Stephen Thomson

University of Exeter | UoE · College of Engineering, Mathematics and Physical Sciences

Arctic amplification has been proposed to promote temperature extremes by slowing the midlatitude jet and increasing the amplitude of its meanders. Observational and modeling studies have used a variety of metrics to quantify jet waviness. These studies show conflicting changes in jet waviness depending on the metric used and period examined. Here,...

Plain Language Summary Winter weather in the midlatitudes of the northern and southern hemispheres is influenced by the position of the jet streams. In a warming climate, the jet streams may move from the current average location. Past work has suggested that sea‐ice loss and ocean warming affect the jet stream location in opposite directions, lead...

Saturn’s largest moon, Titan, has an Earth-like volatile cycle, but with methane playing the role of water and surface liquid reservoirs geographically isolated at high latitudes. We recreate Titan’s characteristic dry hydroclimate at the equator of an Earth-like climate model without seasons and with water as the condensable by varying a small set...

Saturn's largest moon, Titan, has an Earth-like volatile cycle, but with methane playing the role of water and surface liquid reservoirs geographically isolated at high latitudes. We recreate Titan's characteristic dry hydroclimate at the equator of an Earth-like climate model without seasons and with water as the condensable by varying a small set...

The Bristol CMIP6 Data Hackathon formed part of the Met Office Climate Data Challenge Hackathon series during 2021, bringing together around 100 UK early career researchers from a wide range of environmental disciplines. The purpose was to interrogate the under‐utilised but currently most advanced climate model inter‐comparison project datasets to...

Among the great diversity of atmospheric circulation patterns observed throughout the solar system, polar vortices stand out as a nearly ubiquitous planetary‐scale phenomenon. In recent years, there have been significant advances in the observation of planetary polar vortices, culminating in the fascinating discovery of Jupiter's polar vortex clust...

The winter polar vortices on Mars are annular in their potential vorticity (PV) structure, a phenomenon identified in observations, reanalysis, and some numerical simulations. Some recent modeling studies have proposed that condensation of atmospheric carbon dioxide at the winter pole is a contributing factor to maintaining the annulus through the...

A simple diagnostic cloud scheme (SimCloud) for general circulation models (GCMs), which has a modest level of complexity and is transparent in describing its dependence on tunable parameters, is proposed in this study. The large-scale clouds, which form the core of the scheme, are diagnosed from relative humidity. In addition, the marine low strat...

The winter polar vortices on Mars are annular in terms of their potential vorticity (PV) structure, a phenomenon identified in observations, reanalysis and some numerical simulations. Some recent modeling studies have proposed that condensation of atmospheric carbon dioxide at the winter pole is a contributing factor to maintaining the annulus thro...

SimCloud, a simple diagnostic cloud scheme for general circulation models (GCMs) is proposed in this study. The large-scale clouds, which form the core of the scheme, are diagnosed from relative humidity. In addition, marine low stratus clouds, typically found off the west coast of continents over subtropical oceans, are determined largely as a fun...

Skill in seasonal forecasts in the Northern Hemisphere extratropics is mostly limited to winter. Drivers of summer circulation anomalies over the North Atlantic–European (NAE) sector are poorly understood. Here, we investigate the role of North Atlantic sea surface temperatures (SSTs) in driving summer atmospheric circulation changes. The summer No...

The depth of the jet streams seen in Jupiter's outer weather layer has long been debated, with alternative suggestions of confinement to the weather layer, and extensions deep into the planet being considered. Interpretation of measurements from NASA's Juno probe have suggested that the weather‐layer jets do extend deep into the planet down to dept...

We describe the use of Isca for the hierarchical modeling of Solar System planets, with particular attention paid to Earth, Mars, and Jupiter. Isca is a modeling framework for the construction and use of models of planetary atmospheres at varying degrees of complexity, from featureless model planets with an atmosphere forced by a thermal relaxation...

The climate and circulation of a terrestrial planet are governed by, among other things, the distance to its host star, its size, rotation rate, obliquity, atmospheric composition and gravity. Here we explore the effects of the last of these, the Newtonian gravitational acceleration, on its atmosphere and climate. We first demonstrate that if the a...

The climate and circulation of a terrestrial planet are governed by, among other things, the distance to its host star, its size, rotation rate, obliquity, atmospheric composition and gravity. Here we explore the effects of the last of these, the Newtonian gravitational acceleration, on its atmosphere and climate. We first demonstrate that if the a...

In this paper and its companion, Part I, we explore the response of the atmosphere to sea surface temperature anomalies in different geographical locations and seasons. In Part I, we focused on Northern Hemisphere winter (DJF), whereas in this paper, Part II, we focus on summer (JJA) and interseasonal comparisons. We use two different configuration...

The atmospheric response to SST anomalies is notoriously difficult to simulate and may be sensitive to model details and biases, particularly in midlatitudes. Studies have suggested that the response is particularly sensitive to a model's background wind field and its variability. The dependence on such factors has meant that it is difficult to kno...

Isca is a framework for the idealized modelling of the global circulation of planetary atmospheres at varying levels of complexity and realism. The framework is an outgrowth of models from the Geophysical Fluid Dynamics Laboratory in Princeton, USA, designed for Earth's atmosphere, but it may readily be extended into other planetary regimes. Variou...

Isca is a framework for the idealized modelling of the global circulation of planetary atmospheres at varying levels of complexity and realism. The framework is an outgrowth of models from the Geophysical Fluid Dynamics Laboratory designed for Earth's atmosphere, but it may readily be extended into other planetary regimes. Various forcing and radia...

A longstanding mystery about Jupiter has been the straightness and steadiness of its weather-layer jets, quite unlike terrestrial strong jets with their characteristic unsteadiness and long-wavelength meandering. The problem is addressed in two steps. The first is to take seriously the classic Dowling-Ingersoll $1\hspace{-2pt}\frac{1}{2}$-layer sce...

Polar vortices on Mars provide case studies to aid understanding of geophysical vortex dynamics and may help to resolve long-standing issues regarding polar vortices on Earth. Due to the recent development of the first publicly available Martian reanalysis data set (MACDA), we are able to, for the first time, thoroughly characterise the structure a...

A longstanding mystery about Jupiter has been the straightness of real Jovian jets, quite unlike terrestrial strong jets with their characteristic long-wavelength meandering. The problem is addressed in two steps. The first is to take seriously the classic Ingersoll-Cuong [4], Dowling-Ingersoll [1] and Stamp-Dowling [12] scenarios, with deep zonal...