Modelling the climate and surface mass balance of polar ice sheets using RACMO2 – Part 2: Antarctica (1979–2016)
Modelling the climate and surface mass balance of polar ice sheets using RACMO2 – Part 2: Antarctica (1979–2016)
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DOI：
10.5194/tc-12-1479-2018
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发表时间：
2017-10
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通讯作者：
J. M. Wessem;W. J. Berg;B. Noël;E. Meijgaard;C. Amory;G. Birnbaum;C. L. Jakobs;Konstantin Krüger-Konstantin-Krüg
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作者：
J. M. Wessem;W. J. Berg;B. Noël;E. Meijgaard;C. Amory;G. Birnbaum;C. L. Jakobs;Konstantin Krüger-Konstantin-Krüg
抽象的。我们从极地版本的区域大气气候模式RACMO2(1979-2016)评估了模拟的南极冰盖(AIS)近地表气候、地表物质平衡(SMB)和地表能量平衡(SEB)。更新的模式被称为RACMO2.3p2，包括高空松弛，修正的地形，调整云图中的参数以产生更多向AIS内部的降水，以及改变雪的性质，减少漂移的雪升华和增加表面的积雪融化。RACMO2模式输出与几个独立观测资料的比较表明，与前一个模式版本相比，AIS温度、辐射通量和SMB分量的现有偏差进一步减小。包括冰架在内的冰盖(不包括南极半岛，AP)的模式综合年平均SMB现在达到2229GT y−1，年际变率为109GT y−1。最大的改进是模拟地表积雪融化，它现在可以与卫星和气象站的观测结果相媲美。对于高分辨率(∼5.5公里)AP模拟，结果仍然与先前的研究相当。更新的模型提供了当代近地表气候和AIS中小型企业的新的高分辨率数据集；该模型版本将在即将进行的一项研究中用于未来气候情景预测。
Abstract. We evaluate modelled Antarctic ice sheet (AIS) near-surface climate, surface mass balance (SMB) and surface energy balance (SEB) from the updated polar version of the regional atmospheric climate model, RACMO2 (1979–2016). The updated model, referred to as RACMO2.3p2, incorporates upper-air relaxation, a revised topography, tuned parameters in the cloud scheme to generate more precipitation towards the AIS interior and modified snow properties reducing drifting snow sublimation and increasing surface snowmelt. Comparisons of RACMO2 model output with several independent observational data show that the existing biases in AIS temperature, radiative fluxes and SMB components are further reduced with respect to the previous model version. The model-integrated annual average SMB for the ice sheet including ice shelves (minus the Antarctic Peninsula, AP) now amounts to 2229 Gt y −1 , with an interannual variability of 109 Gt y −1 . The largest improvement is found in modelled surface snowmelt, which now compares well with satellite and weather station observations. For the high-resolution ( ∼ 5.5 km) AP simulation, results remain comparable to earlier studies. The updated model provides a new, high-resolution data set of the contemporary near-surface climate and SMB of the AIS; this model version will be used for future climate scenario projections in a forthcoming study.