A perturbed parameter ensemble of HadGEM3-GC3.05 coupled model projections: part 2: global performance and future changes

Yamazaki, Kiroku; Sexton, David M. H.; Rostron, John; McSweeney, C.; Murphy, James M.; Harris, Glen R.

doi:10.1007/s00382-020-05608-5

Cited by 38 publications

(49 citation statements)

References 90 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 15-member PPE was based on the GC3.05 configuration of the UK Met Office Global Coupled Model (Williams et al 2017), a fully coupled version of the UK Met Office model featuring atmosphere and land (Walters et al 2017), ocean (Storkey et al 2017), and sea ice (Ridley et al 2017) components. Perturbations and the process for constructing the PPE used in UKCP Global is discussed in Sexton et al (2021) and the performance of the PPE is discussed in Yamazaki et al (2021). The 13 CMIP5 models were selected representing 12 different modelling groups, including a previous configuration of the UK Met Office model, HadGEM2; the selection was based on work by McSweeney et al (2015), which is summarised in Murphy et al (2018).…”

Section: Ukcpmentioning

confidence: 99%

Investigation of future climate change over the British Isles using weather patterns

et al. 2021

View full text Add to dashboard Cite

For those involved in planning for regional and local scale changes in future climate, there is a requirement for climate information to be available in a context more usually associated with meteorological timescales. Here we combine a tool used in numerical weather prediction, the 30 weather patterns produced by the Met Office, which are already applied operationally to numerical weather prediction models, to assess changes in the UK Climate Projections (UKCP) Global ensemble. Through assessing projected changes in the frequency of the weather patterns at the end of the 21st Century, we determine that future changes in large-scale circulation tend towards an increase in winter of weather patterns associated with cyclonic and westerly wind conditions at the expense of more anticyclonic, settled/blocked weather patterns. In summer, the results indicate a shift towards an increase in dry settled weather types with a corresponding reduction in the wet and windy weather types. Climatologically this suggests a shift towards warmer, wetter winters and warmer, drier summers; which is consistent with the headline findings from the UK Climate Projections 2018. This paper represents the first evaluation of weather patterns analysis within UKCP Global. It provides a detailed assessment of the changes in these weather patterns through the 21st Century and how uncertainty in emissions, structural and perturbed parameters affects these results. We show that the use of these weather patterns in tandem with the UKCP projections is useful for future work investigating changes in a range of weather-related climate features such as extreme precipitation.

show abstract

Section: Ukcpmentioning

confidence: 99%

Investigation of future climate change over the British Isles using weather patterns

et al. 2021

View full text Add to dashboard Cite

show abstract

“…2. This set of 25 coupled variants was then filtered down to 20, with the 5 members excluded because their simulated climate was unrealistically cool by 1970, or because they suffered from numerical instabilities (Murphy et al 2018;Yamazaki et al 2021). 3.…”

Section: Experimental Designmentioning

confidence: 99%

Evaluation of a new 12 km regional perturbed parameter ensemble over Europe

et al. 2021

Self Cite

View full text Add to dashboard Cite

We evaluate a 12-member perturbed parameter ensemble of regional climate simulations over Europe at 12 km resolution, carried out as part of the UK Climate Projections (UKCP) project. This ensemble is formed by varying uncertain parameters within the model physics, allowing uncertainty in future projections due to climate modelling uncertainty to be explored in a systematic way. We focus on present day performance both compared to observations, and consistency with the driving global ensemble. Daily and seasonal temperature and precipitation are evaluated as two variables commonly used in impacts assessments. For precipitation we find that downscaling, even whilst within the convection-parameterised regime, generally improves daily precipitation, but not everywhere. In summer, the underestimation of dry day frequency is worse in the regional ensemble than in the driving simulations. For temperature we find that the regional ensemble inherits a large wintertime cold bias from the global model, however downscaling reduces this bias. The largest bias reduction is in daily winter cold temperature extremes. In summer the regional ensemble is cooler and wetter than the driving global models, and we examine cloud and radiation diagnostics to understand the causes of the differences. We also use a low-resolution regional simulation to determine whether the differences are a consequence of resolution, or due to other configuration differences, with the predominant configuration difference being the treatment of aerosols. We find that use of the EasyAerosol scheme in the regional model, which aims to approximate the aerosol effects in the driving model, causes reduced temperatures by around 0.5 K over Eastern Europe in Summer, and warming of a similar magnitude over France and Germany in Winter, relative to the impact of interactive aerosol in the global runs. Precipitation is also increased in these regions. Overall, we find that the regional model is consistent with the global model, but with a typically better representation of daily extremes and consequently we have higher confidence in its projections of their future change.

show abstract

“…Here we provide a summary description of the PPE. Further details, including a description of the GC3.05 base model, can be found in Yamazaki et al (2021).…”

Section: Base Model and Parameter Perturbationsmentioning

confidence: 99%

“…Further screening was applied to the variants run as fully coupled simulations. An initial ensemble of 25 members was reduced, first to 20 members and then to 15, based on criteria such as: numerical stability; the strength of the Atlantic meridional overturning circulation (AMOC); historical trends in northern hemisphere surface air temperatures; and climatological temperature biases (Yamazaki et al 2021).…”

Section: Base Model and Parameter Perturbationsmentioning

confidence: 99%

“…The PPE studied here is a 20-member ensemble of a very recent configuration of the Met Office's global coupled model, referred to as HadGEM3-GC3.05 (Yamazaki et al 2021), which fed into the recent UK Climate Projections for land project (UKCP18; Murphy et al 2018). The 20 members were generated through simultaneous perturbations made to 47 model parameters (across 7 atmospheric parameterisation schemes), chosen to sample key parametric uncertainties (see Section 2).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation and projections of the East Asian summer monsoon in a perturbed parameter ensemble

Rostron

Sexton

Furtado

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

The East Asian summer monsoon (EASM) is a dominant driver of East Asian climate, with variations in its strength potentially impacting the livelihoods of millions of people. Understanding, predicting and assessing uncertainties in these variations is therefore an important area of research. Here, we present a study of the projected 21st Century changes in the EASM using a ‘perturbed parameter ensemble’ (PPE) of HadGEM3-GC3.05 coupled climate models, which samples uncertainties arising from differences in model parameter values. We show that while the present-day performance of PPE members for leading order EASM metrics is comparable to CMIP5 models in many respects, the PPE also exposes model biases which exist for most, if not all, parameter combinations. These ‘structural’ model biases are found mainly in the low-level circulation over the South China Sea and west Pacific. We also show that future changes in regional circulation and precipitation are projected consistently across the PPE members. A more detailed moisture budget analysis of the precipitation changes in a region covering the Yangtze River valley shows that both dynamic and thermodynamic changes contribute to an increase in precipitation over the 21st century, but that the spread in this response across the PPE is mainly due to spread in the dynamic responses. We also discuss how the information provided by the PPE may be used in practice, considering the plausibility of the models, and giving examples of ways to sub-select ensemble members to capture the diversity in the moisture budget changes.

show abstract

A perturbed parameter ensemble of HadGEM3-GC3.05 coupled model projections: part 2: global performance and future changes

Cited by 38 publications

References 90 publications

Investigation of future climate change over the British Isles using weather patterns

Investigation of future climate change over the British Isles using weather patterns

Evaluation of a new 12 km regional perturbed parameter ensemble over Europe

Evaluation and projections of the East Asian summer monsoon in a perturbed parameter ensemble

Contact Info

Product

Resources

About