An Approach to the Detection of Long-Term Trends in Upper Stratospheric Ozone from Space

Abstract

A central problem in the detection of long-term trends in upper stratospheric ozone from orbiting remote sensors involves the separation of instrument drifts from true geophysical changes. Periodic flights of a Solar Backscatter Ultraviolet radiometer (SSBUV) on the Space Shuttle will allow the detection of drifts in optically identical sensors (SBUV/2) carried on operational satellites. A detailed simulation of the SSBUV and SBUV/2 datasets defines the accuracy that can be attained by the in-orbit calibration procedure. The repeatability of the SSBUV calibration from one flight to the next is the most critical variable in the analysis. A repeatability near ±1% is essential for detection and correction of drifts in the SBUV/2 radiance measurements. The simulations show that one can infer true geophysical trends in backscattered radiance to an accuracy of approximately ±1.0% per decade when SSBUV flies approximately once per year and provides a precise calibration correction to the SBUV/2 dataset over a full decade.