NASA - National Aeronautics and Space Administration

We present, to the best of our knowledge, a new method to retrieve tropospheric ozone ͑O3͒ profiles from ground-based ultraviolet spectroscopic measurements. This method utilizes radiance spectra in the Huggins bands ͑i.e., 300–340 nm͒ measured at three off-axis angles (e.g., 45°, 75°, and 85°) normalized to direct-Sun irradiances or zenith-sky radiances with the total column O3 derived from direct-Sun or zenith-sky measurements as a constraint. The vertical resolution of the retrieved O3 values ranges from ϳ3 km near the surface to ϳ12 km at 20 km altitude. This method can be used to measure diurnal variation of tropospheric O3 profiles and is complementary to the Umkehr method that mainly measures ozone profiles in the stratosphere.