scholarly journals West African Storm Tracks and Their Relationship to Atlantic Tropical Cyclones

2007 ◽  
Vol 20 (11) ◽  
pp. 2468-2483 ◽  
Author(s):  
Susanna B. Hopsch ◽  
Chris D. Thorncroft ◽  
Kevin Hodges ◽  
Anantha Aiyyer
Keyword(s):  
Tropical Cyclone ◽  
West Africa ◽  
Tropical Cyclones ◽  
Storm Track ◽  
Meridional Wind ◽  
Tropical Cyclone Activity ◽  
West African ◽  
Storm Tracks ◽  
Tropical Atlantic ◽  
Cyclone Activity

Abstract The automatic tracking technique used by Thorncroft and Hodges has been used to identify coherent vorticity structures at 850 hPa over West Africa and the tropical Atlantic in the 40-yr ECMWF Re-Analysis. The presence of two dominant source regions, north and south of 15°N over West Africa, for storm tracks over the Atlantic was confirmed. Results show that the southern storm track provides most of the storms that reach the main development region where most tropical cyclones develop. There exists marked seasonal variability in location and intensity of the storms leaving the West African coast, which may influence the likelihood of downstream intensification and longevity. There exists considerable year-to-year variability in the number of West African storm tracks, both in numbers over the land and continuing out over the tropical Atlantic Ocean. While the low-frequency variability is well correlated with Atlantic tropical cyclone activity, West African rainfall, and SSTs, the interannual variability is found to be uncorrelated with these. In contrast, variance of the 2–6-day-filtered meridional wind, which provides a synoptic-scale measure of African easterly wave activity, shows a significant, positive correlation with tropical cyclone activity at interannual time scales.

scholarly journals Tracking Scheme Dependence of Simulated Tropical Cyclone Response to Idealized Climate Simulations

2014 ◽  
Vol 27 (24) ◽  
pp. 9197-9213 ◽  
Author(s):  
Michael Horn ◽  
Kevin Walsh ◽  
Ming Zhao ◽  
Suzana J. Camargo ◽  
Enrico Scoccimarro ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
General Circulation ◽  
Climate Model ◽  
Circulation Model ◽  
General Circulation Models ◽  
Tropical Cyclone Activity ◽  
Model Data ◽  
Cyclone Activity ◽  
Sensitivity Testing

Abstract Future tropical cyclone activity is a topic of great scientific and societal interest. In the absence of a climate theory of tropical cyclogenesis, general circulation models are the primary tool available for investigating the issue. However, the identification of tropical cyclones in model data at moderate resolution is complex, and numerous schemes have been developed for their detection. The influence of different tracking schemes on detected tropical cyclone activity and responses in the Hurricane Working Group experiments is examined herein. These are idealized atmospheric general circulation model experiments aimed at determining and distinguishing the effects of increased sea surface temperature and other increased CO2 effects on tropical cyclone activity. Two tracking schemes are applied to these data and the tracks provided by each modeling group are analyzed. The results herein indicate moderate agreement between the different tracking methods, with some models and experiments showing better agreement across schemes than others. When comparing responses between experiments, it is found that much of the disagreement between schemes is due to differences in duration, wind speed, and formation-latitude thresholds. After homogenization in these thresholds, agreement between different tracking methods is improved. However, much disagreement remains, accountable for by more fundamental differences between the tracking schemes. The results indicate that sensitivity testing and selection of objective thresholds are the key factors in obtaining meaningful, reproducible results when tracking tropical cyclones in climate model data at these resolutions, but that more fundamental differences between tracking methods can also have a significant impact on the responses in activity detected.

The Track Integrated Kinetic Energy of Atlantic Tropical Cyclones

2013 ◽  
Vol 141 (7) ◽  
pp. 2383-2389 ◽  
Author(s):  
V. Misra ◽  
S. DiNapoli ◽  
M. Powell
Keyword(s):  
Tropical Cyclone ◽  
Kinetic Energy ◽  
Tropical Cyclones ◽  
Warm Pool ◽  
Equatorial Pacific ◽  
Interannual Variations ◽  
Tropical Atlantic ◽  
Cyclone Activity ◽  
Atlantic Warm Pool ◽  
Atlantic Tropical Cyclone

Abstract In this paper the concept of track integrated kinetic energy (TIKE) is introduced as a measure of seasonal Atlantic tropical cyclone activity and applied to seasonal variability in the Atlantic. It is similar in concept to the more commonly used accumulated cyclone energy (ACE) with an important difference that in TIKE the integrated kinetic energy (IKE) is accumulated for the life span of the Atlantic tropical cyclone. The IKE is, however, computed by volume integrating the 10-m level sustained winds of tropical strength or higher quadrant by quadrant, while ACE uses the maximum sustained winds only without accounting for the structure of the storm. In effect TIKE accounts for the intensity, duration, and size of the tropical cyclones. In this research, the authors have examined the seasonality and the interannual variations of the seasonal Atlantic TIKE over a period of 22 yr from 1990 to 2011. It is found that the Atlantic TIKE climatologically peaks in the month of September and the frequency of storms with the largest TIKE are highest in the eastern tropical Atlantic. The interannual variations of the Atlantic TIKE reveal that it is likely influenced by SST variations in the equatorial Pacific and in the Atlantic Oceans. The SST variations in the central equatorial Pacific are negatively correlated with the contemporaneous seasonal (June–November) TIKE. The size of the Atlantic warm pool (AWP) is positively correlated with seasonal TIKE.

