To What Extent Aquarius Surface Salinity Measurements Can Detect Large-Scale, Low-Frequency Climate Signals?
[11-Nov-2014] Lee, T.
Presented at the 2014 Aquarius/SAC-D Science Team Meeting
Existing evaluations of the uncertainty of Aquarius sea surface salinity (SSS) measurements often include the errors both on small scales (e.g., at the Aquarius footprint) and short time scales (e.g., month-to-month time scales) as well as errors on the larger scales and longer time scales. The former errors often overwhelmed the latter ones, making it difficult to assess Aquarius' ability to detect large-scale signals associated with climate variability. The latter assessment is important to justify the continuation of Aquarius-like measurements to monitor decadal variability and climate change signals and to the planning of NASA's decadal survey missions. Historical in-situ salinity observations showed that the changes of SSS in the past few decades have typical scales on the order of 1000 km and with a typical magnitude of 0.2 psu over 50 years (e.g., Durack and Wijffels 2010). These changes imply an acceleration of the global water cycle, making fresh regions fresher and salty regions saltier. This presentation will present results of the analysis of uncertainty of Aquarius SSS data on scales of 1000 km with a focus on year-to-year changes currently resolved by Aquarius in order to shed light on the extent to which Aquarius can detect climate variability and change signals like these.