Dynamical Properties of the North Atlantic Atmospheric Circulation in the Past 150 Years in CMIP5 Models and the 20CRv2c Reanalysis

Rodrigues, David L.; Alvarez-Castro, M. Carmen; Messori, Gabriele; Yiou, Pascal; Robin, Yoann; Faranda, Davide

doi:10.1175/jcli-d-17-0176.1

Cited by 40 publications

(44 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Over a full year there are therefore two positive and two negative peaks in autocorrelation, with the second positive peak typically displaying a larger magnitude than the first. This is consistent with previous analyses which have identified a strong seasonal dependence in d Rodrigues et al, 2017). The presence of a semi-annual cycle leads us to interpret the ACF as being modulated by the four seasons, with the first positive peak corresponding to cross-season correlation and the second, larger, peak corresponding to correlation between the same seasons in successive years.…”

Section: Datasupporting

confidence: 91%

Dynamical properties and extremes of Northern Hemisphere climate fields over the past 60 years

Faranda

Messori

Alvarez-Castro

et al. 2017

Nonlin. Processes Geophys.

Self Cite

View full text Add to dashboard Cite

Abstract. Atmospheric dynamics are described by a set of partial differential equations yielding an infinite-dimensional phase space. However, the actual trajectories followed by the system appear to be constrained to a finite-dimensional phase space, i.e. a strange attractor. The dynamical properties of this attractor are difficult to determine due to the complex nature of atmospheric motions. A first step to simplify the problem is to focus on observables which affect -or are linked to phenomena which affect -human welfare and activities, such as sea-level pressure, 2 m temperature, and precipitation frequency. We make use of recent advances in dynamical systems theory to estimate two instantaneous dynamical properties of the above fields for the Northern Hemisphere: local dimension and persistence. We then use these metrics to characterize the seasonality of the different fields and their interplay. We further analyse the large-scale anomaly patterns corresponding to phase-space extremes -namely time steps at which the fields display extremes in their instantaneous dynamical properties. The analysis is based on the NCEP/NCAR reanalysis data, over the period 1948-2013. The results show that (i) despite the high dimensionality of atmospheric dynamics, the Northern Hemisphere sea-level pressure and temperature fields can on average be described by roughly 20 degrees of freedom; (ii) the precipitation field has a higher dimensionality; and (iii) the seasonal forcing modulates the variability of the dynamical indicators and affects the occurrence of phase-space extremes. We further identify a number of robust correlations between the dynamical properties of the different variables.

show abstract

Section: Datasupporting

confidence: 91%

Dynamical properties and extremes of Northern Hemisphere climate fields over the past 60 years

Faranda

Messori

Alvarez-Castro

et al. 2017

Nonlin. Processes Geophys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Second, we computed the local dimension of the observed Z500 sequence in CMIP5 RCP4.5 and RCP8.5 simulations. This assumes that the observed state belongs to the climate variability described by climate models, which is validated by the fact that the distribution of analog distances for each model is similar to the NCEP reanalysis distances (Rodrigues et al 2018). The local dimension informs on the number of degrees of freedom of trajectories around a given state and hence on its predictability (Faranda et al 2017).…”

Section: Changes In Atmospheric Circula-tionmentioning

confidence: 97%

Analyses of the Northern European Summer Heatwave of 2018

Yiou

Cattiaux

Faranda

et al. 2020

Bulletin of the American Meteorological Society

Self Cite

View full text Add to dashboard Cite

“…atmospheric rivers driving storm surges and river flooding); iv) spatio-temporal shifts in the distribution of multi-hazards and v) the application of multivariate extreme value statistics (e.g. and dynamical systems theory (De Luca et al, 2019b;Faranda et al, 2017bFaranda et al, , 2017aHochman et al, 2019;Lucarini et al, 2016Lucarini et al, , 2012Messori et al, 2017;Rodrigues et al, 2018) to climate projections (Faranda et al, 2019). Such research efforts could also focus on different spatial scales, from cities, to countries, continents and global areas.…”

