Science.gov

Sample records for idealized tropical cyclone

  1. Tropical-Cyclone Formation: Theory and Idealized Modelling

    DTIC Science & Technology

    2010-11-01

    the forward enstrophy cascade of quasi -two-dimensional turbulence theory in which strong jets and eddies irreversibly deform weaker eddies into...vortex Rossby waves in a three-dimensional quasi - geostrophic model. J. Atmos. Sci., 55, 3176-3207. Montgomery M. T., and R. K. Smith, 2010: Paradigms...1 WMO/CAS/WWW SEVENTH INTERNATIONAL WORKSHOP ON TROPICAL CYCLONES Topic 2.1: Tropical-Cyclone Formation: Theory and Idealized modelling

  2. Multi-model GCM ensemble simulations of idealized tropical cyclones

    NASA Astrophysics Data System (ADS)

    Reed, K. A.; Jablonowski, C.; Ullrich, P. A.; Kent, J.; Lauritzen, P. H.; Taylor, M.; Nair, R.

    2013-12-01

    As General Circulation Models (GCMs) are now capable of running operationally at higher horizontal resolutions than ever before, such models have become a tool of choice for the evaluation of tropical cyclones in current and future climate conditions. GCM horizontal resolutions in the range between 10-50 km are now computationally achievable for seasonal or multi-year simulations and there is growing confidence that high-resolution global models provide reliable representations of many characteristics of tropical storms. However, model design choices are an important source of uncertainty. This is widely documented for physical parameterization suites, but it is less recognized for the dynamical component of models and the physics-dynamics coupling. The study offers a first look into these structural uncertainties. This study focuses on dynamical core model intercomparisons. In particular, it looks at the results of the Dynamical Core Model Intercomparison Project (DCMIP) that took place at the National Center for Atmospheric Research (NCAR) in August 2012. The analysis is focused on the evaluation of an idealized tropical storm and uncertainties triggered by the choice of model dynamical core formulation in various global models. These models include the four dynamical cores available in NCAR's Community Atmosphere Model (Finite-Volume (FV), Spectral-Element (SE) and the Eulerian and semi-Lagrangian spectral transform dynamical cores), the NOAA model FIM, the model ICON (Max-Planck Institute and German Weather Service), GFDL's FV3 model on the cubed-sphere grid, ECMWF's Integrated Forecasting System (IFS) and the model PUMA from the University of Hamburg.

  3. Idealized Study of the Ocean Impact on Coupled Tropical Cyclone Intensity Forecasts

    NASA Astrophysics Data System (ADS)

    Halliwell, G. R.; Gopalakrishnan, S.; Marks, F.

    2013-05-01

    Idealized coupled hurricane forecast experiments are conducted to isolate the impact of the ocean on intensity forecasts. By nesting an initial idealized vortex into a horizontally uniform atmosphere, the influence of large-scale atmospheric processes such as wind shear and dry air entrainment on intensity evolution is minimized, allowing the oceanic influence to dominate. A one-dimensional ocean model is embedded in version 3.2 of the HWRF atmospheric model which is run over a 27-km parent domain with two (9 km and 3km) movable nests. The initial ocean is horizontally uniform, no land is present, and westward storm translation speed is accounted for by bodily advecting the ocean fields to the east. This simple setup forecasts the ocean cold wake with sufficient realism to perform idealized experiments. Experiments are run to determine the impact of available ocean thermal energy (represented by Tropical Cyclone Heat Potential, or TCHP), storm translation speed, and storm size. In all experiments, maximum intensity is reached after ~30 h and displays strong sensitivity to TCHP and comparatively weak sensitivity to translation speed. Small storms are less sensitive to the ocean, particularly for TCHP > 75 kJ/cm2. Analysis of the temporal evolution of enthalpy flux as a function of radius from storm center demonstrates the expected reduction of enthalpy flux associated with the increased SST cooling over low TCHP regions. However, the flux reduction caused by SST cooling alone is reduced by ~40% because of adjustments in T10 and q10, demonstrating the importance of coupled atmosphere-ocean boundary layer processes for understanding the ocean impact on intensity forecasts. Atmospheric boundary layer feedback through changes in T10 and q10 also leads to an asymmetric response between storms that move from regions of high to low and regions of low to high TCHP. The enthalpy flux decrease in the former case exceeds the flux increase in the latter case by roughly a factor

  4. Tropical Cyclone Report, 1993

    DTIC Science & Technology

    1993-01-01

    Office of Naval Research (;rant AN00014-914J1721 STAFF JOINT TYPHOON WARNING CENTER LCDR ANTHONY A. MARTINEZ USN TDO. DEPUTY DIRECTOR LCDR TERESA M...OEJFN TDA. GRAPHICS AGAN ANDRESG.GRANT USN TDA, GRAPHICS UNIVERSITY OF GUAM / JTWC RESEARCH LIAISON DR MARK A. LANDER TROPICAL CYCLONE RESEARCH MR...CHARLES P. GUARD TROPICAL CYCLONE RESEARCH * TRANSFERRED DURING 1993 ** ACTIVE DUTY TRAINING S~ii FOREWORD The Annual Tropical Cyclone Report is past four

  5. Tropical cyclone formation

    SciTech Connect

    Montgomery, M.T.; Farrell, B.F. )

    1993-01-15

    The physics of tropical cyclone formation is not well understood, and more is known about the mature hurricane than the formative mechanisms that produce it. It is believed part of the reason for this can be traced to insufficient upper-level atmospheric data. Recent observations suggest that tropical cyclones are initiated by asymmetric interactions associated with migratory upper-level potential vorticity disturbances and low-level disturbances. Favored theories of cyclones formation, however, focus on internal processes associated with cumulus convection and/or air-sea interaction. This work focuses on external mechanisms of cyclone formation and, using both a two- and three-dimensional moist geostrophic momentum model, investigates the role of upper-level potential vorticity disturbances on the formation process. A conceptual model of tropical cyclone formation is proposed, and implications of the theory are discussed. 71 refs., 5 figs., 1 tab.

  6. Tropical Cyclone Nargis: 2008

    NASA Image and Video Library

    This new animation, developed with the help of NASA's Pleiades supercomputer, illustrates how tropical cyclone Nargis formed in the Indian Ocean's Bay of Bengal over several days in late April 2008...

  7. Grey swan tropical cyclones

    NASA Astrophysics Data System (ADS)

    Lin, Ning; Emanuel, Kerry

    2016-01-01

    We define `grey swan’ tropical cyclones as high-impact storms that would not be predicted based on history but may be foreseeable using physical knowledge together with historical data. Here we apply a climatological-hydrodynamic method to estimate grey swan tropical cyclone storm surge threat for three highly vulnerable coastal regions. We identify a potentially large risk in the Persian Gulf, where tropical cyclones have never been recorded, and larger-than-expected threats in Cairns, Australia, and Tampa, Florida. Grey swan tropical cyclones striking Tampa, Cairns and Dubai can generate storm surges of about 6 m, 5.7 m and 4 m, respectively, with estimated annual exceedance probabilities of about 1/10,000. With climate change, these probabilities can increase significantly over the twenty-first century (to 1/3,100-1/1,100 in the middle and 1/2,500-1/700 towards the end of the century for Tampa). Worse grey swan tropical cyclones, inducing surges exceeding 11 m in Tampa and 7 m in Dubai, are also revealed with non-negligible probabilities, especially towards the end of the century.

  8. Idealized Numerical Modeling Experiments of the Diurnal Cycle of Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Navarro, Erika L.

    Numerical experiments are performed to evaluate the role of the daily cycle of radiation on axisymmetric hurricane structure. Although a diurnal response in the high cloudiness of tropical cyclones (TCs) has been well documented in the past, the impact to storm structure and intensity remains unknown. Previous modeling work attributes differences in results to experimental setup (e.g., initial and boundary conditions) as well as to radiative parameterization schemes. Here, a numerically-simulated TC in a statistical steady-state is examined to quantify the TC response to the daily cycle of radiation, and a modified, Sawyer-Eliassen approach is applied to evaluate the dynamical mechanism. Fourier analysis in time reveals a spatially coherent pattern in the temperature, wind, and latent heating tendency fields that is statistically significant at the 95% level. This signal accounts for up to 62% of the variance in the temperature field of the upper troposphere, and is mainly concentrated in the TC outflow layer. Composite analysis reveals a cycle in the storm intensity in the low-levels, which lags a periodic response in the latent heating tendency by 6 h. Average magnitudes of the azimuthal wind anomalies near the radius of maximum wind (RMW) are 1 m/s and account for 21% of the overall variance. A hypothesis is drawn from these results that the TC diurnal cycle is comprised of two distinct, periodic circulations: (1) a radiatively-driven circulation in the TC outflow layer due to absorption of solar radiation, and (2) a convectively-driven circulation in the lower and middle troposphere due to anomalous latent heating from convection. These responses are coupled and are periodic with respect to the diurnal cycle. Using a modified, Sawyer-Eliassen approach for time-varying heating, these hypotheses are evaluated to determine the impact of periodic diurnal heating on a balanced vortex. Periodic heating near the top of the vortex produces a local overturning

  9. 1983 Annual Tropical Cyclone Report

    DTIC Science & Technology

    1983-01-01

    influence tropical cyclone intensity. All charts are hand-plotted over areas of tropical cyclone activity to provide all available data as soon as... influenced by the maturity and vertical extent of the tropical cyclone. For mature tropical cyclones located south of the subtropical ridge, forecast changes...pattern. An essential element affecting each intensity forecast is the accompanying forecast track and the influence of environmental parameters along

  10. Evaluation of the Utility of Static and Adaptive Mesh Refinement for Idealized Tropical Cyclone Problems in a Spectral Element Shallow Water Model

    DTIC Science & Technology

    2015-04-09

    Laboratory,Marine Meteorology Division,Monterey,CA,93943 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND...adaptive mesh refinement1 for idealized tropical cyclone problems in a spectral element2 shallow water model3 Eric A. Hendricks ∗ Marine Meteorology Division...CA, USA Melinda S. Peng, James D. Doyle, and Qingfang Jiang Marine Meteorology Division, Naval Research Laboratory, Monterey, CA, USA Mon. Wea. Rev

  11. Assessing Tropical Cyclone Damage

    NASA Astrophysics Data System (ADS)

    Done, J.; Czajkowski, J.

    2012-12-01

    Landfalling tropical cyclones impact large coastal and inland areas causing direct damage due to winds, storm-surge flooding, tornadoes, and precipitation; as well as causing substantial indirect damage such as electrical outages and business interruption. The likely climate change impact of increased tropical cyclone intensity, combined with increases in exposure, bring the possibility of increased damage in the future. A considerable amount of research has focused on modeling economic damage due to tropical cyclones, and a series of indices have been developed to assess damages under climate change. We highlight a number of ways this research can be improved through a series of case study analyses. First, historical loss estimates are revisited to properly account for; time, impacted regions, the source of damage by type, and whether the damage was direct/indirect and insured/uninsured. Second, the drivers of loss from both the socio-economic and physical side are examined. A case is made to move beyond the use of maximum wind speed to more stable metrics and the use of other characteristics of the wind field such as direction, degree of gustiness, and duration is explored. A novel approach presented here is the potential to model losses directly as a function of climate variables such as sea surface temperature, greenhouse gases, and aerosols. This work is the first stage in the development of a tropical cyclone loss model to enable projections of losses under scenarios of both socio-economic change (such as population migration or altered policy) and physical change (such as shifts in tropical cyclone activity one from basin to another or within the same basin).

  12. Tropical Cyclone Gonu

    NASA Technical Reports Server (NTRS)

    2007-01-01

    You might expect to see a storm with near-perfect symmetry and a well-defined eye hovering over the warm waters of the Caribbean or in the South Pacific, but Tropical Cyclone Gonu showed up in an unusual place. On June 4, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this image, Tropical Cyclone Gonu was approaching the northeastern shore of Oman, a region better known for hot desert conditions. Though rare, cyclones like Gonu are not unheard of in the northern Indian Ocean basin. Most cyclones that form in the region form over the Bay of Bengal, east of India. Those that take shape over the Arabian Sea, west of the Indian peninsula, tend to be small and fizzle out before coming ashore. Cyclone Gonu is a rare exception. As of June 4, 2007, the powerful storm had reached a dangerous Category Four status, and it was forecast to graze Oman's northeastern shore, following the Gulf of Oman. According to storm statistics maintained on Unisys Weather, the last storm of this size to form over the Arabian Sea was Cyclone 01A, which tracked northwest along the coast of India between May 21 and May 28, 2001. Unlike Gonu's forecasted track, Cyclone 01A never came ashore. MODIS acquired this photo-like image at 12:00 p.m. local time (9:00 UTC), a few hours after the Joint Typhoon Warning Center estimated Gonu's sustained winds to be over 240 kilometers per hour (145 miles per hour). The satellite image confirms that Gonu was a super-powerful cyclone. The storm has the hallmark tightly wound arms that spiral around a well-defined, circular eye. The eye is surrounded by a clear wall of towering clouds that cast shadows on the surrounding clouds. Called hot towers, these clouds are a sign of the powerful uplift that feeds the storm. The symmetrical spirals, clear eye, and towering clouds are all features regularly seen in satellite images of other particularly powerful cyclones, which are also known as typhoons or hurricanes

  13. Tropical Cyclone Gonu

    NASA Technical Reports Server (NTRS)

    2007-01-01

    You might expect to see a storm with near-perfect symmetry and a well-defined eye hovering over the warm waters of the Caribbean or in the South Pacific, but Tropical Cyclone Gonu showed up in an unusual place. On June 4, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this image, Tropical Cyclone Gonu was approaching the northeastern shore of Oman, a region better known for hot desert conditions. Though rare, cyclones like Gonu are not unheard of in the northern Indian Ocean basin. Most cyclones that form in the region form over the Bay of Bengal, east of India. Those that take shape over the Arabian Sea, west of the Indian peninsula, tend to be small and fizzle out before coming ashore. Cyclone Gonu is a rare exception. As of June 4, 2007, the powerful storm had reached a dangerous Category Four status, and it was forecast to graze Oman's northeastern shore, following the Gulf of Oman. According to storm statistics maintained on Unisys Weather, the last storm of this size to form over the Arabian Sea was Cyclone 01A, which tracked northwest along the coast of India between May 21 and May 28, 2001. Unlike Gonu's forecasted track, Cyclone 01A never came ashore. MODIS acquired this photo-like image at 12:00 p.m. local time (9:00 UTC), a few hours after the Joint Typhoon Warning Center estimated Gonu's sustained winds to be over 240 kilometers per hour (145 miles per hour). The satellite image confirms that Gonu was a super-powerful cyclone. The storm has the hallmark tightly wound arms that spiral around a well-defined, circular eye. The eye is surrounded by a clear wall of towering clouds that cast shadows on the surrounding clouds. Called hot towers, these clouds are a sign of the powerful uplift that feeds the storm. The symmetrical spirals, clear eye, and towering clouds are all features regularly seen in satellite images of other particularly powerful cyclones, which are also known as typhoons or hurricanes

  14. 1989 Annual Tropical Cyclone Report

    DTIC Science & Technology

    1995-01-01

    z TYPHOON GAY (32W) The fust tropical cyclone of November turned out to be the worst tropical cyclone to affect the Malay Peninsula in 35 years... Gay developed in the Gulf of Thailand, crossed the Malay Peninsula into the Bay of Bengal and slammed into India with peak sustained winds of 140 kt...70 rn/see). Unique because of its small size, intensity, and point of origin, Gay challenged forecasters by crossing two different tropical cyclone

  15. Mesoscale Processes in Tropical Cyclones

    DTIC Science & Technology

    2016-06-07

    develop improved understanding and prediction of the atmosphere, with particular emphasis on tropical cyclones. Our work encompasses research into basic...subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE...and development; an analysis of the predictability of tropical cyclone tracks; the Global Guide to Tropical Cyclone Forecasting; and several

  16. Effect of Land and its Surface Characteristics on Tropical Cyclone Intensity and Structure - An idealized study using HWRF

    NASA Astrophysics Data System (ADS)

    Subramanian, S.; Gopalakrishnan, S. G.; Niyogi, D.; Marks, F., Jr.

    2012-12-01

    Although the upward transfer of enthalpy fluxes from the ocean surface to the atmosphere and the downward transfer of momentum from the atmosphere to ocean surface eventually controls the evolution and intensification of a Tropical Cyclone (TC) (Ooyama 1969; Anthes and Chang 1978; Tuleya and Kurihara 1978; Emanuel 1995), several TCs are known to sustain over land and some of them have even been found to intensify over land. Past studies have emphasized on the importance of land surface affecting storm development and have showed that anomalously wet conditions may sustain or strengthen the storm if the surface temperature is sufficiently high (Emanuel, 1995; Emanuel et al., 2004, 2008; Kellner et al., 2012; Tuleya, 1994). We explore the fundamental interactions between land surface and TC and aim to understand the mechanisms involved in the sustenance or strengthening of such hurricanes. This study uses the idealized framework of the operationally adopted Hurricane Weather Research and Forecasting system (HWRF) with similar setting as that of Gopalakrishnan et al., 2011, 2012. The TC simulated over an all ocean domain was designated as the control experiment. To simulate landfall and to study the land surface effects on TCs, land was included in the western half of the domain using various land use and soil categories from the USGS table. The results from various experiments were compared and the storm's development, secondary circulation involved in the storm, the role friction plays in the cyclone processes etc were studied with special focus on the land surface effects on TC. The TC development in the experiments with land mass was not as intense as in the control and the time evolution of storms for major cases is given in Figure 1. Montgomery et al., 2010 have explained the importance of surface drag on primary and secondary circulations in TCs over ocean. Results from this study also indicate stronger inflow makes for stronger storm as in Gopalakrishnan et al

  17. Atlantic tropical cyclones revisited

    NASA Astrophysics Data System (ADS)

    Mann, Michael E.; Emanuel, Kerry A.; Holland, Greg J.; Webster, Peter J.

    Vigorous discussions have taken place recently in Eos [e.g., Mann and Emanuel, 2006; Landsea, 2007] and elsewhere [Emanuel, 2005; Webster et al., 2005; Hoyos et al., 2006; Trenberth and Shea, 2006; Kossin et al., 2007] regarding trends in North Atlantic tropical cyclone (TC) activity and their potential connection with anthropogenic climate change. In one study, for example [Landsea, 2007], it is argued that a substantial underestimate of Atlantic tropical cyclone counts in earlier decades arising from insufficient observing systems invalidates the conclusion that trends in TC behavior may be connected to climate change. Here we argue that such connections are in fact robust with respect to uncertainties in earlier observations.Several recent studies have investigated trends in various measures of TC activity. Emanuel [2005] showed that a measure of total power dissipation by TCs (the power dissipation index, or PDI) is highly correlated with August-October sea surface temperatures (SST) over the main development region (MDR) for Atlantic TCs over at least the past half century. Some support for this conclusion was provided by Sriver and Ruber [2006]. Webster et al. [2005] demonstrated a statistically significant increase in recent decades in both the total number of the strongest category cyclones (categories 4 and 5) and the proportion of storms reaching hurricane intensity. Hoyos et al. [2006] showed that these increases were closely tied to warming trends in tropical Atlantic SST, while, for example, the modest decrease in vertical wind shear played a more secondary role. Kossin et al. [2007] called into question some trends in other basins, based on a reanalysis of past TC data, but they found the North Atlantic trends to be robust.

  18. Paradigms for Tropical Cyclone Intensification

    DTIC Science & Technology

    2014-03-01

    structure of the initial vortex is completely dwarfed by the local vorticity of the VHTs. Comparing Fig. 8 with Fig. 9 shows that the VHTs move...Tropical cyclones. Annu. Rev. Earth Planet . Sci., 31, 75–104. Emanuel K.A. 2004. Tropical cyclone energetics and structure, Atmo- spheric

  19. Tropical Cyclone Indlala

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On March 14, 2007, storm-weary Madagascar braced for its fourth land-falling tropical cyclone in as many months. Cyclone Indlala was hovering off the island's northeast coast when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this photo-like image at 1:40 p.m. local time (10:40 UTC). Just over a hundred kilometers offshore, the partially cloudy eye at the heart of the storm seems like a vast drain sucking in a disk of swirling clouds. According to reports from the Joint Typhoon Warning Center issued less than three hours after MODIS captured this image, Indlala had winds of 115 knots (132 miles per hour), with gusts up to 140 knots (161 mph). Wave heights were estimated to be 36 feet. At the time of the report, the storm was predicted to intensify through the subsequent 12-hour period, to turn slightly southwest, and to strike eastern Madagascar as a Category 4 storm with sustained winds up to 125 knots (144 mph), and gusts up to 150 knots (173 mph). According to Reuters AlertNet news service, Madagascar's emergency response resources were taxed to their limit in early March 2007 as a result of extensive flooding in the North, drought and food shortages in the South, and three previous hits from cyclones in the preceding few months: Bondo in December 2006, Clovis in January 2007, and Gamede in February.

  20. Tropical Cyclone Indlala

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On March 14, 2007, storm-weary Madagascar braced for its fourth land-falling tropical cyclone in as many months. Cyclone Indlala was hovering off the island's northeast coast when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this photo-like image at 1:40 p.m. local time (10:40 UTC). Just over a hundred kilometers offshore, the partially cloudy eye at the heart of the storm seems like a vast drain sucking in a disk of swirling clouds. According to reports from the Joint Typhoon Warning Center issued less than three hours after MODIS captured this image, Indlala had winds of 115 knots (132 miles per hour), with gusts up to 140 knots (161 mph). Wave heights were estimated to be 36 feet. At the time of the report, the storm was predicted to intensify through the subsequent 12-hour period, to turn slightly southwest, and to strike eastern Madagascar as a Category 4 storm with sustained winds up to 125 knots (144 mph), and gusts up to 150 knots (173 mph). According to Reuters AlertNet news service, Madagascar's emergency response resources were taxed to their limit in early March 2007 as a result of extensive flooding in the North, drought and food shortages in the South, and three previous hits from cyclones in the preceding few months: Bondo in December 2006, Clovis in January 2007, and Gamede in February.

  1. Tropical Cyclone Information System

    NASA Technical Reports Server (NTRS)

    Li, P. Peggy; Knosp, Brian W.; Vu, Quoc A.; Yi, Chao; Hristova-Veleva, Svetla M.

    2009-01-01

    The JPL Tropical Cyclone Infor ma tion System (TCIS) is a Web portal (http://tropicalcyclone.jpl.nasa.gov) that provides researchers with an extensive set of observed hurricane parameters together with large-scale and convection resolving model outputs. It provides a comprehensive set of high-resolution satellite (see figure), airborne, and in-situ observations in both image and data formats. Large-scale datasets depict the surrounding environmental parameters such as SST (Sea Surface Temperature) and aerosol loading. Model outputs and analysis tools are provided to evaluate model performance and compare observations from different platforms. The system pertains to the thermodynamic and microphysical structure of the storm, the air-sea interaction processes, and the larger-scale environment as depicted by ocean heat content and the aerosol loading of the environment. Currently, the TCIS is populated with satellite observations of all tropical cyclones observed globally during 2005. There is a plan to extend the database both forward in time till present as well as backward to 1998. The portal is powered by a MySQL database and an Apache/Tomcat Web server on a Linux system. The interactive graphic user interface is provided by Google Map.

  2. The Dynamics of Tropical Cyclones

    DTIC Science & Technology

    2016-06-07

    The Dynamics of Tropical Cyclones Roger K. Smith Meteorological Institute University of Munich Theresienstr. 37, 80333 Munich, Germany phone +49 (89...University of Munich, Meteorological Institute,Theresienstr. 37,80333 Munich, Germany, 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING...tropical cyclones’ which was held in Kaufbeuren, Germany from 10-14 May 1999 and was sponsored by ONR and the WMO Tropical Meteorology Research

  3. Post-Tropical Cyclone Matthew

    NASA Image and Video Library

    2017-09-28

    NASA Gets a Last Look at Post-Tropical Cyclone Matthew Before It was Swallowed Up Post-Tropical Cyclone Matthew was swallowed up or absorbed by a cold front on Oct. 10, but NASA's Terra satellite captured a last look at the storm before that happened. On Sunday, Oct. 9, 2016 at 11:45 a.m. EDT (1545 UTC) NASA's Terra satellite captured a last look at Post-Tropical Cyclone Matthew as it was being absorbed by a cold front along the U.S. Eastern Seaboard. Read more: go.nasa.gov/2dfhQg9 Credits: NASA Goddard MODIS Rapid Response Team

  4. 1992 Annual Tropical Cyclone Report

    DTIC Science & Technology

    1992-01-01

    Esau Farida Ian Gerda Fran Gene Hett ie Neville Jane/Irna Innis Totsls: Percentage of Total: 17 32 95 25 110 85 0 0 35 21 120 36 3 0 12 45 70 19 6 137...those for Tropical Cyclone 18P were preced- ed by Tropical Cyclone Formation Alerts. Tropical cyclones 06P (Val), 21P ( Esau ), and 25P (Fran) all made it...Cliff 15S Celesta 16s ____ 17P Daman 18P ---- 19S Davilia 20S Harriet 21P Esau 22S Farida 23s Ian 24S Gerda 25P Fran* 26P Gene 27P Hettie 28s Neville

  5. Cloudsat tropical cyclone database

    NASA Astrophysics Data System (ADS)

    Tourville, Natalie D.

    CloudSat (CS), the first 94 GHz spaceborne cloud profiling radar (CPR), launched in 2006 to study the vertical distribution of clouds. Not only are CS observations revealing inner vertical cloud details of water and ice globally but CS overpasses of tropical cyclones (TC's) are providing a new and exciting opportunity to study the vertical structure of these storm systems. CS TC observations are providing first time vertical views of TC's and demonstrate a unique way to observe TC structure remotely from space. Since December 2009, CS has intersected every globally named TC (within 1000 km of storm center) for a total of 5,278 unique overpasses of tropical systems (disturbance, tropical depression, tropical storm and hurricane/typhoon/cyclone (HTC)). In conjunction with the Naval Research Laboratory (NRL), each CS TC overpass is processed into a data file containing observational data from the afternoon constellation of satellites (A-TRAIN), Navy's Operational Global Atmospheric Prediction System Model (NOGAPS), European Center for Medium range Weather Forecasting (ECMWF) model and best track storm data. This study will describe the components and statistics of the CS TC database, present case studies of CS TC overpasses with complementary A-TRAIN observations and compare average reflectivity stratifications of TC's across different atmospheric regimes (wind shear, SST, latitude, maximum wind speed and basin). Average reflectivity stratifications reveal that characteristics in each basin vary from year to year and are dependent upon eye overpasses of HTC strength storms and ENSO phase. West Pacific (WPAC) basin storms are generally larger in size (horizontally and vertically) and have greater values of reflectivity at a predefined height than all other basins. Storm structure at higher latitudes expands horizontally. Higher vertical wind shear (≥ 9.5 m/s) reduces cloud top height (CTH) and the intensity of precipitation cores, especially in HTC strength storms

  6. Black Swan Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Emanuel, K.; Lin, N.

    2012-12-01

    Virtually all assessments of tropical cyclone risk are based on historical records, which are limited to a few hundred years at most. Yet stronger TCs may occur in the future and at places that have not been affected historically. Such events lie outside the realm of historically based expectations and may have extreme impacts. Their occurrences are also often made explainable after the fact (e.g., Hurricane Katrina). We nickname such potential future TCs, characterized by rarity, extreme impact, and retrospective predictability, "black swans" (Nassim Nicholas Taleb, 2007). As, by definition, black swan TCs have yet to happen, statistical methods that solely rely on historical track data cannot predict their occurrence. Global climate models lack the capability to predict intense storms, even with a resolution as high as 14 km (Emanuel et al. 2010). Also, most dynamic downscaling methods (e.g., Bender et al. 2010) are still limited in horizontal resolution and are too expensive to implement to generate enough events to include rare ones. In this study, we apply a simpler statistical/deterministic hurricane model (Emanuel et al. 2006) to simulate large numbers of synthetic storms under a given (observed or projected) climate condition. The method has been shown to generate realistic extremes in various basins (Emanuel et al. 2008 and 2010). We also apply a hydrodynamic model (ADCIRC; Luettich et al. 1992) to simulate the storm surges generated by these storms. We then search for black swan TCs, in terms of the joint wind and surge damage potential, in the generated large databases. Heavy rainfall is another important TC hazard and will be considered in a future study. We focus on three areas: Tampa Bay in the U.S., the Persian Gulf, and Darwin in Australia. Tampa Bay is highly vulnerable to storm surge as it is surrounded by shallow water and low-lying lands, much of which may be inundated by a storm tide of 6 m. High surges are generated by storms with a broad

  7. An Observational Analysis of Tropical Cyclone Recurvature.

    DTIC Science & Technology

    1991-05-01

    SR = Slowly recurving cyclones TC = Tropical Cyclone TUTT = Tropical Upper Tropospheric Trough W = West WNW = West-Northwest v Chapter 1 INTRODUCTION...latitude at which the cyclone was located. Observations also showed that not all troughs approaching a cyclone caused recurvature. Mid- latitude troughs ...general synoptic conditions which were favorable for tropical cyclone recurvature. These included: 1. High amplitude troughs extending from the westerlies

  8. Annual Tropical Cyclone Report 2010

    DTIC Science & Technology

    2010-01-01

    period of rapid intensification. Tropical Cyclone 04B matured as a relatively small cyclone, its upper-level cirrus cloud shield spanning... defined cirrus outflow streak poleward of the low-level circulation center around 22/00Z. These structural changes are evident in the satellite imagery...erratically based on the upper level cloud patterns and convective maxima. It was not until visible imagery became available, that the two low level

  9. APR-2 Tropical Cyclone Observations

    NASA Technical Reports Server (NTRS)

    Durden, S. L.; Tanelli, S.

    2011-01-01

    The Second Generation Airborne Precipitation Radar (APR-2) participated in the Genesis and Rapid Intensification Processes (GRIP) experiment in August and September of 2010, collecting a large volume of data in several tropical systems, including Hurricanes Earl and Karl. Additional measurements of tropical cyclone have been made by APR-2 in experiments prior to GRIP (namely, CAMEX-4, NAMMA, TC4); Table 1 lists all the APR-2 tropical cyclone observations. The APR-2 observations consist of the vertical structure of rain reflectivity at 13.4 and 35.6 GHz, and at both co-polarization and crosspolarization, as well as vertical Doppler measurements and crosswind measurements. APR-2 normally flies on the NASA DC-8 aircraft, as in GRIP, collecting data with a downward looking, cross-track scanning geometry. The scan limits are 25 degrees on either side of the aircraft, resulting in a roughly 10-km swath, depending on the aircraft altitude. Details of the APR-2 observation geometry and performance can be found in Sadowy et al. (2003).The multiparameter nature of the APR-2 measurements makes the collection of tropical cyclone measurements valuable for detailed studies of the processes, microphysics and dynamics of tropical cyclones, as well as weaker systems that are associated with tropical cyclone formation. In this paper, we give a brief overview of how the APR-2 data are processed. We also discuss use of the APR-2 cross-track winds to estimate various quantities of interest in in studies of storm intensification. Finally, we show examples of the standard products and derived information.

  10. APR-2 Tropical Cyclone Observations

    NASA Technical Reports Server (NTRS)

    Durden, S. L.; Tanelli, S.

    2011-01-01

    The Second Generation Airborne Precipitation Radar (APR-2) participated in the Genesis and Rapid Intensification Processes (GRIP) experiment in August and September of 2010, collecting a large volume of data in several tropical systems, including Hurricanes Earl and Karl. Additional measurements of tropical cyclone have been made by APR-2 in experiments prior to GRIP (namely, CAMEX-4, NAMMA, TC4); Table 1 lists all the APR-2 tropical cyclone observations. The APR-2 observations consist of the vertical structure of rain reflectivity at 13.4 and 35.6 GHz, and at both co-polarization and crosspolarization, as well as vertical Doppler measurements and crosswind measurements. APR-2 normally flies on the NASA DC-8 aircraft, as in GRIP, collecting data with a downward looking, cross-track scanning geometry. The scan limits are 25 degrees on either side of the aircraft, resulting in a roughly 10-km swath, depending on the aircraft altitude. Details of the APR-2 observation geometry and performance can be found in Sadowy et al. (2003).The multiparameter nature of the APR-2 measurements makes the collection of tropical cyclone measurements valuable for detailed studies of the processes, microphysics and dynamics of tropical cyclones, as well as weaker systems that are associated with tropical cyclone formation. In this paper, we give a brief overview of how the APR-2 data are processed. We also discuss use of the APR-2 cross-track winds to estimate various quantities of interest in in studies of storm intensification. Finally, we show examples of the standard products and derived information.

  11. Tropical Cyclone Ensemble Data Assimilation

    DTIC Science & Technology

    2012-09-30

    described above, but using a vertical window of influence of 2.0 times the scale hight . Notice that meaningful vertical correlation is found by LETKF...between the scatterometer observation and many points throughout the troposphere. This suggests that for assimilation near tropical cyclones that have

  12. Structure of Developing Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Molinari, J. E.

    2006-12-01

    Considerable progress has been made in the numerical modeling of tropical cyclones. The very high resolution now routinely used in research models allows realistic simulation of eyewall structure and breakdown, vortex Rossby waves, and numerous other processes that were beyond the capability of previous generations of models. At least one aspect of tropical cyclones, however, has not been reproduced in the current generation of models: early development (or lack of development) during tropical depression and early tropical storm stages. During such times, vertical wind shear often plays a critical role. In this presentation, details of the structure of four tropical cyclones at early stages will be given: Claudette (2003), Danny (1997), Gabrielle (2001), and Edouard (2002). The first three contained intense vortices that formed within downshear convection. Deep-layer vertical wind shear ranged from 8-15 m/s in the storms. In Claudette, a hurricane formed that lasted only 6 hours. In Danny and Gabrielle, the downshear vortices became the new storm center. One became a hurricane and one did not. In Edouard, vertical shear was even larger. Convection fluctuated between downshear of the center and over the center, with analogous intensity changes. This behavior is known to forecasters, but the causes of such fluctuations remain uncertain. The evolving structure of these four storms will be shown, with emphasis on the variation of convection, equivalent potential temperature in the lower troposphere, and azimuthal asymmetries of wind and circulation. Contrast will be made between the structure of forming tropical cyclones in nature and those seen in mesoscale numerical models. Some remarks will be given on the key physical processes that must be simulated.

  13. Where will tropical cyclogenesis occur around a preexisting tropical cyclone?

    NASA Astrophysics Data System (ADS)

    Shi, Wenli; Fei, Jianfang; Huang, Xiaogang; Ma, Zhanhong

    2017-01-01

    An observational study focusing on the locations of tropical cyclogenesis induced by tropical cyclone energy dispersion (TCED) in the western North Pacific is conducted. Statistical results indicate that the cyclogenesis cases associated with TCED widely occur around preexisting tropical cyclones (TCs). In addition to the typical scenario of cyclogenesis to the southeast of a preexisting TC, new TCs can even form in the east or southwest directions at distances ranging from 1000 km to 3500 km. Further analyses reveal that the locations of cyclogenesis are mainly governed by large-scale environments via regulating the patterns of Rossby wave trains. The observational relationships between wave train regimes and the structures of environmental flows are revealed, which are broadly consistent with previous idealized numerical simulations. The results in this study provide a valuable reference for the prediction of cyclogenesis considering the TCED mechanism.

  14. Idealized simulations of sting jet cyclones

    NASA Astrophysics Data System (ADS)

    Baker, L. H.; Gray, S. L.; Clark, P. A.

    2012-04-01

    An idealized modeling study of sting-jet cyclones is presented. Sting jets are descending mesoscale jets that occur in some extratropical cyclones and produce localized regions of strong low-level winds in the frontal fracture region. Moist baroclinic lifecycle (LC1) simulations are performed with modifications to produce cyclones resembling observed sting-jet cyclones. Two jets exist in the control idealized cyclone that descend into the frontal fracture region and result in strong winds near to the top of the boundary layer; one of these satisfies the criteria for a sting jet, the other is associated with the warm front. Sensitivity experiments show that both these jets are robust features. The sting jet strength (measured by maximum low-level wind speed or descent rate) increases with the cyclone growth rate; growth rate increases with increasing basic-state zonal jet maximum or decreasing basic-state tropospheric static stability. The two cyclones with the weakest basic-state static stability have by far the strongest sting jets, with descent rates comparable to those observed. Evaporative cooling contributes up to 20% of the descent rate in these sting jets compared with up to 4% in the other sting jets. Conditional symmetric instability (CSI) release in the cloud head also contributes to the sting jet, although there is less extensive CSI than in observed cases. The robustness of the sting jets suggests that they could occur frequently in cyclones with frontal fracture; however, they are unlikely to be identified unless momentum transport through the boundary layer leads to strong surface wind gusts.

  15. Fluid Mechanics of Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Lighthill, James, Sir

    Typhoons in the northwest Pacific and hurricanes in the northeast Atlantic are particular instances of a global phenomenon with frequently disastrous consequences known as the Tropical Cyclone (TC). This is an intense cyclone, generated over a tropical ocean with kinetic energy 1018 J or more, which extends over several hundred kilometres and yet is above all characterized by its calm central region: ``the eye of the storm''. In a TC (not, of course, to be confused with such completely different phenomena as tornadoes) both the energy input and its dissipation mainly occur within that boundary layer between air and ocean which, at high TC wind speeds of 50-60 m/s, comprises essentially ``a third fluid'': ocean spray. Afterwards, as a TC reaches land, disastrous effects of several different kinds may occur, and this paper outlines how fluid mechanics contributes towards worldwide struggles to reduce the human impact of TC disasters.

  16. 1998 Annual Tropical Cyclone Report

    DTIC Science & Technology

    1998-01-01

    1998 ANNUAL TROPICAL CYCLONE REPORT Microwave imagery of Typhoon Rex (06W) as it passed through the Bonin Islands, taken at 0800Z on 28 August...System intensity was estimated at 115 KTS. JOINT TYPHOON WARNING CENTER PEARL HARBOR, HAWAII REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188...Stapler, Wendell ; 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME AND ADDRESS Joint Typhoon Warning Center 425

  17. Annual Tropical Cyclone Report, 1983.

    DTIC Science & Technology

    1983-01-01

    used. patterns, mid-latitude steering currents, and The warning position is then obtained by features that may influence tropical cyclone determining the...description of these techniques (2) Determination of the best steering is presented in Chapter IV): level is partly influenced by the maturity and vertical...valid. accompanying forecast track and the influence This plain language message is intended of environmental parameters along that track, to provide

  18. 1990 Annual Tropical Cyclone Report

    DTIC Science & Technology

    1995-01-01

    western Pacific Ocean. Its built-in sectorizer allows scale expansion and downloading of electronic files to evaluate the 4 data effectively, and...direction, speed of movement and the influence of the different scales of motions. If the fix data are not available due to reconnaissance platform...into a tropical cyclone as the low-level circulation center moved beneath an area of upper-level divergence. The synoptic scale upper-level anticyclone

  19. Tropical Cyclone Structure and Motion

    DTIC Science & Technology

    2016-06-07

    and P. A. Harr N0001499WR30003 LONG-TERM GOALS To improve tropical cyclone track and intensity prediction through a research program combining high...period. In cases where forecast models did poorly in predicting the motion and re-intensification of the storm during these transitional periods...to the complexity of the modeling system, isolating each physical process in turn. The U.S. Navy’s coupled ocean-atmosphere mesoscale prediction

  20. 1994 Annual Tropical Cyclone Report

    DTIC Science & Technology

    1995-01-01

    08 E), was unusual in that it traversed the areas of responsibility of all three US tropical cyclone warning centers — the National Hurricane Center...NHC), the Central Pacific Hurricane Center (CPHC), and the Joint Typhoon Warning Center (JTWC). During its 18-day life, it traveled over 3600 nm (6670...CPHC to Hurricane Li. Peak intensity was 65 kt (33 m/s). The CPHC issued its final warning on Hurricane Li at 12 1800Z as it crossed the

  1. 1997 Annual Tropical Cyclone Report

    DTIC Science & Technology

    1997-01-01

    WARNING CENTER LCOL MARK ANDREWS USAF DIRECTOR * LCDR ERIC J. TREHUBENKO USN TDO, DEPUTY DIRECTOR LCDR KENNETH A. MALMQUIST USN TDO...signature characteristics of the distribution, character and behavior of the tropical cyclones (TCs) of the WNP during 1997 (some known to be related to...possessing an extreme intensity of 160 kt (82 m/sec). Some of these unusual characteristics of the distribution and behavior of the TCs in the western North

  2. Tropical Cyclone Report, 1986.

    DTIC Science & Technology

    1986-01-01

    4- A, TOKYrO 44 % CHIC ., FigHr 3J74IPoMfATM gudne hog 72hor fo eac twlehu ero.Nt h (114 kin )* eas of Hog Kn t U20 ih a - 6 & intesit of5 6k 28 m...Carmen (15W) passed just 50 nm (93 kin ) north of the island of Guam. At picture time, 042355Z October 1986, the aircraft reconnaissance mission (AF966...the subtropical passed 15 nm (28 kin ) north of the island of Salpan in ridge. Typhoon Carmen (15W) was the third tropical the Marianas at near super

  3. Predictability of Sheared Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Tao, D.

    2015-12-01

    Predictability of the formation, rapid intensification and eyewall replacement of sheared tropical cyclones (TCs) are explored through a series of convection-permitting ensemble simulations using the Weather Research and Forecasting (WRF) model with different environmental vertical wind shear, sea-surface temperature (SST), and ambient moisture conditions. It is found that the intrinsic predictability of the RI onset time is more limited with increasing shear magnitude until the shear magnitude is large enough to prevent the TC formation. Based on ensemble sensitivity and correlation analysis, the RI onset timing within one set is largely related to the vortex tilt magnitude, the diabatic heating distribution and the strength of the primary vortex circulation. Systematic differences amongst the ensemble members begin to arise right after the initial burst of moist convection associated with the incipient vortex. This difference from the randomness inherent in moist convection in terms of both location and intensity first changes the TC vortex structure subtly and then leads to the deviations in system scales and eventually in the development (and precession) of the TC. On average, a higher SST has a positive effect on the TC formation and reduces the uncertainty of development under all shear conditions, while a drier environment has a negative impact on the TCs development and either broadens the ensemble spread of RI onset time or prevents the storm from forming when the shear-induced tilt is large. Nevertheless, the uncertainty in environmental shear magnitudes may dominate over the effect of randomness in moist convection in terms of TC formation and predictability. A byproduct of tropical cyclones under vertical wind shear is the secondary eyewall formation (SEF). It is found that the eyewall formation is more often observed in TCs with moderate to high shear, which was inherently more unpredictable. The inward contraction/axisymmeterization of shear

  4. Promoting the confluence of tropical cyclone research.

    PubMed

    Marler, Thomas E

    2015-01-01

    Contributions of biologists to tropical cyclone research may improve by integrating concepts from other disciplines. Employing accumulated cyclone energy into protocols may foster greater integration of ecology and meteorology research. Considering experienced ecosystems as antifragile instead of just resilient may improve cross-referencing among ecological and social scientists. Quantifying ecosystem capital as distinct from ecosystem services may improve integration of tropical cyclone ecology research into the expansive global climate change research community.

  5. Tropical Cyclone Wave and Intensity Forecasts

    DTIC Science & Technology

    2009-09-30

    conclusion cannot be reached for Cyclone Nargis in the Northern Indian Ocean in 2008. Nargis has a two-day period when the NOGAPS and JTWC forecasts...1 DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. Tropical Cyclone Wave and Intensity Forecasts Charles...improve guidance for the prediction of waves and intensity associated with tropical cyclones . OBJECTIVES The objectives of this project are to

  6. Promoting the confluence of tropical cyclone research

    PubMed Central

    Marler, Thomas E

    2015-01-01

    Contributions of biologists to tropical cyclone research may improve by integrating concepts from other disciplines. Employing accumulated cyclone energy into protocols may foster greater integration of ecology and meteorology research. Considering experienced ecosystems as antifragile instead of just resilient may improve cross-referencing among ecological and social scientists. Quantifying ecosystem capital as distinct from ecosystem services may improve integration of tropical cyclone ecology research into the expansive global climate change research community. PMID:26480001

  7. Interactions between climate and tropical cyclones

    NASA Astrophysics Data System (ADS)

    Webster, P. J.

    2007-05-01

    For the last 50 years, there have been two major thrusts in tropical cyclone research: determining the state of the atmosphere and ocean that is suitable for the formation of tropical storms (the genesis criteria) and short-term forecasting of the track and intensity of storms. Efforts to forecast seasonal storm activity, especially in the North Atlantic Ocean, have been undertaken through empirical means and, more recently, using low-resolution climate models. Climate model results have been exceptionally encouraging suggesting that the tropical cyclogenesis factors are predictable and are part of the large scale tropical circulation. During the last few years, a spate of papers has noted the relationship between changes in sea-surface temperature (SST) and tropical cyclone intensity and frequency. A critical issue is determining to what degree the frequency of hurricanes, as well as their intensity distribution, will change in a warming world. We discuss recent research regarding the interactions of the climate system with tropical cyclones, including the role of climate in determining the genesis of tropical cyclones and the role of tropical cyclones in the heat balance of the planet. Specifically: (i) We re-examine the genesis criteria of tropical cyclones and add two new criteria based on the behavior of waves in a flow varying in longitude and the inertial instability of equatorial flow in a cross-equatorial pressure gradient environment. Tropical cyclones are seen to form where the stretching deformation is negative and where large-scale waves transform into tight smaller and highly energetic scale vortices. We also discuss the tendency for storms to develop and intensify where the near-equatorial flow is inertially unstable. (ii) Tropical cyclones act to cool the tropical oceans by > 1K/year by evaporation of ocean surface water and by entrainment mixing with cooler water from below the mixed layer. We suggest that tropical cyclones are important part of

  8. LCSs in tropical cyclone genesis

    NASA Astrophysics Data System (ADS)

    Rutherford, B.; Montgomery, M. T.

    2011-12-01

    The formation of tropical cyclones in the Atlantic most often occurs at the intersection of the wave trough axis of a westward propagating African easterly wave and the wave critical latitude. Viewed in a moving reference frame with the wave, a cat's eye region of cyclonic recirculation can be seen in streamlines prior to genesis. The cat's eye recirculation region has little strain deformation and its center serves as the focal point for aggregation of convectively generated vertical vorticity. Air inside the cat's eye is repeatedly moistened by convection and is protected from the lateral intrusion of dry air. Since the flow is inherently time-dependent, we contrast the time-dependent structures with Eulerian structures of the wave-relative frame. Time-dependence complicates the kinematic structure of the recirculation region as air masses from the outer environment are allowed to interact with the interior of the cat's eye. LCSs show different boundaries of the cat's eye than the streamlines in the wave-relative frame. These LCSs are particularly important for showing the pathways of air masses that interact with the developing vortex, as moist air promotes development by supporting deep convection, while interaction with dry air impedes development. We primarily use FTLEs to locate the LCSs, and show the role of LCSs in both developing and non-developing storms. In addition, we discuss how the vertical coherence of LCSs is important for resisting the effects of vertical wind shear.

  9. Lagrangian Vortices in Developing Tropical Cyclones

    DTIC Science & Technology

    2015-06-25

    cyclones B. Rutherford,a* T. J. Dunkertona and M. T. Montgomeryb aNorthwest Research Associates, Redmond, WA, USA bNaval Postgraduate School, Monterey...article has been contributed to by a US Government employee and his work is in the public domain in the USA. Tracking pre-genesis tropical cyclones is...season. All of the Lagrangian coherent structures that can be identified by this field are shown for developing disturbances and mature cyclones . The

  10. GPM Rain Rates in Tropical Cyclone Pam

    NASA Image and Video Library

    NASA-JAXA's GPM Satellite Close-up of Cyclone Pam's Rainfall NASA-JAXA's GPM core satellite captured rain rates in Tropical Cyclone Pam at 03:51 UTC (2:51 p.m. local time) on March 14, 2015. Heavie...

  11. Human Influence on Tropical Cyclone Intensity

    NASA Technical Reports Server (NTRS)

    Sobel, Adam H.; Camargo, Suzana J.; Hall, Timothy M.; Lee, Chia-Ying; Tippett, Michael K.; Wing, Allison A.

    2016-01-01

    Recent assessments agree that tropical cyclone intensity should increase as the climate warms. Less agreement exists on the detection of recent historical trends in tropical cyclone intensity.We interpret future and recent historical trends by using the theory of potential intensity, which predicts the maximum intensity achievable by a tropical cyclone in a given local environment. Although greenhouse gas-driven warming increases potential intensity, climate model simulations suggest that aerosol cooling has largely canceled that effect over the historical record. Large natural variability complicates analysis of trends, as do poleward shifts in the latitude of maximum intensity. In the absence of strong reductions in greenhouse gas emissions, future greenhouse gas forcing of potential intensity will increasingly dominate over aerosol forcing, leading to substantially larger increases in tropical cyclone intensities.

  12. Tropical Cyclone Jack in Satellite 3-D

    NASA Image and Video Library

    This 3-D flyby from NASA's TRMM satellite of Tropical Cyclone Jack on April 21 shows that some of the thunderstorms were shown by TRMM PR were still reaching height of at least 17 km (10.5 miles). ...

  13. Human influence on tropical cyclone intensity

    NASA Astrophysics Data System (ADS)

    Sobel, Adam H.; Camargo, Suzana J.; Hall, Timothy M.; Lee, Chia-Ying; Tippett, Michael K.; Wing, Allison A.

    2016-07-01

    Recent assessments agree that tropical cyclone intensity should increase as the climate warms. Less agreement exists on the detection of recent historical trends in tropical cyclone intensity. We interpret future and recent historical trends by using the theory of potential intensity, which predicts the maximum intensity achievable by a tropical cyclone in a given local environment. Although greenhouse gas-driven warming increases potential intensity, climate model simulations suggest that aerosol cooling has largely canceled that effect over the historical record. Large natural variability complicates analysis of trends, as do poleward shifts in the latitude of maximum intensity. In the absence of strong reductions in greenhouse gas emissions, future greenhouse gas forcing of potential intensity will increasingly dominate over aerosol forcing, leading to substantially larger increases in tropical cyclone intensities.

  14. Tropical Cyclone Yasi Spins Through Australia Interior

    NASA Image and Video Library

    2011-02-04

    The Atmospheric Infrared Sounder AIRS instrument onboard NASA Aqua spacecraft captured this infrared image of Tropical Cyclone Yasi on Feb. 2, 2011 as the storm passed over Australia Great Dividing Range.

  15. GPM Flyby of Tropical Cyclone Uriah

    NASA Image and Video Library

    On Feb. 15, GPM saw rain was falling at a rate of over 127 mm (5 inches) per hour in a band of intense storms south of Tropical Cyclone Uriah's center. Thunderstorms moving around the southwestern ...

  16. Human Influence on Tropical Cyclone Intensity

    NASA Technical Reports Server (NTRS)

    Sobel, Adam H.; Camargo, Suzana J.; Hall, Timothy M.; Lee, Chia-Ying; Tippett, Michael K.; Wing, Allison A.

    2016-01-01

    Recent assessments agree that tropical cyclone intensity should increase as the climate warms. Less agreement exists on the detection of recent historical trends in tropical cyclone intensity.We interpret future and recent historical trends by using the theory of potential intensity, which predicts the maximum intensity achievable by a tropical cyclone in a given local environment. Although greenhouse gas-driven warming increases potential intensity, climate model simulations suggest that aerosol cooling has largely canceled that effect over the historical record. Large natural variability complicates analysis of trends, as do poleward shifts in the latitude of maximum intensity. In the absence of strong reductions in greenhouse gas emissions, future greenhouse gas forcing of potential intensity will increasingly dominate over aerosol forcing, leading to substantially larger increases in tropical cyclone intensities.

  17. Human influence on tropical cyclone intensity.

    PubMed

    Sobel, Adam H; Camargo, Suzana J; Hall, Timothy M; Lee, Chia-Ying; Tippett, Michael K; Wing, Allison A

    2016-07-15

    Recent assessments agree that tropical cyclone intensity should increase as the climate warms. Less agreement exists on the detection of recent historical trends in tropical cyclone intensity. We interpret future and recent historical trends by using the theory of potential intensity, which predicts the maximum intensity achievable by a tropical cyclone in a given local environment. Although greenhouse gas-driven warming increases potential intensity, climate model simulations suggest that aerosol cooling has largely canceled that effect over the historical record. Large natural variability complicates analysis of trends, as do poleward shifts in the latitude of maximum intensity. In the absence of strong reductions in greenhouse gas emissions, future greenhouse gas forcing of potential intensity will increasingly dominate over aerosol forcing, leading to substantially larger increases in tropical cyclone intensities.

  18. Tropical Cyclone Formation/Structure/Motion Studies

    DTIC Science & Technology

    2006-09-30

    forecasts of certain physical parameters (e.g., vertical wind shear, mid-level warm core, low-level vorticity). Conditional probabilities defined the...vorticity fields and temperature data derived from polar-orbiting satellites (Vancas 2006). The presence of warm , moist air advected to the east of the...tropical cyclone (Figure 6a) caused the low- level warm anomaly to be shifted east of the tropical cyclone (Figure 6b). The combination of the

  19. Animation of Flood Potential from Two Australian Tropical Cyclones

    NASA Image and Video Library

    Merged precipitation data from NASA-JAXA's Tropical Rainfall Measuring Mission (TRMM) and other satellites was used to calculate flood potential withrainfall from Tropical Cyclone Lam and Tropical ...

  20. NASA CYGNSS Tropical Cyclone Mission

    NASA Astrophysics Data System (ADS)

    Ruf, Chris; Atlas, Robert; Majumdar, Sharan; Ettammal, Suhas; Waliser, Duane

    2017-04-01

    The NASA Cyclone Global Navigation Satellite System (CYGNSS) mission consists of a constellation of eight microsatellites that were launched into low-Earth orbit on 15 December 2016. Each observatory carries a four-channel bistatic scatterometer receiver to measure near surface wind speed over the ocean. The transmitter half of the scatterometer is the constellation of GPS satellites. CYGNSS is designed to address the inadequacy in observations of the inner core of tropical cyclones (TCs) that result from two causes: 1) much of the TC inner core is obscured from conventional remote sensing instruments by intense precipitation in the eye wall and inner rain bands; and 2) the rapidly evolving (genesis and intensification) stages of the TC life cycle are poorly sampled in time by conventional polar-orbiting, wide-swath surface wind imagers. The retrieval of wind speed by CYGNSS in the presence of heavy precipitation is possible due to the long operating wavelength used by GPS (19 cm), at which scattering and attenuation by rain are negligible. Improved temporal sampling by CYGNSS is possible due to the use of eight spacecraft with 4 scatterometer channels on each one. Median and mean revisit times everywhere in the tropics are 3 and 7 hours, respectively. Wind speed referenced to 10m height above the ocean surface is retrieved from CYGNSS measurements of bistatic radar cross section in a manner roughly analogous to that of conventional ocean wind scatterometers. The technique has been demonstrated previously from space by the UK-DMC and UK-TDS missions. Wind speed is retrieved with 25 km spatial resolution and an uncertainty of 2 m/s at low wind speeds and 10% at wind speeds above 20 m/s. Extensive simulation studies conducted prior to launch indicate that there will be a significant positive impact on TC forecast skill for both track and intensity with CYGNSS measurements assimilated into HWRF numerical forecasts. Simulations of CYGNSS spatial and temporal sampling

  1. Raindrop Size Distribution Measurements in Tropical Cyclones

    NASA Technical Reports Server (NTRS)

    Tokay, Ali; Bashor, Paul G.; Habib, Emad; Kasparis, Takis

    2008-01-01

    Characteristics of the raindrop size distribution in seven tropical cyclones have been studied through impact-type disdrometer measurements at three different sites during the 2004-06 Atlantic hurricane seasons. One of the cyclones has been observed at two different sites. High concentrations of small and/or midsize drops were observed in the presence or absence of large drops. Even in the presence of large drops, the maximum drop diameter rarely exceeded 4 mm. These characteristics of raindrop size distribution were observed in all stages of tropical cyclones, unless the storm was in the extratropical stage where the tropical cyclone and a midlatitude frontal system had merged. The presence of relatively high concentrations of large drops in extratropical cyclones resembled the size distribution in continental thunderstorms. The integral rain parameters of drop concentration, liquid water content, and rain rate at fixed reflectivity were therefore lower in extratropical cyclones than in tropical cyclones. In tropical cyclones, at a disdrometercalculated reflectivity of 40 dBZ, the number concentration was 700 plus or minus 100 drops m(sup -3), while the liquid water content and rain rate were 0.90 plus or minus 0.05 g m(sup -3) and 18.5 plus or minus 0.5 mm h(sup -1), respectively. The mean mass diameter, on the other hand, was 1.67 plus or minus 0.3 mm. The comparison of raindrop size distributions between Atlantic tropical cyclones and storms that occurred in the central tropical Pacific island of Roi-Namur revealed that the number density is slightly shifted toward smaller drops, resulting in higher-integral rain parameters and lower mean mass and maximum drop diameters at the latter site. Considering parameterization of the raindrop size distribution in tropical cyclones, characteristics of the normalized gamma distribution parameters were examined with respect to reflectivity. The mean mass diameter increased rapidly with reflectivity, while the normalized

  2. Raindrop Size Distribution Measurements in Tropical Cyclones

    NASA Technical Reports Server (NTRS)

    Tokay, Ali; Bashor, Paul G.; Habib, Emad; Kasparis, Takis

    2008-01-01

    Characteristics of the raindrop size distribution in seven tropical cyclones have been studied through impact-type disdrometer measurements at three different sites during the 2004-06 Atlantic hurricane seasons. One of the cyclones has been observed at two different sites. High concentrations of small and/or midsize drops were observed in the presence or absence of large drops. Even in the presence of large drops, the maximum drop diameter rarely exceeded 4 mm. These characteristics of raindrop size distribution were observed in all stages of tropical cyclones, unless the storm was in the extratropical stage where the tropical cyclone and a midlatitude frontal system had merged. The presence of relatively high concentrations of large drops in extratropical cyclones resembled the size distribution in continental thunderstorms. The integral rain parameters of drop concentration, liquid water content, and rain rate at fixed reflectivity were therefore lower in extratropical cyclones than in tropical cyclones. In tropical cyclones, at a disdrometercalculated reflectivity of 40 dBZ, the number concentration was 700 plus or minus 100 drops m(sup -3), while the liquid water content and rain rate were 0.90 plus or minus 0.05 g m(sup -3) and 18.5 plus or minus 0.5 mm h(sup -1), respectively. The mean mass diameter, on the other hand, was 1.67 plus or minus 0.3 mm. The comparison of raindrop size distributions between Atlantic tropical cyclones and storms that occurred in the central tropical Pacific island of Roi-Namur revealed that the number density is slightly shifted toward smaller drops, resulting in higher-integral rain parameters and lower mean mass and maximum drop diameters at the latter site. Considering parameterization of the raindrop size distribution in tropical cyclones, characteristics of the normalized gamma distribution parameters were examined with respect to reflectivity. The mean mass diameter increased rapidly with reflectivity, while the normalized

  3. Field theoretical prediction of a property of the tropical cyclone

    NASA Astrophysics Data System (ADS)

    Spineanu, F.; Vlad, M.

    2014-01-01

    The large scale atmospheric vortices (tropical cyclones, tornadoes) are complex physical systems combining thermodynamics and fluid-mechanical processes. The late phase of the evolution towards stationarity consists of the vorticity concentration, a well known tendency to self-organization , an universal property of the two-dimensional fluids. It may then be expected that the stationary state of the tropical cyclone has the same nature as the vortices of many other systems in nature: ideal (Euler) fluids, superconductors, Bose-Einsetin condensate, cosmic strings, etc. Indeed it was found that there is a description of the atmospheric vortex in terms of a classical field theory. It is compatible with the more conventional treatment based on conservation laws, but the field theoretical model reveals properties that are almost inaccessible to the conventional formulation: it identifies the stationary states as being close to self-duality. This is of highest importance: the self-duality is known to be the origin of all coherent structures known in natural systems. Therefore the field theoretical (FT) formulation finds that the cuasi-coherent form of the atmospheric vortex (tropical cyclone) at stationarity is an expression of this particular property. In the present work we examine a strong property of the tropical cyclone, which arises in the FT formulation in a natural way: the equality of the masses of the particles associated to the matter field and respectively to the gauge field in the FT model is translated into the equality between the maximum radial extension of the tropical cyclone and the Rossby radius. For the cases where the FT model is a good approximation we calculate characteristic quantities of the tropical cyclone and find good comparison with observational data.

  4. The tropical cyclone diurnal cycle

    NASA Astrophysics Data System (ADS)

    Dunion, Jason P.

    The research presented in this thesis explores a phenomenon referred to as the tropical cyclone (TC) diurnal cycle (TCDC) and presents satellite, numerical modeling, and observational perspectives pertaining to how it can be monitored, its evolution in time and space, its relevance to TC structure and intensity, and how it manifests in numerical simulations of TCs. Infrared satellite imagery was developed and used to investigate diurnal oscillations in TCs and finds a diurnal pulsing pattern that occurs with notable regularity through a relatively deep layer from the inner core to the surrounding environment. A combination of satellite, numerical model simulations, and aircraft observations found diurnal signals in operationally analyzed radii of 50 kt winds in TCs and in satellite intensity estimates from the Advanced Dvorak Technique and spawned the development of a 24-hr conceptual clock that approximates the temporal and spatial evolution of the TCDC each day. TC diurnal pulses are revealed to significantly impact the thermodynamics and winds in the TC environment and appear as narrow, convectively active rings of high radar reflectivity in NOAA aircraft radar data and are hundreds of kilometers in length. Enhanced nighttime radiational cooling that is particularly favored in the TC outflow layer acts to pre-condition the TC environment in a way that favors triggering of the TCDC and TC diurnal pulses, while in the daytime, the stabilizing effects of shortwave warming begins to suppress TCDC processes in the storm, leading to the culmination of the TCDC each day. Schematics are presented that summarize many of the main findings in this work, including descriptions of the basic state of the TC environment as the TCDC evolves during its early and later stages each day and a TCDC-centric daytime evolution of a TC diurnal pulse, associated squall lines and gust fronts, and radial and vertical winds in the lower and upper levels of the storm. The TCDC represents a

  5. Topographic Rossby Waves Generated by Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Dukhovskoy, D. S.; Morey, S. L.

    2013-05-01

    Analytical and numerical studies suggest that given appropriate slope, the ocean responds to a tropical storm with low-frequency motions trapped over a continental slope, the Coastal Trapped Waves. The presented study is focused on Topographic Rossby Waves (TRW), sub-inertial oscillations propagating over a sloping bottom. Generation and propagation of TRW under barotropic (Continental Shelf Waves or Shelf Waves) and baroclinic (Bottom Trapped Waves) approximations are discussed. A real-case model study of a storm surge in Apalachee Bay, northeastern Gulf of Mexico during Hurricane Dennis (July, 2005) is presented to demonstrate the role of the shelf waves in coastal inundation. The presentation also discusses excitation of baroclinic bottom-intensified wave motions on the continental slope by a tropical cyclone. An idealized model experiment demonstrates that a continental shelf that (1) responds to a storm as a baroclinic ocean and (2) has a slope steep enough to dominate the planetary β-effect (but small enough to prevent internal Kelvin-type modes) can support baroclinic topographic waves.

  6. Next-Generation Tropical Cyclone Model

    DTIC Science & Technology

    2016-06-07

    goal of this project is to develop a robust and hardened high-resolution air -ocean coupled tropical cyclone (TC) data assimilation and prediction...cyclone (TC) model that can analyze, initialize, and predict TC position, structure and intensity, using a high-resolution (< 3 km) air -ocean coupled ...layers in the recent ONR-sponsored Coupled Boundary Layers/ Air Sea Transfer (CBLAST) project. In addition, we will leverage work performed over the past

  7. Asymmetric and axisymmetric dynamics of tropical cyclones

    NASA Astrophysics Data System (ADS)

    Persing, J.; Montgomery, M. T.; McWilliams, J. C.; Smith, R. K.

    2013-05-01

    We present the results of idealized numerical experiments to examine the difference between tropical cyclone evolution in three-dimensional (3-D) and axisymmetric (AX) model configurations. We focus on the prototype problem for intensification, which considers the evolution of an initially unsaturated AX vortex in gradient-wind balance on an f-plane. Consistent with findings of previous work, the mature intensity in the 3-D model is reduced relative to that in the AX model. In contrast with previous interpretations invoking barotropic instability and related horizontal mixing processes as a mechanism detrimental to the spin-up process, the results indicate that 3-D eddy processes associated with vortical plume structures can assist the intensification process by contributing to a radial contraction of the maximum tangential velocity and to a vertical extension of tangential winds through the depth of the troposphere. These plumes contribute significantly also to the azimuthally-averaged heating rate and the corresponding azimuthal-mean overturning circulation. The comparisons show that the resolved 3-D eddy momentum fluxes above the boundary layer exhibit counter-gradient characteristics and are generally not represented properly by the subgrid-scale parameterizations in the AX configuration. The resolved eddy fluxes act to support the contraction and intensification of the maximum tangential winds. The comparisons indicate fundamental differences between convective organization in the 3-D and AX configurations for meteorologically relevant forecast time scales. While the radial and vertical gradients of the system-scale angular rotation provide a hostile environment for deep convection in the 3-D model, with a corresponding tendency to strain the convective elements in the tangential direction, deep convection in the AX model does not suffer this tendency. Also, since during the 3-D intensification process the convection has not yet organized into annular rings

  8. Asymmetric and axisymmetric dynamics of tropical cyclones

    NASA Astrophysics Data System (ADS)

    Persing, J.; Montgomery, M. T.; McWilliams, J. C.; Smith, R. K.

