Sounder SIPS: Suomi NPP CrIMSS Level 3 Specific Quality Control Gridded Daily CLIMCAPS Normal Spectral Resolution V2 (SNDRSNIML3SDCCPN) at GES DISC

The CLIMCAPS (Community Long-term Infrared Microwave Coupled Product System) algorithm is used to analyze data from the Cross-track Infrared Sounder/Advanced Technology Microwave Sounder (CrIS/ATMS) instruments, also known as CrIMSS (Cross-track Infrared and Microwave Sounding Suite). The CrIS/ATMS instruments used for this product are on board the Suomi National Polar-orbiting Partnership (SNPP) platform and use the Normal Spectral Resolution (NSR) data. The CrIS instrument is a Fourier transform spectrometer with a total of 1305 NSR infrared sounding channels covering the longwave (655-1095 cm-1), midwave (1210-1750 cm-1), and shortwave (2155-2550 cm-1) spectral regions. The ATMS instrument is a cross-track scanner with 22 channels in spectral bands from 23 GHz through 183 GHz.

The CLIMCAPS algorithm uses an Optimal Estimation methodology and uses an a-priori first guess to start the process. A CLIMCAPS sounding is comprised of a set of parameters that characterizes the full atmospheric state and includes a variety of geophysical parameters derived from the CrIMSS data. These include surface temperature and infrared emissivity; full atmosphere profiles of temperature, water vapor and ozone; infrared effective cloud top characteristics; carbon monoxide, methane, carbon dioxide, sulfur dioxide, nitrous oxide, and nitric acid.

This daily one degree latitude by one degree longitude level-3 product starts with level-2 retrieval products with QC values of 0 (best), 1 (good), and 2 (don't use) which are provided for each variable and applying specific QC methodology. Specific QC accepts profile level from the top of the atmosphere down to the level where the QC determines that it is still good. Below this level, the data is rejected.

WARNING: To users of the derived product “co_mmr_midtrop” (carbon monoxide mass mixing ratio to dry air [kg/kg] at ~500 hPa). This variable has a significant bias due to a conversion error: the molecular weight of carbon dioxide (CO2, 48.01 g/mol) was used instead of carbon monoxide (CO, 28.01 g/mol). To correct, simply multiply “co_mmr_midtrop” by 28.01/48.01. Alternatively, derive a profile of mass mixing ratio from scratch using the retrieved column density values (“mol_lay/co_mol_lay”) in the Level 2 files. For further questions or concerns please contact the Sounder SIPS at: [e-mail]

CLIMCAPS（Community Long-term Infrared Microwave Coupled Product System，社区长期红外微波耦合产品系统）算法用于分析跨轨红外探测器/先进技术微波探测器（Cross-track Infrared Sounder/Advanced Technology Microwave Sounder，CrIS/ATMS）仪器的数据，该仪器亦被称为CrIMSS（Cross-track Infrared and Microwave Sounding Suite，跨轨红外与微波探测套件）。本产品所使用的CrIS/ATMS仪器搭载于Suomi国家极轨合作（Suomi National Polar-orbiting Partnership，SNPP）平台，采用标准光谱分辨率（Normal Spectral Resolution，NSR）数据。其中CrIS仪器为傅里叶变换光谱仪，共计1305个NSR红外探测通道，覆盖长波（655~1095 cm⁻¹）、中波（1210~1750 cm⁻¹）与短波（2155~2550 cm⁻¹）三个光谱区域；ATMS仪器则为跨轨扫描仪，拥有22个光谱通道，波段范围覆盖23 GHz至183 GHz。

CLIMCAPS算法采用最优估计（Optimal Estimation）方法，并以先验初始猜测值作为流程启动依据。CLIMCAPS探测结果由一组表征完整大气状态的参数构成，包含从CrIMSS数据中提取的多类地球物理参数，具体包括地表温度与红外发射率、温度/水汽/臭氧的全大气廓线、红外有效云顶特征，以及一氧化碳、甲烷、二氧化碳、二氧化硫、一氧化二氮和硝酸等大气成分参数。

这款每日更新的1°纬度×1°经度的三级（level-3）产品，以质量控制（Quality Control，QC）值为0（最优）、1（合格）、2（弃用）的二级（level-2）反演产品为基础，该质控值针对每个变量单独设定，并通过特定质控流程进行处理。特定质控逻辑为保留从大气顶层向下直至质控判定仍合格的廓线层级，低于该层级的数据将被剔除。

警告：针对衍生产品"co_mmr_midtrop"（约500 hPa处的一氧化碳质量混合比与干空气的比值[kg/kg]）的用户。该变量存在显著偏差，源于转换误差：原计算中误用了二氧化碳（CO₂，摩尔质量48.01 g/mol）的摩尔质量，而非一氧化碳（CO，摩尔质量28.01 g/mol）。修正方式为将"co_mmr_midtrop"乘以28.01/48.01。或者，可通过二级文件中的反演柱密度值（"mol_lay/co_mol_lay"）从头推导质量混合比廓线。若有进一步疑问或问题，请联系探测器科学仪器处理团队（Sounder SIPS），邮箱：[e-mail]