Section: Concluding Remarks About Multi-hazardsmentioning

confidence: 99%

Concurrent Hydroclimatic Hazards from Catchment to Global Scales

Luca¹

2020

Preprint

View full text Add to dashboard Cite

Interactions between multiple hazards can cause socio-economic damages that exceed those expected by the individual hazard components. Over the past decade, the multi-hazards paradigm has emerged to the extent that the Sendai Framework for Disaster Risk Reduction 2015-2030 advocated a multi-hazard approach. This thesis examines three types of concurrent hydroclimatic hazards that can occur at catchment to global scales. The first multi-hazard is the link between multi-basin flooding (MBF) and extra-tropical cyclones (ETCs) over Great Britain during the period 1975-2014. Results show that during the most geographically widespread MBF episode, up to 108 river catchments (or ~46% of the study area) recorded a peak flow annual maximum within a 16-day window. Most extreme MBF episodes were linked to cyclonic Lamb Weather Types (LWTs), atmospheric rivers and very severe gales. These episodes were associated with significant socio-economic impacts due to widespread flooding. The second hazard was observed (1971-2000) and projected (2011-2100) LWTs, whose seasonal frequency and persistence are associated with multi-hazards over the British Isles. Daily sea-level-pressure data from two reanalyses products, one subjective weather pattern catalogue and an ensemble of 10 Atmosphere-Ocean General Circulation Models (AOGCMs) were used to compute LWTs. Results showed that the AOGCMs are overall able to reproduce historical weather pattern persistence, which, along with annual frequency, is projected to significantly increase anticyclonic and decrease cyclonic LWTs, in summer and autumn respectively. This implies a higher risk of drought, heatwaves and air pollution events in summer but reduced likelihood of flooding and severe gales in autumn by the end of the 21st century. By 2100, the AOGCMs suggest an increased risk of concurrent flood-wind hazards during winter. In summer, the strength of the nocturnal Urban Heat Island (UHI) of London is expected to intensify by the end of the century, contributing to higher chances of combined heatwave-air pollution events. The third type of multi-hazard investigated was the spatio-temporal concurrence of global wet and dry hydrological extremes, during the 1950-2014 period. The analysis was conducted using the monthly self-calibrated Palmer Drought Severity Index based on the Penman-Monteith model (sc_PDSI_pm). Results showed that the land area impacted by extreme dry and wet-dry events significantly increased over the observational period. The most geographically widespread wet-dry event covered a total area of 21 million km2 (or 14% of the global land area) with documented flood and drought impacts over diverse regions. Two new metrics were developed to provide more insight into the combined wet and dry hazards: the wet-dry (WD) ratio and the extreme transitions (ET) time interval. The former quantifies the predominance of wet or dry extremes over a given area, whereas the ET measures the average separation time between the opposite extremes (i.e. between wet to dry or dry to wet transitions). The WD-ratio reveals a predominance of wet over dry extremes in the USA, northern and southern south America, northern Europe, north Africa, western China and most of Australia. The ET median for wet to dry is ~27 months, and 21 months for dry to wet. Global correlations between wet-dry hydrological extremes and El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and American Multidecadal Oscillation (AMO) were also investigated. ENSO and PDO showed similar correlation patterns, with the former significantly impacting a larger area. On the other hand, the AMO showed an almost inverse spatial correlation pattern, with an overall larger area impacted. The findings presented in this thesis could be informative for emergency responders and relief agencies, disaster risk reduction practitioners, and (re)insurance companies. For instance, multi-basin flooding co-occurring with ETCs could overwhelm emergency response that depends on support from neighbouring regions that are similarly affected. Economic damages could exceed those insured by households and businesses. Projected rises in nocturnal UHI intensity in London could exacerbate heat-stress and, when combined with episodes of poor air quality, increase the likelihood of health problems amongst vulnerable groups. Furthermore, concurrent wet and dry hydrological extremes could be significant for organizations with global assets or sensitive supply chains, and the hydropower, agricultural and transport sectors. Global maps generated of major wet-dry events and the WD-ratio could also be integrated into a seasonal forecasting product, to help stakeholders in hedging the risk. Key opportunities for further research on multi-hazards are future hydroclimatic projections in the light of anthropogenic climate change and the application of new statistical techniques that could help in discerning the driving physical processes.

show abstract

Dynamical Properties of the North Atlantic Atmospheric Circulation in the Past 150 Years in CMIP5 Models and the 20CRv2c Reanalysis

Cited by 40 publications

References 37 publications

Dynamical properties and extremes of Northern Hemisphere climate fields over the past 60 years

Dynamical properties and extremes of Northern Hemisphere climate fields over the past 60 years

Analyses of the Northern European Summer Heatwave of 2018

Concurrent Hydroclimatic Hazards from Catchment to Global Scales

Contact Info

Product

Resources

About