Abstract:
High-resolution hindcasts (1979-2019) of summer climate over Antarctica using the UK Met Office Unified Model (MetUM) and HIRHAM5 were conducted at the British Antarctic Survey and Danish Meteorological Institute, respectively. The hindcasts are conducted for summer 1979-2018, i.e., from December 1979 to February 2019, for December, January, February (DJF). This dataset consists of near-surface temperature output from these hindcasts at a temporal resolution of every 3 hrs. The hindcasts are contributions to the COordinated Regional Downscaling EXperiment (CORDEX) project. Both models are run over Antarctic CORDEX domains, which encompass all of Antarctica and some of the surrounding ocean, at a horizontal grid spacing of around 12 km. The near-surface temperatures are used to estimate regional surface melt "potential" over Antarctic ice shelves as a function of summertime temperature extremes and identify regions of potentially enhanced "hotspots" of melt potential based on the occurrence (and magnitude) of various temperatures.
Funding was provided by the European Union's Horizon 2020 research and innovation framework programme under Grant agreement no. 101003590 (PolarRES)
Keywords:
HIRHAM5, MetUM, Polar CORDEX, high-resolution atmospheric modelling, hindcast
Orr, A., Boberg, F., & Phillips, T. (2022). MetUM and HIRHAM5 simulations of summer near-surface temperatures over Antarctica from 1979 to 2019 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/05f8bd4b-97b1-43d0-a1c6-66aea7021aaf
| Access Constraints: | None |
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| Use Constraints: | Data supplied under Open Government Licence v3.0 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. |
| Creation Date: | 2022-09-07 |
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| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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| Personnel: | |
| Name | UK PDC |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Andrew Orr |
| Role(s) | Investigator, Technical Contact |
| Organisation | British Antarctic Survey |
| Name | Fredrik Boberg |
| Role(s) | Investigator |
| Organisation | Danish Meteorological Institute |
| Name | Tony Phillips |
| Role(s) | Technical Contact |
| Organisation | British Antarctic Survey |
| Parent Dataset: | N/A |
| Reference: | Orr, A., P. Deb, K. Clem, E. Gilbert, F. Boberg, D. Bromwich, S. Colwell, N. Hansen, M. Lazzara, P. Mooney, R. Mottram, M. Niwano, T. Phillips, D. Pishniak, C. Reijmer, W. J. van de Berg, Stuart Webster, and X. Zou, Summer air temperature extremes over Antarctic ice shelves and potential "hotspots" of surface melting, Journal of Climate, in press. | |
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| Quality: | Summer daily maximum temperatures derived from both the MetUM and HIRHAM5 hindcasts were compared in a statistical analysis with observations from twenty weather stations situated either on or close to Antarctic ice shelves. This comparison showed that the MetUM simulated temperatures were characterised by a) a cold bias for fifteen out of the twenty stations, which for ten of the stations was less than 1 K, b) a root-mean-square-error of 2-3 K, and c) a correlation from 0.62-0.91. The HIRHAM5 summer daily maximum temperatures typically have a larger cold bias, larger root-mean-square-error, and lower correlation than the MetUM results. The relatively good performance of the MetUM (and to a lesser extent HIRHAM5) suggests that daily maximum temperatures over Antarctic ice shelves derived from these model outputs are broadly representative of actual conditions. | |
