GRACE

Retreating glacier south of Mt. Pendleton in Denali National Park, Alaska, with runoff from glacial melt seen in the foreground. Photo: Dennis G. Dye, U.S. Geological Survey. Public domain.

The Use of Gravimetry Satellites for Measuring Ice and Sea Level Change

Mark Altaweel

Satellites now allow researchers to make more accurate mass measurements to large areas covered by ice and understand the effects of snow and ice melt on sea level change.

Changes in Earth’s gravity field resulting from loss of ice from West Antarctica between November 2009 and June 2012 (mE = 10–12 s–2). A combination of data from ESA’s GOCE mission and NASA’s Grace satellites shows the ‘vertical gravity gradient change’.

Measuring Small Variations in the Earth’s Gravity

Caitlin Dempsey

The NASA–German Grace satellites were launched in May of 2002 in order to map variations in Earth's gravity field.

GRACE based shallow groundwater drought indicator map for July 7, 2014. Source: NASA.

Using Remote Sensing to Measure the Effect of Drought on Ground Water

Caitlin Dempsey

This map shows a comparison of modeled relative amount of water stored in underground aquifers in the continental United States for July 7, 2014 as compared to the average for comparable weeks for the sixty year average water storage.