High-Resolution Modelling of Climate Variability : Using the CESM 1.0.4
Most climate models have a 1◦ (100 km) horizontal resolution. This resolution is too coarse to resolve mesoscale processes in the ocean: ocean eddies. An ocean eddy is characterised by a swirling and turbulent fluid. To resolve ocean eddies within a climate model, a horizontal resolution of 0.1◦ (10...
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Utrecht University
2021
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ftunivutrecht:oai:dspace.library.uu.nl:1874/401045 2023-07-23T04:21:52+02:00 High-Resolution Modelling of Climate Variability : Using the CESM 1.0.4 Westen, Renatus Maria van Dijkstra, H.A. 2021-03-01 image/pdf https://dspace.library.uu.nl/handle/1874/401045 en eng Utrecht University https://dspace.library.uu.nl/handle/1874/401045 info:eu-repo/semantics/OpenAccess Climate Physics Physical Oceanography High-resolution Modelling Climate Variability Natural Variability Ocean Eddies Sea-level projections Dissertation 2021 ftunivutrecht 2023-07-02T03:11:25Z Most climate models have a 1◦ (100 km) horizontal resolution. This resolution is too coarse to resolve mesoscale processes in the ocean: ocean eddies. An ocean eddy is characterised by a swirling and turbulent fluid. To resolve ocean eddies within a climate model, a horizontal resolution of 0.1◦ (10 km) is required. Climate models with a horizontal resolution of 1◦ and 0.1◦ are referred to as low-resolution models and high-resolution models, respectively. Ocean eddies are relevant to the ocean circulation as they stir the (upper) ocean and contribute to the transport of heat and salt. Model biases are reduced in climate simulations in which ocean eddies are explicitly resolved. In low-resolution climate models, eddy-related processes (transport and mixing) are parameterised at the cost of losing eddy characteristics within the model. As a result, the ocean circulation appears to be laminar in low-resolution climate models, sometimes referred to as the ‘honey ocean’. In this thesis, model output (300 years) of a high-resolution version of the Community Earth System Model (CESM) is analysed. We explore the following research questions in this thesis: 1) Is a high-resolution version of the CESM capable of capturing climate variability (sub-annual - multidecadal) as seen in observations? 2) Are sea-level projections different between the high-resolution CESM and low-resolution CESM? For the first research question, the analysis is restricted to the Caribbean Sea and the Southern Ocean. The simulated sub-annual ocean variability matches well with observations in the Caribbean Sea. This sub-annual variability is related to ocean eddies. Apart from sub-annual variability, multidecadal variability is found in the Caribbean Sea and surroundings in the high-resolution CESM. This multidecadal variability is induced by ocean eddies in the Southern Ocean and this variability propagates through the entire ocean circulation. From observations, it is known that multidecadal variability exists in the Southern Ocean. However, ... Doctoral or Postdoctoral Thesis Southern Ocean Utrecht University Repository Southern Ocean |
institution |
Open Polar |
collection |
Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
topic |
Climate Physics Physical Oceanography High-resolution Modelling Climate Variability Natural Variability Ocean Eddies Sea-level projections |
spellingShingle |
Climate Physics Physical Oceanography High-resolution Modelling Climate Variability Natural Variability Ocean Eddies Sea-level projections Westen, Renatus Maria van High-Resolution Modelling of Climate Variability : Using the CESM 1.0.4 |
topic_facet |
Climate Physics Physical Oceanography High-resolution Modelling Climate Variability Natural Variability Ocean Eddies Sea-level projections |
description |
Most climate models have a 1◦ (100 km) horizontal resolution. This resolution is too coarse to resolve mesoscale processes in the ocean: ocean eddies. An ocean eddy is characterised by a swirling and turbulent fluid. To resolve ocean eddies within a climate model, a horizontal resolution of 0.1◦ (10 km) is required. Climate models with a horizontal resolution of 1◦ and 0.1◦ are referred to as low-resolution models and high-resolution models, respectively. Ocean eddies are relevant to the ocean circulation as they stir the (upper) ocean and contribute to the transport of heat and salt. Model biases are reduced in climate simulations in which ocean eddies are explicitly resolved. In low-resolution climate models, eddy-related processes (transport and mixing) are parameterised at the cost of losing eddy characteristics within the model. As a result, the ocean circulation appears to be laminar in low-resolution climate models, sometimes referred to as the ‘honey ocean’. In this thesis, model output (300 years) of a high-resolution version of the Community Earth System Model (CESM) is analysed. We explore the following research questions in this thesis: 1) Is a high-resolution version of the CESM capable of capturing climate variability (sub-annual - multidecadal) as seen in observations? 2) Are sea-level projections different between the high-resolution CESM and low-resolution CESM? For the first research question, the analysis is restricted to the Caribbean Sea and the Southern Ocean. The simulated sub-annual ocean variability matches well with observations in the Caribbean Sea. This sub-annual variability is related to ocean eddies. Apart from sub-annual variability, multidecadal variability is found in the Caribbean Sea and surroundings in the high-resolution CESM. This multidecadal variability is induced by ocean eddies in the Southern Ocean and this variability propagates through the entire ocean circulation. From observations, it is known that multidecadal variability exists in the Southern Ocean. However, ... |
author2 |
Dijkstra, H.A. |
format |
Doctoral or Postdoctoral Thesis |
author |
Westen, Renatus Maria van |
author_facet |
Westen, Renatus Maria van |
author_sort |
Westen, Renatus Maria van |
title |
High-Resolution Modelling of Climate Variability : Using the CESM 1.0.4 |
title_short |
High-Resolution Modelling of Climate Variability : Using the CESM 1.0.4 |
title_full |
High-Resolution Modelling of Climate Variability : Using the CESM 1.0.4 |
title_fullStr |
High-Resolution Modelling of Climate Variability : Using the CESM 1.0.4 |
title_full_unstemmed |
High-Resolution Modelling of Climate Variability : Using the CESM 1.0.4 |
title_sort |
high-resolution modelling of climate variability : using the cesm 1.0.4 |
publisher |
Utrecht University |
publishDate |
2021 |
url |
https://dspace.library.uu.nl/handle/1874/401045 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
https://dspace.library.uu.nl/handle/1874/401045 |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1772188175159001088 |