Vertical resolution of oversampled limb-sounding measurements from satellites and aircraft

Measurements of trace gases by remote sensors which observe the atmospheric limb have a natural verticalresolution of 2–. With a typical field of view this becomes 3–. Oversampling, combined with acceptance of a degradation in random error, improves the verticalresolution. We investigate the improvement by means of Backus–Gilbert trade-off curves. Sacrificing a factor 10 in random error results in resolutions of for measurements of weak absorption or emission, and for strong pressure-broadened absorption. Weighting function calculations are technically more difficult for airborne than for satellitelimb-sounders; oversampled functions cause more technical difficulty.