Last year, for the first time in recorded history, it rained on the top of the Greenland ice sheet.
Sitting atop 10,000 feet of ice with summertime temperatures that average about nine degrees Fahrenheit, the region has only had about 50 melt events with temperatures above freezing in the past 10,000 years, according to scientists who have studied ice cores there.
But with more than a half dozen melt events in the past decade and last summer’s highly anomalous rain storm, it’s clear that Greenland is changing.
A new $3.5 million National Science Foundation grant will allow researchers to study the snow and atmospheric conditions in Greenland during an era of climatic transition with the aim of providing better forecasts of the continent’s contribution to future sea level rise.
“The mass loss of Greenland is accelerating, and it’s all indicative of the fact that it is in a significant climate transition right now,” said Von P. Walden, professor in the Department of Civil and Environmental Engineering, who is leading the project. “We have a good overall idea of what’s going to happen as this region warms, but we want to provide the best forecast we can. To do that we need to understand these processes better.”
Scientists have long predicted that climate change would happen faster in the Arctic than at mid-latitudes. Greenland has been losing ice from its vast ice sheet at an accelerated rate in recent decades and has been shown to be a significant contributor to sea level rise, a worrying trend for millions of people around the world who live along coastlines.
Researchers have primarily used satellites to make measurements of how much ice Greenland is losing through melting as well as through ice “calving” or the breaking of large pieces of ice at the edge of the ice sheet. Harsh conditions and the continent’s remote location make direct measurements on the surface challenging. Measurements in the past have used instrumentation that use low power and mostly provide minimal weather information.
“There are experiments you can conduct on the ground that will be superior to anything you can do from a satellite,” Walden said. “Detailed measurements from a given location are very important for comparing to satellites, validating them, and maybe even more importantly, understanding the physical processes and coupling between the atmosphere, surface, and subsurface.”
Walden will lead a team including researchers from the University of Colorado, University of Wisconsin, Madison, Dartmouth College, Boise State University, and University of Leeds in England, to build and test an autonomous instrument platform. The instruments will make sophisticated measurements of precipitation, cloud properties, atmospheric and weather conditions, and ice and snow structure below the surface. The study area will be in southwest Greenland, a region that is melting at the highest rate on the continent. The platform will be situated in the percolation zone, an area of the ice sheet in which snow melts, percolates into the snow, and re-freezes, creating layers of ice in the snowpack.
The researchers aim to collect data through the harsh weather conditions in Greenland –in snow, freezing rain, or blinding blizzards. The platform will be deployed from May to August, powered primarily by solar and wind power to maintain state-of-the-art instrumentation.
“How much it’s raining versus snowing is pretty unknown and what the cloud and atmospheric properties are like during those different precipitation regimes — that’s a big thing that we’re adding to our measurements,” said Walden. “We’re trying to document what’s happening in the percolation zone now because we think it’s going to be quite different in 10, 20, or 30 years.”
