Surface air pressure is one of the most important parameters used in Numerical Weather Prediction (NWP) models. Although it has been measured using weather stations on the ground for many decades, the numbers of measurements are sparse and concentrated on land. Few measurements from buoys and ships are available over ocean. Global measurements can only be achieved by using remote sensing from Space, which is challenging; however, a novel design using Differential Absorption Radar (DAR) can provide a potential solution. The technique relies on two facts: first the electromagnetic fields are absorbed mainly by oxygen and water vapor, and second that oxygen is well mixed. In this work we discuss a space-borne concept, which aims at providing, over the ocean, consistent, and regular observations for determining surface air pressure from space by a design of a multi-tone radar operating on the upper wing of the O₂ absorption band with tones from 64 to 70 GHz. Simulations of radar vertical profiles based on the output of a state of-the-art microphysical retrievals applied to the A-Train suite of sensors are exploited to establish the performance of such a system for surface pressure determination. In particular the identification and quantification of errors introduced by the presence of water vapor, cloud liquid water and rain water and the potential of a correction via the three-tone method is discussed. Errors introduced by surface measurement noise and temperature profile uncertainties are discussed as well. Results show that accuracy between 2 and 5 hPa is at reach.

中文翻译：

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使用 60 GHz 氧气波段右翼的差分吸收雷达从太空进行表面气压测量

地面气压是数值天气预报 (NWP) 模型中使用的最重要参数之一。尽管数十年来一直使用地面气象站进行测量，但测量数量很少且集中在陆地上。海上浮标和船只的测量数据很少。全球测量只能通过太空遥感来实现，这具有挑战性；然而，使用差分吸收雷达（DAR）的新颖设计可以提供潜在的解决方案。该技术依赖于两个事实：首先电磁场主要被氧气和水蒸气吸收，其次氧气充分混合。在这项工作中，我们讨论了一个星载概念，其目的是通过在 O ₂上机翼上运行的多音雷达设计，在海洋上空提供一致和定期的观测，以确定来自太空的表面气压。吸收带的音调范围为 64 至 70 GHz。基于应用于 A-Train 传感器套件的最先进的微物理检索输出的雷达垂直剖面模拟被用来确定这种表面压力测定系统的性能。特别讨论了由水蒸气、云液态水和雨水的存在引起的误差的识别和量化以及通过三色调方法进行校正的潜力。还讨论了由表面测量噪声和温度分布不确定性引入的误差。结果表明，2 至 5 hPa 的精度已达到。