    2013-12-01

    We present the results of idealized numerical experiments to examine the difference between tropical cyclone evolution in three-dimensional (3-D) and axisymmetric (AX) model configurations. We focus on the prototype problem for intensification, which considers the evolution of an initially unsaturated AX vortex in gradient-wind balance on an f plane. Consistent with findings of previous work, the mature intensity in the 3-D model is reduced relative to that in the AX model. In contrast with previous interpretations invoking barotropic instability and related horizontal mixing processes as a mechanism detrimental to the spin-up process, the results indicate that 3-D eddy processes associated with vortical plume structures can assist the intensification process by contributing to a radial contraction of the maximum tangential velocity and to a vertical extension of tangential winds through the depth of the troposphere. These plumes contribute significantly also to the azimuthally averaged heating rate and the corresponding azimuthal-mean overturning circulation. The comparisons show that the resolved 3-D eddy momentum fluxes above the boundary layer exhibit counter-gradient characteristics during a key spin-up period, and more generally are not solely diffusive. The effects of these eddies are thus not properly represented by the subgrid-scale parameterizations in the AX configuration. The resolved eddy fluxes act to support the contraction and intensification of the maximum tangential winds. The comparisons indicate fundamental differences between convective organization in the 3-D and AX configurations for meteorologically relevant forecast timescales. While the radial and vertical gradients of the system-scale angular rotation provide a hostile environment for deep convection in the 3-D model, with a corresponding tendency to strain the convective elements in the tangential direction, deep convection in the AX model does not suffer this tendency. Also, since

  9. Raindrop Size Distribution Measurements in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Tokay, A.; Bashor, P. G.; Habib, E.; Kasparis, T. C.

    2006-12-01

    Measurements of the raindrop size distribution (RSD) have been collected in tropical cyclones and hurricanes with an impact type disdrometer during the past three Atlantic hurricane seasons. The measurements were taken at Wallops Island, Virginia, Lafayette, Louisiana, and Orlando, Florida. The RSDs from the remnants of tropical cyclones or hurricanes at 40 dBZ agreed well with each other where the mean mass diameter was 1.65-1.7 mm, and the total concentration had a range of 600 to 800 drops/m3. Assuming the normalized gamma size distribution, the shape parameter will be 5-8 to satisfy the observed rain rate of 18-20 mm/hr. If the observations were taken during the extratropical phase of the storm where the tropical cyclone merges with a frontal system, the composite spectra at 40 dBZ include more large drops and less small to mid-size drops, typical for continental thunderstorms. Thus, the mean mass diameter was larger, while total concentration, and rain rate was less in extratropical cyclones than in tropical cyclones.

  10. Tropical Cyclone Bejisa Near Madagascar

    NASA Image and Video Library

    NASA's TRMM satellite flew over Cyclone Bejisa on December 29, 2013 at 1507 UTC. This 3-D animation of TRMM data revealed strong thunderstorms around Bejisa's center were reaching heights above 16....

  11. Tropical Cyclones Affecting Guam (1671-1980).

    DTIC Science & Technology

    1983-09-01

    with at least 34 knot maximum winds and one developing tropical cyclone - Irma , Judy, Kit, Ora and Tropical Depression 31 (later known as Nina) - all...cyclones passed within 120 nm of Agana. 23 A o . ° . ’ . . . - . . . . . . . In all cases except Karen (November 1962), Irma (February 1953) and Vernon...AMY MAY 1971 9.92 Taguac SSW 90 T.S. IDA OCT 1969 9.38 Taguac NNE 90 T.S. IRMA FEB 1953 7.88 Andersen AFB S 90 T.D. POLLY AUG 1971 7.81 Taguac NNE 85

  12. Annual Tropical Cyclone Report 2011

    DTIC Science & Technology

    2012-05-24

    ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for...operationally or meteorologically significant cyclones noted within the JTWC Area of Responsibility. Details are provided to describe operational impacts...trend that started in 2005, with only 27 TCs observed compared to the long term average of 31. Unlike the previous year, there were four cyclones that

  13. Tropical cyclone activity over the Southwest Tropical Indian Ocean

    NASA Astrophysics Data System (ADS)

    Burns, Jessica M.; Subrahmanyam, Bulusu; Nyadjro, Ebenezer S.; Murty, V. S. N.

    2016-08-01

    The Southwest Tropical Indian Ocean (SWTIO) is a key region for air-sea interaction. Tropical cyclones (TCs) regularly form over the SWTIO and subsurface ocean variability influences the cyclogenesis of this region. Tropical cyclone days for this region span from November through April, and peak in January and February during austral summer. Past research provides evidence for more tropical cyclone days over the SWTIO during austral summer (December-June) with a deep thermocline ridge than in austral summer with a shallow thermocline ridge. We have analyzed the Argo temperature data and HYbrid Coordinate Ocean Model (HYCOM) outputs while focusing on the austral summer of 2012/2013 (a positive Indian Ocean Dipole (IOD) year and neutral El Niño Southern Oscillation (ENSO) year) when seven named tropical cyclones developed over the SWTIO region. This study reveals that the climatic events like the IOD and ENSO influence the cyclonic activity and number of TC days over the SWTIO. We ascertain that the IOD events have linkages with the Barrier Layer Thickness (BLT) in the SWTIO region through propagating Rossby waves, and further show that the BLT variability influences the cyclonic activity in this region.

  14. Citizen scientists analyzing tropical cyclone intensities

    NASA Astrophysics Data System (ADS)

    Hennon, Christopher C.

    2012-10-01

    A new crowd sourcing project called CycloneCenter enables the public to analyze historical global tropical cyclone (TC) intensities. The primary goal of CycloneCenter, which launched in mid-September, is to resolve discrepancies in the recent global TC record arising principally from inconsistent development of tropical cyclone intensity data. The historical TC record is composed of data sets called "best tracks," which contain a forecast agency's best assessment of TC tracks and intensities. Best track data have improved in quality since the beginning of the geostationary satellite era in the 1960s (because TCs could no longer disappear from sight). However, a global compilation of best track data (International Best Track Archive for Climate Stewardship (IBTrACS)) has brought to light large interagency differences between some TC best track intensities, even in the recent past [Knapp et al., 2010Knapp et al., 2010]. For example, maximum wind speed estimates for Tropical Cyclone Gay (1989) differed by as much as 70 knots as it was tracked by three different agencies.

  15. Tropical cyclone Pam field survey in Vanuatu

    NASA Astrophysics Data System (ADS)

    Fritz, Hermann M.; Pilarczyk, Jessica E.; Kosciuch, Thomas; Hong, Isabel; Rarai, Allan; Harrison, Morris J.; Jockley, Fred R.; Horton, Benjamin P.

    2016-04-01

    Severe tropical cyclone Pam (Cat. 5, SSHS) crossed the Vanuatu archipelago with sustained winds of 270 km/h on March 13 and 14, 2015 and made landfall on Erromango. Pam is the most intense tropical cyclone to make landfall on Vanuatu since the advent of satellite imagery based intensity estimates in the 1970s. Pam caused one of the worst natural disaster in Vanuatu's recorded history. Eleven fatalities were directly attributed to cyclone Pam and mostly due to lack of shelter from airborne debris. On March 6 Pam formed east of the Santa Cruz Islands causing coastal inundation on Tuvalu's Vaitupu Island located some 1100 km east of the cyclone center. Pam intensified while tracking southward along Vanuatu severely affecting the Shefa and Tafea Provinces. An international storm surge reconnaissance team was deployed to Vanuatu from June 3 to 17, 2015 to complement earlier local surveys. Cyclone Pam struck a remote island archipelago particularly vulnerable to the combined cyclonic multi-hazards encompassing extreme wind gusts, massive rainfall and coastal flooding due to a combination of storm surge and storm wave impacts. The team surveyed coastal villages on Epi, the Shepherd Islands (Tongoa and Mataso), Efate (including Lelepa), Erromango, and Tanna. The survey spanned 320 km parallel to the cyclone track between Epi and Tanna encompassing more than 45 sites including the hardest hit settlements. Coastal flooding profiles were surveyed from the shoreline to the limit of inundation. Maximum coastal flood elevations and overland flow depths were measured based on water marks on buildings, scars on trees, rafted debris and corroborated with eyewitness accounts. We surveyed 91 high water marks with characteristic coastal flood levels in the 3 to 7 m range and composed of storm surge with superimposed storm waves. Inundation distances were mostly limited to a few hundred meters but reached 800 m on Epi Island. Wrack lines containing pumice perfectly delineated the

  16. Modeling the impact of land surface feedbacks on post landfall tropical cyclones

    NASA Astrophysics Data System (ADS)

    Subramanian, Subashini

    The land surface is an important component of numerical models. The land surface models are modules that control energy partitioning, compute surface exchange coefficients and form the only physical boundary in a regional scale numerical model. Thus, an accurate representation of land surface is critical to compute surface fluxes, represent the boundary layer evolution and affect changes in weather systems. Land surface can affect landfalling tropical cyclones in two ways: (i) when the cyclone is offshore and land can influence cyclones by introducing dry (or moist) air that can weaken (or strengthen) the organized convective structure of cyclones, and (ii) land can affect the evolution of cyclones post landfall by modifying the surface heat fluxes and introducing additional surface drag. In this dissertation, the hypothesis that improved representation of land surface conditions will improve the prediction of landfalling tropical cyclones is tested. To that effect, a comprehensive review of land surface effects on tropical cyclones was undertaken and an idealized study was conducted to study the impact of antecedent soil temperature on the sustenance/reintensification of tropical cyclones over land. Rainfall verification for cyclone events over the Atlantic Ocean was conducted and a comparison study between land models--GFDL Slab and Noah, also considers the sensitivity of tropical cyclone models to land surface parameterizations. The recent adoption of Noah land model with hydrology products in HWRF offers a unique opportunity to couple a river routing model to HWRF to provide streamflow estimations from the HWRF model and this dissertation has outlined techniques to real time predict streamflow for United States with HWRF forcing. Results from this dissertation research indicate antecedent land surface conditions can affect tropical cyclone evolution post landfall and high soil temperature and thermally diffusive soil texture of land surface are critical factors

  17. Internal Influences on Tropical Cyclone Formation

    DTIC Science & Technology

    2006-01-01

    scales. This is evident in Fig. 2. Another hypothesis in the top-down category is what we call the “ shower - head” theory by Bister and Emanuel...extra-tropical precursors. Quart. J. Roy. Meteor . Soc. (coming soon). Dickinson, M.J., and J. Molinari, 2002: Mixed Rossby-gravity waves and...1998: The formation of Tropical Cyclones. Meteor . Atmos. Phys. 67, 37—69. Harr, P. A., M. S. Kalafsky and R. L. Elsberry, 1996a: Environmental

  18. Objective classification of historical tropical cyclone intensity

    NASA Astrophysics Data System (ADS)

    Chenoweth, Michael

    2007-03-01

    Preinstrumental records of historical tropical cyclone activity require objective methods for accurately categorizing tropical cyclone intensity. Here wind force terms and damage reports from newspaper accounts in the Lesser Antilles and Jamaica for the period 1795-1879 are compared with wind speed estimates calculated from barometric pressure data. A total of 95 separate barometric pressure readings and colocated simultaneous wind force descriptors and wind-induced damage reports are compared. The wind speed estimates from barometric pressure data are taken as the most reliable and serve as a standard to compare against other data. Wind-induced damage reports are used to produce an estimated wind speed range using a modified Fujita scale. Wind force terms are compared with the barometric pressure data to determine if a gale, as used in the contemporary newspapers, is consistent with the modern definition of a gale. Results indicate that the modern definition of a gale (the threshold point separating the classification of a tropical depression from a tropical storm) is equivalent to that in contemporary newspaper accounts. Barometric pressure values are consistent with both reported wind force terms and wind damage on land when the location, speed and direction of movement of the tropical cyclone are determined. Damage reports and derived wind force estimates are consistent with other published results. Biases in ships' logbooks are confirmed and wind force terms of gale strength or greater are identified. These results offer a bridge between the earlier noninstrumental records of tropical cyclones and modern records thereby offering a method of consistently classifying storms in the Caribbean region into tropical depressions, tropical storms, nonmajor and major hurricanes.

  19. Reanalyzing Tropical Cyclone Intensities with Citizen Scientists

    NASA Astrophysics Data System (ADS)

    Schreck, C. J.; Hennon, C. C.; Knapp, K.; Stevens, S. E.

    2012-12-01

    Tropical cyclones are among the most destructive weather phenomena. Whenever possible, the intensities of these storms have been determined from in situ data or aircraft reconnaissance. More often, however, they are estimated subjectively from satellite data using the Dvorak technique. Heterogeneities are introduced into the historical record with the evolution of operational procedures, personnel, and observing platforms. In some cases, multiple agencies even arrive at different estimates for the same storm. These uncertainties impede our ability to identify the relationship between tropical cyclone intensities and climate change. NOAA's NCDC has produced a 30-year (1979-2008) homogeneous dataset (HURSAT) of tropical cyclone imagery from geostationary satellites. This dataset has the potential to address some of the uncertainties in the recent tropical cyclone record. However, it would take nearly 40 years for a trained expert, working nonstop, to apply the Dvorak technique to all 200,000 images. Harnessing the power of thousands of Citizen Scientists, the same task can be completed in a matter of months. This presentation will explain how the Dvorak technique was adapted for Citizen Scientists, and how their skill will be evaluated relative to the operational analyses by trained experts.

  20. Assessment of Tropical Cyclone Structure Variability

    DTIC Science & Technology

    2013-09-01

    creates an unfavorable environment to sustain deep convection, and thus supported the formation of a moat (a weak- echo region outside the primary...of advanced microwave sounder unit tropical cyclone intensity and size estimation algorithms. J. Appl. Meteor., 45, 1573—1581. Depperman, C. E., 1947

  1. The Indian Ocean Dipole's influence on Atlantic tropical cyclone activity

    NASA Astrophysics Data System (ADS)

    Marinaro, Alan Joseph

    Improving early tropical cyclone forecasts would assist reinsurance decision makers as they seek information that can minimize risks. Early lead forecasts are based on model variables before December 1 (Year 0) that predict Atlantic tropical cyclone activity (Year +1). The autumn Indian Ocean Dipole (IOD) has an 8 to 14 month antecedent correlation with the El Nino - Southern Oscillation (ENSO). ENSO is traditionally the best non-lead and overall predictor of Atlantic tropical cyclone activity. Analyses were performed over a 30-year period from 1984/85-2013/14, with some time variation depending on the test. Correlation, spatial, and wavelet analyses were utilized to find associations between the IOD, west and east components of the IOD, and four other variables related to the following season's ENSO state and tropical cyclone activity. The prior western pole of the October IOD (WIOD) was demonstrated to have statistically significant r-squared values (i.e. 99% confidence interval) to upcoming tropical storm activity (i.e. explained 25% of the variance), named storm counts (28%), and ENSO (21%). The WIOD has no connection with U.S. hurricane landfalls. Wavelet analysis between October IOD variables and following August-October ENSO data was observed to have the best time-frequency relationship. Dynamic reasoning for these relationships reside within the idealized biennial IOD-ENSO cycle, Walker circulation process, and the impact of ENSO on the state of the Atlantic Basin. The WIOD's integration into early-lead forecast models could be an advantage for those in the reinsurance industry and other decision makers impacted by Atlantic tropical cyclonesn.

  2. Mesoscale Processes In Tropical Cyclones

    DTIC Science & Technology

    2000-09-30

    have shown that invoking the spray parameterizations of Fairall et al (1995) and Andreas and DeCosmo (1999) produce radically different results. In...cyclone intensity. Aust. Meteor. Mag. , 48, 147-152. Leslie, L.M. and Speer , M.S., 1998: Comments on short range ensemble forecasting of explosive...Australian east coast cyclogenesis, Wea. Forec, 12, 1209-1211. Leslie, L.M. and Speer , M.S., 1998: Short range ensemble forecasting of explosive Australian

  3. Model finds bigger, stronger tropical cyclones with warming seas

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2014-03-01

    In the wake of powerful tropical cyclones such as Hurricanes Sandy and Katrina and Typhoon Haiyan, questions about the likely effect of climate change on tropical cyclone activity are on the public's mind. The interactions between global warming and cyclone activity, however, are complex, with rising sea surface temperatures, changing energy distributions, and altered atmospheric dynamics all having some effect.

  4. Tropical cyclone rainfall area controlled by relative sea surface temperature

    PubMed Central

    Lin, Yanluan; Zhao, Ming; Zhang, Minghua

    2015-01-01

    Tropical cyclone rainfall rates have been projected to increase in a warmer climate. The area coverage of tropical cyclones influences their impact on human lives, yet little is known about how tropical cyclone rainfall area will change in the future. Here, using satellite data and global atmospheric model simulations, we show that tropical cyclone rainfall area is controlled primarily by its environmental sea surface temperature (SST) relative to the tropical mean SST (that is, the relative SST), while rainfall rate increases with increasing absolute SST. Our result is consistent with previous numerical simulations that indicated tight relationships between tropical cyclone size and mid-tropospheric relative humidity. Global statistics of tropical cyclone rainfall area are not expected to change markedly under a warmer climate provided that SST change is relatively uniform, implying that increases in total rainfall will be confined to similar size domains with higher rainfall rates. PMID:25761457

  5. 1993 Annual Tropical Cyclone Report

    DTIC Science & Technology

    1995-01-01

    Cover Caption: As viewed on 301604Z September by the Andersen AFB, Guam Next Generation (Doppler W-ther) Radar ( NEXRAD ), the bands of precipitation...basis for our analyses, forecasts and post analyses; the staff at National Oceanic and Atmospheric Administration ( NOAA ) National Environmental Satellite...Doppler Weather Radar’s ( NEXRAD ) introduction to tropical meteorology. Depicted on the cover graphic is Tropical Storm Ed seen from the Guam NEXRAD

  6. A Simplified Model of Tropical Cyclone Intensification

    NASA Astrophysics Data System (ADS)

    Schubert, W. H.

    2015-12-01

    An axisymmetric model of tropical cyclone intensification is presented. The model is based on Salmon's wave-vortex approximation, which can describe flows with high Rossby number and low Froude number. After introducing an additional approximation designed to filter propagating inertia-gravity waves, the problem is reduced to the prediction of potential vorticity (PV) and the inversion of this PV to obtain the balanced wind and mass fields. This PV prediction/inversion problem is solved analytically for two types of forcing: a two-region model in which there is nonzero forcing in the cyclone core and zero forcing in the far-field; a three-region model in which there is non-zero forcing in both the cyclone core and the eyewall, with zero forcing in the far-field. The solutions of the two-region model provide insight into why tropical cyclones can have long incubation times before rapid intensification and how the size of the mature vortex can be influenced by the size of the initial vortex. The solutions of the three-region model provide insight into the formation of hollow PV structures and the inward movement of angular momentum surfaces across the radius of maximum wind.

  7. Cyclone Center: Insights on Historical Tropical Cyclones from Citizen Volunteers

    NASA Astrophysics Data System (ADS)

    Thorne, P.; Hennon, C. C.; Knapp, K. R.; Schreck, C. J., III; Stevens, S. E.; Kossin, J. P.; Rennie, J.; Hennon, P. A.; Kruk, M. C.

    2015-12-01

    The cyclonecenter.org project started in fall 2012 and has been collecting citizen scientist volunteer tropical cyclone intensity estimates ever since. The project is hosted by the Citizen Science Alliance (zooniverse) and the platform is supported by a range of scientists. We have over 30 years of satellite imagery of tropical cyclones but the analysis to date has been done on an ocean-basin by ocean-basin basis and worse still practices have changed over time. We therefore do not, presently, have a homogeneous record relevant for discerning climatic changes. Automated techniques can classify many of the images but have a propensity to be challenged during storm transitions. The problem is fundamentally one where many pairs of eyes are invaluable as there is no substitute for human eyes in discerning patterns. Each image is classified by ten unique users before it is retired. This provides a unique insight into the uncertainty inherent in classification. In the three years of the project much useful data has accrued. This presentation shall highlight some of the results and analyses to date and touch on insights as to what has worked and what perhaps has not worked so well. There are still many images left to complete so its far from too late to jump over to www.cyclonecenter.org and help out.

  8. Toward Clarity on Understanding Tropical Cyclone Intensification

    DTIC Science & Technology

    2015-08-01

    historically as the prototype configuration for understanding basic aspects of tropical cyclone intensification not involving strong interactions with the...storm environment. The four paradigms re- viewed are 1) the CISK1 paradigm, 2) the cooperative intensification paradigm, 3) a thermodynamic air–sea...boundary layer model to predict the radial profiles of vertical velocity and thermodynamic quantities at the top of the boundary layer. However, this

  9. Ensemble Prediction of Tropical Cyclone Genesis

    DTIC Science & Technology

    2017-02-23

    operational TC genesis forecast model. Recent studies show that numerical models with grid size near 10 km and explicitly resolved cloud schemes are...efficiency: Mid-level versus bottom vortex Cloud resolving WRF model is used to investigate the tropical cyclone genesis efficiency in an...regardless of models used and the assumed global warming scenarios. These results highlight possible future increase in storm-related socio-economic

  10. Tropical Cyclone Readiness Conditions Setting Aids

    DTIC Science & Technology

    1987-04-01

    values for 90% and/or 95% confidence are given for 50 kt tropical cyclone and typhoon ( hurricane ) readiness conditions. The methodology used a large...number of computer-simulated forecasts for actual typhoons ( hurricanes ) that passed near Yokosuka, Buckner Bay, Apra Harbor, Cubi Point, or Pearl...8217 l^^^l."^.-^^^ ’ MATHEriA-T I CAl... MODELS , PH 1L1PPINES , LARN Ni^ DC (24) (ij; ID (25) ClHARmCyclDne Hurricane

  11. Understanding and Forecasting Tropical Cyclone Intensity Change

    NASA Astrophysics Data System (ADS)

    Fitzpatrick, Patrick James

    1995-01-01

    This research investigates several issues pertaining to tropical cyclone intensity change. Previous research on tropical cyclone intensity change is reviewed in great detail. The applicability of upper-level forcing theories is questioned. Inner-core processes related to intensity change are studied, with particular attention on the relationship between the vertical profile of the tangential wind (v _{t}) field in the eyewall region and future pressure changes. It is hypothesized that a vertically conserved wind profile is conducive to fast intensification. Observations support this theory. By stratifying inner-core data into fast and slow developers, it is shown that fast developing tropical cyclones contain a more vertically stacked inner-core vortex than slow developers. It is also shown that a direct correlation exists between inner -core upper-level winds and tropical cyclone intensification, with the rate of intensification proportional to the magnitude and symmetry of upper-level v_{t}. . An alternative air-sea interaction theory is presented which incorporates boundary layer cooling. The buoyancy calculations include partial water-loading and ice micro -physics, and their relevance to CAPE calculations in the tropics is discussed. It is shown that the lateral extension of the eye, above a sloping eyewall, is the crucial component in maintaining the air-sea interaction despite boundary layer cooling. Implications on the maximum intensity a storm may achieve are discussed. A multiple regression scheme with intensity change as the dependent variable has been developed. The new scheme is titled the Typhoon Intensity Prediction Scheme (TIPS), and is similar to one used operationally at the National Hurricane Center. However, TIPS contains two major differences: it is developed for the western North Pacific Ocean, and utilizes digitized satellite data. It is shown that the satellite data can distinguish between fast and slow developing tropical cyclones. The

  12. Combining Tropical Cyclone Data Sets Worldwide

    NASA Astrophysics Data System (ADS)

    Levinson, David H.; Diamond, Howard J.

    2009-09-01

    International Best Track Archive for Climate Stewardship (IBTrACS) Workshop; Asheville, North Carolina, 5-7 May 2009; At the International Best Track Archive for Climate Stewardship (IBTrACS) workshop in North Carolina, experts from the World Meteorological Organization's (WMO) officially recognized tropical cyclone tracking and forecasting agencies met to discuss ways to accurately combine the disparate tropical cyclone (TC) best track data to better understand their global climatology. Representatives from each participating agency provided an overview of their agency's operating procedures and how those procedures have changed over time. Breakout sessions addressed many issues, including wind-pressure relationships and their use, converting between wind speed averaging periods, and other differences between best track data sets. The need for a global reanalysis of tropical cyclones during the satellite era arose as a recurring theme in each session. Current best track data are heterogeneous by construction, and efforts to decrease data set differences can only go so far in ensuring spatiotemporal homogeneity. It was clear to the participants that such a global reanalysis would require a champion to coordinate efforts among agencies in each basin and to help secure the resources needed.

  13. Evolution of Tropical Cyclone Characteristics and Forecast Assessment

    DTIC Science & Technology

    2016-06-07

    cyclone formations over the tropical western North Pacific is 6.7 days. However, it is known that tropical cyclone formation occurs in clusters with... clustering of tropical cyclone activity are related to external and internal forcing mechanisms. External mechanisms are defined to act over larger space and...Therefore, the primary scientific objectives are to identify each external and internal mechanism and define how they influence the clustering of

  14. Evaluation of a Heuristic Model for Tropical Cyclone Resilience

    DTIC Science & Technology

    2015-01-26

    1 Evaluation of a Heuristic Model for Tropical Cyclone Resilience Paul D. Reasor1 and Michael T. Montgomery2 1NOAA/AOML/Hurricane...2015 to 00-00-2015 4. TITLE AND SUBTITLE Evaluation of a Heuristic Model for Tropical Cyclone Resilience 5a. CONTRACT NUMBER 5b. GRANT NUMBER...heuristic model for the 4 temporal evolution of the small-amplitude tilt of a tropical cyclone -like vortex under 5 vertical-shear forcing for both a dry and

  15. Modeling Interaction of a Tropical Cyclone with Its Cold Wake

    DTIC Science & Technology

    2014-09-01

    circulation crosses the cold wake. The energy input from the ocean to a tropical cyclone (TC) may be modulated by low sea-surface temperatures (SST... TROPICAL CYCLONE WITH ITS COLD WAKE by Sue Chen September 2014 Dissertation Supervisors: Patrick A. Harr Russell L. Elsberry THIS...4. TITLE AND SUBTITLE MODELING INTERACTION OF A TROPICAL CYCLONE WITH ITS COLD WAKE 5. FUNDING NUMBERS N/A 6. AUTHOR(S) Sue Chen 7. PERFORMING

  16. A Conceptual Model for Tropical Cyclone Formation

    NASA Astrophysics Data System (ADS)

    Wang, Z.

    2014-12-01

    The role of cumulus congestus (shallow and congestus convection) in tropical cyclone (TC) formation is examined in a high-resolution simulation of Tropical Cyclone Fay (2008). It is found that cumulus congestus plays a dominant role in moistening the lower to middle troposphere and spinning up the near-surface circulation before genesis, while deep convection plays a key role in moistening the upper troposphere and intensifying the cyclonic circulation over a deep layer. The transition from the tropical wave stage to the TC stage is marked by a substantial increase in net condensation and potential vorticity generation by deep convection in the inner wave pouch region. This study suggests that TC formation can be regarded as a two-stage process. The first stage is a gradual process of moisture preconditioning and the low-level spinup, in which cumulus congestus plays a dominant role. The second stage commences with the rapid development of deep convection in the inner pouch region after the air column is moistened sufficiently, whereupon the concentrated convective heating near the pouch center strengthens the transverse circulation and leads to the amplification of the cyclonic circulation over a deep layer. The rapid development of deep convection can be explained by the power-law increase of precipitation rate with column water vapor (CWV) above a critical value. The high CWV near the pouch center thus plays an important role in convective organization. It is also shown that cumulus congestus can effectively drive the low-level convergence and provides a direct and simple pathway for the development of the TC proto-vortex near the surface.

  17. Cyclone Center: Using Crowdsourcing to Determine Tropical Cyclone Intensity (Invited)

    NASA Astrophysics Data System (ADS)

    Hennon, C. C.; Knapp, K. R.; Schreck, C. J.; Stevens, S. E.; Kossin, J. P.

    2013-12-01

    The strength of tropical cyclones (TCs) is traditionally determined using the sustained maximum wind speed. Because TCs develop and spend most of their lifetime over tropical oceans, it is rare to directly observe a storm well enough to determine its strength accurately. The Dvorak technique was developed in the 1970s and 1980s to address this problem. By determining a number of cloud and structural characteristics from satellite images, a forecaster could now arrive at a reasonable maximum sustained wind without direct observations. However, the Dvorak technique by nature is subjective and it has been shown that trained experts frequently disagree on storm intensities. Furthermore, the application of the rules and constraints of the process has diverged with time across different forecast centers. This has led in several cases to severe disagreements in storm intensities when two or more forecast centers track the same TC. The accumulation of these differences has caused heterogeneous trends in TC intensity to arise at decadal time scales. A global reanalysis of TC intensity is required to resolve these discrepancies, but such an undertaking is unrealistic. Cyclone Center, an Internet crowd sourcing site for TCs, was created to resolve differences in TC intensities and produce a consistent 32-year (1978-2009) record of it. By using a homogeneous satellite dataset (HURSAT) and adapting the Dvorak technique into a set of three or four simple questions, laypersons perform the actions of the expert. User responses are converted into 3-hourly storm intensities. To capitalize on the crowd sourcing approach, at least 10 different users are shown the same image; this allows critical data such as cloud pattern uncertainties and storm metadata (e.g. eye size, center location, cloud pattern) to be collected. Preliminary analyses show that our citizen scientists many times outperform computer classifications in pattern matching and exhibit low bias and mean error when

  18. Emergency Department Presentations following Tropical Cyclone Yasi.

    PubMed

    Aitken, Peter; Franklin, Richard Charles; Lawlor, Jenine; Mitchell, Rob; Watt, Kerrianne; Furyk, Jeremy; Small, Niall; Lovegrove, Leone; Leggat, Peter

    2015-01-01

    Emergency departments see an increase in cases during cyclones. The aim of this study is to describe patient presentations to the Emergency Department (ED) of a tertiary level hospital (Townsville) following a tropical cyclone (Yasi). Specific areas of focus include changes in: patient demographics (age and gender), triage categories, and classification of diseases. Data were extracted from the Townsville Hospitals ED information system (EDIS) for three periods in 2009, 2010 and 2011 to coincide with formation of Cyclone Yasi (31 January 2011) to six days after Yasi crossed the coast line (8 February 2012). The analysis explored the changes in ICD10-AM 4-character classification and presented at the Chapter level. There was a marked increase in the number of patients attending the ED during Yasi, particularly those aged over 65 years with a maximum daily attendance of 372 patients on 4 Feb 2011. The most marked increases were in: Triage categories--4 and 5; and ICD categories--diseases of the skin and subcutaneous tissue (L00-L99), and factors influencing health care status (Z00-Z99). The most common diagnostic presentation across all years was injury (S00-T98). There was an increase in presentations to the ED of TTH, which peaked in the first 24-48 hours following the cyclone and returned to normal over a five-day period. The changes in presentations were mostly an amplification of normal attendance patterns with some altered areas of activity. Injury patterns are similar to overseas experience.

  19. Spiral gravity waves radiating from tropical cyclones

    NASA Astrophysics Data System (ADS)

    Nolan, David S.; Zhang, Jun A.

    2017-04-01

    Internal gravity waves are continuously generated by deep moist convection around the globe. Satellite images suggest that tropical cyclones produce short-wavelength, high-frequency waves that radiate outward, with the wave fronts wrapped into tight spirals by the large differential advection of the sheared tangential flow. This letter presents new in situ observations of such waves from two sources: flight level data from research aircraft that show radial wavelengths of 2-10 km and vertical velocity magnitudes from 0.1 to 1.0 ms-1 and surface observations from a research buoy in the Pacific that indicate the passage of gravity waves overhead as tropical cyclones pass by at distances of 100 to 300 km. Numerical simulations are used to interpret these observations and to understand the broader horizontal and vertical structures of the radiating waves. The simulations suggest a correlation between wave amplitude and cyclone intensity, which could be used to make remote estimates of peak wind speeds.

  20. Data Analysis of Tropical Cyclone Size

    NASA Astrophysics Data System (ADS)

    Tang, N. W.; Su, H.

    2012-12-01

    The geometric size of a tropical cyclone (TC) is directly related to its destructive potential. However, widely used measures for TC activity and destructive potential, such as the accumulated cyclone energy (ACE) and power dissipation index (PDI), are based on maximum wind speed, without considering storm size. Our analysis of the Automated Tropical Cyclone Forecast (ATCF), Joint Typhoon Warning Center (JWTC), and National Hurricane Center (NHC) best track data shows that storm size is positively correlated with TC intensity and translation speed globally. The revised ACE and PDI (RACE and RPDI) take into account storm size but do not have a significant effect on annual trends for TC activity and destructive potential. In the Atlantic basin (AL), TC activity and destructiveness measures bear positive correlations with HadISST September sea surface temperature in both short and long term analysis. In the Western Pacific basin (WP), the annual trends of RACE and RPDI exhibit much stronger correlations with local August SST than ACE and PDI. Both results imply a potentially strong linkage between global warming and hurricane destructiveness.

  1. Tropical cyclone intensities from satellite microwave data

    NASA Technical Reports Server (NTRS)

    Vonderhaar, T. H.; Kidder, S. Q.

    1980-01-01

    Radial profiles of mean 1000 mb to 250 mb temperature from the Nimbus 6 scanning microwave spectrometer (SCAMS) were constructed around eight intensifying tropical storms in the western Pacific. Seven storms showed distinct inward temperature gradients required for intensification; the eighth displayed no inward gradient and was decaying 24 hours later. The possibility that satellite data might be used to forecast tropical cyclone turning motion was investigated using estimates obtained from Nimbus 6 SCAMS data tapes of the mean 1000 mb to 250 mb temperature field around eleven tropical storms in 1975. Analysis of these data show that for turning storms, in all but one case, the turn was signaled 24 hours in advance by a significant temperature gradient perpendicular to the storm's path, at a distance of 9 deg to 13 deg in front of the storm. A thresholding technique was applied to the North Central U.S. during the summer to estimate precipitation frequency. except

  2. Space options for tropical cyclone hazard mitigation

    NASA Astrophysics Data System (ADS)

    Dicaire, Isabelle; Nakamura, Ryoko; Arikawa, Yoshihisa; Okada, Kazuyuki; Itahashi, Takamasa; Summerer, Leopold

    2015-02-01

    This paper investigates potential space options for mitigating the impact of tropical cyclones on cities and civilians. Ground-based techniques combined with space-based remote sensing instrumentation are presented together with space-borne concepts employing space solar power technology. Two space-borne mitigation options are considered: atmospheric warming based on microwave irradiation and laser-induced cloud seeding based on laser power transfer. Finally technology roadmaps dedicated to the space-borne options are presented, including a detailed discussion on the technological viability and technology readiness level of our proposed systems. Based on these assessments, the space-borne cyclone mitigation options presented in this paper may be established in a quarter of a century.

  3. 1995 Annual Tropical Cyclone Report

    DTIC Science & Technology

    1995-01-01

    BAILEY JASON E. ECCLES ROBERT M. GIGUERE DAVID J. CORREA , JR. JORDAN S. KELLY VINCENT L. PETRASEK JEFFREY L. WILKERSON TIMOTHY C. WILLlAMS CLARK D. WILSON...07W TY Gary 08W TY Helen 09W TS Irving 10W TS Janis lIW TD 12W STY Kent 13W TY Lois 14W TY Mark 15W TS Nina 16W TD 17W STY Oscar Individual Tropical...14W TY MARK 15W TS NINA 16W TD 17W STY OSCAR 18W TY POLLY 19W STY RYAN 20W TY SIBYL 21W TD 22W TD 23w TD 24W TY TED 25W TS VAL 26W STY WARD 27w TY

  4. Sensitivity of tropical cyclone intensity to sea surface temperature

    SciTech Connect

    Evans, J.L. )

    1993-06-01

    Increased occurrence of more intense tropical storms intruding further poleward has been foreshadowed as one of the potential consequences of global warming. This scenario is based almost entirely on the general circulation model predictions of warmer sea surface temperature (SST) with increasing levels of atmospheric CO[sub 2] and some theories of tropical cyclone intensification that support the notion of more intense systems with warmer SST. Whether storms are able to achieve this theoretically determined more intense state depends on whether the temperature of the underlying water is the dominant factor in tropical cyclone intensification. An examination of the historical data record in a number of ocean basins is used to identify the relative importance of SST in the tropical cyclone intensification process. The results reveal that SST alone is an inadequate predictor of tropical cyclone intensity. Other factors known to affect tropical cyclone frequency and intensity are discussed. 16 refs., 6 figs., 3 tabs.

  5. Ocean barrier layers' effect on tropical cyclone intensification.

    PubMed

    Balaguru, Karthik; Chang, Ping; Saravanan, R; Leung, L Ruby; Xu, Zhao; Li, Mingkui; Hsieh, Jen-Shan

    2012-09-04

    Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are "quasi-permanent" features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.

  6. Ocean Barrier Layers’ Effect on Tropical Cyclone Intensification

    SciTech Connect

    Balaguru, Karthik; Chang, P.; Saravanan, R.; Leung, Lai-Yung R.; Xu, Zhao; Li, M.; Hsieh, J.

    2012-09-04

    Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are 'quasi-permanent' features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.

  7. Tropical Cyclone Interactions Within Central American Gyres

    NASA Astrophysics Data System (ADS)

    Papin, P. P.; Bosart, L. F.; Torn, R. D.

    2014-12-01

    Central American gyres (CAGs) are broad (~1000 km diameter) low-level cyclonic circulations that organize over Central America during the tropical cyclone (TC) season. While CAGs have rarely been studied, prior work on similar circulations has been conducted on monsoon depressions (MDs) and monsoon gyres (MGs), which possess spatial scales of 1000 - 2500 km in the west Pacific basin. A key difference between MDs and MGs is related to the organization of vorticity around the low-level circulation. MDs possess a symmetrical vorticity pattern where vorticity accumulates near the circulation center over time, occasionally developing into a large TC. In contrast, MGs possess asymmetrical vorticity, organized in mesovorticies, which rotate cyclonically along the periphery of the MG circulation. Small tropical cyclones (TCs) occasionally develop from these mesovorticies. Interaction and development of TCs within CAGs are also common, as noted by a CAG identified during the 2010 PREDICT field project, which involved the interaction of TC Matthew and the development of TC Nicole within the larger CAG. This project is motivated by the lack of prior research on CAGs, as well as the complex scale interactions that occasionally occur between TCs and CAGs. This presentation focuses on the mutual interaction of vortices embedded in the larger-scale cyclonic flow comprising the CAG circulation. Case studies will be presented using a circulation framework to illustrate the relationship between different scale vorticity elements within the CAG. Some of these case studies resemble a MD-like evolution, where a large TC develops through the accumulation of symmetrical vorticity around the CAG (e.g. TC Opal 1995, TC Frances 1998). Other instances resemble a MG-like evolution, where smaller mesovorticies rotate around a common circulation center (e.g. TC Florence 1988). The circulation analysis framework aids in the diagnosis of interaction between different scale cyclonic vortices, and

  8. NASA Sees Heavy Rainfall, Hot Towers in Tropical Cyclone Nathan

    NASA Image and Video Library

    NASA-JAXA's Tropical Rainfall Measuring Mission or TRMM satellite showed that the heaviest rainfall occurring in Tropical Cyclone Nathan on March 18 at 0758 UTC (3:58 a.m. EDT) was falling at a rat...

  9. Hydration of the upper troposphere by tropical cyclones

    NASA Astrophysics Data System (ADS)

    Ray, Eric A.; Rosenlof, Karen H.

    2007-06-01

    Tropical cyclones in the Atlantic and Pacific ocean basins are found to have a significant impact on the amount of water vapor in the tropical and subtropical upper troposphere. Measurements from AIRS on Aqua and MLS on Aura are used to reveal details of the water vapor and temperature structure of the upper troposphere in the vicinity of tropical cyclones that have been unavailable from previous satellite observations. These measurements show that the most intense tropical cyclones (categories 4 and 5) increase average water vapor mixing ratios between 300 and 150 hPa in a roughly 1500 km2 area around the cyclones by 10-50% over their lifetimes. Category 3 and weaker tropical cyclones hydrate the upper troposphere on average roughly half as effectively as the most intense cyclones. The most intense cyclones also increase average water vapor in the upper troposphere by 2-10% in the entire ocean basin in which they occur. This amount of hydration of the tropical upper troposphere suggests that tropical cyclones play a role in the water vapor budget, and associated climate feedbacks, in a region much larger than the cyclone vicinity.

  10. The Environmental Influence on Tropical Cyclone Precipitation.

    NASA Astrophysics Data System (ADS)

    Rodgers, Edward B.; Baik, Jong-Jin; Pierce, Harold F.

    1994-05-01

    The intensity, spatial, and temporal changes in precipitation were examined in three North Atlantic hurricanes during 1989 (Dean, Gabrielle, and Hugo) using precipitation estimates made from Special Sensor Microwave/Imager (SSM/I) measurements. In addition, analyses from a barotropic hurricane forecast model and the European Centre for Medium-Range Weather Forecast model were used to examine the relationship between the evolution of the precipitation in these tropical cyclones and external forcing. The external forcing parameters examined were 1) mean climatological sea surface temperatures, 2) vertical wind shear, 3) environmental tropospheric water vapor flux, and 4) upper-tropospheric eddy relative angular momentum flux convergence.The analyses revealed that 1) the SSM/I precipitation estimates were able to delineate and monitor convective ring cycles similar to those observed with land-based and aircraft radar and in situ measurements; 2) tropical cyclone intensification was observed to occur when these convective rings propagated into the inner core of these systems (within 111 km of the center) and when the precipitation rates increased; 3) tropical cyclone weakening was observed to occur when these inner-core convective rings dissipated; 4) the inward propagation of the outer convective rings coincided with the dissipation of the inner convective rings when they came within 55 km of each other; 5) in regions with the combined warm sea surface temperatures (above 26°C) and low vertical wind shear (less than 5 m s1), convective rings outside the region of strong lower-tropospheric inertial stability could be initiated by strong surges of tropospheric moisture, while convective rings inside the region of strong lower-tropospheric inertial stability could be enhanced by upper-tropospheric eddy relative angular momentum flux convergence.

  11. Lessons learnt from tropical cyclone losses

    NASA Astrophysics Data System (ADS)

    Honegger, Caspar; Wüest, Marc; Zimmerli, Peter; Schoeck, Konrad

    2016-04-01

    Swiss Re has a long history in developing natural catastrophe loss models. The tropical cyclone USA and China model are examples for event-based models in their second generation. Both are based on basin-wide probabilistic track sets and calculate explicitly the losses from the sub-perils wind and storm surge in an insurance portfolio. Based on these models, we present two cases studies. China: a view on recent typhoon loss history Over the last 20 years only very few major tropical cyclones have caused severe insurance losses in the Pearl River Delta region and Shanghai, the two main exposure clusters along China's southeast coast. Several storms have made landfall in China every year but most struck areas with relatively low insured values. With this study, we make the point that typhoon landfalls in China have a strong hit-or-miss character and available insured loss experience is too short to form a representative view of risk. Historical storm tracks and a simple loss model applied to a market portfolio - all from publicly available data - are sufficient to illustrate this. An event-based probabilistic model is necessary for a reliable judgement of the typhoon risk in China. New York: current and future tropical cyclone risk In the aftermath of hurricane Sandy 2012, Swiss Re supported the City of New York in identifying ways to significantly improve the resilience to severe weather and climate change. Swiss Re provided a quantitative assessment of potential climate related risks facing the city as well as measures that could reduce those impacts.

  12. The environmental influence on tropical cyclone precipitation

    NASA Technical Reports Server (NTRS)

    Rodgers, Edward B.; Baik, Jong-Jin; Pierce, Harold F.

    1994-01-01

    The intensity, spatial, and temporal changes in precipitation were examined in three North Atlantic hurricanes during 1989 (Dean, Gabrielle, and Hugo) using precipitation estimates made from Special Sensor Microwave/Imager (SSM/I) measurements. In addition, analyses from a barotropic hurricane forecast model and the European Centre for Medium-Range Weather Forecast model were used to examine the relationship between the evolution of the precipitation in these tropical cyclones and external forcing. The external forcing parameters examined were (1) mean climatological sea surface temperatures, (2) vertical wind shear, (3) environmental tropospheric water vapor flux, and (4) upper-tropospheric eddy relative angular momentum flux convergence. The analyses revealed that (1) the SSM/I precipitation estimates were able to delineate and monitor convective ring cycles similar to those observed with land-based and aircraft radar and in situ measurements; (2) tropical cyclone intensification was observed to occur when these convective rings propagated into the inner core of these systems (within 111 km of the center) and when the precipitation rates increased; (3) tropical cyclone weakening was observed to occur when these inner-core convective rings dissipated; (4) the inward propagation of the outer convective rings coincided with the dissipation of the inner convective rings when they came within 55 km of each other; (5) in regions with the combined warm sea surface temperatures (above 26 C) and low vertical wind shear (less than 5 m/s), convective rings outside the region of strong lower-tropospheric inertial stability could be initiated by strong surges of tropospheric moisture, while convective rings inside the region of strong lower-tropospheric inertial stability could be enhanced by upper-tropospheric eddy relative angular momentum flux convergence.

  13. Incorporation of Tropical Cyclone Avoidance Into Automated Ship Scheduling

    DTIC Science & Technology

    2014-06-01

    TROPICAL CYCLONE AVOIDANCE INTO AUTOMATED SHIP SCHEDULING by Stephen W. Lantz June 2014 Thesis Advisor: Walter DeGrange Co-Advisor: Eva...COVERED Master’s Thesis 4. TITLE AND SUBTITLE INCORPORATION OF TROPICAL CYCLONE AVOIDANCE INTO AUTOMATED SHIP SCHEDULING 5. FUNDING NUMBERS 6... cyclones (TCs) frequently disrupt these plans, requiring diversions and inefficient steaming speeds. We evaluate the impact of adding anticipated TC

  14. Tropical Cyclone Glenda in the Indian Ocean

    NASA Image and Video Library

    2017-09-28

    Tropical Cyclone Glenda took a five day tour of the Southern Indian Ocean in late February, 2015. The storm formed from a low pressure system, System 90S on February 24, when maximum sustained winds reached 40 mph (64 km/h). The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true-color image of Tropical Storm Glenda on February 25 at 08:55 UTC (3:55 a.m. EST). At that time bands of thunderstorms wrapped into the low-level center of circulation. An eye was beginning to form. At 0900 UTC (4 a.m. EST) on February 25, Glenda's maximum sustained winds were near 63.2 mph (102 km/h). It was centered near 17.6 south latitude and 69.1 east longitude, about 760 miles (1,224 km) south-southwest of Diego Garcia. Glenda was moving to the west-southwest at 8 mph (13 km/h). At that time, the Joint Typhoon Warning Center expect Glenda to strengthen to near 109 mph (176 km/h) before beginning to weaken. However, strong wind shear began to affect the storm. By the afternoon of February 26 Tropical Cyclone Glenda’s winds had dropped to about 58 mph (93 km/h), and by February 28 the storm had transitioned to an extra-tropical storm. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  15. Emergency Department Presentations following Tropical Cyclone Yasi

    PubMed Central

    Aitken, Peter; Franklin, Richard Charles; Lawlor, Jenine; Mitchell, Rob; Watt, Kerrianne; Furyk, Jeremy; Small, Niall; Lovegrove, Leone; Leggat, Peter

    2015-01-01

    Introduction Emergency departments see an increase in cases during cyclones. The aim of this study is to describe patient presentations to the Emergency Department (ED) of a tertiary level hospital (Townsville) following a tropical cyclone (Yasi). Specific areas of focus include changes in: patient demographics (age and gender), triage categories, and classification of diseases. Methods Data were extracted from the Townsville Hospitals ED information system (EDIS) for three periods in 2009, 2010 and 2011 to coincide with formation of Cyclone Yasi (31 January 2011) to six days after Yasi crossed the coast line (8 February 2012). The analysis explored the changes in ICD10-AM 4-character classification and presented at the Chapter level. Results There was a marked increase in the number of patients attending the ED during Yasi, particularly those aged over 65 years with a maximum daily attendance of 372 patients on 4 Feb 2011. The most marked increases were in: Triage categories - 4 and 5; and ICD categories - diseases of the skin and subcutaneous tissue (L00-L99), and factors influencing health care status (Z00-Z99). The most common diagnostic presentation across all years was injury (S00-T98). Discussion There was an increase in presentations to the ED of TTH, which peaked in the first 24 – 48 hours following the cyclone and returned to normal over a five-day period. The changes in presentations were mostly an amplification of normal attendance patterns with some altered areas of activity. Injury patterns are similar to overseas experience. PMID:26111010

  16. Stratified coastal ocean interactions with tropical cyclones

    NASA Astrophysics Data System (ADS)

    Glenn, S. M.; Miles, T. N.; Seroka, G. N.; Xu, Y.; Forney, R. K.; Yu, F.; Roarty, H.; Schofield, O.; Kohut, J.

    2016-03-01

    Hurricane-intensity forecast improvements currently lag the progress achieved for hurricane tracks. Integrated ocean observations and simulations during hurricane Irene (2011) reveal that the wind-forced two-layer circulation of the stratified coastal ocean, and resultant shear-induced mixing, led to significant and rapid ahead-of-eye-centre cooling (at least 6 °C and up to 11 °C) over a wide swath of the continental shelf. Atmospheric simulations establish this cooling as the missing contribution required to reproduce Irene's accelerated intensity reduction. Historical buoys from 1985 to 2015 show that ahead-of-eye-centre cooling occurred beneath all 11 tropical cyclones that traversed the Mid-Atlantic Bight continental shelf during stratified summer conditions. A Yellow Sea buoy similarly revealed significant and rapid ahead-of-eye-centre cooling during Typhoon Muifa (2011). These findings establish that including realistic coastal baroclinic processes in forecasts of storm intensity and impacts will be increasingly critical to mid-latitude population centres as sea levels rise and tropical cyclone maximum intensities migrate poleward.

  17. Stratified coastal ocean interactions with tropical cyclones

    PubMed Central

    Glenn, S. M.; Miles, T. N.; Seroka, G. N.; Xu, Y.; Forney, R. K.; Yu, F.; Roarty, H.; Schofield, O.; Kohut, J.

    2016-01-01

    Hurricane-intensity forecast improvements currently lag the progress achieved for hurricane tracks. Integrated ocean observations and simulations during hurricane Irene (2011) reveal that the wind-forced two-layer circulation of the stratified coastal ocean, and resultant shear-induced mixing, led to significant and rapid ahead-of-eye-centre cooling (at least 6 °C and up to 11 °C) over a wide swath of the continental shelf. Atmospheric simulations establish this cooling as the missing contribution required to reproduce Irene's accelerated intensity reduction. Historical buoys from 1985 to 2015 show that ahead-of-eye-centre cooling occurred beneath all 11 tropical cyclones that traversed the Mid-Atlantic Bight continental shelf during stratified summer conditions. A Yellow Sea buoy similarly revealed significant and rapid ahead-of-eye-centre cooling during Typhoon Muifa (2011). These findings establish that including realistic coastal baroclinic processes in forecasts of storm intensity and impacts will be increasingly critical to mid-latitude population centres as sea levels rise and tropical cyclone maximum intensities migrate poleward. PMID:26953963

  18. Stratified coastal ocean interactions with tropical cyclones.

    PubMed

    Glenn, S M; Miles, T N; Seroka, G N; Xu, Y; Forney, R K; Yu, F; Roarty, H; Schofield, O; Kohut, J

    2016-03-08

    Hurricane-intensity forecast improvements currently lag the progress achieved for hurricane tracks. Integrated ocean observations and simulations during hurricane Irene (2011) reveal that the wind-forced two-layer circulation of the stratified coastal ocean, and resultant shear-induced mixing, led to significant and rapid ahead-of-eye-centre cooling (at least 6 °C and up to 11 °C) over a wide swath of the continental shelf. Atmospheric simulations establish this cooling as the missing contribution required to reproduce Irene's accelerated intensity reduction. Historical buoys from 1985 to 2015 show that ahead-of-eye-centre cooling occurred beneath all 11 tropical cyclones that traversed the Mid-Atlantic Bight continental shelf during stratified summer conditions. A Yellow Sea buoy similarly revealed significant and rapid ahead-of-eye-centre cooling during Typhoon Muifa (2011). These findings establish that including realistic coastal baroclinic processes in forecasts of storm intensity and impacts will be increasingly critical to mid-latitude population centres as sea levels rise and tropical cyclone maximum intensities migrate poleward.

  19. A numerical investigation of supercells in landfalling tropical cyclones

    NASA Astrophysics Data System (ADS)

    Morin, M. J.; Parker, M. D.

    2011-05-01

    Supercell thunderstorms are known to occur in the outer rainbands of tropical cyclones (TCs), and these cells are of interest because they are occasionally tornadic. A series of multi-scale quasi-idealized TC simulations are used to study the development of outer rainband supercells. Within the environment of landfalling TCs, the sea-to-land transition of the rainbands is found to locally benefit supercell development onshore due in part to (1) enhanced surface-based destabilization during the day and (2) increased surface friction slowing and backing the low-level winds. Landfall time of day is shown to have a substantial impact on the average number, strength, and lifetime of the ensemble of simulated supercells. These idealized simulations represent a first attempt at controlled hypothesis tests for supercell and tornado ingredients within the context of a highly resolved parent TC.

  20. Tropical Cyclone Structure and Intensity Change.

    NASA Astrophysics Data System (ADS)

    Nunez, Edwin

    This paper is concerned with two basic areas in the study of tropical cyclones: (a)structure and (b)genesis and intensity change. Utilizing the compositing approach, fourteen years (1961-1974) of northwest Atlantic rawinsonde soundings are analyzed to obtain the basic thermodynamic and wind fields of the hurricane. A comparison is undertaken of the basic structure of the composited west Atlantic hurricane and the west Pacific typhoon as reported by Frank (1977a, b). Similarities and differences are discussed. In order to investigate differences which lead to tropical cyclone genesis and intensification, eighteen Atlantic and Pacific data sets are also composited and divided into two groups: (a)deepening and (b)filling/steady systems. Deepening systems are found to have supergradient winds in the lower troposphere and less subgradient winds in the upper levels than filling/steady disturbances. The thermal wind equation indicates that an imbalance exists such that deepening systems have larger vertical tangential wind shear (WS) than baroclinicity. The opposite is true of filling systems. A genesis and intensification mechanism is proposed based on the adjustment of the baroclinicity to the imbalance in the vertical shear of the tangential wind. This mechanism agrees with the work of Silva Dias and Schubert (1979) and Schubert et al. (1980) which shows that in the tropics --where the Rossby radius of deformation is large--the temperature field adjusts to the wind field. It is suggested that the initial imbalance results from alterations of the disturbance's rotational part of the wind caused by the large-scale flow. Cumulus clouds and vertical mass recycling occurring in this favorable initial vertical shear are thought to maintain and increase the original imbalance. The system tries to reach a balanced state by increasing the baroclinicity (B) in order to balance the larger vertical wind shear (WS). Intensification is produced as the inner area of the disturbance

  1. Tropical Cyclone Signatures in Atmospheric Convective Available Potential Energy

    NASA Astrophysics Data System (ADS)

    Studholme, Joshua; Gulev, Sergey

    2016-04-01

    Tropical cyclones play an important role in the climate system providing transports of energy and water vapor, forcing the ocean, and also affecting mid-latitude circulation phenomena. Tropical cyclone tracks experience strong interannual variability and in addition, longer term trend-like changes in all ocean basins. Analysis of recent historical data reveal a poleward shift in the locations of tropical cyclone tracks in both the Northern and Southern Hemispheres (Kossin et al. 2014, Nature, 509, 349-352). The physical consequences of these alterations are largely unconstrained. For example, the increasing encroachment of tropical cyclone activity into the extra-tropical environment presents a novel and still poorly understood paradigm for tropical-extratropical interactions. In this respect, the role that the atmospheric convective available potential energy (CAPE) plays in the dynamics of tropical cyclones is highly interesting. The two characteristic global-scale spatial patterns in CAPE are identified using EOF analysis. The first pattern shows an abundance of CAPE in the centre of the Pacific and corresponds to the El Nino Southern Oscillation. The second one is capturing positive CAPE anomalies in the oceanic tropics and negative anomalies over equatorial Africa. Associated with these buoyancy patterns, alterations in tropical cyclone activity occur in all basins forming both zonal and meridional patterns. Atmospheric buoyancy is the trigger for deep convection, and subsequently cyclone genesis. This is the mechanism of impact upon location at the start of cyclone tracks. It is found to have less impact upon where cyclones subsequently move, whether or not they undergo extratropical transition and when and where they experience lysis. It is shown that CAPE plays a critical role in the general circulation in the tropics which in turn is the larger steering context for embedded systems within the Walker and Hadley cells. So this lack of `latter life' impact

  2. Ocean barrier layers’ effect on tropical cyclone intensification

    PubMed Central

    Balaguru, Karthik; Chang, Ping; Saravanan, R.; Leung, L. Ruby; Xu, Zhao; Li, Mingkui; Hsieh, Jen-Shan

    2012-01-01

    Improving a tropical cyclone’s forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone’s path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are “quasi-permanent” features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity. PMID:22891298

  3. Projecting global tropical cyclone economic damages with validation of tropical cyclone economic damage model

    NASA Astrophysics Data System (ADS)

    Iseri, Y.; Iwasaki, A.; Miyazaki, C.; Kanae, S.

    2014-12-01

    Tropical cyclones (TCs) sometimes cause serious damages to human society and thus possible changes of TC properties in the future have been concerned. In fact, the Fifth Assessment Report (AR5) by IPCC (Intergovernmental Panel on Climate Change) mentions likely increasing in intensity and rain rate of TCs. In addition, future change of socioeconomic condition (e.g. population growth) might worsen TC impacts in the future. Thereby, in this study, we developed regression models to estimate economic damages by TCs (hereafter TC damage model), and employed those models to project TC economic damages under several future climate and socioeconomic scenarios. We developed the TC damage models for each of 4 regions; western North Pacific, North American, North Indian, and Southern Hemisphere. The inputs for TC damage model are tropical cyclone central pressure, populations in the area exposed by tropical cyclone wind, and GDP (Gross Domestic Product) per capita. The TC damage models we firstly developed tended to overestimate very low damages and also underestimate very high damages. Thereby we modified structure of TC damage models to improve model performance, and then executed extensive validation of the model. The modified model presented better performance in estimating very low and high TC damages. After the modification and validation of the model, we determined the structure of TC damage models and projected TC economic damages. The result indicated increase in TC economic damage in global scale, while TC economic damage against world GDP would decrease in the future, which result is consistent with previous study.

  4. Precipitation Contribution of Tropical Cyclone in the Caribbean

    NASA Astrophysics Data System (ADS)

    WANG, Y.

    2013-12-01

    Heavy rainfall from tropical cyclones (TC) can be destructive. Past studies have examined variations in global TC rainfall. Given the complexity of tropical cyclones, further studies of TC precipitation are needed at the sub-basin scale. The Caribbean is vulnerable to the tropical cyclones and the related extreme precipitation. This study will evaluate inter-annual, seasonal and monthly variations in tropical cyclone precipitation in the Caribbean, detect trends and develop a TC precipitation climatology. Precipitation data from Tropical Rainfall Measuring Mission (TRMM) 3B42 will be used to evaluate the spatial and temporal variations in TC precipitation. Then a comparative analysis between the rainfall from gauges and satellites will be performed. TC information derived from the National Hurricane Center will also be used to identify the influence of TC intensity and frequency on TC precipitation. The high spatial and temporal resolution used in this research will help to assess TC precipitation at a more local scale.

  5. Global tropical cyclone activity to decrease with climate change

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-01-01

    Given its strong dependence on sea surface temperatures and atmospheric conditions, tropical cyclone activity is expected to be strongly affected by climate change. With observational records suggesting that tropical North Atlantic hurricane activity has increased in recent decades, some scientists have suggested that global tropical cyclone activity will increase as the planet warms. Using an ensemble atmosphere general circulation model, however, Sugi and Yoshimura found that global tropical cyclone activity has undergone a long-term decline from 1872 to the present—a trend they found should continue throughout the coming century. They found that the rate of global tropical cyclone activity decreased by 12.4 hurricanes per century—8.7 fewer hurricanes per century in the Northern Hemisphere and 3.7 fewer in the Southern Hemisphere.

  6. Coastal flooding by tropical cyclones and sea-level rise.

    PubMed

    Woodruff, Jonathan D; Irish, Jennifer L; Camargo, Suzana J

    2013-12-05

    The future impacts of climate change on landfalling tropical cyclones are unclear. Regardless of this uncertainty, flooding by tropical cyclones will increase as a result of accelerated sea-level rise. Under similar rates of rapid sea-level rise during the early Holocene epoch most low-lying sedimentary coastlines were generally much less resilient to storm impacts. Society must learn to live with a rapidly evolving shoreline that is increasingly prone to flooding from tropical cyclones. These impacts can be mitigated partly with adaptive strategies, which include careful stewardship of sediments and reductions in human-induced land subsidence.

  7. Saturn's Polar Cyclones: Idealized 2-layer Experiments of Vorticity Mixing

    NASA Astrophysics Data System (ADS)

    O'Neill, M. E.; Emanuel, K.; Flierl, G.

    2013-12-01

    The Cassini mission has provided unprecedented high-resolution observations of Saturn's atmosphere. Among many discoveries, a massive warm-core cyclonic vortex has been observed on each pole. The South Polar Vortex (SPV), specifically, has the highest measured temperatures on Saturn, a double eyewall, deep eye and a rapid cyclonic jet with the second highest windspeeds observed on the planet. However, in part because Saturn lacks the thermal disequilibrium mechanism understood to be the energy source for tropical cyclones, scientists have yet to explain the storms' dynamics and energy source. Interestingly, numerous small, vortical (in the case of at least the SPV), and potentially convective systems are embedded within the large-scale flow of both polar vortices. We explore one potential mechanism of vortex maintenance: up-scale, poleward vorticity flux due to vortical hot towers (VHTs). Large GCMs cannot yet resolve local deep convection in the weather layer. Using a two-layer shallow water model on a polar β-plane, we represent deep convection with heton-like vortex pairs and allow them to move freely. We present results from a forced-dissipative system where the forcing is only at the convective scale, and show the effect of this 'convection' on a polar cyclone.

  8. Tropical cyclone recurvature: An intrinsic property?

    NASA Astrophysics Data System (ADS)

    Chan, Kelvin T. F.; Chan, Johnny C. L.

    2016-08-01

    The typical track of a tropical cyclone (TC) in the Northern Hemisphere is an initial northwestward movement followed by an eventual turning toward the east. Such turning is referred to as recurvature and often explained by the change of the environmental flow that steers the TC. Here we show that even in the absence of background flow, a TC initiated at a high enough latitude can recurve itself. Differential horizontal advection of the planetary vorticity by the TC circulation at different vertical levels leads to the development of vertical wind shear, upper tropospheric anticyclone, and asymmetric distribution of convection. The flow associated with the upper tropospheric anticyclone on the equatorward side of the TC and the diabatic heating associated with the asymmetric convection combine to cause the TC to recurve. Such knowledge, an intrinsic recurvature property of the TC is important in forecasting the TC track when the environmental flow is weak.

  9. Targeted ocean sampling guidance for tropical cyclones

    NASA Astrophysics Data System (ADS)

    Chen, Sue; Cummings, James A.; Schmidt, Jerome M.; Sanabia, Elizabeth R.; Jayne, Steven R.

    2017-05-01

    A 3-D variational ocean data assimilation adjoint approach is used to examine the impact of ocean observations on coupled tropical cyclone (TC) model forecast error for three recent hurricanes: Isaac (2012), Hilda (2015), and Matthew (2016). In addition, this methodology is applied to develop an innovative ocean observation targeting tool validated using TC model simulations that assimilate ocean temperature observed by Airborne eXpendable Bathy Thermographs and Air-Launched Autonomous Micro-Observer floats. Comparison between the simulated targeted and real observation data assimilation impacts reveals a positive maximum mean linear correlation of 0.53 at 400-500 m, which implies some skill in the targeting application. Targeted ocean observation regions from these three hurricanes, however, show that the largest positive impacts in reducing the TC model forecast errors are sensitive to the initial prestorm ocean conditions such as the location and magnitude of preexisting ocean eddies, storm-induced ocean cold wake, and model track errors.

  10. The Effect of Vertical Wind Shear on Tropical Cyclone Movement

    DTIC Science & Technology

    1988-01-01

    by Sanders and Burpee (1968), is a one-layer model which uses the barotropic vorticity equation to forecast the vertically averaged vorticity field...of factors which could modify cyclone movement. With the advent of numerical predication methods, it became possible to test these concepts. Numerical...conditions to test the cyclone features, are also presented. Chapter 3 investigates the effects of the physical processes on tropical cyclone movement by

  11. Putting to rest WISHE-ful misconceptions for tropical cyclone intensification

    NASA Astrophysics Data System (ADS)

    Montomery, Michael T.; Persing, John; Smith, Roger K.

