Dallas Masters's blog
NASA mission takes stock of Earth's melting land ice - In the first comprehensive satellite study of its kind, a University of Colorado at Boulder-led team used NASA data to calculate how much Earth's melting land ice is adding to global sea level rise. [NASA Climate News]
Our colleagues at JPL have also been interested in how the global mean sea level is affected by the ENSO (i.e., El Niño and La Niña). They find that GRACE measurements helped to identify the distribution of abnormally high rainfall over land resulting from the recent strong La Niña. This temporary transfer of large volumes of water from the oceans to the land surfaces also helps explain the large drop in global mean sea level. But they also expect the global mean sea level to begin climbing again.
An Update from NASA's Sea Level Sentinels:
Like mercury in a thermometer, ocean waters expand as they warm. This, along with melting glaciers and ice sheets in Greenland and Antarctica, drives sea levels higher over the long term. For the past 18 years, the U.S./French Jason-1, Jason-2 and Topex/Poseidon spacecraft have been monitoring the gradual rise of the world's ocean in response to global warming.
While the rise of the global ocean has been remarkably steady for most of this time, every once in a while, sea level rise hits a speed bump. This past year, it's been more like a pothole: between last summer and this one, global sea level actually fell by about a quarter of an inch, or half a centimeter.
So what's up with the down seas, and what does it mean? Climate scientist Josh Willis of NASA's Jet Propulsion Laboratory, Pasadena, Calif., says you can blame it on the cycle of El Niño and La Niña in the Pacific. [Read more...]
We recently updated the global mean sea level time series through Jason-2 cycle 102. In this release, we updated the sea state bias model (SSB) for TOPEX to the CLS Collinear v. 2009 model (Jason-1 and Jason-2 were already updated to this same model in 2011_rel1). Additionally, we replaced the classical inverted barometer correction with the improved AVISO Dynamic Atmopshere Correction (DAC) for all missions. Although the latest Jason-2 GMSL estimates are well below the trend line, the rate increased slightly from 3.1 to 3.2 mm/yr due to the improvements to the TOPEX SSB model and replacement of the classical IB correction with the improved DAC correction.
We also began comparing the GMSL time series to the Multivariate ENSO Index since previous studies have shown that GMSL and ENSO changes are correlated. From the quick comparison, changes in the MEI tend to lead changes in the GMSL. Therefore, as the recent strong La Niña wanes, we expect the recent drop in GMSL to reverse and begin increasing (following the MEI reversal). We will continue investigating this in more detail.