Temperature, H₂O, and O₃ profiles, as well as CO₂, N₂O, CH₄, chlorofluorocarbon-12 (CFC-12), and sea surface temperature (SST) scalar anomalies are computed using a clear subset of AIRS observations over ocean for the first 16 years of NASA's Earth-Observing Satellite (EOS) Aqua Atmospheric Infrared Sounder (AIRS) operation. The AIRS Level-1c radiances are averaged over 16 d and 40 equal-area zonal bins and then converted to brightness temperature anomalies. Geophysical anomalies are retrieved from the brightness temperature anomalies using a relatively standard optimal estimation approach. The CO₂, N₂O, CH₄, and CFC-12 anomalies are derived by applying a vertically uniform multiplicative shift to each gas in order to obtain an estimate for the gas mixing ratio. The minor-gas anomalies are compared to the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL) in situ values and used to estimate the radiometric stability of the AIRS radiances. Similarly, the retrieved SST anomalies are compared to the SST values used in the ERA-Interim reanalysis and to NOAA's Optimum Interpolation SST (OISST) product. These intercomparisons strongly suggest that many AIRS channels are stable to better than 0.02 to 0.03 K per decade, well below climate trend levels, indicating that the AIRS blackbody is not drifting. However, detailed examination of the anomaly retrieval residuals (observed – computed) shows various small unphysical shifts that correspond to AIRS hardware events (shutdowns, etc.). Some examples are given highlighting how the AIRS radiance stability could be improved, especially for channels sensitive to N₂O and CH₄. The AIRS shortwave channels exhibit larger drifts that make them unsuitable for climate trending, and they are avoided in this work. The AIRS Level 2 surface temperature retrievals only use shortwave channels. We summarize how these shortwave drifts impacts recently published comparisons of AIRS surface temperature trends to other surface climatologies.

中文翻译：

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利用微量气体和海面温度的辐射异常反演来建立AIRS气候水平的辐射稳定性

使用AIRS的清晰子集来计算温度，H ₂ O和O ₃剖面以及CO ₂，N ₂ O，CH ₄，氯氟烃12（CFC-12）和海面温度（SST）标量异常美国国家航空航天局（NASA）的地球观测卫星（EOS）水上大气红外测深仪（AIRS）运行的头16年中对海洋的观测。AIRS Level-1c辐射在16 d和40个等面积的纬向区域平均，然后转换为亮度温度异常。使用相对标准的最佳估计方法从亮度温度异常中检索地球物理异常。该CO₂， N ₂ O， CH ₄通过对每种气体应用垂直均一的乘法偏移来获得CFC-12异常，以获得气体混合比的估计值。将次要气体异常与美国国家海洋和大气管理局（NOAA）地球系统研究实验室（ESRL）的原位值进行比较，并用于估算AIRS辐射的辐射稳定性。同样，将检索到的SST异常与ERA-Interim重新分析中使用的SST值以及NOAA的最佳插值SST（OISST）产品进行比较。这些相互比较强烈表明，许多AIRS通道稳定到每十年0.02至0.03 K以上，远低于气候趋势水平，表明AIRS黑体没有漂移。然而，对异常取回残差的详细检查（观察到的-计算得出的）显示出各种与AIRS硬件事件（关机等）相对应的微小的非物理位移。给出了一些示例，重点说明如何改善AIRS辐射稳定性，尤其是对于对N ₂ O和CH ₄。AIRS短波通道表现出较大的漂移，使其不适合气候趋势，因此在这项工作中避免使用。AIRS 2级表面温度检索仅使用短波通道。我们总结了这些短波漂移如何影响AIRS表面温度趋势与其他表面气候的最新发表的比较。