Rapid ablation zone expansion amplifies north Greenland mass loss: modelled (RACMO2) and observed (MODIS) data sets

• Main Author: Noël, Brice P Y
• Format: Dataset
• Language: English
• Published: PANGAEA 2019
• Subjects: File format; File name; File size; Greenland; Greenland_Ice; RACMO; Uniform resource locator/link to file; Arctic; albedo; Ice Sheet; North Greenland
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.904428; https://doi.org/10.1594/PANGAEA.904428

Since the early 1990s, the Greenland ice sheet (GrIS) has been losing mass at an accelerating rate, primarily due to enhanced meltwater runoff following an atmospheric warming of ~1ºC. Here we show that a pronounced latitudinal contrast exists in the GrIS response to recent warming. The ablation area in north Greenland expanded by 46%, almost twice as much as in the south (+25%), significantly increasing the relative contribution of the north to total GrIS mass loss. This latitudinal contrast originates from a different response to the recent change in large-scale Arctic summertime atmospheric circulation, promoting southwesterly advection of warm air towards the GrIS. In the southwest, persistent high atmospheric pressure reduced cloudiness, increasing runoff through enhanced absorption of solar radiation; in contrast, increased early-summer cloudiness in north Greenland enhanced atmospheric warming through decreased longwave heat loss. This triggered a rapid snowline retreat, causing early bare ice exposure, amplifying northern runoff. The data set includes: 5.5 km data: annual mean summertime (June-July-August) shortwave down/upward radiation (swsd/swsu; W m-2), longwave down/upward radiation (lwsd/lwsu; W m-2), surface albedo (alb; unitless) and cloud content (qci; kg m-2) modelled by RACMO2.3p2 at 5.5 km spatial resolution for the period 1958-2017. 1 km data: annual cumulative meltwater runoff (kg m-2 or mm w.e.) modelled by RACMO2.3p2 at 5.5 km resolution and further statistically downscaled to 1 km for the period 1958-2017. Annual maximum bare ice extent (unitless) remotely sensed by MODIS at 1 km spatial resolution for the period 2000-2018. Mask file at 1 km resolution including longitude/latitude coordinates and outlines of the seven Greenland ice sheet sectors investigated in the study. Additional RACMO2.3p2 data, including daily downscaled surface mass balance (SMB) components at 1 km and modelled climate variables at 5.5 km resolution, are freely available from the authors upon request and without ...