The Madden-Julian Oscillation (MJO) impacts a wide range of weather and climate phenomena. Current global coupled ocean-atmospheric models (CGCMs) exhibit considerable shortcomings in representing and predicting the MJO, specifically its initiation, due to a lack of in situ observations. Here we show, for the first time, that the MJO propagation can be detected from the newly launched NASA Aquarius Salinity mission. The magnitude and extent of Sea Surface Salinity (SSS) variations during the MJO is established, providing a useful tool for data assimilation into models to correctly represent both oceanic and atmospheric processes during intraseasonal variations. Salinity observation allows for atmospheric conditions to be inferred from freshwater flux, on which surface salinity is highly dependent. Increased observations of global SSS from the Aquarius mission will be particularly valuable in remote regions of the tropics and will increase our dynamical understanding and advance prediction of the MJO through model improvement.
Composites of SSS anomalies during different stages of the MJO propagation. Composites are produced using the same event dates identified to create Figure 1. Statistically significant anomalies at the 90% level are indicated with solid contours. The box in a) represents the region where spatial averages are taken (5°S to 5°N, 87.5°E to 92.5°E).
Reference: Grunseich, G., B. Subrahmanyam, and Bin Wang (2013). Aquarius Salinity observations detect the Madden-Julian Oscillation, Geophysical Research Letters, 40, 1-6, doi: 10.1002/2013GL058173