Response of the Quasi‐Biennial Oscillation to a warming climate in global climate models

We compare the response of the quasi-biennial oscillation (QBO) to a warming&#160;climate in eleven atmosphere general circulation models that performed time-slice&#160;simulations for present-day, doubled,&#160; and&#160; quadrupled CO2 climates.&#160; No consistency was found among the models for the QBO period response, with the period&#160;decreasing by eight months in some models and lengthening by up to thirteen months in others in the doubled CO2&#160; simulations.&#160; In the&#160;quadruped CO2 simulations&#160; a reduction in QBO period of 14 months was found in some models, whereas in several others the tropical oscillation no longer resembled the present day QBO, although&#160;could still be identified in the deseasonalized zonal mean zonal wind timeseries.&#160; In contrast, all the models projected a decrease in the&#160; QBO&#160;amplitude in a warmer climate with the largest relative decrease&#160; near 60 hPa. In simulations with doubled and quadrupled CO2 the multi-model mean QBO amplitudes decreased by 36\% and 51\%, respectively. Across the&#160; models the differences in the QBO period response were most strongly&#160;related to how the gravity wave momentum flux entering the stratosphere and&#160;tropical vertical residual velocity responded to the increases&#160;in CO2 amounts. Likewise it was found that the robust decrease in QBO amplitudes was&#160;correlated across the models to changes in vertical residual velocity,&#160;parameterized gravity wave momentum fluxes, and to some degree the resolved upward wave flux.&#160; We argue that uncertainty in the representation of the parameterized gravity waves is the most likely cause&#160;of the spread among the eleven models in the QBO's response to climate change.

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Defining metrics of the Quasi-Biennial Oscillation in global climate models

Geoscientific Model Development ◽

10.5194/gmd-10-2157-2017 ◽

2017 ◽

Vol 10 (6) ◽

pp. 2157-2168 ◽

Cited By ~ 23

Author(s):

Verena Schenzinger ◽

Scott Osprey ◽

Lesley Gray ◽

Neal Butchart

Keyword(s):

Climate Models ◽

Climate Model ◽

Global Climate ◽

Coupled Model ◽

Dominant Mode ◽

Global Climate Models ◽

Mean Flow ◽

Quasi Biennial Oscillation ◽

Radiosonde Observation ◽

Biennial Oscillation

Abstract. As the dominant mode of variability in the tropical stratosphere, the Quasi-Biennial Oscillation (QBO) has been subject to extensive research. Though there is a well-developed theory of this phenomenon being forced by wave–mean flow interaction, simulating the QBO adequately in global climate models still remains difficult. This paper presents a set of metrics to characterize the morphology of the QBO using a number of different reanalysis datasets and the FU Berlin radiosonde observation dataset. The same metrics are then calculated from Coupled Model Intercomparison Project 5 and Chemistry-Climate Model Validation Activity 2 simulations which included a representation of QBO-like behaviour to evaluate which aspects of the QBO are well captured by the models and which ones remain a challenge for future model development.

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Defining metrics of the Quasi-Biennial Oscillation in global climate models

10.5194/gmd-2016-284 ◽

2016 ◽

Cited By ~ 3

Author(s):

Verena Schenzinger ◽

Scott Osprey ◽

Lesley Gray ◽

Neal Butchart

Keyword(s):

Climate Models ◽

Global Climate ◽

Model Development ◽

Dominant Mode ◽

Global Climate Models ◽

Mean Flow ◽

Quasi Biennial Oscillation ◽

Radiosonde Observation ◽

Intercomparison Project ◽

Biennial Oscillation

Abstract. As the dominant mode of variability in the tropical stratosphere, the Quasi-Biennial Oscillation (QBO) has been subject to extensive research. Though there is a well developed theory of this phenomenon being forced by wave-mean flow interaction, simulating the QBO adequately in global climate models (GCMs) still remains difficult. This paper presents a set of metrics to characterise the QBO using a number of different reanalysis datasets and the FU Berlin radiosonde observation dataset. The same metrics are then calculated from CMIP5 and CCMVal-2 intercomparison project simulations which included a representation of QBO like behaviour to evaluate which aspects of the QBO are well captured by the models and which ones remain a challenge for future model development.

