A westward shift in tropical cyclone potential intensity and genesis regions in the North Atlantic during the Last Interglacial

Author(s):  
Qing Yan ◽  
Robert Korty ◽  
Ting Wei ◽  
Nanxuan Jiang
2014 ◽  
Vol 29 (3) ◽  
pp. 505-516 ◽  
Author(s):  
Elizabeth A. Ritchie ◽  
Kimberly M. Wood ◽  
Oscar G. Rodríguez-Herrera ◽  
Miguel F. Piñeros ◽  
J. Scott Tyo

Abstract The deviation-angle variance technique (DAV-T), which was introduced in the North Atlantic basin for tropical cyclone (TC) intensity estimation, is adapted for use in the North Pacific Ocean using the “best-track center” application of the DAV. The adaptations include changes in preprocessing for different data sources [Geostationary Operational Environmental Satellite-East (GOES-E) in the Atlantic, stitched GOES-E–Geostationary Operational Environmental Satellite-West (GOES-W) in the eastern North Pacific, and the Multifunctional Transport Satellite (MTSAT) in the western North Pacific], and retraining the algorithm parameters for different basins. Over the 2007–11 period, DAV-T intensity estimation in the western North Pacific results in a root-mean-square intensity error (RMSE, as measured by the maximum sustained surface winds) of 14.3 kt (1 kt ≈ 0.51 m s−1) when compared to the Joint Typhoon Warning Center best track, utilizing all TCs to train and test the algorithm. The RMSE obtained when testing on an individual year and training with the remaining set lies between 12.9 and 15.1 kt. In the eastern North Pacific the DAV-T produces an RMSE of 13.4 kt utilizing all TCs in 2005–11 when compared with the National Hurricane Center best track. The RMSE for individual years lies between 9.4 and 16.9 kt. The complex environment in the western North Pacific led to an extension to the DAV-T that includes two different radii of computation, producing a parametric surface that relates TC axisymmetry to intensity. The overall RMSE is reduced by an average of 1.3 kt in the western North Pacific and 0.8 kt in the eastern North Pacific. These results for the North Pacific are comparable with previously reported results using the DAV for the North Atlantic basin.


2018 ◽  
Vol 146 (4) ◽  
pp. 1133-1155 ◽  
Author(s):  
Michael S. Fischer ◽  
Brian H. Tang ◽  
Kristen L. Corbosiero ◽  
Christopher M. Rozoff

The relationship between tropical cyclone (TC) convective characteristics and TC intensity change is explored using infrared and passive microwave satellite imagery of TCs in the North Atlantic and eastern North Pacific basins from 1989 to 2016. TC intensity change episodes were placed into one of four groups: rapid intensification (RI), slow intensification (SI), neutral (N), and weakening (W). To account for differences in the distributions of TC intensity among the intensity change groups, a normalization technique is introduced, which allows for the analysis of anomalous TC convective characteristics and their relationship to TC intensity change. A composite analysis of normalized convective parameters shows anomalously cold infrared and 85-GHz brightness temperatures, as well as anomalously warm 37-GHz brightness temperatures, in the upshear quadrants of the TC are associated with increased rates of TC intensification, including RI. For RI episodes in the North Atlantic basin, an increase in anomalous liquid hydrometeor content precedes anomalous ice hydrometeor content by approximately 12 h, suggesting convection deep enough to produce robust ice scattering is a symptom of, rather than a precursor to, RI. In the eastern North Pacific basin, the amount of anomalous liquid and ice hydrometeors increases in tandem near the onset of RI. Normalized infrared and passive microwave brightness temperatures can be utilized to skillfully predict episodes of RI, as the forecast skill of RI episodes using solely normalized convective parameters is comparable to the forecast skill of RI episodes by current operational statistical models.


2020 ◽  
Vol 33 (3) ◽  
pp. 959-975
Author(s):  
Alexandria Downs ◽  
Chanh Kieu

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.


2016 ◽  
Vol 29 (18) ◽  
pp. 6727-6749 ◽  
Author(s):  
Young-Kwon Lim ◽  
Siegfried D. Schubert ◽  
Oreste Reale ◽  
Andrea M. Molod ◽  
Max J. Suarez ◽  
...  

Abstract Interannual variations in seasonal tropical cyclone (TC) activity (e.g., genesis frequency and location, track pattern, and landfall) over the Atlantic are explored by employing observationally constrained simulations with the NASA Goddard Earth Observing System, version 5 (GEOS-5), atmospheric general circulation model. The climate modes investigated are El Niño–Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), and the Atlantic meridional mode (AMM). The results show that the NAO and AMM can strongly modify and even oppose the well-known ENSO impacts, like in 2005, when a strong positive AMM (associated with warm SSTs and a negative SLP anomaly over the western tropical Atlantic) led to a very active TC season with enhanced TC genesis over the Caribbean Sea and a number of landfalls over North America, under a neutral ENSO condition. On the other end, the weak TC activity during 2013 (characterized by weak negative Niño index) appears caused by a NAO-induced positive SLP anomaly with enhanced vertical wind shear over the tropical North Atlantic. During 2010, the combined impact of the three modes produced positive SST anomalies across the entire low-latitudinal Atlantic and a weaker subtropical high, leading to more early recurvers and thus fewer landfalls despite enhanced TC genesis. The study provides evidence that TC number and track are very sensitive to the relative phases and intensities of these three modes and not just to ENSO alone. Examination of seasonal predictability reveals that the predictive skill of the three modes is limited over tropics to subtropics, with the AMM having the highest predictability over the North Atlantic, followed by ENSO and NAO.


2013 ◽  
Vol 26 (11) ◽  
pp. 3631-3643 ◽  
Author(s):  
Gabriele Villarini ◽  
Gabriel A. Vecchi

Abstract By considering the intensity, duration, and frequency of tropical cyclones, the power dissipation index (PDI) and accumulated cyclone energy (ACE) are concise metrics routinely used to assess tropical storm activity. This study focuses on the development of a hybrid statistical–dynamical seasonal forecasting system for the North Atlantic Ocean’s PDI and ACE over the period 1982–2011. The statistical model uses only tropical Atlantic and tropical mean sea surface temperatures (SSTs) to describe the variability exhibited by the observational record, reflecting the role of both local and nonlocal effects on the genesis and development of tropical cyclones in the North Atlantic basin. SSTs are predicted using a 10-member ensemble of the Geophysical Fluid Dynamics Laboratory Climate Model, version 2.1 (GFDL CM2.1), an experimental dynamical seasonal-to-interannual prediction system. To assess prediction skill, a set of retrospective predictions is initialized for each month from November to April, over the years 1981–2011. The skill assessment indicates that it is possible to make skillful predictions of ACE and PDI starting from November of the previous year: skillful predictions of the seasonally integrated North Atlantic tropical cyclone activity for the coming season could be made even while the current one is still under way. Probabilistic predictions for the 2012 North Atlantic tropical cyclone season are presented.


Nature ◽  
10.1038/36540 ◽  
1997 ◽  
Vol 390 (6656) ◽  
pp. 154-156 ◽  
Author(s):  
Jess F. Adkins§ ◽  
Edward A. Boyle ◽  
Lloyd Keigwin ◽  
Elsa Cortijo

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