scholarly journals CMIP5 multimodel ensemble projection of storm track change under global warming

2012 ◽  
Vol 117 (D23) ◽  
pp. n/a-n/a ◽  
Author(s):  
Edmund K. M. Chang ◽  
Yanjuan Guo ◽  
Xiaoming Xia
Keyword(s):  
Global Warming ◽  
Storm Track ◽  
Multimodel Ensemble

scholarly journals Influence of Northern Hemispheric Winter Warming on the Pacific Storm Track

2021 ◽  
Author(s):  
Hyung-Ju Park ◽  
Kwang-Yul Kim
Keyword(s):  
Heat Flux ◽  
Global Warming ◽  
Energy Conversion ◽  
Storm Track ◽  
The Arctic ◽  
Late Winter ◽  
Turbulent Heat ◽  
Early Winter ◽  
Eddy Heat Flux ◽  
Northern Hemispheric

AbstractEffect of global warming on the sub-seasonal variability of the Northern Hemispheric winter (NDJFM) Pacific storm-track (PST) activity has been investigated. Previous studies showed that the winter-averaged PST has shifted northward and intensified, which was explained in terms of energy exchange with the mean field. Effect of global warming exhibits spatio-temporal heterogeneity with predominance over the Arctic region and in the winter season. Therefore, seasonal averaging may hide important features on sub-seasonal scales. In this study, distinct sub-seasonal response in storm track activities to winter Northern Hemispheric warming is analyzed applying cyclostationary empirical orthogonal function analysis to ERA5 data. The key findings are as follows. Change in the PST is not uniform throughout the winter; the PST shifts northward in early winter (NDJ) and intensifies in late winter (FM). In early winter, the combined effect of weakened baroclinic process to the south of the climatological PST and weakened barotropic damping to the north is responsible for the northward shift. In late winter, both processes contribute to the amplification of the PST. Further, change in baroclinic energy conversion is quantitatively dominated by eddy heat flux, whereas axial tilting of eddies is primarily responsible for change in barotropic energy conversion. A close relationship between anomalous eddy heat flux and anomalous boundary heating, which is largely determined by surface turbulent heat flux, is also demonstrated.

scholarly journals Modulation of Atmospheric Response to North Pacific SST Anomalies under Global Warming: A Statistical Assessment

2012 ◽  
Vol 25 (19) ◽  
pp. 6554-6566 ◽  
Author(s):  
Bolan Gan ◽  
Lixin Wu
Keyword(s):  
Global Warming ◽  
North Pacific ◽  
Climate Model ◽  
Storm Track ◽  
Early Winter ◽  
The North ◽  
Basin Scale ◽  
Climate Model Simulations ◽  
The North Pacific ◽  
Sst Anomalies

Abstract In this study the modulation of ocean-to-atmosphere feedback over the North Pacific in early winter from global warming is investigated based on both the observations and multiple climate model simulations from a statistical perspective. It is demonstrated that the basin-scale atmospheric circulation displays an equivalent barotropic ridge in response to warm SST anomalies in the Kuroshio–Oyashio Extension (KOE) region. This warm SST–ridge response in early winter can be enhanced significantly by global warming, indicating a strengthening of air–sea coupling over the North Pacific. This enhancement is likely associated with the intensification of storm tracks and, in turn, the amplification of atmospheric transient eddy feedback in a warm climate, although the secular trend of enhanced storm-track activity over the North Pacific is suggested to be biased in reanalysis product.

Long-Term Trends of Extra-Tropical Cyclones in the Extended ERA5 Reanalysis

2021 ◽  
Author(s):  
Alexia Karwat ◽  
Christian L. E. Franzke ◽  
Richard Blender
Keyword(s):  
Global Warming ◽  
Tropical Cyclones ◽  
Storm Track ◽  
Propagation Speed ◽  
Life Cycles ◽  
Natural Variability ◽  
Change Point Analysis ◽  
Systematic Change ◽  
Data Sets