Hurricane “Amanda”: Rediscovery of a Forgotten U.S. Civil War Florida Hurricane

2013 ◽  
Vol 94 (11) ◽  
pp. 1735-1742 ◽  
Author(s):  
M. Chenoweth ◽  
C. J. Mock
Keyword(s):  
United States ◽  
Civil War ◽  
Tropical Cyclone ◽  
Natural Disaster ◽  
Tropical Cyclones ◽  
Tropical Cyclone Activity ◽  
Cyclone Activity ◽  
Major Hurricane ◽  
The U.S ◽  
States History

Among the most unusual and unexpected hurricanes in United States history is the only hurricane to make landfall in the month of May. This recently rediscovered storm that struck northwest Florida on 28 May 1863 created a natural disaster in the area that became lost to history because it was embedded in a much larger and important manmade event—in this case, the U.S. Civil War. The authors document the arrival of this storm both historically and meteorologically and anachronistically name it “Hurricane Amanda” in honor of the Union ship driven ashore by the hurricane. The hurricane revealed deficiencies and strengths in combat readiness by both sides. Meteorologically, the storm nearly achieved major hurricane status at landfall and its absence from modern databases of tropical cyclone activity is a useful reminder to users of important gaps in our knowledge of tropical cyclones even in the best-sampled storm basins.

Revised Prediction of Seasonal Atlantic Basin Tropical Cyclone Activity from 1 August

2007 ◽  
Vol 22 (5) ◽  
pp. 937-949 ◽  
Author(s):  
Philip J. Klotzbach
Keyword(s):  
Tropical Cyclone ◽  
Tropical Meteorology ◽  
Tropical Cyclone Activity ◽  
West African ◽  
Cyclone Activity ◽  
Quasi Biennial Oscillation ◽  
Atlantic Basin ◽  
African Rainfall ◽  
Prediction Scheme ◽  
Time Periods

Abstract Predictions of the remainder of the season’s Atlantic basin tropical cyclone activity from 1 August have been issued by Gray and his colleagues at the Tropical Meteorology Project at Colorado State University since 1984. The original 1 August prediction scheme utilized several predictors, including measures of the stratospheric quasi-biennial oscillation (QBO), West African rainfall, El Niño–Southern Oscillation, and the sea level pressure anomaly and upper-tropospheric zonal wind anomalies in the Caribbean basin. The recent failure of the West African rainfall and QBO relationships with Atlantic hurricanes has led to a general degradation of the original 1 August forecast scheme in recent years. It was decided to revise the scheme using only surface data. The development of the National Centers for Environmental Prediction–National Center for Atmospheric Research reanalysis has provided a vast wealth of globally gridded meteorological and oceanic data from 1948 to the present. In addition, other datasets have been extended back even further (to 1900), which allows for a large independent dataset. These longer-period datasets allow for an extended period of testing of the new statistical forecast scheme. A new prediction scheme has been developed on data from 1949 to 1989 and then tested on two independent datasets. One of these datasets is the 16-yr period from 1990 to 2005, and the other dataset is from 1900 to 1948. This allows for an investigation of the statistical significance over various time periods. The statistical scheme shows remarkable stability over an entire century. The combination of these four predictors explains between 45% and 60% of the variance in net tropical cyclone activity over the following separate time periods: 1900–48, 1949–89, 1949–2005, and 1900–2005. The forecast scheme also shows considerable skill as a potential predictor for giving the probabilities of United States landfall. Large differences in U.S. major hurricane landfall are also observed between forecasts that call for active seasons compared with those that call for inactive seasons.

Recent migration of tropical cyclones toward coasts

Science ◽  
2021 ◽  
Vol 371 (6528) ◽  
pp. 514-517 ◽  
Author(s):  
Shuai Wang ◽  
Ralf Toumi
Keyword(s):  
Tropical Cyclone ◽  
Trend Analysis ◽  
Tropical Cyclones ◽  
Tropical Cyclone Activity ◽  
Maximum Intensity ◽  
Coastal Regions ◽  
Cyclone Activity ◽  
Steering Flow ◽  
Annual Frequency ◽  
Tropical Cyclone Tracks

Poleward migrations of tropical cyclones have been observed globally, but their impact on coastal areas remains unclear. We investigated the change in global tropical cyclone activity in coastal regions over the period 1982–2018. We found that the distance of tropical cyclone maximum intensity to land has decreased by about 30 kilometers per decade, and that the annual frequency of global tropical cyclones increases with proximity to land by about two additional cyclones per decade. Trend analysis reveals a robust migration of tropical cyclone activity toward coasts, concurrent with poleward migration of cyclone locations as well as a statistically significant westward shift. This zonal shift of tropical cyclone tracks may be mainly driven by global zonal changes in environmental steering flow.

