Abstract:
High-resolution simulations of extreme warm temperature events over South Georgia Islands using the UK Met Office Unified Model (MetUM) were conducted at the British Antarctic Survey. The simulations are conducted for the period 1 to 17 January 1991, which included an event in which the temperature at Signy station peaked at 17.4 degrees Celsius on 13 January 1991, as well as a series of consecutive warm events preceding this. The dataset consists of 1) 10 m zonal wind, 10 m meridional wind, 1.5 m temperature, 1.5 m dew point temperature, 1.5 m relative humidity, and mean sea level pressure at a temporal resolution of every 1 hr for the period 1 to 17 January, 2) zonal wind, meridional wind, vertical wind, and potential temperature on model levels at 00UTC 13 January, and 3) rainfall rate at 00 UTC 13 January (averaged over a 3-hr period). The MetUM is run over a domain that includes South Orkney Islands and the surrounding ocean, which comprises 120 x 120 grid points at a grid spacing of 1 km. The model output is used to investigate the detailed influence of South Orkney Islands orography on temperature, precipitation, and winds, and in particular the importance of foehn events in producing extreme warm temperatures at Signy station.
Funding:
1) Core funding from the Natural Environment Research Council (NERC) to the Atmosphere, Ice and Climate Programme of British Antarctic Survey (BAS).
2) NERC National Capability International grant SURface FluxEs In AnTarctica (NE/X009319/1).
3) European Union's Horizon 2020 research and innovation framework programme under Grant agreement no. 101003590 (PolarRES).
Keywords:
MetUM, South Orkney Islands, extreme warm temperature events, fohn events, high-resolution atmospheric modelling
Orr, A., & Phillips, T. (2023). MetUM high-resolution simulations of extreme warm temperature events over South Orkney Islands from 1 to 17 January 1991 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/0b011472-c766-4190-8718-8cf4be95daa6
| Access Constraints: | No restrictions apply. |
|---|---|
| Use Constraints: | Data supplied under Open Government Licence v3.0 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. |
| Creation Date: | 2023-09-25 |
|---|---|
| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
|
| Parameters: |
|
| Personnel: | |
| Name | UK Polar Data Centre |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Andrew Orr |
| Role(s) | Investigator, Technical Contact |
| Organisation | British Antarctic Survey |
| Name | Tony Phillips |
| Role(s) | Technical Contact |
| Organisation | British Antarctic Survey |
| Parent Dataset: | N/A |
| Reference: | Lineage references: Bush, M., Allen, T., Bain, C., Boutle, I., Edwards, J., Finnenkoetter, A., Franklin, C., Hanley, K., Lean, H., Lock, A., Manners, J., Mittermaier, M., Morcrette, C., North, R., Petch, J., Short, C., Vosper, S., Walters, D., Webster, S., Weeks, M., Wilkinson, J., Wood, N. and Zerroukat, M. (2020). The first Met Office unified model-JULES regional atmosphere and land configuration, RAL1. Geoscientific Model Development, 13, 1999-2029, DOI: 10.5194/gmd-13-1999-2020. Associated publication: Lu, H., A. Orr, J. King, T. Phillips, E. Gilbert, S. Colwell, and T. Bracegirdle, Extreme warm events in the South Orkney Islands, Southern Ocean: Compounding influence of atmospheric rivers and fohn conditions, Q. J. Roy. Met. Soc., under review. |
|
|---|---|---|
| Lineage: | The UK Met Office Unified Model (known as MetUM) uses the Regional Atmosphere physics configuration for mid-latitudes (RA1M; Bush et al. 2020) configuration of version 13. The MetUM uses 70 vertical levels in the atmosphere. The MetUM model setup uses three (one-way) nested domains with horizontal grid spacings of 12, 4 and 1 km, comprising 100 x 100, 100 x 100, and 120 x 120 grid points, respectively. The innermost 1 km domain covers the South Orkney Islands and surrounding ocean, and uses orography derived from the 100 m resolution Radarsat Antarctic Mapping Project (RAMP) digital elevation model. Initial and boundary conditions for the outermost 12 km domain are supplied by a global version of the MetUM at N512 resolution (1024 x 768 grid points, equivalent to a horizontal resolution of ~25 km at midlatitudes), which is initialised with ERA5 data. The 12 km model is subsequently used to produce initial and boundary conditions for the 4 km model, which in turn produces initial and boundary conditions for the 1 km model. The model is run twice-daily at 00 and 12 UTC to produce a series of 24 h forecasts. The initial 12 h of each forecast is discarded as spin-up, with the remaining part of the forecasts concatenated together to form a continuous time series. | |
| Temporal Coverage: | |
|---|---|
| Start Date | 1991-01-01 |
| End Date | 1991-01-17 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -61.14 |
| Northernmost | -60.06 |
| Longitude | |
| Westernmost | -46.38 |
| Easternmost | -44.15 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | N/A |
| Max Depth | N/A |
| Data Resolution: | |
| Latitude Resolution | 1km |
| Longitude Resolution | 1km |
| Horizontal Resolution Range | N/A |
| Vertical Resolution | N/A |
| Vertical Resolution Range | N/A |
| Temporal Resolution | 1 hr, 3 hr |
| Temporal Resolution Range | Hourly - < Daily |
| Location: | |
| Location | N/A |
| Detailed Location | South Orkney Islands |
| Data Storage: | The data are stored as CF-compliant netCDF4 files, with one data variable stored per file. The files are named according to the pattern SOI_MetUM_0.009_degree_[standard name]_[description of level(s)]_[time coverage description].nc, where [standard name] is the CF standard name of the variable, [description of level(s)] is ''at_[height coordinate value]_[height coordinate units]'' for single-level variables, and ''on_model_levels'' for model level variables, and [time coverage description] is ''at_[time coordinate value]'' for instantaneous variables provided for one period, ''at_[time coordinate lower bound]_to_[time coordinate upper bound]'' for time-mean variables provided for one period, and ''at_[time coordinate earliest value]_to_[time coordinate latest value]'' for variables provided for more than one period. Time coordinate values are formatted as ISO-8601 date/times. Note that three variables (air_pressure_at_sea_level, land_binary_mask and surface_altitude) do not have a vertical coordinate. For these variables, the filename ''_[description of level(s)]'' component is omitted from the pattern. This data set contains a total of 17 files - 8 files of single-level instantaneous variables, 6 files of output on model levels, one file of 3-hourly mean output and two files of invariant data. The data are provided on the MetUM rotated grid horizontal coordinate system. For all variables, the true latitude and longitude coordinates are provided as auxiliary coordinate variables. The wind field components are provided both as grid-directed components (x_wind and y_wind) and as latitude- and longitude-directed components (northward_wind and eastward_wind). For all variables on model levels (which are hybrid heights), the data files include surface altitude as an auxiliary coordinate and CF-compliant metadata to allow software to derive the actual heights for all data points. The total size of this data set is 60 MB. |
|---|