    2015-03-01

    The purpose of this article is twofold. The first is to point out and correct several misconceptions about the putative WISHE mechanism of tropical cyclone intensification that currently are being taught to atmospheric science students, to tropical weather forecasters, and to laypeople who seek to understand how tropical cyclones intensify. The mechanism relates to the simplest problem of an initial cyclonic vortex in a quiescent environment. This first part is important because the credibility of tropical cyclone science depends inter alia on being able to articulate a clear and consistent picture of the hypothesized intensification process and its dependencies on key flow parameters. The credibility depends also on being able to test the hypothesized mechanisms using observations, numerical models, or theoretical analyses. The second purpose of the paper is to carry out new numerical experiments using a state-of-the-art numerical model to test a recent hypothesis invoking the WISHE feedback mechanism during the rapid intensification phase of a tropical cyclone. The results obtained herein, in conjunction with prior work, do not support this recent hypothesis and refute the view that the WISHE intensification mechanism is the essential mechanism of tropical cyclone intensification in the idealized problem that historically has been used to underpin the paradigm. This second objective is important because it presents a simple way of testing the hypothesized intensification mechanism and shows that the mechanism is neither essential nor the dominant mode of intensification for the prototype intensification problem. In view of the operational, societal, and scientific interest in the physics of tropical cyclone intensification, we believe this paper will be of broad interest to the atmospheric science community and the findings should be useful in both the classroom setting and frontier research.

  12. Impacts of tropical cyclones on Fiji and Samoa

    NASA Astrophysics Data System (ADS)

    Kuleshov, Yuriy; Prakash, Bipendra; Atalifo, Terry; Waqaicelua, Alipate; Seuseu, Sunny; Ausetalia Titimaea, Mulipola

    2013-04-01

    Weather and climate hazards have significant impacts on Pacific Island Countries. Costs of hazards such as tropical cyclones can be astronomical making enormous negative economic impacts on developing countries. We highlight examples of extreme weather events which have occurred in Fiji and Samoa in the last few decades and have caused major economic and social disruption in the countries. Destructive winds and torrential rain associated with tropical cyclones can bring the most damaging weather conditions to the region causing economic and social hardship, affecting agricultural productivity, infrastructure and economic development which can persist for many years after the initial impact. Analysing historical data, we describe the impacts of tropical cyclones Bebe and Kina on Fiji. Cyclone Bebe (October 1972) affected the whole Fiji especially the Yasawa Islands, Viti Levu and Kadavu where hurricane force winds have been recorded. Nineteen deaths were reported and damage costs caused by cyclone Bebe were estimated as exceeding F20 million (F 1972). Tropical cyclone Kina passed between Fiji's two main islands of Viti Levu and Vanua Levu, and directly over Levuka on the night of 2 January 1993 with hurricane force winds causing extensive damage. Twenty three deaths have been reported making Kina one of the deadliest hurricanes in Fiji's recent history. Severe flooding on Viti Levu, combined with high tide and heavy seas led to destruction of the Sigatoka and Ba bridges, as well as almost complete loss of crops in Sigatoka and Navua deltas. Overall, damage caused by cyclone Kina was estimated as F170 million. In Samoa, we describe devastation to the country caused by tropical cyclones Ofa (February 1990) and Val (December 1991) which were considered to be the worst cyclones to affect the Samoan islands since the 1889 Apia cyclone. In Samoa, seven people were killed due to cyclone Ofa, thousands of people were left homeless and entire villages were destroyed. Damage

  13. TRMM Sees Rainfall Totals from Tropical Cyclone Guito

    NASA Image and Video Library

    This animation of rainfall gathered from February 11-19, 2014 by NASA's TRMM satellite revealed that Tropical Cyclone Guito produced as much as 16.9 inches/430 mm of rainfall in the center of the M...

  14. GPM Sees Heavy Rain in Tropical Cyclone Yvette

    NASA Image and Video Library

    On Dec. 19, the GPM core satellite found Tropical Cyclone 02S was dropping rain at a rate of over 127 mm (5 inches) per hour in this area of intense convective showers where cloud tops reached alti...

  15. GPM Satellite Flyby of Tropical Cyclone 03S

    NASA Image and Video Library

    On January 25 at 6:51 p.m. EST (2351 UTC) the GPM satellite found rainfall rates in some of the bands of thunderstorms around the developing tropical cyclone were falling at a rate of almost 83 mm ...

  16. Tropical Cyclone Mahasen Rain Moving Into Bay Of Bengal

    NASA Image and Video Library

    This animated TRMM Multisatellite Precipitation Analysis shows the rainfall that occurred with Tropical Cyclone Mahasen during the week of May 6 through 13, 2013 as it moved through the Bay of Beng...

  17. NASA Sees Heavy Rain in Arabian Sea Tropical Cyclone

    NASA Image and Video Library

    On June 29, GPM showed Tropical Cyclone 02A had a few powerful convective thunderstorms southwest of the center of circulation were dropping rain at the extreme rate of over 209 mm (8.2 inches) per...

  18. GPM Satellite Sees Heavy Rainfall in Tropical Cyclone Carlos

    NASA Image and Video Library

    The GPM core observatory satellite flew above tropical cyclone Carlos on February 7, 2017 at 1056 UTC and measured a few downpours in the bands west of the Carlos' center of circulation dropping ra...

  19. Tropical Cyclone Gonu Viewed by CloudSat

    NASA Image and Video Library

    2007-06-07

    The image of Tropical Cyclone Gonu in the upper panel was taken by the Moderate Resolution Imaging Spectroradiometer MODIS instrument on NASA Aqua satellite on June 5, 2007, at approximately 20:20 UTC.

  20. Rainfall Totals from the Tropical Cyclones Passing Over Philippines

    NASA Image and Video Library

    Rainfall totals from the TRMM satellite of all tropical cyclones that passed through the Philippines from January through November 11, 2013. Red indicated areas where rainfall totals were greater t...

  1. A simple method for simulating wind profiles in the boundary layer of tropical cyclones

    SciTech Connect

    Bryan, George H.; Worsnop, Rochelle P.; Lundquist, Julie K.; Zhang, Jun A.

    2016-11-01

    A method to simulate characteristics of wind speed in the boundary layer of tropical cyclones in an idealized manner is developed and evaluated. The method can be used in a single-column modelling set-up with a planetary boundary-layer parametrization, or within large-eddy simulations (LES). The key step is to include terms in the horizontal velocity equations representing advection and centrifugal acceleration in tropical cyclones that occurs on scales larger than the domain size. Compared to other recently developed methods, which require two input parameters (a reference wind speed, and radius from the centre of a tropical cyclone) this new method also requires a third input parameter: the radial gradient of reference wind speed. With the new method, simulated wind profiles are similar to composite profiles from dropsonde observations; in contrast, a classic Ekman-type method tends to overpredict inflow-layer depth and magnitude, and two recently developed methods for tropical cyclone environments tend to overpredict near-surface wind speed. When used in LES, the new technique produces vertical profiles of total turbulent stress and estimated eddy viscosity that are similar to values determined from low-level aircraft flights in tropical cyclones. Lastly, temporal spectra from LES produce an inertial subrange for frequencies ≳0.1 Hz, but only when the horizontal grid spacing ≲20 m.

  2. A simple method for simulating wind profiles in the boundary layer of tropical cyclones

    DOE PAGES

    Bryan, George H.; Worsnop, Rochelle P.; Lundquist, Julie K.; ...

    2016-11-01

    A method to simulate characteristics of wind speed in the boundary layer of tropical cyclones in an idealized manner is developed and evaluated. The method can be used in a single-column modelling set-up with a planetary boundary-layer parametrization, or within large-eddy simulations (LES). The key step is to include terms in the horizontal velocity equations representing advection and centrifugal acceleration in tropical cyclones that occurs on scales larger than the domain size. Compared to other recently developed methods, which require two input parameters (a reference wind speed, and radius from the centre of a tropical cyclone) this new method alsomore » requires a third input parameter: the radial gradient of reference wind speed. With the new method, simulated wind profiles are similar to composite profiles from dropsonde observations; in contrast, a classic Ekman-type method tends to overpredict inflow-layer depth and magnitude, and two recently developed methods for tropical cyclone environments tend to overpredict near-surface wind speed. When used in LES, the new technique produces vertical profiles of total turbulent stress and estimated eddy viscosity that are similar to values determined from low-level aircraft flights in tropical cyclones. Lastly, temporal spectra from LES produce an inertial subrange for frequencies ≳0.1 Hz, but only when the horizontal grid spacing ≲20 m.« less

  3. A Simple Method for Simulating Wind Profiles in the Boundary Layer of Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Bryan, George H.; Worsnop, Rochelle P.; Lundquist, Julie K.; Zhang, Jun A.

    2017-03-01

    A method to simulate characteristics of wind speed in the boundary layer of tropical cyclones in an idealized manner is developed and evaluated. The method can be used in a single-column modelling set-up with a planetary boundary-layer parametrization, or within large-eddy simulations (LES). The key step is to include terms in the horizontal velocity equations representing advection and centrifugal acceleration in tropical cyclones that occurs on scales larger than the domain size. Compared to other recently developed methods, which require two input parameters (a reference wind speed, and radius from the centre of a tropical cyclone) this new method also requires a third input parameter: the radial gradient of reference wind speed. With the new method, simulated wind profiles are similar to composite profiles from dropsonde observations; in contrast, a classic Ekman-type method tends to overpredict inflow-layer depth and magnitude, and two recently developed methods for tropical cyclone environments tend to overpredict near-surface wind speed. When used in LES, the new technique produces vertical profiles of total turbulent stress and estimated eddy viscosity that are similar to values determined from low-level aircraft flights in tropical cyclones. Temporal spectra from LES produce an inertial subrange for frequencies ≳ 0.1 Hz, but only when the horizontal grid spacing ≲ 20 m.

  4. A Simple Method for Simulating Wind Profiles in the Boundary Layer of Tropical Cyclones

    SciTech Connect

    Bryan, George H.; Worsnop, Rochelle P.; Lundquist, Julie K.; Zhang, Jun A.

    2016-11-01

    A method to simulate characteristics of wind speed in the boundary layer of tropical cyclones in an idealized manner is developed and evaluated. The method can be used in a single-column modelling set-up with a planetary boundary-layer parametrization, or within large-eddy simulations (LES). The key step is to include terms in the horizontal velocity equations representing advection and centrifugal acceleration in tropical cyclones that occurs on scales larger than the domain size. Compared to other recently developed methods, which require two input parameters (a reference wind speed, and radius from the centre of a tropical cyclone) this new method also requires a third input parameter: the radial gradient of reference wind speed. With the new method, simulated wind profiles are similar to composite profiles from dropsonde observations; in contrast, a classic Ekman-type method tends to overpredict inflow-layer depth and magnitude, and two recently developed methods for tropical cyclone environments tend to overpredict near-surface wind speed. When used in LES, the new technique produces vertical profiles of total turbulent stress and estimated eddy viscosity that are similar to values determined from low-level aircraft flights in tropical cyclones. Temporal spectra from LES produce an inertial subrange for frequencies >/~0.1 Hz, but only when the horizontal grid spacing >/~20 m.

  5. The increasing intensity of the strongest tropical cyclones.

    PubMed

    Elsner, James B; Kossin, James P; Jagger, Thomas H

    2008-09-04

    Atlantic tropical cyclones are getting stronger on average, with a 30-year trend that has been related to an increase in ocean temperatures over the Atlantic Ocean and elsewhere. Over the rest of the tropics, however, possible trends in tropical cyclone intensity are less obvious, owing to the unreliability and incompleteness of the observational record and to a restricted focus, in previous trend analyses, on changes in average intensity. Here we overcome these two limitations by examining trends in the upper quantiles of per-cyclone maximum wind speeds (that is, the maximum intensities that cyclones achieve during their lifetimes), estimated from homogeneous data derived from an archive of satellite records. We find significant upward trends for wind speed quantiles above the 70th percentile, with trends as high as 0.3 +/- 0.09 m s(-1) yr(-1) (s.e.) for the strongest cyclones. We note separate upward trends in the estimated lifetime-maximum wind speeds of the very strongest tropical cyclones (99th percentile) over each ocean basin, with the largest increase at this quantile occurring over the North Atlantic, although not all basins show statistically significant increases. Our results are qualitatively consistent with the hypothesis that as the seas warm, the ocean has more energy to convert to tropical cyclone wind.

  6. The contribution of tropical cyclones to rainfall in Mexico

    NASA Astrophysics Data System (ADS)

    Agustín Breña-Naranjo, J.; Pedrozo-Acuña, Adrián; Pozos-Estrada, Oscar; Jiménez-López, Salma A.; López-López, Marco R.

    Investigating the contribution of tropical cyclones to the terrestrial water cycle can help quantify the benefits and hazards caused by the rainfall generated from this type of hydro-meteorological event. Rainfall induced by tropical cyclones can enhance both flood risk and groundwater recharge, and it is therefore important to characterise its minimum, mean and maximum contributions to a region or country's water balance. This work evaluates the rainfall contribution of tropical depressions, storms and hurricanes across Mexico from 1998 to 2013 using the satellite-derived precipitation dataset TMPA 3B42. Additionally, the sensitivity of rainfall to other datasets was assessed: the national rain gauge observation network, real-time satellite rainfall and a merged product that combines rain gauges with non-calibrated space-borne rainfall measurements. The lower Baja California peninsula had the highest contribution from cyclonic rainfall in relative terms (∼40% of its total annual rainfall), whereas the contributions in the rest of the country showed a low-to-medium dependence on tropical cyclones, with mean values ranging from 0% to 20%. In quantitative terms, southern regions of Mexico can receive more than 2400 mm of cyclonic rainfall during years with significant TC activity. Moreover, (a) the number of tropical cyclones impacting Mexico has been significantly increasing since 1998, but cyclonic contributions in relative and quantitative terms have not been increasing, and (b) wind speed and rainfall intensity during cyclones are not highly correlated. Future work should evaluate the impacts of such contributions on surface and groundwater hydrological processes and connect the knowledge gaps between the magnitude of tropical cyclones, flood hazards, and economic losses.

  7. Tropical cyclone intensity change. A quantitative forecasting scheme

    NASA Technical Reports Server (NTRS)

    Dropco, K. M.; Gray, W. M.

    1981-01-01

    One to two day future tropical cyclone intensity change from both a composite and an individual case point-of-view are discussed. Tropical cyclones occurring in the Gulf of Mexico during the period 1957-1977 form the primary data source. Weather charts of the NW Atlantic were initially examined, but few differences were found between intensifying and non-intensifying cyclones. A rawinsonde composite analysis detected composite differences in the 200 mb height fields, the 850 mb temperature fields, the 200 mb zonal wind and the vertical shears of the zonal wind. The individual cyclones which make up the composite study were then separately examined using this composite case knowledge. Similar parameter differences were found in a majority of individual cases. A cyclone intensity change forecast scheme was tested against independent storm cases. Correct predictions of intensification or non-intensification could be made approximately 75% of the time.

  8. Damaging sediment density flows triggered by tropical cyclones

    NASA Astrophysics Data System (ADS)

    Pope, Ed L.; Talling, Peter J.; Carter, Lionel; Clare, Michael A.; Hunt, James E.

    2017-01-01

    The global network of subsea fibre-optic cables plays a critical role in the world economy and is considered as strategic infrastructure for many nations. Sediment density flows have caused significant disruption to this network in the recent past. These cable breaks represent the only means to actively monitor such flows over large oceanic regions. Here, we use a global cable break database to analyse tropical cyclone triggering of sediment density flows worldwide over 25 yrs. Cable breaking sediment density flows are triggered in nearly all areas exposed to tropical cyclones but most occur in the NW Pacific. They are triggered by one of three sets of mechanisms. Tropical cyclones directly trigger flows, synchronous to their passage, as a consequence of storm waves, currents and surges. Cyclones also trigger flows indirectly, with near-synchronous timing to their passage, as a consequence of peak flood discharges. Last, cyclones trigger flows after a delay of days as a consequence of the failure of large volumes of rapidly deposited sediment. No clear relationship emerges between tropical cyclone activity (i.e. track, frequency and intensity) and the number of sediment density flows triggered. This is a consequence of the short period of observation. However, expansion of the cable network and predicted changes to cyclone activity in specific regions increases the likelihood of increasing numbers of damaging flows.

  9. The Intensification of Sheared Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Nguyen, Leon Trungduong

    Environmental vertical wind shear has been shown to have a generally detrimental impact on tropical cyclone (TC) intensity change. However, many cases of rapidly intensifying (RI) sheared TCs have been observed, and TCs in moderate (5-10 m s-1) shear often have the largest intensity forecast errors. Thus, advancing the understanding of TC-shear interactions is vital to improving TC intensity forecasts, which have not seen much improvement over the past few decades. This dissertation employs both observational and high-resolution numerical modeling approaches to investigate how some TCs are able to resist shear and intensify. The rapid intensification of Hurricane Irene (1999) was studied using observations, while the short-term RI of Tropical Storm Gabrielle (2001) was simulated using the Weather Research and Forecast (WRF) model run at 1-km horizontal resolution. Both storms exhibited a downshear-left vortex tilt and a marked azimuthal wavenumber-1 convective asymmetry. However, the azimuthally averaged diabatic heating also increased, suggesting that TC intensity may be more sensitive to the azimuthally averaged component of diabatic heating rather than the asymmetric component. Furthermore, this increase occurred within the radius of maximum winds (RMW), a region theorized to favor rapid spinup of the vortex. A key difference between the Irene and Gabrielle cases was that the latter underwent a downshear reformation. The circulation associated with an intense mesovortex and other localized cyclonic vorticity anomalies comprised a developing "inner vortex" on the downshear-left (downtilt) periphery of the broader parent vortex. This inner vortex was nearly upright within a parent vortex that was tilted significantly with height. The inner vortex became the dominant vortex of the system, advecting and absorbing the broad, tilted parent vortex. A method was developed for diagnosing vortex tilt in the simulation. The reduction of TC vortex tilt from 65 km to 20 km

  10. Extra-tropical Cyclones and Windstorms in Seasonal Forecasts

    NASA Astrophysics Data System (ADS)

    Leckebusch, Gregor C.; Befort, Daniel J.; Weisheimer, Antje; Knight, Jeff; Thornton, Hazel; Roberts, Julia; Hermanson, Leon

    2015-04-01

    Severe damages and large insured losses over Europe related to natural phenomena are mostly caused by extra-tropical cyclones and their related windstorm fields. Thus, an adequate representation of these events in seasonal prediction systems and reliable forecasts up to a season in advance would be of high value for society and economy. In this study, state-of-the-art seasonal forecast prediction systems are analysed (ECMWF, UK Met Office) regarding the general climatological representation and the seasonal prediction of extra-tropical cyclones and windstorms during the core winter season (DJF) with a lead time of up to four months. Two different algorithms are used to identify cyclones and windstorm events in these datasets. Firstly, we apply a cyclone identification and tracking algorithm based on the Laplacian of MSLP and secondly, we use an objective wind field tracking algorithm to identify and track continuous areas of extreme high wind speeds (cf. Leckebusch et al., 2008), which can be related to extra-tropical winter cyclones. Thus, for the first time, we can analyse the forecast of severe wind events near to the surface caused by extra-tropical cyclones. First results suggest a successful validation of the spatial climatological distributions of wind storm and cyclone occurrence in the seasonal forecast systems in comparison with reanalysis data (ECMWF-ERA40 & ERAInterim) in general. However, large biases are found for some areas. The skill of the seasonal forecast systems in simulating the year-to-year variability of the frequency of severe windstorm events and cyclones is investigated using the ranked probability skill score. Positive skill is found over large parts of the Northern Hemisphere as well as for the most intense extra-tropical cyclones and its related wind fields.

  11. Tropical cyclone motion and recurvature in TCM-90. Master's thesis

    SciTech Connect

    Fitzpatrick, M.E.

    1992-01-01

    Rawinsonde and satellite data collected during the Tropical Cyclone Motion (TCM90) experiment, which was conducted during the summer of 1990 in the Western North pacific, is used to examine tropical cyclone steering motion and recurvature. TCM-90 composite results are compared with those found in a composite study using twenty-one years (1957-77) of Western North Pacific rawinsonde data during the same August-September period and also for all months during this same 21-year period. Both data sets indicate that the composite deep-layer-mean (850-300 mb) winds 5-7 deg from the cyclone center provide an important component of the steering flow for tropical cyclones. However, despite the rawinsonde data enhancements of the TCM-90 experiment, data limitations prevented an accurate observation of steering flow conditions at individual time periods or for the average of only 5-10 time periods when composited together.

  12. The View from the Top: CALIOP Ice Water Content in the Uppermost Layer of Tropical Cyclones

    NASA Technical Reports Server (NTRS)

    Avery, Melody A.; Deng, Min; Garnier, Anne; Heymsfield, Andrew; Pelon, Jacques; Powell, Kathleen A.; Trepte, Charles R.; Vaughan, Mark A.; Winker, David M.; Young, Stuart

    2012-01-01

    NASA's CALIPSO satellite carries both the Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP) and the Imaging Infrared Radiometer (IIR). The lidar is ideally suited to viewing the very top of tropical cyclones, and the IIR provides critical optical and microphysical information. The lidar and the IIR data work together to understand storm clouds since they are perfectly co-located, and big tropical cyclones provide an excellent complex target for comparing the observations. There is a lot of information from these case studies for understanding both the observations and the tropical cyclones, and we are just beginning to scratch the surface of what can be learned. Many tropical cyclone cloud particle measurements are focused on the middle and lower regions of storms, but characterization of cyclone interaction with the lowermost stratosphere at the upper storm boundary may be important for determining the total momentum and moisture transport budget, and perhaps for predicting storm intensity as well. A surprising amount of cloud ice is to be found at the very top of these big storms.

  13. Cloud Condensation Nuclei Measurements in Tropical Cyclones

    NASA Technical Reports Server (NTRS)

    Hudson, J. G.; Simpson, J.

    2002-01-01

    The first measurements of cloud condensation nuclei (CCN) within and around tropical cyclones were made with the Desert Research Institute (DRI) CCN spectrometer (Hudson 1909) from a NOAA P-3 Hurricane Hunter aircraft throughout the 2001 season. Two penetrations of the closed eye of Hurricane Erin off the northeast US coast on Sept. 10 showed concentrations consistently well in excess of 1000 per cubic cm at approximately 1.4% supersaturation. Simultaneous condensation nuclei (CN--total particle) concentrations were consistently well in excess of 2000 per cubic cm throughout these closed eye penetrations. These within eye measurements at 4 km altitude for exceeded CCN and CN measurements just outside of the storm at similar altitudes--300 and 600 per cubic cm respectively. These CCN and CN concentrations within this closed eye were far above concentrations in maritime air masses; they are characteristic of continental or polluted air masses. Although there was a possibility that Saharan duct may have gotten into this storm these sub tenth micrometer particles are much too small and much too numerous to be dust. Such high concentrations may have originated from European air pollution, which may have been transported by similar airflow patterns to those that carry Saharan dust across the Atlantic. These high concentrations may be a manifestation of descending air that brings higher concentrations that are often characteristic of the upper troposphere (Clarke and Kapustin 2002). Later in the month measurements in Humberto showed highly variable CCN and CN concentrations that ranged from lots than 5 per cubic cm to more than 1000 per Cubic cm over km scale distances within and around the open eye of this tropical storm/hurricane. These very low concentrations suggest strong cloud scavenging.

  14. Cloud Condensation Nuclei Measurements in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Hudson, J. G.; Simpson, J.

    2002-05-01

    The first measurements of cloud condensation nuclei (CCN) within and around tropical cyclones were made with the Desert Research Institute (DRI) CCN spectrometer (Hudson 1989) from a NOAA P-3 Hurricane Hunter aircraft throughout the 2001 season. Two penetrations of the closed eye of Hurricane Erin off the northeast US coast on Sept. 10 showed concentrations consistently well in excess of 1000 per cubic cm at approximately 1.4% supersaturation. Simultaneous condensation nuclei (CN--total particle) concentrations were consistently well in excess of 2000 per cubic cm throughout these closed eye penetrations. These within eye measurements at 4 km altitude far exceeded CCN and CN measurements just outside of the storm at similar altitudes--300 and 600 per cubic cm respectively. These CCN and CN concentrations within this closed eye were far above concentrations in maritime air masses; they are characteristic of continental or polluted air masses. Although there was a possibility that Saharan dust may have gotten into this storm these sub tenth micrometer particles are much too small and much too numerous to be dust. Such high concentrations may have originated from European air pollution, which may have been transported by similar airflow patterns to those that carry Saharan dust across the Atlantic. These high concentrations may be a manifestation of descending air that brings higher concentrations that are often characteristic of the upper troposphere (Clarke and Kapustin 2002). Later in the month measurements in Humberto showed highly variable CCN and CN concentrations that ranged from less than 5 per cubic cm to more than 1000 per cubic cm over km scale distances within and around the open eye of this tropical storm/hurricane. These very low concentrations suggest strong cloud scavenging. Clarke, A.D. and V.N. Kapustin, J. Atmos. Sci., 59, 363-382, 2002. Hudson, J.G., J. Atmos. & Ocean. Tech., 6, 1055-1065, 1989.

  15. Cloud Condensation Nuclei Measurements in Tropical Cyclones

    NASA Technical Reports Server (NTRS)

    Hudson, J. G.; Simpson, J.

    2002-01-01

    The first measurements of cloud condensation nuclei (CCN) within and around tropical cyclones were made with the Desert Research Institute (DRI) CCN spectrometer (Hudson 1909) from a NOAA P-3 Hurricane Hunter aircraft throughout the 2001 season. Two penetrations of the closed eye of Hurricane Erin off the northeast US coast on Sept. 10 showed concentrations consistently well in excess of 1000 per cubic cm at approximately 1.4% supersaturation. Simultaneous condensation nuclei (CN--total particle) concentrations were consistently well in excess of 2000 per cubic cm throughout these closed eye penetrations. These within eye measurements at 4 km altitude for exceeded CCN and CN measurements just outside of the storm at similar altitudes--300 and 600 per cubic cm respectively. These CCN and CN concentrations within this closed eye were far above concentrations in maritime air masses; they are characteristic of continental or polluted air masses. Although there was a possibility that Saharan duct may have gotten into this storm these sub tenth micrometer particles are much too small and much too numerous to be dust. Such high concentrations may have originated from European air pollution, which may have been transported by similar airflow patterns to those that carry Saharan dust across the Atlantic. These high concentrations may be a manifestation of descending air that brings higher concentrations that are often characteristic of the upper troposphere (Clarke and Kapustin 2002). Later in the month measurements in Humberto showed highly variable CCN and CN concentrations that ranged from lots than 5 per cubic cm to more than 1000 per Cubic cm over km scale distances within and around the open eye of this tropical storm/hurricane. These very low concentrations suggest strong cloud scavenging.

  16. Tropical cyclones in reanalysis data sets

    NASA Astrophysics Data System (ADS)

    Murakami, Hiroyuki

    2014-03-01

    This study evaluates and compares tropical cyclones (TCs) in state-of-the-art reanalysis data sets including the following: the Japanese 55-year Reanalysis (JRA-55), Japanese 25-year Reanalysis, European Centre for Medium-Range Weather Forecasts Reanalysis-40, Interim Reanalysis, National Centers for Environmental Prediction Climate Forecast System Reanalysis, and NASA's Modern Era Retrospective Analysis for Research and Application (MERRA). Most of the reanalyses reproduce a reasonable global spatial distribution of observed TCs and temporal interannual variation of total TC frequency. Of the six reanalysis data sets, JRA-55 appears to be the best in terms of the following: the highest skill for spatial and temporal distribution of TC frequency of occurrence, highest TC hitting rate, lower false alarm rate, reasonable TC structure in terms of the relationship between maximum surface wind speed and sea level pressure, and higher correlation coefficients for interannual variations of TC frequency. These results also suggest that the finest-resolution reanalysis data sets, like MERRA, are not always the best in terms of TC climatology.

  17. Diurnal Variations of Clouds in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Wu, Qiaoyan; Ruan, Zhenxin

    2016-04-01

    Using 14 years (2000-2013) of pixel-resolution infrared (IR) brightness temperature data and best track data, this study estimates the diurnal variations of convective systems in tropical cyclones (TCs) in the western North Pacific. The very cold cloud cover (IR brightness temperatures < 208 K) of TCs reaches a maximum areal extent in the early morning (0000-0300 LST) and then decreases after the sunrise. The decrease of very cold cloud cover is followed by an increase of cloud cover between 208 K and 240 K with a maximum areal extent in the afternoon (1500-1800 LST). TC IR cloud top temperatures < 240 K have minimum values in the morning (0300-0600 LST) , while TC IR cloud top temperatures > 240 K have mean minimum values in the afternoon (1500-1800 LST). The out-of-phase relation between different cloud conditions with IR cloud top temperatures < 240 K and IR cloud top temperatures > 240 K lead to radius-averaged IR temperature show two minima within a day. Different diurnal evolution under different cloud conditions suggests that TC convective systems are better described in terms of both areal extent and cloud-top temperature. The maximum cloud cover with IR cloud top temperatures colder than 208 K in the morning and the maximum cloud cover with IR cloud top temperatures between 208 K and 240 K in the afternoon suggest that two different mechanisms might be involved with the diurnal variations of these two types of TC cloud conditions.

  18. Observed ocean waves by tropical cyclones

    NASA Astrophysics Data System (ADS)

    Zhang, Lin; Oey, Leo

    2017-04-01

    Ocean waves produced by tropical cyclones (TC) modify air-sea fluxes which in turn are crucial to the storms' intensity and development, yet they are poorly understood. Here we use 24 years (1992-2015) of observed waves, winds and TC-track information to stratify storm-centered composite maps of waves and winds according to TC intensities and translation speeds (Uh). While the wind field is rightward-asymmetric independent of Uh, the wave field is rightward-symmetric in concert with the wind for slow-translating TCs (Uh ≤ 3 m s-1), but right-rear asymmetric with strongest waves in the 4th quadrant for medium to fast-translating TCs (3 < Uh ≤ 7 m s-1), especially for the very fast storms (Uh > 7 m s-1), all independent of TC-intensity. The dominance of the right-rear asymmetry for fast-translating TCs appears to be related to the development of cross swells as the storms move faster, but further research using models are needed to understand the physical mechanisms.

  19. Observed strong currents under global tropical cyclones

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Chia; Tseng, Ruo-Shan; Chu, Peter C.; Chen, Jau-Ming; Centurioni, Luca R.

    2016-07-01

    Global data from drifters of the Surface Velocity Program (Niiler, 2001) and tropical cyclones (TCs) from the Joint Typhoon Warning Center and National Hurricane Center were analyzed to demonstrate strong ocean currents and their characteristics under various storm intensities in the Northern Hemisphere (NH) and in the Southern Hemisphere (SH). Mean TC's translation speed (Uh) is faster in the NH (~ 4.7 m s- 1) than in the SH (~ 4.0 m s- 1), owing to the fact that TCs are more intense in the NH than in the SH. The rightward (leftward) bias of ocean mixed-layer (OML) velocity occurs in the NH (SH). As a result of this slower Uh and thus a smaller Froude number in the SH, the flow patterns in the SH under the same intensity levels of TCs are more symmetric relative to the TC center and the OML velocities are stronger. This study provides the first characterization of the near-surface OML velocity response to all recorded TCs in the SH from direct velocity measurements.

  20. Assessing the Importance of Atlantic Basin Tropical Cyclone Steering Currents in Anticipating Landfall Risk

    NASA Astrophysics Data System (ADS)

    Truchelut, R.; Hart, R. E.

    2013-12-01

    While a number of research groups offer quantitative pre-seasonal assessments of aggregate annual Atlantic Basin tropical cyclone activity, the literature is comparatively thin concerning methods to meaningfully quantify seasonal U.S. landfall risks. As the example of Hurricane Andrew impacting Southeast Florida in the otherwise quiet 1992 season demonstrates, an accurate probabilistic assessment of seasonal tropical cyclone threat levels would be of immense public utility and economic value; however, the methods used to predict annual activity demonstrate little skill for predicting annual count of landfalling systems of any intensity bin. Therefore, while current models are optimized to predict cumulative seasonal tropical cyclone activity, they are not ideal tools for assessing the potential for sensible impacts of storms on populated areas. This research aims to bridge the utility gap in seasonal tropical cyclone forecasting by shifting the focus of seasonal modelling to the parameters that are most closely linked to creating conditions favorable for U.S. landfalls, particularly those of destructive and costly intense hurricanes. As it is clear from the initial findings of this study that overall activity has a limited influence on sensible outcomes, this project concentrates on detecting predictability and trends in cyclogenesis location and upper-level wind steering patterns. These metrics are demonstrated to have a relationship with landfall activity in the Atlantic Basin climatological record. By aggregating historic seasonally-averaged steering patterns using newly-available reanalysis model datasets, some atmospheric and oceanic precursors to an elevated risk of North American tropical cyclone landfall have been identified. Work is ongoing to quantify the variance, persistence, and predictability of such patterns over seasonal timescales, with the aim of yielding tools that could be incorporated into tropical cyclone risk mitigation strategies.

  1. Contrasting tropical cyclone and non-tropical cyclone related rainfall drop size distribution at Darwin, Australia

    NASA Astrophysics Data System (ADS)

    Deo, Anil; Walsh, Kevin J. E.

    2016-11-01

    In this study the rainfall drop size distribution (DSD) during the passage of seven tropical cyclones (TCs) over Darwin is compared and contrasted with that associated with non-tropical cyclone (non-TC) events, using the impact disdrometer data at the Darwin Atmospheric Radiation and Measurement (ARM) site. The disparity of the DSD with respect to rainfall types (between TC and non-TC conditions) and distance from TC centre is also examined. It is shown that TC DSDs are statistically different from the non-TC DSDs, the former encompassing a larger concentration of small to moderate drop sizes. The TC mass-weighted mean diameter (Dm) is lower than the non-TC values at all rain rates and also for the different precipitation types (convective, transition and stratiform). The TC DSD varies with distance from the TC centre, as rainfall near the TC centre (< 60 km) comprises of relatively smaller drops which are strongly evident at small to moderate rain rates (< 30 mm h- 1). Such variations in the DSD have implications for the parameters used in the algorithm that converts radar reflectivity to rainfall rate in TCs, as well as for the analytical expressions used in describing the observed DSD employed in cloud modelling parameterizations.

  2. Tropical cyclone flow asymmetries induced by a uniform flow revisited

    NASA Astrophysics Data System (ADS)

    Thomsen, Gerald L.; Smith, Roger K.; Montgomery, Michael T.

    2015-09-01

    We investigate the hypothesized effects of a uniform flow on the structural evolution of a tropical cyclone using a simple idealized, three-dimensional, convection-permitting, numerical model. The study addresses three outstanding basic questions concerning the effects of moist convection on the azimuthal flow asymmetries and provides a bridge between the problem of tropical cyclone intensification in a quiescent environment and that in vertical shear over a deep tropospheric layer. At any instant of time, explicit deep convection in the model generates flow asymmetries that tend to mask the induced flow asymmetries predicted by the dry, slab boundary layer model of Shapiro, whose results are frequently invoked as a benchmark for characterizing the boundary layer-induced vertical motion for a translating storm. In sets of ensemble experiments in which the initial low-level moisture field is randomly perturbed, time-averaged ensemble mean fields in the mature stage show a coherent asymmetry in the vertical motion rising into the eyewall and in the total (horizontal) wind speed just above the boundary layer. The maximum ascent occurs about 45° to the left of the vortex motion vector, broadly in support of Shapiro's results, in which it occurs ahead of the storm, and consistent with one earlier more complex numerical calculation by Frank and Ritchie. The total wind asymmetry just above the boundary layer has a maximum in the forward right sector, which is in contrast to the structure effectively prescribed by Shapiro based on an inviscid dry symmetric vortex translating in a uniform flow where, in an Earth-relative frame, the maximum is on the right.

  3. Revisiting the Future Projections of Tropical Cyclones Intensity

    NASA Astrophysics Data System (ADS)

    Liu, H.; Foltz, G. R.

    2016-12-01

    The varying atmospheric and oceanic states impact the tropical cyclone intensity on both short-term weather time scales and long-term climate time scales. In a warming climate, the changes of environmental conditions of the atmosphere and ocean are not uniform and it is complicated to estimate the net influence on tropical cyclones. This study adopts the recently improved Dynamic Potential Intensity (DPI) which applies the depth averaged temperature and involves the subsurface salinity-induced stratification information. By using the Simple Ocean Data Assimilation reanalysis, and the IBTrACS (International Best Track Archive for Climate Stewardship) tropical cyclone best track data, a minimum DPI threshold is established for the intensification of TCs into category five hurricanes or typhoons in different regions of global tropical cyclones. The projected changes in accordance with the established minimum threshold under the CMIP5 RCP 4.5 and 8.5 scenarios are further analyzed using the ensemble DPI mean from CMIP5 models. The role of salinity is estimated. Results suggest that the depth averaged temperature which includes the effect of salinity stratification will continue to rise attributed to greenhouse gas emissions (GHG). However, the projected atmosphere condition in the future largely compensates for the influences of ocean temperature increases on the intensity of tropical cyclones.

  4. Infectious Diseases and Tropical Cyclones in Southeast China.

    PubMed

    Zheng, Jietao; Han, Weixiao; Jiang, Baofa; Ma, Wei; Zhang, Ying

    2017-05-07

    Southeast China is frequently hit by tropical cyclones (TCs) with significant economic and health burdens each year. However, there is a lack of understanding of what infectious diseases could be affected by tropical cyclones. This study aimed to examine the impacts of tropical cyclones on notifiable infectious diseases in southeast China. Disease data between 2005 and 2011 from four coastal provinces in southeast China, including Guangdong, Hainan, Zhejiang, and Fujian province, were collected. Numbers of cases of 14 infectious diseases were compared between risk periods and reference periods for each tropical cyclone. Risk ratios (RRs) were calculated to estimate the risks. TCs were more likely to increase the risk of bacillary dysentery, paratyphoid fever, dengue fever and acute hemorrhagic conjunctivitis (ps < 0.05) than to decrease the risk, more likely to decrease the risk of measles, mumps, varicella and vivax malaria (ps < 0.05) than to increase the risk. In conclusion, TCs have mixed effects on the risk of infectious diseases. TCs are more likely to increase the risk of intestinal and contact transmitted infectious diseases than to decrease the risk, and more likely to decrease the risk of respiratory infectious diseases than to increase the risk. Findings of this study would assist in developing public health strategies and interventions for the reduction of the adverse health impacts from tropical cyclones.

  5. Infectious Diseases and Tropical Cyclones in Southeast China

    PubMed Central

    Zheng, Jietao; Han, Weixiao; Jiang, Baofa; Ma, Wei; Zhang, Ying

    2017-01-01

    Southeast China is frequently hit by tropical cyclones (TCs) with significant economic and health burdens each year. However, there is a lack of understanding of what infectious diseases could be affected by tropical cyclones. This study aimed to examine the impacts of tropical cyclones on notifiable infectious diseases in southeast China. Disease data between 2005 and 2011 from four coastal provinces in southeast China, including Guangdong, Hainan, Zhejiang, and Fujian province, were collected. Numbers of cases of 14 infectious diseases were compared between risk periods and reference periods for each tropical cyclone. Risk ratios (RRs) were calculated to estimate the risks. TCs were more likely to increase the risk of bacillary dysentery, paratyphoid fever, dengue fever and acute hemorrhagic conjunctivitis (ps < 0.05) than to decrease the risk, more likely to decrease the risk of measles, mumps, varicella and vivax malaria (ps < 0.05) than to increase the risk. In conclusion, TCs have mixed effects on the risk of infectious diseases. TCs are more likely to increase the risk of intestinal and contact transmitted infectious diseases than to decrease the risk, and more likely to decrease the risk of respiratory infectious diseases than to increase the risk. Findings of this study would assist in developing public health strategies and interventions for the reduction of the adverse health impacts from tropical cyclones. PMID:28481286

  6. Satellite-based Tropical Cyclone Monitoring Capabilities

    NASA Astrophysics Data System (ADS)

    Hawkins, J.; Richardson, K.; Surratt, M.; Yang, S.; Lee, T. F.; Sampson, C. R.; Solbrig, J.; Kuciauskas, A. P.; Miller, S. D.; Kent, J.

    2012-12-01

    Satellite remote sensing capabilities to monitor tropical cyclone (TC) location, structure, and intensity have evolved by utilizing a combination of operational and research and development (R&D) sensors. The microwave imagers from the operational Defense Meteorological Satellite Program [Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS)] form the "base" for structure observations due to their ability to view through upper-level clouds, modest size swaths and ability to capture most storm structure features. The NASA TRMM microwave imager and precipitation radar continue their 15+ yearlong missions in serving the TC warning and research communities. The cessation of NASA's QuikSCAT satellite after more than a decade of service is sorely missed, but India's OceanSat-2 scatterometer is now providing crucial ocean surface wind vectors in addition to the Navy's WindSat ocean surface wind vector retrievals. Another Advanced Scatterometer (ASCAT) onboard EUMETSAT's MetOp-2 satellite is slated for launch soon. Passive microwave imagery has received a much needed boost with the launch of the French/Indian Megha Tropiques imager in September 2011, basically greatly supplementing the very successful NASA TRMM pathfinder with a larger swath and more frequent temporal sampling. While initial data issues have delayed data utilization, current news indicates this data will be available in 2013. Future NASA Global Precipitation Mission (GPM) sensors starting in 2014 will provide enhanced capabilities. Also, the inclusion of the new microwave sounder data from the NPP ATMS (Oct 2011) will assist in mapping TC convective structures. The National Polar orbiting Partnership (NPP) program's VIIRS sensor includes a day night band (DNB) with the capability to view TC cloud structure at night when sufficient lunar illumination exits. Examples highlighting this new capability will be discussed in concert with additional data fusion efforts.

  7. Temporal clustering of tropical cyclones and its ecosystem impacts

    PubMed Central

    Mumby, Peter J.; Vitolo, Renato; Stephenson, David B.

    2011-01-01

    Tropical cyclones have massive economic, social, and ecological impacts, and models of their occurrence influence many planning activities from setting insurance premiums to conservation planning. Most impact models allow for geographically varying cyclone rates but assume that individual storm events occur randomly with constant rate in time. This study analyzes the statistical properties of Atlantic tropical cyclones and shows that local cyclone counts vary in time, with periods of elevated activity followed by relative quiescence. Such temporal clustering is particularly strong in the Caribbean Sea, along the coasts of Belize, Honduras, Costa Rica, Jamaica, the southwest of Haiti, and in the main hurricane development region in the North Atlantic between Africa and the Caribbean. Failing to recognize this natural nonstationarity in cyclone rates can give inaccurate impact predictions. We demonstrate this by exploring cyclone impacts on coral reefs. For a given cyclone rate, we find that clustered events have a less detrimental impact than independent random events. Predictions using a standard random hurricane model were overly pessimistic, predicting reef degradation more than a decade earlier than that expected under clustered disturbance. The presence of clustering allows coral reefs more time to recover to healthier states, but the impacts of clustering will vary from one ecosystem to another. PMID:22006300

  8. Temporal clustering of tropical cyclones and its ecosystem impacts.

    PubMed

    Mumby, Peter J; Vitolo, Renato; Stephenson, David B

    2011-10-25

    Tropical cyclones have massive economic, social, and ecological impacts, and models of their occurrence influence many planning activities from setting insurance premiums to conservation planning. Most impact models allow for geographically varying cyclone rates but assume that individual storm events occur randomly with constant rate in time. This study analyzes the statistical properties of Atlantic tropical cyclones and shows that local cyclone counts vary in time, with periods of elevated activity followed by relative quiescence. Such temporal clustering is particularly strong in the Caribbean Sea, along the coasts of Belize, Honduras, Costa Rica, Jamaica, the southwest of Haiti, and in the main hurricane development region in the North Atlantic between Africa and the Caribbean. Failing to recognize this natural nonstationarity in cyclone rates can give inaccurate impact predictions. We demonstrate this by exploring cyclone impacts on coral reefs. For a given cyclone rate, we find that clustered events have a less detrimental impact than independent random events. Predictions using a standard random hurricane model were overly pessimistic, predicting reef degradation more than a decade earlier than that expected under clustered disturbance. The presence of clustering allows coral reefs more time to recover to healthier states, but the impacts of clustering will vary from one ecosystem to another.

  9. Synoptic and climatological aspects of extra-tropical cyclones

    NASA Astrophysics Data System (ADS)

    Leckebusch, G. C.

    2010-09-01

    Mid-latitude cyclones are highly complex dynamical features embedded in the general atmospheric circulation of the extra-tropics. Although the basic mechanisms leading to the formation of cyclones are commonly understood, the specific conditions and physical reasons triggering extreme, partly explosive development, are still under investigation. This includes also the identification of processes which might modulate the frequency and intensity of cyclone systems on time scales from days to centennials. This overview presentation will thus focus on three main topics: Firstly, the dynamic-synoptic structures of cyclones, the possibility to objectively identify cyclones and wind storms, and actual statistical properties of cyclone occurrence under recent climate conditions are addressed. In a second part, aspects of the interannual variability and its causing mechanisms are related to the seasonal predictability of extreme cyclones producing severe storm events. Extending the time frame will mean to deduce information on decadal or even centennial time periods. Thus, actual work to decadal as well as climatological variability and changes will be presented. In the last part of the talk focus will be laid on potential socio-economical impacts of changed cyclone occurrence. By means of global and regional climate modeling, future damages in terms of insured losses will be investigated and measures of uncertainty estimated from a multi-model ensemble analysis will be presented.

  10. Predictability of Tropical Cyclones Using the ECMWF Ensemble Prediction System

    NASA Astrophysics Data System (ADS)

    Belanger, J. I.; Webster, P. J.; Hoyos, C. H.; Curry, J. A.; Agudelo, P. A.

    2008-12-01

    The predictability of tropical cyclones using the ECMWF ensemble prediction system (EPS) is demonstrated with 3 severe cyclones in the Indian Ocean and 1 supertyphoon from the northwest Pacific, which include: Gonu, Sidr, and Man-Yi from 2007 and Nargis from 2008. While TC genesis forecasts are assumed to have little skill beyond 48 hours, we show that these projections can provide considerable lead-time with the ECMWF ensembles on average, correctly projecting the date of genesis and location of TC formation 5.5 days in advance. In addition, the ECMWF EPS shows considerable skill in track forecasts for both timing and location of movement especially in the 7 to 10 day range for all four tropical cyclones. While TC intensity forecasts are generally underestimated - attributed to the reduced resolution in the ECMWF ensembles - these intensity projections, especially for large tropical cyclones, can provide several days of additional lead-time that is not currently provided. This extra lead-time is vitally important in countries where coastal evacuations and disaster preparations are particularly slow. The potential forecasting benefits using the ECMWF EPS for tropical cyclones is reviewed in conjunction with a separate presentation in how this information can be used to mitigate disaster risk for countries in coastal areas of the Northern Indian Ocean.

  11. On the Relationship between Tropical Moisture Exports and Extratropical Cyclones

    NASA Astrophysics Data System (ADS)

    Knippertz, Peter; Wernli, Heini; Gläser, Gregor; Boleti, Eirini; Joos, Hanna; Binder, Hanin

    2016-04-01

    Tropical moisture export (TME) events are an important element of the global circulation and contribute significantly to regional precipitation. They are defined here on the basis of trajectories starting in the tropical troposphere and reaching a water vapor flux of at least 100 g kg-1 m s-1 poleward of 35° latitude. TME frequency shows four marked occurrence maxima in both hemispheres with varying seasonal cycles. In some cases TMEs can be linked to similar phenomena of atmospheric flow such as Warm Conveyor Belts (WCBs) or Atmospheric Rivers (ARs). For example, 90% of all ARs affecting the US West Coast during December-May are connected to TME events, but the tropical moisture source is less important during the more active AR season June-November. In addition to these climatological TME characteristics we discuss two aspects of their relationship to extratropical cyclones: Case studies indicate that (i) cyclones traveling along the southern fringes of the midlatitude storm track can instigate the export of tropical moisture ahead of their cold fronts, and (ii) the tropical moisture can fuel latent heat release in the cyclone and therefore contribute to its intensification. A long-term statistical analysis of passages of TME trajectories through areas with closed isobars surrounding active cyclones in the northern hemisphere reveals a surprisingly small number of encounters, particularly in winter. The majority of hits occur south of 40°N and there is no statistically significant relationship with cyclone intensification. The results suggest that TMEs often pass relatively far from cyclone centers where vertical motions tend to be moderate. This prevents an early rainout of the tropical moisture and allows the export into higher latitudes. For the same reasons we expect TMEs to "avoid" WCBs with roots at low latitudes. This interpretation is consistent with the fact that most TME maxima are located along the western flanks of subtropical high-pressure systems.

  12. On the Relationship between Tropical Moisture Exports and Extratropical Cyclones

    NASA Astrophysics Data System (ADS)

    Knippertz, P.; Wernli, H.; Gläser, G.; Boleti, E.; Joos, H.; Binder, H.

    2015-12-01

    Tropical moisture export (TME) events are an important element of the global circulation and contribute significantly to regional precipitation. They are defined here on the basis of trajectories starting in the tropical troposphere and reaching a water vapor flux of at least 100 g kg-1 m s-1 poleward of 35° latitude. TME frequency shows four marked occurrence maxima in both hemispheres with varying seasonal cycles. In some cases TMEs can be linked to similar phenomena of atmospheric flow such as Warm Conveyor Belts (WCBs) or Atmospheric Rivers (ARs). For example, 90% of all ARs affecting the US West Coast during December-May are connected to TME events, but the tropical moisture source is less important during the more active AR season June-November. In addition to these climatological TME characteristics we discuss two aspects of their relationship to extratropical cyclones: Case studies indicate that (i) cyclones traveling along the southern fringes of the midlatitude storm track can instigate the export of tropical moisture ahead of their cold fronts, and (ii) the tropical moisture can fuel latent heat release in the cyclone and therefore contribute to its intensification. A long-term statistical analysis of passages of TME trajectories through areas with closed isobars surrounding active cyclones in the northern hemisphere reveals a surprisingly small number of encounters, particularly in winter. The majority of hits occur south of 40°N and there is no statistically significant relationship with cyclone intensification. The results suggest that TMEs often pass relatively far from cyclone centers where vertical motions tend to be moderate. This prevents an early rainout of the tropical moisture and allows the export into higher latitudes. For the same reasons we expect TMEs to "avoid" WCBs with roots at low latitudes. This interpretation is consistent with the fact that most TME maxima are located along the western flanks of subtropical high-pressure systems.

  13. TRMM Flyby of Tropical Cyclone Narelle

    NASA Image and Video Library

    This animated, 3-D flyby of Major Cyclone Narelle was created using data on Jan. 11, from NASA's TRMM satellite. Narelle's wind speeds were near 132 mph. A few thunderstorm towers in Narelle's eye ...

  14. Revisiting the steering principal of tropical cyclone motion in a numerical experiment

    NASA Astrophysics Data System (ADS)

    Wu, Liguang; Chen, Xiaoyu

    2016-12-01

    The steering principle of tropical cyclone motion has been applied to tropical cyclone forecasting and research for nearly 100 years. Two fundamental questions remain unanswered. One is why the steering flow plays a dominant role in tropical cyclone motion, and the other is when tropical cyclone motion deviates considerably from the steering. A high-resolution numerical experiment was conducted with the tropical cyclone in a typical large-scale monsoon trough over the western North Pacific. The simulated tropical cyclone experiences two eyewall replacement processes. Based on the potential vorticity tendency (PVT) diagnostics, this study demonstrates that the conventional steering, which is calculated over a certain radius from the tropical cyclone center in the horizontal and a deep pressure layer in the vertical, plays a dominant role in tropical cyclone motion since the contributions from other processes are largely cancelled out due to the coherent structure of tropical cyclone circulation. Resulting from the asymmetric dynamics of the tropical cyclone inner core, the trochoidal motion around the mean tropical cyclone track cannot be accounted for by the conventional steering. The instantaneous tropical cyclone motion can considerably deviate from the conventional steering that approximately accounts for the combined effect of the contribution of the advection of the symmetric potential vorticity component by the asymmetric flow and the contribution from the advection of the wave-number-one potential vorticity component by the symmetric flow.

  15. Wind waves in tropical cyclones: satellite altimeter observations and modeling

    NASA Astrophysics Data System (ADS)

    Golubkin, Pavel; Kudryavtsev, Vladimir; Chapron, Bertrand

    2016-04-01

    Results of investigation of wind-wave generation by tropical cyclones using satellite altimeter data are presented. Tropical cyclones are generally relatively small rapidly moving low pressure systems that are capable of generating severe wave conditions. Translation of a tropical cyclone leads to a prolonged period of time surface waves in the right sector remain under high wind forcing conditions. This effect has been termed extended fetch, trapped fetch or group velocity quasi-resonance. A tropical cyclone wave field is thus likely more asymmetrical than the corresponding wind field: wind waves in the tropical cyclone right sector are more developed with larger heights than waves in the left one. A dataset of satellite altimeter intersections of the Western Pacific tropical cyclones was created for 2010-2013. Data from four missions were considered, i.e., Jason-1, Jason-2, CryoSat-2, SARAL/AltiKa. Measurements in the rear-left and front-right sectors of tropical cyclones were examined for the presence of significant wave asymmetry. An analytical model is then derived to efficiently describe the wave energy distribution in a moving tropical cyclone. The model essentially builds on a generalization of the self-similar wave growth model and the assumption of a strongly dominant single spectral mode in a given quadrant of the storm. The model provides a criterion to anticipate wave enhancement with the generation of trapped abnormal waves. If forced during a sufficient timescale interval, also defined from this generalized self-similar wave growth model, waves can be trapped and large amplification of the wave energy will occur in the front-right storm quadrant. Remarkably, the group velocity and corresponding wavelength of outrunning wave systems will become wind speed independent and solely relate to the translating velocity. The resulting significant wave height also only weakly depends on wind speed, and more strongly on the translation velocity. Satellite

  16. Extreme weather: Subtropical floods and tropical cyclones

    NASA Astrophysics Data System (ADS)

    Shaevitz, Daniel A.

    Extreme weather events have a large effect on society. As such, it is important to understand these events and to project how they may change in a future, warmer climate. The aim of this thesis is to develop a deeper understanding of two types of extreme weather events: subtropical floods and tropical cyclones (TCs). In the subtropics, the latitude is high enough that quasi-geostrophic dynamics are at least qualitatively relevant, while low enough that moisture may be abundant and convection strong. Extratropical extreme precipitation events are usually associated with large-scale flow disturbances, strong ascent, and large latent heat release. In the first part of this thesis, I examine the possible triggering of convection by the large-scale dynamics and investigate the coupling between the two. Specifically two examples of extreme precipitation events in the subtropics are analyzed, the 2010 and 2014 floods of India and Pakistan and the 2015 flood of Texas and Oklahoma. I invert the quasi-geostrophic omega equation to decompose the large-scale vertical motion profile to components due to synoptic forcing and diabatic heating. Additionally, I present model results from within the Column Quasi-Geostrophic framework. A single column model and cloud-revolving model are forced with the large-scale forcings (other than large-scale vertical motion) computed from the quasi-geostrophic omega equation with input data from a reanalysis data set, and the large-scale vertical motion is diagnosed interactively with the simulated convection. It is found that convection was triggered primarily by mechanically forced orographic ascent over the Himalayas during the India/Pakistan flood and by upper-level Potential Vorticity disturbances during the Texas/Oklahoma flood. Furthermore, a climate attribution analysis was conducted for the Texas/Oklahoma flood and it is found that anthropogenic climate change was responsible for a small amount of rainfall during the event but the

  17. Contribution of tropical cyclones to global rainfall

    NASA Astrophysics Data System (ADS)

    Khouakhi, Abdou; Villarini, Gabriele; Vecchi, Gabriel; Smith, James

    2016-04-01

    Rainfall associated with tropical cyclones (TCs) can have both devastating and beneficial impacts in different parts of the world. In this work, daily precipitation and historical six-hour best track TC datasets are used to quantify the contribution of TCs to global rainfall. We select 18607 rain gauge stations with at least 25 complete (at least 330 measurements per year) years between 1970 and 2014. We consider rainfall associated with TCs if the center of circulation of the storm passed within a given distance from the rain gauge and within a given time window. Spatial and temporal sensitivity analyses are performed with varying time windows (same day, ±1 day) and buffer radii (400 km and 500 km) around each rain gauge. Results highlight regional differences in TC-induced rainfall. The highest TC-induced precipitation totals (400 to 600+ mm/year) are prevalent along eastern Asia, western and northeastern Australia, and in the western Pacific islands. Stations along the southeast of the U.S. coast and surrounding the Gulf of Mexico receive up to 200 mm/year of TC rainfall. The highest annual fractional contributions of TCs to total rainfall (from 35 to 50%) are recorded in stations located in northwestern Australia, southeastern China, the northern Philippines and the southern Mexico peninsula. Seasonally, the highest proportions (40 to 50%) are recorded along eastern Australia and Mauritius in winter, and in eastern Asia and Mexico in summer and autumn. Analyses of the relative contribution of TCs to extreme rainfall using annual maximum (AM) and peaks-over-threshold (POT) approaches indicate notable differences among regions. The highest TC-AM rainfall proportions (45 to 60%) are found in stations located in Japan, eastern China, the Philippines, eastern and western Australia. Substantial contributions (25 to 40% of extreme rainfall) are also recorded in stations located along the U.S. East Coast, the Gulf of Mexico, and the Mexico peninsula. We find similar

  18. Training on Eastern Pacific tropical cyclones for Latin American students

    NASA Astrophysics Data System (ADS)

    Farfán, L. M.; Raga, G. B.

    2009-05-01

    Tropical cyclones are one of the most impressive atmospheric phenomena and their development in the Atlantic and Eastern Pacific basins has potential to affect several Latin-American and Caribbean countries, where human resources are limited. As part of an international research project, we are offering short courses based on the current understanding of tropical cyclones in the Eastern Pacific basin. Our main goal is to train students from higher-education institutions from various countries in Latin America. Key aspects are tropical cyclone formation and evolution, with particular emphasis on their development off the west coast of Mexico. Our approach includes lectures on tropical cyclone climatology and formation, dynamic and thermodynamic models, air-sea interaction and oceanic response, ocean waves and coastal impacts as well as variability and climate-related predictions. In particular, we use a best-track dataset issued by the United States National Hurricane Center and satellite observations to analyze convective patterns for the period 1970-2006. Case studies that resulted in landfall over northwestern Mexico are analyzed in more detail; this includes systems that developed during the 2006, 2007 and 2008 seasons. Additionally, we have organized a human-dimensions symposium to discuss socio-economic issues that are associated with the landfall of tropical cyclones. This includes coastal zone impact and flooding, the link between cyclones and water resources, the flow of weather and climate information from scientists to policy- makers, the role of emergency managers and decision makers, impact over health issues and the viewpoint of the insurance industry.

  19. A comparative study on the genesis of North Indian Ocean tropical cyclone Madi (2013) and Atlantic Ocean tropical cyclone Florence (2006)

    NASA Astrophysics Data System (ADS)

    Rajasree, V. P. M.; Kesarkar, Amit P.; Bhate, Jyoti N.; Singh, Vikas; Umakanth, U.; Varma, T. Harish

    2016-12-01

    A modeling study has been carried out to understand the similarities and differences in the genesis sequence of a Bay of Bengal tropical cyclone Madi (6-13 December 2013) and the Atlantic Ocean tropical cyclone Florence (3-12 September 2006) on the applicability of hypotheses of the marsupial theory of tropical cyclogenesis. We examined the role of the protective pouch and warm core formation during their genesis and intensification phases. We have chosen tropical cyclone Madi and tropical cyclone Florence for our study specifically due to both of these tropical cyclones originated from westward moving parent disturbance embedded in the intertropical convergence zone. Also, the genesis and intensification of tropical cyclone Florence were accompanied by a series of Saharan dust outbreaks. Our results indicated that the dry air intrusion was not a dominant detrimental factor for the genesis of tropical cyclone Madi and showed rapid intensification within the pouch region. However, in the case of the tropical cyclone Florence, the delay in the intensification as a category 1 tropical cyclone from its tropical depression stage was due to entrainment of the dry air into the core of cyclonic vortex up to 700 hPa from above. The results from this study showed that the wave pouch played a most significant role in the vorticity upscale cascade (First hypothesis) and moisture aggregation (Second hypothesis) in pregenesis period of both the tropical cyclones. It also prevented the lateral dry air intrusion (Second hypothesis) from the Saharan Air Layer during the genesis phase of tropical cyclone Florence.

  20. Contributions of Tropical Cyclones to the North Atlantic Climatological Rainfall as Observed from Satellites

    NASA Technical Reports Server (NTRS)

    Rodgers, Edward B.; Adler, Robert F.; Pierce, Harold F.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The tropical cyclone rainfall climatology study that was performed for the North Pacific was extended to the North Atlantic. Similar to the North Pacific tropical cyclone study, mean monthly rainfall within 444 km of the center of the North Atlantic tropical cyclones (i.e., that reached storm stage and greater) was estimated from passive microwave satellite observations during, an eleven year period. These satellite-observed rainfall estimates were used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and inter-annual distribution of the North Atlantic total rainfall during, June-November when tropical cyclones were most abundant. The main results from this study indicate: 1) that tropical cyclones contribute, respectively, 4%, 3%, and 4% to the western, eastern, and entire North Atlantic; 2) similar to that observed in the North Pacific, the maximum in North Atlantic tropical cyclone rainfall is approximately 5 - 10 deg poleward (depending on longitude) of the maximum non-tropical cyclone rainfall; 3) tropical cyclones contribute regionally a maximum of 30% of the total rainfall 'northeast of Puerto Rico, within a region near 15 deg N 55 deg W, and off the west coast of Africa; 4) there is no lag between the months with maximum tropical cyclone rainfall and non-tropical cyclone rainfall in the western North Atlantic, while in the eastern North Atlantic, maximum tropical cyclone rainfall precedes maximum non-tropical cyclone rainfall; 5) like the North Pacific, North Atlantic tropical cyclones Of hurricane intensity generate the greatest amount of rainfall in the higher latitudes; and 6) warm ENSO events inhibit tropical cyclone rainfall.

  1. Understanding the impact of model resolution on tropical cyclones in CAM5 using rotating radiative-convective equilibrium

    NASA Astrophysics Data System (ADS)

    Reed, Kevin; Chavas, Daniel

    2015-04-01

    In our continued effort to understand the climate system and improve its representation in general circulation models (GCMs) it is crucial to develop new methods to evaluate these models. This is certainly true as the GCM community advances towards high horizontal resolutions (i.e., grid spacing less than 0.5 degrees), which will require interpreting and improving the performance of many model components. Of specific interest is the simulation of tropical cyclones at these spatial scales. Idealized, or reduced complexity, frameworks can be used to investigate how model assumptions impact behavior across scales. Here we explore the implication of horizontal resolution on tropical cyclones in GCMs using an idealized global rotating radiative-convective equilibrium (RCE) configuration. The National Center for Atmospheric Research and U.S. Department of Energy supported Community Atmosphere Model 5 (CAM5) is configured for an ocean-covered earth with diurnally varying, spatially uniform insolation and spatially uniform rotation, a setup that permits the formation of tropical cyclones throughout the entire global domain. CAM5 is run with the spectral element dynamics package at two horizontal resolutions: a standard resolution of approximately 1 degree grid spacing and a high-resolution of approximately 0.25 degree grid spacing. In this unique testbed, the statistics of tropical cyclone intensity and outer size, as measured by the azimuthal-mean radius of 12 m/s, are analyzed under both configurations. Implications of the results for both model development and tropical cyclone physics are discussed.

  2. Impact of Vertical Wind Shear on Tropical Cyclone Rainfall

    NASA Technical Reports Server (NTRS)

    Cecil, Dan; Marchok, Tim

    2014-01-01

    While tropical cyclone rainfall has a large axisymmetric component, previous observational and theoretical studies have shown that environmental vertical wind shear leads to an asymmetric component of the vertical motion and precipitation fields. Composites consistently depict a precipitation enhancement downshear and also cyclonically downwind from the downshear direction. For consistence with much of the literature and with Northern Hemisphere observations, this is subsequently referred to as "Downshear-Left". Stronger shear magnitudes are associated with greater amplitude precipitation asymmetries. Recent work has reinforced the prior findings, and explored details of the response of the precipitation and kinematic fields to environmental vertical wind shear. Much of this research has focused on tropical cyclones away from land, to limit the influence of other processes that might distort the signal related to vertical wind shear. Recent evidence does suggest vertical wind shear can also play a major role in precipitation asymmetries during and after landfall.

  3. A statistical analysis of the association between tropical cyclone intensity change and tornado frequency

    NASA Astrophysics Data System (ADS)

    Moore, Todd W.

    2016-07-01

    Tropical cyclones often produce tornadoes that have the potential to compound the injury and fatality counts and the economic losses associated with tropical cyclones. These tornadoes do not occur uniformly through time or across space. Multiple statistical methods were used in this study to analyze the association between tropical cyclone intensity change and tornado frequency. Results indicate that there is an association between the two and that tropical cyclones tend to produce more tornadoes when they are weakening, but the association is weak. Tropical cyclones can also produce a substantial number of tornadoes when they are relatively stable or strengthening.

  4. NASA Analyzes Tropical Cyclone Kyant Before its Demise

    NASA Image and Video Library

    The GPM core observatory satellite flew over tropical cyclone Kyant on Oct. 25 at 12:06 p.m. EDT. An area of violent storms was dropping rain at a rate of over 215 mm (8.5 inches) per hour (red). A...