Passage of Tropical Storm Allison (2001) over southeast Texas recorded in δ18O values of Ostracoda

2008 ◽  
Vol 70 (2) ◽  
pp. 339-342 ◽  
Author(s):  
James R. Lawrence ◽  
Kiseong Hyeong ◽  
Rosalie F. Maddocks ◽  
Kwang-Sik Lee
Keyword(s):  
Tropical Cyclone ◽  
Oxygen Isotope ◽  
Tropical Cyclones ◽  
Tropical Cyclone Activity ◽  
Tropical Storm ◽  
Low Oxygen ◽  
Cyclone Activity ◽  
Southeast Texas

AbstractFreshwater Ostracoda collected in ephemeral pond-waters derived from Tropical Storm Allison (2001, Texas) recorded the unusually low oxygen-isotope values of that storm. Therefore, the potential clearly exists, in locations where tropical cyclones make landfall, to obtain a long-term record of tropical cyclone activity from fossil ostracode calcite.

On the Madden–Julian Oscillation–Atlantic Hurricane Relationship

2010 ◽  
Vol 23 (2) ◽  
pp. 282-293 ◽  
Author(s):  
Philip J. Klotzbach
Keyword(s):  
Tropical Cyclone ◽  
Relative Humidity ◽  
Gulf Of Mexico ◽  
Large Scale ◽  
Tropical Cyclone Activity ◽  
Tropical Atlantic ◽  
Madden Julian Oscillation ◽  
Cyclone Activity ◽  
Short Term ◽  
Potential Predictability

Abstract The large-scale equatorial circulation known as the Madden–Julian oscillation (MJO) has been shown to impact tropical cyclone activity in several basins around the globe. In this paper, the author utilizes an MJO index created by Wheeler and Hendon to examine its impacts on tropical genesis and intensification in the Atlantic. Large differences in frequency and intensity of tropical cyclone activity are seen, both in the tropical Atlantic as well as in the northwest Caribbean and Gulf of Mexico depending on the MJO phase. Coherent changes in upper- and lower-level winds and relative humidity are likely responsible for these differences. Since the MJO shows potential predictability out to about two weeks, the relationships discussed in this paper may be useful for short-term predictions of the probability of tropical cyclone activity in the Atlantic as a complement to the already available longer-term seasonal predictions.

scholarly journals The Impact of the El Niño–Southern Oscillation and Atlantic Meridional Mode on Seasonal Atlantic Tropical Cyclone Activity

2014 ◽  
Vol 27 (14) ◽  
pp. 5311-5328 ◽  
Author(s):  
Christina M. Patricola ◽  
R. Saravanan ◽  
Ping Chang
Keyword(s):  
Tropical Cyclone ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Tropical Cyclone Activity ◽  
Tropical Atlantic ◽  
Cyclone Activity ◽  
The Impact ◽  
Atlantic Meridional Mode ◽  
Atlantic Tropical Cyclone

Abstract Atlantic tropical cyclone (TC) activity is influenced by interannual tropical Pacific sea surface temperature (SST) variability characterized by the El Niño–Southern Oscillation (ENSO), as well as interannual-to-decadal variability in the interhemispheric gradient in tropical Atlantic SST characterized by the Atlantic meridional mode (AMM). Individually, the negative AMM phase (cool northern and warm southern tropical Atlantic SST anomalies) and El Niño each inhibit Atlantic TCs, and vice versa. The impact of concurrent strong phases of the ENSO and AMM on Atlantic TC activity is investigated. The response of the atmospheric environment relevant for TCs is evaluated with a genesis potential index. Composites of observed accumulated cyclone energy (ACE) suggest that ENSO and AMM can amplify or dampen the influence of one another on Atlantic TCs. To support the observational analysis, numerical simulations are performed using a 27-km resolution regional climate model. The control simulation uses observed SST and lateral boundary conditions (LBCs) of 1980–2000, and perturbed experiments are forced with ENSO phases through LBCs and eastern tropical Pacific SST and AMM phases through Atlantic SST. Simultaneous strong El Niño and strongly positive AMM, as well as strong concurrent La Niña and negative AMM, produce near-average Atlantic ACE suggesting compensation between the two influences, consistent with the observational analysis. Strong La Niña and strongly positive AMM together produce extremely intense Atlantic TC activity, supported largely by above average midtropospheric humidity, while strong El Niño and negative AMM together are not necessary conditions for significantly reduced Atlantic tropical cyclone activity.

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