Comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the Larsen C Ice Shelf, Antarctic Peninsula using the Met Office Unified Model (MetUM)
A foehn event on 27 January 2011 over the Larsen C Ice Shelf (LCIS), Antarctic Peninsula and its interaction with an exisiting ground-based cold-air pool is simulated using the MetUM atmospheric model at kilometre and sub-kilometre scale grid spacing. Atmospheric model simulations at kilometre grid...
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ftleedsuniv:oai:eprints.whiterose.ac.uk:177386 2023-05-15T13:37:09+02:00 Comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the Larsen C Ice Shelf, Antarctic Peninsula using the Met Office Unified Model (MetUM) Orr, A Kirchgaessner, A King, J Phillips, T Gilbert, E Elvidge, A Weeks, M Gadian, A Kuipers Munneke, P Broeke, M Webster, S McGrath, D 2021-07-26 text https://eprints.whiterose.ac.uk/177386/ https://eprints.whiterose.ac.uk/177386/1/2021-orr-qj.4138.pdf en eng Wiley https://eprints.whiterose.ac.uk/177386/1/2021-orr-qj.4138.pdf Orr, A, Kirchgaessner, A, King, J et al. (9 more authors) (2021) Comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the Larsen C Ice Shelf, Antarctic Peninsula using the Met Office Unified Model (MetUM). Quarterly Journal of the Royal Meteorological Society, 147 (739). pp. 3472-3492. ISSN 0035-9009 cc_by_4 CC-BY Article NonPeerReviewed 2021 ftleedsuniv 2023-01-30T22:40:42Z A foehn event on 27 January 2011 over the Larsen C Ice Shelf (LCIS), Antarctic Peninsula and its interaction with an exisiting ground-based cold-air pool is simulated using the MetUM atmospheric model at kilometre and sub-kilometre scale grid spacing. Atmospheric model simulations at kilometre grid scales are an important tool for understanding the detailed circulation and temperature structure over the LCIS, especially the occurrence of foehn-induced surface melting, erosion of cold-air pools, and low-level wind jets (so-called foehn jets). But whether there is an improvement/convergence in the model representation of these features at sub-kilometre grid scales has yet to be established. The foehn event was simulated at grid spacings of 4, 1.5 and 0.5 km, with the results compared to automatic weather station and radiosonde measurements. The features commonly associated with foehn, such as a leeside hydraulic jump and enhanced leeside warming, were comparatively insensitive to resolution in the 4 to 0.5 km range, although the 0.5 km simulation shows a slightly sharper and larger hydraulic jump. By contrast, during the event the simulation of fine-scale foehn jets above the cold-air pool showed considerable dependence on grid spacing, although no evidence of convergence at higher resolution. During the foehn event, the MetUM model is characterised by a nocturnal cold bias of around 8 °C and an underestimate of the near-surface stability of the cold-air pool, neither of which improved with increased resolution. This finding identifies a key model limitation, at both kilometre and sub-kilometre scales, to realistically capture the vertical mixing in the boundary layer and its impact on thermodynamics, through either daytime heating from below or the downward penetration of foehn jet winds from above. Detailed model-resolved foehn jet dynamics thus plays a crucial role in controlling the near-surface temperature structure over the LCIS, as well as sub-grid turbulent mixing. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Ice Shelf White Rose Research Online (Universities of Leeds, Sheffield & York) Antarctic Antarctic Peninsula |
institution |
Open Polar |
collection |
White Rose Research Online (Universities of Leeds, Sheffield & York) |
op_collection_id |
ftleedsuniv |
language |
English |
description |
