Observing System Studies for Climate

The existing meteorological observing system is not ideal for climate monitoring purposes. Efforts are currently under way to improve the upper-air system for in situ climate monitoring, which demand specific observing system requirements for climate.

We have recently completed an assessment of the effects of frequency and temporal consistency of radiosonde observations on our ability to measure changes in upper-air temperatures (Seidel and Free 2006). Our past work has also evaluated the effects of spatial sampling on trends in radiosonde data (Free and Seidel 2005).

These studies were used in recent workshops, sponsored by NOAA the international Global Climate Observing System program, with the goal of designing an improved radiosonde network. A GCOS report entitled "GCOS Reference Upper-Air Network (GRUAN): Justification, Requirements, Siting and Instrumentation Options" describes these international efforts.