| Lineage: | The UK Met Office Unified Model (known as MetUM) uses the GA6 (Global Atmosphere 6.0; Walters et al., 2017) configuration of version 11.1, which is suitable for grid scales of 10 km or coarser. The HIRHAM5 model combines the physics of the ECHAM5 general circulation model and the hydrostatic dynamical core of the HIRLAM7 numerical weather prediction model (Christensen et al., 2007). The MetUM (HIRHAM5) uses 70 (31) vertical levels in the atmosphere. The ice mask used by both models is derived from Advanced Very High-Resolution Radiometer (AVHRR) data from the period 1992 to 1993 at a resolution of 1 km. Both models are run over Antarctic CORDEX domains from December 1979 to February 2019 at grid spacing of around 12 km, with the MetUM (HIRHAM5) grid consisting of 392 x 504 (406 x 542) grid points. Initial and boundary conditions for both models are supplied by ERA-Interim reanalysis data. The MetUM hindcast uses a frequent re-initialization approach, consisting of twice-daily 24 hr forecasts. Output at T+12, T+15, T+18, and T+21 hr from each of the forecasts is concatenated together to form a seamless series of 3-hourly model outputs, with the earlier output discarded as spin-up. The HIRHAM5 hindcast uses a long-term continuous integration approach, with no nudging. Christensen, O. B., M. Drews, J. H. Christensen, K. Dethloff, K. Ketelsen, I. Hebestadt, and A. Rinke, 2007: The HIRHAM regional climate model, Version 5 (beta), Danish Climate Centre, Danish Meteorological Institute, Danish Meteorological Institute, Technical Report. ISSN 1399-1388 Walters, D., I. Boutle, M. Brooks, T. Melvin, R. Stratton, S. Vosper, H. Wells, K. Williams, N. Wood, T. Allen, A. Bushell, D. Copsey, P. Earnshaw, J. Edwards, M. Gross, S. Hardiman, C. Harris, J. Heming, N. Klingaman, R. Levine, J. Manners, G. Martin, S. Milton, M. Mittermaier, C. Morcrette, T. Riddick, M. Roberts, C. Sanchez, P. Selwood, A. Stirling, C. Smith, D. Suri, W. Tennant, P. L. Vidale, J. Wilkinson, M. Willett, S. Woolnough, and P. Xavier, 2017: The Met Office Unified Model Global Atmosphere 6.0/6.1 and JULES Global Land 6.0/6.1 configurations. Geosci. Model. Dev., 10, 1487-1520, https://doi.org/10.5194/gmd-10-1487-2017. |
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| Temporal Coverage: | |
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| Start Date | 1979-12-01 |
| End Date | 2019-02-28 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -68.245 |
| Northernmost | -53.374 |
| Longitude | |
| Westernmost | -180 |
| Easternmost | 180 |
| Altitude | |
| Min Altitude | 2m |
| Max Altitude | 2m |
| Depth | |
| Min Depth | N/A |
| Max Depth | N/A |
| Latitude | |
| Southernmost | -68.96 |
| Northernmost | -55.141 |
| Longitude | |
| Westernmost | -180 |
| Easternmost | 180 |
| Altitude | |
| Min Altitude | 1.5m |
| Max Altitude | 1.5m |
| Depth | |
| Min Depth | N/A |
| Max Depth | N/A |
| Data Resolution: | |
| Latitude Resolution | 0.11 degrees (~12 km) |
| Longitude Resolution | 0.11 degrees (~12 km) |
| Horizontal Resolution Range | N/A |
| Vertical Resolution | N/A |
| Vertical Resolution Range | N/A |
| Temporal Resolution | N/A |
| Temporal Resolution Range | N/A |
| Location: | |
| Location | Antarctica |
| Detailed Location | N/A |
| Distribution: | |
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| Distribution Media | Online Internet (HTTP) |
| Distribution Size | 14 GB |
| Distribution Format | netCDF |
| Fees | N/A |
| Data Storage: | The data are held as CF-compliant netCDF files, structured so that each netCDF file contains data for one model for one month. For each model this data set contains 120 files (one for each of December, January and February for 40 summers). In addition to near-surface temperature data with CF-compliant spatiotemporal coordinates (on the relevant rotated latitude-longitude coordinate system), each netCDF file also contains auxiliary coordinates giving the true latitude and longitude coordinates for each point in the grid. The HIRHAM5 data files are held in the "HIRHAM5" directory and are named: DMI-HIRHAM5_AT6_Near-Surface_Air_Temperature_[YYYYMM].nc (where YYYY identifies the year and MM is the 2-digit month number). The total size of the HIRHAM5 data is 6450 MB. The MetUM data files are held in the "MetUM" directory and are named: Antarctic_CORDEX_MetUM_0p11deg_3-hourly_air_temperature_at_1.5_m_[YYYYMM].nc (where YYYY identifies the year and MM is the 2-digit month number). The total size of the MetUM data is 7537 MB. |