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Evaluation of the Quasi-Biennial Oscillation in global climate models for the SPARC QBO-initiative

10.5194/egusphere-egu2020-17338 ◽

2020 ◽

Author(s):

Andrew Bushell ◽

Francois Lott ◽

Keyword(s):

General Circulation ◽

Climate Models ◽

Middle Atmosphere ◽

Global Climate ◽

Coupled Model ◽

Global Climate Models ◽

Multimodel Ensemble ◽

Quasi Biennial Oscillation ◽

Modelling Uncertainties ◽

Biennial Oscillation

The Stratosphere-troposphere Processes And their Role in Climate (SPARC) Quasi-Biennial Oscillation initiative (QBOi) seeks to improve confidence in general circulation and earth system model (GCM and ESM) simulations of the QBO, a prominent feature of middle atmosphere tropical variability first identified nearly sixty years ago. Although only five out of 47 models contributing to the Coupled Model Intercomparison Project Phase 5 (CMIP5) had spontaneous QBOs, simulated QBOs are anticipated to be more common among CMIP6 models as more atmospheric GCMs are able to reproduce the phenomenon, both by ensuring adequate vertical resolution in the stratosphere and by parametrizing accelerations due to subgrid nonorographic gravity waves (NOGWs). The complexity of CMIP6 models and their forcing scenarios, however, is an obstacle to using the CMIP6 multimodel ensemble for analysis of modelling uncertainties that are specific to the QBO and its impacts. The QBOi multimodel ensemble represents an alternative approach in which modelling uncertainties related to the QBO are assessed by performing coordinated experiments with atmospheric GCMs that have simplified external forcings and boundary conditions, designed to characterize QBO representation and its response to idealised future climate scenarios.&#160;Results are presented from an analysis of QBOs in thirteen atmospheric GCMs forced with both observed and annually repeating sea surface temperatures (SSTs). Mean QBO periods in most of these models are close to, though shorter than, the period of 28 months observed in ERA-Interim. Amplitudes are within &#177;20% of the observed QBO amplitude at 10hPa, but typically about half of that observed at lower altitudes (50 and 70hPa). For almost all models the oscillation's amplitude profile shows an overall upward shift compared to reanalysis and its meridional extent is too narrow. Asymmetry in the duration of eastward and westward phases is reasonably well captured though not all models replicate the observed slowing as the westward shear descends. Westward phases are generally too weak, and most models have an eastward time mean wind bias throughout the depth of the QBO. Intercycle period variability is realistic and in some models is enhanced in the experiment with observed SSTs compared to the experiment with repeated annual cycle SSTs. Mean periods are also sensitive to this difference between SSTs but only when parametrized NOGW sources are coupled to tropospheric parameters and not prescribed with a fixed value. But, overall, modelled QBOs are very similar whether or not the prescribed SSTs vary interannually. A portrait of the overall ensemble performance is provided by a normalised grading of QBO metrics. To simulate a QBO all but one model used parametrized NOGWs, which provided the majority of the total wave forcing at altitudes above 70hPa in most models. Thus the representation of NOGWs either explicitly or through parametrization is still a major uncertainty underlying QBO simulation in these present-day experiments.&#160;

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Future Australian Severe Thunderstorm Environments. Part II: The Influence of a Strongly Warming Climate on Convective Environments

Journal of Climate ◽

10.1175/jcli-d-13-00426.1 ◽

2014 ◽

Vol 27 (10) ◽

pp. 3848-3868 ◽

Cited By ~ 30

Author(s):

John T. Allen ◽

David J. Karoly ◽

Kevin J. Walsh

Keyword(s):

Climate Models ◽

Global Climate ◽

Convective Available Potential Energy ◽

Vertical Wind Shear ◽

Atmospheric Model ◽

Global Climate Models ◽

Historical Period ◽

Severe Thunderstorm ◽

Warming Climate ◽

Eastern Australia

Abstract The influence of a warming climate on the occurrence of severe thunderstorm environments in Australia was explored using two global climate models: Commonwealth Scientific and Industrial Research Organisation Mark, version 3.6 (CSIRO Mk3.6), and the Cubic-Conformal Atmospheric Model (CCAM). These models have previously been evaluated and found to be capable of reproducing a useful climatology for the twentieth-century period (1980–2000). Analyzing the changes between the historical period and high warming climate scenarios for the period 2079–99 has allowed estimation of the potential convective future for the continent. Based on these simulations, significant increases to the frequency of severe thunderstorm environments will likely occur for northern and eastern Australia in a warmed climate. This change is a response to increasing convective available potential energy from higher continental moisture, particularly in proximity to warm sea surface temperatures. Despite decreases to the frequency of environments with high vertical wind shear, it appears unlikely that this will offset increases to thermodynamic energy. The change is most pronounced during the peak of the convective season, increasing its length and the frequency of severe thunderstorm environments therein, particularly over the eastern parts of the continent. The implications of this potential increase are significant, with the overall frequency of potential severe thunderstorm days per year likely to rise over the major population centers of the east coast by 14% for Brisbane, 22% for Melbourne, and 30% for Sydney. The limitations of this approach are then discussed in the context of ways to increase the confidence of predictions of future severe convection.

