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The role of cloud-radiative effects and diabatic processes for the dynamics of the North Atlantic Oscillation on synoptic time-scales

Papavasileiou, Georgios

Abstract (englisch):

Clouds shape weather and climate by regulating the latent and radiative heating in the atmosphere.
Recent work demonstrated the importance of cloud-radiative effects (CRE) for the mean
circulation of the extratropical atmosphere and its response to global warming. In contrast,
little research has been done regarding the impact of CRE on internal variability. During the northern
hemisphere winter the dominant mode of atmospheric variability over the North Atlantic and the
surrounding continental areas of North America and Europe is the North Atlantic Oscillation (NAO).
Here, we study how clouds and the NAO couple on synoptic time-scales during northern hemisphere
winter via CRE within the atmosphere (ACRE) in observations and model simulations.

A regression analysis based on 5-day-mean data from CloudSat/CALIPSO reveals a robust
dipole of cloud-incidence anomalies during a positive NAO, with increased high-level clouds
along the storm track (near 45°N) and the subpolar Atlantic, and decreased high-level clouds
poleward and equatorward of it. Opposite changes occur for low-level cloud incidence. Satellite
retrievals from CloudSat/CALIPSO, CERES and GERB as well as ERA-Interim short-term
... mehr

Volltext §
DOI: 10.5445/IR/1000123919
Veröffentlicht am 23.09.2020
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung – Forschungsbereich Troposphäre (IMK-TRO)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Hochschulschrift
Publikationsdatum 23.09.2020
Sprache Englisch
Identifikator KITopen-ID: 1000123919
HGF-Programm 12.01.02 (POF III, LK 01) Proc.res.f.multisc.predictab.of weather
Verlag Karlsruher Institut für Technologie (KIT)
Umfang 113 S.
Art der Arbeit Dissertation
Fakultät Fakultät für Physik (PHYSIK)
Institut Institut für Meteorologie und Klimaforschung – Forschungsbereich Troposphäre (IMK-TRO)
Prüfungsdatum 24.07.2020
Schlagwörter atmospheric cloud-radiative effects (ACRE), clouds, radiation, cloud–circulation coupling, diabatic processes, latent heating, North Atlantic Oscillation (NAO), ICON, surface pressure tendency equation (PTE), diabatic heating, numerical modeling, CloudSat/CALIPSO, CERES, GERB, ERA5, ERA-Interim
Referent/Betreuer Knippertz, P.
KIT – Die Forschungsuniversität in der Helmholtz-Gemeinschaft
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