Call number:
AWI A6-21-94541
Description / Table of Contents:
Stratospheric variability is one of the main potential sources for sub-seasonal to seasonal predictability in mid-latitudes in winter. Stratospheric pathways play an important role for long-range teleconnections between tropical phenomena, such as the quasi-biennial oscillation (QBO) and El Niño-Southern Oscillation (ENSO), and the mid-latitudes on the one hand, and linkages between Arctic climate change and the mid-latitudes on the other hand. In order to move forward in the field of extratropical seasonal predictions, it is essential that an atmospheric model is able to realistically simulate the stratospheric circulation and variability. The numerical weather prediction (NWP) configuration of the ICOsahedral Non-hydrostatic atmosphere model ICON is currently being used by the German Meteorological Service for the regular weather forecast, and is intended to produce seasonal predictions in future. This thesis represents the first extensive evaluation of Northern Hemisphere stratospheric winter circulation in ICON-NWP by analysing a ...
Type of Medium:
Dissertations
Pages:
viii, 119 Seiten
,
Illustrationen, Diagramme, Karten
URL:
https://nbn-resolving.org/urn:nbn:de:kobv:517-opus4-487231
URL:
https://doi.org/10.25932/publishup-48723
URN:
urn:nbn:de:kobv:517-opus4-487231
DOI:
10.25932/publishup-48723
Language:
English
Note:
Dissertation, Universität Potsdam, 2020
,
Contents1
Introduction
1.1 Motivation: Seasonal prediction
1.2 The new atmosphere model ICON
1.3 Research questions
2 Theoretical background
2.1 Fundamentals of atmospheric circulation
2.1.1 Primitive equations
2.1.2 The global energy budget
2.1.3 Baroclinic instability
2.1.4 Vertical structure of the atmosphere
2.2 Stratospheric dynamics
2.2.1 Circulation patterns
2.2.2 Atmospheric waves
2.2.3 Sudden stratospheric warmings
2.2.4 Quasi-biennial oscillation
2.3 Atmospheric Teleconnections
2.3.1 NAM, NAO and PNA
2.3.2 El Niño-Southern Oscillation
2.3.3 Arctic-midlatitude linkages
3 Atmospheric model and methods of analysis
3.1 Atmospheric model ICON-NWP
3.1.1 Model description
3.1.2 Experimental setup
3.2 Reanalysis data ERA-Interim
3.3 Methods of analysis
3.3.1 NAM index for stratosphere–troposphere coupling
3.3.2 Stratospheric warmings
3.3.3 ENSO index and composites
3.3.4 Bias and error estimation
3.3.5 Statistical significance
4 Results
4.1 Evaluation of seasonal experiments with ICON-NWP
4.1.1 Tropospheric circulation
4.1.2 Stratospheric circulation
4.2 Effect of gravity wave drag parameterisations
4.2.1 Stratospheric effects
4.2.2 Effects on stratosphere-troposphere coupling
4.2.3 Tropospheric effects
4.3 Low latitudinal influence on the stratospheric polar vortex
4.3.1 Quasi-biennial oscillation
4.3.2 El Niño-Southern Oscillation
4.4 Arctic-midlatitude linkages
4.4.1 Tropospheric processes
4.4.2 Stratospheric pathway
4.4.3 Sea ice sensitivity experiment
5 Discussion and outlook
Bibliography
Appendix
Location:
AWI Reading room
Branch Library:
AWI Library
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