By Kelly

When we speak of GRACE here at OnCirculation we are usually referring to the Gravity Recovery and Climate Experiment rather than of courteous goodwill, or a former princess of Monaco with exceptional eyebrows. Our GRACE has made it back into the weekly journals, this time in Geophysical Research Letters with Phillips et al. reporting on the influence of the ENSO cycle on terrestrial water storage, using monthly estimate acquired from the GRACE project.

For those who need a quick recap, at RSES we have become quite familiar with GRACE and its application to estimating sea-level rise through the excellent work of Paul Tregoning; most recently at the Sea Level Forum held at the Australian National University this June. GRACE’s mission is to measure Earth’s gravity field to inform our understanding of Earth’s natural systems. It is able to do this by measuring the difference in speed and distance between two identical spacecraft travelling in the same orbit. This is an astonishing achievement when you consider that the system is sensitive enough to detect changes as little as 10 micrometres, between two craft that are ~220km apart, ~500 km from the Earth’s surface. But I digress, back to the article…

The authors analyzed data collected between 2003-2010, and were able to demonstrate a significant relationships between the ENSO index (from the National Oceanic and Atmospheric Administration) and water storage for the Amazon Basin and Borneo in Southeast Asia. More generally tropical regions were negatively correlated while arid regions positively correlated. The information gleaned from the project has shown to accurately reflect all known global teleconnection patterns, including the polar regions of the Antarctic, Alaska, and Greenland, but that these anomalies in water storage may lag in time.

The movement and melting of the Greenland ice sheet has received a lot of attention both in the public and scientific arenas of late (see here, here and here), with much commentary on the cause of the melting, i.e can we unequivocally attribute the potential loss of the ice sheet, and accompanying sea-level rise to human activity. The GRACE project is significantly improving many techniques used by Earth scientists to understand the processes that influence our climate.  This recent study suggests that there may be even more to consider if we are to understand the forcing mechanisms behind this melting phenomena in Greenland, and that is that some of the recent loss to Greenland’s mass could be related to the ENSO cycle.

You will need to be a member to download the full article from the AGU site, or you can see the abstract here.