Reductions in daily continental-scale atmospheric circulation biases between generations of global climate models: CMIP5 to CMIP6

Cannon, Alex J.

doi:10.1088/1748-9326/ab7e4f

Cited by 63 publications

(51 citation statements)

References 39 publications

(40 reference statements)

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“…1 of this study and Anstey et al (2013) over the Euro-Atlantic sector. Increasing horizontal resolution may also result in an overall improvement in representing the synoptic-scale atmospheric circulation (Cannon 2020) and associated linkages between blocking and cold temperature extremes over the Pacific-North America. This study identifies blocking events using the meridional gradients of 500 hPa geopotential heights; however, this approach has difficulty detecting omega-shaped blocking events that often occur in the Pacific region, and different blocking methods have their own strengths and weaknesses (Woollings et al 2018).…”

Section: Summary and Discussionmentioning

confidence: 99%

Links between atmospheric blocking and North American winter cold spells in two generations of Canadian Earth System Model large ensembles

Jeong

Cannon

2021

Clim Dyn

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Due to the significant negative consequences of winter cold extremes, there is need to better understand and simulate the mechanisms driving their occurrence. The impact of atmospheric blocking on winter cold spells over North America is investigated using ERA-Interim and NCEP-DOE-R2 reanalyses for 1981–2010. Initial-condition large-ensembles of two generations of Canadian Earth System Models (CanESM5 and its predecessor, CanESM2) are evaluated in terms of their ability to represent the blocking-cold spell linkage and the associated internal-variability. The reanalysis datasets show that 72 and 58% of cold spells in southern and northern North America coincide with blocking occurring in the high-latitude Pacific-North America. Compared to the two reanalyses, CanESM2 and CanESM5 ensembles underestimate by 19.9 and 14.3% cold spell events coincident with blocking, due to significant under-representation of blocking frequency over the North Pacific (− 47.1 and − 29.0%), whereas biases in cold spell frequency are relatively small (6.6 and − 4.7%). In the reanalyses, regions with statistically significant above-normal cold spell frequency relative to climatology lie on the east and/or south flanks of blocking events, whereas those with below-normal frequency lie along the core or surrounding the blocking. The two ensembles reproduce the observed blocking-cold spell linkage over North America, despite underestimating the magnitude of blocking frequency. The two ensembles also reproduce the physical drivers that underpin the blocking-cold spell linkage. Spatial agreement with the reanalyses is found in the simulated patterns of temperature advection and surface heat flux forcing anomalies during blocking events. While CanESM5 shows an improved representation of the blocking climatology relative to CanESM2, both yield similar results in terms of the blocking-cold spell linkage and associated internal-variability.

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Section: Summary and Discussionmentioning

confidence: 99%

Links between atmospheric blocking and North American winter cold spells in two generations of Canadian Earth System Model large ensembles

Jeong

Cannon

2021

Clim Dyn

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“…Previous studies that analysed the performance capabilities of CMIP5 and CMIP6 GCMs have suggested that CMIP6 GCM represents an improvement over the previous versions (Song et al ., 2021; Wu et al ., 2019; Xin et al, 2020). In particular, Cannon (2020) evaluated simulations of daily sea‐level pressure circulation using the CMIP5 GCM and corresponding newer versions in CMIP6. As a result, it was found that the global error of the CMIP6 model was reduced by 24% compared with the previous version.…”

Section: Discussionmentioning

confidence: 99%

Spatiotemporal differences and uncertainties in projections of precipitation and temperature in South Korea from CMIP6 and CMIP5 general circulation models

Song

Chung

Shahid

2021

Intl Journal of Climatology

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This study compared the historical simulations and future projections of precipitation and temperature of Coupled Model Intercomparison Project (CMIP)5 and CMIP6 general circulation models (GCMs) to quantify the differences in the projections due to differences in scenarios. Five performance indicators were used to quantify the model reproducibility of the observed precipitation levels at 22 stations for the historical period of 1970–2005. The percentages of change in precipitation and temperature were estimated for the near (2025–2060) and far future (2065–2100) for two Representative Concentration Pathway (RCP)4.5 and RCP8.5 scenarios of CMIP5 and two Shared Socioeconomic Pathway (SSP)2–4.5 and SSP5‐8.5 scenarios of CMIP6. The uncertainty in the projection in each case was calculated using the reliability ensemble average (REA) method. As a result, the CMIP6 GCMs showed an improvement compared with the CMIP5 GCMs with regard to the ability to simulate the historical climate. The uncertainty in the precipitation projections was higher for SSPs than that in RCPs. With regard to the temperature, the uncertainty was higher for RCPs than for SSPs. The ensemble means of the precipitation and temperature showed higher changes in the far future compared with the near future for both RCPs and SSPs. This study contributes to improvement in the confidence of future projections using CMIP6 GCMs and bolsters our understanding of the relative uncertainty in SSPs and RCPs.

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“…This can be done to investigate circulation biases in multi-model ensembles (e.g. Huth, 2000;Pastor and Casado, 2012;Stryhal and Huth, 2019;Cannon, 2020) as well as to identify possible changes in largescale circulation under future climate change scenarios (e.g. Belleflamme et al, 2013;Riediger and Gratzki, 2014).…”

Section: Introductionmentioning

confidence: 99%

Impacts of Dynamical Downscaling on Circulation type Statistics: Potential added Value in the Euro-CORDEX Ensemble

Røste

Landgren

2021

Preprint

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Atmospheric circulation type classification methods were applied to an ensemble of 57 regional climate model simulations from Euro-CORDEX, their 11 boundary models from CMIP5 and the ERA5 reanalysis. We compared frequencies of the different circulation types in the simulations with ERA5 and found that the regional models add value especially in the summer season. We applied three different classification methods (the subjective Grosswettertypes and the two optimisation algorithms SANDRA and distributed k-means clustering) from the cost733class software and found that the results are not particularly sensitive to choice of circulation classification method. There are large differences between models. Simulations based on MIROC-MIROC5 and CNRM-CERFACS-CNRM-CM5 show an over-representation of easterly flow and an under-representation of westerly. The downscaled results retain the large-scale circulation from the global model most days, but especially the regional model IPSL-WRF381P changes the circulation more often, which increases the error relative to ERA5. Simulations based on ICHEC-EC-EARTH and MPI-M-MPI-ESM-LR show consistently smaller errors relative to ERA5 in all seasons. The ensemble spread is largest in the summer and smallest in the winter. Under the future RCP8.5 scenario, more than half of the ensemble shows an increase in frequency of north-easterly flow and decrease in the Central-Eastern European high and south-easterly flow. There is in general a strong agreement in the sign of the change between the regional simulations and the data from the corresponding global model.

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Reductions in daily continental-scale atmospheric circulation biases between generations of global climate models: CMIP5 to CMIP6

Cited by 63 publications

References 39 publications

Links between atmospheric blocking and North American winter cold spells in two generations of Canadian Earth System Model large ensembles

Links between atmospheric blocking and North American winter cold spells in two generations of Canadian Earth System Model large ensembles

Spatiotemporal differences and uncertainties in projections of precipitation and temperature in South Korea from CMIP6 and CMIP5 general circulation models

Impacts of Dynamical Downscaling on Circulation type Statistics: Potential added Value in the Euro-CORDEX Ensemble

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