论文标题
潮汐锁定的水载体的模拟气候对模型分辨率的微小灵敏度
Small Sensitivity of the Simulated Climate of Tidally Locked Aquaplanets to Model Resolution
论文作者
论文摘要
在低质量恒星周围潮汐锁定的陆地行星是寻找潜在可居住的系外星球的主要目标。已经采用了几种大气一般循环模型来模拟其可能的气候，但是，模型间的模型表明，即使模型的结果在相同的边界条件下被迫，模型的结果也存在很大差异。在本文中，我们检查模型分辨率是否有助于差异。使用大气一般循环模型偶联与50米的平板海洋，我们检查了三种不同的水平分辨率（440 km * 550 km，210 km * 280 km * 280 km和50 km * 70 km * 70 km的纬度和垂直分辨率）和三种不同的垂直分辨率（26、51，51，和74级）（在相同的动力学核心和相同的动力学核心下）。在实验中，在全球均值的表面温度中，差异在5 K之内，行星反照率为0.007。这些差异来自云反馈，水蒸气反馈以及随着分辨率的增加而相对湿度的下降趋势。在替代区域上升柱之间的相对较小的下水道可以更好地解析，并且随着分辨率的增加，干燥和湿的空气包裹之间的混合以及砧云之间的混合会增强。这些降低了大气相对湿度和高级云部分，从而导致较低的透明温室效应，较弱的云长波辐射效应，并随后较酷的气候随着模型分辨率而增加。总体而言，潮汐锁定的水载体对模型分辨率的模拟气候的灵敏度很小。
Tidally locked terrestrial planets around low-mass stars are the prime targets of finding potentially habitable exoplanets. Several atmospheric general circulation models have been employed to simulate their possible climates, however, model intercomparisons showed that there are large differences in the results of the models even when they are forced with the same boundary conditions. In this paper, we examine whether model resolution contributes to the differences. Using the atmospheric general circulation model ExoCAM coupled to a 50-m slab ocean, we examine three different horizontal resolutions (440 km * 550 km, 210 km * 280 km, and 50 km * 70 km in latitude and longitude) and three different vertical resolutions (26, 51, and 74 levels) under the same dynamical core and the same schemes of radiation, convection and clouds. Among the experiments, the differences are within 5 K in global-mean surface temperature and within 0.007 in planetary albedo. These differences are from cloud feedback, water vapor feedback, and the decreasing trend of relative humidity with increasing resolution. Relatively small-scale downdrafts between upwelling columns over the substellar region are better resolved and the mixing between dry and wet air parcels and between anvil clouds and their environment are enhanced as the resolution is increased. These reduce atmospheric relative humidity and high-level cloud fraction, causing a lower clear-sky greenhouse effect, a weaker cloud longwave radiation effect, and subsequently a cooler climate with increasing model resolution. Overall, the sensitivity of the simulated climate of tidally locked aquaplanets to model resolution is small.
