A5035781872- Cryospheric studies and observations
- Climate change and permafrost
- Climate variability and models
- Geology and Paleoclimatology Research
- Arctic and Antarctic ice dynamics
- Landslides and related hazards
- Winter Sports Injuries and Performance
- Atmospheric and Environmental Gas Dynamics
- Meteorological Phenomena and Simulations
- Methane Hydrates and Related Phenomena
- Oceanographic and Atmospheric Processes
- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Hydrology and Watershed Management Studies
- Peatlands and Wetlands Ecology
- Polar Research and Ecology
- Geological Studies and Exploration
- Hydrocarbon exploration and reservoir analysis
- Isotope Analysis in Ecology
- Geophysics and Gravity Measurements
- Atmospheric aerosols and clouds
- demographic modeling and climate adaptation
- Icing and De-icing Technologies
- Indigenous Studies and Ecology
- Geological and Geophysical Studies
Aarhus University
2020-2025
Danish Meteorological Institute
2012-2021
University of Copenhagen
2004-2020
University of Bonn
2020
Abstract. Observations and models agree that the Greenland Ice Sheet (GrIS) surface mass balance (SMB) has decreased since end of 1990s due to an increase in meltwater runoff this trend will accelerate future. However, large uncertainties remain, partly different approaches for modelling GrIS SMB, which have weigh physical complexity or low computing time, spatial temporal resolutions, forcing fields, ice sheet topographies extents, collectively make inter-comparison difficult. Our SMB model...
To improve Greenland Ice Sheet surface mass balance (SMB) simulation, the subsurface scheme of HIRHAM5 regional climate model was extended to include snow densification, varying hydraulic conductivity, irreducible water saturation and other effects on liquid percolation retention. Sensitivity experiments investigate additions impact different parameterization choices are presented. Compared with 68 accumulation area ice cores, simulated mean annual net bias is -5% (correlation coefficient...
Abstract. Ice losses from the Greenland and Antarctic ice sheets have accelerated since 1990s, accounting for a significant increase in global mean sea level. Here, we present new 29-year record of sheet mass balance 1992 to 2020 Sheet Mass Balance Inter-comparison Exercise (IMBIE). We compare combine 50 independent estimates derived satellite observations temporal changes flow, volume, Earth's gravity field. Between 2020, contributed 21.0±1.9 mm level, with rate loss rising 105 Gt yr−1...
Abstract A vertically nonuniform warming of the troposphere yields a lapse rate feedback by altering infrared irradiance to space relative that uniform tropospheric warming. The is negative at low latitudes, as result moist convective processes, and positive high due stable stratification conditions effectively trap near surface. It shown this pattern leads polar amplification temperature response induced radiative forcing. results are obtained suppressing in Community Climate System Model,...
Abstract Surface ablation of the Greenland ice sheet is amplified by surface darkening caused light‐absorbing impurities such as mineral dust, black carbon, and pigmented microbial cells. We present first quantitative assessment contribution to darkening, based on field measurements reflectance concentrations impurities, including algae, during 2014 melt season in southwestern part sheet. The impact algae bare study area was greater than that nonalgal yielded a net albedo reduction 0.038 ±...
Significance Meltwater runoff is an important hydrological process operating on the Greenland ice sheet surface that rarely studied directly. By combining satellite and drone remote sensing with continuous field measurements of discharge in a large supraglacial river, we obtained 72 h observations suitable for comparison climate model predictions. The quantify how large, fluvial catchment attenuates magnitude timing delivered to its terminal moulin hence bed. data are used calibrate...
Abstract Freshwater runoff to fjords with marine-terminating glaciers along the Greenland Ice Sheet margin has an impact on fjord circulation and potentially ice sheet mass balance through increasing heat transport glacier front. Here, authors use high-resolution (5.5 km) HIRHAM5 regional climate model, allowing high detail in topography surface types, estimate freshwater input Godthåbsfjord southwest Greenland. Model output is compared hydrometeorological observations and, while simulated...
