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  • 1
    Publication Date: 2023-07-25
    Description: Long believed to be insignificant, melt activity on the Northeast Greenland Ice Stream (NEGIS) has increased in recent years. Summertime Arctic clouds have the potential to strongly affect surface melt processes by regulating the amount of radiation received at the surface. However, the cloud effect over Greenland is spatially and temporally variable and high‐resolution information on the northeast is absent. This study aims at exploring the potential of a high‐resolution configuration of the polar‐optimized Weather Research & Forecasting Model (PWRF) in simulating cloud properties in the area of the Nioghalvfjerdsfjorden Glacier (79 N Glacier). Subsequently, the model simulations are employed to investigate the impact of Arctic clouds on the surface energy budget and on surface melting during the extensive melt event at the end of July 2019. Compared to automatic weather station (AWS) measurements and remote‐sensing data (Sentinel‐2A and the Moderate Resolution Imaging Spectroradiometer, MODIS), PWRF simulates cloud properties with sufficient accuracy. It appears that peak melt was caused by an increase in solar radiation and sensible heat flux (SHF) in response to a blocking anticyclone and foehn winds in the absence of clouds. Cloud warming over high‐albedo surfaces helped to precondition the surface and prolonged the melting as the anticyclone abated. The results are sensitive to the surface albedo and suggest spatiotemporal differences in the cloud effect as snow and ice properties change over the course of the melting season. This demonstrates the importance of including high‐resolution information on clouds in analyses of ice sheet dynamics.
    Description: German Federal Ministry for Education and Research http://dx.doi.org/10.13039/501100002347
    Description: https://doi.org/10.5065/EM0T-1D34
    Description: https://cds.climate.copernicus.eu/cdsapp/#!/search?type=dataset
    Description: https://ladsweb.modaps.eosdis.nasa.gov/search/
    Keywords: ddc:551.5 ; cloud properties ; cloud radiative effect ; Northeast Greenland Ice Stream ; regional climate modeling ; surface energy balance ; surface melt ; surface energy balance ; surface melt
    Language: English
    Type: doc-type:article
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  • 2
    Publication Date: 2024-04-20
    Description: Tropical glaciers are helpful indicators of climatic changes in high-altitude environments. In East Africa, the glaciers in the three high-mountain regions Kilimanjaro, Mount Kenya and the Rwenzori Range have retreated substantially since the late 19th century. However, as there are no recent estimates for all regions, our study updates the time series of tropical glacier extent in East Africa. The methodological approach of the investigation is manual detection of ice body margins based on high-resolution satellite images of the PlanetScope program from 2021/2022. We performed three types of detection that included a minimum, a primary and a maximum extent, to indicate the range of the probable glacier area and account for individual allocation of pixels and influences of shaded or snow-covered areas.
    Keywords: Binary Object; Binary Object (Character Set); Binary Object (File Size); Binary Object (MD5 Hash); Binary Object (Media Type); East Africa; Kilimanjaro; Mount Kenya; Rwenzori; Satellite imagery; SATI; Tropical Climate; tropical glacier
    Type: Dataset
    Format: text/tab-separated-values, 54 data points
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  • 3
    Publication Date: 2024-04-20
    Description: Glaciers on Kilimanjaro are unique indicators for climatic changes in the tropical mid-troposphere of Africa. The history of severe glacier area loss raises concerns about an imminent future disappearance. Yet, the remaining ice volume is not well known. We reconstruct thickness maps for 2000 and 2011 for the Northern Icefield (NIF) and Kersten Glacier (KG) that are informed by ground-truth thickness measurements and multi-temporal satellite information. For 2011, we find mean thickness values of 26.6 and 9.3 m, respectively. The existing consensus estimate for global glacier ice thickness shows unrealistically thick values for KG in areas that are meanwhile ice-free. The ice thickness fields show the ice thickness in meters for the 2011 reconstruction (Experiment 3) outlined in the linked publication.
    Keywords: Binary Object; Event label; GPR; Ground-penetrating radar; ice thickness; Kersten_Glacier; KG; Kilimanjaro Northern Ice Field; KNIF; Mount Kilimanjaro, Tanzania
    Type: Dataset
    Format: text/tab-separated-values, 3 data points
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