Climate Signal Detection Times and Constraints on Climate Benchmark Accuracy Requirements

Leroy, S. S., J. G. Anderson, and G. Ohring (2008), Climate signal detection times and constraints on climate benchmark accuracy requirements,J. Clim., 21, 841 – 846, doi:10.1175/2007JCLI1946.1.

Long term trends in the climate system are always partly obscured by naturally occurring interannual variability.All else being equal, the larger the natural variability is, the less precisely one can estimate a trend in a timeseriesof data. Measurement uncertainty, though, also obscures long term trends. We derive how measurement uncertaintyand natural interannual variability interact in inhibiting the detection of climate trends using simple linear regressionand show how the interaction between the two can be used to formulate accuracy requirements for satellite climatebenchmark missions. We find that measurement uncertainty increases detection times but only when considered indirect proportion to natural variability. We also find that detection times depend critically on the correlation time ofnatural variability and satellite lifetime. As a consequence, requirements on satellite climate benchmark accuracyand mission lifetime must be directly related to natural variability of the climate system and its associated correlationtimes.