Abstract During two exceptionally large July 2012 multiday Greenland ice sheet melt episodes, nonradiative energy fluxes (sensible, latent, rain, and subsurface collectively) dominated the ablation area surface budget of southern western sheet. On average contributed up to 76% daily at nine automatic weather station sites in Greenland. Comprising 6% period, these powerful episodes resulted 12–15% south west annual totals. Analysis high resolution (~5 km) HIRHAM5 regional climate model output...
Abstract. Perennial snow, or firn, covers 80 % of the Greenland ice sheet and has capacity to retain surface meltwater, influencing mass balance contribution sea-level rise. Multilayer firn models are traditionally used simulate processes estimate meltwater retention. We present, intercompare evaluate outputs from nine at four sites that represent sheet's dry percolation, slab aquifer areas. The forced by energy fluxes derived automatic weather stations compared density, temperature...
Abstract. The mass of the Greenland ice sheet is declining as gain from snow accumulation exceeded by loss surface meltwater runoff, marine-terminating glacier calving and submarine melting, basal melting. Here we use input–output (IO) method to estimate change 1840 through next week. Surface balance (SMB) gains losses come a semi-empirical SMB model 1985 three regional climate models (RCMs; HIRHAM/HARMONIE, Modèle Atmosphérique Régional – MAR, RACMO Regional Atmospheric Climate MOdel) 1986...
ABSTRACT This article assesses the performance of surface mass balance (SMB) and temperature products from seven climate models (ERA5, MERRA2, HIRHAM5_ERA‐Interim, HIRHAM5_ERA5, MARv3.11, RACMO2.3p1 RACMO2.3p2) to be used as inputs firn densification (FDMs), crucial for whole Antarctic estimation. The evaluation compiles utilises a new dataset combining existing observations with 184 stake SMB measurements in Vostok region two radar transects Blåskimen Island Nivlisen Ice Shelf,...
Understanding the reasons for which current climate models fail to reproduce low equator‐to‐pole temperature gradient of past warm periods is among major challenges in science. We focus here on role atmospheric poleward heat transport. use an aquaplanet general circulation model (GCM) construct a regime diagram this quantity as function surface and its meridional gradient, encompassing range experienced by Earth over Cenozoic. find that transport increases with much range, but saturates...
Abstract Reduction of the Arctic sea ice cover can affect atmospheric circulation and thus impact climate beyond Arctic. The response may, however, vary with geographical location loss. sensitivity to loss is studied using a general model in configuration that allows combination prescribed an active mixed layer ocean. This hybrid setup makes it possible simulate isolated provides more complete compared experiments fixed surface temperatures. Three investigated scenarios different regions all...
ABSTRACT Understanding the drivers of recent change at Greenlandic tidewater glaciers is great importance if we are to predict how these will respond climatic warming. A poorly constrained component glacier processes near-terminus subglacial hydrology. Here present a novel method for constraining hydrology with application marine-terminating Kangiata Nunata Sermia in South-west Greenland. By simulating proglacial plume dynamics using buoyant theory and general circulation model, assess...
Abstract. The Greenland Ice Sheet (GrIS) mass loss has been accelerating at a rate of about 20 ± 10 Gt/yr2 since the end 1990's, with around 60 % this directly attributed to enhanced surface meltwater runoff. However, in climate and glaciology communities, different approaches exist on how model balance (SMB) components using: (1) complex physically-based models which are computationally expensive; (2) intermediate complexity energy models; (3) simple fast positive degree day base their...
Abstract. Antarctic surface mass balance (SMB) is largely determined by precipitation over the continent and subject to regional climate variability related Southern Annular Mode (SAM) other climatic drivers at large scale. Locally however, firn snowpack processes are important in determining SMB total of Antarctica global sea level. Here, we examine factors that influence attempt reconcile outcome with estimates for from GRACE satellites. This done having model HIRHAM5 forcing two versions...