The recently suggested absence of an internal multidecadal oscillation in the North Atlantic has consequences for anticipating the future of marine ecosystems

AbstractVarious modeling and observational studies have suggested that tropical cyclone (TC) intensity tends to increase in the future due to projected warmer sea surface temperature (SST). This study examines the effects of the tropospheric stratification that could potentially offset the direct increase of TC intensity associated with the warmer SST. Using reanalysis datasets and TC records in the northwestern Pacific and the North Atlantic basins, it is shown that there exists a consistently negative correlation between the annually averaged TC intensity and the basinwide average of the tropospheric static stability. This negative correlation is more robust in the northwestern Pacific basin when using the TC lifetime maximum intensity but is somewhat less significant in the North Atlantic basin. Further separation of the troposphere into a lower (1000–500 hPa) and an upper layer (500–200 hPa) reveals that it is the upper-tropospheric static stability that plays a more dominant role in governing the TC intensity variability. The negating effects of a stable troposphere on TC intensity as found in this study suggest a partial offset of the projected increase in the TC potential intensity due to the future warmer SST. Thus, the tropospheric static stability is one of the key large-scale factors that need to be properly taken into account in studies of long-term TC intensity change.

Download Full-text

Statistical Projection of the North Atlantic Storm Tracks

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-17-0348.1 ◽

2019 ◽

Vol 58 (7) ◽

pp. 1509-1522 ◽

Cited By ~ 3

Author(s):

Kajsa M. Parding ◽

Rasmus Benestad ◽

Abdelkader Mezghani ◽

Helene B. Erlandsen

Keyword(s):

North Atlantic ◽

Geopotential Height ◽

Climate Model ◽

Global Climate ◽

Global Climate Model ◽

Storm Tracks ◽

Cmip5 Models ◽

The North ◽

The Future ◽

The North Atlantic

AbstractA method for empirical–statistical downscaling was adapted to project seasonal cyclone density over the North Atlantic Ocean. To this aim, the seasonal mean cyclone density was derived from instantaneous values of the 6-h mean sea level pressure (SLP) reanalysis fields. The cyclone density was then combined with seasonal mean reanalysis and global climate model projections of SLP or 500-hPa geopotential height to obtain future projections of the North Atlantic storm tracks. The empirical–statistical approach is computationally efficient because it makes use of seasonally aggregated cyclone statistics and allows the future cyclone density to be estimated from the full ensemble of available CMIP5 models rather than from a smaller subset. However, the projected cyclone density in the future differs considerably depending on the choice of predictor, SLP, or 500-hPa geopotential height. This discrepancy suggests that the relationship between the cyclone density and SLP, 500-hPa geopotential height, or both is nonstationary; that is, that the statistical model depends on the calibration period. A stationarity test based on 6-hourly HadGEM2-ES data indicated that the 500-hPa geopotential height was not a robust predictor of cyclone density.

Download Full-text

Large Marine Ecosystems of the North Atlantic. Changing States and Sustainability

Aquaculture ◽

10.1016/s0044-8486(02)00346-0 ◽

2002 ◽

Vol 214 (1-4) ◽

pp. 424-425

Author(s):

Sebastiaan J de Groot

Keyword(s):

North Atlantic ◽

Marine Ecosystems ◽

Large Marine Ecosystems ◽

The North ◽

The North Atlantic

Download Full-text

Tropical Cyclones in the UPSCALE Ensemble of High-Resolution Global Climate Models*

Journal of Climate ◽

10.1175/jcli-d-14-00131.1 ◽

2015 ◽

Vol 28 (2) ◽

pp. 574-596 ◽

Cited By ~ 90

Author(s):

Malcolm J. Roberts ◽

Pier Luigi Vidale ◽

Matthew S. Mizielinski ◽

Marie-Estelle Demory ◽

Reinhard Schiemann ◽

...

Keyword(s):

Tropical Cyclones ◽

North Atlantic ◽

Global Climate ◽

Future Climate ◽

Model Resolution ◽

Central Pacific ◽

The North ◽

The Future ◽

The North Atlantic ◽

The Impact

Abstract The U.K. on Partnership for Advanced Computing in Europe (PRACE) Weather-Resolving Simulations of Climate for Global Environmental Risk (UPSCALE) project, using PRACE resources, constructed and ran an ensemble of atmosphere-only global climate model simulations, using the Met Office Unified Model Global Atmosphere 3 (GA3) configuration. Each simulation is 27 years in length for both the present climate and an end-of-century future climate, at resolutions of N96 (130 km), N216 (60 km), and N512 (25 km), in order to study the impact of model resolution on high-impact climate features such as tropical cyclones. Increased model resolution is found to improve the simulated frequency of explicitly tracked tropical cyclones, and correlations of interannual variability in the North Atlantic and northwestern Pacific lie between 0.6 and 0.75. Improvements in the deficit of genesis in the eastern North Atlantic as resolution increases appear to be related to the representation of African easterly waves and the African easterly jet. However, the intensity of the modeled tropical cyclones as measured by 10-m wind speed remains weak, and there is no indication of convergence over this range of resolutions. In the future climate ensemble, there is a reduction of 50% in the frequency of Southern Hemisphere tropical cyclones, whereas in the Northern Hemisphere there is a reduction in the North Atlantic and a shift in the Pacific with peak intensities becoming more common in the central Pacific. There is also a change in tropical cyclone intensities, with the future climate having fewer weak storms and proportionally more strong storms.

Download Full-text

Projected Changes in the Occurrence of Extreme and Rogue Waves in Future Climate in the North Atlantic

Volume 3A: Structures, Safety and Reliability ◽

10.1115/omae2017-61795 ◽

2017 ◽

Author(s):

Odin Gramstad ◽

Elzbieta Bitner-Gregersen ◽

Erik Vanem

Keyword(s):

North Atlantic ◽

Wave Spectrum ◽

Wave Model ◽

Rogue Waves ◽

Wave Climate ◽

Future Climate ◽

The North ◽

Wave Parameters ◽

The Future ◽

The North Atlantic

We investigate the future wave climate in the North Atlantic with respect to extreme events as well as on wave parameters that have previously not been considered in much details in the perspective of wave climate change, such as those associated with occurrence of rogue waves. A number of future wave projections is obtained by running the third generation wave model WAM with wind input derived from several global circulation models. In each case the wave model has been run for the 30-year historical period 1971–2000 and the future period 2071–2100 assuming the two different future climate scenarios RCP 4.5 and RCP 8.5. The wave model runs have been carried out by the Norwegian Meteorological Institute in Bergen, and the climate model result are taken from The Coupled Model Intercomparison Project phase 5 - CMIP5. In addition to the standard wave parameters such as significant wave height and peak period the wave model runs provided the full two-dimensional wave spectrum. This has enabled the study of a larger set of wave parameters. The focus of the present study is the projected future changes in occurrence of extreme sea states and extreme and rogue waves. The investigations are limited to parameters related to this in a few selected locations in the North Atlantic. Our results show that there are large uncertainties in many of the parameters considered in this study, and in many cases the different climate models and different model scenarios provide contradicting results with respect to the predicted change from past to future climate. There are, however, some situations for which a clearer tendency is observed.

Download Full-text