Testing theories of baroclinic adjustment in the laboratory and in simple atmospheric models

Lead Research Organisation: University of Oxford
Department Name: Oxford Physics

Abstract

The state of the Earth's climate can be viewed as resulting from a delicate balance between radiative forcing processes and the dynamical response of the system as it seeks to transport heat across the planet. Recent research has tended to focus on quantifying the radiative forcing processes and their associated uncertainties, and various factors (including those human-induced) leading to changes in the climate. But radiative forcing primarily constrains the energy throughput of the climate system and only indirectly influences key climate variables such as the mean surface temperature. Climate variables are also strongly affected by how efficiently heat is redistributed across the planet by dynamical processes in the atmosphere and oceans. These are intrinsically nonlinear, and are affected by internal feedbacks that are still not well understood. This leaves open such fundamental questions as: what determines the mean lapse rate in the extra-tropical atmosphere, and what determines the thermal contrast in the atmosphere between equator and poles or continents and oceans?

In this project, therefore, we will study the relevant dynamical processes in numerical model simulations, based on the Met Office ENDGame dynamical core, (a) in a configuration representing a novel laboratory analogue of the mid-latitude climate system in a real fluid under carefully controlled conditions (currently being investigated experimentally in Prof. Read's group in Oxford), and (b) in simplified global atmospheric models subject to idealized radiative and boundary forcing. Numerical model simulations will be carried out and (for (a)) compared with detailed measurements of the flow and thermal structure in the Oxford experiments. This will enable us to determine the efficiency of heat transfer linking convective and baroclinic regions in order to determine how transport efficiency scales with key parameters and how the flow itself determines the mean static stability. We will also be able to assess the conditions under which fully developed turbulent energy cascades emerge or may be suppressed. This will then be investigated (in (b)) over a range of atmospheric conditions, resolutions and convective parameterizations in the full ENDGame model with idealized forcing.

Publications

10 25 50
 
Description Initial investigations involving two dimensional simulations of the experiment showed it to be comparable to previous annulus experiments as its behaviour followed similar mathematical laws. It also showed that the annulus demonstrates the phenomena it was designed to explore. This work was peer reviewed and published. Following this, the main key achievement thus far has been the development of the Met Office Unified Model to model lab experiments. This has expanded the model's capabilities and identified areas of improvement for the dynamical core so has been beneficial to the wider community using the model. The model is now ready to use to achieve the original objectives. The model has now been used to compare with lab experiments and simple atmospheric models which suggest some discrepancies due to model deficiencies but also that the lab experiment provides a useful analogue to a planetary atmosphere.
Exploitation Route The model which has been developed may be used by others wishing to model similar lab experiments and link their experiments to more realistic planetary atmosphere models. Issues identified with the model have been fixed and this will benefit the community using the model.
Sectors Environment

 
Description The Met Office model has been developed to model lab experiments. This benefits the model development and the community using it as it is tested outside of its comfort zone. This is a work in progress but further benefits will come as it may be used by others in the future and simulations using the model will identify issues with the model formulation.
First Year Of Impact 2018
Sector Environment
Impact Types Policy & public services

 
Title Annulus model within the UM 
Description The Unified Model used by the UK Met Office has been adapted to have the functionality required to model fluid dynamics experiments in the lab. 
Type Of Material Computer model/algorithm 
Year Produced 2019 
Provided To Others? No  
Impact Ability to test the operational model against lab data and hence potentially improve weather/climate forecasting. Provides a flexible model of lab experiments that may be used byfitire projects. 
 
Description Met Office 
Organisation Meteorological Office UK
Country United Kingdom 
Sector Public 
PI Contribution I have taken the lead role in developing the Met Office model.
Collaborator Contribution Significant financial contribution to studentship but I do not know the exact amount. Individual groups and Met Office colleagues have provided a lot of support in developing the model for modelling lab experiments.
Impact Developing the Met Office model.
Start Year 2015
 
Description School science fair 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Around 50 primary school pupils visited the physics department for a range of science fair style activities. We demonstrated a simpler version of our research experiment which provided a basis for children to come up with their own short projects back at school
Year(s) Of Engagement Activity 2018
 
Description Stargazing 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Stargazing is a full day science fair at Oxford University which is open to the public and has an astronomy/planetary science theme. Most visitors are families and both children and adults reported that they learned a lot and were more interested in the related science as a result.
Year(s) Of Engagement Activity 2016,2017,2018,2019
URL https://www2.physics.ox.ac.uk/events/2018/01/27/stargazing-oxford-2018