Verification of the regional atmospheric model CCLM v5.0 with conventional data and lidar measurements in Antarctica
<p>The nonhydrostatic regional climate model CCLM was used for a long-term hindcast run (2002–2016) for the Weddell Sea region with resolutions of 15 and 5 <span class="inline-formula">km</span> and two different turbulence parametrizations. CCLM was nested in...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-04-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://www.geosci-model-dev.net/13/1809/2020/gmd-13-1809-2020.pdf |
| Summary: | <p>The nonhydrostatic regional climate model CCLM was used for
a long-term hindcast run (2002–2016) for the Weddell Sea region with
resolutions of 15 and 5 <span class="inline-formula">km</span> and two different turbulence
parametrizations. CCLM was nested in ERA-Interim data and used in
forecast mode (suite of consecutive 30 <span class="inline-formula">h</span> long simulations with
6 <span class="inline-formula">h</span> spin-up). We prescribed the sea ice concentration from
satellite data and used a thermodynamic sea ice model. The
performance of the model was evaluated in terms of temperature and
wind using data from Antarctic stations, automatic weather stations (AWSs), an
operational forecast model and reanalyses data, and lidar wind
profiles. For the reference run we found a warm bias for the
near-surface temperature over the Antarctic Plateau. This bias was
removed in the second run by adjusting the turbulence parametrization,
which results in a more realistic representation of the surface
inversion over the plateau but resulted in a negative bias for some
coastal regions. A comparison with measurements over the sea ice of
the Weddell Sea by three AWS buoys for 1 year showed small biases
for temperature around <span class="inline-formula">±1</span> <span class="inline-formula">K</span> and for wind speed of
1 <span class="inline-formula">m s<sup>−1</sup></span>. Comparisons of radio soundings showed a model bias
around 0 and a RMSE of 1–2 <span class="inline-formula">K</span> for temperature and
3–4 <span class="inline-formula">m s<sup>−1</sup></span> for wind speed. The comparison of CCLM
simulations at resolutions down to 1 <span class="inline-formula">km</span> with wind data from
Doppler lidar measurements during December 2015 and January 2016
yielded almost no bias in wind speed and a RMSE of ca. 2 <span class="inline-formula">m s<sup>−1</sup></span>. Overall CCLM shows a good representation of temperature and
wind for the Weddell Sea region. Based on these encouraging results,
CCLM at high resolution will be used for the investigation of the
regional climate in the Antarctic and atmosphere–ice–ocean
interactions processes in a forthcoming study.</p> |
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| ISSN: | 1991-959X 1991-9603 |