Blar i forfatter "Graversen, Rune Grand"

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    • Change in Climate Sensitivity and Its Dependence on the Lapse-Rate Feedback in 4 x CO2 Climate Model Experiments 

      Eiselt, Kai-Uwe; Graversen, Rune Grand (Journal article; Tidsskriftartikkel, 2022-04-19)
      Robust estimates of climate sensitivity are important for decision-making on mitigation of climate change. However, climate sensitivity and its governing processes are still subject to large uncertainty. Recently it has been established that climate sensitivity changes over time in numerical climate model experiments with abrupt quadrupling of the CO<sub>2</sub> concentration. Here we conduct an ...

    • Comparing wavelet and Fourier perspectives on the decomposition of meridional energy transport into synoptic and planetary components 

      Heiskanen, Tuomas Ilkka Henrikki; Graversen, Rune Grand; Rydsaa, Johanne Hope; Isachsen, Pål Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-04)
      The Arctic region shows some of the world's most significant signs of climate change; for instance, a negative trend in summer sea‐ice cover of around 15% per decade and Arctic amplified surface‐air warming that is three times the global average. The atmospheric energy transport plays an important role in the Arctic climate. Recently a Fourier‐based method for studying the atmospheric energy transport ...

    • The impact of atmospheric Rossby waves and cyclones on the Arctic sea ice variability 

      Hofsteenge, Marte G.; Graversen, Rune Grand; Rydsaa, Johanne Hope; Rey, Zoé (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-17)
      The Arctic sea-ice extent has strongly declined over recent decades. A large inter-annual variability is superimposed on this negative trend. Previous studies have emphasised a significant warming effect associated with latent energy transport into the Arctic region, in particular due to an enhanced greenhouse effect associated with the convergence of the humidity transport over the Arctic. The ...

    • A nested high-resolution unstructured grid 3-D ocean-sea ice-ice shelf setup for numerical investigations of the Petermann ice shelf and fjord 

      Prakash, Abhay; Zhou, Qin; Hattermann, Tore; Bao, Weiyang; Graversen, Rune Grand; Kirchner, Nina (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-18)
      Three-dimensional numerical simulation of circulation in fjords hosting marine-terminating ice shelves is challenging because of the complexity of processes involved in such environments. This often requires a comprehensive model setup. The following elements are needed: bathymetry (usually unknown beneath the glacier tongue), ice shelf draft (impacting water column thickness), oceanographic state ...

    • On the Control of Northern Hemispheric Feedbacks by AMOC: Evidence from CMIP and Slab Ocean Modeling 

      Eiselt, Kai-Uwe; Graversen, Rune Grand (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-06)
      The climate sensitivity of Earth and the radiative climate feedback both change over time as a result of a so-called “pattern effect,” i.e., changing patterns of surface warming. This is suggested by numerical climate model experiments. The Atlantic meridional overturning circulation (AMOC) influences surface warming patterns as it redistributes energy latitudinally. Thus, this ocean circulation may ...

    • Springtime nitrogen oxides and tropospheric ozone in Svalbard: results from the measurement station network 

      Dekhtyareva, Alena; Hermanson, Mark H.; NIkulina, Anna; Hermansen, Ove; Svendby, Tove Marit; Holmén, Kim; Graversen, Rune Grand (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-09)
      Svalbard is a remote and scarcely populated Arctic archipelago and is considered to be mostly influenced by long-range-transported air pollution. However, there are also local emission sources such as coal and diesel power plants, snowmobiles and ships, but their influence on the background concentrations of trace gases has not been thoroughly assessed. This study is based on data of tropospheric ...

    • Validation of a SAR-only wind-vector retrieval against shipborne in situ wind observations in the European Arctic 

      Tollinger, Mathias; Graversen, Rune Grand (Journal article; Tidsskriftartikkel, 2024-01-05)
      Space-borne synthetic aperture radar (SAR) observations provide broad coverage of high-resolution snapshots of the sea surface conditions in polar regions. However, their potential has not yet been fully harnessed for meteorological applications. For instance, standard methods for SAR wind-vector retrieval rely on wind direction inputs from numerical weather prediction models, which hampers the ...