  5. African Lightning: Indicator of Tropical Atlantic Cyclone Formation

    NASA Astrophysics Data System (ADS)

    Chronis, Themis; Williams, Earle; Anagnostou, Emmanouil; Petersen, Walter

    2007-10-01

    Each year, devastating hurricanes originating from the tropical Atlantic Ocean cause severe loss of life and property damage. Efforts to predict and forecast the behavior of such phenomena range from satellite-derived sea surface temperatures to coupled ocean-atmosphere models. Nonetheless, predicting cyclone occurrence and behavior remains elusive.

  6. Augmentation of Early Intensity Forecasting in Tropical Cyclones

    DTIC Science & Technology

    2011-09-30

    1 Augmentation of Early Intensity Forecasting in Tropical Cyclones J . Scott Tyo College of Optical Sciences University of Arizona Tucson, AZ...at the University of Arizona is composed of the following members (italicized members are no longer working on the project):  J . Scott Tyo, PI

  7. GPM Flyby of Tropical Cyclone Ula's Eye and Rainfall

    NASA Image and Video Library

    NASA Sees Tropical Cyclone Ula's Eye and Rainfall On Dec. 29, NASA's GPM saw rain was falling at a rate of over 83.6 mm (3.29 inches) per in a feeder band (of thunderstorms) northeast of the develo...

  8. Jason Tracks Powerful Tropical Cyclone Gonu High Winds, Waves

    NASA Image and Video Library

    2007-06-08

    This pair of images from the radar altimeter instrument on NASA U.S./France Jason mission reveals information on wind speeds and wave heights of Tropical Cyclone Gonu, which reached Category 5 strength in the Arabian Sea prior to landfall in early June.

  9. A 6000 year tropical cyclone record from Western Australia

    NASA Astrophysics Data System (ADS)

    Nott, Jonathan

    2011-03-01

    This study provides the first long-term tropical cyclone record from the Indian Ocean region. Multiple shore parallel ridges composed entirely of one species of marine cockle shell ( Fragum eragatum) standing between 3 and 6 m above mean sea level occur at Hamelin Pool, Shark Bay, Western Australia. The ridges record a tropical cyclone history between approximately 500 cal BP and 6000-7000 cal BP. Numerical storm surge and shallow water wave modelling techniques have been applied to determine the intensity (central pressure with uncertainty margins) of the storms responsible for deposition of the ridges, which has occurred approximately every 190-270 years. The ridges also record a 1700 year gap in tropical cyclone activity, between approximately 5400 cal BP and 3700 cal BP, where ridges deposited prior to this time were buried by a substantial deposit of aeolian fine-grained terrestrial sediment. The presence of this sedimentary unit suggests that this 1700 year period was characterised by a very dry climate; possibly the driest phase experienced in this region since the mid-Holocene. The absence of tropical cyclones at this time and the occurrence of this mega-drought may be linked.

  10. Tropical storms: The socio-economics of cyclones

    NASA Astrophysics Data System (ADS)

    Noy, Ilan

    2016-04-01

    Understanding the potential social and economic damage and loss wrought by tropical cyclones requires not only understanding how they will change in frequency and intensity in a future climate, but also how these hazards will interact with the changing exposures and vulnerabilities associated with social change.

  11. In-Situ Observations in Tropical Cyclones from Ocean Drifters

    NASA Astrophysics Data System (ADS)

    Morzel, J.; Centurioni, L. R.

    2013-05-01

    Ocean Drifters are cost effective, robust and high-quality instruments currently used to observe important variables in the ocean and atmosphere boundary layers during tropical cyclones. They have been configured to measure sea level atmospheric air pressure, wind velocity, solar insolation, sea surface and sub-surface temperature, ocean mixed-layer currents and three-dimensional ocean velocity (typically in depths of 0-150m). Ocean drifters have been successfully deployed in seven hurricanes (Atlantic Ocean) and in four typhoons (Pacific Ocean). Drifters are air-deployed about 18-24 hours ahead of an approaching tropical cyclone from a C-130J aircraft by the 53rd WRS "Hurricane Hunters" at a spacing of 30-50km in a line perpendicular to the expected storm track. On average, the tropical cyclone center has passed within 20km of the nearest drifter, and as close as 3km. Measurements are taken every 15 minutes and are transmitted via Argos or Iridium satellites in real-time and posted to the Global Telecommunication System of the World Weather Watch. The instrument success rate has been 92% in all previous deployments during tropical cyclone conditions from Cat-1 to Cat-5. The high quality of drifter observations has been validated with co-located measurements from dropwindsondes, nearby ocean profiling floats and satellites. Distinct features of the coupled tropical cyclone atmosphere-ocean system observed by the drifters include: the exponential decrease of sea level pressure towards the minimum at the storm center, the radius of maximum winds and their strength, the cold ocean wake on the right hand side of the storm, the inertial currents in the upper ocean, the downward propagation of inertial waves in the ocean, the relatively fast recovery of the sea surface temperature in the cold wake and the longer endurance of the sub-surface wake. In addition, the drifters have detected the response of the atmospheric boundary layer to the ocean's cold wake by measuring

  12. Sensitivity of tropical cyclone intensification to inner-core structure

    NASA Astrophysics Data System (ADS)

    Ge, Xuyang; Xu, Wei; Zhou, Shunwu

    2015-10-01

    In this study, the dependence of tropical cyclone (TC) development on the inner-core structure of the parent vortex is examined using a pair of idealized numerical simulations. It is found that the radial profile of inner-core relative vorticity may have a great impact on its subsequent development. For a system with a larger inner-core relative vorticity/inertial stability, the conversion ratio of the diabatic heating to kinetic energy is greater. Furthermore, the behavior of the convective vorticity eddies is likely modulated by the system-scale circulation. For a parent vortex with a relatively higher inner-core vorticity and larger negative radial vorticity gradient, convective eddy formation and radially inward propagation is promoted through vorticity segregation. This provides a greater potential for these small-scale convective cells to self-organize into a mesoscale inner-core structure in the TC. In turn, convectively induced diabatic heating that is close to the center, along with higher inertial stability, efficiently enhances system-scale secondary circulation. This study provides a solid basis for further research into how the initial structure of a TC influences storm dynamics and thermodynamics.

  13. Tropical Cyclone Induced Air-Sea Interactions Over Oceanic Fronts

    NASA Astrophysics Data System (ADS)

    Shay, L. K.

    2012-12-01

    Recent severe tropical cyclones underscore the inherent importance of warm background ocean fronts and their interactions with the atmospheric boundary layer. Central to the question of heat and moisture fluxes, the amount of heat available to the tropical cyclone is predicated by the initial mixed layer depth and strength of the stratification that essentially set the level of entrainment mixing at the base of the mixed layer. In oceanic regimes where the ocean mixed layers are thin, shear-induced mixing tends to cool the upper ocean to form cold wakes which reduces the air-sea fluxes. This is an example of negative feedback. By contrast, in regimes where the ocean mixed layers are deep (usually along the western part of the gyres), warm water advection by the nearly steady currents reduces the levels of turbulent mixing by shear instabilities. As these strong near-inertial shears are arrested, more heat and moisture transfers are available through the enthalpy fluxes (typically 1 to 1.5 kW m-2) into the hurricane boundary layer. When tropical cyclones move into favorable or neutral atmospheric conditions, tropical cyclones have a tendency to rapidly intensify as observed over the Gulf of Mexico during Isidore and Lili in 2002, Katrina, Rita and Wilma in 2005, Dean and Felix in 2007 in the Caribbean Sea, and Earl in 2010 just north of the Caribbean Islands. To predict these tropical cyclone deepening (as well as weakening) cycles, coupled models must have ocean models with realistic ocean conditions and accurate air-sea and vertical mixing parameterizations. Thus, to constrain these models, having complete 3-D ocean profiles juxtaposed with atmospheric profiler measurements prior, during and subsequent to passage is an absolute necessity framed within regional scale satellite derived fields.

  14. Tropical Cyclone Diurnal Cycle as Observed by TRMM

    NASA Technical Reports Server (NTRS)

    Leppert, Kenneth D., II; Cecil, D. J.

    2015-01-01

    Using infrared satellite data, previous work has shown a consistent diurnal cycle in the pattern of cold cloud tops around mature tropical cyclones. In particular, an increase in the coverage by cold cloud tops often occurs in the inner core of the storm around the time of sunset and subsequently propagates outward to several hundred kilometers over the course of the following day. This consistent cycle may have important implications for structure and intensity changes of tropical cyclones and the forecasting of such changes. Because infrared satellite measurements are primarily sensitive to cloud top, the goal of this study is to use passive and active microwave measurements from the Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI) and Precipitation Radar (PR), respectively, to examine and better understand the tropical cyclone diurnal cycle throughout a larger depth of the storm's clouds. The National Hurricane Center's best track dataset was used to extract all PR and TMI pixels within 1000 km of each tropical cyclone that occurred in the Atlantic basin between 1998-2011. Then the data was composited according to radius (100-km bins from 0-1000 km) and local standard time (LST; 3-hr bins). Specifically, PR composites involved finding the percentage of pixels with reflectivity greater than or equal to 20 dBZ at various heights (i.e., 2-14 km in increments of 2 km) as a function of radius and time. The 37- and 85- GHz TMI channels are especially sensitive to scattering by precipitation-sized ice in the mid to upper portions of clouds. Hence, the percentage of 37- and 85-GHz polarization corrected temperatures less than various thresholds were calculated using data from all storms as a function of radius and time. For 37 GHz, thresholds of 260 K, 265 K, 270 K, and 275 K were used, and for 85 GHz, thresholds of 200-270 K in increments of 10 K were utilized. Note that convection forced by the interactions of a tropical cyclone with land (e.g., due

  15. Do Speleothem Stable Isotope Records Contain Hidden Tropical Cyclone Histories? Exploring C-O Isotope Correlation Patterns for Indicators of Tropical Cyclone Masking

    NASA Astrophysics Data System (ADS)

    Frappier, A. E.; Rossington, C.

    2013-12-01

    The newly-described tropical cyclone masking effect on stable isotope paleohydrological signals in speleothem records arises from the intermittent delivery of large pulses of isotopically distinct tropical cyclone rain. Recent work shows that 18-O depleted tropical cyclone stormwater depresses the δ18O value of speleothem calcite for months to years following a tropical cyclone event, masking the background stable isotope signal of persistent climate variability. Periods of high local storm activity can lead to speleothem calcite paleohydrological signals with significant wet biases on interannual to decadal timescales. Because speleothem carbon isotope ratios are independent of tropical cyclone rainfall, tropical speleothems are known to exhibit moderate C-O isotope covariation over time, periods when C-O isotope covariation breaks down and δ18O values are low may provide a marker for times when tropical cyclone masking is important. If so, existing speleothem stable isotope records from tropical cyclone-prone regions may contain signatures of tropical cyclone masking in the temporal evolution of C-O isotope covariation patterns. We present results from an exploratory analysis of several published speleothem records that are candidates for containing tropical cyclone masking signals. For each speleothem, overall C-O isotope covariation coefficients were calculated, and transient covariation patterns were analyzed using a sliding correlation index, the Covariation of Stable Isotopes (CoSI) index, and Local Correlation (LoCo). Local tropical cyclone historical and paleotempest records are compared and a method is presented to test for the presence of tropical cyclone masking intervals. The implications for speleothem paleoclimatology and paleotempestology are discussed.

  16. Intensification of tropical cyclones in the GFS model

    NASA Astrophysics Data System (ADS)

    Marín, J. C.; Raymond, D. J.; Raga, G. B.

    2008-09-01

    Special forecasts from the Global Forecast System (GFS) model were used in this study to evaluate how the intensification process in a tropical cyclone is represented in this model. Several tropical cyclones that developed in 2005 were analyzed in terms of the storm-scale circulation rather than more traditional measures such as maximum wind or minimum central pressure. The primary balance governing the circulation in the planetary boundary layer is between the convergence of environmental vorticity, which tends to spin up the storm, and surface friction, which tends to spin it down. In addition, we employ recently developed ideas about the relationship between precipitation and the saturation fraction of the environment to understand the factors controlling mass, and hence vorticity convergence. The budget of moist entropy is central to this analysis. Two well-known governing factors for cyclone intensification emerge from this study; surface moist entropy fluxes, dependent in the model on sea surface temperature and cyclone-generated surface winds, and ventilation of the system by dry environmental air. Quantitative expressions for the role of these factors in cyclone intensification are presented in this paper.

  17. Intensification of tropical cyclones in the GFS model

    NASA Astrophysics Data System (ADS)

    Marín, J. C.; Raymond, D. J.; Raga, G. B.

    2009-02-01

    Special forecasts from the Global Forecast System (GFS) model were used in this study to evaluate how the intensification process in a tropical cyclone is represented in this model. Several tropical cyclones that developed in 2005 were analyzed in terms of the storm-scale circulation rather than more traditional measures such as maximum wind or minimum central pressure. The primary balance governing the circulation in the planetary boundary layer is between the convergence of environmental vorticity, which tends to spin up the storm, and surface friction, which tends to spin it down. In addition, we employ recently developed ideas about the relationship between precipitation and the saturation fraction of the environment to understand the factors controlling mass, and hence vorticity convergence. The budget of moist entropy is central to this analysis. Two well-known governing factors for cyclone intensification emerge from this study; surface moist entropy fluxes, dependent in the model on sea surface temperature and cyclone-generated surface winds, and ventilation of the system by dry environmental air. Quantitative expressions for the role of these factors in cyclone intensification are presented in this paper.

  18. Relation between tropical cyclone heat potential and cyclone intensity in the North Indian Ocean

    NASA Astrophysics Data System (ADS)

    Jangir, B.; Swain, D.; Udaya Bhaskar, T. V. S.

    2016-05-01

    Ocean Heat Content (OHC) plays a significant role in modulating the intensity of Tropical Cyclones (TC) in terms of the oceanic energy available to TCs. TC Heat Potential (TCHP), an estimate of OHC, is thus known to be a useful indicator of TC genesis and intensification. In the present study, we analyze the role of TCHP in intensification of TCs in the North Indian Ocean (NIO) through statistical comparisons between TCHP and Cyclone Intensities (CI). A total of 27 TCs (20 in the Bay of Bengal, and 7 in the Arabian Sea) during the period 2005-2012 have been analyzed using TCHP data from Global Ocean Data Assimilation System (GODAS) model of Indian National Center for Ocean Information Services and cyclone best track data from India Meteorological Department. Out of the 27 cyclones analyzed, 58% (86%) in the Bay (Arabian Sea) have negative correlation and 42% (14%) cyclones have positive correlation between CI and TCHP. On the whole, more than 60% cyclones in the NIO show negative correlations between CI and TCHP. The negative percentage further increases for TCHP leading CI by 24 and 48 hours. Similar trend is also seen with satellite derived TCHP data obtained from National Remote Sensing Center and TC best track data from Joint Typhoon Warming Centre. Hence, it is postulated that TCHP alone need not be the only significant oceanographic parameter, apart from sea surface temperature, responsible for intensification and propagation of TCs in the NIO.

  19. Modeling Tropical Cyclone induced inland flooding for Houston metropolitan area

    NASA Astrophysics Data System (ADS)

    Zhu, L.

    2011-12-01

    Tropical cyclones are an important source of extreme precipitation and they have caused destructive inland floods in Texas. The Houston metropolitan area is a highly populated region with rapid economic development. The Bayou River basin was selected as the study area because it covers most of Houston. This study will employ HEC-HMS (a hydrological model) simulate the flood discharge from tropical storm Alison in 2001. The simulated discharge will be compared with observed discharge values for model adjustment and calibration. An iterative process will be used to calibrate the model. Then the flood discharge of another extreme precipitation event (Hurricane Ike) will be calculated from the fitted HEC model. Modeled discharge from both events will be used as inputs for HEC-RAS (a hydraulic model) to generate regional inundation maps. The purposes of this study are: (1) to understand how an urbanized hydrological system in Texas reacts to extreme precipitation brought by Tropical Cyclones, and (2) to construct a reliable model of inland flooding for future applications. Questions will be answered by this study are: What are the similarities and differences in flooding caused by two recent tropical storms that have affected the Houston metro area? Which factor plays a more important role in determining the TC floods intensity, variations in precipitation or changes in land use? Key words: Tropical Cyclone, Hydrological Model, Floods, Houston

  20. On the violation of gradient wind balance at the top of tropical cyclones

    NASA Astrophysics Data System (ADS)

    Cohen, Yair; Harnik, Nili; Heifetz, Eyal; Nolan, David S.; Tao, Dandan; Zhang, Fuqing

    2017-08-01

    The existence of physical solutions for the gradient wind balance is examined at the top of 12 simulated tropical cyclones. The pressure field at the top of these storms, which depends on the vertically integrated effect of the warm core and the near surface low, is found to violate the gradient wind balance—termed here as a state of nonbalance. Using a toy model, it is shown that slight changes in the relative location and relative widths of the warm core drastically increase the isobaric curvature at the upper level pressure maps leading to nonbalance. While idealized storms return to balance within several days, simulations of real-world tropical cyclones retain a considerable degree of nonbalance throughout the model integration. Comparing mean and maximum values of different storms shows that peak nonbalance correlates with either peak intensity or intensification, implying the possible importance of nonbalance at upper levels for the near surface winds.

  1. Tree-ring isotope records of tropical cyclone activity.

    PubMed

    Miller, Dana L; Mora, Claudia I; Grissino-Mayer, Henri D; Mock, Cary J; Uhle, Maria E; Sharp, Zachary

    2006-09-26

    The destruction wrought by North Atlantic hurricanes in 2004 and 2005 dramatically emphasizes the need for better understanding of tropical cyclone activity apart from the records provided by meteorological data and historical documentation. We present a 220-year record of oxygen isotope values of alpha-cellulose in longleaf pine tree rings that preserves anomalously low isotope values in the latewood portion of the ring in years corresponding with known 19th and 20th century landfalling/near-coastal tropical storms and hurricanes. Our results suggest the potential for a tree-ring oxygen isotope proxy record of tropical cyclone occurrence extending back many centuries based on remnant pine wood from protected areas in the southeastern U.S.

  2. Tree-ring isotope records of tropical cyclone activity

    PubMed Central

    Miller, Dana L.; Mora, Claudia I.; Grissino-Mayer, Henri D.; Mock, Cary J.; Uhle, Maria E.; Sharp, Zachary

    2006-01-01

    The destruction wrought by North Atlantic hurricanes in 2004 and 2005 dramatically emphasizes the need for better understanding of tropical cyclone activity apart from the records provided by meteorological data and historical documentation. We present a 220-year record of oxygen isotope values of α-cellulose in longleaf pine tree rings that preserves anomalously low isotope values in the latewood portion of the ring in years corresponding with known 19th and 20th century landfalling/near-coastal tropical storms and hurricanes. Our results suggest the potential for a tree-ring oxygen isotope proxy record of tropical cyclone occurrence extending back many centuries based on remnant pine wood from protected areas in the southeastern U.S. PMID:16984996

  3. Genesis of tropical cyclone Nargis revealed by multiple satellite observations

    NASA Astrophysics Data System (ADS)

    Kikuchi, Kazuyoshi; Wang, Bin; Fudeyasu, Hironori

    2009-03-01

    Tropical cyclone (TC) Nargis recently battered Myanmar on May 2 2008 is one of the most deadly tropical storms in history. Nargis was initiated by an abnormally strong intraseasonal westerly event associated with Madden-Julian oscillation (MJO) in the eastern Indian Ocean. An incipient cyclonic disturbance emerged as an emanation of Rossby wave-induced vortex when the intraseasonal convective anomaly reached the Maritime Continent. The northeastward movement of MJO convection facilitated further development of the disturbance. The incipient disturbance became a tropical disturbance (TD) with a central warm-core structure on April 26. The further development from the TD to TC formation on April 28 is characterized by two distinctive stages: a radial contraction followed by a rapid intensification. The processes responsible for contraction and rapid intensification are discussed by diagnosis of multiple satellite data. This proposed new scenario is instrumental for understanding how a major TC develops in the northern Indian Ocean.

  4. Tropical Cyclones in the GISS ModelE2

    NASA Technical Reports Server (NTRS)

    Camargo, Suzana J.; Sobel, Adam H.; Del Genio, Anthony; Jonas, Jeffrey A.; Kelley, Maxwell; Lu, Yun; Shaevitz, Daniel; Henderson, Naomi

    2016-01-01

    The authors describe the characteristics of tropical cyclone (TC) activity in the GISS general circulation ModelE2 with a horizontal resolution 1deg x 1deg. Four model simulations are analyzed. In the first, the model is forced with sea surface temperature (SST) from the recent historical climatology. The other three have different idealized climate change simulations, namely (1) a uniform increase of SST by 2 deg., (2) doubling of the CO2 concentration and (3) a combination of the two. These simulations were performed as part of the US Climate Variability and Predictability Program Hurricane Working Group. Diagnostics of standard measures of TC activity are computed from the recent historical climatological SST simulation and compared with the same measures computed from observations. The changes in TC activity in the three idealized climate change simulations, by comparison with that in the historical climatological SST simulation, are also described. Similar to previous results in the literature, the changes in TC frequency in the simulation with a doubling CO2 and an increase in SST are approximately the linear sum of the TC frequency in the other two simulations. However, in contrast with previous results, in these simulations the effects of CO2 and SST on TC frequency oppose each other. Large-scale environmental variables associated with TC activity are then analyzed for the present and future simulations. Model biases in the large-scale fields are identified through a comparison with ERA-Interim reanalysis. Changes in the environmental fields in the future climate simulations are shown and their association with changes in TC activity discussed.

  5. Tropical Cyclones in the GISS ModelE2

    NASA Technical Reports Server (NTRS)

    Camargo, Suzana J.; Sobel, Adam H.; Del Genio, Anthony; Jonas, Jeffrey A.; Kelley, Maxwell; Lu, Yun; Shaevitz, Daniel; Henderson, Naomi

    2016-01-01

    The authors describe the characteristics of tropical cyclone (TC) activity in the GISS general circulation ModelE2 with a horizontal resolution 1deg x 1deg. Four model simulations are analyzed. In the first, the model is forced with sea surface temperature (SST) from the recent historical climatology. The other three have different idealized climate change simulations, namely (1) a uniform increase of SST by 2 deg., (2) doubling of the CO2 concentration and (3) a combination of the two. These simulations were performed as part of the US Climate Variability and Predictability Program Hurricane Working Group. Diagnostics of standard measures of TC activity are computed from the recent historical climatological SST simulation and compared with the same measures computed from observations. The changes in TC activity in the three idealized climate change simulations, by comparison with that in the historical climatological SST simulation, are also described. Similar to previous results in the literature, the changes in TC frequency in the simulation with a doubling CO2 and an increase in SST are approximately the linear sum of the TC frequency in the other two simulations. However, in contrast with previous results, in these simulations the effects of CO2 and SST on TC frequency oppose each other. Large-scale environmental variables associated with TC activity are then analyzed for the present and future simulations. Model biases in the large-scale fields are identified through a comparison with ERA-Interim reanalysis. Changes in the environmental fields in the future climate simulations are shown and their association with changes in TC activity discussed.

  6. Tropical and Extratropical Cyclone Damages under Climate Change

    NASA Astrophysics Data System (ADS)

    Ranson, M.; Kousky, C.; Ruth, M.; Jantarasami, L.; Crimmins, A.; Tarquinio, L.

    2014-12-01

    This paper provides the first quantitative synthesis of the rapidly growing literature on future tropical and extratropical cyclone losses under climate change. We estimate a probability distribution for the predicted impact of changes in global surface air temperatures on future storm damages, using an ensemble of 296 estimates of the temperature-damage relationship from twenty studies. Our analysis produces three main empirical results. First, we find strong but not conclusive support for the hypothesis that climate change will cause damages from tropical cyclones and wind storms to increase, with most models (84 and 92 percent, respectively) predicting higher future storm damages due to climate change. Second, there is substantial variation in projected changes in losses across regions. Potential changes in damages are greatest in the North Atlantic basin, where the multi-model average predicts that a 2.5°C increase in global surface air temperature would cause hurricane damages to increase by 62 percent. The ensemble predictions for Western North Pacific tropical cyclones and European wind storms (extratropical cyclones) are approximately one third of that magnitude. Finally, our analysis shows that existing models of storm damages under climate change generate a wide range of predictions, ranging from moderate decreases to very large increases in losses.

  7. The effect of tropical cyclones (typhoons) on emergency department visits.

    PubMed

    Lin, Chien-Hao; Hou, Sen-Kuang; Shih, Frank Fuh-Yuan; Su, Syi

    2013-09-01

    Case reports have indicated that a tropical cyclone may increase Emergency Department (ED) visits significantly. To examine emergency health care demands across a series of tropical cyclones, and to build a predictive model to analyze a cyclone's potential effect. This was an observational non-concurrent prospective study performed in Taiwan. Twenty hospitals were included. The number of daily ED visits in each hospital was our primary end point, and data were retrieved from the database provided by the National Health Insurance Research Database. Our study examined the period from 2000 to 2008. A total of 22 tropical cyclones (typhoons) that had passed over eastern Taiwan and covered the area under study were included. Multiple linear regression time-series models were employed to estimate the effects of "days since typhoon landfall" and various characteristics of the typhoons on the end point of daily ED visits to each hospital. The final multiple linear regression time-series model showed that the number of daily ED visits increased in areas where a strong typhoon had landed directly, with the increase being evident during the first 2 days since landfall. Our model also indicated that the three most important variables to predict a change in the pattern of daily ED visits were intensity of typhoon, simultaneous heavy rain, and direct landfall. During tropical cyclones, emergency services were under increased demand in selected time periods and areas. Health care authorities should collect information to build local models to optimize their resources allocation in preparation. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

  8. Clustering of tropical cyclones in the North Atlantic

    NASA Astrophysics Data System (ADS)

    Vitolo, Renato; Stephenson, David; Cook, Ian

    2010-05-01

    We investigate the spatial dependence of and the large-scale atmospheric and climatic effects on the clustering of tropical cyclones in the North Atlantic Ocean. Tropical cyclone tracks from the HURDAT database are examined. We study the transit of tropical cyclones near points belonging to a grid covering the North Atlantic Ocean. Clustering is characterized by the dispersion (ratio of the variance and the mean) of the yearly counts of cyclone transits at distance less than a radius R from the gridpoints. Coherent patches of overdispersion are found for large radii (R>=300km) in the main development region, in the central North Atlantic, off the Mexican coast in the Gulf of Mexico and in the Caribbean sea. Transits of tropical cyclones with intense windspeeds (>60kt) are overdispersed in smaller regions. Patches of overdispersion occur in the central North Atlantic and in a region surrounding the souther coast of Florida, the western coast of Cuba and the coast of Belize. The influence of large-scale atmospheric and climatic processes is analysed by Poisson regression with a time-varying rate that depends on indices for the Atlantic Multidecadal Oscillation (AMO), the North Atlantic Oscillation (NAO) and the Southern Oscillation (SO). A clear-cut signal is found at the largest spatial scales (R>=300km). The AMO has positive effects on the local transit rate in a very large region of the North Atlantic, around the main development region and Caribbean Sea. Positive effects are found for the NAO around Cuba and the Caribbean. Negative (though small) effects are found for the SOI in the Caribbean and the Gulf of Mexico.

  9. The Relationship Between Tropical Cyclone Frequency and 'Climate Change'

    NASA Astrophysics Data System (ADS)

    Bolton, M.; Mogil, M.

    2013-12-01

    Please note: there have been minor updates to this work since the main author, Matt Bolton, graduated high school, but the majority of the research was compiled by him while he was a high school junior in 2011. Abstract: In recent years, there has been a growing trend by many, in the meteorological community (media and scientist) to predict expected seasonal tropical cyclone frequency in the Atlantic and Pacific Basins. Typically, the numbers are related to seasonal averages. However, these predictions often show a large positive bias (i.e., there are more years in which the expected number of storms exceeds or far exceeds average). Further, observed numbers often come close to bearing out the forecasts (actually a good thing). From a public perspective (and based on extrapolations performed by media and some scientific groups), this peaking of Atlantic tropical cyclone activity is observed globally. In an attempt to determine if such a global trend exists, we set out to collect data from weather agencies around the world and present it in a way that was as unbiased as possible. While there were inconsistencies across the various datasets, especially in regard to wind data, we were still able to construct a realistic global cyclone database. We have concluded that high activity levels in one basin are often balanced by areas of low activity in others. The Atlantic - Eastern Pacific couplet is one such example. This paper will serve as an update to our previous 2011 paper, which introduced our efforts. At that time, we found, on average, 70 named tropical cyclones worldwide. In both this and our original study, we did not address the issue of naming short-lived tropical systems, which was found to be inconsistent across worldwide ocean basins. Our results suggest, that from a global climate change perspective, a growing NUMBER of tropical cyclones is NOT being observed. In the current iteration of our study, we are examining, at least preliminarily, global

  10. Dynamics of vortex Rossby waves in tropical cyclones

    NASA Astrophysics Data System (ADS)

    Nikitina, Lidia

    This thesis describes an analytical study of vortex Rossby waves in tropical cyclones. Observational analyses of hurricanes in the tropical atmosphere indicate the existence of spiral rainbands which propagate outwards from the eye and affect the structure and intensity of the hurricane. These disturbances may be described as vortex Rossby waves. The aim of this research is to study the propagation of vortex Rossby waves in tropical cyclones and wave-mean-flow interactions near the critical radius where the mean flow angular velocity matches the phase speed of the waves. Depending on the wave magnitude, the problem can be linear or nonlinear. Analytical techniques including Laplace transforms, multiple scaling and asymptotic expansions are used to obtain approximate solutions of the governing linear and nonlinear equations. In this study we carry out asymptotic analyses to examine the evolution of the interactions near the critical radius in some two-dimensional configurations on an f-plane and a beta-plane. The results are used to explain some features of the tropical cyclone's development, namely, the change of angular wind in the critical layer, the secondary eyewall formation and the eyewall dynamics.

  11. Tropical Cyclone Monty Strikes Western Australia

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Multi-angle Imaging SpectroRadiometer (MISR) acquired these natural color images and cloud top height measurements for Monty before and after the storm made landfall over the remote Pilbara region of Western Australia, on February 29 and March 2, 2004 (shown as the left and right-hand image sets, respectively). On February 29, Monty was upgraded to category 4 cyclone status. After traveling inland about 300 kilometers to the south, the cyclonic circulation had decayed considerably, although category 3 force winds were reported on the ground. Some parts of the drought-affected Pilbara region received more than 300 millimeters of rainfall, and serious and extensive flooding has occurred.

    The natural color images cover much of the same area, although the right-hand panels are offset slightly to the east. Automated stereoscopic processing of data from multiple MISR cameras was utilized to produce the cloud-top height fields. The distinctive spatial patterns of the clouds provide the necessary contrast to enable automated feature matching between images acquired at different view angles. The height retrievals are at this stage uncorrected for the effects of the high winds associated with cyclone rotation. Areas where heights could not be retrieved are shown in dark gray.

    The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbits 22335 and 22364. The panels cover an area of about 380 kilometers x 985 kilometers, and utilize data from blocks 105 to 111 within World Reference System-2 paths 115 and 113.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the

  12. Contribution of Tropical Cyclones to the North Pacific Climatological Rainfall as Observed from Satellites

    NASA Technical Reports Server (NTRS)

    Rodgers, Edward B.; Adler, Robert F.; Pierce, Harold F.

    1997-01-01

    Tropical cyclone monthly rainfall amounts are estimated from passive microwave satellite observations for an eleven year period. These satellite-derived rainfall amounts are used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and inter-annual distribution of the North Pacific Ocean total rainfall during June-November when tropical cyclones are most important. To estimate these tropical cyclone rainfall amounts, mean monthly rain rates are derived from passive microwave satellite observations within 444 km radius of the center of those North Pacific tropical cyclones that reached storm stage and greater. These rain rate observations are converted to monthly rainfall amounts and then compared to those for non-tropical cyclone systems. The main results of this study indicate that: 1) tropical cyclones contribute 7% of the rainfall to the entire domain of the North Pacific during the tropical cyclone season and 12%, 3%, and 4% when the study area is limited to, respectively, the western, central, and eastern third of the ocean; 2) the maxima in tropical cyclone rainfall are poleward (5 deg to 10 deg latitude depending on longitude) of the maxima in non-tropical cyclone rainfall; 3) tropical cyclones contribute a maximum of 30% northeast of the Philippine Islands and 40% of the lower Baja California coast; 4) in the western North Pacific, the tropical cyclone rainfall lags the total rainfall by approximately two months and shows seasonal latitudinal variation following the ITCZ; and 5) in general, tropical cyclone rainfall is enhanced during the El Nino years by warm SSTs in the eastern North Pacific and by the monsoon trough in the western and central North Pacific.

  13. Coastal Hazard due to Tropical Cyclones in Mexico

    NASA Astrophysics Data System (ADS)

    Silva-Casarin, R.; Mendoza-Baldwin, E.; Marino-Tapia, I.; Enriquez, C.; Ruiz, G.; Escalante-MAncera, E.; Ruíz-Rentería, F.

    2013-05-01

    The Mexican coast is hit every year by at least 3 cyclones and it is affected for nearly 59 hours a year on average; this induces undesirable consequences, such as coastal erosion and flooding. To evaluate the hazard to which the coastal zone is exposes, a historical characterization of atmospheric conditions (surface winds and pressure conditions of the storms), waves (wave heights and their associated wave periods) and flooding levels due to tropical storms for more than 60 years is presented. The atmospheric and wave conditions were evaluated using a modification of the original parametric Hydromet-Rankin Vortex Model by Bretschneider (1990) and Holland (1980) as presented by Silva, et al. (2002). The flooding levels caused by hurricanes were estimated using a two-dimensional, vertically averaged finite volume model to evaluate the storm surge, Posada et al. (2008). The cyclone model was compared to the data series of 29 cyclones recorded by buoys of the National Data Buoy Center-NOAA and some data recorded in shallow waters near Cancun, Mexico and the flooding model was compared with observed data from Cancun, Mexico; both models gave good results. For the extreme analyses of wind, wave heights and maximum flooding levels on the Mexican coasts, maps of the scale and location parameters used in the Weibull cumulative distribution function and numerical results for different return periods are provided. The historical occurrence of tropical storms is also revised as some studies indicate that the average intensity of tropical cyclones is increasing; no definite trends pointing to an increase in storm frequency or intensity were found. What was in fact found is that although there are more cyclones in the Pacific Ocean and these persist longer, the intensity of the cyclones in the Atlantic Ocean is greater affecting. In any case, the strong necessity of avoiding storm induced coastal damage (erosion and flooding) is reflected in numerous works, such as this one

  14. Variable-resolution frameworks for the simulation of tropical cyclones in global atmospheric general circulation models

    NASA Astrophysics Data System (ADS)

    Zarzycki, Colin

    The ability of atmospheric General Circulation Models (GCMs) to resolve tropical cyclones in the climate system has traditionally been difficult. The challenges include adequately capturing storms which are small in size relative to model grids and the fact that key thermodynamic processes require a significant level of parameterization. At traditional GCM grid spacings of 50-300 km tropical cyclones are severely under-resolved, if not completely unresolved. This thesis explores a variable-resolution global model approach that allows for high spatial resolutions in areas of interest, such as low-latitude ocean basins where tropical cyclogenesis occurs. Such GCM designs with multi-resolution meshes serve to bridge the gap between globally-uniform grids and limited area models and have the potential to become a future tool for regional climate assessments. A statically-nested, variable-resolution option has recently been introduced into the Department of Energy/National Center for Atmospheric Research (DoE/NCAR) Community Atmosphere Model's (CAM) Spectral Element (SE) dynamical core. Using an idealized tropical cyclone test, variable-resolution meshes are shown to significantly lessen computational requirements in regional GCM studies. Furthermore, the tropical cyclone simulations are free of spurious numerical errors at the resolution interfaces. Utilizing aquaplanet simulations as an intermediate test between idealized simulations and fully-coupled climate model runs, climate statistics within refined patches are shown to be well-matched to globally-uniform simulations of the same grid spacing. Facets of the CAM version 4 (CAM4) subgrid physical parameterizations are likely too scale sensitive for variable-resolution applications, but the newer CAM5 package is vastly improved in performance at multiple grid spacings. Multi-decadal simulations following 'Atmospheric Model Intercomparison Project' protocols have been conducted with variable-resolution grids. Climate

  15. High-frequency Oscillations in Eyewalls of Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Li, Weibiao; Chen, Shumin

    2017-04-01

    High-frequency oscillations, with periods of about 2 hours, are first identified by applying wavelet analysis to observed minutely wind speeds around the eye and eyewall of tropical cyclones (TCs). Analysis of a model simulation of Typhoon Hagupit (2008) shows that the oscillations also occur in the intensity of TC, vertical motion, convergence activity and air density around the eyewall. Sequences of oscillations in these variables follow a certain order. In a typical cycle, the drop of density in the planetary boundary layer (PBL) is followed by an increase in the inward radial wind; this enhanced frictional convergence causes increase in density, followed by a decrease in the inward radial wind. The increase in convergence in the PBL causes increase of updraft at the top of the PBL, followed by high vertical velocity at high altitude of 8-10 km, then the increase of the maximum wind speed, and vice versa. Key words: tropical cyclone, high-frequency oscillations, eyewall, intensity

  16. Monitoring tropical cyclone evolution with NOAA satellite microwave observations

    NASA Technical Reports Server (NTRS)

    Velden, C.; Smith, W. L.

    1983-01-01

    NOAA satellite microwave soundings, which penetrate high clouds, delineate the development and dissipation of the upper tropospheric warm core associated with a tropical cyclone. The storm's 'core" may be detected from microwave imagery. Vertical cross sections reveal the intensification of the upper tropospheric warm core as the storm develops, and the downward propagation of the warm core as the storm dissipates. Excellent correlation is found between the horizontal Laplacian of an upper tropospheric temperature field and the intensity of the storm, as categorized by its surface central pressure and maximum sustained wind speed at the eye wall. The microwave monitoring of tropical cyclones is achieved in real time at the University of Wisconsin's Space Science and Engineering Center through high-speed teleconnections to direct readout receiving systems at Wallops Island, Virginia and Redwood City, California.

  17. How Does Intertropical Convergence Zone Variation Impact on Tropical Cyclone in the Northern Hemisphere?

    NASA Astrophysics Data System (ADS)

    Ma, Liping; Williams, Richard

    2017-04-01

    Enhanced sea surface temperature is expected to be favourable for more tropical cyclone formation. However, a surprising result emerges from the analysis of the frequency of tropical cyclones in the global tropical oceans in the northern hemisphere. The frequency of tropical cyclones positively correlates with a strengthening and northward movement of the Intertropical Convergence Zone (ITCZ hereafter). There is a different regional character for the tropical cyclones activity: in the Western North Pacific, the number of tropical cyclones has been decreasing since 1960s, whereas in the Eastern North Pacific and North Atlantic, the number of tropical cyclones has been increasing since 1949 and 1984 respectively. Most of the tropical cyclones in the tropical oceans are generated within the ITCZ (called the monsoon trough in the Western North Pacific, and the easterly wave in the Eastern North Pacific and North Atlantic). At the same time, there are changes in the strength and position of the ITCZ. In the Western North Pacific, ITCZ strength has been weakening and its position has been moving equatorward since the 1960s when the tropical cyclones frequency decreased. In the Eastern North Pacific, the ITCZ has been strengthening and moving northward where the tropical cyclone frequency has been increasing since 1949. In North Atlantic, since the mid-1980s, the ITCZ has been strengthening and moving northward and the tropical cyclone numbers have been increasing uniformly since then. To understand the differing regional response, the ITCZ may be viewed as a planetary wave undulating around the planet along the tropics. The trough phase is correlated with where the tropical cyclone numbers reduce, such as in the Western North Pacific since 1960s; conversely, its peak phase in the tropical oceans is where the frequency of tropical cyclones increases, such as in the tropical Eastern North Pacific since 1949 and North Atlantic since 1984 In conclusion, this research reveals

  18. Diabatic potential vorticity anomalies in extratropical cyclones in idealized simulations of changed climates

    NASA Astrophysics Data System (ADS)

    Pfahl, Stephan; Büeler, Dominik; O'Gorman, Paul; Singh, Martin

    2017-04-01

    The response of extratropical cyclone intensity to climate warming is governed by several partly opposing mechanisms, whose representation in models is associated with substantial uncertainties. Here the role of one specific mechanism, the contribution of latent heat release due to cloud formation to cyclone intensification, is investigated with the help of idealized climate model simulations in an aquaplanet setup and making use of the potential vorticity (PV) framework. A simple diagnostic theory is developed that quantifies the contribution of latent heating to PV anomalies within cyclones. The theory is able to explain the increase of lower-tropospheric PV in intense cyclones with climate warming over a wide range of simulated climates. As this rise in PV goes along with an increase also in cyclone intensity (measured in terms of near-surface relative vorticity), the theory provides a useful framework to understand the increasing importance of diabatic processes for cyclone intensification in warmer and more humid climates.

  19. Role of Vortex Rossby Waves on Tropical Cyclone Intensity

    DTIC Science & Technology

    2016-06-07

    project is to improve the prediction of tropical cyclone (TC) genesis and intensity changes through improved understanding of the fundamental mechanisms...involved. Accurate prediction of TC intensity changes is critical to Navy mission and civilian activities. Significant gains have been made in the...TC track prediction over the past three decades. The intensity forecast, however, has shown very little improvement during the same period. A main

  20. Numerical Experiments of the Diurnal Cycle of Axisymmetric Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Navarro, E. L.; Hakim, G. J.

    2015-12-01

    Recent observational and modeling studies have shown that the diurnal cycle of radiation may be fundamentally linked to structural changes in the lifetime of a tropical cyclone. While these studies suggest that an underlying mechanism within the storm may exist, the dynamics for this response are still largely unexplained. Previous modeling studies were limited due to model configuration (e.g., initial and boundary conditions) as well as to radiative parameterization schemes. In this presentation, two new investigations are discussed to reexamine the role of the daily cycle of radiation on axisymmetric hurricane structure. In the first study, a tropical cyclone lasting 324 days is generated in Cloud Model 1 (CM1, see Bryan and Rotunno 2009) to quantify a tropical cyclone diurnal signal. A coherent response is observed in the temperature, wind, and cloud ice fields that accounts for up to a third of the overall variance. Composite analysis of each hour of the day shows a diurnal cycle in the storm intensity that, relative to the mean, intensifies in the early hours of the morning and is consistent with observational studies. Examination of the radial and vertical wind suggests two distinct circulations forced by the diurnal cycle: (1) a radiatively-driven circulation in the outflow layer due to absorption of solar radiation, and (2) a convectively-driven circulation within the storm due to latent heating. These responses are coupled and are periodic with respect to the diurnal cycle. In the second study, following the method of Pendergrass and Willoughby (2009) and Willoughby (2009), hypothesis tests using various prescribed, periodic heating distributions are performed to examine the dynamical response of the storm to radiation. Results reveal significant changes to the secondary-circulation structure of the storm, as well as to the intensification of the primary vortex. Sensitivity to the chosen heating distribution as well as to the initial vortex are discussed

  1. Initialization of Tropical Cyclone Structure for Operational Application

    DTIC Science & Technology

    2013-04-30

    656-4704, fax: (831) 656-4769, e-mail: melinda.peng@nrlmry.navy.mil Award Number: N000141010774 Final Report (5/1/2010- 4 /30/2013) LONG-TERM GOAL...controlled by environmental absolute angular momentum. 4 . Evaluation of multiple TC dynamics initialization schemes using COAMPS-TC Three different...Li , and M.-Y. Lee, 2011: Impacts of Central Pacific and Eastern Pacific El Ninos on tropical cyclone tracks over the western North Pacific

  2. Remotely Sensed Tropical Cyclone Structure/Intensity Changes

    DTIC Science & Technology

    2016-06-07

    two satellite platforms that carry passive microwave sensors in polar orbit; a) the Defense Meteorological Satellite Program (DMSP) and its Special...collected, though the Western Pacific season has not been normal. Chris Velden from the Cooperative Institute for Meteorological Satellite Studies (CIMSS...May, J. Sandidge, R. Holyer, M.J. Helveston, 1998, SSM/I-based tropical cyclone structural observations, AMS 9th Conference on Satellite Meteorology

  3. Design Considerations for an Advanced Tropical Cyclone Model.

    DTIC Science & Technology

    1985-10-01

    Naval Research Laboratory, S. Chang; National Hurricane Center (NHC), A. Pike; National Meteorological Center (NMC), M.. Mathur; and Colorado State...have an immediate positive impact on the accuracy of tropical cyclone track predictions. The omega dropwinsonde (O0W) program at the Hurricane Research...Division (HRD/NOAA) has successfully supplied data in real time around Atlantic hurricanes on several occasions (Burpee et al., 1984). When two

  4. Adopting Model Uncertainties for Tropical Cyclone Intensity Prediction

    NASA Astrophysics Data System (ADS)

    Rios Berrios, R.; Vukicevic, T.

    2012-12-01

    Tropical cyclone (TC) intensity prediction remains highly uncertain, despite the current efforts in improving the performance of numerical prediction models. This uncertainty has been attributed to many factors, one of them being the poor representations of physical processes within the models. Particularly, TC intensity predictions are sensitive to the choice of the physical parameterizations that represent small-scale processes that would otherwise not be resolved by the models, such as cloud microphysics, planetary boundary layer processes and turbulence. In order to better understand which set of parameterizations should be used to improve TC intensity forecasts, the Generic Inversion by Transfer Function Analysis (GITFA) is introduced in this study. The method produces a joint probability density function (PDF) of inverse estimation solution for a selected set of parameters given the forecast model and observations with their associated errors. This PDF in the parameter space is non-Gaussian for the nonlinear models and provides information about likelihood of the joint values of the parameters that would result in the model forecast within a given range of the uncertainty in the observation space. The PDF of the inverse estimate defines the optimal, mutually correlated ensemble of parameter values. In this study, two physical parameterizations from an axisymmetric model were perturbed to produce different idealized TCs simulations. Results from those simulations were used to form the transfer functions for GITFA to obtain the inverse solutions. Preliminary results show that when the observation is a point within the TC field, such as the maximum wind speed, the optimal range of parameters is poorly constrained. On the other hand, when an entire kinematic field is observed, the optimal parameters can be constrained to a subset of joint range of values. The results suggest that an ensemble of physical parameterizations should be employed to improve TC intensity

  5. On the role of surface friction in tropical cyclone intensification

    NASA Astrophysics Data System (ADS)

    Wang, Yuqing

    2017-04-01

    Recent studies have debated on whether surface friction is positive or negative to tropical cyclone intensification in the view on angular momentum budget. That means whether the frictionally induced inward angular momentum transport can overcome the loss of angular momentum to the surface due to surface friction itself. Although this issue is still under debate, this study investigates another implicit dynamical effect, which modifies the radial location and strength of eyewall convection. We found that moderate surface friction is necessary for rapid intensity of tropical cyclones. This is demonstrated first by a simple coupled dynamical system that couples a multi-level boundary layer model and a shallow water equation model above with mass source parameterized by mass flux from the boundary layer model below, and then by a full physics model. The results show that surface friction leads to the inward penetration of inflow under the eyewall, shift the boundary layer mass convergence slightly inside the radius of maximum wind, and enhance the upward mass flux, and thus diabatic heating in the eyewall and intensification rate of a TC. This intensification process is different from the direct angular momentum budget previously used to explain the role of surface friction in tropical cyclone intensification.

  6. Hindcasts of Integrated Kinetic Energy in North Atlantic Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Kozar, Michael; Misra, Vasubandhu

    2015-04-01

    Integrated kinetic energy (IKE) is a recently developed metric that evaluates the destructive potential of a tropical cyclone by assessing the size and strength of its wind field. Despite the potential usefulness of the IKE metric, there are few, if any, operational tools that are specifically designed to forecast IKE in real-time. Therefore, a system of artificial neural networks is created to produce deterministic and probabilistic projections of IKE in North Atlantic tropical cyclones out to 72 hours from a series of relevant environmental and storm specific normalized input parameters. In an effort to assess its real-time skill, this IKE forecasting system is run in a mock-operational mode for the 1990 to 2011 North Atlantic hurricane seasons. Hindcasts of IKE are produced in this manner by running the neural networks with hindcasted input parameters from NOAA's second generation Global Ensemble Forecasting System reforecast dataset. Ultimately, the results of the hindcast exercises indicate that the neural network system is capable of skillfully forecasting IKE in an operational setting at a level significantly higher than climatology and persistence. Ultimately, forecasts of IKE from these neural networks could potentially be an asset for operational meteorologists that would complement existing forecast tools in an effort to better assess the damage potential of landfalling tropical cyclones, particularly with regards to storm surge damage.

  7. Tropical Cyclone - Equatorial Ionosphere Coupling: A Statistical Study

    NASA Astrophysics Data System (ADS)

    Bhagavathiammal, G. J.

    2016-07-01

    This paper describes the equatorial ionosphere response to tropical cyclone events which was observed over the Indian Ocean. This statistical study tries to reveal the possible Tropical Cyclone (TC) - Ionosphere coupling. Tropical cyclone track and data can be obtained from the India Meteorological Department, New Delhi. Digisonde/Ionosonde data for the equatorial latitudes can be obtained from Global Ionospheric Radio Observatory. It is believed that TC induced convection as the driving agent for the increased gravity wave activity in the lower atmosphere and these propagating gravity waves deposit their energy and momentum into the upper atmosphere as Travelling Ionospheric Disturbances (TIDs). The convective regions are identified with the help of Outgoing Long wave radiation (OLR) data from NOAA Climate Data Center/ Precipitation data from TRMM Statellite. The variability of ionospheric parameter like Total Electron Content (TEC), foF2, h'F2 and Drift velocity are examined during TC periods. This study will report the possibility of TC-Ionosphere Coupling in equatorial atmosphere.

  8. Tropical cyclone Pam coastal impact survey in Vanuatu

    NASA Astrophysics Data System (ADS)

    Fritz, H. M.; Pilarczyk, J.; Kosciuch, T. J.; Hong, I.; Rarai, A.; Harrison, M. J.; Jockley, F. R.; Horton, B.

    2015-12-01

    Severe tropical cyclone Pam (Cat. 5, SSHS) crossed the Vanuatu archipelago with sustained winds of 270 km/h on March 13 and 14, 2015 and made landfall on Erromango. Pam caused the worst natural disaster in Vanuatu's recorded history since severe tropical cyclone Uma in 1987. Eleven fatalities were directly attributed to cyclone Pam and mostly due to lack of shelter from airborne debris. On March 6 Pam formed east of the Santa Cruz Islands and intensified while tracking southward along Vanuatu severely affecting the Shefa and Tafea Provinces. An international storm surge reconnaissance team was deployed to Vanuatu from June 3 to 17, 2015 to complement earlier local surveys. Cyclone Pam struck a remote island archipelago particularly vulnerable to the combined cyclonic multi-hazards encompassing extreme wind gusts, massive rainfall and coastal flooding due to a combination of storm surge and storm wave impacts. The team surveyed coastal villages on Epi, the Shepherd Islands (Tongoa and Mataso), Efate (including Lelepa), Erromango, and Tanna. The survey spanned 320 km parallel to the cyclone track between Epi and Tanna encompassing more than 45 sites including the hardest hit settlements. Coastal flooding profiles were surveyed from the shoreline to the limit of inundation. Maximum coastal flood elevations and overland flow depths were measured based on water marks on buildings, scars on trees, rafted debris and corroborated with eyewitness accounts. We surveyed 91 high water marks with characteristic coastal flood levels in the 3 to 7 m range and composed of storm surge with superimposed storm waves. Inundation distances were mostly limited to a few hundred meters. Coral boulders of more than 1 m diameter were measured on Erromango and sediment samples were collected at key sites across the archipelago. Infrastructure damage on traditional and modern structures was assessed. Eyewitnesses were interviewed at most sites to document the chronology of the wind and

  9. Statistical Aspects of the North Atlantic Basin Tropical Cyclones: Trends, Natural Variability, and Global Warming

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2007-01-01

    Statistical aspects of the North Atlantic basin tropical cyclones for the interval 1945- 2005 are examined, including the variation of the yearly frequency of occurrence for various subgroups of storms (all tropical cyclones, hurricanes, major hurricanes, U.S. landfalling hurricanes, and category 4/5 hurricanes); the yearly variation of the mean latitude and longitude (genesis location) of all tropical cyclones and hurricanes; and the yearly variation of the mean peak wind speeds, lowest pressures, and durations for all tropical cyclones, hurricanes, and major hurricanes. Also examined is the relationship between inferred trends found in the North Atlantic basin tropical cyclonic activity and natural variability and global warming, the latter described using surface air temperatures from the Armagh Observatory Armagh, Northern Ireland. Lastly, a simple statistical technique is employed to ascertain the expected level of North Atlantic basin tropical cyclonic activity for the upcoming 2007 season.

  10. Statistical Analysis of Ensemble Forecasts of Tropical Cyclone Tracks over the North Atlantic

    DTIC Science & Technology

    2012-06-01

    OF ENSEMBLE FORECASTS OF TROPICAL CYCLONE TRACKS OVER THE NORTH ATLANTIC by Christopher E. Nixon June 2012 Thesis Advisor: Patrick A...June 2012 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Statistical Analysis of Ensemble Forecasts of Tropical Cyclone ...The skill of individual ensemble prediction systems (EPS) is evaluated in terms of the probability of a tropical cyclone (TC) track forecast being

  11. Tropical Cyclone Genesis and Sudden Changes of Track and Intensity in the Western Pacific

    DTIC Science & Technology

    2008-09-30

    Nargis revealed by multiple satellite observations. (Kazuyoshi K., B. Wang and H. Fudeyasu 2008) Tropical cyclone (TC) Nargis recently battered...tropical cyclone Nargis revealed by multiple satellite observations. Submitted to G.R.L Fudeyasu, H., Y. Wang, M. Satoh, T. Nasuno, H. Miura, and W...Tropical Cyclone Genesis and Sudden Changes of Track and Intensity in the Western Pacific PI: Bin Wang

  12. Impacts of Potential Aircraft Observations on Forecasts of Tropical Cyclones Over the Western North Pacific

    DTIC Science & Technology

    2014-12-01

    OBSERVATIONS ON FORECASTS OF TROPICAL CYCLONES OVER THE WESTERN NORTH PACIFIC by Mark C. Mitchell December 2014 Thesis Co-Advisors: Patrick A. Harr...COVERED Master’s Thesis 4. TITLE AND SUBTITLE IMPACTS OF POTENTIAL AIRCRAFT OBSERVATIONS ON FORECASTS OF TROPICAL CYCLONES OVER THE WESTERN NORTH...of the storm inner core. 14. SUBJECT TERMS Global Hawk, Tropical Cyclone Reconnaissance, Observations, Data Assimilation, Numerical Weather

  13. Sensitivity of 96 and 120-hour Numerical Model Tropical Cyclone Position Forecasts to Initial Position Errors

    DTIC Science & Technology

    2014-03-27

    storms ) were compared to Joint Typhoon Warning Center (JTWC) tropical cyclone best track data and warning bulletins in order to determine the...tropical cyclone forecasters. Bogus data does not come from actual meteorological observations, but rather the forecaster’s interpretation of storm ...experience, and more frequent and reliable storm observations. With respect to tropical cyclone observations, the Pacific basin is very different from the

  14. Comments on How Does the Boundary Layer Contribute to Eyewall Replacement Cycles in Axisymmetric Tropical Cyclones?

    DTIC Science & Technology

    2014-12-01

    CORRESPONDENCE Comments on ‘‘How Does the Boundary Layer Contribute to Eyewall Replacement Cycles in Axisymmetric Tropical Cyclones?’’ MICHAEL T...Axisymmetric Tropical Cyclones?’ 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f...hypothesis using observational data and choose instead tests using two independent cloud-representing numerical solu- tions of a mature tropical cyclone

  15. Tropical Cyclone Footprint in the Ocean Mixed Layer Observed by Argo in the Northwest Pacific

    DTIC Science & Technology

    2014-10-25

    RESEARCH ARTICLE 10.1002/2014JC010316 Tropical cyclone footprint in the ocean mixed layer observed by Argo in the Northwest Pacific HongLi Fu1...Postgraduate School, Monterey, California, USA Abstract This study systematically investigated the ocean mixed layer responses to tropical cyclone (TC...5 m, with IL cooling up to 0.4C. 1. Introduction Oceanic response to tropical cyclones (TCs) has been a hot topic due to its importance for climate

  16. Atlantic Sea Surface Temperatures and Tropical Cyclone Formation.

    NASA Astrophysics Data System (ADS)

    Shapiro, Lloyd J.; Goldenberg, Stanley B.

    1998-04-01

    It has long been accepted that interannual fluctuations in sea surface temperature (SST) in the Atlantic are associated with fluctuations in seasonal Atlantic basin tropical cyclone frequency. To isolate the physical mechanism responsible for this relationship, a singular value decomposition (SVD) is used to establish the dominant covarying modes of tropospheric wind shear and SST as well as horizontal SST gradients. The dominant SVD mode of covarying vertical shear and SST gradients, which comprises equatorially confined near-zonal vertical wind shear fluctuations across the Atlantic basin, is highly correlated with both equatorial eastern Pacific SST anomalies (associated with El Niño) and West African Sahel rainfall. While this mode is strongly related to tropical storm, hurricanes, and major hurricane frequency in the Atlantic, it is not associated with any appreciable Atlantic SST signal.By contrast, the second SVD mode of covarying vertical shear and horizontal SST gradient variability, which is effectively uncorrelated with the dominant mode, is associated with SST fluctuations concentrated in the main tropical cyclone development region between 10° and 20°N. This mode is significantly correlated with tropical storm and hurricane frequency but not with major hurricane frequency. Statistical tests confirm the robustness of the mode, and lag correlations and physical reasoning demonstrate that the SST anomalies are not due to the developing tropical cyclones themselves. Anomalies of SST and vertical shear during years where the mode has substantial amplitude confirm the resemblance of the individual fields to the modal structure, as well as the association of hurricane development with the warmer SSTs. Although SSTs are of secondary importance to vertical shear in modulating hurricane formation, explaining only 10% of the interannual variability in hurricane frequency over the 50% explained by vertical shear, the results support the conclusion that warmer

  17. Prediction of Tropical Cyclone Rapid Intensification Events

    DTIC Science & Technology

    1990-05-03

    from Weatherford and Gray, 1988). 102 6.1 Summary of outflow and ventilation differences between intensifying and non- intensifying Atlantic hurricanes ...Merrill,1988) .................... 104 6.2 Measured inner core flight level winds and radar echo velocities at 35,000 ft (10.7 km) of Hurricane Daisy...upper tropospheric temperature anomaly from the mean summer- time tropical atmosphere as measured by National Hurricane Research Lab- oratory upper

  18. Nimbus-7 total ozone observations of western North Pacific tropical cyclones

    NASA Technical Reports Server (NTRS)

    Stout, John; Rodgers, Edward B.

    1992-01-01

    The Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) was used to map the distribution of total ozone around western North Pacific tropical cyclones from 1979 to 1982. The strong correlation between total ozone distribution and tropopause height found in the subtropical and midlatitudes made it possible for TOMS to monitor the propagation of upper-tropospheric waves and the mutual adjustment between these waves and tropical cyclones during their interaction. Changes in these total ozone patterns reflect the 3D upper-tropospheric transport processes that are involved in tropical cyclone intensity and intensity and motion changes. The total ozone distributions indicate that: (1) the mean upper-tropospheric circulations associated with western North Pacific and Atlantic tropical cyclones are similar; (2) more intense tropical cyclones have higher tropopauses around their centers; (3) more intense tropical cyclones have higher tropopauses on the anticyclonic-shear side of their outflow jets, which indicate that the more intense tropical cyclones have stronger outflow channels than less intense systems; (4) tropical cyclones that intensify (do not intensify) are within 10 deg (15 deg) latitude of weak (strong) upper-tropospheric troughs that are moderately rich (very rich) in total ozone; and (5) tropical cyclones turn to the left (right) when they move within approximately 15 deg latitude downstream of an ozone-poor (ozone-rich) upper-tropospheric ridge (trough).

  19. The Variation of Tropical Cyclone Rainfall within the North Atlantic and Pacific as Observed from Satellites

    NASA Technical Reports Server (NTRS)

    Rodgers, Edward; Pierce, Harold; Adler, Robert

    1999-01-01

    Tropical cyclone monthly rainfall amounts are estimated from passive microwave satellite observations in the North Atlantic and in three equal geographical regions of the North Pacific (i.e., Western, Central, and Eastern North Pacific). These satellite-derived rainfall amounts are used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and inter-annual distribution of the 1987-1989, 1991-1998 North Atlantic and Pacific rainfall during June-November when tropical cyclones are most abundant. To estimate these tropical cyclone rainfall amounts, mean monthly rain rates are derived from the Defence Meteorological Satellite Program (DMSP) Special Sensor Microwave/ Radiometer (SSM/I) observations within 444 km radius of the center of those North Atlantic and Pacific tropical cyclones that reached storm stage and greater. These rain rate observations are then multiplied by the number of hours in a given month. Mean monthly rainfall amounts are also constructed for all the other North Atlantic and Pacific raining systems during this eleven year period for the purpose of estimating the geographical distribution and intensity of rainfall contributed by non-tropical cyclone systems. Further, the combination of the non-tropical cyclone and tropical cyclone (i.e., total) rainfall is constructed to delineate the fractional amount that tropical cyclones contributed to the total North Pacific rainfall.

  20. NASA Sees Large Tropical Cyclone Yasi Headed Toward Queensland, Australia

    NASA Image and Video Library

    2017-09-27

    NASA image acquired January 30, 2011 at 23:20 UTC. Satellite: Terra Click here to see the most recent image captured Feb. 1: www.flickr.com/photos/gsfc/5407540724/ Tropical Storm Anthony made landfall in Queensland, Australia this past weekend, and now the residents are watching a larger, more powerful cyclone headed their way. NASA's Terra satellite captured a visible image of the large Tropical Cyclone Yasi late yesterday as it makes its way west through the Coral Sea toward Queensland. The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument that flies aboard NASA's Terra satellite captured an image of Cyclone Yasi on Jan. 30 at 23:20 UTC (6:20 p.m. EST/09:20 a.m., Monday, January 31 in Australia/Brisbane local time). Although the image did not reveal a visible eye, the storm appears to be well-formed and also appears to be strengthening. Warnings and watches are already in effect throughout the Coral Sea. The Solomon Islands currently have a Tropical Cyclone warning for the provinces of Temotu, Rennell & Bellona, Makira and Guadalcanal. The Australian Bureau of Meteorology has already posted a Tropical Cyclone Watch from Cooktown to Yeppoon and inland to between Georgetown and Moranbah in Queensland, Australia. The Australian Bureau of Meteorology expects damaging winds to develop in coastal and island communities between Cooktown and Yeppoon Wednesday morning, and inland areas on Wednesday afternoon. Updates from the Australian Bureau of Meteorology can be monitored at the Bureau's website at www.bom.gov.au. On January 31 at 1500 UTC (10 a.m. EST/ 1:00 a.m. Tuesday February 1, 2011 in Australia/Brisbane local time), Tropical Cyclone Yasi had maximum sustained winds near 90 knots (103 mph/166 kmh). Yasi is a Category Two Cyclone on the Saffir-Simpson Scale. It was centered about 875 miles E of Cairns, Australia, near 13.4 South latitude and 160.4 East longitude. It was moving west near 19 knots (22 mph/35 kmh). Cyclone-force winds extend out to 30

  1. Deep convection in elliptical and polygonal eyewalls of tropical cyclones

    NASA Astrophysics Data System (ADS)

    Kuo, Hung-Chi; Cheng, Wei-Yi; Yang, Yi-Ting; Hendricks, Eric A.; Peng, Melinda S.

    2016-12-01

    In observations, tropical cyclones with cyclonically rotating elliptical eyewalls are often characterized by wave number 2 (WN2) deep convection located at the edge of the major axis. A simple modeling framework is used to understand this phenomenon, where a nondivergent barotropic model (NBM) is employed to represent the elliptical vortex in the free atmosphere, and an asymmetric slab boundary layer (SBL) model is used to simulate the frictional boundary layer (BL) underneath the free atmosphere. The interaction is one way in that the overlying cyclonic flow drives the BL, but the BL pumping does not feed back to the overlying flow. The nonlinear-balanced pressure field from the NBM drives the winds in the SBL model, which then causes BL convergence and pumping near the eyewall. The strong updrafts at the edge of the major axis for the elliptic vortex in the BL are induced by the larger convergent radial wind from the asymmetric distribution of the pressure fields of the free atmosphere with noncircular vortex. The large radial inflow maintains the supergradient wind at the edge of the elliptical vortex. The results emphasize the cyclonic rotation of the WN2 feature of strong updrafts at the top of the BL from the local shock-like BL radial wind structure. Similar radial profiles and strong BL top updrafts occur at the edges of higher-order polygonal eyewalls with the magnitude of the peak updraft decreasing as the wave number structure of the vortex increases.

  2. Satellite-observed latent heat release in a tropical cyclone

    NASA Technical Reports Server (NTRS)

    Adler, R. F.; Rodgers, E. B.

