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FutureWeather
This page provides details of the MetUM-GOML coupled model framework used in the Future Weather Project and the simulations that have been carried out within the project (summarised in table below).
The coupled modelling framework described here comprises the UK Met Office Unified Model (MetUM, version 7.8 in the fixed scientific configuration GA3.0) coupled to the Multi-Column K Profile Parameterization (MC-KPP) mixed-layer ocean model with 3-hourly exchanges via the OASIS coupler (version 3.2.5). MC-KPP does not (yet) have interactive sea ice, therefore, the latitudinal extent of the coupling domain is determined taking into account regions of seasonally-varying sea ice; coupling is not applied at points which had 30 days/year of ice for at least 3 years of a 30-year climatology. Outside the coupled region the MetUM is forced by daily climatological SSTs and ice from the Met Office Ocean analysis, with a linear blend at the boundary: at N96 (n216) the blend is over 5 (12) gridpoints.
MC-KPP is parameterized using the KPP scheme of Large et al. 1994. KPP includes a scheme for determining the mixed-layer depth by parameterizing the turbulent contributions to the vertical shear of a bulk Richardson number. A nonlocal vertical diffusion scheme is used to represent the transports of heat and salt by eddies with a vertical scale equivalent to that mixed-layer depth.
The effective horizontal resolution of MC-KPP is the same as the atmospheric model to which it is coupled (e.g. N96 or N216 in the simulations in the table below). MC-KPP is configured with a depth of 1000m over 100 vertical levels. The vertical discretization of MC-KPP is defined using a stretch function over the first 72 levels to maintain high near-surface resolution. At the surface the resolution of MC-KPP is 1.2m, less than 2m over the first 41.5m and less than 5m to a depth of 127.8m. Below 287.2m the remaining levels are equally spaced every 25m. Bathymetry is defined using the ETOPO2 Global Relief Model from NOAA, where the ocean depth is < 1000m, MC-KPP is prevented from computing a mixed-layer depth greater than the ocean depth.
Since MC-KPP does not represent any ocean dynamics, depth-varying temperature and salinity corrections are required to represent the mean ocean advection and account for biases in atmospheric surface fluxes. The corrections are computed from a 10-year simulation in which 3D profiles of oceanic temperature and salinity in MetUM-GOML are constrained to a reference climatology (Met Office ocean analysis) over a 15-day relaxation timescale. The daily mean seasonal cycle of temperature and salinity corrections from the constrained MetUM-GOML simulation are then imposed in 'free-running' simulations with no interactive relaxation.
The strongly constrained flux correction simulations:
| Experiment ID | UMUI runid | Coupled?, SSTs | Horizontal resolution | Details | Run length (yrs) |
|---|---|---|---|---|---|
| K-O-RLX-N96 | xilah | Yes | N96 (~135 km) | 15-day interactive relaxation on T and S towards observations (Met Office Ocean analysis; Smith and Murphey 2007) | 10 |
| K-O-RLX-N216 | xjhwa | Yes | N216 (~60km) | 15-day interactive relaxation on T and S towards observations (Met Office Ocean analysis; Smith and Murphey 2007) | 10 |
This page describes coupling MC-KPP1.0 to the MetUM (version 7.8, GA3.0), further information on other configurations can be found on the Supported Models page.
The table below details the Future Weather Simulations. All coupled simulations described here use the near globally coupled MetUM-GOML framework described above.
| Experiment ID | UMUI runid | Coupled?, SSTs | Horizontal resolution | Initialised 1st Jan | Run length (yrs) |
|---|---|---|---|---|---|
| K-O-E1-N96 | xilai | Yes | N96 | Year 10 of K-O-RLX-N96 | 45 |
| K-O-E2-N96 | xilaj | Yes | N96 | Year 9 of K-O-RLX-N96 | 25 |
| K-O-E3-N96 | xilak | Yes | N96 | Year 8 of K-O-RLX-N96 | 25 |
| A-K31-E1-N96 | xilas | No, 31-day smoothed SSTs from K-O-E1-N96 | N96 | Year 10 of K-O-RLX-N96 | 45 |
| A-K31-E2-N96 | xilat | No, 31-day smoothed SSTs from K-O-E2-N96 | N96 | Year 9 of K-O-RLX-N96 | 25 |
| A-K31-E3-N96 | xilau | No, 31-day smoothed SSTs from K-O-E3-N96 | N96 | Year 8 of K-O-RLX-N96 | 25 |
| A-Kcl-E1-N96 | xilap | No, mean seasonal cycle of SSTs from K-O-E1-N96 | N96 | Year 10 of K-O-RLX-N96 | 45 |
| A-Kcl-E2-N96 | xilaq | No, mean seasonal cycle of SSTs from K-O-E2-N96 | N96 | Year 9 of K-O-RLX-N96 | 25 |
| A-Kcl-E3-N96 | xilar | No, mean seasonal cycle of SSTs from K-O-E3-N96 | N96 | Year 8 of K-O-RLX-N96 | 25 |
| K-O-E1-N216 | xjhwb | Yes | N216 | Year 10 of K-O-RLX-N216 | 22 |
| K-O-E2-N216 | xjhwc | Yes | N216 | Year 9 of K-O-RLX-N216 | 22 |
| K-O-E3-N216 | xjhwd | Yes | N216 | Year 8 of K-O-RLX-N216 | 22 |
| A-K31-E1-N216 | xjhwe | No, 31-day smoothed SSTs from K-O-E1-N216 | N216 | Year 10 of K-O-RLX-N216 | 22 |
| A-K31-E2-N216 | xjhwf | No, 31-day smoothed SSTs from K-O-E2-N216 | N216 | Year 9 of K-O-RLX-N216 | 22 |
| A-K31-E3-N216 | xjhwg | No, 31-day smoothed SSTs from K-O-E3-N216 | N216 | Year 8 of K-O-RLX-N216 | 22 |
| A-Kcl-E1-N216 | xjhwh | No, mean seasonal cycle of SSTs from K-O-E1-N216 | N216 | Year 10 of K-O-RLX-N216 | 22 |
| A-Kcl-E2-N216 | xjhwi | No, mean seasonal cycle of SSTs from K-O-E2-N216 | N216 | Year 9 of K-O-RLX-N216 | 22 |
| A-Kcl-E3-N216 | xjhwj | No, mean seasonal cycle of SSTs from K-O-E3-N216 | N216 | Year 8 of K-O-RLX-N216 | 22 |