New & Noteworthy Items

Dr. Rennermalm's research team in the news

2018 12 13 01.19.31 pm

Åsa Rennermalm's research group has been in the news recently! and The New York Times both wrote articles about a research project her team was participating in on Greenland ice sheet melt.

These write-ups drew from a paper her group published in Proceedings of the National Academies of Science, titled "Direct measurements of meltwater runoff on the Greenland ice sheet surface." Read the full article here.

Her research students were also featured on the Rutgers Today website. Take a look at it here: Sasha , Rohi, and Asa

The paper abstract follows: Meltwater runoff from the Greenland ice sheet surface influences surface mass balance (SMB), ice dynamics, and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river discharge measurements and simultaneous high-resolution satellite/drone remote sensing of upstream fluvial catchment area. A first 72-h trial for a 63.1-km2 moulin-terminating internally drained catchment (IDC) on Greenland’s midelevation (1,207–1,381 m above sea level) ablation zone is compared with melt and runoff simulations from HIRHAM5, MAR3.6, RACMO2.3, MERRA-2, and SEB climate/SMB models. Current models cannot reproduce peak discharges or timing of runoff entering moulins but are im- proved using synthetic unit hydrograph (SUH) theory. Retroactive SUH applications to two older field studies reproduce their findings, signifying that remotely sensed IDC area, shape, and supraglacial river length are useful for predicting delays in peak runoff delivery to moulins. Applying SUH to HIRHAM5, MAR3.6, and RACMO2.3 gridded melt products for 799 surrounding IDCs suggests their terminal moulins receive lower peak discharges, less diurnal vari- ability, and asynchronous runoff timing relative to climate/SMB model output alone. Conversely, large IDCs produce high moulin discharges, even at high elevations where melt rates are low. During this particular field experiment, models overestimated runoff by+21 to +58%, linked to overestimated surface ablation and possible meltwater retention in bare, porous, low-density ice. Direct mea- surements of ice surface runoff will improve climate/SMB models, and incorporating remotely sensed IDCs will aid coupling of SMB with ice dynamics and subglacial systems.