    1976-01-01

    Data from the Nimbus 5 electrically scanning microwave radiometer (ESMR) are used to make calculations of the latent heat release (L.H.R.) and the distribution of rainfall rate in a tropical cyclone as it grows from a tropical disturbance to a typhoon. The L.H.R. (calculated over a circular area of 4 deg latitude radius) increases during the development and intensification of the storm from a magnitude of 2.7 X 10 to the 21st power ergs/s (in the disturbance stage) to 8.8 X 10 to the 21st power ergs (typhoon stage). The latter value corresponds to a mean rainfall rate of 2.0 mm hr/s. The more intense the cyclone and the greater the L.H.R., the greater the percentage contribution of the larger rainfall rates to the L.H.R. In the disturbance stage the percentage contribution of rainfall rates less than or minus 6 mm hr/s is typically 8%; for the typhoon stage, the value is 38%. The distribution of rainfall rate as a function of radial distance from the center indicates that as the cyclone intensifies, the higher rainfall rates tend to concentrate toward the center of the circulation.

  3. Examining Tropical Cyclone - Kelvin Wave Interactions using Adjoint Diagnostics

    NASA Astrophysics Data System (ADS)

    Reynolds, C. A.; Doyle, J. D.; Hong, X.

    2015-12-01

    Adjoint-based tools can provide valuable insight into the mechanisms that influence the evolution and predictability of atmospheric phenomena, as they allow for the efficient and rigorous computation of forecast sensitivity to changes in the initial state. We apply adjoint-based tools from the non-hydrostatic Coupled Atmosphere/Ocean Mesoscale Prediction System (COAMPS) to explore the initial-state sensitivity and interactions between a tropical cyclone and atmospheric equatorial waves associated with the Madden Julian Oscillation (MJO) in the Indian Ocean during the DYNAMO field campaign. The development of Tropical Cyclone 5 (TC05) coincided with the passage of an equatorial Kelvin wave and westerly wind burst associated with an MJO that developed in the Indian Ocean in late November 2011, but it was unclear if and how one affected the other. COAMPS 24-h and 36-h adjoint sensitivities are analyzed for both TC05 and the equatorial waves to understand how the evolution of each system is sensitive to the other. The sensitivity of equatorial westerlies in the western Indian Ocean on 23 November shares characteristics with the classic Gill (1980) Rossby and Kelvin wave response to symmetric heating about the equator, including symmetric cyclonic circulations to the north and south of the westerlies, and enhanced heating in the area of convergence between the equatorial westerlies and easterlies. In addition, there is sensitivity in the Bay of Bengal associated with the cyclonic circulation that eventually develops into TC05. At the same time, the developing TC05 system shows strongest sensitivity to local wind and heating perturbations, but sensitivity to the equatorial westerlies is also clear. On 24 November, when the Kelvin wave is immediately south of the developing tropical cyclone, both phenomena are sensitive to each other. On 25 November TC05 no longer shows sensitivity to the Kelvin wave, while the Kelvin Wave still exhibits some weak sensitivity to TC05. In

  4. The relationship of tropical cyclone size with ENSO

    NASA Astrophysics Data System (ADS)

    Camargo, S. J.; Knaff, J. A.; Chavas, D. R.

    2015-12-01

    Recently, two independent tropical cyclone size satellite-based datasets were developed, the first by Jonh Knaff and collaborators (Knaff et al. 2014) and the second by Daniel Chavas and collaborators (Chavas et al. 2015). Estimates of TC size are available for all basins for the period 1978-2013. The climatological characteristics of TC size show interesting properties, varying by basin, TC intensity and latitude. Here we further analyze these datasets, by considering the dependence of TC size with the phases of the El Niño-Southern Oscillation (ENSO) in various basins. Preliminary results in the North Atlantic and western North Pacific, show that the TC size distributions in these basins are statistically significant distinct in El Niño and La Niña years and are basin dependent. Furthermore, these shifts in the TC size distribution are not the same for all types of storms, with different TC size distributions shifts with ENSO phase for tropical storms, hurricanes and major hurricanes. In this talk, we will present our results of on how TC distributions in all basins vary with ENSO and TC characteristics, such as intensity, lifetime, latitude, and seasonality. The differences and similarities between the results of the 2 size datasets will also be discussed. References: Chavas, D.R., N. Lin, W. Dong, and Y. Lin, 2015: Observed tropical cyclone size revisited. In prep.Knaff, J.A., S.P. Longmore, and D.A. Molenar, 2014: An objective satellite-based tropical cyclone size climatology. J. Climate, 27, 455-476.

  5. Tropical cyclone waves detected with infrasound sensor array

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-02-01

    The strong winds of a tropical cyclone whip up the sea surface, driving ocean waves a dozen meters high. When one such ocean wave runs into another wave that has an equal period but is traveling in the opposite direction, the interaction produces low-frequency sound waves that can be detected thousands of kilometers away. The infrasound signals produced by interacting ocean surface waves—known as microbarom—have typical frequencies around 0.2 hertz. Researchers previously determined that as a hurricane travels along its track, early waves generated by the storm will interact with those generated later on, producing a strong microbarom signal in the storm's wake. Researchers also found, however, that microbarom signals are produced by regular surface ocean behavior, including swell, surface waves, and nontropical cyclone storms.

  6. Air-sea interaction between tropical cyclone Nari and Kuroshio

    NASA Astrophysics Data System (ADS)

    Wu, Chau-Ron; Chang, Yu-Lin; Oey, Lie-Yauw; Chang, C.-W. June; Hsin, Yi-Chia

    2008-06-01

    The air-sea interaction between tropical cyclone Nari (Sep/6-16/2001) and Kuroshio is studied using satellite observations and an ocean model. Nari crossed the Kuroshio several times, which caused variations in typhoon intensity. Nari weakened when it was over the shelf north of Kuroshio where cooling took place due to mixing of the shallow thermocline. The cyclonic circulation penetrated much deeper for the slowly-moving storm, regardless of Nari's intensity. Near-inertial oscillations are simulated by the model in terms of the vertical displacement of isotherms. The SST cooling caused by upwelling and vertical mixing is effective in cooling the upper ocean several days after the storm had passed. At certain locations, surface chlorophyll-a concentration increases significantly after Nari's departure. Upwelling and mixing bring nutrient-rich subsurface water to the sea surface, causing enhancement of phytoplankton bloom.

  7. The Moist Entropy Change in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Juracic, Ana

    2012-10-01

    Important part of moist entropy budget is the advection of moist entropy in or out of the system, due to interaction of wind and moist entropy fields. The dropwindsonde data from several tropical storms is used to calculate both of those fields, as well as the resulting flow. In order to determine if the storm is exporting or importing moist entropy, the advection is horizontally averaged and vertically integrated. The storms of interest were Alex, Karl, Gaston and Fanapi from 2010. First three occurred in Atlantic basin while Fanapi evolved over Pacific basin. Gaston is the only one that was not developing during dropsonde missions, so it can be used as some kind of indicator of non-developing features in the entropy flux. The data show that during the development of the storm, the values of the moist entropy export are lower than for non-developing systems.

  8. Disaster triggers disaster: Earthquake triggering by tropical cyclones

    NASA Astrophysics Data System (ADS)

    Wdowinski, S.; Tsukanov, I.

    2011-12-01

    Three recent devastating earthquakes, the 1999 M=7.6 Chi-Chi (Taiwan), 2010 M=7.0 Leogane (Haiti), 2010 M=6.4 Kaohsiung (Taiwan), and additional three moderate size earthquakes (6tropical mountainous areas shortly after very wet tropical cyclones (hurricane or typhoon) hit the very same area. The most familiar example is Haiti, which was hit during the late summer of 2008 by two hurricanes and two tropical storms (Fay, Gustav, Hanna and Ike) within 25 days. A year an a half after this very wet hurricane season, the 2010 Leogane earthquake occurred in the mountainous Haiti's southern peninsula and caused the death of more than 300,000 people. The other cases are from Taiwan, which is characterized by a high seismicity level and frequent typhoon landfall. The three wettest typhoons in Taiwan's past 50 years were Morakot (in 2009, with 2885 mm or rain), Flossie (1969, 2162 mm) and Herb (1996, 1987 mm)[Lin et al., 2010]. Each of this three very wet storms was followed by one or two main-shock M>6 earthquake that occurred in the central mountainous area of Taiwan within three years after the typhoon. The 2009 Morakot typhoon was followed by 2009 M=6.2 Nantou and 2010 M=6.4 Kaohsiung earthquakes; the 1969 Flossie typhoon was followed by an M=6.3 earthquake in 1972; and the 1996 Herb typhoon by the 1998 M=6.2 Rueyli and 1999 M=7.6 Chi-Chi earthquakes. The earthquake catalog of Taiwan lists only two other M>6 main-shocks that occurred in Taiwan's central mountainous belt, one of them was in 1964 only four months after the wet Typhoon Gloria poured heavy rain in the same area. We suggest that the close proximity in time and space between wet tropical cyclones and earthquakes reflects a physical link between the two hazard types in which these earthquakes were triggered by rapid erosion induced by tropical cyclone's heavy rain. Based on remote sensing observations, meshfree finite element modeling, and Coulomb failure stress analysis, we show that the

  9. Storm-centric view of Tropical Cyclone oceanic wakes

    NASA Astrophysics Data System (ADS)

    Gentemann, C. L.; Scott, J. P.; Smith, D.

    2012-12-01

    Tropical cyclones (TCs) have a dramatic impact on the upper ocean. Storm-generated oceanic mixing, high amplitude near-inertial currents, upwelling, and heat fluxes often warm or cool the surface ocean temperatures over large regions near tropical cyclones. These SST anomalies occur to the right (Northern Hemisphere) or left (Southern Hemisphere) of the storm track, varying along and across the storm track. These wide swaths of temperature change have been previously documented by in situ field programs as well as IR and visible satellite data. The amplitude, temporal and spatial variability of these surface temperature anomalies depend primarily upon the storm size, storm intensity, translational velocity, and the underlying ocean conditions. Tropical cyclone 'cold wakes' are usually 2 - 5 °C cooler than pre-storm SSTs, and persist for days to weeks. Since storms that occur in rapid succession typically follow similar paths, the cold wake from one storm can affect development of subsequent storms. Recent studies, on both warm and cold wakes, have mostly focused on small subsets of global storms because of the amount of work it takes to co-locate different data sources to a storm's location. While a number of hurricane/typhoon websites exist that co-locate various datasets to TC locations, none provide 3-dimensional temporal and spatial structure of the ocean-atmosphere necessary to study cold/warm wake development and impact. We are developing a global 3-dimensional storm centric database for TC research. The database we propose will include in situ data, satellite data, and model analyses. Remote Sensing Systems (RSS) has a widely-used storm watch archive which provides the user an interface for visually analyzing collocated NASA Quick Scatterometer (QuikSCAT) winds with GHRSST microwave SSTs and SSM/I, TMI or AMSR-E rain rates for all global tropical cyclones 1999-2009. We will build on this concept of bringing together different data near storm locations when

  10. Structural analysis of tropical cyclone using INSAT-3D observations

    NASA Astrophysics Data System (ADS)

    Jaiswal, Neeru; Kishtawal, C. M.

    2016-05-01

    The continuous observations from visible and thermal infrared (TIR) channels of geostationary satellites are highly useful for obtaining the features associated with the shape and dynamics of cloud structures within the tropical cyclones (TCs). As TC develops from an unstructured cloud cluster and intensifies, the cloud structures become more axisymmetric around the centre of the TC. To better understand the structure of TC during different stages of its evolution i.e. from its cyclogenesis to maturity and dissipation, the continuous satellite observations plays a key role. The high spatial and temporal resolution observations from geostationary satellites are very useful in order to analyze the cloud organization during the cyclogenesis. The gradient of the brightness temperatures measures the level of symmetry of each structure, which characterizes the degree of cloud organization of the TC. In the present work, the structural analysis of TC during its life period using the observations from Indian geostationary satellite INSAT-3D has been discussed. The visible and TIR observations from INSAT-3D satellite were used to fix the center position of the cyclone which is an input for the cyclone track and intensity prediction models. This data is also used to estimate the intensity of cyclone in the advanced Dvorak technique (ADT), and in the estimation of radius of maximum winds (Rmax) of TC which is an essential input parameter for the prediction of storm surge associated to the cyclones. The different patterns of cloud structure during the intensification stage, eye-wall formation and dissipation have been discussed. The early identification of these features helps in predicting the rapid intensification of TC which in turn improves the intensity predictions.

  11. Detection of centers of tropical cyclones using Communication, Ocean, and Meteorological Satellite data

    NASA Astrophysics Data System (ADS)

    Lee, Juhyun; Im, Jungho; Park, Seohui; Yoo, Cheolhee

    2017-04-01

    Tropical cyclones are one of major natural disasters, which results in huge damages to human and society. Analyzing behaviors and characteristics of tropical cyclones is essential for mitigating the damages by tropical cyclones. In particular, it is important to keep track of the centers of tropical cyclones. Cyclone center and track information (called Best Track) provided by Joint Typhoon Warning Center (JTWC) are widely used for the reference data of tropical cyclone centers. However, JTWC uses multiple resources including numerical modeling, geostationary satellite data, and in situ measurements to determine the best track in a subjective way and makes it available to the public 6 months later after an event occurred. Thus, the best track data cannot be operationally used to identify the centers of tropical cyclones in real time. In this study, we proposed an automated approach for identifying the centers of tropical cyclones using only Communication, Ocean, and Meteorological Satellite (COMS) Meteorological Imager (MI) sensor derived data. It contains 5 bands—VIS (0.67µm), SWIR (3.7µm), WV (6.7µm), IR1 (10.8µm), and IR2 (12.0µm). We used IR1 band images to extract brightness temperatures of cloud tops over Western North Pacific between 2011 and 2012. The Angle deviation between brightness temperature-based gradient direction in a moving window and the reference angle toward the center of the window was extracted. Then, a spatial analysis index called circular variance was adopted to identify the centers of tropical cyclones based on the angle deviation. Finally, the locations of the minimum circular variance indexes were identified as the centers of tropical cyclones. While the proposed method has comparable performance for detecting cyclone centers in case of organized cloud convections when compared with the best track data, it identified the cyclone centers distant ( 2 degrees) from the best track centers for unorganized convections.

  12. The Diurnal Cycle of Precipitation in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Bowman, K. P.; Fowler, M. D.

    2015-12-01

    Position and intensity data from the International Best Track Archive for Climate Stewardship (IBTrACS) are combined with global, gridded precipitation estimates from the Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA) for the period 1998 to 2013 to study diurnal variability of precipitation in tropical cyclones. The comprehensive global coverage and large sample size afforded by the two data sets allow robust statistical analysis of storm-averaged diurnal variations and permit stratification of the data in various ways. There is a clearly detectable diurnal variation of precipitation in tropical cyclones with peak rainfall occurring near 0600 local time. For storms of all intensities the amplitude of the diurnal harmonic, which dominates the diurnal cycle, is approximately 7% of the mean rain rate. This corresponds to a peak-to-peak variation of about 15% over the course of the day. The diurnal cycle is similar in all ocean basins. There is evidence that the amplitude of the diurnal cycle increases with increasing storm intensity, but the results are not statistically significant. The results have implications for hurricane forecasting and for our understanding of the processes that regulate oceanic convection.

  13. Buoyancy in tropical cyclones and other rapidly rotating atmospheric vortices

    NASA Astrophysics Data System (ADS)

    Smith, Roger K.; Montgomery, Michael T.; Zhu, Hongyan

    2005-07-01

    Motivated primarily by its application to understanding tropical-cyclone intensification and maintenance, we re-examine the concept of buoyancy in rapidly rotating vortices, distinguishing between the buoyancy of the symmetric balanced vortex or system buoyancy, and the local buoyancy associated with cloud dynamics. The conventional definition of buoyancy is contrasted with a generalized form applicable to a vortex, which has a radial as well as a vertical component. If, for the special case of axisymmetric motions, the balanced density and pressure distribution of a rapidly rotating vortex are used as the reference state, the buoyancy field then characterizes the unbalanced density perturbations, i.e. the local buoyancy. We show how to determine such a reference state without approximation. The generation of the toroidal circulation of a vortex, which is necessary for vortex amplification, is characterized in the vorticity equation by the baroclinicity vector. This vector depends, inter-alia, on the horizontal (or radial) gradient of buoyancy evaluated along isobaric surfaces. We show that for a tropical-cyclone-scale vortex, the buoyancy so calculated is significantly different from that calculated at constant height or on surfaces of constant σ ( σ = ( p - p*)/( ps - p*), where p is the actual pressure, p* some reference pressure and ps is the surface pressure). Since many tropical-cyclone models are formulated using σ-coordinates, we examine the calculation of buoyancy on σ-surfaces and derive an expression for the baroclinicity vector in σ-coordinates. The baroclinic forcing term in the azimuthal vorticity equation for an axisymmetric vortex is shown to be approximately equal to the azimuthal component of the curl of the generalized buoyancy. A scale analysis indicates that the vertical gradient of the radial component of generalized buoyancy makes a comparatively small contribution to the generation of toroidal vorticity in a tropical cyclone, but may be

  14. Variant for estimating the activity of tropical cyclone groups in the world ocean

    NASA Astrophysics Data System (ADS)

    Yaroshevich, M. I.

    2016-12-01

    It is especially important to know the character and the intensity level of tropical cyclone (TC) activity when the system for estimating the cyclonic danger and risk is formed. During seasons of increased cyclonic activity, when several TCs are simultaneously active, the total energy effect of the cyclone group joint action is not estimated numerically. Cyclonic activity is as a rule characterized by the number of TCs that occur in the considered zone. A variant of the criterion, according to which relative cyclonic activity is estimated, is presented.

  15. The NASA CYGNSS Satellite Constellation for Tropical Cyclone Observations

    NASA Astrophysics Data System (ADS)

    Ruf, C. S.; Provost, D.; Rose, R.; Scherrer, J.; Atlas, R. M.; Chang, P.; Clarizia, M. P.; Garrison, J. L.; Gleason, S.; Katzberg, S. J.; Jelenak, Z.; Johnson, J. T.; Majumdar, S.; O'Brien, A.; Posselt, D. J.; Ridley, A. J.; Said, F.; Soisuvarn, S.; Zavorotny, V. U.

    2016-12-01

    The NASA Cyclone Global Navigation Satellite System (CYGNSS) is scheduled for launch in November 2016 to study the surface wind structure in and near the inner core of tropical cyclones. CYGNSS consists of a constellation of eight observatories carried into orbit on a single launch vehicle. Each observatory carries a 4-channel bistatic radar receiver tuned to receive GPS navigation signals scattered from the ocean surface. The eight satellites are spaced approximately twelve minutes apart in a common circular, low inclination orbit plane to provide frequent temporal sampling in the tropics. The 35deg orbit inclination results in coverage of the full globe between 38deg N and 38deg S latitude with a median(mean) revisit time of 3(7) hours The 32 CYGNSS radars operate in L-Band at a wavelength of 19 cm. This allows for adequate penetration to enable surface wind observations under all levels of precipitation, including those encountered in the inner core and eyewall of tropical cyclones. The combination of operation unaffected by heavy precipitation together with high temporal resolution throughout the life cycle of storms is expected to support significant improvements in the forecast skill of storm track and intensity, as well as better situational awareness of the extent and structure of storms in near real time. A summary of the properties of the CYGNSS science data products will be presented, together with an update on the results of ongoing Observation System Simulation Experiments performed by members of the CYGNSS science team over the past four years, in particular addressing the expected impact on storm track and intensity forecast skill. With launch scheduled for the month prior to AGU, the on orbit status of the constellation will also be presented.

  16. Parameter Uncertainty on AGCM-simulated Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    He, F.

    2015-12-01

    This work studies the parameter uncertainty on tropical cyclone (TC) simulations in Atmospheric General Circulation Models (AGCMs) using the Reed-Jablonowski TC test case, which is illustrated in Community Atmosphere Model (CAM). It examines the impact from 24 parameters across the physical parameterization schemes that represent the convection, turbulence, precipitation and cloud processes in AGCMs. The one-at-a-time (OAT) sensitivity analysis method first quantifies their relative importance on TC simulations and identifies the key parameters to the six different TC characteristics: intensity, precipitation, longwave cloud radiative forcing (LWCF), shortwave cloud radiative forcing (SWCF), cloud liquid water path (LWP) and ice water path (IWP). Then, 8 physical parameters are chosen and perturbed using the Latin-Hypercube Sampling (LHS) method. The comparison between OAT ensemble run and LHS ensemble run shows that the simulated TC intensity is mainly affected by the parcel fractional mass entrainment rate in Zhang-McFarlane (ZM) deep convection scheme. The nonlinear interactive effect among different physical parameters is negligible on simulated TC intensity. In contrast, this nonlinear interactive effect plays a significant role in other simulated tropical cyclone characteristics (precipitation, LWCF, SWCF, LWP and IWP) and greatly enlarge their simulated uncertainties. The statistical emulator Extended Multivariate Adaptive Regression Splines (EMARS) is applied to characterize the response functions for nonlinear effect. Last, we find that the intensity uncertainty caused by physical parameters is in a degree comparable to uncertainty caused by model structure (e.g. grid) and initial conditions (e.g. sea surface temperature, atmospheric moisture). These findings suggest the importance of using the perturbed physics ensemble (PPE) method to revisit tropical cyclone prediction under climate change scenario.

  17. Global view of the upper level outflow patterns associated with tropical cyclone intensity changes during FGGE

    NASA Technical Reports Server (NTRS)

    Chen, L.; Gray, W. M.

    1985-01-01

    The characteristics of the upper tropospheric outflow patterns which occur with tropical cyclone intensification and weakening over all of the global tropical cyclone basins during the year long period of the First GARP Global Experiment (FGGE) are discussed. By intensification is meant the change in the tropical cyclone's maximum wind or central pressure, not the change of the cyclone's outer 1 to 3 deg radius mean wind which we classify as cyclone strength. All the 80 tropical cyclones which existed during the FGGE year are studied. Two-hundred mb wind fields are derived from the analysis of the European Center for Medium Range Weather Forecasting (ECMWF) which makes extensive use of upper tropospheric satellite and aircraft winds. Corresponding satellite cloud pictures from the polar orbiting U.S. Defense Meteorological Satellite Program (DMSP) and other supplementary polar and geostationary satellite data are also used.

  18. Analysis of North Atlantic Tropical Cyclone Intensify Change Using Data Mining

    ERIC Educational Resources Information Center

    Tang, Jiang

    2010-01-01

    Tropical cyclones (TC), especially when their intensity reaches hurricane scale, can become a costly natural hazard. Accurate prediction of tropical cyclone intensity is very difficult because of inadequate observations on TC structures, poor understanding of physical processes, coarse model resolution and inaccurate initial conditions, etc. This…

  19. Analysis of North Atlantic Tropical Cyclone Intensify Change Using Data Mining

    ERIC Educational Resources Information Center

    Tang, Jiang

    2010-01-01

    Tropical cyclones (TC), especially when their intensity reaches hurricane scale, can become a costly natural hazard. Accurate prediction of tropical cyclone intensity is very difficult because of inadequate observations on TC structures, poor understanding of physical processes, coarse model resolution and inaccurate initial conditions, etc. This…

  20. Factors That Influence the Size of Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Wang, Shuai; Toumi, Ralf; Czaja, Arnaud; Van Kan, Adrian

    2015-04-01

    Tropical cyclone (TC) size is an important feature setting the extent of coastal flooding, the size of storm surge and area threatened by landfall. The importance of TC size is demonstrated comparing Hurricanes Sandy in 2012 and Bret in 1999. As a Saffir-Simpson Hurricane Scale category-3 hurricane, the radius of gale-force wind of Hurricane Sandy exceeded 800 km prior to landfall, and the storm caused catastrophic storm surge into the New Jersey and New York coastlines, and damage up to an estimated total of 50 billion. Hurricane Bret, on the other hand, was a more intense category-4 hurricane with a radius of gale-force wind of only 140 km. Although Bret's intensity is considerable, damage was reported to be relatively light, totalling an estimated 60 million. The difference impacts are mainly caused by the difference in size. Despite the fact that a wide range of observed TC sizes has been recognised, the underlying factors that control both individual storm size and the climatological size variation remain mysterious. Here an idealized full-physics numerical cyclone model and a modified hurricane steady-state model (λ model) for TC wind profile are used to investigate the influence of environmental temperature and initial vortex properties on TC size. In the simulation we find that a sea surface temperature increase, a temperature decrease in the upper troposphere, a large or strong initial vortex can lead to the extension of TC size. The numerical model simulations show a Gaussian distribution with width, λ, of the moist entropy in the boundary layer. The width, λ, has good linear relationship with the size changes caused by different factors. With regards to TC size and intensity, we find that, unlike the intensity prediction based on the maximum potential intensity theory, it seems that there is no upper limit for TC size providing there is sufficient latent heat flux. The increase of TC size at the steady stage also causes a slight drop in intensity. In

  1. Statistical Analysis of Ensemble Forecasts of Tropical Cyclone Tracks over the Northwest Pacific Ocean

    DTIC Science & Technology

    2012-09-01

    ABBREVIATIONS AGBOM Australia Government Bureau of Meteorology AOR Area of Responsibility ATCF Automated Tropical Cyclone Forecast ATE Along-Track Error...cited 2012: Australian Government Bureau of Meteorology (AGBOM) Tropical Cyclone Page [Available online at http://www.bom.gov.au/cyclone/cxmlinfo...reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instruction

  2. Simulated ocean response to tropical cyclones: The effect of a novel parameterization of mixing from unbroken surface waves

    NASA Astrophysics Data System (ADS)

    Stoney, Lachlan; Walsh, Kevin; Babanin, Alexander V.; Ghantous, Malek; Govekar, Pallavi; Young, Ian

    2017-06-01

    Tropical cyclones dissipate large amounts of energy into the upper ocean, locally enhancing vertical mixing and cooling the sea surface. In this study, we investigate how the response of the ocean to tropical cyclones is affected by additional mixing from unbroken surface waves. This "Surface Wave Mixing" (SWM) is represented by a novel parameterization, in which the wave orbital motion contributes directly to the production of turbulent kinetic energy. The parameterization is implemented here as a modification to the k-ɛ turbulence scheme, used within an ocean model with 1/4° horizontal resolution (MOM5). This model is forced with idealized tropical cyclone wind fields based on observed case studies. Relative to simulations without SMW, the inclusion of SWM leads to surface temperature differences of around 0.5°C near the storm track, typically with warm anomalies on the side with the strongest winds and cool anomalies in other regions. This pattern is explained by an initial wave-induced deepening of the mixed layer, which can modify the subsequent shear-induced entrainment and upwelling. The temperature anomalies from SWM could potentially influence tropical cyclone intensity and structure.

  3. Projection of future changes in the frequency of intense tropical cyclones

    NASA Astrophysics Data System (ADS)

    Sugi, Masato; Murakami, Hiroyuki; Yoshida, Kohei

    2017-07-01

    Recent modeling studies have consistently shown that the global frequency of tropical cyclones will decrease but that of very intense tropical cyclones may increase in the future warmer climate. It has been noted, however, that the uncertainty in the projected changes in the frequency of very intense tropical cyclones, particularly the changes in the regional frequency, is very large. Here we present a projection of the changes in the frequency of intense tropical cyclones estimated by a statistical downscaling of ensemble of many high-resolution global model experiments. The results indicate that the changes in the frequency of very intense (category 4 and 5) tropical cyclones are not uniform on the globe. The frequency will increase in most regions but decrease in the south western part of Northwest Pacific, the South Pacific, and eastern part of the South Indian Ocean.

  4. Tropical Cyclone Initiation by the Tropical Upper Tropospheric Trough

    DTIC Science & Technology

    1976-02-01

    Fernandez- Partagas and Estoque (1970) showed that the majority of tropical disturbances in the eastern Caribbean Sea and BOMEX area were induced by...10-25, 1967. University of Miami Tech. Report under Grant No. E-22-29-69-G, 42 pp. Fernandez-Partagas, J.J., and M. Estoque , 1970: A preliminary

  5. Relationship of maximum tropical cyclone intensity to sea surface temperature and tropical cyclone heat potential in the North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Wada, Akiyoshi; Usui, Norihisa; Sato, Kanako

    2012-06-01

    We investigated whether the maximum intensity of tropical cyclones (TC) in the North Pacific Ocean depends on sea surface temperature (SST) and tropical cyclone heat potential (TCHP). The study used reanalysis data sets for both the oceans and atmosphere: daily, 10-day, and monthly oceanic data sets; six-hour and monthly atmospheric data sets; and a daily satellite SST data set, for the July-to-October season from 2002 to 2005. For each TC, we summed TCHP from the time of genesis to the time of first reaching a minimum central pressure (MCP), to obtain an accumulated TCHP. In a linear regression analysis, the relationship between maximum TC intensity and accumulated TCHP differed between the eastern and western Pacific: high values of accumulated TCHP were needed before a TC attained a certain MCP in the western Pacific. In addition, the background convective available potential energy (CAPE) value was nearly four times larger in the western Pacific than in the eastern Pacific. The static stability was also 6.5% lower, the inertial stability 29.7% higher, and the size of tropical cyclones 38.2% larger in the western Pacific than in the eastern Pacific. The result indicated a deeper Rossby penetration depth and stronger TC in the western Pacific. Finally, we validated the TCHP values derived from three oceanic reanalysis data sets by using Argo profiling float observations. We found that use of only the daily data can reproduce the cooling effect of a passage of a TC, which caused a decrease in the TCHP values.

  6. Recurving western North Pacific tropical cyclones and midlatitude predictability

    NASA Astrophysics Data System (ADS)

    Aiyyer, A.

    2015-09-01

    Data from an ensemble prediction system are used to examine the impact of recurving tropical cyclones on downstream midlatitude forecasts. The ensemble spread, normalized by its climatology, increases after recurvature and peaks approximately 4-5 days later. It returns to climatological levels within a week after recurvature. Initially, the spread increases around the position of the tropical storm. Subsequently, it increases after extratropical transition, and it is associated with a developing wave packet in the midlatitude storm track. The enhanced spread propagates downstream approximately at the group speed of the wave packet. These results suggest that relative to the model's baseline, recurvature-related increase in loss of forecast skill is spatially and temporally localized. Further, energy dispersion of the developing wave packet may constrain the rate at which the forecast errors propagate downstream.

  7. The impact of tropical cyclone size on North Atlantic ACE and PDI

    NASA Astrophysics Data System (ADS)

    Fritz, A. M.; Belanger, J. I.; Curry, J. A.

    2008-12-01

    Climatologies of hurricane activity such as Accumulated Cyclone Energy (ACE) and Power Dissipation Index (PDI) are produced by integrating over the life cycle of the storm using maximum surface wind speeds. However, these calculations ignore the size of the tropical cyclone, which varies substantially and is independent of maximum intensity. Integrating over the size of the tropical cyclone could provide a better estimate of potential damage from a TC and can also provide a more accurate index of how tropical cyclones are responding to changes in global climate. We use two data sets of tropical cyclone size: the Extended Best Track (1988-2007) and U.S. landfall size (1920-2007). The radius of outer closed isobar is used to determine TC size in both data sets. The pressure-wind relationship model of Holland (1980) is used to provide 2-dimensional winds for each tropical cyclone. Analysis is done to compare the traditional ACE and PDI estimates (using only the maximum surface wind) with the new estimates that are integrated over the size of the tropical cyclone. Incorporation of size into the indices produces a more accurate assessment of the strength of a tropical cyclone in terms of kinetic energy and landfall impact, and is more suited for use in climate trend studies.

  8. Classic Maya civilization collapse associated with reduction in tropical cyclone activity

    NASA Astrophysics Data System (ADS)

    Medina, M. A.; Polanco-Martinez, J. M.; Lases-Hernández, F.; Bradley, R. S.; Burns, S. J.

    2013-12-01

    In light of the increased destructiveness of tropical cyclones observed over recent decades one might assume that an increase and not a decrease in tropical cyclone activity would lead to societal stress and perhaps collapse of ancient cultures. In this study we present evidence that a reduction in the frequency and intensity of tropical Atlantic cyclones could have contributed to the collapse of the Maya civilization during the Terminal Classic Period (TCP, AD. 800-950). Statistical comparisons of a quantitative precipitation record from the Yucatan Peninsula (YP) Maya lowlands, based on the stalagmite known as Chaac (after the Mayan God of rain and agriculture), relative to environmental proxy records of El Niño/Southern Oscillation (ENSO), tropical Atlantic sea surface temperatures (SSTs), and tropical Atlantic cyclone counts, suggest that these records share significant coherent variability during the TCP and that summer rainfall reductions between 30 and 50% in the Maya lowlands occurred in association with decreased Atlantic tropical cyclones. Analysis of modern instrumental hydrological data suggests cyclone rainfall contributions to the YP equivalent to the range of rainfall deficits associated with decreased tropical cyclone activity during the collapse of the Maya civilization. Cyclone driven precipitation variability during the TCP, implies that climate change may have triggered Maya civilization collapse via freshwater scarcity for domestic use without significant detriment to agriculture. Pyramid in Tikal, the most prominent Maya Kingdom that collapsed during the Terminal Classic Period (circa C.E. 800-950) Rainfall feeding stalagmites inside Rio Secreto cave system, Yucatan, Mexico.

  9. Measuring wind and stress under tropical cyclones with scatterometer

    NASA Astrophysics Data System (ADS)

    Liu, W. Timothy

    2016-07-01

    Ocean surface stress, the turbulent transport of momentum, is largely derived from wind through a drag coefficient. In tropical cyclones (TC), scatterometers have difficulty in measuring strong wind and there is large uncertainty in the drag coefficient. We postulate that the microwave backscatter from ocean surface roughness, which is in equilibrium with local stress, does not distinguish weather systems. The reduced sensitivity of scatterometer wind retrieval algorithm under the strong wind is an air-sea interaction problem that is caused by a change in the behavior of the drag coefficient and not a sensor problem. Under this assumption, we applied a stress retrieval algorithm developed over a moderate wind range to retrieve stress under the strong winds of TCs. Over a moderate wind range, the abundant wind measurements and more established drag coefficient value allow sufficient stress data to be computed from wind to develop a stress retrieval algorithm for the scatterometer. Using unprecedented large amount of stress retrieved from the scatterometer coincident with strong winds in TC, we showed that the drag coefficient decreases with wind speed at a much steeper rate than previously revealed, for wind speeds over 25 m/s. The result implies that the ocean applies less drag to inhibit TC intensification and the TC causes less ocean mixing and surface cooling than previous studies indicated. With continuous and extensive coverage from constellations of scatterometers for several decades, the impact of tropical cyclones on the ocean and the feedback from the ocean are examined.

  10. Coastal morphological change and inundation predictions due to tropical cyclones

    NASA Astrophysics Data System (ADS)

    Penko, A.; Veeramony, J.

    2016-02-01

    Predictions of the peak, onset, and duration of inundation generated by tropical cyclones are necessary for the mustering of humanitarian assistance and disaster response teams. Typically, storm surge and inundation modeling neglects the often significant morphologic change that occurs during extreme storm events. Previous work has shown that using numerical models that couple only wave and circulation (neglecting morphologic change) underestimate the duration of inundation resulting from tropical cyclones. We hypothesize that inundation predictions would be improved by accounting for the effects of morphologic change below and above mean water level in the model hydrodynamics. This hypothesis is tested using the coupled Delft3D FLOW-WAVE-MOR model to make hydrodynamic and morphologic predictions at Galveston Bay, TX during Hurricane Ike. Additionally, we explore the effects of the terraqueous bottom roughness and rainfall on the predictions of the extent and duration of inundation. Model predictions of significant wave heights and water levels are compared to USGS and NDBC observations. Predictions of morphologic change are compared to measured post-storm bathymetry.

  11. Evaluation of WAVEWATCH III Wave Model under Tropical Cyclone Conditions

    NASA Astrophysics Data System (ADS)

    Port, J.; Hara, T.; Reichl, B. G.; Ginis, I.

    2016-02-01

    In order to best prepare coastal regions for incoming storms, the ability to model tropical cyclone (hurricane) track and intensity has never been more vital. The ocean surface wave field (sea state) may significantly impact the storm intensity forecast because it modifies the air-sea momentum and heat fluxes as well as the upper ocean turbulent mixing. Therefore, it is important to include accurate sea state predictions in hurricane prediction models. The WAVEWATCH III (WW3) is one of the most skillful surface wave models and NOAA plans to incorporate it in the next generation hurricane prediction models. However, WW3 performance under hurricane conditions has not been thoroughly tested and requires further validations against observational data. This study compares the significant wave height (SWH) predicted by WW3 with satellite and Scanning Radar Altimeter (SRA) observational results during Hurricanes Irene (2011) and Edouard (2014). The WW3 data is generated with and without considering ocean currents and with different wind forcing products. The inclusion of currents generally reduces the predicted SWH and improves the correlation between WW3 predictions and observational data. While both SRA and satellite data offer reasonably good correlations with the WW3 data, the standard deviation of the satellite data from the WW3 data is significantly smaller than that of the SRA data. The generally good correlation found between the observational SWH readings and the SWH values from WW3 supports the validity of the WW3 wave model results under tropical cyclone conditions.

  12. Increasing destructiveness of tropical cyclones over the past 30 years.

    PubMed

    Emanuel, Kerry

    2005-08-04

    Theory and modelling predict that hurricane intensity should increase with increasing global mean temperatures, but work on the detection of trends in hurricane activity has focused mostly on their frequency and shows no trend. Here I define an index of the potential destructiveness of hurricanes based on the total dissipation of power, integrated over the lifetime of the cyclone, and show that this index has increased markedly since the mid-1970s. This trend is due to both longer storm lifetimes and greater storm intensities. I find that the record of net hurricane power dissipation is highly correlated with tropical sea surface temperature, reflecting well-documented climate signals, including multi-decadal oscillations in the North Atlantic and North Pacific, and global warming. My results suggest that future warming may lead to an upward trend in tropical cyclone destructive potential, and--taking into account an increasing coastal population--a substantial increase in hurricane-related losses in the twenty-first century.

  13. Tropical Cyclone Forecasters Reference Guide 2. Tropical Climatology

    DTIC Science & Technology

    1992-04-01

    tropical circulation and weather patterns, and vice versa. Time-lapsed movies of cloud imageries from geostationary satellites often show cloud bands...intense low tropospheric convergence and moisture, convective cloudiness, and rainfall prevail in and to the east of the trough. Cloud clusters...seen on satellite cloud imageries, are usually associated with the waves. A majority of these waves are cold-core, and the axis of the wave tilts toward

  14. Trade-off between intensity and frequency of global tropical cyclones

    NASA Astrophysics Data System (ADS)

    Kang, Nam-Young; Elsner, James B.

    2015-07-01

    Global tropical cyclone climate has been investigated with indicators of frequency, intensity and activity. However, a full understanding of global warming's influence on tropical cyclone climate remains elusive because of the incomplete nature of these indicators. Here we form a complete three-dimensional variability space of tropical cyclone climate where the variabilities are continuously linked and find that global ocean warmth best explains the out-of-phase relationship between intensity and frequency of global tropical cyclones. In a year with greater ocean warmth, the tropical troposphere is capped by higher pressure anomaly in the middle and upper troposphere even with higher moist static energy anomaly in the lower troposphere, which is thought to inhibit overall tropical cyclone occurrences but lead to greater intensities. A statistical consequence is the trade-off between intensity and frequency. We calculate an average increase in global tropical cyclone intensity of 1.3 m s-1 over the past 30 years of ocean warming occurring at the expense of 6.1 tropical cyclones worldwide.

  15. Trade-off between Intensity and Frequency of Global Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Kang, N. Y.; Elsner, J.

    2015-12-01

    Global tropical cyclone climate has been investigated with indicators of frequency, intensity and activity. However, a full understanding of global warming's influence on tropical cyclone climate remains elusive because of the incomplete nature of these indicators. Here we form a complete three-dimensional variability space of tropical cyclone climate where the variabilities are continuously linked and find that global ocean warmth best explains the out-of-phase relationship between intensity and frequency of global tropical cyclones. In a year with greater ocean warmth, the tropical troposphere is capped by higher pressure anomaly in the middle and upper troposphere even with higher moist static energy anomaly in the lower troposphere, which is thought to inhibit overall tropical cyclone occurrences but lead to greater intensities. Statistical consequence is the trade-off between intensity and frequency. We calculate an average increase in global tropical cyclone intensity of 1.3 m/s over the past 30 years of ocean warming occurring at the expense of 6.1 tropical cyclones worldwide.

  16. Microphysical Characteristics of Developing Tropical Cyclones During NAMMA 2006

    NASA Astrophysics Data System (ADS)

    Pratt, A. S.; Jenkins, G.; Heymsfield, A.

    2007-05-01

    Aerosols interacting with clouds can have profound impacts on the microphysical structure of these clouds and can affect precipitation formation processes. A modeling study in the 1990's (Rogers et al 1994) noted that a 100- fold increase in ice nuclei (IN) concentration resulted in cloud water depletion and the prevention of homogeneous freezing in maritime cumulus cloud. Several studies conducted during CRYSTAL-FACE (DeMott et al 2003; Sassen et al 2003) noted IN concentrations 20-100 above normal values and glaciation of altocumulus clouds at unusually warm temperatures, both due to Saharan dust. Finally, Koren et al (2005) denoted changes in convective cloud properties due to the effects of aerosols. These effects, particularly on convective clouds, might be important for larger-scale processes, such as tropical cyclogenesis. The microphysical characteristics (liquid water content, particle concentration, etc.) of two developing tropical cyclones (Tropical Depression 8 and Tropical Storm Debby from the 2006 Atlantic Hurricane Season) will be presented. In particular, the possible effects of dust on the microphysics, as well as implications for cyclogenesis will be explored. These data were taken on board the NASA DC-8 during the NAMMA 2006 field campaign. Preliminary results suggest a relationship between increased aerosol concentrations and higher amounts of cloud ice water content and cloud-sized particle concentrations.

  17. Tropical Cyclones in Simulations of the Middle Holocene

    NASA Astrophysics Data System (ADS)

    Korty, R. L.; Zamora, R. A.; Camargo, S. J.; Toomey, M.

    2015-12-01

    The environmental conditions that support and sustain tropical cyclones are affected by the amount of solar radiation incident on the tropics, which varies on millennial timescales owing to orbital variations. During the middle Holocene, higher amounts of summer solar radiation 6000 years ago (6ka) increased thermal stability and pools of hot, dry air in the tropical troposphere, rendering the thermodynamic environment less favorable than in modern times. (The opposite response is seen in the Southern Hemisphere, where January-March anomalies yield more conducive conditions 6ka there than today.) Here we compare these changes in environmental conditions to tropical storms simulated by two distinct methods as well as to available geologic evidence from the middle Holocene. We find that storms directly spawned by global climate models respond to the changes as the thermodynamic environment predicts: a reduction 6ka in Northern Hemisphere, with an increase 6ka in the Southern Hemisphere. We derive an empirical genesis index that identifies the best fit between environmental conditions and the response in genesis. We also compare the results to storms generated using the statistical downscaling method pioneered by Emanuel. Here too the events similarly respond to the changes in the environmental conditions, but the amplitude of the changes is smaller than seen in the global climate models. We discuss some possible reasons for the differences as well as their implications for studies applying these methods to 21st century climate.

  18. Cyclone Driven Sediment Loads in a Tropical Mega-River.

    NASA Astrophysics Data System (ADS)

    Darby, Stephen; Leyland, Julian; Hackney, Christopher; Heasley, Eleanore; Kummu, Matti; Lauri, Hannu; Parsons, Daniel; Nicholas, Andrew; Aalto, Rolf; Best, Jim

    2015-04-01

    floodplain reaches of Cambodia. Furthermore, it is shown that the proportion of flux generated from tropical cyclones increases downstream and dominates (~60%) the flux observed around the confluence of the 3S basin (the Se San, Sre Pok and Se Kong Rivers) which drains the Vietnamese highlands. This implies future changes in cyclone tracks may impact upon sediment delivery to the Mekong delta.

  19. Mediterranean Tropical-like Cyclones: Present and Future

    NASA Astrophysics Data System (ADS)

    Cavicchia, Leone; von Storch, Hans; Gualdi, Silvio

    2014-05-01

    The Mediterranean basin is characterized by the genesis of a large number of cyclonic systems. Most of the cyclones generated in this area have a baroclinic nature. A few storms every year, however, develop a dynamical evolution similar to the one of tropical cyclones, showing an axis-symmetric vertical profile, a warm core, a cloud-free eye surrounded by a cloud cover with spiral shape, and winds up to the hurricane speed. The strongest between such storms exhibit a striking resemblance to the lower-latitudes hurricanes, except for the mesoscale spatial extent, and have thus been termed medicanes (Mediterranean hurricanes). Medicanes are considered rare phenomena, - the number of observed cases documented in the literature is around ten - but are associated to severe damage on coastal areas. Due to the scarcity of observations over sea, and to the coarse resolution of the long-term reanalysis datasets, it is difficult to construct a homogeneous statistics of the formation of medicanes. Using an approach (tested on a number of historical medicane cases) based on the high-resolution dynamical downscaling of the NCEP/NCAR reanalysis, and exploiting an objective detection algorithm specifically designed to single out the features of medicanes, the statistical properties of such storms (annual cycle, decadal and inter-annual variability, geographical distribution, trends) over the last six decades have been studied in a systematic way, and the linkage between the frequency of medicanes formation and synoptic patterns has been investigated. It was found that medicanes occur indeed with a low frequency, and that they are formed mostly during the cold season in the western Mediterranean and in the region extending between the Ionian Sea and the northern coast of Africa. The analysis of the environmental factors related with the formation of medicanes shows that the genesis mechanism requires a sufficiently large difference between the sea surface temperature and the

  20. Tropical Cyclones in Simulations of the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Zamora, R. A.; Korty, R. L.; Camargo, S. J.

    2015-12-01

    How tropical cyclones respond to large-scale changes in climate is an important and complex question. Here we study the question using the response to the climate forcing of the Last Glacial Maximum (LGM). Utilizing two detecting and tracking algorithms of tropical cyclones (TC), we assess the sensitivity of the genesis and frequency of TCs in a 1° x 1° simulation of a global climate model (CCSM), a limited-area simulation (western north Pacific; WNP) of the higher resolution WRF model (36 km horizontal resolution), and the statistical downscaling approach developed by Emanuel. We assess how changes between the LGM and 20th century climatology of TCs are related to changes in the large-scale environmental variables known to be important to TCs (e.g. vorticity, wind shear, and available moisture). Several facets of the TC climatology at the LGM are similar across all three modeling techniques: regions that spawn TCs and their seasonal cycle at the LGM is similar to the present-day distribution, while the total counts are slightly reduced at the LGM. The average intensity in the WRF model (which features resolution high enough to resolve strong storms) is similar between the two climates, though the distribution of intensity is more concentrated at the LGM (there are fewer weak events and fewer of the strongest events at the LGM). Conditions are similarly favorable in much of the deep tropics at the LGM compared to the 20th century, particularly in the central and western Pacific, but conditions become more hostile at the subtropical margins. We compare the resulting climatology with the underlying changes in environmental factors, and empirically derive a genesis index to identify the best fit between changes in the factors and climatology of events.

  1. Assessment of Tropical Cyclone Track Forecast Errors using GDAPS (UM)

    NASA Astrophysics Data System (ADS)

    Kim, D.; Kim, J.; Chang, K.; Byun, K.; Lee, J.

    2013-12-01

    After the Joint Typhoon Warning Center (JTWC) began issuing official five-day tropical cyclone (TC) forecasts in 2003, the Korea Meteorological Administration (KMA) started issuing official five-day forecasts of TCs in May 2012 after 2 year of beta test. Forming a selective consensus (SCON) by proper removal of a likely erroneous track forecast is hypothesized to be more accurate than the non-selective consensus (NCON) of all model tracks that are used for the five-day forecasts. Conceptual models describing large track error mechanisms, which are related to known tropical cyclone motion processes being misrepresented in the dynamical models, are applied to forecasts during the 2012 western North Pacific typhoon season by the Global Data Assimilation and Prediction System (GDAPS (UM N512 L70)) which is KMA's main operational model. GDAPS (UM) is one of consensus members used in making KMA's five-day forecasts and thus analysis of its track error tendencies would be useful for forming a SCON forecast. All 72-h track errors greater than 320 km are examined on the basis of the approach developed by Carr and Elsberry (2000a, b). Tropical-influenced error sources caused 37% (47 times / 126 erroneous forecasts) of the GDAPS (UM) large track forecast errors primarily because an incorrect beta effect-related process depicted by the model contributed to the erroneous forecasts. Midlatitude-influenced error sources accounted for 63% (79 times / 126 error cases) in the GDAPS (UM) erroneous forecasts mainly due to an incorrect forecast of the midlatitude system evolutions. It is proposed that KMA will be able to issue more reliable TC track information if a likely model track error is recognized by optimum use of conceptual models by Carr and Elsberry (2000a, b) and a selective consensus track is then the basis for an improved warning.

  2. Impacts of Tropical Cyclones and Accompanying Precipitation on Infectious Diarrhea in Cyclone Landing Areas of Zhejiang Province, China

    PubMed Central

    Deng, Zhengyi; Xun, Huanmiao; Zhou, Maigeng; Jiang, Baofa; Wang, Songwang; Guo, Qing; Wang, Wei; Kang, Ruihua; Wang, Xin; Marley, Gifty; Ma, Wei

    2015-01-01

    Background: Zhejiang Province, located in southeastern China, is frequently hit by tropical cyclones. This study quantified the associations between infectious diarrhea and the seven tropical cyclones that landed in Zhejiang from 2005–2011 to assess the impacts of the accompanying precipitation on the studied diseases. Method: A unidirectional case-crossover study design was used to evaluate the impacts of tropical storms and typhoons on infectious diarrhea. Principal component analysis (PCA) was applied to eliminate multicollinearity. A multivariate logistic regression model was used to estimate the odds ratios (ORs) and the 95% confidence intervals (CIs). Results: For all typhoons studied, the greatest impacts on bacillary dysentery and other infectious diarrhea were identified on lag 6 days (OR = 2.30, 95% CI: 1.81–2.93) and lag 5 days (OR = 3.56, 95% CI: 2.98–4.25), respectively. For all tropical storms, impacts on these diseases were highest on lag 2 days (OR = 2.47, 95% CI: 1.41–4.33) and lag 6 days (OR = 2.46, 95% CI: 1.69–3.56), respectively. The tropical cyclone precipitation was a risk factor for both bacillary dysentery and other infectious diarrhea when daily precipitation reached 25 mm and 50 mm with the largest OR = 3.25 (95% CI: 1.45–7.27) and OR = 3.05 (95% CI: 2.20–4.23), respectively. Conclusions: Both typhoons and tropical storms could contribute to an increase in risk of bacillary dysentery and other infectious diarrhea in Zhejiang. Tropical cyclone precipitation may also be a risk factor for these diseases when it reaches or is above 25 mm and 50 mm, respectively. Public health preventive and intervention measures should consider the adverse health impacts from tropical cyclones. PMID:25622139

  3. Impacts of tropical cyclones and accompanying precipitation on infectious diarrhea in cyclone landing areas of Zhejiang Province, China.

    PubMed

    Deng, Zhengyi; Xun, Huanmiao; Zhou, Maigeng; Jiang, Baofa; Wang, Songwang; Guo, Qing; Wang, Wei; Kang, Ruihua; Wang, Xin; Marley, Gifty; Ma, Wei

    2015-01-22

    Zhejiang Province, located in southeastern China, is frequently hit by tropical cyclones. This study quantified the associations between infectious diarrhea and the seven tropical cyclones that landed in Zhejiang from 2005-2011 to assess the impacts of the accompanying precipitation on the studied diseases. A unidirectional case-crossover study design was used to evaluate the impacts of tropical storms and typhoons on infectious diarrhea. Principal component analysis (PCA) was applied to eliminate multicollinearity. A multivariate logistic regression model was used to estimate the odds ratios (ORs) and the 95% confidence intervals (CIs). For all typhoons studied, the greatest impacts on bacillary dysentery and other infectious diarrhea were identified on lag 6 days (OR = 2.30, 95% CI: 1.81-2.93) and lag 5 days (OR = 3.56, 95% CI: 2.98-4.25), respectively. For all tropical storms, impacts on these diseases were highest on lag 2 days (OR = 2.47, 95% CI: 1.41-4.33) and lag 6 days (OR = 2.46, 95% CI: 1.69-3.56), respectively. The tropical cyclone precipitation was a risk factor for both bacillary dysentery and other infectious diarrhea when daily precipitation reached 25 mm and 50 mm with the largest OR = 3.25 (95% CI: 1.45-7.27) and OR = 3.05 (95% CI: 2.20-4.23), respectively. Both typhoons and tropical storms could contribute to an increase in risk of bacillary dysentery and other infectious diarrhea in Zhejiang. Tropical cyclone precipitation may also be a risk factor for these diseases when it reaches or is above 25 mm and 50 mm, respectively. Public health preventive and intervention measures should consider the adverse health impacts from tropical cyclones.

  4. Contributions of tropical waves to tropical cyclone genesis over the western North Pacific

    NASA Astrophysics Data System (ADS)

    Wu, Liang; Takahashi, Masaaki

    2017-09-01

    The present study investigates the relationship between the tropical waves and the tropical cyclone (TC) genesis over the western North Pacific (WNP) for the period 1979-2011. Five wave types are considered in this study. It is shown that the TC genesis is strongly related to enhanced low-level vorticity and convection of tropical waves and significant difference are detected in the TC modulation by dynamic and thermodynamic components of the waves. More TCs tend to form in regions of waves with overlapping cyclonic vorticity and active convection. About 83.2% of TCs form within active phase of tropical waves, mainly in a single wave and two coexisting waves. Each wave type-related genesis accounts for about 30% of all TC geneses except for the Kelvin waves that account for only 25.2% of TC geneses. The number of each wave type-related TC genesis consistently varies seasonally with peak in the TC season (July-November), which is attributed to a combined effect of active wave probability and intensity change. The interannual variation in the TC genesis is well reproduced by the tropical wave-related TC genesis, especially in the region east of 150°E. An eastward extension of the enhanced monsoon trough coincides with increased tropical wave activity by accelerated wave-mean flow interaction.

  5. Testing coral-based tropical cyclone reconstructions: An example from Puerto Rico

    USGS Publications Warehouse

    Kilbourne, K. Halimeda; Moyer, Ryan P.; Quinn, Terrence M.; Grottoli, Andrea G.

    2011-01-01

    Complimenting modern records of tropical cyclone activity with longer historical and paleoclimatological records would increase our understanding of natural tropical cyclone variability on decadal to centennial time scales. Tropical cyclones produce large amounts of precipitation with significantly lower δ18O values than normal precipitation, and hence may be geochemically identifiable as negative δ18O anomalies in marine carbonate δ18O records. This study investigates the usefulness of coral skeletal δ18O as a means of reconstructing past tropical cyclone events. Isotopic modeling of rainfall mixing with seawater shows that detecting an isotopic signal from a tropical cyclone in a coral requires a salinity of ~ 33 psu at the time of coral growth, but this threshold is dependent on the isotopic composition of both fresh and saline end-members. A comparison between coral δ18O and historical records of tropical cyclone activity, river discharge, and precipitation from multiple sites in Puerto Rico shows that tropical cyclones are not distinguishable in the coral record from normal rainfall using this approach at these sites.

  6. An Estimate of the North Atlantic Basin Tropical Cyclone Activity for the 2011 Hurricane Season

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2011-01-01

    Estimates are presented for the expected level of tropical cyclone activity for the 2011 North Atlantic Basin hurricane season. It is anticipated that the frequency of tropical cyclones for the North Atlantic Basin during the 2011 hurricane season will be near to above the post-1995 means. Based on the Poisson distribution of tropical cyclone frequencies for the current more active interval 1995-2010, one computes P(r) = 63.7% for the expected frequency of the number of tropical cyclones during the 2011 hurricane season to be 14 plus or minus 3; P(r) = 62.4% for the expected frequency of the number of hurricanes to be 8 plus or minus 2; P(r) = 79.3% for the expected frequency of the number of major hurricanes to be 3 plus or minus 2; and P(r) = 72.5% for the expected frequency of the number of strikes by a hurricane along the coastline of the United States to be 1 plus or minus 1. Because El Nino is not expected to recur during the 2011 hurricane season, clearly, the possibility exists that these seasonal frequencies could easily be exceeded. Also examined are the effects of the El Nino-Southern Oscillation phase and climatic change (global warming) on tropical cyclone seasonal frequencies, the variation of the seasonal centroid (latitude and longitude) location of tropical cyclone onsets, and the variation of the seasonal peak wind speed and lowest pressure for tropical cyclones.

  7. The impact of the diurnal insolation cycle on the tropical cyclone heat engine

    NASA Astrophysics Data System (ADS)

    O'Neill, Morgan E.; Perez-Betancourt, Diamilet; Wing, Allison A.

    A hurricane, or tropical cyclone, is understood as a heat engine that moves heat from the warm sea surface to the cold tropopause. The efficiency of this engine depends in part on the strength and duration of solar heating. Over land, peak rainfall associated with individual thunderstorms occurs in the late afternoon. Over ocean, with its markedly higher surface heat capacity, deep convection responds more to radiational cooling than daytime surface heating. However, the role of daily varying solar forcing on the dynamics of tropical cyclones is poorly understood. Recently, Dunion et al. (2014) reported significant, repeating diurnal behavior propagating outward from tropical cyclone centers, using infrared imagery from nine years of North Atlantic tropical cyclones. We study the impact of the diurnal cycle on tropical cyclones using a high resolution 3D numerical model, the System for Atmospheric Modeling (Khairoutdinov and Randall 2003). Simulations are run with and without variable sunlight. We are able to reproduce the observational finding of Dunion et al. (2014), and further identify a diurnally-varying residual circulation in the tropical cyclone at midlevels. The impact of the diurnal cycle on the equilibrium dynamics of tropical cyclones is also discussed.

  8. Do tropical cyclones shape shorebird habitat patterns? Biogeoclimatology of snowy plovers in Florida.

    PubMed

    Convertino, Matteo; Elsner, James B; Muñoz-Carpena, Rafael; Kiker, Gregory A; Martinez, Christopher J; Fischer, Richard A; Linkov, Igor

    2011-01-12

    The Gulf coastal ecosystems in Florida are foci of the highest species richness of imperiled shoreline dependent birds in the USA. However environmental processes that affect their macroecological patterns, like occupancy and abundance, are not well unraveled. In Florida the Snowy Plover (Charadrius alexandrinus nivosus) is resident along northern and western white sandy estuarine/ocean beaches and is considered a state-threatened species. Here we show that favorable nesting areas along the Florida Gulf coastline are located in regions impacted relatively more frequently by tropical cyclones. The odds of Snowy Plover nesting in these areas during the spring following a tropical cyclone impact are seven times higher compared to the odds during the spring following a season without a cyclone. The only intensity of a tropical cyclone does not appear to be a significant factor affecting breeding populations. Nevertheless a future climate scenario featuring fewer, but more extreme cyclones could result in a decrease in the breeding Snowy Plover population and its breeding range. This is because the spatio-temporal frequency of cyclone events was found to significantly affect nest abundance. Due to the similar geographic range and habitat suitability, and no decrease in nest abundance of other shorebirds in Florida after the cyclone season, our results suggest a common bioclimatic feedback between shorebird abundance and tropical cyclones in breeding areas which are affected by cyclones.

  9. Do Tropical Cyclones Shape Shorebird Habitat Patterns? Biogeoclimatology of Snowy Plovers in Florida

    PubMed Central

    Convertino, Matteo; Elsner, James B.; Muñoz-Carpena, Rafael; Kiker, Gregory A.; Martinez, Christopher J.; Fischer, Richard A.; Linkov, Igor

    2011-01-01

    Background The Gulf coastal ecosystems in Florida are foci of the highest species richness of imperiled shoreline dependent birds in the USA. However environmental processes that affect their macroecological patterns, like occupancy and abundance, are not well unraveled. In Florida the Snowy Plover (Charadrius alexandrinus nivosus) is resident along northern and western white sandy estuarine/ocean beaches and is considered a state-threatened species. Methodology/Principal Findings Here we show that favorable nesting areas along the Florida Gulf coastline are located in regions impacted relatively more frequently by tropical cyclones. The odds of Snowy Plover nesting in these areas during the spring following a tropical cyclone impact are seven times higher compared to the odds during the spring following a season without a cyclone. The only intensity of a tropical cyclone does not appear to be a significant factor affecting breeding populations. Conclusions/Significance Nevertheless a future climate scenario featuring fewer, but more extreme cyclones could result in a decrease in the breeding Snowy Plover population and its breeding range. This is because the spatio-temporal frequency of cyclone events was found to significantly affect nest abundance. Due to the similar geographic range and habitat suitability, and no decrease in nest abundance of other shorebirds in Florida after the cyclone season, our results suggest a common bioclimatic feedback between shorebird abundance and tropical cyclones in breeding areas which are affected by cyclones. PMID:21264268

  10. Remote forcing of water levels by tropical cyclones in southwest Australia

    NASA Astrophysics Data System (ADS)

    Eliot, Matthew; Pattiaratchi, Charitha

    2010-08-01

    Tropical cyclones (termed hurricanes and typhoons in other regions), are extreme events associated with strong winds, torrential rain and storm surges (in coastal areas) and cause extensive damage as a result of strong winds and flooding (caused by either heavy rainfall or ocean storm surges) in the immediate area of impact. The eastern Indian Ocean, particularly in the northwest region of Australia, is impacted by up to 10 tropical cyclones during the cyclone season, although direct impact of cyclones along the west and southwest coastlines is rare. However, the sub-tidal frequency component of sea level records along the west and south coasts of Western Australia indicates lagged correspondence with the occurrence of tropical cyclones. It is demonstrated that the tropical cyclones generate a continental shelf wave which travels along the west and south coasts of Australia up to 3500 km with speeds of 450-500 km day -1 (5.2-5.8 ms -1) with maximum trough to crest wave height of 0.63 m, comparable with the mean daily tidal range in the region. The shelf wave is identified in the coastal sea level records, initially as a decrease in water level, 1-2 days after the passage of the cyclone and has a period of influence up to 10 days. Amplitude of the shelf wave was strongly affected by the path of the tropical cyclone, with cyclones travelling parallel to the west coast typically producing the most significant signal due to resonance and superposition with local forcing. Analysis of water levels from Port Hedland, Geraldton, Fremantle and Albany together with cyclone paths over a ten year period (1988-1998) indicated that the tropical cyclones paths may be classified into 6 different types based on the amplitude of the wave.

  11. Global Losses and Declining Vulnerability to Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Narita, D.; Hsiang, S. M.

    2011-12-01

    Approach An extreme environmental event may generate different losses for different societies. If the physical exposure to an event is held fixed, then the magnitude of a society's loss defines its vulnerability to that event. Competing hypotheses suggest that social and economic developments could make vulnerability rise or fall over time, but previous studies have been unable to reject either hypothesis because they lacked accurate data on societies' physical exposure to extreme events. We address this problem for a specific type of event by reconstructing the exposure of 233 countries to every tropical cyclone (TC) on the planet between 1950 and 2008 in making use of the Limited Information Cyclone Reconstruction and Integration for Climate and Economics (LICRICE) model [Hsiang, 2010]. By filling a critical data gap, this reconstruction enables us to compare how revenue losses, damages, and deaths from physically similar events change over time. Our approach contrasts with a large literature, which relies almost exclusively on self-reporting data of TC damages compiled by the Emergency Events Database (EM-DAT)[OFDA/CRED, 2009]. Results On a global scale, we find that populations rapidly mitigate certain TC risks, reducing their reported damages from a TC of low intensity by a remarkable 9.4% yr-1 and death rates by 5.1% yr-1 (Figure 1). However, these rapid reductions in vulnerability are not evident for the highest intensity TCs and lost agricultural revenues, which are more difficult to observe than deaths or damages, exhibit non-declining vulnerability for events of all intensities. Because the vulnerability of agriculture has remained high while vulnerability to damages has declined rapidly, our results indicate that lost agricultural revenues have dominated TC losses ever since ˜1990. References Hsiang, S. M. (2010). Temperatures and cyclones strongly associated with economic production in the Caribbean and Central America. Proceedings of the National

  12. Decadal Trends of Atlantic Basin Tropical Cyclones (1950-1999)

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    Ten-year moving averages of the seasonal rates for "named storms," tropical storms, hurricanes, and major (or intense) hurricanes in the Atlantic basin reveal that the present epoch is one of enhanced activity (i.e., having seasonal rates typically equal to or above respective long-term median rates). For example, the 10-year moving average of the seasonal rates for named storms is now higher than for any previous year over the past 50 years, measuring 10.65 in 1994, or 2.65 units higher than its median rate of 8. For tropical storms, its 10-year moving average has more than doubled over the past 50 years, from 2.15 in 1955 to 4.60 in 1992, with 16 of the past 20 years having a seasonal rate of 3 or more (the median rate). For hurricanes and major hurricanes, their 10-year moving averages turned upward, rising above long-term median rates (5.5 and 2, respectively) in 1992, following a 25-year lull in activity. Taken together, the outlook for this year and immediately succeeding years is for all categories of Atlantic basin tropical cyclones to have seasonal rates at levels equal to or above their long-term median rates, especially during non-El Nino-related seasons. Only during El Nino-related seasons does it appear that seasonal rates might be slightly diminished.

