MetOp-A/IASI Observed Continental Thermal IR Emissivity Variations

Satellite thermal infrared (IR) spectral emissivity data have been shown to be significant for atmospheric research and monitoring the Earth's environment. Long-term and large-scale observations that are needed for global monitoring and research can only be supplied by satellite-based remote sensing. Presented here is the global surface IR emissivity data retrieved from the last five and half years of Infrared Atmospheric Sounding Interferometer (IASI) measurements observed from the MetOp-A satellite. Monthly mean surface properties (i.e., skin temperature $T_{rm s}$ and spectral emissivity $varepsilon_{nu}$) with a spatial resolution of 0.5 $times$ 0.5-degrees latitude-longitude are produced to monitor seasonal and inter-annual variations. Continental IR spectral emissivity derived from satellite ultraspectral IR measurements reveals its variation depending on surface weather and climate conditions. Variation behaviors of continental IR spectral emissivity, associated with the seasonal change as well as weather and climate conditions are initially captured by IASI measurements and will be continuously monitored as provided by the satellite measurements. Surface $varepsilon_{nu}$ retrieved with IASI measurements can be used to assist in monitoring surface weather and surface climate change. Surface $varepsilon_{nu}$ together with $T_{rm s}$ from current and future operational weather satellites can be utilized as a means of long-term and large-scale monitoring of Earth's surface weather environment and associated changes.