flooded area for both historical and scenario simulations above. Note that for the time being the output is only on a regular lat-lon grid of 6arcmin (=0.1 degrees) and no HEALpix data is available. CaMa-Flood (Yamazaki et al., 2011; 2013; 2014) is designed to simulate the hydrodynamics in continental-scale rivers. The entire river networks of the world are discretized to the hydrological units named unit-catchments for achieving efficient flow computation at the global scale. The water level and flooded area are diagnosed from the water storage at each unit-catchment using the sub-grid topographic parameters of the river channel and floodplains. The intended outputs are forecasted river discharge/inundation over the same time period. CaMa-Flood is a river routing scheme, that takes runoff components and precipitation over lakes and routes this to and through rivers. All runs compute river discharge using local inertia.

Data-specifics Hourly SST, sea ice, 10 and 100 windspeeds (sst, ci, 10si, 100si) in the IFS stream are only available from 2035 onwards for the scenario, and are present in the entire historical. For these 4 fields, missing value is 9999 and needs to be masked/set to “missing” in postprocessing. Scenario hourly SST can be retrieved for the full years from another variable, ‘stl1’ (soil temperature level 1), which reduces to SST over the ocean. The _ocean streams contain correct daily SST and ice cover data for the entire period. Hourly variable ‘2t’ (2m temperature) is called ‘mean2t’ in the monthly streams

ICON#

The ICON simulations use hierarchical HEALPix output. Please have a look at the introduction on Hierarchical HEALPix output for advice on data access.

TL;DR; Take ngc4008 for the run with the latest fixes and adjustments.

If you need a longer run, take ngc4006 (15 a) or ngc4008 (10 a, possibly extended;in progress)

For a quick look at results and output available, see

ngc4005 [1]:
ssp370 like scenario run from 2020
⚠ intermittent changes in output configuration
⚠ at model date 2024-04-01, sea-ice parameters were adjusted to yield more summer sea ice
⚠ contains a bug in the land surface energy balance
ngc4006 [2]
continues ngc4005 until 2040, finalized output configuration. Same caveats apply
ngc4007 [3]
restart ssp370-like scenario run from 2020. Includes bug fix for land energy balance, and a modification of the cloud liquid inhomogeneity factor to account for boundary layer clouds. Starts with the 2020 initial conditions like ngc4005, but the hydrological discharge model was re-adjusted using data from model year 2030 of ngc4006
ngc4008 [4]
as ngc4007, but slightly retuned inhomogeneity factor
Severe issues in the sea ice cover (esp. visible in late 2025).
ngc3542
somewhere between cycle3 and pre-final
includes HAMOCC for ocean biogeochemistry
Output on the native grid

References:

Yamazaki, D., S. Kanae, H. Kim, and T. Oki (2011), A physically-based description of floodplain inundation dynamics in a global river routing model. Water Resour. Res. 47, W04501, doi:10.1029/2010WR009726.

Yamazaki, D., G. A. M. de Almeida, and P. D. Bates (2013), Improving computational efficiency in global river models by implementing the local inertial flow equation and a vector-based river network map, Water Resources Research, published online.

Yamazaki, D., T. Sato, S. Kanae, Y. Hirabayashi, and P. D. Bates (2014a), Regional fl ood dynamics in a bifurcating mega delta simulated in a global river model, Geophys. Res. Lett., 41, doi:10.1002/2014GL059744.