  13. Decadal Trends of Atlantic Basin Tropical Cyclones (1950-1999)

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2001-01-01

    Ten-year moving averages of the seasonal rates for 'named storms,' tropical storms, hurricanes, and major (or intense) hurricanes in the Atlantic basin suggest that the present epoch is one of enhanced activity, marked by seasonal rates typically equal to or above respective long-term median rates. As an example, the 10-year moving average of the seasonal rates for named storms is now higher than for any previous year over the past 50 years, measuring 10.65 in 1994, or 2.65 units higher than its median rate of 8. Also, the 10-year moving average for tropical storms has more than doubled, from 2.15 in 1955 to 4.60 in 1992, with 16 of the past 20 years having a seasonal rate of three or more (the median rate). For hurricanes and major hurricanes, their respective 10-year moving averages turned upward, rising above long-term median rates (5.5 and 2, respectively) in 1992, a response to the abrupt increase in seasonal rates that occurred in 1995. Taken together, the outlook for future hurricane seasons is for all categories of Atlantic basin tropical cyclones to have seasonal rates at levels equal to or above long-term median rates, especially during non-El Nino-related seasons. Only during El Nino-related seasons does it appear likely that seasonal rates might be slightly diminished.

  14. Statistical Aspects of Tropical Cyclone Activity in the North Atlantic Basin, 1945-2010

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2012-01-01

    Examined are statistical aspects of the 715 tropical cyclones that formed in the North Atlantic basin during the interval 1945-2010. These 715 tropical cyclones include 306 storms that attained only tropical storm strength, 409 hurricanes, 179 major or intense hurricanes, and 108 storms that struck the US coastline as hurricanes. Comparisons made using 10-year moving average (10-yma) values between tropical cyclone parametric values and surface air and ENSO-related parametric values indicate strong correlations to exist, in particular, against the Armagh Observatory (Northern Ireland) surface air temperature, the Atlantic Multi-decadal Oscillation (AMO) index, the Atlantic Meridional Mode (AMM) index, and the North Atlantic Oscillation (NAO) index, in addition to the Oceanic Ni o index (ONI) and Quasi-Biennial Oscillation (QBO) indices. Also examined are the decadal variations of the tropical cyclone parametric values and a look ahead towards the 2012 hurricane season and beyond.

  15. Changes in Tropical Cyclone Intensity Over the Past 30 Years: A Global and Dynamic Perspective

    NASA Technical Reports Server (NTRS)

    Wu, Liguang; Wang, Bin; Braun, Scott A.

    2006-01-01

    The hurricane season of 2005 was the busiest on record and Hurricane Katrina (2005) is believed to be the costliest hurricane in U. S. history. There are growing concerns regarding whether this increased tropical cyclone activity is a result of global warming, as suggested by Emanuel(2005) and Webster et al. (2005), or just a natural oscillation (Goldenberg et al. 2001). This study examines the changes in tropical cyclone intensity to see what were really responsible for the changes in tropical cyclone activity over the past 30 years. Since the tropical sea surface temperature (SST) warming also leads to the response of atmospheric circulation, which is not solely determined by the local SST warming, this study suggests that it is better to take the tropical cyclone activities in the North Atlantic (NA), western North Pacific (WNP) and eastern North Pacific (ENP) basins as a whole when searching for the influence of the global-scale SST warming on tropical cyclone intensity. Over the past 30 years, as the tropical SST increased by about 0.5 C, the linear trends indicate 6%, 16% and 15% increases in the overall average intensity and lifetime and the annual frequency. Our analysis shows that the increased annual destructiveness of tropical cyclones reported by Emanuel(2005) resulted mainly from the increases in the average lifetime and annual frequency in the NA basin and from the increases in the average intensity and lifetime in the WNP basin, while the annual destructiveness in the ENP basin generally decreased over the past 30 years. The changes in the proportion of intense tropical cyclones reported by Webster et a1 (2005) were due mainly to the fact that increasing tropical cyclones took the tracks that favor for the development of intense tropical cyclones in the NA and WNP basins over the past 30 years. The dynamic influence associated with the tropical SST warming can lead to the impact of global warming on tropical cyclone intensity that may be very

  16. Simulated sensitivity of the tropical cyclone eyewall replacement cycle to the ambient temperature profile

    NASA Astrophysics Data System (ADS)

    Ma, Xulin; He, Jie; Ge, Xuyang

    2017-09-01

    In this study, the impacts of the environmental temperature profile on the tropical cyclone eyewall replacement cycle are examined using idealized numerical simulations. It is found that the environmental thermal condition can greatly affect the formation and structure of a secondary eyewall and the intensity change during the eyewall replacement cycle. Simulation with a warmer thermal profile produces a larger moat and a prolonged eyewall replacement cycle. It is revealed that the enhanced static stability greatly suppresses convection, and thus causes slow secondary eyewall formation. The possible processes influencing the decay of inner eyewall convection are investigated. It is revealed that the demise of the inner eyewall is related to a choking effect associated with outer eyewall convection, the radial distribution of moist entropy fluxes within the moat region, the enhanced static stability in the inner-core region, and the interaction between the inner and outer eyewalls due to the barotropic instability. This study motivates further research into how environmental conditions influence tropical cyclone dynamics and thermodynamics.

  17. Sensitivity of Tropical Cyclone Spinup Time to the Initial Entropy Deficit

    NASA Astrophysics Data System (ADS)

    Tang, B.; Corbosiero, K. L.; Rios-Berrios, R.; Alland, J.; Berman, J.

    2014-12-01

    The development timescale of a tropical cyclone from genesis to the start of rapid intensification in an axisymmetric model is hypothesized to be a function of the initial entropy deficit. We run a set of idealized simulations in which the initial entropy deficit between the boundary layer and free troposphere varies from 0 to 100 J kg-1 K-1. The development timescale is measured by changes in the integrated kinetic energy of the low-level vortex. This timescale is inversely related to the mean mass flux during the tropical cyclone gestation period. The mean mass flux, in turn, is a function of the statistics of convective updrafts and downdrafts. Contour frequency by altitude diagrams show that entrainment of dry air into updrafts is predominately responsible for differences in the mass flux between the experiments, while downdrafts play a secondary role. Analyses of the potential and kinetic energy budgets indicate less efficient conversion of available potential energy to kinetic energy in the experiments with higher entropy deficits. Entrainment leads to the loss of buoyancy and the destruction of available potential energy. In the presence of strong downdrafts, there can even be a reversal of the conversion term. Weaker and more radially confined radial inflow results in less convergence of angular momentum in the experiments with higher entropy deficits. The result is a slower vortex spinup and a reduction in steady-state vortex size, despite similar steady-state maximum intensities among the experiments.

  18. Daily Tropical Cyclone Intensity Response to Solar Ultraviolet Variations

    NASA Astrophysics Data System (ADS)

    Elsner, J.; Jagger, T.; Hodges, R.

    2009-12-01

    An inverse relationship between hurricane frequency and intensity over the Caribbean and the number of sunspots has been recently identified. Here we investigate this relationship and find support for the hypothesis that changes in ultraviolet (UV) radiation rather than changes in other concomitant solar and cosmic variations are the cause. The relationship is statistically significant after accounting for variation in ocean heat and the El Niño cycle. A cooling response in the upper troposphere due to decreased solar UV forcing on photochemistry, radiative heating, and dynamics in the stratosphere increases the atmosphere's convective available potential energy leading to a stronger cyclone. The mean amplitude of the intensity response is 4.3 ± 1.86 m/s per 0.01 Mg II units (s.d.), which is quantitatively consistent with the heat-engine theory of tropical cyclone intensity but is less sensitive by a factor of 2 to 3 to an equivalent amount of warming at the ocean surface.

  19. Avoided Impacts in Ensembles of Tropical Cyclone Damage Potential

    NASA Astrophysics Data System (ADS)

    Done, J.; Paimazumder, D.; Holland, G. J.; Towler, E.

    2014-12-01

    Anthropogenic climate change has the potential to alter current levels of Tropical Cyclone (TC) damage, yet the degree of change and its importance relative to changes in exposure and vulnerability are debated. This study isolates the climate drivers of TC damage and develops an approach to translate climate model data directly to a measure of Cyclone Damage Potential (CDP). The actual damage then depends on a given user's impacted exposure and vulnerability. Our approach is motivated by recent work that highlighted the importance of accounting for TC size and TC translation speed in addition to maximum wind speed in driving TC damage. Since coarse resolution climate models are not able to adequately capture many TC characteristics, these key damaging parameters are modeled in terms of large-scale climate variables, to sidestep the need for information on individual TCs and to enable assessments of CDP directly from large-scale climate model data. The CDP is applied to ensembles of future climates generated under a range of anthropogenic forcing scenarios to assess the degree of avoided CDP under lower emission pathways. Users may then translate avoided CDP to avoided losses using relationships between CDP and their specific exposure and vulnerability characteristics.

  20. North Atlantic Basin Tropical Cyclone Activity in Relation to Temperature and Decadal- Length Oscillation Patterns

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2009-01-01

    Yearly frequencies of North Atlantic basin tropical cyclones, their locations of origin, peak wind speeds, average peak wind speeds, lowest pressures, and average lowest pressures for the interval 1950-2008 are examined. The effects of El Nino and La Nina on the tropical cyclone parametric values are investigated. Yearly and 10-year moving average (10-yma) values of tropical cyclone parameters are compared against those of temperature and decadal-length oscillation, employing both linear and bi-variate analysis, and first differences in the 10-yma are determined. Discussion of the 2009 North Atlantic basin hurricane season, updating earlier results, is given.

  1. Rapid intensification and the bimodal distribution of tropical cyclone intensity

    PubMed Central

    Lee, Chia-Ying; Tippett, Michael K.; Sobel, Adam H.; Camargo, Suzana J.

    2016-01-01

    The severity of a tropical cyclone (TC) is often summarized by its lifetime maximum intensity (LMI), and the climatological LMI distribution is a fundamental feature of the climate system. The distinctive bimodality of the LMI distribution means that major storms (LMI >96 kt) are not very rare compared with less intense storms. Rapid intensification (RI) is the dramatic strengthening of a TC in a short time, and is notoriously difficult to forecast or simulate. Here we show that the bimodality of the LMI distribution reflects two types of storms: those that undergo RI during their lifetime (RI storms) and those that do not (non-RI storms). The vast majority (79%) of major storms are RI storms. Few non-RI storms (6%) become major storms. While the importance of RI has been recognized in weather forecasting, our results demonstrate that RI also plays a crucial role in the TC climatology. PMID:26838056

  2. Jason Tracks Powerful Tropical Cyclone Gonu's High Winds, Waves

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Wind Speed Wave Height Click on images for larger versions

    This pair of images from the radar altimeter instrument on the U.S./France Jason mission reveals information on wind speeds and wave heights of Tropical Cyclone Gonu, which reached Category 5 strength in the Arabian Sea prior to landfall in early June 2007. Strong winds near 20 meters per second and wave heights of greater than 5 meters were recorded. These high waves are extremely rare in the Arabian Sea and exacerbated heavy flooding from the storm surge over much of the Oman coastline.

    The U.S. portion of the Jason mission is managed by JPL for NASA's Science Mission Directorate, Washington, D.C. Research on Earth's oceans using Jason and other space-based capabilities is conducted by NASA's Science Mission Directorate to better understand and protect our home planet.

  3. Revisiting trough interactions and tropical cyclone intensity change

    NASA Astrophysics Data System (ADS)

    Peirano, C. M.; Corbosiero, K. L.; Tang, B. H.

    2016-05-01

    An updated climatology of Atlantic basin tropical cyclone (TC) intensity change in the presence of upper tropospheric trough forcing is presented. To control for changes in the background thermodynamic environment, a methodology that normalizes intensity change by the potential intensity of the TC is used to more narrowly focus on the effect of troughs compared to previous studies. Relative to the full sample of Atlantic TCs, troughs are a negative influence on intensification: trough interaction cases are 4% less likely to intensify and 5% more likely to weaken. Troughs are especially detrimental compared to TCs without trough forcing: trough interaction cases are 14% less likely to intensify and 13% more likely to weaken. Additionally, eddy flux convergence of angular momentum, previously shown to positively affect TC intensity change, is shown to be a weak predictor of intensity change compared to vertical wind shear, which is enhanced during a trough interaction.

  4. Suspended sediment transport during tropical-cyclone floods in Fiji

    NASA Astrophysics Data System (ADS)

    Kostaschuk, Ray; Terry, James; Raj, Rishi

    2003-04-01

    Flow records, rising-stage sediment samplers, and a sand suspension model are used to examine suspended sediment concentrations during major floods caused by tropical cyclones TC Joni and TC Kina in the Rewa River, Fiji. The highest concentrations of total suspended solids were measured during the early stages of TC Kina. The suspension model predicts higher sand concentrations for TC Kina compared with TC Joni because of the larger slope and higher shear stresses during Kina. Extremely high wash load concentrations early in TC Kina are at least partly due to remobilization of fine sediment deposited during the earlier TC Joni flood. Samples from the TC Kina had volumetric concentrations larger than 5%, indicating hyperconcentrated streamflows. Mass-density shear stresses in the hyperconcentrated flows are up 1·6 times larger than clear-water shear stresses, but they occur early during low stages of the flood and probably do not result in severe bed erosion.

  5. An Ocean-Based Potential Intensity Index for Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Lin, I. I.; Black, P. G.; Price, J. F.; Yang, C.; Chen, S. S.; Chi, N.; Harr, P.; Lien, C.; D'Asaro, E. A.; Wu, C.

    2012-12-01

    Improvement in tropical cyclones' intensity prediction is an important ongoing effort. Cooling of the ocean by storm mixing reduces storm intensity by reducing the air-sea enthalpy flux. Here, we modify the widely used Sea Surface Temperature Potential Intensity (SST_PI) index by including information from the upper subsurface ocean to form a new Ocean Cooling Potential Intensity index, OC_PI. Applied to a 14-year (1998-2011) Western Pacific typhoon archive, the correlation coefficient between the predicted maximum intensity and the observed peak intensity increased from 0.08 to 0.31. For the sub group of slow-moving TCs that has the strongest interaction with subsurface ocean, r2 increases to 0.56. OC_PI thus contributes to the improvement on the existing PI through incorporation of ocean's subsurface information.

  6. Differential leaflet mortality may influence biogeochemical cycling following tropical cyclones.

    PubMed

    Marler, Thomas E; Ferreras, Ulysses

    2014-01-01

    Intensity of tropical cyclones is expected to increase in the coming century, and an improved understanding of their influence on biogeochemical cycles would benefit ecologists and conservationists. We studied the November 2013 Typhoon Haiyan damage to observe that numerous examples of partial leaf necrosis on intact leaves of trees in the Cycadaceae and Arecaceae families resulted, leaving behind a copious amount of arboreal dead leaf material attached to live leaves. The decay process of this form of arboreal litter has not been previously studied. When compared with decay of ground litter or detached litter suspended in the canopy, we predict the decay process of this form of arboreal litter will include increased photooxidation, leaching, and comminution by detritivorous insects and mites; but decreased catabolism of organic molecules by saprophytic organisms.

  7. Tropical cyclones in ERA-40: A detection and tracking method

    NASA Astrophysics Data System (ADS)

    Kleppek, S.; Muccione, V.; Raible, C. C.; Bresch, D. N.; Koellner-Heck, P.; Stocker, T. F.

    2008-05-01

    A tracking method for tropical cyclones (TCs) is presented and their characteristics for data sets with a lower horizontal resolution, e.g., the ERA-40 Reanalysis data set from 1958 to 2001 are explored. The tracking method uses sea level pressure, relative vorticity and wind speed at 850 hPa, and vertical wind shear. The method, assessed in the Atlantic basin, identifies a realistic number of TCs. However, the ERA-40 TCs compared with best track data from the U.S. National Hurricane Center are too weak to reach hurricane character, i.e., the tracked TCs do not show hurricanes of category three to five. Another caveat is that the life cycle of central pressure values is often not realistically reproduced by ERA-40 TCs. To correct the life cycle of the central pressure, a two-step statistical downscaling approach is applied to the ERA-40 TCs which strongly improves the finding of major hurricanes.

  8. Observational evidence for an ocean heat pump induced by tropical cyclones.

    PubMed

    Sriver, Ryan L; Huber, Matthew

    2007-05-31

    Ocean mixing affects global climate and the marine biosphere because it is linked to the ocean's ability to store and transport heat and nutrients. Observations have constrained the magnitude of upper ocean mixing associated with certain processes, but mixing rates measured directly are significantly lower than those inferred from budget analyses, suggesting that other processes may play an important role. The winds associated with tropical cyclones are known to lead to localized mixing of the upper ocean, but the hypothesis that tropical cyclones are important mixing agents at the global scale has not been tested. Here we calculate the effect of tropical cyclones on surface ocean temperatures by comparing surface temperatures before and after storm passage, and use these results to calculate the vertical mixing induced by tropical cyclone activity. Our results indicate that tropical cyclones are responsible for significant cooling and vertical mixing of the surface ocean in tropical regions. Assuming that all the heat that is mixed downwards is balanced by heat transport towards the poles, we calculate that approximately 15 per cent of peak ocean heat transport may be associated with the vertical mixing induced by tropical cyclones. Furthermore, our analyses show that the magnitude of this mixing is strongly related to sea surface temperature, indicating that future changes in tropical sea surface temperatures may have significant effects on ocean circulation and ocean heat transport that are not currently accounted for in climate models.

  9. Developing an enhanced tropical cyclone data portal for the Southern Hemisphere and the Western Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Kuleshov, Yuriy; de Wit, Roald; Atalifo, Terry; Prakash, Bipendra; Waqaicelua, Alipate; Kunitsugu, Masashi; Caroff, Philippe; Chane-Ming, Fabrice

    2013-04-01

    Tropical cyclones are the most extreme weather phenomena which severely impact coastal communities and island nations. There is an ongoing research (i) on accurate analysis of observed trends in tropical cyclone occurrences, and (ii) how tropical cyclone frequency and intensity may change in the future as a result of climate change. Reliable historical records of cyclone activity are vital for this research. The Pacific Australia Climate Change Science and Adaptation Planning (PACCSAP) program is dedicated to help Pacific Island countries and Timor Leste gain a better understanding of how climate change will impact their regions. One of the key PACCSAP projects is focused on developing a tropical cyclone archive, climatology and seasonal prediction for the regions. As part of the project, historical tropical cyclone best track data have been examined and prepared to be subsequently displayed through the enhanced tropical cyclone data portal for the Southern Hemisphere and the Western Pacific Ocean. Data from the Regional Specialised Meteorological Centre (RSMC) Nadi, Fiji and Tropical Cyclone Warning Centres (TCWCs) in Brisbane, Darwin and Wellington for 1969-1970 to 2010-2011 tropical cyclone seasons have been carefully examined. Errors and inconsistencies which have been found during the quality control procedure have been corrected. To produce a consolidated data set for the South Pacific Ocean, best track data from these four centres have been used. Specifically, for 1969-1970 to 1994-1995 tropical cyclone seasons, data from TCWCs in Brisbane, Darwin and Wellington have been used. In 1995, RSMC Nadi, Fiji has been established with responsibilities for issuing tropical cyclone warnings and preparing best track data for the area south of the equator to 25°S, 160°E to 120°W. Consequently, data from RSMC Nadi have been used as a primary source for this area, starting from the 1995-1996 tropical cyclone season. These data have been combined with the data from

  10. Tropical cyclone cooling combats region-wide coral bleaching.

    PubMed

    Carrigan, Adam D; Puotinen, Marji

    2014-05-01

    Coral bleaching has become more frequent and widespread as a result of rising sea surface temperature (SST). During a regional scale SST anomaly, reef exposure to thermal stress is patchy in part due to physical factors that reduce SST to provide thermal refuge. Tropical cyclones (TCs - hurricanes, typhoons) can induce temperature drops at spatial scales comparable to that of the SST anomaly itself. Such cyclone cooling can mitigate bleaching across broad areas when well-timed and appropriately located, yet the spatial and temporal prevalence of this phenomenon has not been quantified. Here, satellite SST and historical TC data are used to reconstruct cool wakes (n=46) across the Caribbean during two active TC seasons (2005 and 2010) where high thermal stress was widespread. Upon comparison of these datasets with thermal stress data from Coral Reef Watch and published accounts of bleaching, it is evident that TC cooling reduced thermal stress at a region-wide scale. The results show that during a mass bleaching event, TC cooling reduced thermal stress below critical levels to potentially mitigate bleaching at some reefs, and interrupted natural warming cycles to slow the build-up of thermal stress at others. Furthermore, reconstructed TC wave damage zones suggest that it was rare for more reef area to be damaged by waves than was cooled (only 12% of TCs). Extending the time series back to 1985 (n = 314), we estimate that for the recent period of enhanced TC activity (1995-2010), the annual probability that cooling and thermal stress co-occur is as high as 31% at some reefs. Quantifying such probabilities across the other tropical regions where both coral reefs and TCs exist is vital for improving our understanding of how reef exposure to rising SSTs may vary, and contributes to a basis for targeting reef conservation. © 2014 John Wiley & Sons Ltd.

  11. Landfall tropical cyclone rainstorms on the north slope of the Dabie Mountains

    NASA Astrophysics Data System (ADS)

    Huang, Z. Y.; Wang, J. Y.; Lee, C.

    2016-08-01

    The formation and development mechanism of landfall cyclone rainstorms that occur on the north slope of the Dabie Mountains were investigated by the determination of typical occurrences. Interaction between the tropical cyclone and the westerly trough was characterized by the favorable circulation backgrounds of landfall tropical cyclone rainstorms on the north slope of the Dabie Mountains. A conveyor belt was created between the easterly jet flow of the tropical cyclone and the subtropical high pressure of the western equatorial Pacific Ocean and the southerly jet flow of the westerly trough front, creating a huge amount of energy and vapor from the landfall tropical cyclone in the rainstorm area and destabilizing the stratification. These conditions were advantageous to the frontogenesis of a warm front and the development of Mesoscale convective systems (MCS) in the westerly cold air that met the inverted trough located at the northern portion of the tropical cyclone. The existence and development of the mesoscale front area in the ground provide a trigger mechanism for the rainstorm. The MCS occurred and developed in the equivalent potential temperature theta se (θse) frontal zone, which is located between the low pressure area of the typhoon and the cold air, which is located at the rear of the westerly trough. The terrain block slowed or stopped the motion of the low pressure system formed by the landfall tropical cyclone, which was conducive to the enhancement of the rainstorm.

  12. Arabian Sea tropical cyclones intensified by emissions of black carbon and other aerosols.

    PubMed

    Evan, Amato T; Kossin, James P; Chung, Chul Eddy; Ramanathan, V

    2011-11-02

    Throughout the year, average sea surface temperatures in the Arabian Sea are warm enough to support the development of tropical cyclones, but the atmospheric monsoon circulation and associated strong vertical wind shear limits cyclone development and intensification, only permitting a pre-monsoon and post-monsoon period for cyclogenesis. Thus a recent increase in the intensity of tropical cyclones over the northern Indian Ocean is thought to be related to the weakening of the climatological vertical wind shear. At the same time, anthropogenic emissions of aerosols have increased sixfold since the 1930s, leading to a weakening of the southwesterly lower-level and easterly upper-level winds that define the monsoonal circulation over the Arabian Sea. In principle, this aerosol-driven circulation modification could affect tropical cyclone intensity over the Arabian Sea, but so far no such linkage has been shown. Here we report an increase in the intensity of pre-monsoon Arabian Sea tropical cyclones during the period 1979-2010, and show that this change in storm strength is a consequence of a simultaneous upward trend in anthropogenic black carbon and sulphate emissions. We use a combination of observational, reanalysis and model data to demonstrate that the anomalous circulation, which is radiatively forced by these anthropogenic aerosols, reduces the basin-wide vertical wind shear, creating an environment more favourable for tropical cyclone intensification. Because most Arabian Sea tropical cyclones make landfall, our results suggest an additional impact on human health from regional air pollution.

  13. The Impact of Dry Saharan Air on Tropical Cyclone Intensification

    NASA Technical Reports Server (NTRS)

    Braun, Scott A.

    2012-01-01

    The controversial role of the dry Saharan Air Layer (SAL) on tropical storm intensification in the Atlantic will be addressed. The SAL has been argued in previous studies to have potential positive influences on storm development, but most recent studies have argued for a strong suppressing influence on storm intensification as a result of dry air, high stability, increased vertical wind shear, and microphysical impacts of dust. Here, we focus on observations of Hurricane Helene (2006), which occurred during the NASA African Monsoon Multidisciplinary Activities (NAMMA) experiment. Satellite and airborne observations, combined with global meteorological analyses depict the initial environment of Helene as being dominated by the SAL, although with minimal evidence that the SAL air actually penetrated to the core of the disturbance. Over the next several days, the SAL air quickly moved westward and was gradually replaced by a very dry, dust-free layer associated with subsidence. Despite the wrapping of this very dry air around the storm, Helene intensified steadily to a Category 3 hurricane suggesting that the dry air was unable to significantly slow storm intensification. Several uncertainties remain about the role of the SAL in Helene (and in tropical cyclones in general). To better address these uncertainties, NASA will be conducting a three year airborne campaign called the Hurricane and Severe Storm Sentinel (HS3). The HS3 objectives are: To obtain critical measurements in the hurricane environment in order to identify the role of key factors such as large-scale wind systems (troughs, jet streams), Saharan air masses, African Easterly Waves and their embedded critical layers (that help to isolate tropical disturbances from hostile environments). To observe and understand the three-dimensional mesoscale and convective-scale internal structures of tropical disturbances and cyclones and their role in intensity change. The mission objectives will be achieved using

  14. The impact of limiting ocean roughness on GEOS-5 AGCM tropical cyclone forecasts

    NASA Astrophysics Data System (ADS)

    Molod, Andrea; Suarez, Max; Partyka, Gary

    2013-01-01

    Global climate models have been shown to simulate tropical cyclone-like behavior even at relatively coarse resolution, and recent higher resolution simulations more accurately capture the intensity, structure, and interannual variability. Even the highest resolution global models, however, continue to underestimate the intensity of the strongest tropical cyclones. The simulated cyclone intensity has been shown by many studies to be greatly influenced by the fluxes at the air-sea interface. A simple modification has been implemented in the GEOS-5 atmospheric general circulation model (AGCM) based on existing theory and laboratory experiments, which demonstrated that the ocean roughness does not increase with surface stress beyond some threshold. A series of strong tropical cyclone simulations were performed with the GEOS-5 AGCM to evaluate the impact of imposing a limit on ocean surface roughness at high wind speeds. The results demonstrated clear improvements in cyclone intensity and structure in the simulations with limited ocean roughness.

  15. Relative impact of climate indicators and aerosols on tropical cyclones

    NASA Astrophysics Data System (ADS)

    Chiacchio, Marc; Pausata, Francesco; Messori, Gabriele; Hannachi, Abdel; Chin, Mian; Ekman, Annica; Barrie, Leonard

    2015-04-01

    This study assesses the most important environmental variables modulating tropical cyclone (TC) frequency in six different oceanic basins such as the East Pacific, West Pacific, North Atlantic, North Indian Ocean, South Indian Ocean, and South Pacific. To determine their influence, we used multiple linear regression between TC frequency and variations in meteorological variables and circulation indices as well as aerosol optical depth (AOD) anomalies over the tropical cyclone development areas for the period 1980-2009 (where the AOD was separated into the compounds black and organic carbon, sulfate dust and sea salt). Overall the low-level relative humidity in the North Atlantic, stratospheric aerosol burden in the East Pacific, and the black carbon burden in the North Indian basin showed the greatest relation with TC activity and were all with statistically significant and explained variances of 28%. Amongst the circulation modes of variability, the Atlantic Multidecadal Oscillation (AMO) and the El Nino Southern Oscillation (ENSO) appeared to be most important to TC activity with significant variances of 29% in the South Indian Ocean and 25% in the East Pacific basins, respectively. We also examined the inter-basin relationship between the different environmental variables in one basin and the cyclone frequency in another basin. Overall the strongest connections were found between North Atlantic basin variables and North Indian TCs while the weakest links were found between West Pacific basin variables and South Pacific TCs. Lastly, because the strongest cooling of the lower stratospheric temperature was found over the North Atlantic since the last few decades and because the cooling could explain a variance of 15% of TC frequency in that same basin, we investigated five global climate models from the historical runs of the CMIP5 archive to determine whether they were able to capture this cooling in the lower stratosphere. Although the models were able to

  16. Upper Ocean Response to Tropical Cyclones in the Bay of Bengal

    NASA Astrophysics Data System (ADS)

    Shroyer, E.; Waterhouse, A. F.; St Laurent, L.; Moum, J. N.; Sharma, R.; Mahadevan, A.; Wijesekera, H. W.

    2016-02-01

    The upper ocean response to tropical cyclones is detailed using moored and shipboard observations collected in the Bay of Bengal during November - December 2013. Shipboard measurements were coincident with the passage of Cyclone Madi, a very severe cyclone with greater than 60 knot winds and rainfall rate in excess of 80 mm/hr. Cyclone Madi developed over the west central Bay before dissipating offshore of Sri Lanka in mid-December. Enhanced mixing and generation of near-inertial waves were observed as the cyclone intensified. The mixing signature, which included a reduction in upper ocean stratification, was notable 100s of kilometers from the cyclone center. Apart from the cyclone, the observed mixing in the Bay of Bengal was weak, suggesting a typically quiescent environment that may primarily experience significant turbulent mixing during isolated but intense events.

  17. A meridional dipole in premonsoon Bay of Bengal tropical cyclone activity induced by ENSO: TROPICAL CYCLONES, MONSOON AND ENSO

    SciTech Connect

    Balaguru, Karthik; Leung, L. Ruby; Lu, Jian; Foltz, Gregory R.

    2016-06-27

    Analysis of Bay of Bengal tropical cyclone (TC) track data for the month of May during 1980-2013 reveals a meridional dipole in TC intensification: TC intensification rates increased in the northern Bay and decreased in the southern Bay. The dipole was driven by an increase in low-level vorticity and atmospheric humidity in the northern Bay, making the environment more favorable for TC intensification, and enhanced vertical wind shear in the southern Bay, tending to reduce TC development. These environmental changes were associated with a strengthening of the monsoon circulation for the month of May, driven by a La Nin˜a-like shift in tropical Pacific SSTs andassociated tropical wave dynamics. Analysis of a suite of climate models fromthe CMIP5 archive for the 150-year historical period shows that most models correctly reproduce the link between ENSO and Bay of Bengal TC activity through the monsoon at interannual timescales. Under the RCP 8.5 scenario the same CMIP5 models produce an El Nin˜o like warming trend in the equatorial Pacific, tending to weaken the monsoon circulation. These results suggest

  18. Impacts of Different Grades of Tropical Cyclones on Infectious Diarrhea in Guangdong, 2005-2011

    PubMed Central

    Zhang, Ying; Wang, Wei; Wang, Xin; Jiang, Baofa; Ma, Wei

    2015-01-01

    Objective Guangdong province is one of the most vulnerable provinces to tropical cyclones in China. Most prior studies concentrated on the relationship between tropical cyclones and injuries and mortality. This study aimed to explore the impacts of different grades of tropical cyclones on infectious diarrhea incidence in Guangdong province, from 2005 to 2011. Methods Mann-Whitney U test was firstly used to examine if infectious diarrhea were sensitive to tropical cyclone. Then unidirectional 1:1 case-crossover design was performed to quantitatively evaluate the relationship between daily number of infectious diarrhea and tropical cyclone from 2005 to 2011 in Guangdong, China. Principal component analysis (PCA) was applied to eliminate multicollinearity. Multivariate logistic regression model was used to estimate the hazard ratios (HRs) and the 95% confidence intervals (CI). Results There were no significant relationships between tropical cyclone and bacillary dysentery, amebic dysentery, typhoid, and paratyphoid cases. Infectious diarrhea other than cholera, dysentery, typhoid and paratyphoid significantly increased after tropical cyclones. The strongest effect were shown on lag 1 day (HRs = 1.95, 95%CI = 1.22, 3.12) and no lagged effect was detected for tropical depression, tropical storm, severe tropical storm and typhoon, with the largest HRs (95%CI) of 2.16 (95%CI = 1.69, 2.76), 2.43 (95%CI = 1.65, 3.58) and 2.21 (95%CI = 1.65, 2.69), respectively. Among children below 5 years old, the impacts of all grades of tropical cyclones were strongest at lag 0 day. And HRs were 2.67 (95%CI = 1.10, 6.48), 2.49 (95%CI = 1.80, 3.44), 4.89 (95%CI = 2.37, 7.37) and 3.18 (95%CI = 2.10, 4.81), respectively. Conclusion All grades of tropical cyclones could increase risk of other infectious diarrhea. Severe tropical storm has the strongest influence on other infectious diarrhea. The impacts of tropical cyclones on children under 5 years old were higher than total population

  19. Impacts of different grades of tropical cyclones on infectious diarrhea in Guangdong, 2005-2011.

    PubMed

    Kang, Ruihua; Xun, Huanmiao; Zhang, Ying; Wang, Wei; Wang, Xin; Jiang, Baofa; Ma, Wei

    2015-01-01

    Guangdong province is one of the most vulnerable provinces to tropical cyclones in China. Most prior studies concentrated on the relationship between tropical cyclones and injuries and mortality. This study aimed to explore the impacts of different grades of tropical cyclones on infectious diarrhea incidence in Guangdong province, from 2005 to 2011. Mann-Whitney U test was firstly used to examine if infectious diarrhea were sensitive to tropical cyclone. Then unidirectional 1:1 case-crossover design was performed to quantitatively evaluate the relationship between daily number of infectious diarrhea and tropical cyclone from 2005 to 2011 in Guangdong, China. Principal component analysis (PCA) was applied to eliminate multicollinearity. Multivariate logistic regression model was used to estimate the hazard ratios (HRs) and the 95% confidence intervals (CI). There were no significant relationships between tropical cyclone and bacillary dysentery, amebic dysentery, typhoid, and paratyphoid cases. Infectious diarrhea other than cholera, dysentery, typhoid and paratyphoid significantly increased after tropical cyclones. The strongest effect were shown on lag 1 day (HRs = 1.95, 95%CI = 1.22, 3.12) and no lagged effect was detected for tropical depression, tropical storm, severe tropical storm and typhoon, with the largest HRs (95%CI) of 2.16 (95%CI = 1.69, 2.76), 2.43 (95%CI = 1.65, 3.58) and 2.21 (95%CI = 1.65, 2.69), respectively. Among children below 5 years old, the impacts of all grades of tropical cyclones were strongest at lag 0 day. And HRs were 2.67 (95%CI = 1.10, 6.48), 2.49 (95%CI = 1.80, 3.44), 4.89 (95%CI = 2.37, 7.37) and 3.18 (95%CI = 2.10, 4.81), respectively. All grades of tropical cyclones could increase risk of other infectious diarrhea. Severe tropical storm has the strongest influence on other infectious diarrhea. The impacts of tropical cyclones on children under 5 years old were higher than total population.

  20. Atlantic Warm Pool acting as a link between Atlantic Multidecadal Oscillation and Atlantic tropical cyclone activity

    NASA Astrophysics Data System (ADS)

    Wang, Chunzai; Lee, Sang-Ki; Enfield, David B.

    2008-05-01

    Multidecadal variability of Atlantic tropical cyclone activity is observed to relate to the Atlantic Multidecadal Oscillation (AMO), a mode manifesting primarily in sea surface temperature (SST) in the high latitudes of the North Atlantic. In the low latitudes of the North Atlantic, a large body of warm water called the Atlantic Warm Pool (AWP) comprises the Gulf of Mexico, the Caribbean Sea, and the western tropical North Atlantic. AWP variability occurs on both interannual and multidecadal timescales as well as with a secular variation. The AWP multidecadal variability coincides with the signal of the AMO; that is, the warm (cool) phases of the AMO are characterized by repeated large (small) AWPs. Since the climate response to the North Atlantic SST anomalies is primarily forced at the low latitudes and the AWP is in the path of or a birthplace for Atlantic tropical cyclones, the influence of the AMO on Atlantic tropical cyclone activity may operate through the mechanism of the AWP-induced atmospheric changes. The AWP-induced changes related to tropical cyclones that we emphasize here include a dynamical parameter of tropospheric vertical wind shear and a thermodynamical parameter of convective instability. More specifically, an anomalously large (small) AWP reduces (enhances) the vertical wind shear in the hurricane main development region and increases (decreases) the moist static instability of the troposphere, both of which favor (disfavor) Atlantic tropical cyclone activity. This is the most plausible way in which the AMO relationship with Atlantic tropical cyclones can be understood.

  1. NASA GPM Measures Tropical Cyclone 05S (Bohale), Dec. 9 2015

    NASA Image and Video Library

    On Dec. 9, 2015, NASA's Global Precipitation Measurement (GPM) mission measured thunderstorm tops reaching heights on Tropical Cyclone 05S (Bohale) above 16.6 km (10.3 miles) near the center of the...

  2. Tropical Cyclones: Forecasting Advances, Science Opportunities and Operational Challenges

    NASA Astrophysics Data System (ADS)

    Bosart, L. F.

    2014-12-01

    Although skill in forecasting the tracks of tropical cyclones (TCs) by operational forecast centers have improved steadily over the last 25 years, corresponding forecasts of TC intensity have shown little improvement until recently. These recent improvements in TC intensity forecasts appear to be related to a combination of better data assimilation, improved physics, and increased resolution in global operational numerical weather prediction models and new knowledge gained from a variety of recent TC-related field programs such as BGRIP, IFEX,and PREDICT. The first part of this presentation will briefly review the state of the art of TC track and intensity forecasting. The bulk of this presentation will address important TC-related science and operational challenges. These challenges include: 1) determining the physical processes that govern TC clustering, mutually interacting TCs, and the existence of different TC genesis pathways, 2) establishing how tropical-midlatitude interactions associated with recurving and transitioning (extratropical transition) TCs can trigger downstream baroclinic development, the subsequent formation of eastward-propagating Rossby wave trains, and the ensuing occurrence of extreme weather events well downstream, and 3) identifying critical TC-related forecast problems such as forecasts of the timing and extent of coastal storm surges and inland flooding associated with landfalling TCs). These important science and operational challenges will be illustrated with brief case studies.

  3. A Dynamical Initialization Scheme for Binary Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Liu, H.; Tan, Z. M.

    2015-12-01

    A dynamic initialization (DI) scheme for binary vortices (BVDI) is proposed to improve the initial conditions for the simulations of binary tropical cyclones (TCs) using the Weather Research and Forecasting (WRF) model. This BVDI scheme is based on a new hurricane/typhoon DI (HTDI) formulated for the single TC, which is a modification of the DI developed by Cha and Wang (2013) while further introduces the adjustment of initial vortex size and wet bogus vortex. Two TC cases, i.e., Super Typhoon Saomai (2006) and Tropical Storm Bopha (2006) in Western North Pacific, have been selected as a sample of binary TCs to test the performance of different DI schemes. The adjustment of initial vortex scale in HTDI makes improvements to the evolution of intensity and structure of Saomai. Moreover, the introduced wet bogus vortex ensures the spinning-up of Bopha's initial vortex. In addition, BVDI not only has the merits of HTDI, but also shows its advantage in reflecting the impact of the interaction on this pair of binary TCs within the initial condition. With that the tracks, intensities and structures as well as their evolutions (e.g. rapid intensification and concentric eyewall) of both Saomai and Bopha could be successfully captured comparing with the observations, which is advantage than other DI schemes. The results indicate that it is necessary to improve the representation of two TCs in the initial conditions and include their interactions in the binary TCs forecast.

  4. Statistical Detection of Anthropogenic Temporal Changes in the Distribution of Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Joannes-boyau, R.; Bodin, T.; Scheffers, A.; Sambridge, M.

    2012-12-01

    Recent studies highlighting the potential impact of climate change on tropical cyclones have added fuel to the already controversial debates. The link between climate change and tropical cyclone intensity and frequency has been disputed, as both appear to remain in the natural variability. The difficulty lies in our ability to distinguish natural changes from anthropogenic-induced anomalies. The increased anthropogenic atmospheric carbon dioxide leads to environmental changes such as warmer Sea Surface Temperatures (SST) and thus could impact tropical cyclones intensities and frequencies. However, recent studies show that, against an increasing SST, no global trend in respect to cyclone frequency has yet emerged. Scientists have warned to consider the heterogeneity of the existing dataset; especially since the historical tropical cyclone record is frequently accused to be incomplete. Given the abundance of cyclone record data and its likely sensitivity to a number of environmental factors, the real limitation comes from our ability to understand the record as a whole. Thus, strong arguments against the impartiality of proposed models are often debated. We will present an impartial and independent statistical tool applicable to a wide variety of physical and biological phenomena such as processes described by power laws, to observe temporal variations in the tropical cyclone track record from 1842 to 2010. This methodology allows us to observe the impact of anthropogenic-induced modifications on climatic events, without being clustered in subjective parameterised models.

  5. Tropical Cyclones Feed More Heavy Rain in a Warmer Climate

    NASA Technical Reports Server (NTRS)

    Lau, K.-M.; Zhou, Y. P.; Wu, H.-T.

    2007-01-01

    The possible linkage of tropical cyclones (TC) to global warming is a hotly debated scientific topic, with immense societal impacts. Most of the debate has been focused on the issue of uncertainty in the use of non-research quality data for long-term trend analyses, especially with regard to TC intensity provided by TC forecasting centers. On the other hand, it is well known that TCs are associated with heavy rain during the processes of genesis and intensification, and that there are growing evidences that rainfall characteristics (not total rainfall) are most likely to be affected by global warming. Yet, satellite rainfall data have not been exploited in any recent studies of linkage between tropical cyclones (TC) and global warming. This is mostly due to the large uncertainties associated with detection of long-term trend in satellite rainfall estimates over the ocean. This problem, as we demonstrate in this paper, can be alleviated by examining rainfall distribution, rather than rainfall total. This paper is the first to use research-quality, satellite-derived rainfall from TRMM and GPCP over the tropical oceans to estimate shift in rainfall distribution during the TC season, and its relationships with TCs, and sea surface temperature (SST) in the two major ocean basins, the northern Atlantic and the northern Pacific for 1979-2005. From the rainfall distribution, we derive the TC contributions to rainfall in various extreme rainfall categories as a function to time. Our results show a definitive trend indicating that TCs are contributing increasingly to heavier rain events, i.e., intense TC's are more frequent in the last 27 years. The TC contribution to top 5% heavy rain has nearly doubled in the last two decades in the North Atlantic, and has increased by about 10% in the North Pacific. The different rate of increase in TC contribution to heavy rain may be related to the different rates of different rate of expansion of the warm pool (SST >2S0 C) area in the

  6. Interdecadal variation of Korea affecting tropical cyclone intensity

    NASA Astrophysics Data System (ADS)

    Choi, Ki-Seon; Cha, Yu-Mi; Kang, Sung-Dae; Kim, Hae-Dong

    2015-05-01

    This study analyzed a time series of average central pressure of tropical cyclone (TC) that affected Korea in summer season from 1965 to 2012. To determine whether climate regime shift exists in this time series, statistical change-point analysis was applied to this time series. The result showed that significant climate regime shift existed in 1989, that is, TC intensity from 1965 to 1988 (6588) was weaker than that from 1989 to 2012 (8912). Therefore, an average difference between former and latter periods was analyzed to study large-scale environments, which caused such difference. While TC genesis frequency showed a tendency that TCs in the 6588 period were originated from the northwest quadrant in the tropical and subtropical western North Pacific, TCs in the 8912 period were originated from the southeast quadrant. Thus, it was judged that TCs in the 6588 were generated at a higher latitude followed by moving to Korea, so their strength was weaker than those of TCs of 8912 due to lack of time to acquire sufficient energy from the sea. For TC passage frequency, TCs in the 6588 period showed a tendency to move a short distance from the sea far away from the southeast in Japan to the sea far away from the northeast in Japan or toward the East China Sea. On the other hand, TCs in the 8912 period moved a longer distance from the sea far away from the Philippines via Japan to the eastern sea of Kamchatka Peninsular or toward the east region in China. As such, an average difference of intensity between the former period and the latter period over the 500-hPa streamline was analyzed to determine why the intensity of TCs in the 6588 period was weaker than that of TCs in the 8912 period. As a result, anomalous cold northerlies from anomalous cyclones based on the northern territory of Japan were predominant, while these anomalous flows were originated from the tropical and subtropical western Pacific followed by moving to Korea, thereby affecting the weakening of the TC

  7. Modeled dependence of wind and waves on ocean temperature in tropical cyclones

    NASA Astrophysics Data System (ADS)

    Phibbs, S.; Toumi, R.

    2015-12-01

    A coupled ocean-atmosphere-wave model is used to investigate the sensitivity of surface wind speed and significant wave height to ocean temperature for idealized tropical cyclones (TCs). More intense and larger TCs, with higher waves, form when ocean temperature is increased. The maximum significant wave height increases more than the maximum wind speed for TCs up to hurricane force wind. However, above hurricane force wind the change in maximum wind speed is similar or greater than the change in maximum significant wave height. This can be explained by the wind drag coefficient decreasing as wind speed exceeds hurricane force wind, so that the growth of waves is dampened. The areal footprint of wave height grows considerably more than the maximum as ocean temperature is increased. This suggests a large increase in the surface area of damaging waves generated by TCs may be the dominant impact of a future warmer ocean.

  8. Impact of subgrid-scale processes on eyewall replacement cycle of tropical cyclones in HWRF system

    NASA Astrophysics Data System (ADS)

    Zhu, Ping; Zhu, Zhenduo; Gopalakrishnan, Sundararaman; Black, Robert; Marks, Frank D.; Tallapragada, Vijay; Zhang, Jun A.; Zhang, Xuejin; Gao, Cen

    2015-11-01

    Two idealized simulations by the Hurricane Weather Research and Forecast (HWRF) model are presented to examine the impact of model physics on the simulated eyewall replacement cycle (ERC). While no ERC is produced in the control simulation that uses the operational HWRF physics, the sensitivity experiment with different model physics generates an ERC that possesses key features of observed ERCs in real tropical cyclones. Likely reasons for the control simulation not producing ERC include lack of outer rainband convection at the far radii from the eyewall, excessive ice hydrometeors in the eyewall, and enhanced moat shallow convection, which all tend to prevent the formation of a persistent moat between the eyewall and outer rainband. Less evaporative cooling from precipitation in the outer rainband region in the control simulation produces a more stable and dryer environment that inhibits the development of systematic convection at the far radii from the eyewall.

  9. Tropical cyclone/upper-atmospheric interaction as inferred from satellite total ozone observations

    SciTech Connect

    Rodgers, E.B.

    1992-01-01

    The Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) was used to map the distribution of total ozone within and surrounding western North Atlantic and North Pacific tropical cyclones that occurred from 1979-1982. It was found from numerical model simulations and diagnostics and satellite observations that the distribution of total ozone within the subtropical upper-tropospheric waves during the tropical cyclone season corresponded well with the variation of thermodynamic parameters (i.e., temperature, thickness, geopotential heights) near the tropopause and the regions of strong stratospheric and tropospheric exchange processes. These results are similar to previous middle latitudinal observations. It was also found that the three-dimensional transport processes associated with both the western North Atlantic and Pacific tropical cyclone's outflow jet induced secondary circulation and the strong vertical motions associated with active deep convective and eye regions helped to modify the total ozone distribution that is usually observed within these subtropical upper-tropospheric waves. The tropical cyclone induced modifications of the total ozone in the upper-tropospheric waves became greater as the tropical cyclone became more intense and the three-dimensional transpost processes associated with the outflow jet, convection and eye strengthened. The strong relationship between total ozone distribution and the variation of the tropopause topography, made it possible to use TOMS to monitor the propagation of the subtropical upper-tropospheric waves and the mutual adjustment between tropical cyclones and their upper-tropospheric and lower-stratospheric environment when these tropical cyclones and the upper-tropospheric waves interacted. These total ozone patterns during tropical cyclone and upper-tropospheric wave interaction reflected the three-dimensional upper-tropospheric transport processes that were conducive for storm intensification, weakening, or recurvature.

  10. Why Do Model Tropical Cyclones Intensify More Rapidly at Low Latitudes?

    DTIC Science & Technology

    2015-05-01

    low latitudes. The answer to this question touches on practically all facets of the dynamics and thermodynamics of tropical cyclones. The answer invokes...practically all facets of the dynamics and thermodynamics of tropical cyclones. The answer invokes the conventional spin-up mechanism, as articulated in...the dependence of the intensification rate and mature intensity on latitude touches on practically all facets of the dynamics and thermodynamics of

  11. Why Do Model Tropical Cyclones Grow Progressively in Size and Decay in Intensity after Reaching Maturity

    DTIC Science & Technology

    2015-08-17

    effect, inertial stability, intensity, rotating convection paradigm Date: August 17, 2015 1 Introduction When measured by the extent of gale-force...and intensity of the storm evolve progressively with time. In fact, according to the conventional paradigm for tropical cyclone intensification (see...the first page of his paper that “little is known about the mech- anism controlling (tropical cyclone: our insertion) size”. Nevertheless, we think

  12. Development of an Expert System Based on the Systematic Approach To Tropical Cyclone Track Forecasting

    DTIC Science & Technology

    2016-06-07

    assist the forecaster to accomplish each task. The formulation of an accurate TC forecast represents a highly complex information management problem that...1 Development Of An Expert System Based On The Systematic Approach To Tropical Cyclone Track Forecasting Lester E. Carr III Department of Meteorology...are to improve the quantitative accuracy and interpretative utility of official tropical cyclone (TC) track forecasts by enabling forecasters to

  13. Tropical Cyclone Report: Joint Typhoon Warning Center Guam, Mariana Islands, 1991

    DTIC Science & Technology

    1991-01-01

    Central Pacific Hurricane provided in the remarks section. Center (CPHC), Honolulu via the Naval Warnings in the western North Pacific Western...tropical cyclone that was warned on by three separate U.S. tropical cyclone warning centers. Enrique began in the Eastern Pacific, the National Hurricane ...Center’s area of responsibility, trekked 4900 nm (9100 kmn) across the North Pacific Ocean through the Central Pacific Hurricane Center’s area, then

  14. The importance of vegetation change in the prediction of future tropical cyclone flood statistics

    NASA Astrophysics Data System (ADS)

    Irish, J. L.; Resio, D.; Bilskie, M. V.; Hagen, S. C.; Weiss, R.

    2015-12-01

    Global sea level rise is a near certainty over the next century (e.g., Stocker et al. 2013 [IPCC] and references therein). With sea level rise, coastal topography and land cover (hereafter "landscape") is expected to change and tropical cyclone flood hazard is expected to accelerate (e.g., Irish et al. 2010 [Ocean Eng], Woodruff et al. 2013 [Nature], Bilskie et al. 2014 [Geophys Res Lett], Ferreira et al. 2014 [Coast Eng], Passeri et al. 2015 [Nat Hazards]). Yet, the relative importance of sea-level rise induced landscape change on future tropical cyclone flood hazard assessment is not known. In this paper, idealized scenarios are used to evaluate the relative impact of one class of landscape change on future tropical cyclone extreme-value statistics in back-barrier regions: sea level rise induced vegetation migration and loss. The joint probability method with optimal sampling (JPM-OS) (Resio et al. 2009 [Nat Hazards]) with idealized surge response functions (e.g., Irish et al. 2009 [Nat Hazards]) is used to quantify the present-day and future flood hazard under various sea level rise scenarios. Results are evaluated in terms of their impact on the flood statistics (a) when projected flood elevations are included directly in the JPM analysis (Figure 1) and (b) when represented as additional uncertainty within the JPM integral (Resio et al. 2013 [Nat Hazards]), i.e., as random error. Findings are expected to aid in determining the level of effort required to reasonably account for future landscape change in hazard assessments, namely in determining when such processes are sufficiently captured by added uncertainty and when sea level rise induced vegetation changes must be considered dynamically, via detailed modeling initiatives. Acknowledgements: This material is based upon work supported by the National Science Foundation under Grant No. CMMI-1206271 and by the National Sea Grant College Program of the U.S. Department of Commerce's National Oceanic and

  15. Epidemiology of injuries due to tropical cyclones in Hong Kong: a retrospective observational study.

    PubMed

    Rotheray, K R; Aitken, P; Goggins, W B; Rainer, T H; Graham, C A

    2012-12-01

    Tropical cyclones are huge circulating masses of wind which form over tropical and sub-tropical waters. They affect an average of 78 million people each year. Hong Kong is a large urban centre with a population of just over 7 million which is frequently affected by tropical cyclones. We aimed to describe the numbers and types of injuries due to tropical cyclones in Hong Kong, as well as their relation to tropical cyclone characteristics. The records of all patients presenting to Hong Kong's public hospital emergency departments from 1st January 2004 to 31st December 2009 with tropical cyclone related injuries were reviewed and information regarding patient and injury characteristics was collected. Meteorological records for the relevant periods were examined and data on wind speed, rainfall and timing of landfall and warning signals was recorded and compared with the timing of tropical cyclone related injuries. A total of 460 tropical cyclone related injuries and one fatality across 15 emergency departments were identified during the study period. The mean age of those injured was 48 years and 48% were female. 25.4% of injuries were work related. The head (33.5%) and upper limb (32.5%) were the most commonly injured regions, with contusions (48.6%) and lacerations (30.2%) being the most common injury types. Falls (42.6%) were the most common mechanism of injury, followed by being hit by a falling or flying object (22.0%). In univariable analysis the relative risk of injury increased with mean hourly wind speed and hourly maximum gust. Multivariable analysis, however, showed that relative risk of injury increased with maximum gust but not average wind speed, with relative risk of injury rising sharply above maximum gusts of greater than 20 m/s. Moderate wind speed with high gust (rather than high average and high gust) appears to be the most risky situation for injuries. Relative risk of injury was not associated with rainfall. The majority of injuries (56

  16. Advances in research and forecasting of tropical cyclones from 1963-2013

    NASA Astrophysics Data System (ADS)

    Elsberry, Russell L.

    2014-01-01

    A review of progress over the past 50 years in observing and forecasting of tropical cyclones is presented. Tremendous progress has been made in track forecasting in the past 20 years with the improvement in numerical model guidance and the use of consensus forecasting, and this has contributed to a number of warning centers now issuing five-day track forecasts that are as accurate as three-day forecasts of a decade ago. Techniques are now available to specify the track forecast uncertainty for assessing the risk of a tropical cyclone. With the advent of five-day forecasts, a focus on improved understanding of formation has led to two field experiments. A recent advance has been in extended-range (5-30 days) forecasts of tropical cyclone events (formations and tracks) in the western North Pacific from the ECMWF 32-day ensemble predictions. This advance is a contribution to a goal of seamless forecasting from one day to a season for tropical cyclones. Little progress has been made in intensity forecasting, although the Hurricane Forecast Improvement Project in the United States and recent field experiments may offer some future advances. Some advances in forecasting tropical cyclone impacts such as storm surge, surface waves, and precipitation have been achieved. Future opportunities for continued advances are possible such that improved warnings can lead to reductions in losses of lives and minimizing damages from tropical cyclones.

  17. Persistent northward North Atlantic tropical cyclone track migration over the past five centuries

    PubMed Central

    Baldini, Lisa M.; Baldini, James U. L.; McElwaine, Jim N.; Frappier, Amy Benoit; Asmerom, Yemane; Liu, Kam-biu; Prufer, Keith M.; Ridley, Harriet E.; Polyak, Victor; Kennett, Douglas J.; Macpherson, Colin G.; Aquino, Valorie V.; Awe, Jaime; Breitenbach, Sebastian F. M.

    2016-01-01

    Accurately predicting future tropical cyclone risk requires understanding the fundamental controls on tropical cyclone dynamics. Here we present an annually-resolved 450-year reconstruction of western Caribbean tropical cyclone activity developed using a new coupled carbon and oxygen isotope ratio technique in an exceptionally well-dated stalagmite from Belize. Western Caribbean tropical cyclone activity peaked at 1650 A.D., coincident with maximum Little Ice Age cooling, and decreased gradually until the end of the record in 1983. Considered with other reconstructions, the new record suggests that the mean track of Cape Verde tropical cyclones shifted gradually north-eastward from the western Caribbean toward the North American east coast over the last 450 years. Since ~1870 A.D., these shifts were largely driven by anthropogenic greenhouse gas and sulphate aerosol emissions. Our results strongly suggest that future emission scenarios will result in more frequent tropical cyclone impacts on the financial and population centres of the northeastern United States. PMID:27876831

  18. Persistent northward North Atlantic tropical cyclone track migration over the past five centuries

    SciTech Connect

    Baldini, Lisa M.; Baldini, James U. L.; McElwaine, Jim N.; Frappier, Amy Benoit; Asmerom, Yemane; Liu, Kam-biu; Prufer, Keith M.; Ridley, Harriet E.; Polyak, Victor; Kennett, Douglas J.; Macpherson, Colin G.; Aquino, Valorie V.; Awe, Jaime; Breitenbach, Sebastian F. M.

    2016-11-23

    Accurately predicting future tropical cyclone risk requires understanding the fundamental controls on tropical cyclone dynamics. Here we present an annually-resolved 450-year reconstruction of western Caribbean tropical cyclone activity developed using a new coupled carbon and oxygen isotope ratio technique in an exceptionally well-dated stalagmite from Belize. Western Caribbean tropical cyclone activity peaked at 1650 A.D., coincident with maximum Little Ice Age cooling, and decreased gradually until the end of the record in 1983. Considered with other reconstructions, the new record suggests that the mean track of Cape Verde tropical cyclones shifted gradually north-eastward from the western Caribbean toward the North American east coast over the last 450 years. Since ~1870 A.D., these shifts were largely driven by anthropogenic greenhouse gas and sulphate aerosol emissions. In conclusion, our results strongly suggest that future emission scenarios will result in more frequent tropical cyclone impacts on the financial and population centres of the northeastern United States.

  19. Persistent northward North Atlantic tropical cyclone track migration over the past five centuries

    DOE PAGES

    Baldini, Lisa M.; Baldini, James U. L.; McElwaine, Jim N.; ...

    2016-11-23

    Accurately predicting future tropical cyclone risk requires understanding the fundamental controls on tropical cyclone dynamics. Here we present an annually-resolved 450-year reconstruction of western Caribbean tropical cyclone activity developed using a new coupled carbon and oxygen isotope ratio technique in an exceptionally well-dated stalagmite from Belize. Western Caribbean tropical cyclone activity peaked at 1650 A.D., coincident with maximum Little Ice Age cooling, and decreased gradually until the end of the record in 1983. Considered with other reconstructions, the new record suggests that the mean track of Cape Verde tropical cyclones shifted gradually north-eastward from the western Caribbean toward the Northmore » American east coast over the last 450 years. Since ~1870 A.D., these shifts were largely driven by anthropogenic greenhouse gas and sulphate aerosol emissions. In conclusion, our results strongly suggest that future emission scenarios will result in more frequent tropical cyclone impacts on the financial and population centres of the northeastern United States.« less

  20. Persistent northward North Atlantic tropical cyclone track migration over the past five centuries.

    PubMed

    Baldini, Lisa M; Baldini, James U L; McElwaine, Jim N; Frappier, Amy Benoit; Asmerom, Yemane; Liu, Kam-Biu; Prufer, Keith M; Ridley, Harriet E; Polyak, Victor; Kennett, Douglas J; Macpherson, Colin G; Aquino, Valorie V; Awe, Jaime; Breitenbach, Sebastian F M

    2016-11-23

    Accurately predicting future tropical cyclone risk requires understanding the fundamental controls on tropical cyclone dynamics. Here we present an annually-resolved 450-year reconstruction of western Caribbean tropical cyclone activity developed using a new coupled carbon and oxygen isotope ratio technique in an exceptionally well-dated stalagmite from Belize. Western Caribbean tropical cyclone activity peaked at 1650 A.D., coincident with maximum Little Ice Age cooling, and decreased gradually until the end of the record in 1983. Considered with other reconstructions, the new record suggests that the mean track of Cape Verde tropical cyclones shifted gradually north-eastward from the western Caribbean toward the North American east coast over the last 450 years. Since ~1870 A.D., these shifts were largely driven by anthropogenic greenhouse gas and sulphate aerosol emissions. Our results strongly suggest that future emission scenarios will result in more frequent tropical cyclone impacts on the financial and population centres of the northeastern United States.

  1. Changes in North Atlantic Sea Surface Temperatures and Tropical Cyclones Activity

    NASA Astrophysics Data System (ADS)

    Andronache, C.; Phillips, V.

    2009-12-01

    The variability in the activity of North Atlantic tropical cyclones at seasonal scales, and beyond, has been linked to significant changes in the ocean - atmosphere system. The dominant factors affecting the development of North Atlantic tropical cyclones are: sea surface temperature (SST), surface pressure, atmospheric instability, humidity, and vertical shear of the mean flow. Changes in such factors at climate time-scales modulate the frequency of tropical cyclones and their most destructive manifestation, namely the hurricanes. Some of these changes have been observed to be linked to large-scale perturbations, such as ENSO, and other ocean - atmosphere oscillations and teleconnections. This study reports findings on changes in SST anomalies and their possible links to tropical cyclones. Using SST data over the last six decades, we illustrate statistical connections by applying novel mathematical techniques between the Atlantic Multi-decadal Oscillation (AMO) and tropical cyclones. Possible interactions between AMO, climate change and the fate of tropical cyclones are discussed in the context of recent advances in climate research.

  2. Persistent northward North Atlantic tropical cyclone track migration over the past five centuries

    NASA Astrophysics Data System (ADS)

    Baldini, Lisa M.; Baldini, James U. L.; McElwaine, Jim N.; Frappier, Amy Benoit; Asmerom, Yemane; Liu, Kam-Biu; Prufer, Keith M.; Ridley, Harriet E.; Polyak, Victor; Kennett, Douglas J.; MacPherson, Colin G.; Aquino, Valorie V.; Awe, Jaime; Breitenbach, Sebastian F. M.

    2016-11-01

    Accurately predicting future tropical cyclone risk requires understanding the fundamental controls on tropical cyclone dynamics. Here we present an annually-resolved 450-year reconstruction of western Caribbean tropical cyclone activity developed using a new coupled carbon and oxygen isotope ratio technique in an exceptionally well-dated stalagmite from Belize. Western Caribbean tropical cyclone activity peaked at 1650 A.D., coincident with maximum Little Ice Age cooling, and decreased gradually until the end of the record in 1983. Considered with other reconstructions, the new record suggests that the mean track of Cape Verde tropical cyclones shifted gradually north-eastward from the western Caribbean toward the North American east coast over the last 450 years. Since ~1870 A.D., these shifts were largely driven by anthropogenic greenhouse gas and sulphate aerosol emissions. Our results strongly suggest that future emission scenarios will result in more frequent tropical cyclone impacts on the financial and population centres of the northeastern United States.

  3. Power Law and Scaling in the Energy of Tropical Cyclones (Invited)

    NASA Astrophysics Data System (ADS)

    Corral, A.; Osso, A.; Llebot, J.

    2010-12-01

    The influence of climate variability and global warming on the occurrence of tropical cyclones is a controversial issue. Existing historical databases on the subject are not fully reliable, but a more fundamental hindrance is the lack of basic understanding regarding the intrinsic nature of tropical-cyclone genesis and evolution. It is known that tropical cyclones involve more than a passive response to changing external forcing, but it is not clear which dynamic behavior best describes them. We present an approach based on the application of the power dissipation index, which constitutes an estimation of released energy, to individual tropical cyclones. A robust law emerges for the statistics of power dissipation index, valid in four different ocean basins and over long time periods. In addition to suggesting a description of the physics of tropical cyclones in terms of critical phenomena, the scaling law enables us to quantify their response to changing climatic conditions, with an increase in the largest power dissipation index values with sea surface temperature or the presence of El Niño phenomena, depending on the basin under consideration. In this way, we demonstrate that the recent upswing in North Atlantic hurricane activity does not involve tropical cyclones that are quantitatively different from those in other sustained high-activity periods before 1970. A. Corral, A. Osso, and J.E. Llebot, Nature Phys. 2010.

