| The relationship between differences in microwave humidity sounder(MHS)measured brightness temperatures(O)and model-simulated brightness temperatures(B;O-B),and cloud ice water path(IWP)as well as the influence of the cloud liquid water path(LWP)on the relationship is examined.Seven years(2011–2017)of NOAA-18 MHS-derived O and IWP/LWP data generated by the NOAA Comprehensive Large Array-data Stewardship System(CLASS)Microwave Surface and Precipitation Products System are used.The Community Radiative Transfer Model version 2.2.4 is used to simulate B using European Center for Medium-Range Weather Forecasts reanalysis data as background fields.Scan-angle deviations of the MHS window channel O-B biases range from-1.7 K to 1.0 K.The relationships between channels 2,4,and 5 O-B biases and scan angle are symmetrical about the nadir.The latitudedependent deviations of MHS window channel O-B biases are positive and range from 0–7 K.For MHS non-window channels,the O-B latitudinal deviations are larger when the detection height is higher.No systematic warm or cold deviations are found in the global spatial distribution of O-B over oceans after removing O-B scan-angle and latitudinal deviations,i.e.,O-B-μ(α)-μ(φ)where μ(α)and μ(φ)represents scan-angle and latitudinal deviations of the O-B biases,respectively.The O-B-μ(α)-μ(φ)of five different MHS channels decrease differently with respect to the increase in IWP.This decrease is stronger when LWP values are higher. |
