Knowledge of both the horizontal and vertical distributions of atmospheric water vapour is pivotal to understand the Earth’s radiative balance. The Atmospheric Infrared Sounder (AIRS) provides an opportunity to monitor both precipitable water vapour (PWV) measurements and water vapour mixing ratio (MR) profiles. In this study, we incorporate a differential linear adjust model (DLAM) by using the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Reanalysis (ERA-Interim) to adjust the AIRS water vapour retrievals. The performance of the differential linear adjustment model (DLAM) is assessed by comparing AIRS water vapour retrievals with spatio-temporally synchronized radiosonde (RS) observations. Taking RS data as the reference, RMS of the DLAM-adjusted PWV is reduced by about 16%, and that of water vapour MR is decreased by 17% to 8% from 1000 to 500 hPa. We also find that the DLAM appears to be affected by the generally larger uncertainties of the a priori water vapour MR at upper tropospheric levels, and the DLAM-derived water vapour MR improvement is generally greater from 1000 to 850 hPa than 700 to 500 hPa. Moreover, the potential reason for the effectiveness of the DLAM on AIRS water vapour retrievals adjustment may be the deviation of the differential water vapour information derived by the differential process is significantly reduced in the incorporated model.

了解大气水蒸气的水平和垂直分布对于了解地球的辐射平衡至关重要。大气红外测深仪（AIRS）提供了监视可沉淀水蒸气（PWV）测量和水蒸气混合比（MR）曲线的机会。在这项研究中，我们通过使用欧洲中距离天气预报中心（ECMWF）临时再分析（ERA-Interim）来调整AIRS水汽取回量，并引入了差分线性调整模型（DLAM）。通过比较AIRS水汽反演与时空同步探空仪（RS）观测值，评估了差分线性调整模型（DLAM）的性能。以RS数据为参考，DLAM调整后的PWV的RMS降低了约16％，从1000 hPa到500 hPa，水蒸气MR降低了17％到8％。我们还发现，DLAM似乎受到对流层较高水平的先验水蒸气MR总体上较大不确定性的影响，而DLAM派生的水蒸气MR改进从1000至850 hPa大于700至500 hPa。此外，DLAM对AIRS水汽取回量调整的有效性的潜在原因可能是在合并的模型中显着减少了由差分过程得出的差分水汽信息的偏差。并且DLAM衍生的水蒸气MR的改善从1000至850 hPa大于700至500 hPa。此外，DLAM对AIRS水汽取回量调整的有效性的潜在原因可能是在合并的模型中显着减少了由差分过程得出的差分水汽信息的偏差。并且DLAM衍生的水蒸气MR的改善从1000至850 hPa大于700至500 hPa。此外，DLAM对AIRS水汽取回量调整的有效性的潜在原因可能是在合并的模型中显着减少了由差分过程得出的差分水汽信息的偏差。