sws (b1)

The shortwave spectroradiometer (SWS) measures the absolute visible and near-infrared spectral radiance (units of watts per square meter per nanometer per steradian) of the zenith directly above the instrument. The SWS is a moderate-resolution sensor comprised of two Zeiss spectroradiometers (MMS 1 NIR enhanced and NIR-PGS 2.2) for visible and near-infrared detection in the wavelength range 350-2170 nm. The sampling frequency is 1 Hz. The spectral resolution is 8 nm for the MMS 1 NIR and 12 nm for the NIR-PGS 2.2. The light collector has a narrow-field-of-view (1.4°) collimator at the front end of a high-grade, custom-made fiber-optic bundle. The SWS does daily daytime measurements. At the Southern Great Plains site, the SWS is located in a darkroom within the optical trailer to permit calibrations to be conducted without moving the instrument. Calibrations are performed on schedule using the ARM 12" integrating sphere. SWS measurements can be used to: 1. Retrieve cloud optical depth, particle size, and water path. 2. Test the cloud optical depth retrieval for overcast and broken cloud fields. 3. Validate/compare with SGP surface remote sensors and future cloud IOP campaigns. 4. Perform multivariate analysis to derive information content in hyper-spectral data sets and improve cloud retrieval algorithm development. 5. Compare with radiative transfer models for testing and validating retrieval procedures.短波光谱辐射计（Shortwave Spectroradiometer，SWS）可测量仪器正上方天顶方向的绝对可见-近红外光谱辐亮度，单位为瓦每平方米每纳米每球面度。 该SWS属于中分辨率传感器，由两台蔡司（Zeiss）光谱辐射计组成，分别为MMS 1 NIR增强型与NIR-PGS 2.2型，用于350~2170 nm波长范围内的可见及近红外探测。其采样频率为1赫兹，MMS 1 NIR增强型的光谱分辨率为8 nm，NIR-PGS 2.2型的光谱分辨率为12 nm。 该设备的光收集系统在定制高级光纤束的前端配备了窄视场（1.4°）准直器。 SWS每日开展日间测量。 在南大平原（Southern Great Plains，SGP）站点，SWS被安置于光学拖车内的暗室中，以便无需移动仪器即可开展校准工作。 校准工作将按照预定计划，使用ARM 12英寸积分球实施。 SWS的测量数据可用于以下场景：1. 反演云光学厚度、粒子粒径及水路径；2. 针对阴天及破碎云场开展云光学厚度反演的验证工作；3. 与SGP地面遥感传感器及未来云密集观测期（IOP）试验进行比对验证；4. 开展多变量分析，以挖掘高光谱数据集的信息含量并优化云反演算法的研发；5. 与辐射传输模型开展比对，以测试并验证反演流程。