TY - JOUR A1 - Buehler, Stefan A. A1 - Prange, Marc A1 - Mrziglod, John A1 - John, Viju O. A1 - Burgdorf, Martin A1 - Lemke, Oliver T1 - Opportunistic Constant Target Matching—A New Method for Satellite Intercalibration Y1 - 2020 VL - 7 IS - 5 JF - Earth and Space Science DO - 10.1029/2019EA000856 DO - 10.23689/fidgeo-4700 N2 - Opportunistic constant target matching is a new method for satellite intercalibration. It solves a long-standing issue with the traditional simultaneous nadir overpass (SNO) method, namely, that it typically provides only data points with cold brightness temperatures for humidity sounding instruments on sun-synchronous satellites. In the new method, a geostationary infrared sensor (SEVIRI) is used to select constant target matches for two different microwave sensors (MHS on NOAA 18 and Metop A). We discuss the main assumptions and limitations of the method and explore its statistical properties with a simple Monte Carlo simulation. The method was tested in a simple case study with real observations for this combination of satellites for MHS Channel 3 at 183 ± 1 GHz, the upper tropospheric humidity channel. For the studied 3-month test period, real observations are found to behave consistently with the simulations, increasing our confidence that the method can be a valuable tool for intercalibration efforts. For the selected case study, the new method confirms that the bias between NOAA 18 and Metop A MHS Channel 3 is very small, with absolute value below 0.05 K. UR - http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/9046 ER -