A foehn event on 27 January 2011 over the Larsen C Ice Shelf (LCIS), Antarctic Peninsula and its interaction with an exisiting ground-based cold-air pool is simulated using the MetUM atmospheric model at kilometre and sub-kilometre scale grid spacing. Atmospheric model simulations at kilometre grid scales are an important tool for understanding the detailed circulation and temperature structure over the LCIS, especially the occurrence of foehn-induced surface melting, erosion of cold-air pools, and low-level wind jets (so-called foehn jets). But whether there is an improvement/convergence in the model representation of these features at sub-kilometre grid scales has yet to be established. The foehn event was simulated at grid spacings of 4, 1.5 and 0.5 km, with the results compared to automatic weather station and radiosonde measurements. The features commonly associated with foehn, such as a leeside hydraulic jump and enhanced leeside warming, were comparatively insensitive to resolution in the 4 to 0.5 km range, although the 0.5 km simulation shows a slightly sharper and larger hydraulic jump. By contrast, during the event the simulation of fine-scale foehn jets above the cold-air pool showed considerable dependence on grid spacing, although no evidence of convergence at higher resolution. During the foehn event, the MetUM model is characterised by a nocturnal cold bias of around 8 °C and an underestimate of the near-surface stability of the cold-air pool, neither of which improved with increased resolution. This finding identifies a key model limitation, at both kilometre and sub-kilometre scales, to realistically capture the vertical mixing in the boundary layer and its impact on thermodynamics, through either daytime heating from below or the downward penetration of foehn jet winds from above. Detailed model-resolved foehn jet dynamics thus plays a crucial role in controlling the near-surface temperature structure over the LCIS, as well as sub-grid turbulent mixing. |
format |
Article in Journal/Newspaper |
author |
Orr, A Kirchgaessner, A King, J Phillips, T Gilbert, E Elvidge, A Weeks, M Gadian, A Kuipers Munneke, P Broeke, M Webster, S McGrath, D |
spellingShingle |
Orr, A Kirchgaessner, A King, J Phillips, T Gilbert, E Elvidge, A Weeks, M Gadian, A Kuipers Munneke, P Broeke, M Webster, S McGrath, D Comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the Larsen C Ice Shelf, Antarctic Peninsula using the Met Office Unified Model (MetUM) |
author_facet |
Orr, A Kirchgaessner, A King, J Phillips, T Gilbert, E Elvidge, A Weeks, M Gadian, A Kuipers Munneke, P Broeke, M Webster, S McGrath, D |
author_sort |
Orr, A |
title |
Comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the Larsen C Ice Shelf, Antarctic Peninsula using the Met Office Unified Model (MetUM) |
title_short |
Comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the Larsen C Ice Shelf, Antarctic Peninsula using the Met Office Unified Model (MetUM) |
title_full |
Comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the Larsen C Ice Shelf, Antarctic Peninsula using the Met Office Unified Model (MetUM) |
title_fullStr |
Comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the Larsen C Ice Shelf, Antarctic Peninsula using the Met Office Unified Model (MetUM) |
title_full_unstemmed |
Comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the Larsen C Ice Shelf, Antarctic Peninsula using the Met Office Unified Model (MetUM) |
title_sort |
comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the larsen c ice shelf, antarctic peninsula using the met office unified model (metum) |
publisher |
Wiley |
publishDate |
2021 |
url |
https://eprints.whiterose.ac.uk/177386/ https://eprints.whiterose.ac.uk/177386/1/2021-orr-qj.4138.pdf |
geographic |
Antarctic Antarctic Peninsula |
geographic_facet |
Antarctic Antarctic Peninsula |
genre |
Antarc* Antarctic Antarctic Peninsula Ice Shelf |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Ice Shelf |
op_relation |
https://eprints.whiterose.ac.uk/177386/1/2021-orr-qj.4138.pdf Orr, A, Kirchgaessner, A, King, J et al. (9 more authors) (2021) Comparison of kilometre and sub-kilometre scale simulations of a foehn wind event over the Larsen C Ice Shelf, Antarctic Peninsula using the Met Office Unified Model (MetUM). Quarterly Journal of the Royal Meteorological Society, 147 (739). pp. 3472-3492. ISSN 0035-9009 |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
_version_ |
1766088661715124224 |