  4. Tropical cyclone fullness: A new concept for interpreting storm intensity

    NASA Astrophysics Data System (ADS)

    Guo, Xi; Tan, Zhe-Min

    2017-05-01

    Intensity and size are two crucial factors in determining the destructiveness of a tropical cyclone (TC), but little is known about the relationship between them because of a lack of observations. TC fullness, a new concept, is proposed to quantitatively measure the storm wind structure, which is defined as the ratio of the extent of the outer-core wind skirt to the outer-core size of the TC. TC intensity is more strongly correlated with fullness than with other measures comprising just a single size parameter. A scale is introduced to classify TCs into four categories based on TC fullness (FS1 to FS4). Regardless of the specific inner-core and outer-core size, the FS4 fullness structure is necessary for an intense TC's development, while category FS1 and FS2 TCs are generally weak. Most major TCs achieve FS4 fullness structure earlier and more frequently than nonmajor TCs. Rapidly increasing fullness favors the intensification of TC.Plain Language Summary<span class="hlt">Tropical</span> <span class="hlt">cyclone</span> (TC) disasters caused tremendous property loss and casualties all over the world every year, while the knowledge on what essentially determines TC intensity is far beyond enough. Should a large TC ought to be intense and disastrous? And is a small TC doomed to be weak? It confused us when some dapper small TCs struck us with their fierce wind and torrential rain, while other large TCs that finally turned out to be a false alarm tricked us with their puffiness body. The underlying factor that truly controls TC intensity has been grasped here. We unveil the mysteries between TC intensity and size by raising a new concept: TC fullness. Either small or large TC can be intense; it depends on the fullness. TCs should possess FS4 fullness structure (high fullness) as long as they are intense; on the other hand, TCs with low fullness are weak in majority. In addition, rapidly increasing fullness is beneficial for the intensification of TC. The concept of TC</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT........75D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT........75D"><span>Environmental and internal controls of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensity change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Desflots, Melicie</p> <p></p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclone</span> (TC) intensity change is governed by internal dynamics and environmental conditions. This study aims to gain a better understanding of the physical mechanisms responsible for TC intensity changes with a particular focus to those related to the vertical wind shear and the impact of sea spray on the hurricane boundary layer, by using high resolution, full physics numerical simulations. The coupled model consists of three components: the non-hydrostatic, 5th generation Pennsylvania State University-NCAR mesoscale model (MM5), the NOAA/NCEP WAVEWATCH III (WW3) ocean surface wave model, and the WHOI three-dimensional upper ocean circulation model (3DPWP). Sea spray parameterizations (SSP) were developed at NOAA/ESRL, modified by the author and introduced in uncoupled and coupled simulations. The 0.5 km grid resolution MM5 simulation of Hurricane Lili showed a rapid intensification associated with a contracting eyewall. Hurricane Lili weakened in a 5-10 m s-1 vertical wind shear environment. The simulated storm experienced wind shear direction normal to the storm motion, which produced a strong wavenumber one rainfall asymmetry in the downshear-left quadrant of the storm. The increasing vertical wind shear induced a vertical tilt of the vortex with a time lag of 5-6 hours after the wavenumber one rainfall asymmetry was first observed in the model simulation. Other factors controlling intensity and intensity change in <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are the air-sea fluxes. Recent studies have shown that the momentum exchange coefficient levels off at high wind speed. However, the behavior of the exchange coefficient for enthalpy flux in high wind and the potential impact of sea spray on it is still uncertain. The current SSP are closely tied to wind speed and overestimate the mediated heat fluxes by sea spray in the hurricane boundary layer. As the sea spray generation depends on wind speed and the variable wave state, a new SSP based on the surface wave energy</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......317L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......317L"><span>Aerosols-Cloud-Microphysics Interactions in <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Earl</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luna-Cruz, Yaitza</p> <p></p> <p>Aerosols-cloud-microphysical processes are largely unknown in their influence on <span class="hlt">tropical</span> <span class="hlt">cyclone</span> evolution and intensification; aerosols possess the largest uncertainty. For example: What is the link between aerosols and cloud microphysics quantities? How efficient are the aerosols (i.e. dust from the Saharan Air Layer -SAL) as cloud condensation nuclei (CCN) and ice nuclei (IN)? Does aerosols affect the vertical velocity, precipitation rates, cloud structure and lifetime? What are the dominant factors and in which sectors of the <span class="hlt">tropical</span> <span class="hlt">cyclone</span>? To address some of the questions in-situ microphysics measurements from the NASA DC-8 aircraft were obtained during the Genesis and Rapid Intensification Processes (GRIP) 2010 field campaign. A total of four named storms (Earl, Gaston, Karl and Mathew) were sampled. Earl presented the excellent opportunity to study aerosols-cloud-microphysics interactions because Saharan dust was present and it underwent rapid intensification. This thesis seeks to explore hurricane Earl to develop a better understanding of the relationship between the SAL aerosols and cloud microphysics evolution. To assist in the interpretation of the microphysics observations, high resolution numerical simulations of hurricane Earl were performed using the Weather Research and Forecasting (WRF-ARW) model with the new Aerosol-Aware bulk microphysics scheme. This new version of Thompson scheme includes explicit activation of cloud condensation nuclei (CCN) from a major CCN source (i.e. sulfates and sea salt) and explicit ice nucleation (IN) from mineral dust. Three simulations are performed: (1) the Control case with the old Thompson scheme and initial conditions from GFS model, (2) the Aerosol-Aware first baseline case with GOCART aerosol module as an input conditions, and (3) the Aerosol-Aware increase case in which the GOCART aerosols concentrations were increased significantly. Overall, results of model simulations along with aircraft observations</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......421S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......421S"><span>Diabatic and frictional forcing effects on the structure and intensity of <span class="hlt">tropical</span> <span class="hlt">cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Slocum, Christopher J.</p> <p></p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclone</span> intensity forecasting skill has slowed in improvement for both dynamical and statistical-dynamical forecasting methods in comparison to gains seen in track forecasting skill. Also, forecast skill related to rapid intensification, e.g. a 30 kt or greater increase in intensity within a 24-hour period, still remains poor. In order to make advances and gain a greater understanding, the processes that affect intensity change, especially rapid intensification, need further study. This work evaluates the roles of diabatic and frictional forcing on the structure and intensity of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. To assess the diabatic forcing effects on intensity change in <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, this study develops applications of Eliassen's balanced vortex model to obtain one-dimensional solutions to the geopotential tendency and two-dimensional solutions to the transverse circulation. The one-dimensional balanced solutions are found with dynamical model outputs as well as aircraft reconnaissance combined with diabatic heating derived from microwave rainfall rate retrievals. This work uses solutions from both datasets to make short-range intensity predictions. The results show that for the one-dimensional solutions, the tangential tendency does not match the dynamical model or aircraft wind tendencies. To relax the assumptions of the one-dimensional solutions to the geopotential tendency, solutions for <span class="hlt">idealized</span> vortices are examined by finding two-dimensional solutions to the transverse circulation. The two-dimensional solutions allow for evaluation of the axisymmetric structure of the vortex on the (r, z)-plane without setting the baroclinicity to zero and the static stability to a constant value. While the sensitivity of tangential wind tendency to diabatic forcing and the region of high inertial stability is more realistic in the two-dimensional results, the solutions still neglect the influence of friction from the boundary layer. To understand further the role of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA155034','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA155034"><span>Forecasting of <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Motion Using an EOF (Empirical Orthogonal Function) Representation of Wind Forcing.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1984-12-01</p> <p>1981) studied the performance characteristics of various <span class="hlt">tropical</span> <span class="hlt">cyclone</span> movement prediction models in oeraticnal use at the National Hurricane ...<span class="hlt">tropical</span> cyc one intensity changes during FGGE. Postprints, 15th Conferenceon Hurricanes and <span class="hlt">Tropical</span> Meteorology, January 9-13, Miami, Florida, 224-231...1978: Reply. Journal of A lpied leteorolo4Z, 17, 19-420. Gray, ?. M., 1979: Hurricanes : their formation, structure and likely role in the <span class="hlt">tropical</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CorRe..35..613W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CorRe..35..613W"><span>Temporal clustering of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> on the Great Barrier Reef and its ecological importance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wolff, Nicholas H.; Wong, Aaron; Vitolo, Renato; Stolberg, Kristin; Anthony, Kenneth R. N.; Mumby, Peter J.</p> <p>2016-06-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> have been a major cause of reef coral decline during recent decades, including on the Great Barrier Reef (GBR). While <span class="hlt">cyclones</span> are a natural element of the disturbance regime of coral reefs, the role of temporal clustering has previously been overlooked. Here, we examine the consequences of different types of <span class="hlt">cyclone</span> temporal distributions (clustered, stochastic or regular) on reef ecosystems. We subdivided the GBR into 14 adjoining regions, each spanning roughly 300 km, and quantified both the rate and clustering of <span class="hlt">cyclones</span> using dispersion statistics. To interpret the consequences of such <span class="hlt">cyclone</span> variability for coral reef health, we used a model of observed coral population dynamics. Results showed that clustering occurs on the margins of the <span class="hlt">cyclone</span> belt, being strongest in the southern reefs and the far northern GBR, which also has the lowest <span class="hlt">cyclone</span> rate. In the central GBR, where rates were greatest, <span class="hlt">cyclones</span> had a relatively regular temporal pattern. Modelled dynamics of the dominant coral genus, Acropora, suggest that the long-term average cover might be more than 13 % greater (in absolute cover units) under a clustered <span class="hlt">cyclone</span> regime compared to stochastic or regular regimes. Thus, not only does <span class="hlt">cyclone</span> clustering vary significantly along the GBR but such clustering is predicted to have a marked, and management-relevant, impact on the status of coral populations. Additionally, we use our regional clustering and rate results to sample from a library of over 7000 synthetic <span class="hlt">cyclone</span> tracks for the GBR. This allowed us to provide robust reef-scale maps of annual <span class="hlt">cyclone</span> frequency and <span class="hlt">cyclone</span> impacts on Acropora. We conclude that assessments of coral reef vulnerability need to account for both spatial and temporal <span class="hlt">cyclone</span> distributions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26ES...47a2024H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26ES...47a2024H"><span>Modelling <span class="hlt">tropical</span> <span class="hlt">cyclone</span> hazards under climate change scenario using geospatial techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoque, M. A.; Phinn, S.; Roelfsema, C.; Childs, I.</p> <p>2016-11-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> are a common and devastating natural disaster in many coastal areas of the world. As the intensity and frequency of <span class="hlt">cyclones</span> will increase under the most likely future climate change scenarios, appropriate approaches at local scales (1-5 km) are essential for producing sufficiently detailed hazard models. These models are used to develop mitigation plans and strategies for reducing the impacts of <span class="hlt">cyclones</span>. This study developed and tested a hazard modelling approach for <span class="hlt">cyclone</span> impacts in Sarankhola upazila, a 151 km2 local government area in coastal Bangladesh. The study integrated remote sensing, spatial analysis and field data to model <span class="hlt">cyclone</span> generated hazards under a climate change scenario at local scales covering < 1000 km2. A storm surge model integrating historical <span class="hlt">cyclone</span> data and Digital Elevation Model (DEM) was used to generate the <span class="hlt">cyclone</span> hazard maps for different <span class="hlt">cyclone</span> return periods. Frequency analysis was carried out using historical <span class="hlt">cyclone</span> data (1960--2015) to calculate the storm surge heights of 5, 10, 20, 50 and 100 year return periods of <span class="hlt">cyclones</span>. Local sea level rise scenario of 0.34 m for the year 2050 was simulated with 20 and 50 years return periods. Our results showed that <span class="hlt">cyclone</span> affected areas increased with the increase of return periods. Around 63% of study area was located in the moderate to very high hazard zones for 50 year return period, while it was 70% for 100 year return period. The climate change scenarios increased the <span class="hlt">cyclone</span> impact area by 6-10 % in every return period. Our findings indicate this approach has potential to model the <span class="hlt">cyclone</span> hazards for developing mitigation plans and strategies to reduce the future impacts of <span class="hlt">cyclones</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ClDy...46.1277M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ClDy...46.1277M"><span>Reconciling droughts and landfalling <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in the Southeastern United States</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Misra, Vasubandhu; Bastola, Satish</p> <p>2016-02-01</p> <p>A popular perception is that landfalling <span class="hlt">tropical</span> <span class="hlt">cyclones</span> help to mitigate droughts in the Southeastern United States (SeUS). However intriguing paradigms on the role of large scale SST variations on continental US including SeUS droughts and seasonal Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity confronts us. These paradigms suggest that in the presence of warm (cold) eastern <span class="hlt">tropical</span> Pacific and cold (warm) Atlantic Ocean sea surface temperature anomaly (SSTA) lead to the increased likelihood of wetter (drier) conditions over the continental US including the SeUS. Juxtaposing this understanding with the fact that landfalling <span class="hlt">tropical</span> <span class="hlt">cyclones</span> contribute significantly to the annual mean total rainfall in the SeUS and in El Niño (La Niña) years with cold (warm) <span class="hlt">tropical</span> Atlantic SSTA lead to reduced (increased) Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity raises a conflict on the role of the large-scale SST variations in SeUS hydroclimate. This study attempts to investigate the apparent dichotomous role of the large scale SST variations on the SeUS hydrology by examining the role of rainfall from landfalling <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in the SeUS to local seasonal droughts. Our study finds that the contribution of the rainfall from landfalling <span class="hlt">tropical</span> <span class="hlt">cyclone</span> on the mitigation of monthly drought in the 28 SeUS watersheds is relatively insignificant. So much so that the hydrological model uncertainty in estimating the drought index over the 28 SeUS watersheds is larger than the sensitivity exhibited by the drought index to the inclusion of rain from landfalling <span class="hlt">tropical</span> <span class="hlt">cyclone</span>. The conclusions of this study are justified by the fact that the timing of the landfalling <span class="hlt">tropical</span> <span class="hlt">cyclone</span> in relation to overall soil moisture conditions of the watershed does not coincide with a drought like situation in the 1948-2006 time period analyzed in this study. This largely stems from the fact that the large-scale flow pattern resulting in abundant (lack of) advection of moisture for anomalously wet (dry</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A23C0319S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A23C0319S"><span>The Effect of Saharan Dust on North Atlantic Hydroclimate and <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> in a High-Resolution GCM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strong, J. D.; Vecchi, G. A.</p> <p>2015-12-01</p> <p>Climate of the <span class="hlt">tropical</span> North Atlantic and West Africa is sensitive to dust optical properties as shown by our previous work (Strong et al., 2015) using a fully coupled global climate model (GCM). However, that study was limited by the relatively coarse resolution of the GCM which could not resolve explicitly sub-scale processes important to the simulation of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs).Using simulations with the higher resolution, fully coupled GFDL Climate Model 2.5, Forecast-oriented Low Ocean Resolution version (CM2.5-FLOR), for several realistic sets of optical properties, we investigate the climatic response across the <span class="hlt">tropical</span> Atlantic basin to an <span class="hlt">idealized</span> aerosol radiative forcing from Saharan-born mineral dust, comparable to the observed changes between the 1960s and 1990s, with a focus on the hydrological cycle and TCs. CM2.5-FLOR has a higher resolution atmosphere which is able to resolve TCs and has been shown to accurately reproduce the observed <span class="hlt">tropical</span> <span class="hlt">cyclone</span> climatology.In the first part, we will show that the sign of the radiative response at the top of the atmosphere (ToA) changes between the more absorbing dust and more scattering dust simulations, in agreement with previous studies. Conversely, the radiative response at the surface is generally comparable between sets of optical properties. These differences result in opposing regional hydrologic and thermodynamic effects of dust both in the atmosphere and in the upper ocean. In the second part, the effect of Saharan-born mineral dust on TCs will be analyzed. In all simulations, dust causes a decrease in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity in the North Atlantic with the largest response occurring in the most absorbing and scattering optical regimes. We also note significant changes in the West Pacific in these simulations. The changes in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity are found to not be explained by common genesis potential indexes, but a relationship between accumulated <span class="hlt">cyclone</span> energy and ToA radiative flux</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A23E0328H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A23E0328H"><span>The Role of Interacting <span class="hlt">Cyclones</span> in Modifying <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Landfall Threat: Fujiwhara vs. enhanced Beta drift?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hart, R. E.</p> <p>2013-12-01</p> <p>The recent impacts of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs) Irene and Sandy have brought to the forefront the question of the true return period of landfalls in that region. Given the relatively short period of record of observations, those seeking robust return estimates often generate stochastic event sets. While the details of methods for generating those sets are generally not published (with an exception being Emanuel 2006), presentations have suggested that each member (TC event) of a stochastic set does not impact other TC members. Such an approach has the benefit of relative simplicity as well as rapidity of production, as each TC member can be produced without concern about simultaneous TCs in the basin. Given most real-world TCs are separated by several days or more, and distances of 2000km or more, this approach is seemingly well-founded for the majority of TC climatology. Yet, there have been many examples of TC-TC Fujiwhara interaction across the globe. While the interaction is much more common in the western Pacific, it is not unheard of in the Atlantic - with Connie and Diane in 1955 as two examples of such interaction but largely away from land. Further, the northeast U.S. coast can be threatened through such TC-TC interactions. The historic 1893 New York City Hurricane took an unusual NNW track (and landfall location) possibly as a consequence of interaction with one if not two additional nearby TCs. Numerical model (WRF) simulations of this case revealed exceptional difficulty in track prediction, illustrating further the complexity of the interaction. Interaction is not necessarily limited to another TC. Occasionally, a TC will interact with an occluded cold-core <span class="hlt">cyclone</span>, which can then take the TC on a highly unusual track. Such interactions by their nature occur most often early or late in the TC season. Examples of TC-nonTC interaction include the 1938 New England Hurricane, Hurricane Hazel from 1950, and most recently, Hurricane Sandy, all of which had</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..120.9173J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..120.9173J"><span>Effects of thermodynamic profiles on the interaction of binary <span class="hlt">tropical</span> <span class="hlt">cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jang, Wook; Chun, Hye-Yeong</p> <p>2015-09-01</p> <p>The interactions between <span class="hlt">idealized</span> binary <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs) on f and β planes with different separation distance and thermodynamic soundings obtained from the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data averaged over the western North Pacific are investigated through ensemble three-dimensional numerical simulations with a horizontal resolution of 10 km in a single domain. In the simulations on the f plane, two TCs show mutual <span class="hlt">cyclonic</span> rotations with symmetric structures. Two TCs with thermodynamic profiles of larger convective available potential energy (CAPE) and maximum potential intensity (MPI) show greater interaction than those with a smaller CAPE and MPI due to the stronger tangential velocity near the TC center. In the simulations on the β plane, the two TCs do not merge, because the beta effect prevents the attraction of the two TCs by generating asymmetric motions of the TC with northwestward forcing. The relative strengths of the two TCs change with time and depend on the low-level inflow influenced by the Coriolis parameter. Similar to the results on the f plane, the two TCs only merge with the thermodynamic soundings of large CAPE and MPI.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.U51C..02M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.U51C..02M"><span>Tree-ring Oxygen Isotope Records of Climate Modes Influencing North Atlantic <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mora, C. I.; Miller, D. L.; Grissino-Mayer, H. D.; Kocis, W. N.; Lewis, D. B.</p> <p>2006-12-01</p> <p>The relatively short instrumental record hinders our ability to discern the linkages between low frequency modes of climate variability and <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity and to differentiate natural versus anthropogenic components of these trends. The development of biological proxies for <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity and climate provides a basis for evaluation of these linkages over much longer time frames. The oxygen isotope composition of tree-ring cellulose, sampled at high resolution (seasonal or better), provides a new proxy for <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity that preserves a concurrent isotope time series reflecting the influence of climate variability. This proxy archive potentially extends many centuries beyond the instrumental and historical (documentary) record of climate and <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity. Isotope time series for longleaf pines (Pinus palustris Mill.) in southern Georgia and South Carolina preserve distinct <span class="hlt">tropical</span> <span class="hlt">cyclone</span> histories, yet similar, long term trends in cellulose δ 18O compositions. The isotope time series correlate to various climate modes proposed to impact hurricane formation and frequency. Tree-ring cellulose δ 18O values at the Georgia study site show a significant negative correlation with AMO indices from 1875 to about 1950, and a weaker, positive correlation from about 1965 to 1990. The "crossover" parallels a change in the predominant ontogeny of North Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclones</span> from <span class="hlt">tropical</span>-only to baroclinically-enhanced hurricanes. The intervening 1950s is marked by greater correspondence to ENSO indices. Reduced seasonality in the isotope record (i.e., the difference between earlywood and latewood δ 18O values) corresponds to warm phases of the PDO. An isotope series for 1580 to 1650 suggests little <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity coinciding with a period (1560-1625) of severe drought in the African Sahel. Although preliminary, these results suggest that tree-ring oxygen isotope compositions are sensitive to changes in climate</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A33P..05P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A33P..05P"><span>CYGNSS Observations of Surface Wind Speeds in Oceanic <span class="hlt">Tropical</span> and Extratropical <span class="hlt">Cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Posselt, D. J.; Crespo, J.; Naud, C. M.</p> <p>2016-12-01</p> <p>The <span class="hlt">Cyclone</span> Global Navigation Satellite System (CYGNSS) mission is the first of the new generation of NASA Earth Venture missions, and consists of a constellation of eight small satellites scheduled for launch in November 2016. The mission utilizes GPS signals reflected from the Earth's surface to infer near-surface wind speeds over the global <span class="hlt">tropical</span> oceans. The eight-satellite constellation will observe ocean-surface wind speeds in all weather conditions (including in heavy precipitation) with a median revisit time of approximately 3 hours. While CYGNSS is designed to measure wind speeds in the inner core of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, it will observe near-surface winds over all oceanic regions within the span of its orbit. The orbit inclination is 35 degrees, which means that the satellite will observe primarily the <span class="hlt">tropics</span> and sub-<span class="hlt">tropics</span>; however, because the antennae are angled 28 degrees off-nadir, the effective range of latitudes spans -40 to 40 degrees. As such, CYGNSS will observe regions known to be characterized by rapid extratropical <span class="hlt">cyclone</span> development (e.g., the southern portion of the Gulf Stream off the U.S. East Coast). In this presentation, we discuss CYGNSS sampling characteristics, with an eye toward its potential to observe winds not only in <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, but in extratropical <span class="hlt">cyclones</span> as well. We simulate orbits over a historical extratropical storm, and also utilize a multi-year database of <span class="hlt">cyclone</span> centers to determine CYGNSS sampling characteristics integrated over many storms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820011906','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820011906"><span>Monitoring <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensity using wind fields derived from short-interval satellite images</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rodgers, E. B.; Gentry, R. C.</p> <p>1981-01-01</p> <p>Rapid scan visible images from the Visible Infrared Spin Scan Radiometer sensor on board SMS-2 and GOES-1 were used to derive high resolution upper and lower tropospheric environmental wind fields around three western Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (1975-78). These wind fields were used to derive upper and lower tropospheric areal mean relative vorticity and their differences, the net relative angular momentum balance and upper tropospheric mass outflow. These kinematic parameters were shown by studies using composite rawinsonde data to be strongly related to <span class="hlt">tropical</span> <span class="hlt">cyclone</span> formation and intensity changes. Also, the role of forced synoptic scale subsidence in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> formation was examined. The studies showed that satellite-derived lower and upper tropospheric wind fields can be used to monitor and possibly predict <span class="hlt">tropical</span> <span class="hlt">cyclone</span> formation and intensity changes. These kinematic analyses showed that future changes in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensity are mainly related to the "spin-up" of the storms by the net horizontal transport of relative angular momentum caused by convergence of <span class="hlt">cyclonic</span> vorticity in the lower troposphere and to a lesser extent the divergence of anticyclone vorticity in the upper troposphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GGG....14.3632F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GGG....14.3632F"><span>Masking of interannual climate proxy signals by residual <span class="hlt">tropical</span> <span class="hlt">cyclone</span> rainwater: Evidence and challenges for low-latitude speleothem paleoclimatology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frappier, Amy Benoit</p> <p>2013-09-01</p> <p>The anomalously low oxygen isotope ratio (δ18O values) of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> rainfall can transfer proxy information about past <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity to stalagmite oxygen isotope records. Isotopically distinct stormwater reaches the growing crystal surface as a coherent slug, or after attenuation by mixing with isotopically normal vadose groundwaters. A high-resolution micromilled stalagmite stable isotope record from Belize shows that residual <span class="hlt">tropical</span> <span class="hlt">cyclone</span> water from Hurricane Mitch masked the oxygen isotope record of a major El Niño event. On decadal time scales, measured δ18O values are affected by changes in local <span class="hlt">tropical</span> <span class="hlt">cyclone</span> frequency. Despite the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> masking effect, the structure of the "missing" El Niño event is preserved in the ATM-7 carbon isotope ratios (δ13C values). In <span class="hlt">tropical</span> <span class="hlt">cyclone</span>-prone regions, the fidelity of stalagmite oxygen isotope proxy data to recording background climate signals is modulated by temporal variations in local <span class="hlt">tropical</span> <span class="hlt">cyclone</span> rainfall, and the sensitivity of individual stalagmites to <span class="hlt">tropical</span> <span class="hlt">cyclone</span> masking varies with hydrology. Speleothem δ13C values, unaffected by <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, can preserve the underlying structure of climatic variability. For low-latitude speleothems with C-O isotope covariance, intervals in which the δ18O values are significantly lower than δ13C values predict may indicate periods when local <span class="hlt">tropical</span> <span class="hlt">cyclone</span> masking of isotope-derived precipitation records is enhanced by greater infiltration of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> rain. The temporal structure in stalagmite C-O isotope covariance has paleoenvironmental meaning that may be revealed by exploring factors associated with independent behavior in each isotope ratio, respectively. <span class="hlt">Tropical</span> <span class="hlt">cyclone</span> masking presents new challenges to paleoclimatology and a source of hypotheses for paleotempestology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GBioC..30..767M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GBioC..30..767M"><span>Global impact of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> on primary production</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Menkes, Christophe E.; Lengaigne, Matthieu; Lévy, Marina; Ethé, Christian; Bopp, Laurent; Aumont, Olivier; Vincent, Emmanuel; Vialard, Jérôme; Jullien, Swen</p> <p>2016-05-01</p> <p>In this paper, we explore the global responses of surface temperature, chlorophyll, and primary production to <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs). Those ocean responses are first characterized from the statistical analysis of satellite data under ~1000 TCs over the 1998-2007 period. Besides the cold wake, the vast majority of TCs induce a weak chlorophyll response, with only ~10% of induced blooms exceeding 0.1 mg m-3. The largest chlorophyll responses mostly occur within coastal regions, in contrast to the strongest cold wakes that generally occur farther offshore. To understand this decoupling, we analyze a coupled dynamical-biogeochemical oceanic simulation forced by realistic wind vortices applied along observed TC tracks. The simulation displays a realistic spatial structure of TC-induced blooms and its observed decoupling with TC cold wakes. In regions of strong TC energy input, the strongest cold wakes occur in regions of shallow thermocline (<60 m) and the strongest blooms in regions of shallow nitracline and/or subsurface chlorophyll maximum (<60 m). Shallow thermoclines are found over many open ocean regions, while regions of shallow nitracline and/or subsurface chlorophyll maximum are most prominent in near-coastal areas, explaining the spatial decoupling between the cold and bloom wakes. The overall TC contribution to annual primary production is weak and amounts to ~1%, except in a few limited areas (east Eurasian coast, South <span class="hlt">tropical</span> Indian Ocean, Northern Australian coast, and Eastern Pacific Ocean in the TC-prone region) where it can locally reach up to 20-30%. Nearly 80% of this TC-induced annual primary production is the result of the biogeochemical response to the 30% strongest TCs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007Geo....35..111B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007Geo....35..111B"><span>Stalagmite stable isotope record of recent <span class="hlt">tropical</span> <span class="hlt">cyclone</span> events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Benoit Frappier, Amy; Sahagian, Dork; Carpenter, Scott J.; González, Luis A.; Frappier, Brian R.</p> <p>2007-02-01</p> <p>We present a 23 yr stalagmite record (1977 2000) of oxygen isotope variation, associated with 11 <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs), from Actun Tunichil Muknal cave in central Belize. High-resolution microsampling yielded a record of monthly to weekly temporal resolution that contains abrupt decreases (negative excursions) in calcite δ18O values that correspond with recent TC rain events nearby. A logistic discriminant model reliably identified TC proxy signals using the measurable parameters δ18O and δ13C values, and single point changes in δ18O value. The logistic model correctly identified 80% of excursions as TC events and incorrectly classified only 1 of nearly 1200 nonstorm sampling points. In addition to enabling high-resolution TC frequency reconstruction, this geologic proxy also provides information about the intensity of individual TCs. A multiple regression predicted TC intensity (R2 = 0.465, p = 0.034) using sampling frequency and excursion amplitude. Consistent with previous low-resolution studies, we found that the decadal average δ18O value was lower during the 1990s when several TCs produced rainfall in the area, but higher during the 1980s when only one TC struck. Longer, accurately dated, high-resolution speleothem stable isotope records may be a useful new tool for paleotempestology, to clarify associations between highly variable TC activity and the dynamic range of Quaternary climate.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACPD...1516111W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACPD...1516111W"><span>Impact of environmental moisture on <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, L.; Su, H.; Fovell, R. G.; Dunkerton, T. J.; Wang, Z.; Kahn, B. H.</p> <p>2015-06-01</p> <p>The impacts of environmental moisture on the intensification of a <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) are investigated in the Weather Research and Forecasting (WRF) model, with a focus on the azimuthal asymmetry of the moisture impacts. A series of sensitivity experiments with varying moisture perturbations in the environment are conducted and the Marsupial Paradigm framework is employed to understand the different moisture impacts. We find that modification of environmental moisture has insignificant impacts on the storm in this case unless it leads to convective activity in the environment, which deforms the quasi-Lagrangian boundary of the storm. By facilitating convection and precipitation outside the storm, enhanced environmental moisture ahead of the northwestward-moving storm induces a dry air intrusion to the inner core and limits TC intensification. However, increased moisture in the rear quadrants favors intensification by providing more moisture to the inner core and promoting storm symmetry, with primary contributions coming from moisture increase in the boundary layer. The different impacts of environmental moisture on TC intensification are governed by the relative locations of moisture perturbations and their interactions with the storm Lagrangian structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACP....1514041W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACP....1514041W"><span>Impact of environmental moisture on <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, L.; Su, H.; Fovell, R. G.; Dunkerton, T. J.; Wang, Z.; Kahn, B. H.</p> <p>2015-12-01</p> <p>The impacts of environmental moisture on the intensification of a <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) are investigated in the Weather Research and Forecasting (WRF) model, with a focus on the azimuthal asymmetry of the moisture impacts relative to the storm path. A series of sensitivity experiments with varying moisture perturbations in the environment are conducted and the Marsupial Paradigm framework is employed to understand the different moisture impacts. We find that modification of environmental moisture has insignificant impacts on the storm in this case unless it leads to convective activity that deforms the quasi-Lagrangian boundary of the storm and changes the moisture transport into the storm. By facilitating convection and precipitation outside the storm, enhanced environmental moisture ahead of the northwestward-moving storm induces a dry air intrusion to the inner core and limits TC intensification. In contrast, increased moisture in the rear quadrants favors intensification by providing more moisture to the inner core and promoting storm symmetry, with primary contributions coming from moisture increase in the boundary layer. The different impacts of environmental moisture on TC intensification are governed by the relative locations of moisture perturbations and their interactions with the storm Lagrangian structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MAP...128..545W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MAP...128..545W"><span>The inner core thermodynamics of the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> boundary layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Williams, Gabriel J.</p> <p>2016-10-01</p> <p>Although considerable progress has been made in understanding the inner-core dynamics of the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> boundary layer (TCBL), our knowledge of the inner-core thermodynamics of the TCBL remains limited. In this study, the inner-core budgets of potential temperature (θ), specific humidity ( q), and reversible equivalent potential temperature (θ _e) are examined using a high-resolution multilevel boundary layer model. The potential temperature budgets show that the heat energy is dominated by latent heat release in the eyewall, evaporative cooling along the outer edge of the eyewall, and upward surface fluxes of sensible and latent heat from the underlying warm ocean. It is shown that the vertical θ advection overcompensates the sum of radial advective warming from the boundary layer outflow jet and latent heating for the development of cooling in the eyewall within the TCBL. The moisture budgets show the dominant upward transport of moisture in the eyewall updrafts, partly by the boundary-layer outflow jet from the bottom eye region, so that the eyewall remains nearly saturated. The θ _e budgets reveal that the TCBL is maintained thermodynamically by the upward surface flux of higher-θ _e air from the underlying warm ocean, the radial transport of low-θ _e air from the outer regions of the TCBL, and the dry adiabatic cooling associated by eyewall updrafts. These results underscore the significance of vertical motion and the location of the boundary layer outflow jet in maintaining the inner core thermal structure of the TCBL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC24C..09T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC24C..09T"><span>Quantification of Covariance in <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Activity across Teleconnected Basins</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tolwinski-Ward, S. E.; Wang, D.</p> <p>2015-12-01</p> <p>Rigorous statistical quantification of natural hazard covariance across regions has important implications for risk management, and is also of fundamental scientific interest. We present a multivariate Bayesian Poisson regression model for inferring the covariance in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) counts across multiple ocean basins and across Saffir-Simpson intensity categories. Such covariability results from the influence of large-scale modes of climate variability on local environments that can alternately suppress or enhance TC genesis and intensification, and our model also simultaneously quantifies the covariance of TC counts with various climatic modes in order to deduce the source of inter-basin TC covariability. The model explicitly treats the time-dependent uncertainty in observed maximum sustained wind data, and hence the nominal intensity category of each TC. Differences in annual TC counts as measured by different agencies are also formally addressed. The probabilistic output of the model can be probed for probabilistic answers to such questions as: - Does the relationship between different categories of TCs differ statistically by basin? - Which climatic predictors have significant relationships with TC activity in each basin? - Are the relationships between counts in different basins conditionally independent given the climatic predictors, or are there other factors at play affecting inter-basin covariability? - How can a portfolio of insured property be optimized across space to minimize risk? Although we present results of our model applied to TCs, the framework is generalizable to covariance estimation between multivariate counts of natural hazards across regions and/or across peril types.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20170927_Archive_e001478.png.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20170927_Archive_e001478.png.html"><span>Lightning Flashes and Gravity Waves in <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Mahasen</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-09-28</p> <p><span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Mahasen is moving north through the Indian Ocean along a track that places landfall along the Bangladesh coast on May 16th around 1200Z. On May 13, 2013 the Suomi NPP satellite caught an interesting glimpse of the storm as it moved off the eastern coast of India. The VIIRS Day-Night Band was able to resolve lightning flashes towards the center of the storm, along with mesopheric gravity waves emanating outwards like ripples in a pond. These gravity waves are of particular interest to air traffic controllers so assist in identifying areas of turbulence. Since the moon was in a new phase, the lights and other surface features of India and Sri Lanka are clearly visible, though the clouds of TC Mahasen are not - a tradeoff that occurs as the amount of moonlight cycles throughout the month. Credit: NASA/NOAA NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOS.A51A..02J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOS.A51A..02J"><span>Air-Deployable Profiling Floats for <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Research</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jayne, S. R.; Robbins, P.; Owens, B.; Ekholm, A.; Dufour, J. E.; Sanabia, E.</p> <p>2016-02-01</p> <p>The development of a smaller profiling float that can be launched from Hurricane Hunter aircraft offers the opportunity to monitor the upper-ocean thermal structure over a time span of many months. These Argo-type profiling floats can be deployed in advance of, or during, a <span class="hlt">tropical</span> <span class="hlt">cyclone</span> from any aircraft equipped with an A-sized (AXBT) launch tube, or from the stern ramp of a C-130. The floats have the same dimensions as an AXBT and weigh about 8.5 kg. Upon deployment, the floats parachute to the surface, detach and automatically begin their programmed mission. The recorded temperature data is averaged over 1-meter bins that are reported back via the Iridium satellite phone network, which is then automatically processed and posted to the GTS. The floats are also reprogrammable via the 2-way communication afforded by Iridium. We report on the results of deployments during the 2014 and 2015 hurricane seasons. Unique observations of the ocean response from Hurricane Ignacio are particularly noteworthy and will be presented. Further plans for continued development of floats include measuring salinity (from an inductive conductivity sensor) and observations of the surface wave field (measured by an onboard accelerometer) will also be described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140011563','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140011563"><span>Improving NASA's Multiscale Modeling Framework for <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Climate Study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shen, Bo-Wen; Nelson, Bron; Cheung, Samson; Tao, Wei-Kuo</p> <p>2013-01-01</p> <p>One of the current challenges in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) research is how to improve our understanding of TC interannual variability and the impact of climate change on TCs. Recent advances in global modeling, visualization, and supercomputing technologies at NASA show potential for such studies. In this article, the authors discuss recent scalability improvement to the multiscale modeling framework (MMF) that makes it feasible to perform long-term TC-resolving simulations. The MMF consists of the finite-volume general circulation model (fvGCM), supplemented by a copy of the Goddard cumulus ensemble model (GCE) at each of the fvGCM grid points, giving 13,104 GCE copies. The original fvGCM implementation has a 1D data decomposition; the revised MMF implementation retains the 1D decomposition for most of the code, but uses a 2D decomposition for the massive copies of GCEs. Because the vast majority of computation time in the MMF is spent computing the GCEs, this approach can achieve excellent speedup without incurring the cost of modifying the entire code. Intelligent process mapping allows differing numbers of processes to be assigned to each domain for load balancing. The revised parallel implementation shows highly promising scalability, obtaining a nearly 80-fold speedup by increasing the number of cores from 30 to 3,335.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997MeApp...4..317B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997MeApp...4..317B"><span>The dry intrusion perspective of extra-<span class="hlt">tropical</span> <span class="hlt">cyclone</span> development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Browning, K. A.</p> <p>1997-12-01</p> <p>The dry intrusion is a coherent region of air descending from near tropopause-level. It often has a clear signature in satellite imagery, especially in the water vapour channel, where it is seen as a ‘dark zone’. Parts of dry intrusions are characterised by high potential vorticity and, upon approaching a low-level baroclinic zone, rapid cyclogenesis may be expected to ensue. The leading edges of dry intrusions are defined by cold [theta]w-fronts (moisture fronts). In some places the dry intrusion undercuts rearward-ascending warm air to give an ana-cold front. In other places it overruns the warm air to produce an upper cold [theta]w-front in advance of the surface cold front. Here the dry intrusion is associated with the generation of potential instability and its eventual release as showers or thunderstorms. Identification of dry intrusions provides the forecaster with additional nowcasting evidence that is especially helpful when issuing severe weather warnings. The identification of water vapour dark zones associated with dry intrusions can also form the basis of methods for validating NWP models. Through their relationship to high potential vorticity, they can provide guidance for bogussing NWP models in situations of potentially severe weather. This article provides an introduction to the structure and behaviour of dry intrusions and their relationship to other aspects of extra-<span class="hlt">tropical</span> <span class="hlt">cyclones</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JAMES...6..680V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JAMES...6..680V"><span>Influence of upper ocean stratification interannual variability on <span class="hlt">tropical</span> <span class="hlt">cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vincent, Emmanuel M.; Emanuel, Kerry A.; Lengaigne, Matthieu; Vialard, Jérôme; Madec, Gurvan</p> <p>2014-09-01</p> <p>Climate modes, such as the El Niño Southern Oscillation (ENSO), influence <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> (TCs) interannual activity through their effect on large-scale atmospheric environment. These climate modes also induce interannual variations of subsurface oceanic stratification, which may also influence TCs. Changes in oceanic stratification indeed modulate the amplitude of TCs-induced cooling, and hence the negative feedback of air-sea interactions on the TC intensity. Here we use a dynamical downscaling approach that couples an axisymmetric TC model to a simple ocean model to quantify this interannual oceanic control on TC activity. We perform twin experiments with contrasted oceanic stratifications representative of interannual variability in each TC-prone region. While subsurface oceanic variations do not significantly affect the number of moderate (Category 3 or less) TCs, they do induce a 30% change of Category 5 TC-days globally, and a 70% change for TCs exceeding 85 m s-1. TCs in the western Pacific and the southwestern Indian Ocean are most sensitive to oceanic interannual variability (with a ˜10 m s-1 modulation of the intensity of strongest storms at low latitude), owing to large upper ocean variations in response to ENSO. These results imply that a representation of ocean stratification variability should benefit operational forecasts of intense TCs and the understanding of their climatic variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HESS...17.3815C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HESS...17.3815C"><span>Impacts of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> on hydrochemistry of a subtropical forest</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, C. T.; Hamburg, S. P.; Hwong, J. L.; Lin, N. H.; Hsueh, M. L.; Chen, M. C.; Lin, T. C.</p> <p>2013-10-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> (typhoons/hurricanes) have major impacts on the biogeochemistry of forest ecosystems, but the stochastic nature and the long intervals between storms means that there are limited data on their effects. We characterised the impacts of 14 typhoons over six years on hydrochemistry of a subtropical forest plantation in Taiwan, a region experiencing frequent typhoons. Typhoons contributed 1/3 of the annual rainfall on average, but ranged from 4 to 55%. The stochastic nature of annual typhoon related precipitation poses a challenge with respect to managing the impacts of these extreme events. This challenge is exacerbated by the fact that typhoon-related rainfall is not significantly correlated with wind velocity, the current focus of weather forecasts. Thus, little advance warning is provided for the hydrological impacts of these storms. The typhoons we studied contributed approximately one third of the annual input and output of most nutrients (except nitrogen) during an average 9.5 day yr-1 period, resulting in nutrient input/output rates an order of magnitude greater than during non-typhoon months. Nitrate output balanced input during the non-typhoon period, but during the typhoon period an average of 10 kg ha-1 yr-1 nitrate was lost. Streamwater chemistry exhibited similarly high variability during typhoon and non-typhoon periods and returned to pre-typhoon levels one to three weeks following each typhoon. The streamwater chemistry appears to be very resilient in response to typhoons, resulting in minimal loss of nutrients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HESSD..10.4537C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HESSD..10.4537C"><span>Impacts of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> on hydrochemistry of a subtropical forest</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, C. T.; Hamburg, S. P.; Hwong, J. L.; Lin, N. H.; Hsueh, M. L.; Chen, M. C.; Lin, T. C.</p> <p>2013-04-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> (typhoons/hurricanes) have major impacts on the biogeochemistry of forest ecosystems, but the stochastic nature and the long intervals between storms means that there are limited data on their effects. We characterized the impacts of 14 typhoons over six years on hydrochemistry of a subtropical forest plantation in Taiwan, a region experiencing frequent typhoons. Typhoons contributed 1/3 of annual rainfall on average, but ranged from 4% to 55%. The stochastic nature of annual typhoon related precipitation poses a challenge with respect to managing the impacts of these extreme events. This challenge is exacerbated by the fact that typhoon-related rainfall is not significantly correlated with wind velocity, the current focus of weather forecasts. Thus little advance warning is provided for the hydrological impacts of these storms. The typhoons we studied contributed approximately one third of the annual input and output of most nutrients (except nitrogen) during an average 9.5d yr-1 period, resulting in nutrient input/output rates an order of magnitude greater than during non-typhoon period. Nitrate output balanced input during the non-typhoon period, but during the typhoon period an average of 10 kg ha-1 yr-1 nitrate was lost. Streamwater chemistry exhibited similarly high variability during typhoon and non-typhoon periods and returned to pre-typhoon levels one to three weeks following each typhoon. The streamwater chemistry appears to be very resilient in response to typhoons, resulting in minimal loss of nutrients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A54F..06D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A54F..06D"><span>On the Origin of Large <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Track Errors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davis, C. A.; Wang, W.; Ahijevych, D.; Fang, X.; Kuo, Y. H.</p> <p>2016-12-01</p> <p>It is well known that errors in the so-called "steering flow" of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs) are linked with TC track errors. While the steering flow includes effects of the TC itself on its own motion, large forecast errors are usually the result of errors in the environmental wind through a deep layer of the troposphere. The present study examines the cause of particularly large track errors in operational TC forecasts. Such large errors, especially when repeated for several forecast cycles, can notably degrade the model performance for an entire season for a given basin. Particularly large errors are shown to result in flows with a saddle point (a col) in the environmental wind field. Forecasts produced when this pattern is present are particularly sensitive to small displacements of the TC relative to the saddle point. We use this concept to illustrate how infamously poor global model forecasts occurred in hurricanes Sandy and Joaquin. Using global ensemble forecasts, and sensitivity simulations with regional and global models, we show how poor vortex initialization, errors in initialization of the synoptic-scale flow, and errors in physical parameterizations all contributed to the errors in Joaquin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A33L3374P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A33L3374P"><span>High Resolution Modeling of <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> Using Rare Event Simulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Plotkin, D. A.; Abbot, D. S.; Weare, J.</p> <p>2014-12-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> (TCs) present a challenge to modeling using general circulation models (GCMs) because they involve processes and structures that are too fine for GCMs to resolve. TCs have fine structures - e.g. the eye, eyewall, and rain bands - with length scales on the order of 10 km, while GCMs have typical resolutions on the order of 50-100 km. High resolution GCM runs that are sufficiently long to exhibit multiple TCs can be prohibitively computationally expensive. Thus, while GCMs exhibit TC-like vortices with similar spatial and temporal frequencies to observed TCs, the ability of GCMs to reproduce fine TC structures remains largely untested. In this study, we use recently developed rare event analysis and simulation methods to selectively simulate TCs under GCMs at very high resolution. These rare event simulation methods have been developed mostly in the context of computational chemistry, but are broadly applicable. They allow (either by careful manipulation of the model or by selection of trajectories) direct and detailed interrogation of the event of interest without introducing error and without the need to simulated for long periods of time to see the event. By creating targeted, high resolution GCM simulations with many TCs, we hope to determine whether or not GCMs can capture fine TC structures such as eyewalls and individual rain bands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AnGeo..28..531C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AnGeo..28..531C"><span>Analysis of gravity-waves produced by intense <span class="hlt">tropical</span> <span class="hlt">cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chane Ming, F.; Chen, Z.; Roux, F.</p> <p>2010-02-01</p> <p>Conventional and wavelet methods are combined to characterize gravity-waves (GWs) produced by two intense <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs) in the upper troposphere and lower stratosphere (UT/LS) from GPS winsonde data. Analyses reveal large contribution of GWs induced by TCs to wave energy densities in the UT/LS. An increase in total energy density of about 30% of the climatological energy density in austral summer was estimated in the LS above Tromelin during TC Dina. Four distinct periods in GW activity in relation with TC Faxai stages is observed in the UT. Globally, GWs have periods of 6 h-2.5 days, vertical wavelenghts of 1-3 km and horizontal wavelengths <1000 km in the UT during the evolution of TCs. Horizontal wavelengths are longer in the LS and about 2200 km during TCs. Convective activity over the basin and GW energy density were modulated by mixed equatorial waves of 3-4 days, 6-8 days and 10-13 days confirmed by Hövmöller diagram, Fourier and wavelet analyses of OLR data. Moreover, location of GW sources is below the tropopause height when TCs are intense otherwise varies at lower tropospheric heights depending on the strength of convection. Finally, the maximum surface wind speeds of TCs Dina and Faxai can be linearly estimated with total energy densities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840003591','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840003591"><span>Forecasting <span class="hlt">tropical</span> <span class="hlt">cyclone</span> recurvature with upper tropospheric winds</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gentry, R. C.</p> <p>1983-01-01</p> <p>Data from 17 <span class="hlt">tropical</span> <span class="hlt">cyclones</span> during the 1974 through 1979 hurricane seasons are used to investigate whether the high level winds far to the northwest, north and northeast of the hurricane center can be used to predict hurricane track recurvature. When the man 200-mb winds 1500 to 2000 km northwest and north of the storm center equal or exceed 20 m/s, 80 per cent of the storms recurved before traveling as much as 12 degrees of longitude farther west. The high winds were also used to predict change in direction of forward motion during the next 72 hours. The regression equations developed explain up to 41 per cent of the variance in future direction. In addition to the geostrophic winds used, winds were also obtained by tracking clouds with successive satellite imagery. The u-components of the satellite winds are highly correlated with the geostrophic winds at 200-mb and could probably be used instead of them when available. The v-components are less highly correlated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRD..116.9114Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRD..116.9114Q"><span>Variations in mean annual <span class="hlt">tropical</span> <span class="hlt">cyclone</span> size in the Atlantic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quiring, Steven; Schumacher, Andrea; Labosier, Chris; Zhu, Laiyin</p> <p>2011-05-01</p> <p>Previous research has focused on predicting <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) size in near real time for individual storms. The purpose of this study is to develop models to explain interannual variations in mean Atlantic TC size, as measured by radius of maximum winds (RMAX) and radial extent of 34 knot winds (17 m s-1; R34), and to identify the nature of the relationship between various environmental and storm-related characteristics and TC size. Our analysis demonstrates that mean annual TC size varies systematically among the subbasins in the Atlantic and therefore it is inappropriate to develop a single model for TC size for the entire Atlantic basin. The most important variable for explaining variations in mean annual TC size is the maximum tangential wind (VMAX). VMAX is negatively related to RMAX in all subbasins and positively related to R34 in all subbasins except the Gulf of Mexico, suggesting that years with more intense TCs tend to have smaller (larger) than average RMAX (R34). Other factors, such as the relationships between sea surface temperature, sea level pressure, and Niño 3.4 suggest that environmental factors may play a secondary role in modulating mean annual TC size. Although there are some similarities with the models developed for predicting short-term changes in TC size, our results indicate that it is not appropriate to apply these models to explain variations in TC size at larger spatial scales and longer temporal scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOS.A52A..03C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOS.A52A..03C"><span>Sensitivity of <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Induced Ocean Response to Wind Stress</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, S.; Doyle, J. D.; Veeramony, J.; Rogers, W.; Fan, Y.; Martin, P.; Campbell, T. J.</p> <p>2016-02-01</p> <p>Significant efforts have been made in recent years to improve the track and intensity forecasts of Navy's operational Coupled Ocean/Atmosphere Mesoscale Prediction System for <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> (COAMPS-TC). In this study, we illustrate some key challenges related to TC intensity prediction and air-sea interaction processes using COAMPS-TC coupled with the 3D circulation Navy Coastal Ocean Model (NCOM). We have identified a low intensity bias in COAMPS-TC partially stems from model biases in the momentum flux utilized by NCOM. We will discuss recent advancements in COAMPS to better quantify the prediction of momentum flux across the air-sea interface by coupling with a wave model Simulating Wave NearShore (SWAN). The recent case of hurricane Blanca (2015), a storm that occurred off the Baha California which produced a significant ocean cold wake of 4-6 °C, is used to examine the sensitivity of ocean response to wind stress in the air-ocean and air-ocean-wave coupled COAMPS-TC. The results show both the coupled TC track and intensity are differ substantially relative to the uncoupled COAMPS-TC. When the wind stress magnitude is reduced to just 1/3 of the uncoupled value, there is a significant damping of the ocean internal wave structure and cold wake magnitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.1158F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.1158F"><span>A reassessment of the integrated impact of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> on surface chlorophyll in the western subtropical North Atlantic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Foltz, Gregory R.; Balaguru, Karthik; Leung, L. Ruby</p> <p>2015-02-01</p> <p>The impact of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> on surface chlorophyll concentration is assessed in the western subtropical North Atlantic Ocean during 1998-2011. Previous studies in this area focused on individual <span class="hlt">cyclones</span> and gave mixed results regarding the importance of <span class="hlt">tropical</span> <span class="hlt">cyclone</span>-induced mixing for changes in surface chlorophyll. Using a more integrated and comprehensive approach that includes quantification of <span class="hlt">cyclone</span>-induced changes in mixed layer depth, here it is shown that accumulated <span class="hlt">cyclone</span> energy explains 22% of the interannual variability in seasonally averaged (June-November) chlorophyll concentration in the western subtropical North Atlantic, after removing the influence of the North Atlantic Oscillation (NAO). The variance explained by <span class="hlt">tropical</span> <span class="hlt">cyclones</span> is thus about 70% of that explained by the NAO, which has well-known impacts in this region. It is therefore likely that <span class="hlt">tropical</span> <span class="hlt">cyclones</span> contribute significantly to interannual variations of primary productivity in the western subtropical North Atlantic during the hurricane season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1182875','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1182875"><span>A Reassessment of the Integrated Impact of <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> on Surface Chlorophyll in the Western Subtropical North Atlantic</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Foltz, Gregory R.; Balaguru, Karthik; Leung, Lai-Yung R.</p> <p>2015-02-28</p> <p>The impact of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> on surface chlorophyll concentration is assessed in the western subtropical North Atlantic Ocean during 1998–2011. Previous studies in this area focused on individual <span class="hlt">cyclones</span> and gave mixed results regarding the importance of <span class="hlt">tropical</span> <span class="hlt">cyclone</span>-induced mixing for changes in surface chlorophyll. Using a more integrated and comprehensive approach that includes quantification of <span class="hlt">cyclone</span>-induced changes in mixed layer depth, here it is shown that accumulated <span class="hlt">cyclone</span> energy explains 22% of the interannual variability in seasonally-averaged (June–November) chlorophyll concentration in the western subtropical North Atlantic, after removing the influence of the North Atlantic Oscillation (NAO). The variance explained by <span class="hlt">tropical</span> <span class="hlt">cyclones</span> is thus about 70% of that explained by the NAO, which has well-known impacts in this region. It is therefore likely that <span class="hlt">tropical</span> <span class="hlt">cyclones</span> contribute significantly to interannual variations of primary productivity in the western subtropical North Atlantic during the hurricane season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AtmEn.118...70J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AtmEn.118...70J"><span>Elevated middle and upper troposphere ozone observed downstream of Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jenkins, Gregory S.; Robjhon, Miliaritiana L.; Reyes, Ashford; Valentine, Adriel; Neves, Luis</p> <p>2015-10-01</p> <p>During the peak period of hurricane activity in the summer of 2010, vertical profiles of ozone using ozonesondes were taken downstream of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in the Western and Eastern Atlantic Ocean basin at Barbados and Cape Verde. Measurements are taken for <span class="hlt">tropical</span> <span class="hlt">cyclones</span> Danielle, Earl, Fiona, Gaston, Julia and Igor. The measurements show an increase in ozone mixing ratios with air originating from the <span class="hlt">tropical</span> <span class="hlt">cyclones</span> at 5-10 km altitude. We suggest that observed lightning activity associated <span class="hlt">tropical</span> <span class="hlt">cyclones</span> and the subsequent production of NOX followed by upper level outflow and subsidence ahead of the <span class="hlt">tropical</span> <span class="hlt">cyclones</span> and aged continental outflow from West Africa thunderstorms produced observed increases in ozone mixing ratios. Hurricane Danielle showed the largest changes in ozone mixing ratio with values increasing from 25 ppb to 70 ppb between 22 and 25 August in the middle troposphere, near 450 hPa; warming and drying in the middle and lower troposphere. Measurements of ozone mixing ratios in Cape Verde show higher ozone mixing ratios prior to the passage of <span class="hlt">tropical</span> storm Julia but low ozone mixing ratios and high relative humidity up to 300 hPa when the storm was in close proximity. This is due most likely the vertically transported from the marine boundary layer.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003BAMS...84..635R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003BAMS...84..635R"><span>Trends in <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Impact: A Study in Andhra Pradesh, India.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Raghavan, S.; Rajesh, S.</p> <p>2003-05-01</p> <p>Contrary to the common perception that <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are on the increase, due perhaps to global warming, studies all over the world show that, although there are decadal variations, there is no definite long-term trend in the frequency or intensity of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> over the period of about a century for which data are available. There is, nevertheless, a sharp increase in the socio-economic impact of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in the form of increasing property damage. An analysis of <span class="hlt">cyclones</span> affecting the state of Andhra Pradesh, India, in the last quarter century by normalizing <span class="hlt">cyclone</span> damage for economic and demographic factors shows that here, as elsewhere, the greater vulnerability is attributable mainly to these factors and not to any increase in frequency or intensity of <span class="hlt">cyclones</span>. The decrease of alertness in disaster management that often occurs after a few years' lull in occurrence of <span class="hlt">cyclones</span>, known as the "fading memory syndrome," also contributes to increases in loss of lives and property damage. This distinction between meteorological and socio-economic causes for the increased impact is important to avoid a tendency for political and administrative decision makers to blame natural causes. They have to take these realities into account, not just in developing a vigilant disaster management system, but in land-use planning, development of coastal districts, and insurance measures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4850380','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4850380"><span>Effects of <span class="hlt">cyclone</span>-generated disturbance on a <span class="hlt">tropical</span> reef foraminifera assemblage</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Strotz, Luke C.; Mamo, Briony L.; Dominey-Howes, Dale</p> <p>2016-01-01</p> <p>The sedimentary record, and associated micropalaeontological proxies, is one tool that has been employed to quantify a region’s <span class="hlt">tropical</span> <span class="hlt">cyclone</span> history. Doing so has largely relied on the identification of allochthonous deposits (sediments and microfossils), sourced from deeper water and entrained by <span class="hlt">tropical</span> <span class="hlt">cyclone</span> waves and currents, in a shallow-water or terrestrial setting. In this study, we examine microfossil assemblages before and after a known <span class="hlt">tropical</span> <span class="hlt">cyclone</span> event (<span class="hlt">Cyclone</span> Hamish) with the aim to better resolve the characteristics of this known signal. Our results identify no allochthonous material associated with <span class="hlt">Cyclone</span> Hamish. Instead, using a swathe of statistical tools typical of ecological studies but rarely employed in the geosciences, we identify new, previously unidentified, signal types. These signals include a homogenising effect, with the level of differentiation between sample sites greatly reduced immediately following <span class="hlt">Cyclone</span> Hamish, and discernible shifts in assemblage diversity. In the subsequent years following Hamish, the surface assemblage returns to its pre-<span class="hlt">cyclone</span> form, but results imply that it is unlikely the community ever reaches steady state. PMID:27126520</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24828193','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24828193"><span>The poleward migration of the location of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> maximum intensity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kossin, James P; Emanuel, Kerry A; Vecchi, Gabriel A</p> <p>2014-05-15</p> <p>Temporally inconsistent and potentially unreliable global historical data hinder the detection of trends in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity. This limits our confidence in evaluating proposed linkages between observed trends in <span class="hlt">tropical</span> <span class="hlt">cyclones</span> and in the environment. Here we mitigate this difficulty by focusing on a metric that is comparatively insensitive to past data uncertainty, and identify a pronounced poleward migration in the average latitude at which <span class="hlt">tropical</span> <span class="hlt">cyclones</span> have achieved their lifetime-maximum intensity over the past 30 years. The poleward trends are evident in the global historical data in both the Northern and the Southern hemispheres, with rates of 53 and 62 kilometres per decade, respectively, and are statistically significant. When considered together, the trends in each hemisphere depict a global-average migration of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity away from the <span class="hlt">tropics</span> at a rate of about one degree of latitude per decade, which lies within the range of estimates of the observed expansion of the <span class="hlt">tropics</span> over the same period. The global migration remains evident and statistically significant under a formal data homogenization procedure, and is unlikely to be a data artefact. The migration away from the <span class="hlt">tropics</span> is apparently linked to marked changes in the mean meridional structure of environmental vertical wind shear and potential intensity, and can plausibly be linked to <span class="hlt">tropical</span> expansion, which is thought to have anthropogenic contributions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH51C1893H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH51C1893H"><span><span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Vulnerability Mapping Using Geospatial Techniques: Application to a Coastal Upazila in Bangladesh</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoque, M. A. A.; Phinn, S. R.; Roelfsema, C. M.; Childs, I.</p> <p>2015-12-01</p> <p><span class="hlt">Cyclones</span> are one of the most catastrophic natural disasters. Globally, many coastal regions are vulnerable to different categories <span class="hlt">cyclones</span>. In Bangladesh, disasters from <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are annual occurrences in coastal areas. The intensity and extent of damage due to <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are very high. An appropriate mapping approach is essential for producing detail vulnerability assessments to deliver useful information for reducing the impacts of <span class="hlt">cyclones</span> on people, property and environment. The present study developed and tested a vulnerability mapping approach for <span class="hlt">tropical</span> <span class="hlt">cyclone</span> impacts in Sarankhola upazila a 151 km2 local government area located in coastal Bangladesh. The study applied the approach by integrating remote sensing, field data and multi-criteria evaluation at regional scales covering <1000 km2. Seven criteria concerned with <span class="hlt">cyclone</span> impacts were considered for the study: elevation, slope, geomorphology, proximity to coastline, proximity to <span class="hlt">cyclone</span> track, land uses and population density. Thematic raster map layers were prepared for every criterion and weighted using Analytical Hierarchy Process (AHP) with sensitivity analysis. Weighted Linear Combination (WLC) technique was used for overlaying standardized criteria maps with their weights to produce the vulnerability map. Our results indicated that 15% of the study area had very high vulnerability; mostly close to the river and densely populated areas, with 40 % area as high vulnerability on cropped grounds. Around 25% area was classified at moderate vulnerability covering most of the forests. The low and very low vulnerable area accounts the 12% and 8% respectively. This approach provided very promising result and it was verified by field survey. The result provides the strong applicability of this approach to assess the vulnerability of coastal Bangladesh to <span class="hlt">tropical</span> <span class="hlt">cyclones</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT........63L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT........63L"><span>Assimilation of hyperspectral satellite radiance observations within <span class="hlt">tropical</span> <span class="hlt">cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Haidao</p> <p></p> <p>The availability of high resolution temperature and water vapor data is critical for the study of mesoscale scale weather phenomena (e.g., convective initiations, and <span class="hlt">tropical</span> <span class="hlt">cyclones</span>). As hyperspectral infrared sounders, the Atmospheric Infrared Sounder (AIRS) and Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) could provide high resolution atmospheric profiles by measuring radiations in many thousands of different channels. This work focuses on the assessment of the potential values of satellite hyperspectral radiance data on the study of convective initiations (CI) and the assimilation of AIRS radiance observations within <span class="hlt">tropical</span> storms. First, the potential capability of hyperspectral infrared measurements (GIFTS) to provide convective precipitation forecasts has been studied and assessed. Using both the observed and the model-predicted profiles as input to the GIFTS radiative transfer model (RTM), it is shown that the simulated GIFTS radiance could capture the high vertical and temporal variability of the real and modeled atmosphere prior to a convective initiation, as well as the differences between observations and model forecasts. This study suggests the potential for hyperspectral infrared radiance data to make an important contribution to the improvement of the forecast skill of convective precipitation. Second, as the first step toward applying AIRS data to <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) prediction, a set of dropsonde profiles during Hurricane Rita (2005) is used to simulate AIRS radiance data and to assess the ability of AIRS data in capturing the vertical variability within TCs through one-dimensional variational (1D-Var) twin experiments. The AIRS observation errors and background errors are first estimated. Five sets of 1D-Var twin experiments are then performed using different combinations of AIRS channels. Finally, results from these 1D-Var experiments are analyzed. Major findings are: (1) AIRS radiance data contain useful information about</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA093278','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA093278"><span>An Evaluation of the Dvorak Technique for Estimating <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Intensities from Satellite Imagery.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1980-07-01</p> <p>AD-A093 278 NAVAL OCEANOGRAPHY COMMAND CENTER/JOINT TYPHOON WARNI-ETC F/B 4/2 AN EVALUATION OF THE DVORAK TECHNIQUE FOR ESTIMATING <span class="hlt">TROPICAL</span> C--ETCIU...JUL Al0. 0 SHEWCHUK, R C WEIR UNCLASSIFIED NOCC/JTAC-TN-8- Al EmhEph~ LEVEIV An Evaluation of thet DVORAK Technique for Estimating <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span>...the accuracy of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensity estimates as derived from the Dvorak technique . Estimates of current intensity and 24-hour forecast</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990064406&hterms=explosive&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dexplosive','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990064406&hterms=explosive&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dexplosive"><span><span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Paka's Initial Explosive Development (10-12 December, 1997)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rodgers, Edward B.; Halverson, Jeff; Simpson, Joanne; Olson, William; Pierce, Harold</p> <p>1999-01-01</p> <p>Convection associated with an equatorial westerly wind burst was first observed late November during the strong El Nino of 1997 at approximately 2000 km southwest of the Hawaiian Islands. This region of convection lead to the formation of twin <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, one in the southern hemisphere named Pam and the other in the northern hemisphere named Paka. During the first week in December, <span class="hlt">tropical</span> <span class="hlt">cyclone</span> Paka, the system of concern, reached <span class="hlt">tropical</span> storm stage as it moved rapidly westward at relatively low latitudes. During the 10-12 of December, Paka rapidly developed into a typhoon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030025289','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030025289"><span>Assessing Impacts of Global Warming on <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Tracks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wu, Li-Guang; Wang, Bin</p> <p>2003-01-01</p> <p>A new approach is proposed to assess the possible impacts of the global climate change on <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) tracks in the western North Pacific (WNP) basin. The idea is based on the premise that the future change of TC track characteristics is primarily determined by changes in large-scale environmental steering flows. It is demonstrated that the main characteristics of the current climatology of TC tracks can be derived from the climatological mean velocity field of TC motion by using a trajectory model. The climatological mean velocity of TC motion, which is composed of the large-scale steering and beta drift, is determined on each grid of the basin. The mean beta drift is estimated from the best track data, and the mean large-scale steering flow is computed from the NCEP/NCAR reanalysis for the current climate state. The derived mean beta drift agrees well with the results of previous observational and numerical studies in terms of its direction and magnitude. The outputs of experiments A2 and B2 of the Geophysical Fluid Dynamics Laboratory (GFDL) R30 climate model suggest that the subtropical high will be persistently weak over the western part of the WNP or shift eastward during July-September in response to the future climate change. By assuming that the mean beta drift in the future climate state is unchanged, the change in the general circulation by 2059 will decrease the TC activities in the WNP, but favor a northward shift of typical TC tracks. As a result, the storm activities in the South China Sea will decrease by about 12%, while the Japan region will experience an increase of TCs by 12-15%. During the period of 2000-2029, the <span class="hlt">tropical</span> storms that affect the China region will increase by 5-6%, but return to the current level during 2030-2059. It is also suggested that, during the period of 2030-2059 <span class="hlt">tropical</span> storms will more frequently affect Japan and the middle latitude region of China given that the formation locations remain the same as in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004JAtS...61.2493M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JAtS...61.2493M"><span><span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Formation in a Sheared Environment: A Case Study.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Molinari, John; Vollaro, David; Corbosiero, Kristen L.