Microwave radiometer instability due to infrequent calibration
Kevin J. Coakley, Jolene D. Splett, Dave K. Walker, Mustafa Aksoy, Paul E. Racette
We directly quantify the effect of infrequent calibration on the stability of microwave radiometer temperature measurements (where a power measurement for the unknown source is acquired at a fixed time but calibration data are acquired at variable earlier times) with robust %(where outliers are down-weighted) and non-robust implementations of a new metric. We apply our metric to experimental data acquired from a NIST radiometer (NFRad) and experimental ground-based calibration data acquired from NASA's millimeter-wave imaging radiometer (MIR). Based on a stochastic model for NFRad, we determine the random uncertainty of an empirical model prediction of our stability metric by a Monte Carlo method. For comparison purposes, we also present a secondary metric that quantifies stability for the case where calibration data are acquired at a fixed time, but power measurements for the unknown source are acquired at variable later times.
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing