The Infrared Radiative Impact of Antarctic Clouds

尽管它们对辐射传输很重要，但极地云中过冷液态水的数量可能是不确定的。这种低估反过来又导致了地面和TOA（大气层顶部）的显著辐射偏差以及极地气溶胶-云相互作用的错误描述。最近的工作涉及调整气候模式，使混合相云分布与观测结果相匹配，结果增加了南极上空的净云辐射效应。因此，了解南极气候的一个关键组成部分是更准确地表示云中过冷液体的丰度以及相应的云-辐射相互作用。大气辐射干涉仪南极站的AERI）-（2000年），圆顶C -（2003年），将在麦默多站建造（计划于2015年11月至2016年11月）将用于评估云特性的季节依赖性和云对当地地表辐射收支的影响。本文提出了两个假设：1）南极辐射收支对云的性质，特别是热力学相的变化非常敏感; 2）水的复折射率（CRI）的温度依赖性对南极云中过冷液体的辐射影响有显著影响。

Despite their importance to radiative transfer, the amount of supercooled liquid water in polar clouds may be uncertain. This underestimation in turn results in significant radiation biases at the surface and TOA (top of the atmosphere) and misrepresentation of polar aerosol-cloud interactions. Recent work involving tuning a climate model to match mixed phase cloud distributions with observations resulted in an increase in net cloud radiative effects over Antarctica. A crucial component of understanding Antarctic climate, therefore, is a more accurate representation of the abundance of supercooled liquid in clouds and of corresponding cloud-radiative interactions.Leveraging down-welling radiance measurement data previously collected with FT-IR instruments (Atmospheric Emitted Radiance Interferometers; AERIs) at South Pole Station - (2000) , Dome C - (2003) and to be made at McMurdo Station (planned for Nov. 2015-Nov. 2016) will be used to assess the seasonal dependence of cloud properties and cloud impacts on the local surface radiative budget. Two hypotheses will be considered:1) The Antarctic radiation budget is highly sensitive to cloud properties, particularly thermodynamic phase.2) The radiative impact of supercooled liquid in Antarctic clouds is significantly influenced by the temperature dependence of the complex refractive index of water (CRI)