The Spatial Heterodyne Observations of Water (SHOW) Instrument for High Resolution Profiling in the Upper Troposphere and Lower Stratosphere

The Spatial Heterodyne Observations of Water (SHOW) instrument is a prototype Canadian satellite instrument specifically designed to make high spatial resolution measurements of water vapor in the upper troposphere and lower stratosphere through vertical imaging of the limb scattered sunlight in a near infrared vibrational absorption band. The spatial heterodyne approach provides sufficient spectral resolution and signal-to-noise performance such that when combined with a multiple scattering forward model and a non-linear inversion, the SHOW measurements can be used to tomographically reconstruct the two dimensional water vapour distribution, i.e. in altitude along the satellite track. Here we present the motivation for the measurement, the instrument concept, prototype specifications and results from simulated measurements and retrievals.