Prof. Jianli Chen Published a Breakthrough Study in Nature
Prof. Jianli Chen, a professor in the Department of Land Surveying and Geo-Informatics, has co-authored a new study published in Nature, unveiling a surprising discovery: a substantial amount of meltwater is temporarily stored within the Greenland Ice Sheet during summer months. For the first time, an international group of researchers was able to quantify meltwater with positioning data. The finding challenges current models of how ice sheets contribute to global sea level rise.
The Greenland Ice Sheet is currently the largest single contributor to global sea level rise, with the potential to raise the mean sea level by up to seven meters if completely melted. While scientists have long studied the melt processes of the ice sheet, one crucial question has remained unanswered: how does meltwater storage evolve within the ice sheet throughout the summer melt season? A new approach provides an unprecedented view into the movement and storage of meltwater.
The team has utilized data from the Greenland GPS Network (GNET). The network consists of several tens of stations around Greenland that continuously provide positioning data. The team developed an innovative method that interprets the detected vertical displacements of the bedrock. These displacements are caused by, among others, the mass of melting water, pushing the bedrock down.
"During. the melt season, we found that a significant fraction of meltwater mass is stored temporarily within the ice sheet," says Jiangjun Ran, the lead author and associate professor at the Southern University of Science and Technology, "This water buffering effect peaks in July and slowly recedes in the following weeks."
“GRACE satellite gravity measurements provide independent validation of the significant finding from GNET surface deformation observations,” adds Prof. Chen, a world leading expert in satellite gravimetry, “Integrating different modern space geodetic techniques plays an important role in tackling the challenges of climate change.”
This discovery will help improve climate models, which often underestimate the complexity of water storage within ice sheets. Especially during warmer years, models that predict water runoff towards the ocean may easily underestimate that process. The study finds that these models could require scaling adjustments of up to 20% for the warmest years.
The study has taken years of preparation and required difficult expeditions to some of the most remote areas of the planet. This large joint effort highlights the importance of international collaboration in addressing one of the planet's most pressing environmental challenges.
The study was published on Oct. 30, 2024 in Nature: Vertical bedrocks shifts reveal summer water storage in Greenland ice sheet.
The Greenland Ice Sheet is currently the largest single contributor to global sea level rise, with the potential to raise the mean sea level by up to seven meters if completely melted. While scientists have long studied the melt processes of the ice sheet, one crucial question has remained unanswered: how does meltwater storage evolve within the ice sheet throughout the summer melt season? A new approach provides an unprecedented view into the movement and storage of meltwater.
The team has utilized data from the Greenland GPS Network (GNET). The network consists of several tens of stations around Greenland that continuously provide positioning data. The team developed an innovative method that interprets the detected vertical displacements of the bedrock. These displacements are caused by, among others, the mass of melting water, pushing the bedrock down.
"During. the melt season, we found that a significant fraction of meltwater mass is stored temporarily within the ice sheet," says Jiangjun Ran, the lead author and associate professor at the Southern University of Science and Technology, "This water buffering effect peaks in July and slowly recedes in the following weeks."
“GRACE satellite gravity measurements provide independent validation of the significant finding from GNET surface deformation observations,” adds Prof. Chen, a world leading expert in satellite gravimetry, “Integrating different modern space geodetic techniques plays an important role in tackling the challenges of climate change.”
This discovery will help improve climate models, which often underestimate the complexity of water storage within ice sheets. Especially during warmer years, models that predict water runoff towards the ocean may easily underestimate that process. The study finds that these models could require scaling adjustments of up to 20% for the warmest years.
The study has taken years of preparation and required difficult expeditions to some of the most remote areas of the planet. This large joint effort highlights the importance of international collaboration in addressing one of the planet's most pressing environmental challenges.
The study was published on Oct. 30, 2024 in Nature: Vertical bedrocks shifts reveal summer water storage in Greenland ice sheet.