<p>Long-term reanalysis data sets are needed to determine the natural variability of extra-tropical cyclone tracks and for the assessment of the response to global warming. Using a systematic change-point analysis we provide evidence that the pre-satellite ERA5 data of the Backward Extension (ERA5-BE, covering 1950-1978) is highly compatible with the standard ERA5 (1979-2021) data sets. We observe that the joint ERA5 data from 1950 to 2021 is consistent in all storm-related quantities, allowing long-term studies. Despite the high inter-annual variability, a trend analysis suggests that the intensity of extra-tropical cyclones has increased significantly in the Northern Hemisphere from 1950 to 2021. The propagation speed of extra-tropical cyclones has notably decreased and the North Atlantic cyclone track, in particular, has shifted northward. Furthermore, the number of North Pacific storms increased significantly; these storms exhibit longer life cycles and travel larger distances, while they also grow more slowly. From 1979 to 2021 we find increases in wind gusts and cyclone-related precipitation. The central geopotential height, a measure for storminess, has decreased in both storm track areas. The observed changes originating from potential changes in the atmospheric circulation are the result of natural variability and anthropogenic global warming. Future storm adaptation planning should consider the observed increase in storm-related impacts.</p>

scholarly journals Mechanisms of Global Warming Impacts on Robustness of Tropical Precipitation Asymmetry

2008 ◽  
Vol 21 (21) ◽  
pp. 5585-5602 ◽  
Author(s):  
Pei-Hua Tan ◽  
Chia Chou ◽  
Jien-Yi Tu
Keyword(s):  
Global Warming ◽  
Water Vapor ◽  
Climate Model ◽  
Hadley Circulation ◽  
The Other ◽  
Multimodel Ensemble ◽  
Model Simulations ◽  
Tropical Precipitation ◽  
Precipitation Anomalies ◽  
Climate Model Simulations

Abstract Hemispherically and temporally asymmetric tropical precipitation responses to global warming are evaluated in 13 different coupled atmosphere–ocean climate model simulations. In the late boreal summer, hemispherical averages of the tropical precipitation anomalies from the multimodel ensemble show a strong positive trend in the Northern Hemisphere and a weak negative trend in the Southern Hemisphere. In the late austral summer, on the other hand, the trends are reversed. This implies that the summer hemisphere becomes wetter and the winter hemisphere becomes a little drier in the tropics. Thus, the seasonal range of tropical precipitation, differences between wet and dry seasons, is increased. Zonal averages of the precipitation anomalies from the multimodel ensemble also reveal a meridional movement, which basically follows the seasonal migration of the main convection zone. Similar asymmetric features can be found in all 13 climate model simulations used in this study. Based on the moisture budget analysis, the vertical moisture advection associated with mean circulation is the main contribution for the robustness of the asymmetric distribution of the tropical precipitation anomalies. Under global warming, tropospheric water vapor increases as the temperature rises and most enhanced water vapor is in the lower troposphere. The ascending motion of the Hadley circulation then transports more water vapor upward, that is, anomalous moisture convergence, and enhances precipitation over the main convection zones. On the other hand, the thermodynamic effect associated with the descending motion of the Hadley circulation, that is, anomalous moisture divergence, reduces the precipitation over the descending regions.

The Position of the Midlatitude Storm Track and Eddy-Driven Westerlies in Aquaplanet AGCMs

2010 ◽  
Vol 67 (12) ◽  
pp. 3984-4000 ◽  
Author(s):  
Jian Lu ◽  
Gang Chen ◽  
Dargan M. W. Frierson
Keyword(s):  
Global Warming ◽  
Coming Out ◽  
Storm Track ◽  
Lower Troposphere ◽  
Static Stability ◽  
Hadley Cell ◽  
Eddy Heat Flux ◽  
Circulation Regime ◽  
Wide Range ◽  
Single Jet

