Infrared CIrrus CLoud Experiment (ICICLE).

高分辨率动力学和临边探测器（HIRDLS）是美国国家环境研究中心和美国航天局联合资助的一种仪器，它将以极高的垂直分辨率（约1公里）和空间分辨率（每天9000个剖面）在21个光谱通道中测量大气临边发射。在准备发射时，我们开发了蒙特卡罗云散射（McClouds）算法来检索卷云特性（冰晶有效半径，云顶高度和云光学深度）。这一方案的一个非常强有力的科学驱动力是推测卷云的性质被来自人类污染物的硝酸改变。这种硝酸效应的诱人证据已经在飞机研究中得到了，但还没有明确的全球观测结果将卷云特性与含氮气体的源区明确联系起来。该提案将资助从全球HIRDLS数据中检索卷云特性。MLS仪器对温度、水蒸气和硝酸的几乎同时测量将用于从温度和气体蒸气压力方面描述卷云的特征。

The High Resolution Dynamics and Limb Sounder (HIRDLS) is a joint NERC-NASA funded instrument which will measure atmospheric limb emission in 21 spectral channels at very high vertical (~1 km) and spatial resolution (9000 profiles per day). In preparation for launch we have developed the Monte Carlo Cloud Scattering (McClouds) algorithm to retrieve cirrus cloud properties (ice crystal effective radius, cloud top height and cloud optical depth). A very strong scientific driver for this programme is the speculation that cirrus cloud properties are modified by nitric acid originating from anthropogenic pollutants. Tantalizing evidence of this nitric acid effect has been made in aircraft studies but no definitive global observations have been made that would unambiguously relate cirrus properties to the source regions of nitrogen containing gases. This proposal will fund the retrieval of cirrus cloud properties from global HIRDLS data. Near simultaneous measurements of temperature, water vapour and nitric acid made by the MLS instrument will be used to characterize the cirrus clouds in terms of the temperature and gas vapour pressures.