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The MJO-QBO Relationship in a GCM with Stratospheric Nudging

Journal of Climate ◽

10.1175/jcli-d-20-0636.1 ◽

2021 ◽

pp. 1-69

Author(s):

Zane Martin ◽

Clara Orbe ◽

Shuguang Wang ◽

Adam Sobel

Keyword(s):

Climate Models ◽

Climate Model ◽

Global Climate ◽

Global Climate Model ◽

Global Climate Models ◽

Boreal Winter ◽

Quasi Biennial Oscillation ◽

Meridional Winds ◽

Goddard Institute ◽

Minimal Bias

AbstractObservational studies show a strong connection between the intraseasonal Madden-Julian oscillation (MJO) and the stratospheric quasi-biennial oscillation (QBO): the boreal winter MJO is stronger, more predictable, and has different teleconnections when the QBO in the lower stratosphere is easterly versus westerly. Despite the strength of the observed connection, global climate models do not produce an MJO-QBO link. Here the authors use a current-generation ocean-atmosphere coupled NASA Goddard Institute for Space Studies global climate model (Model E2.1) to examine the MJO-QBO link. To represent the QBO with minimal bias, the model zonal mean stratospheric zonal and meridional winds are relaxed to reanalysis fields from 1980-2017. The model troposphere, including the MJO, is allowed to freely evolve. The model with stratospheric nudging captures QBO signals well, including QBO temperature anomalies. However, an ensemble of nudged simulations still lacks an MJO-QBO connection.

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Air Temperature and Precipitation at Wolverine Glacier, Alaska; Glacier Growth in a Warmer, Wetter Climate

Annals of Glaciology ◽

10.1017/s0260305500008557 ◽

1990 ◽

Vol 14 ◽

pp. 191-194 ◽

Cited By ~ 15

Author(s):

L.R. Mayo ◽

R.S. March

Keyword(s):

Sea Level ◽

Air Temperature ◽

Climate Models ◽

Global Climate ◽

Global Climate Models ◽

Positive Mass ◽

Temperature And Precipitation ◽

Warming Climate ◽

The Common ◽

Snow Precipitation

Measurements at Wolverine Glacier, Alaska, from 1968 to 1988 indicate unsteady increases of air temperature and precipitation since the early 1970s. These increases were due almost entirely to changes in winter. Variations in annual temperature and precipitation at Wolverine Glacier and at Seward, a nearby climatological station at sea level, correlate positively with global temperature variations and are in general agreement with the changes at high latitudes predicted by five recent general atmospheric circulation models forced by anticipated rises of CO2. A consequence of the air temperature and precipitation increases at Wolverine Glacier was a change to a generally positive mass balance after 1976. Although these observations in the coastal maritime climate of Alaska run against the common, oversimplified notion that in a warming climate glaciers will melt, causing sea level to rise, they are logical and easily understood when the sensitivity of the glacier to the seasonal distribution of the changes is considered. The observed seasonal changes at Wolverine Glacier also are in agreement with global climate models. Snow precipitation and glacier accumulation increased, but at the same time warming affected only these those temperatures below about −5°C, and melting was not altered. The extent of this response is not well known, but the process may be taking place in other important glacierized regions.

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Air Temperature and Precipitation at Wolverine Glacier, Alaska; Glacier Growth in a Warmer, Wetter Climate

Annals of Glaciology ◽

10.3189/s0260305500008557 ◽

1990 ◽

Vol 14 ◽

pp. 191-194 ◽

Cited By ~ 5

Author(s):

L.R. Mayo ◽

R.S. March

Keyword(s):

Sea Level ◽

Air Temperature ◽

Climate Models ◽

Global Climate ◽

Global Climate Models ◽

Positive Mass ◽

Temperature And Precipitation ◽

Warming Climate ◽

The Common ◽

Snow Precipitation

Measurements at Wolverine Glacier, Alaska, from 1968 to 1988 indicate unsteady increases of air temperature and precipitation since the early 1970s. These increases were due almost entirely to changes in winter. Variations in annual temperature and precipitation at Wolverine Glacier and at Seward, a nearby climatological station at sea level, correlate positively with global temperature variations and are in general agreement with the changes at high latitudes predicted by five recent general atmospheric circulation models forced by anticipated rises of CO2.A consequence of the air temperature and precipitation increases at Wolverine Glacier was a change to a generally positive mass balance after 1976. Although these observations in the coastal maritime climate of Alaska run against the common, oversimplified notion that in a warming climate glaciers will melt, causing sea level to rise, they are logical and easily understood when the sensitivity of the glacier to the seasonal distribution of the changes is considered. The observed seasonal changes at Wolverine Glacier also are in agreement with global climate models. Snow precipitation and glacier accumulation increased, but at the same time warming affected only these those temperatures below about −5°C, and melting was not altered. The extent of this response is not well known, but the process may be taking place in other important glacierized regions.

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