Abstract The sensitivity of the midlatitude storm track and eddy-driven wind to the sea surface temperature (SST) boundary forcing is studied over a wide range of perturbations using both simple and comprehensive general circulation models over aquaplanet lower boundary conditions. Under the single-jet circulation regime similar to the conditions of the present climate in the Northern Hemisphere winter or the Southern Hemisphere summer, the eddy-driven jet shifts monotonically poleward with both the global mean and the equator-to-pole gradient of the SST. The eddy-driven jet can have a reverse relationship to the gradient if it is well separated from the subtropical jet and Hadley cell boundary in a double-jet circulation regime. A simple scaling is put forward to interpret the simulated sensitivity of the storm-track/eddy-driven westerly wind position within the single-jet regime in both models. The rationale for the scaling is based on the notion that the wave activity flux can propagate horizontally away from the source region, resulting in a broader distribution of eddy potential vorticity (PV) flux in the upper troposphere than that of the flux in the opposite direction in the lower troposphere. As a consequence, the position of the maximum of the eddy-driven westerlies tends to be controlled by the profile of the relatively sharp-peaked low-level PV flux, which is dominated by the eddy heat flux component of the Eliassen–Palm (EP) flux. Thus, the position of the eddy-driven surface westerlies may be inferred from the vertical EP flux coming out of the lower troposphere. The vertical EP flux can be parameterized by a measure of baroclinicity, whose latitudinal variations show a linear relationship with the meridional displacement of the eddy-driven westerlies and the storm track. This relationship still holds well within the single-jet regime, even when only the variation of static stability is taken into consideration in estimating the baroclinicity (the temperature gradient component of which is fixed). To the extent that the static stability is deterministically constrained by and hence can be predicted from the given SST conditions through a moist scaling for the midlatitude stratification, one may, given SST perturbations, predict which way the storm track and eddy-driven wind should shift with respect to a chosen reference climate state. The resultant anomaly-wise scaling turns out to be valid for both the idealized and comprehensive models, regardless of the details in the model physics. By corollary, it can be argued that the poleward shift of storm track found in the global warming simulations by fully coupled climate models may be attributed, at least partially, to the increase in the subtropical and midlatitude static stability with global warming.

scholarly journals Simple Uncertainty Frameworks for Selecting Weighting Schemes and Interpreting Multimodel Ensemble Climate Change Experiments

2013 ◽  
Vol 26 (12) ◽  
pp. 4017-4037 ◽  
Author(s):  
Philip G. Sansom ◽  
David B. Stephenson ◽  
Christopher A. T. Ferro ◽  
Giuseppe Zappa ◽  
Len Shaffrey
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Storm Track ◽  
Future Climate Change ◽  
Climate Response ◽  
Multimodel Ensemble ◽  
Weighting Schemes ◽  
Climate Change Response ◽  
Change Response ◽  
Cyclone Frequency

Abstract Future climate change projections are often derived from ensembles of simulations from multiple global circulation models using heuristic weighting schemes. This study provides a more rigorous justification for this by introducing a nested family of three simple analysis of variance frameworks. Statistical frameworks are essential in order to quantify the uncertainty associated with the estimate of the mean climate change response. The most general framework yields the “one model, one vote” weighting scheme often used in climate projection. However, a simpler additive framework is found to be preferable when the climate change response is not strongly model dependent. In such situations, the weighted multimodel mean may be interpreted as an estimate of the actual climate response, even in the presence of shared model biases. Statistical significance tests are derived to choose the most appropriate framework for specific multimodel ensemble data. The framework assumptions are explicit and can be checked using simple tests and graphical techniques. The frameworks can be used to test for evidence of nonzero climate response and to construct confidence intervals for the size of the response. The methodology is illustrated by application to North Atlantic storm track data from the Coupled Model Intercomparison Project phase 5 (CMIP5) multimodel ensemble. Despite large variations in the historical storm tracks, the cyclone frequency climate change response is not found to be model dependent over most of the region. This gives high confidence in the response estimates. Statistically significant decreases in cyclone frequency are found on the flanks of the North Atlantic storm track and in the Mediterranean basin.

scholarly journals The Role of Tropical, Midlatitude, and Polar Cloud-Radiative Changes for the Midlatitude Circulation Response to Global Warming

2020 ◽  
Vol 33 (18) ◽  
pp. 7927-7943 ◽  
Author(s):  
Nicole Albern ◽  
Aiko Voigt ◽  
David W. J. Thompson ◽  
Joaquim G. Pinto
Keyword(s):  
Global Warming ◽  
Storm Track ◽  
Radiative Heating ◽  
Sea Surface ◽  
Relative Importance ◽  
Upper Troposphere ◽  
The Mean ◽  
The Impact ◽  
Circulation Changes

AbstractPrevious studies showed that global cloud-radiative changes contribute half or more to the midlatitude atmospheric circulation response to global warming. Here, we investigate the relative importance of tropical, midlatitude, and polar cloud-radiative changes for the annual-mean, wintertime, and summertime circulation response across regions in AMIP-like simulations. To this end, we study global warming simulations from the ICON model run with the cloud-locking method and prescribed sea surface temperatures, which isolate the impact of changes in atmospheric cloud-radiative heating. Tropical cloud changes dominate the global cloud impact on the 850 hPa zonal wind, jet strength, and storm track responses across most seasons and regions. For the jet shift, a more diverse picture is found. In the annual mean and DJF, tropical and midlatitude cloud changes contribute substantially to the poleward jet shift in all regions. The poleward jet shift is further supported by polar cloud changes across the Northern Hemisphere but not in the Southern Hemisphere. In JJA, the impact of regional cloud changes on the jet position is small, consistent with an overall small jet shift during this season. The jet shift can be largely understood via the anomalous atmospheric cloud-radiative heating in the tropical and midlatitude upper troposphere. The circulation changes are broadly consistent with the influence of cloud-radiative changes on upper-tropospheric baroclinicity and thus the mean potential energy available for conversion into eddy kinetic energy. Our results help to explain the jet response to global warming and highlight the importance of tropical and midlatitude cloud-radiative changes for this response.

scholarly journals Euro-Atlantic winter storminess and precipitation extremes under 1.5 °C versus 2 °C warming scenarios

2017 ◽  
Author(s):  
Monika J. Barcikowska ◽  
Scott J. Weaver ◽  
Frauke Feser ◽  
Simone Russo ◽  
Frederik Schenk ◽  
...  
Keyword(s):  
Global Warming ◽  
Regional Scale ◽  
Storm Track ◽  
Precipitation Extremes ◽  
Storm Tracks ◽  
Atlantic Region ◽  
Storm Activity ◽  
Wind Speeds ◽  
North East ◽  
The North

Abstract. Severe winter storms in combination with precipitation extremes pose a serious threat to Europe. Located at the south-east exit of the North Atlantic's storm track, European coastlines are directly exposed to impacts by high wind speeds, storm floods and coastal erosion. In this study we analyze potential changes in simulated winter storminess and extreme precipitation which may occur under 1.5 °C or 2 °C warming scenarios. Here we focus on a first simulation suite of the atmospheric model CAM5 performed within the HAPPI project and evaluate how changes of the horizontal model resolution impact the results regarding atmospheric pressure, storm tracks, wind speed and precipitation extremes. The comparison of CAM5 simulations with different resolution indicates that an increased horizontal resolution to 0.25° is not only refining regional-scale information, but also improves large-scale atmospheric circulation features over the Euro-Atlantic region. The zonal bias in SLP and wind fields, which is typically found in low-resolution models, is considerably reduced. This allows us to analyze potential changes in regional- to local-scale extreme wind speeds and precipitation in a more realistic way. Our analysis of the future response for the 2 °C warming scenario generally confirms previous model simulations suggesting a poleward shift and intensification of the meridional circulation the Euro-Atlantic region. Additional analysis suggests that this shift occurs mainly after exceeding the 1.5 °C global warming level, when the midltatitude jetstream manifests a strengthening north-eastward. At the same time, this north-east shift of the storm tracks allows an intensification and north-east expansion of the Azores high leading to a tendency of less precipitation across the Bay of Biscay and North Sea. Regions impacted by the strengthening of the midlatitude jet, such as the northwest coasts of British Isles, Scandinavia and the Norwegian Sea, and over the North Atlantic east from Newfoundland experience an increase in the mean as well as daily and sub daily precipitation and wind extremes and storminess suggesting an important influence of increasing storm activity in these regions in response to global warming.

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