</p> <p>2004-11-01</p> <p>The development of Hurricane Danny (1997) from depression to hurricane was examined using cloud-to-ground lightning data, reconnaissance aircraft data, and satellite imagery. Vertical wind shear between 850 and 200 hPa of 5 11 m s-1 produced persistent downshear convective outbreaks that became progressively more intense and closer to the center during the development. Early in the period the storm intensified steadily in the presence of this downshear convection. During the last and most intense outbreak, a second vortex appeared to develop within the convection. Evidence is presented that the new downshear vortex became the dominant vortex and absorbed the original. Based on these events, it is hypothesized that the presence of moderate vertical wind shear accelerated the early development process.Equivalent potential temperature fields within 500 m of the surface were examined. Only well after the period of vortex interaction did the characteristic mature <span class="hlt">tropical</span> <span class="hlt">cyclone</span> radial profile of equivalent potential temperature appear. This came about by the virtual elimination of both low θe values in the core and high θe values outside the core that had been present at previous hours.The growth of Hurricane Danny is viewed in terms of the wind-induced surface heat exchange (WISHE) theory. During the <span class="hlt">tropical</span> depression and early <span class="hlt">tropical</span> storm (“pre-WISHE”) periods, few if any of the assumptions of WISHE were met: vertical wind shear exceeded 5 m s-1, considerable azimuthal asymmetry was present, transient highly buoyant convection occurred, and low values of θe in the storm core suggested the presence of convective downdrafts. It is proposed that 1) vortex interactions and subsequent axisymmetrization produced a single dominant vortex at the surface, and 2) vertical mixing of moist entropy by strong convection moved the sounding toward moist neutrality. By this reasoning, the disturbance then met the key tenets of the known finite-amplitude WISHE instability</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830006563','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830006563"><span><span class="hlt">Tropical</span> <span class="hlt">cyclone</span> track and genesis forecasting using satellite microwave sounder data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kidder, S. Q.</p> <p>1982-01-01</p> <p>Although many dynamical and statistical prediction schemes are available to forecasters, <span class="hlt">tropical</span> <span class="hlt">cyclone</span> track errors are still large. One primary difficulty is that <span class="hlt">tropical</span> <span class="hlt">cyclones</span> exist over the data-sparse <span class="hlt">tropical</span> oceans. Satellite sounders, however, routinely provide numerous data over these areas. Mean layer temperatures from the Scanning Microwave Spectrometer on board the Nimbus 6 satellite are decomposed using empirical orthogonal functions, and the expansion coefficients are related to deviations from the persistence forecast location, to speed change, to direction change and to intensity change. The significance of the regression equations is tested by a null hypothesis of zero correlation coefficient. It appears that significant information about <span class="hlt">tropical</span> <span class="hlt">cyclone</span> motion exists in the satellite-estimated mean layer temperatures, especially at upper levels. A physical interpretation of the statistical results is offered, and a one-storm-out independent test is used to test the stability of the equations. Finally, some further work is suggested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhDT........65J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhDT........65J"><span>On the response to <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in mesoscale oceanic eddies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jaimes, Benjamin</p> <p></p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> (TCs) often change intensity as they move over mesoscale oceanic features, as a function of the oceanic mixed layer (OML) thermal response (cooling) to the storm's wind stress. For example, observational evidence indicates that TCs in the Gulf of Mexico rapidly weaken over <span class="hlt">cyclonic</span> cold core eddies (CCEs) where the cooling response is enhanced, and they rapidly intensify over anticyclonic warm features such as the Loop Current (LC) and Warm Core Eddies (WCEs) where OML cooling is reduced. Understanding this contrasting thermal response has important implications for oceanic feedback to TCs' intensity in forecasting models. Based on numerical experimentation and data acquired during hurricanes Katrina and Rita, this dissertation delineates the contrasting velocity and thermal response to TCs in mesoscale oceanic eddies. Observational evidence and model results indicate that, during the forced stage, the wind-driven horizontal current divergence under the storm's eye is affected by the underlying geostrophic circulation. Upwelling (downwelling) regimes develop when the wind stress vector is with (against) the geostrophic OML velocity vector. During the relaxation stage, background geostrophic circulations modulate vertical dispersion of OML near-inertial energy. The near-inertial velocity response is subsequently shifted toward more sub-inertial frequencies inside WCEs, where rapid vertical dispersion prevents accumulation of kinetic energy in the OML that reduces vertical shears and layer cooling. By contrast, near-inertial oscillations are vertically trapped in OMLs inside CCEs that increases vertical shears and entrainment. Estimates of downward vertical radiation of near-inertial wave energies were significantly stronger in the LC bulge (12.1x10-2 W m-2) compared to that in CCEs (1.8x10-2 W m-2). The rotational and translation properties of the geostrophic eddies have an important impact on the internal wave wake produced by TCs. More near</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1510886K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1510886K"><span>Detection of merger and splitting of extra-<span class="hlt">tropical</span> <span class="hlt">cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kew, Sarah; Hanley, John</p> <p>2013-04-01</p> <p>Results from the project IMILAST (Intercomparison of mid-latitude storm diagnostics) show that, despite a wide variety in the 15 <span class="hlt">cyclone</span> identification and tracking techniques considered, a reasonable agreement on tracks of intense <span class="hlt">cyclones</span> can be reached, at least in the central intensifying stage of the <span class="hlt">cyclone</span> life cycle. In contrast, diagnostics of <span class="hlt">cyclone</span> genesis and lysis events show reduced agreement amongst the methods with genesis and lysis density maps exhibiting coherence over smaller spatial scales. Recent work by Hanley and Caballero claims that multi-centre <span class="hlt">cyclones</span> occur more frequently as storm intensity increases, with an associated increase in the probability of spurious splittings by single-centre tracking routines. We investigate whether the methodological differences in handling of <span class="hlt">cyclone</span> merger and splitting are responsible for the range in genesis/lysis outcomes exhibited in IMILAST results or whether other factors, such as <span class="hlt">cyclone</span> definition, have more influence over the spread. The study is focussed on a number of selected cases of intense <span class="hlt">cyclones</span> that undergo a clear merger or splitting. Of the methods contributing to the IMILAST project, three explicitly handle <span class="hlt">cyclone</span> merger and splitting. In demonstrating the differences between the techniques, we explore what each approach has to offer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.3287N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.3287N"><span>Characterization of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in the South Indian Ocean by using GNSS observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nogherotto, Rita; Biondi, Riccardo; Leclair de Bellevue, Jimmy; Brenot, Hugues</p> <p>2017-04-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> represent the most important weather system involving La Reunion Island and an accurate prediction of their track and intensity is crucial to reduce the damages caused by their strong precipitation and winds. Atmospheric water vapor is the main driver in the development of the <span class="hlt">cyclones</span> and continuous observations of precipitable water (PW) from GNSS constitute a relevant tool in studying its temporal and spatial distribution. Because of the high temporal resolution of their observations, they allow the resolution of high-frequency (e.g. diurnal) variations and they can be used to study, monitor and predict weather extreme events such as the <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. In this work we apply GNSS technique to measure ZTD and to obtain PW over the Southern Indian Ocean for the entire observational available period (2006-2016). We present the response of PW due to the passage of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. Using Radio Occultation profiles, we retrieve the cloud top altitude to find the relationship with storm intensity and PW variation. In addition we show the monitoring of the water vapor contents in direction of GNSS satellites and preliminary results about the 3D field of water vapor density over Reunion Island using tomography for Bejisa <span class="hlt">cyclone</span>. This <span class="hlt">tropical</span> <span class="hlt">cyclone</span> affected Reunion Island and Mauritius in the late December 2013 and early January 2014 with strong consequences both on the population and on energy supplies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A12F..06S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A12F..06S"><span>The Structure and Dynamics of Coherent Vortices in the Eyewall Boundary Layer of <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stern, D. P.; Bryan, G. H.</p> <p>2014-12-01</p> <p>The boundary layer within the eyewall of intense <span class="hlt">tropical</span> <span class="hlt">cyclones</span> has been shown to be both highly turbulent and to contain coherent small-scale (of order 1 km) vortices. Dropsonde observations have indicated that extreme updrafts of 10-25 m/s can occur in the lowest 2 km, sometimes as low as a few hundred meters above the surface. These updrafts are often collocated with or found very nearby to local extrema in horizontal wind speed, which sometimes exceed 100 m/s. Here, the CM1 model is used to simulate intense <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in an <span class="hlt">idealized</span> framework, with horizontal grid spacing as fine as ~30 meters. At this grid spacing, the scales of the vortices are well resolved. By examining individual features and compositing over many updrafts, we find that there is a consistent structure and relationship between vorticity, vertical velocity, and near-surface windspeeds. We quantitatively show that buoyancy is not responsible for the acceleration of strong boundary layer updrafts. Instead, the updrafts are forced by dynamical pressure gradients associated with strong gradients in the velocity fields. It is currently unknown whether dropsonde observations represent quasi-vertical profiles through the features, or if instead the sondes are horizontally advected through the features. Using simulated dropsonde trajectories, we show that sondes are likely to be horizontally advected through features, and therefore apparent vertical variability in observed kinematic and thermodynamic profiles may actually be primarily in the horizontal. In observations, extreme updrafts are almost exclusively found in Category 4 and 5 hurricanes. We conduct simulations at varying intensity to investigate whether or not similar features exist in weaker storms. Finally, we have developed an objective algorithm that allows us to track individual updrafts/vortices in time, and we use this to investigate the evolution and lifecycle of these features and to gain further insight into their</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JAMES...6..700S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JAMES...6..700S"><span>The NOW regional coupled model: Application to the <span class="hlt">tropical</span> Indian Ocean climate and <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Samson, G.; Masson, S.; Lengaigne, M.; Keerthi, M. G.; Vialard, J.; Pous, S.; Madec, G.; Jourdain, N. C.; Jullien, S.; Menkes, C.; Marchesiello, P.</p> <p>2014-09-01</p> <p>This paper presents the NOW regional coupled ocean-atmosphere model built from the NEMO ocean and WRF atmospheric numerical models. This model is applied to the <span class="hlt">tropical</span> Indian Ocean, with the oceanic and atmospheric components sharing a common ¼° horizontal grid. Long experiments are performed over the 1990-2009 period using the Betts-Miller-Janjic (BMJ) and Kain-Fritsch (KF) cumulus parameterizations. Both simulations produce a realistic distribution of seasonal rainfall and a realistic northward seasonal migration of monsoon rainfall over the Indian subcontinent. At subseasonal time scales, the model reasonably reproduces summer monsoon active and break phases, although with underestimated rainfall and surface wind signals. Its relatively high resolution results in realistic spatial and seasonal distributions of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, but it fails to reproduce the strongest observed <span class="hlt">cyclone</span> categories. At interannual time scales, the model reproduces the observed variability associated with the Indian Ocean Dipole (IOD) and the delayed basin-wide warming/cooling induced by the El Niño Southern Oscillation (ENSO). The timing of IOD occurrence in the model generally matches that of the observed events, confirming the influence of ENSO on the IOD development (through the effect of lateral boundary conditions in our simulations). Although the KF and BMJ simulations share a lot in common, KF strongly overestimates rainfall at all time scales. KF also overestimates the number of simulated <span class="hlt">cyclones</span> by a factor two, while simulating stronger events (up to 55 m s-1) compared to BMJ (up to 40 m s-1). These results could be related to an overly active cumulus parameterization in KF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ClDy...45.3365W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ClDy...45.3365W"><span>Regional climate model projections of rainfall from U.S. landfalling <span class="hlt">tropical</span> <span class="hlt">cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wright, Daniel B.; Knutson, Thomas R.; Smith, James A.</p> <p>2015-12-01</p> <p>The eastern United States is vulnerable to flooding from <span class="hlt">tropical</span> <span class="hlt">cyclone</span> rainfall. Understanding how both the frequency and intensity of this rainfall will change in the future climate is a major challenge. One promising approach is the dynamical downscaling of relatively coarse general circulation model results using higher-resolution regional climate models (RCMs). In this paper, we examine the frequency of landfalling <span class="hlt">tropical</span> <span class="hlt">cyclones</span> and associated rainfall properties over the eastern United States using Zetac, an 18-km resolution RCM designed for modeling Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity. Simulations of 1980-2006 <span class="hlt">tropical</span> <span class="hlt">cyclone</span> frequency and rainfall intensity for the months of August-October are compared against results from previous studies and observation-based datasets. The 1980-2006 control simulations are then compared against results from three future climate scenarios: CMIP3/A1B (late twenty-first century) and CMIP5/RCP4.5 (early and late twenty-first century). In CMIP5 early and late twenty-first century projections, the frequency of occurrence of post-landfall <span class="hlt">tropical</span> <span class="hlt">cyclones</span> shows little net change over much of the eastern U.S. despite a decrease in frequency over the ocean. This reflects a greater landfalling fraction in CMIP5 projections, which is not seen in CMIP3-based projections. Average <span class="hlt">tropical</span> <span class="hlt">cyclone</span> rain rates over land within 500 km of the storm center increase by 8-17 % in the future climate projections relative to control. This is at least as much as expected from the Clausius-Clapeyron relation, which links a warmer atmosphere to greater atmospheric water vapor content. Over land, the percent enhancement of area-averaged rain rates from a given <span class="hlt">tropical</span> <span class="hlt">cyclone</span> in the warmer climate is greater for larger averaging radius (300-500 km) than near the storm, particularly for the CMIP3 projections. Although this study does not focus on attribution, the findings are broadly consistent with historical <span class="hlt">tropical</span> <span class="hlt">cyclone</span> rainfall</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20120002759&hterms=cyclones&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcyclones','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20120002759&hterms=cyclones&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcyclones"><span>Application of the Marsupial Paradigm to <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Formation from Northwestward-Propagating Disturbances</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wang, Zhuo; Dunkerton, Timothy J.; Montgomery, Michael T.</p> <p>2012-01-01</p> <p>A wave-tracking algorithm is developed for northwestward-propagating waves that, on occasion, play a role in <span class="hlt">tropical</span> cyclogenesis over the western oceans. To obtain the Lagrangian flow structure, the frame of reference is translated obliquely at the same propagation speed with the precursor disturbance. Trajectory analysis suggests that streamlines in the obliquely translated frame of reference can be used to approximate flow trajectories. The algorithm was applied to Super Typhoon Nakri (2008), <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Erika (2009), and a few other examples. Diagnoses of meteorological analyses and satellite-derived moisture and precipitation fields show that the marsupial framework for <span class="hlt">tropical</span> cyclogenesis in <span class="hlt">tropical</span> easterly waves is relevant also for northwestward-propagating disturbances as are commonly observed in the <span class="hlt">tropical</span> western Atlantic, the Gulf of Mexico, and the western North Pacific. Finally, it is suggested that analysis of the global model data and satellite observations in the marsupial framework can provide useful guidance on early <span class="hlt">tropical</span> <span class="hlt">cyclone</span> advisories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20120002759&hterms=Cyclones&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DCyclones','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20120002759&hterms=Cyclones&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DCyclones"><span>Application of the Marsupial Paradigm to <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Formation from Northwestward-Propagating Disturbances</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wang, Zhuo; Dunkerton, Timothy J.; Montgomery, Michael T.</p> <p>2012-01-01</p> <p>A wave-tracking algorithm is developed for northwestward-propagating waves that, on occasion, play a role in <span class="hlt">tropical</span> cyclogenesis over the western oceans. To obtain the Lagrangian flow structure, the frame of reference is translated obliquely at the same propagation speed with the precursor disturbance. Trajectory analysis suggests that streamlines in the obliquely translated frame of reference can be used to approximate flow trajectories. The algorithm was applied to Super Typhoon Nakri (2008), <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Erika (2009), and a few other examples. Diagnoses of meteorological analyses and satellite-derived moisture and precipitation fields show that the marsupial framework for <span class="hlt">tropical</span> cyclogenesis in <span class="hlt">tropical</span> easterly waves is relevant also for northwestward-propagating disturbances as are commonly observed in the <span class="hlt">tropical</span> western Atlantic, the Gulf of Mexico, and the western North Pacific. Finally, it is suggested that analysis of the global model data and satellite observations in the marsupial framework can provide useful guidance on early <span class="hlt">tropical</span> <span class="hlt">cyclone</span> advisories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5127585','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5127585"><span>Using Proxy Records to Document Gulf of Mexico <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> from 1820-1915</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rohli, Robert V.; DeLong, Kristine L.; Harley, Grant L.; Trepanier, Jill C.</p> <p>2016-01-01</p> <p>Observations of pre-1950 <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are sparse due to observational limitations; therefore, the hurricane database HURDAT2 (1851–present) maintained by the National Oceanic and Atmospheric Administration may be incomplete. Here we provide additional documentation for HURDAT2 from historical United States Army fort records (1820–1915) and other archived documents for 28 landfalling <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, 20 of which are included in HURDAT2, along the northern Gulf of Mexico coast. One event that occurred in May 1863 is not currently documented in the HURDAT2 database but has been noted in other studies. We identify seven <span class="hlt">tropical</span> <span class="hlt">cyclones</span> that occurred before 1851, three of which are potential <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. We corroborate the pre-HURDAT2 storms with a tree-ring reconstruction of hurricane impacts from the Florida Keys (1707–2009). Using this information, we suggest landfall locations for the July 1822 hurricane just west of Mobile, Alabama and 1831 hurricane near Last Island, Louisiana on 18 August. Furthermore, we model the probable track of the August 1831 hurricane using the weighted average distance grid method that incorporates historical <span class="hlt">tropical</span> <span class="hlt">cyclone</span> tracks to supplement report locations. PMID:27898726</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1910527A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1910527A"><span>Extreme waves from <span class="hlt">tropical</span> <span class="hlt">cyclones</span> and climate change in the Gulf of Mexico</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Appendini, Christian M.; Pedrozo-Acuña, Adrian; Meza-Padilla, Rafael; Torres-Freyermuth, Alec; Cerezo-Mota, Ruth; López-González, José</p> <p>2017-04-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> generate extreme waves that represent a risk to infrastructure and maritime activities. The projection of the <span class="hlt">tropical</span> <span class="hlt">cyclones</span> derived wave climate are challenged by the short historical record of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, their low occurrence, and the poor wind field resolution in General Circulation Models. In this study we use synthetic <span class="hlt">tropical</span> <span class="hlt">cyclones</span> to overcome such limitations and be able to characterize present and future wave climate associated with <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in the Gulf of Mexico. Synthetic events derived from the NCEP/NCAR atmospheric reanalysis and the Coupled Model Intercomparison Project Phase 5 models NOAA/GFDL CM3 and UK Met Office HADGEM2-ES, were used to force a third generation wave model to characterize the present and future wave climate under RCP 4.5 and 8.5 escenarios. An increase in wave activity is projected for the future climate, particularly for the GFDL model that shows less bias in the present climate, although some areas are expected to decrease the wave energy. The practical implications of determining the future wave climate is exemplified by means of the 100-year design wave, where the use of the present climate may result in under/over design of structures, since the lifespan of a structure includes the future wave climate period.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27898726','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27898726"><span>Using Proxy Records to Document Gulf of Mexico <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> from 1820-1915.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pino, Jordan V; Rohli, Robert V; DeLong, Kristine L; Harley, Grant L; Trepanier, Jill C</p> <p>2016-01-01</p> <p>Observations of pre-1950 <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are sparse due to observational limitations; therefore, the hurricane database HURDAT2 (1851-present) maintained by the National Oceanic and Atmospheric Administration may be incomplete. Here we provide additional documentation for HURDAT2 from historical United States Army fort records (1820-1915) and other archived documents for 28 landfalling <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, 20 of which are included in HURDAT2, along the northern Gulf of Mexico coast. One event that occurred in May 1863 is not currently documented in the HURDAT2 database but has been noted in other studies. We identify seven <span class="hlt">tropical</span> <span class="hlt">cyclones</span> that occurred before 1851, three of which are potential <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. We corroborate the pre-HURDAT2 storms with a tree-ring reconstruction of hurricane impacts from the Florida Keys (1707-2009). Using this information, we suggest landfall locations for the July 1822 hurricane just west of Mobile, Alabama and 1831 hurricane near Last Island, Louisiana on 18 August. Furthermore, we model the probable track of the August 1831 hurricane using the weighted average distance grid method that incorporates historical <span class="hlt">tropical</span> <span class="hlt">cyclone</span> tracks to supplement report locations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23836646','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23836646"><span>Downscaling CMIP5 climate models shows increased <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity over the 21st century.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Emanuel, Kerry A</p> <p>2013-07-23</p> <p>A recently developed technique for simulating large [O(10(4))] numbers of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in climate states described by global gridded data is applied to simulations of historical and future climate states simulated by six Coupled Model Intercomparison Project 5 (CMIP5) global climate models. <span class="hlt">Tropical</span> <span class="hlt">cyclones</span> downscaled from the climate of the period 1950-2005 are compared with those of the 21st century in simulations that stipulate that the radiative forcing from greenhouse gases increases by over preindustrial values. In contrast to storms that appear explicitly in most global models, the frequency of downscaled <span class="hlt">tropical</span> <span class="hlt">cyclones</span> increases during the 21st century in most locations. The intensity of such storms, as measured by their maximum wind speeds, also increases, in agreement with previous results. Increases in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity are most prominent in the western North Pacific, but are evident in other regions except for the southwestern Pacific. The increased frequency of events is consistent with increases in a genesis potential index based on monthly mean global model output. These results are compared and contrasted with other inferences concerning the effect of global warming on <span class="hlt">tropical</span> <span class="hlt">cyclones</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PCE....94...56F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PCE....94...56F"><span>On the relationship between atmospheric water vapour transport and extra-<span class="hlt">tropical</span> <span class="hlt">cyclones</span> development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ferreira, Juan A.; Liberato, Margarida L. R.; Ramos, Alexandre M.</p> <p>2016-08-01</p> <p>In this study we seek to investigate the role of atmospheric water vapour on the intensification of extra-<span class="hlt">tropical</span> <span class="hlt">cyclones</span> over the North Atlantic Ocean and more specifically to investigate the linkage between atmospheric rivers' conditions leading to the explosive development of extra-<span class="hlt">tropical</span> <span class="hlt">cyclones</span>. Several WRF-ARW simulations for three recent extra-<span class="hlt">tropical</span> storms that had major negative socio-economic impacts in the Iberian Peninsula and south-western Europe (Klaus, 2009; Gong, 2013 and Stephanie, 2014) are performed in which the water vapour content of the initial and boundary conditions are tuned. Analyses of the vertically integrated vapour transport show the dependence of the storms' development on atmospheric water vapour. In addition, results also show changes in the shape of the jet stream resulting in a reduction of the upper wind divergence, which in turn affects the intensification of the extra-<span class="hlt">tropical</span> <span class="hlt">cyclones</span> studied. This study suggests that atmospheric rivers tend to favour the conditions for explosive extra-<span class="hlt">tropical</span> storms' development in the three case studies, as simulations performed without the existence of atmospheric rivers produce shallow mid-latitude <span class="hlt">cyclones</span>, that is, <span class="hlt">cyclones</span> that are not so intense as those on the reference simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3725040','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3725040"><span>Downscaling CMIP5 climate models shows increased <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity over the 21st century</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Emanuel, Kerry A.</p> <p>2013-01-01</p> <p>A recently developed technique for simulating large [O(104)] numbers of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in climate states described by global gridded data is applied to simulations of historical and future climate states simulated by six Coupled Model Intercomparison Project 5 (CMIP5) global climate models. <span class="hlt">Tropical</span> <span class="hlt">cyclones</span> downscaled from the climate of the period 1950–2005 are compared with those of the 21st century in simulations that stipulate that the radiative forcing from greenhouse gases increases by over preindustrial values. In contrast to storms that appear explicitly in most global models, the frequency of downscaled <span class="hlt">tropical</span> <span class="hlt">cyclones</span> increases during the 21st century in most locations. The intensity of such storms, as measured by their maximum wind speeds, also increases, in agreement with previous results. Increases in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity are most prominent in the western North Pacific, but are evident in other regions except for the southwestern Pacific. The increased frequency of events is consistent with increases in a genesis potential index based on monthly mean global model output. These results are compared and contrasted with other inferences concerning the effect of global warming on <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. PMID:23836646</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSHI43A..06U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSHI43A..06U"><span><span class="hlt">Tropical</span> <span class="hlt">Cyclones</span>, Derelict Traps, and the Future of the Florida Keys Commercial Spiny Lobster Fishery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Uhrin, A. V.</p> <p>2016-02-01</p> <p>Derelict spiny lobster (Panulirus argus) traps may move hundreds of meters during high wind events, resulting in tissue abrasion, breakage, and often complete removal of critical seagrass, sponge, and coral habitat. The legacy of commercial trap debris in the Florida Keys (USA) combined with possible increased inputs of debris resulting from a future rise in storm intensity presents an immediate challenge for fisheries management and the sustainability of this fishery where social and ecological vulnerabilities to disturbance are intrinsically linked. Here, predictions of trap loss in relation to wind speed under three scenarios of future <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensification were evaluated across four levels of fishery effort. Across all <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensity scenarios, Excessive effort produced the greatest number of lost traps, followed in decreasing order by Existing, Expected, and Optimal efforts. Under a Business-as-Usual scenario (BAU) of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity, converting from Existing effort to Optimal effort reduced trap loss by over 60%. The scenarios suggest that were Existing fishery effort to be maintained in the coming decades, <span class="hlt">tropical</span> <span class="hlt">cyclone</span>-related trap loss could exceed 4.6-million depending upon the rate of storm intensification. Existing trap retrieval programs cannot remove trap debris equal to the rate it is currently accumulating. The net increase in derelict traps will only be exacerbated under an uncertain future of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensification. This study also underscores the value of scenarios for exploring these issues, particularly evaluation of fisher responses to change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040000680','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040000680"><span>The Structural Changes of <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> Upon Interaction with Vertical Wind Shear</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ritchie, Elizabeth A.</p> <p>2003-01-01</p> <p>The Fourth Convection and Moisture Experiment (CAMEX-4) provided a unique opportunity to observe the distributions and document the roles of important atmospheric factors that impact the development of the core asymmetries and core structural changes of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> embedded in vertical wind shear. The state-of-the-art instruments flown on the NASA DC-8 and ER-2, in addition to those on the NOAA aircraft, provided a unique set of observations that documented the core structure throughout the depth of the <span class="hlt">tropical</span> <span class="hlt">cyclone</span>. These data have been used to conduct a combined observational and modeling study using a state-of-the-art, high- resolution mesoscale model to examine the role of the environmental vertical wind shear in producing <span class="hlt">tropical</span> <span class="hlt">cyclone</span> core asymmetries, and the effects on the structure and intensity of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>.The scientific objectives of this study were to obtain in situ measurements that would allow documentation of the physical mechanisms that influence the development of the asymmetric convection and its effect on the core structure of the <span class="hlt">tropical</span> <span class="hlt">cyclone</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090015387','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090015387"><span>An Extended Forecast of the Frequencies of North Atlantic Basin <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Activity for 2009</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, Robert M.</p> <p>2009-01-01</p> <p>An extended forecast of the frequencies for the 2009 North Atlantic basin hurricane season is presented. Continued increased activity during the 2009 season with numbers of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, hurricanes, and major hurricanes exceeding long-term averages are indicated. Poisson statistics for the combined high-activity intervals (1950-1965 and 1995-2008) give the central 50% intervals to be 9-14, 5-8, and 2-4, respectively, for the number of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, hurricanes, and major hurricanes, with a 23.4% chance of exceeding 14 <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, a 28% chance of exceeding 8 hurricanes, and a 31.9% chance of exceeding 4 major hurricanes. Based strictly on the statistics of the current high-activity interval (1995-2008), the central 50% intervals for the numbers of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, hurricanes, and major hurricanes are 12-18, 6-10, and 3-5, respectively, with only a 5% chance of exceeding 23, 13, or 7 storms, respectively. Also examined are the first differences in 10-yr moving averages and the effects of global warming and decadal-length oscillations on the frequencies of occurrence for North Atlantic basin <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. In particular, temperature now appears to be the principal driver of increased activity and storm strength during the current high-activity interval, with near-record values possible during the 2009 season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A33L3375P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A33L3375P"><span>Response of Seasonal Atlantic <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Activity to Suppression of African Easterly Waves in a Regional Climate Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patricola, C. M.; Saravanan, R.; Chang, P.</p> <p>2014-12-01</p> <p>Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclones</span> and African easterly waves (AEWs) are strongly linked on the synoptic timescale, with about 85% of observed major Atlantic hurricanes originating from AEWs (e.g., Landsea et al. 1993). However, the influence of variability in AEWs on seasonal Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity is not fully understood; a positive correlation between AEW activity and Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity exists on the interannual timescale during just some periods of the observational record (e.g., Thorncroft and Hodges, 2001; Hopsch et al. 2007). This study investigates the impact of AEWs on seasonal Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity using regional climate model simulations in which AEWs were either prescribed or removed through the lateral boundary condition (LBC). The control simulation (10-member ensemble) was run at 27 km resolution and used 6-hourly LBCs from the NCEP CFS Reanalysis and daily NOAA Optimum Interpolation (OI) V2 sea surface temperature (SST) from the year 2005. In the experiment AEWs were suppressed by filtering 2-10 day variability over <span class="hlt">tropical</span> latitudes from the eastern LBC, located along the west coast of the Sahel. The difference in Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> frequency was insignificant between the simulations in which AEWs were prescribed versus suppressed, indicating that AEWs are not necessary to maintain climatological <span class="hlt">tropical</span> <span class="hlt">cyclone</span> frequency even though <span class="hlt">tropical</span> <span class="hlt">cyclones</span> readily originate from these features. This further implies that seasonal Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> frequency is uninfluenced by variability in AEWs, and that the value of AEW variability as a predictor of Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclones</span> is limited to the weekly timescale. However in response to filtering AEWs, accumulated <span class="hlt">cyclone</span> energy significantly increased by about 15% of the control simulation mean and the spatial pattern of track density shifted in association with changes in steering winds. This suggests the importance of AEWs in impacting <span class="hlt">tropical</span> <span class="hlt">cyclone</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA574472','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA574472"><span>Western North Pacific <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Formation and Structure Change in TCS-08</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2012-09-30</p> <p>the <span class="hlt">tropical</span> western North Pacific, pre-<span class="hlt">tropical</span> <span class="hlt">cyclone</span> disturbances range from low-level waves in the easterlies to large monsoon depressions . An... depressions in the western North Pacific. The high resolution European Center for Medium-range Weather Forecasts (ECMWF) analyses from the Year of...<span class="hlt">Tropical</span> Convection program have been utilized in a study of 43 monsoon depressions during 2009. 3 Satellite imagery, TRMM precipitation products</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1712905L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1712905L"><span>Analysis of CAPE in Intensifying <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> Simulated by CM1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Marguerite; Frisius, Thomas</p> <p>2015-04-01</p> <p>The transition of a <span class="hlt">tropical</span> storm to a full blown hurricane (Typhoon) during intensification can be a source of great debate among many well respected scientists. As a result there is a lack of a comprehensive understanding of intensification. The present study aims to lessen some of the confusion by addressing the role of convective available potential energy (CAPE) in cyclogenesis. Previous work by others fail to include this due to assumptions that allow the intensification to occur under different conditions. A series of sensitivity tests were conducted using an idealised set up in the cloud resolving non-hydrostatic model CM1. A base state provided by a Dunion sounding was used with the vortex being initialised using the Rotunno and Emanuel's scheme and the Morrison double-moment cloud microphysical scheme was adopted. All experiments employed a 2km grid spacing with 600 grid points in the horizontal and 500m grid spacing with 59 grid points in the vertical. Two sets of sensitivity tests were done where the distribution of CAPE was investigated. In the first group the base state temperature was perturbed such that the atmosphere cooled and warmed at 0.5K/km and 1K/km in the vertical direction. In the second group the value for the exchange coefficient for enthalpy was increased and decreased by a factor of 2 and 4 for both cases. Since we are only interested in the rate of intensification most results were taken at the time when the rate of intensification was the highest. In the temperature perturbation experiments warming the atmosphere creates less than <span class="hlt">ideal</span> conditions for cyclogenesis which results in no hurricane developing when the air was warmed by 1K/km and a very weak <span class="hlt">tropical</span> <span class="hlt">cyclone</span> developing when the air was warmed by 0.5K/km. As a result of this there is very little CAPE present in both cases. In contrast, cooling the air provides better conditions for cyclogenesis. The amount of CAPE is much greater when the air was cooled by 0.5K/km but the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080040743','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080040743"><span>Have <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> Been Feeding More Extreme Rainfall?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lau, K.-M.; Zhou, Y. P.; Wu, H.-T.</p> <p>2008-01-01</p> <p>We have conducted a study of the relationship between <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) and extreme rain events using GPCP and TRMM rainfall data, and storm track data for July through November (JASON) in the North Atlantic (NAT) and the western North Pacific (WNP). Extreme rain events are defined in terms of percentile rainrate, and TC-rain by rainfall associated with a named TC. Results show that climatologically, 8% of rain events and 17% of the total rain amount in NAT are accounted by TCs, compared to 9% of rain events and 21% of rain amount in WNP. The fractional contribution of accumulated TC-rain to total rain, Omega, increases nearly linearly as a function of rainrate. Extending the analyses using GPCP pentad data for 1979-2005, and for the post-SSM/I period (1988-2005), we find that while there is no significant trend in the total JASON rainfall over NAT or WNP, there is a positive significant trend in heavy rain over both basins for the 1979-2005 period, but not for the post-SSM/I period. Trend analyses of Omega for both periods indicate that TCs have been feeding increasingly more to rainfall extremes in NAT, where the expansion of the warm pool area can explain slight more than 50% of the change in observed trend in total TC rainfall. In WNP, trend signals for Omega are mixed, and the long-term relationship between TC rain and warm pool areas are strongly influenced by interannual and interdecadal variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100035132&hterms=Cyclones&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DCyclones','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100035132&hterms=Cyclones&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DCyclones"><span>Have <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> been Feeding More Extreme Rainfall?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lau, K.-M.; Zhou, Y. P.; Wu, H.-T.</p> <p>2008-01-01</p> <p>We have conducted a study of the relationship between <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) and extreme rain events using GPCP and TRMM rainfall data ; and storm track data for July through November (JASON) in the North Atlantic (NAT) and the western North Pacific (WNP). Extreme rain events are defined in terms of percentile rainrate, and TC-gain by rainfall associated with a named TC. Results show that climatologically, 8% of rain events and 17% of the total rain amount in NAT are accounted by TCs, compared to 9% of rain events, and 21% of rain amount in WN.P. The fractional contribution of accumulated TC-rain to total rain, Omega, increases nearly linearly as a function of rainrate. Extending the analyses using GPCP pentad data for 1979-2005, and for the post-SSM/I period (1988-2005), we find that while there is no significant trend in the total JASON rainfall over NAT or WNP there is a positive significant trend in heavy rain over both basins for the 1979-2005 period, but not for the post-SSM/I period. Trend analyses of Omega for bout periods indicate that TCs have been feeding increasingly more to rainfall extremes in NAT, where the expansion of the warm pool area can explain slightly more than 50% of the change in observed trend in total TC rainfall. In. WNP, trend signals for Omega are mixed, and the loner term relationship between TC rain and warm pool area is strongly influenced by interannual and interdecadal variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.A23B0784S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.A23B0784S"><span><span class="hlt">Tropical</span> <span class="hlt">Cyclone</span>-Induced Ocean Mixing and Ocean Heat Transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sriver, R. L.; Huber, M.</p> <p>2004-12-01</p> <p>Turbulent mixing driven by <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs) creates cool sea surface temperature (SST) anomalies in their wakes. Restoration to `normal' SST patterns must be driven by anomalous (with respect to climatological values) surface fluxes. The upward turbulent mixing of cool water and the anomalous post-storm heat fluxes into the ocean should drive a substantial amount of poleward ocean heat transport (OHT) and significantly perturb the meridional overturning circulation. Given the sensitivity of TC activity to SSTs, strong feedbacks may exist that alter SST gradients and link TC activity to the mean climate state through OHT. A recent study estimates the magnitude of the TC-induced OHT to be on the order of 1015 Watts, representing the majority of the present-day total annual heat transported by the Earth's oceans (Emanuel, 2001, 2002, 2003). Here we analyze a variety of the latest SST and ocean heat content re-analyses datasets, including ECMWF ERA-40, and calculate SST anomalies for the majority of strong TCs occurring during the last forty years. Using SST anomalies, we attempt to quantify the annually averaged global OHT attributable to TC-induced mixing and compare between datasets and measurements/observations. Surface flux data along storm paths are extracted from ERA-40 data, and radiative energy imbalances within storm wakes are also used to calculate the implied OHT. Results are compared with satellite-based climatologies in the period in which they overlap and differences between reanalysis and satellite-based estimates of TC-induced OHT are described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A51P0322L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A51P0322L"><span>A Physically-based <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Rainfall Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, P.; Lin, N.; Smith, J. A.; Emanuel, K.; Chavas, D. R.</p> <p>2015-12-01</p> <p>Rainfall from <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs) can cause extreme flooding. Predicting and understanding TC rainfall is thus important but has received relatively less attention, compared to the wind and surge. Here we present a simple, physically-based rainfall model, where the rain rate is obtained from estimated vertical velocity and specific humidity in the lower troposphere. The involved rainfall mechanisms include: 1) vertical motion at the top of the boundary layer owing to frictional effects; 2) vertical motion in the middle troposphere resulted from the time evolution of the gradient wind; 3) vertical motion forced by topographic interaction as well as 4) baroclinic effect. The model has been applied to Texas and shown to generate rainfall statistics comparable to observations (Zhu et al, 2013). Here we further evaluate this model on an event basis; case studies include Hurricane Irene (2011) and Isabel (2003). Without any calibration, hourly rainfall estimated from this model compares well with those from full numerical weather prediction model (WRF) as well as rainfall climatology models (R-CLIPPER and PHRaM). This comparison demonstrates the model's ability to capture main TC rainfall mechanisms, and it can be used as an effective tool to study the relative contribution of each rainfall mechanism. Ongoing work includes possibly improving the rainfall model by coupling it with a more accurate boundary layer model. Given its high computational efficiency, this rainfall model can be applied to large numbers of ensemble or synthetic simulations. This study fits into our long-term goal to quantify the risk of inland flooding associated with landfalling TCs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeoRL..40..370N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeoRL..40..370N"><span>Deriving robust return periods for <span class="hlt">tropical</span> <span class="hlt">cyclone</span> inundations from sediments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nott, Jonathan F.; Jagger, Thomas H.</p> <p>2013-01-01</p> <p>Return periods for <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) marine inundations are usually derived from synthetic data sets generated from deterministic models or by extrapolating short historical records. Such approaches contain considerable uncertainties because it is difficult to test their veracity until a sufficiently long period has elapsed. These approaches also often only consider storm surges or storm tides and not the total inundation, which includes waves, set-up and run-up, likely to flood a coastal property. An alternative approach is to examine sedimentary records of actual events that occurred throughout the late Holocene. Sedimentary beach ridges are unique amongst the different types of storm inundation sedimentary records because they record variations in the height of total marine inundations rather than a censoring level as occurs with overwash deposits. The limitation in using beach ridges to derive return periods for inundations has been the lack of a robust statistical model that accurately describes the distribution of these events over the past several millennia. Such a model is presented here using a Generalized Extreme Value distribution and Bayesian analysis of a sand beach ridge plain record of extreme TC-generated marine inundations from northeast Australia. Using this approach, the return period of the marine inundation generated by severe TC Yasi is determined. This return period differs considerably from estimates determined using a probability-based approach, which extrapolates from a short historical record. With global climate changing and the magnitude of marine inundations expected to increase, there is mounting pressure to develop national standards for marine flood loadings on coastal buildings. Deriving accurate return periods of these events will be critical to this endeavor, and this approach will be applicable at numerous localities globally where storm deposited beach ridges occur.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100035132&hterms=feeding&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfeeding','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100035132&hterms=feeding&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfeeding"><span>Have <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> been Feeding More Extreme Rainfall?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lau, K.-M.; Zhou, Y. P.; Wu, H.-T.</p> <p>2008-01-01</p> <p>We have conducted a study of the relationship between <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) and extreme rain events using GPCP and TRMM rainfall data ; and storm track data for July through November (JASON) in the North Atlantic (NAT) and the western North Pacific (WNP). Extreme rain events are defined in terms of percentile rainrate, and TC-gain by rainfall associated with a named TC. Results show that climatologically, 8% of rain events and 17% of the total rain amount in NAT are accounted by TCs, compared to 9% of rain events, and 21% of rain amount in WN.P. The fractional contribution of accumulated TC-rain to total rain, Omega, increases nearly linearly as a function of rainrate. Extending the analyses using GPCP pentad data for 1979-2005, and for the post-SSM/I period (1988-2005), we find that while there is no significant trend in the total JASON rainfall over NAT or WNP there is a positive significant trend in heavy rain over both basins for the 1979-2005 period, but not for the post-SSM/I period. Trend analyses of Omega for bout periods indicate that TCs have been feeding increasingly more to rainfall extremes in NAT, where the expansion of the warm pool area can explain slightly more than 50% of the change in observed trend in total TC rainfall. In. WNP, trend signals for Omega are mixed, and the loner term relationship between TC rain and warm pool area is strongly influenced by interannual and interdecadal variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC21C1101K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC21C1101K"><span>Attribution of Annual Maximum Sea Levels to <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khouakhi, A.; Villarini, G.</p> <p>2015-12-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> (TCs) can cause catastrophic storm surges with major social, economic, and ecological impacts in coastal areas. Understanding the contribution of TCs to extreme sea levels is therefore essential. In this work we examine the contribution of TCs to annual maximum sea levels at the global scale, including potential climate controls and temporal changes. Complete global coverage (1842-2014) of historical 6-hour best track TC records are obtained from the International Best Track Archive for Climate Stewardship (IBTrACS) data set. Hourly tide gauge data are obtained from the Joint Archive for Sea Level Research Quality Data Set. There are 177 tide gauge stations with at least 25 complete years of data between 1970 and 2014 (a complete year is defined as having more than 90% of all the hourly measurements in a year). We associate an annual maximum sea level at a given station with a TC if the center of circulation of the storm passed within a certain distance from the station within a given time window. Spatial and temporal sensitivity analyses are performed with varying time windows (6h, 12h) and buffer zones (200km and 500km) around the tide gauge stations. Results highlight large regional differences, with some locations experiencing almost ¾ of their annual maxima during the passage of a TC. The attribution of annual maximum sea level to TCs is particularly high along the coastal areas of the eastern United States, the Gulf of Mexico, China, Japan, Taiwan and Western Australia. Further analyses will examine the role played by El Niño - Southern Oscillation and the potential temporal changes in TC contributions to annual maximum sea levels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A23H0333W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A23H0333W"><span>Extra-<span class="hlt">tropical</span> <span class="hlt">Cyclones</span> and Windstorms in Seasonal Prediction Models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wild, S.; Befort, D. J.; Weisheimer, A.; Knight, J. R.; Thornton, H. E.; Lockwood, J. F.; Hermanson, L.; Leckebusch, G. C.</p> <p>2016-12-01</p> <p>Severe extra-<span class="hlt">tropical</span> <span class="hlt">cyclones</span> (ETC) and associated extreme wind speeds are the predominant cause for severe damages and large insured losses in the majority of European countries. Reliable seasonal forecasts of ETC and windstorms (WS) would thus have great social and economical benefits.In this study we analyse the climatological representation and seasonal prediction skill of ETC and WS in state-of-the-art multi-member seasonal prediction systems, namely ECMWF-System3, ECMWF-System4 and Met Office - HadGEM-GA3 in the core winter months (DJF). ETC identification is based on the Laplacian of the MSLP whilst WS identification is based on near-surface wind speeds.All data sets show good agreement of spatial climatological distributions of ETC and WS in comparison with reanalysis data (ERA-Interim). There are however both positive and negative biases present depending on the model and region analysed. All seasonal prediction systems show widely small to moderate positive skill in forecasting the winter season frequency of ETC and WS over the Northern Hemisphere. The skill is highest for ETC at the downstream end of the Pacific stormtrack and for WS at the downstream end of the Atlantic stormtrack. We thus find significant skill for high impact WS affecting several European regions. Focussing on European WS, we linearly regress the interannual WS frequency onto the North Atlantic Oscillation (NAO) in the reanalysis data and apply this relation to the seasonal forecast models. We find that NAO - predicted WS show also generally positive skill over most parts of Western Europe. Compared to the directly identified and tracked WS the skill is slightly enhanced over parts of the UK and North Sea. We find however lower skill in other Western European regions primarily along the nodal line of the NAO. This suggests that using the NAO as the solely predictor for WS can be beneficial in some regions while forecast skill of seasonal predictions might be lost elsewhere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...48..631Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...48..631Z"><span>Modulation of western North Pacific <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity by the Atlantic Meridional Mode</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Wei; Vecchi, Gabriel A.; Villarini, Gabriele; Murakami, Hiroyuki; Rosati, Anthony; Yang, Xiaosong; Jia, Liwei; Zeng, Fanrong</p> <p>2017-01-01</p> <p>This study examines the year-to-year modulation of the western North Pacific (WNP) <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TC) activity by the Atlantic Meridional Mode (AMM) using both observations and the Geophysical Fluid Dynamics Laboratory Forecast-oriented Low Ocean Resolution Version of CM2.5 (FLOR) global coupled model. 1. The positive (negative) AMM phase suppresses (enhances) WNP TC activity in observations. The anomalous occurrence of WNP TCs results mainly from changes in TC genesis in the southeastern part of the WNP. 2. The observed responses of WNP TC activity to the AMM are connected to the anomalous zonal vertical wind shear (ZVWS) caused by AMM-induced changes to the Walker circulation. During the positive AMM phase, the warming in the North Atlantic induces strong descending flow in the <span class="hlt">tropical</span> eastern and central Pacific, which intensifies the Walker cell in the WNP. The intensified Walker cell is responsible for the suppressed (enhanced) TC genesis in the eastern (western) part of the WNP by strengthening (weakening) ZVWS. 3. The observed WNPTC-AMM linkage is examined by the long-term control and <span class="hlt">idealized</span> perturbations experiment with FLOR-FA. A suite of sensitivity experiments strongly corroborate the observed WNPTC-AMM linkage and underlying physical mechanisms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MAP...tmp....7K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MAP...tmp....7K"><span><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> over the North Indian Ocean: experiments with the high-resolution global icosahedral grid point model GME</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kumkar, Yogesh V.; Sen, P. N.; Chaudhari, Hemankumar S.; Oh, Jai-Ho</p> <p>2017-01-01</p> <p>In this paper, an attempt has been made to conduct a numerical experiment with the high-resolution global model GME to predict the <span class="hlt">tropical</span> storms in the North Indian Ocean during the year 2007. Numerical integrations using the icosahedral hexagonal grid point global model GME were performed to study the evolution of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, viz., Akash, Gonu, Yemyin and Sidr over North Indian Ocean during 2007. It has been seen that the GME model forecast underestimates <span class="hlt">cyclone</span>'s intensity, but the model can capture the evolution of <span class="hlt">cyclone</span>'s intensity especially its weakening during landfall, which is primarily due to the cutoff of the water vapor supply in the boundary layer as <span class="hlt">cyclones</span> approach the coastal region. A series of numerical simulation of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> have been performed with GME to examine model capability in prediction of intensity and track of the <span class="hlt">cyclones</span>. The model performance is evaluated by calculating the root mean square errors as <span class="hlt">cyclone</span> track errors.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ClDy..tmp..495W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ClDy..tmp..495W"><span>A climatological model of North Indian Ocean <span class="hlt">tropical</span> <span class="hlt">cyclone</span> genesis, tracks and landfall</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wahiduzzaman, Mohammad; Oliver, Eric C. J.; Wotherspoon, Simon J.; Holbrook, Neil J.</p> <p>2016-12-01</p> <p>Extensive damage and loss of life can be caused by <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs) that make landfall. Modelling of TC landfall probability is beneficial to insurance/re-insurance companies, decision makers, government policy and planning, and residents in coastal areas. In this study, we develop a climatological model of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> genesis, tracks and landfall for North Indian Ocean (NIO) rim countries based on kernel density estimation, a generalised additive model (GAM) including an Euler integration step, and landfall detection using a country mask approach. Using a 35-year record (1979-2013) of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> track observations from the Joint Typhoon Warning Centre (part of the International Best Track Archive Climate Stewardship Version 6), the GAM is fitted to the observed <span class="hlt">cyclone</span> track velocities as a smooth function of location in each season. The distribution of <span class="hlt">cyclone</span> genesis points is approximated by kernel density estimation. The model simulated TCs are randomly selected from the fitted kernel (TC genesis), and the <span class="hlt">cyclone</span> paths (TC tracks), represented by the GAM together with the application of stochastic innovations at each step, are simulated to generate a suite of NIO rim landfall statistics. Three hindcast validation methods are applied to evaluate the integrity of the model. First, leave-one-out cross validation is applied whereby the country of landfall is determined by the majority vote (considering the location by only highest percentage of landfall) from the simulated tracks. Second, the probability distribution of simulated landfall is evaluated against the observed landfall. Third, the distances between the point of observed landfall and simulated landfall are compared and quantified. Overall, the model shows very good cross-validated hindcast skill of modelled landfalling <span class="hlt">cyclones</span> against observations in each of the NIO <span class="hlt">tropical</span> <span class="hlt">cyclone</span> seasons and for most NIO rim countries, with only a relatively small difference in the percentage of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA554505','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA554505"><span><span class="hlt">Tropical-Cyclone</span> Flow Asymmetries Induced by a Uniform Flow Revisited</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2011-11-01</p> <p>0851077, NOAAs Hurricane Research Division and NASA grants NNH09AK561 and NNG09HG031. References Black PG D’Asoro EA Drennan WM French JR Niller PP...model: Validation tests and simulation of an Atlantic <span class="hlt">cyclone</span> and cold front. Mon. Wea. Rev., 121, 1493-1513. Frank WM Ritchie EA. 1999 Effects of...environmental flow on <span class="hlt">tropical</span> <span class="hlt">cyclone</span> structure. Mon. Wea. Rev., 127, 2044-2061. Frank WM Ritchie EA. 2001 Effects of vertical wind shear on the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA137362','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA137362"><span>An Evaluation of 700 mb Aircraft Reconnaissance Data for Selected Northwest Pacific <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span>.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1983-09-01</p> <p><span class="hlt">cyclones</span> <span class="hlt">Tropical</span> <span class="hlt">cyclone</span> intensity Typhoons Euvln oeta eprtr Hurricanes Eqivat poticentilr epeatr Aircraft reconnaissance Mossticerg ILANNtIACT ?CWM...except far TY Viola . 62 Fi;ure 13. Similar to Fig. 11, except for ST Kim . 62 Figure 14. Similar to Fig. 11, except far ST Irma . . . 63 Figure 15...for super typhoon Irma . .............. 77 Figure 24. Similar to Fig. 20, except for typhoonklice.. . . . . . . .. 78 Figure 25. Similar to Fig. 20</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007GeoRL..3424805K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007GeoRL..3424805K"><span>Statistical ensemble prediction of the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity over the western North Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwon, H. Joe; Lee, Woo-Jeong; Won, Seong-Hee; Cha, Eun-Jeong</p> <p>2007-12-01</p> <p>This paper presents a statistical model to forecast seasonal <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity. In order to give a comprehensive view of seasonal <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity, we include not only the number of total <span class="hlt">tropical</span> <span class="hlt">cyclones</span> but also the number of typhoons and the NTA (Normalized Typhoon Activity) index as the predictands. The model is based on a multiple linear regression model in which the final predictors are selected with respect to minimizing the prediction error rather than simply fitting with past data. The model is expanded into ensemble prediction by considering the uncertainty of the single and deterministic forecast. The probability forecast based on the ensemble model shows reasonably good skill with respect to reliability and relative operating characteristics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009prtu.conf..259L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009prtu.conf..259L"><span>Application of Helical Characteristics of the Velocity Field to Evaluate the Intensity of <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Levina, G.; Glebova, E.; Naumov, A.; Trosnikov, I.</p> <p></p> <p>The paper presents results of numerical analysis for helical features of velocity field to investigate the process of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> formation, namely, the downward helicity flux through the upper boundary of the viscous atmospheric turbulent boundary layer has been calculated. The simulation was carried out by use of the regional atmospheric ETA model and NCEP reanalysis global data. Calculations were performed for two <span class="hlt">tropical</span> <span class="hlt">cyclones</span> - Wilma (Atlantic basin, 2005) and Man-Yi (North-West Pacific, 2007). It has been found, that the chosen helical characteristic reveals an adequate response to basic trends in variation of such important meteorological fields as pressure and wind velocity during the hurricane vortex evolution. The analysis carried out in the paper shows that the helicity flux can be used as an illustrative characteristic to describe the intensity and destructive power of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA552252','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA552252"><span>Modeling the Impacts of Intraseasonal to Interannual Climate Variations on <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Formations in the Western North Pacific</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2011-09-01</p> <p>Johnson 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Postgraduate School Monterey, CA 93943–5000 8. PERFORMING ORGANIZATION REPORT NUMBER...factors (LSEFs) that strongly influence <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) formation: sea surface temperature (SST), low level relative vorticity, vertical wind...from the perspective of several large scale environmental factors (LSEFs) that strongly influence <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) formation: sea surface</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080039554&hterms=Latitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DLatitude','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080039554&hterms=Latitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DLatitude"><span>Interactions Between Vestige Atlantic <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> and Mid-Latitude Storms Over Mediterranean Basin</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, Eric A.; Mehta, Amita; Mugnai, Alberto; Tripoli, Gregory J.</p> <p>2007-01-01</p> <p>One of the more interesting <span class="hlt">tropical</span>-mid-latitude interactions is one that has important effects on precipitation within the Mediterranean basin. This interaction consists of an Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> vestige whose original disturbance travels eastward and northward across Atlantic basin, eventually intermingling with a mid-latitude <span class="hlt">cyclone</span> entering southern Europe and/or the \\bestern Mediterranean Sea. The period for these interactions is from mid-September through November. If the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> and its vestige is able to make the eastward Atlantic transit within the low to mid-levels, or if an upper level potential vorticity perturbation Cjet streak) emitted by a Hurricane in its latter stages within the central Atlantic is able to propagate into and along the longwave pattern affecting the western Mediterranean Sea (MED), then there is the prospect for the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> remnant to produce a major modification of the mid-latitude storm system preparing to affect the MED region. For such an occurrence to take place, it is necessary for an amplifying baroclinic perturbation to be already situated to the rear of a longwave trough, or to be excited by the emitted jet streak to the rear of a longwave trough -- in either case, preparing to affect the western MED. The Algiers City flood of 9-10 November 2001, which killed some 700 people, was produced by a Mediterranean <span class="hlt">cyclone</span> that had been influenced by two vestige Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, 1,orenzo and Noel. A published modeling study involving various of this study's authors has already described the dynamical development of the Algiers storm as it amplified from a developing baroclinic disturbance in the Rossby wave train, into a northern Africa hazardous flood system, then lingered in the western MED as a semi-intense warm core <span class="hlt">cyclone</span>. In our new modeling experiments, we investigate the impact of what might have happened in the eventual precipitation field. had the main features of the <span class="hlt">tropical</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080039554&hterms=alberto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D70%26Ntt%3Dalberto','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080039554&hterms=alberto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D70%26Ntt%3Dalberto"><span>Interactions Between Vestige Atlantic <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> and Mid-Latitude Storms Over Mediterranean Basin</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, Eric A.; Mehta, Amita; Mugnai, Alberto; Tripoli, Gregory J.</p> <p>2007-01-01</p> <p>One of the more interesting <span class="hlt">tropical</span>-mid-latitude interactions is one that has important effects on precipitation within the Mediterranean basin. This interaction consists of an Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> vestige whose original disturbance travels eastward and northward across Atlantic basin, eventually intermingling with a mid-latitude <span class="hlt">cyclone</span> entering southern Europe and/or the \\bestern Mediterranean Sea. The period for these interactions is from mid-September through November. If the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> and its vestige is able to make the eastward Atlantic transit within the low to mid-levels, or if an upper level potential vorticity perturbation Cjet streak) emitted by a Hurricane in its latter stages within the central Atlantic is able to propagate into and along the longwave pattern affecting the western Mediterranean Sea (MED), then there is the prospect for the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> remnant to produce a major modification of the mid-latitude storm system preparing to affect the MED region. For such an occurrence to take place, it is necessary for an amplifying baroclinic perturbation to be already situated to the rear of a longwave trough, or to be excited by the emitted jet streak to the rear of a longwave trough -- in either case, preparing to affect the western MED. The Algiers City flood of 9-10 November 2001, which killed some 700 people, was produced by a Mediterranean <span class="hlt">cyclone</span> that had been influenced by two vestige Atlantic <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, 1,orenzo and Noel. A published modeling study involving various of this study's authors has already described the dynamical development of the Algiers storm as it amplified from a developing baroclinic disturbance in the Rossby wave train, into a northern Africa hazardous flood system, then lingered in the western MED as a semi-intense warm core <span class="hlt">cyclone</span>. In our new modeling experiments, we investigate the impact of what might have happened in the eventual precipitation field. had the main features of the <span class="hlt">tropical</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ClDy...47..623H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ClDy...47..623H"><span>Evidence for the significant role of sea surface temperature distributions over remote <span class="hlt">tropical</span> oceans in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hegde, Anitha Kumari; Kawamura, Ryuichi; Kawano, Tetsuya</p> <p>2016-07-01</p> <p>The role of remote ocean sea surface temperature (SST) in regulating <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) characteristics has been examined by performing numerical experiments with a regional scale model. Model simulations have been carried out to simulate typhoon Man-yi (July 2007), in our case study, under a range of SST conditions over the Indian Ocean and the South China Sea. The intensity and track of the <span class="hlt">cyclone</span> have been systematically changed in sensitivity simulations of cool and warm SSTs over that region, following its peak phase. Warm oceans can substantially reduce the intensification of western North Pacific <span class="hlt">cyclones</span>, whereas cool oceans can enhance their strength. This is intimately associated with the enhancement/weakening of the moisture supply through the moisture conveyor belt (MCB) in the lower troposphere, from the Indian Ocean and South China Sea into the vicinity of the <span class="hlt">cyclone</span> center. When the MCB is interrupted over the South China Sea in warm SST occurrences, the large-scale transport of moisture into the <span class="hlt">cyclone</span> system is significantly reduced, leading to the weakening of the <span class="hlt">cyclone</span> intensity and to the eastward shift of its track. This study shows that changes in remote <span class="hlt">tropical</span> ocean SST can also modulate TCs and thus can help in improving the forecasting of TC intensities and tracks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26385797','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26385797"><span>Impact Factors and Risk Analysis of <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> on a Highway Network.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Saini; Hu, Fuyu; Jaeger, Carlo</p> <p>2016-02-01</p> <p>Coastal areas typically have high social and economic development and are likely to suffer huge losses due to <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. These <span class="hlt">cyclones</span> have a great impact on the transportation network, but there have been a limited number of studies about <span class="hlt">tropical-cyclone</span>-induced transportation network functional damages, especially in Asia. This study develops an innovative measurement and analytical tool for highway network functional damage and risk in the context of a <span class="hlt">tropical</span> <span class="hlt">cyclone</span>, with which we explored the critical spatial characteristics of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> with regard to functional damage to a highway network by developing linear regression models to quantify their relationship. Furthermore, we assessed the network's functional risk and calculated the return periods under different damage levels. In our analyses, we consider the real-world highway network of Hainan province, China. Our results illustrate that the most important spatial characteristics were location (in particular, the midlands), travel distance, landfalling status, and origin coordinates. However, the trajectory direction did not obviously affect the results. Our analyses indicate that the highway network of Hainan province may suffer from a 90% functional damage scenario every 4.28 years. These results have critical policy implications for the transport sector in reference to emergency planning and disaster reduction. © 2015 Society for Risk Analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A21N..04B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A21N..04B"><span>The Tibetan Plateau's Impact on <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> and Implications for the Asian Monsoons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baldwin, J. W.; Bordoni, S.; Vecchi, G. A.</p> <p>2016-12-01</p> <p>Prior climate model simulations have indicated that the Tibetan Plateau and related orography (hereafter TP) play a significant role in enhancing the Indian Monsoon, particularly during its onset, and the East Asian Monsoon. However, these experiments have been performed with climate models unable to resolve key aspects of <span class="hlt">tropical</span> circulation, in particular <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs). Here we explore the influence of the TP on <span class="hlt">tropical</span> circulations in a GFDL GCM at two different atmosphere/land resolutions (50 km and 2 degrees). The higher resolution model, which resolves TCs up to category 3, suggests that the TP has a significant influence on TCs: the TP is found to decrease TC frequency in the Arabian Sea and Bay of Bengal, and increase their frequency across the <span class="hlt">tropical</span> Pacific. Results are compared to the lower resolution, non-TC resolving model to explore dynamical causes of the change, and possible relevance of <span class="hlt">tropical</span> <span class="hlt">cyclone</span>-associated precipitation to the TP's influence on the monsoon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Natur.539..276D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Natur.539..276D"><span>Fluvial sediment supply to a mega-delta reduced by shifting <span class="hlt">tropical-cyclone</span> activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Darby, Stephen E.; Hackney, Christopher R.; Leyland, Julian; Kummu, Matti; Lauri, Hannu; Parsons, Daniel R.; Best, James L.; Nicholas, Andrew P.; Aalto, Rolf</p> <p>2016-11-01</p> <p>The world’s rivers deliver 19 billion tonnes of sediment to the coastal zone annually, with a considerable fraction being sequestered in large deltas, home to over 500 million people. Most (more than 70 per cent) large deltas are under threat from a combination of rising sea levels, ground surface subsidence and anthropogenic sediment trapping, and a sustainable supply of fluvial sediment is therefore critical to prevent deltas being ‘drowned’ by rising relative sea levels. Here we combine suspended sediment load data from the Mekong River with hydrological model simulations to isolate the role of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in transmitting suspended sediment to one of the world’s great deltas. We demonstrate that spatial variations in the Mekong’s suspended sediment load are correlated (r = 0.765, P < 0.1) with observed variations in <span class="hlt">tropical-cyclone</span> climatology, and that a substantial portion (32 per cent) of the suspended sediment load reaching the delta is delivered by runoff generated by rainfall associated with <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. Furthermore, we estimate that the suspended load to the delta has declined by 52.6 ± 10.2 megatonnes over recent years (1981-2005), of which 33.0 ± 7.1 megatonnes is due to a shift in <span class="hlt">tropical-cyclone</span> climatology. Consequently, <span class="hlt">tropical</span> <span class="hlt">cyclones</span> have a key role in controlling the magnitude of, and variability in, transmission of suspended sediment to the coast. It is likely that anthropogenic sediment trapping in upstream reservoirs is a dominant factor in explaining past, and anticipating future, declines in suspended sediment loads reaching the world’s major deltas. However, our study shows that changes in <span class="hlt">tropical-cyclone</span> climatology affect trends in fluvial suspended sediment loads and thus are also key to fully assessing the risk posed to vulnerable coastal systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27760114','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27760114"><span>Fluvial sediment supply to a mega-delta reduced by shifting <span class="hlt">tropical-cyclone</span> activity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Darby, Stephen E; Hackney, Christopher R; Leyland, Julian; Kummu, Matti; Lauri, Hannu; Parsons, Daniel R; Best, James L; Nicholas, Andrew P; Aalto, Rolf</p> <p>2016-11-10</p> <p>The world's rivers deliver 19 billion tonnes of sediment to the coastal zone annually, with a considerable fraction being sequestered in large deltas, home to over 500 million people. Most (more than 70 per cent) large deltas are under threat from a combination of rising sea levels, ground surface subsidence and anthropogenic sediment trapping, and a sustainable supply of fluvial sediment is therefore critical to prevent deltas being 'drowned' by rising relative sea levels. Here we combine suspended sediment load data from the Mekong River with hydrological model simulations to isolate the role of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in transmitting suspended sediment to one of the world's great deltas. We demonstrate that spatial variations in the Mekong's suspended sediment load are correlated (r = 0.765, P < 0.1) with observed variations in <span class="hlt">tropical-cyclone</span> climatology, and that a substantial portion (32 per cent) of the suspended sediment load reaching the delta is delivered by runoff generated by rainfall associated with <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. Furthermore, we estimate that the suspended load to the delta has declined by 52.6 ± 10.2 megatonnes over recent years (1981-2005), of which 33.0 ± 7.1 megatonnes is due to a shift in <span class="hlt">tropical-cyclone</span> climatology. Consequently, <span class="hlt">tropical</span> <span class="hlt">cyclones</span> have a key role in controlling the magnitude of, and variability in, transmission of suspended sediment to the coast. It is likely that anthropogenic sediment trapping in upstream reservoirs is a dominant factor in explaining past, and anticipating future, declines in suspended sediment loads reaching the world's major deltas. However, our study shows that changes in <span class="hlt">tropical-cyclone</span> climatology affect trends in fluvial suspended sediment loads and thus are also key to fully assessing the risk posed to vulnerable coastal systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.......227R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.......227R"><span>Radial-vertical profiles of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> derived from dropsondes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ren, Yifang</p> <p></p> <p>The scopes of this thesis research are two folds: the first one is to the construct the intensity-based composite radial-vertical profiles of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TC) using GPS-based dropsonde observations and the second one is to identify the major deficiencies of Mathur vortices against the dropsonde composites of TCs. The intensity-based dropsonde composites of TCs advances our understanding of the dynamic and thermal structure of TCs of different intensity along the radial direction in and above the boundary layer where lies the devastating high wind that causes property damages and storm surges. The identification of the major deficiencies of Mathur vortices in representing the radial-vertical profiles of TC of different intensity helps to improve numerical predictions of TCs since most operational TC forecast models need to utilize bogus vortices, such as Mathur vortices, to initialize TC forecasts and simulations. We first screen all available GPS dropsonde data within and round 35 named TCs over the <span class="hlt">tropical</span> Atlantic basin from 1996 to 2010 and pair them with TC parameters derived from the best-track data provided by the National Hurricane Center (NHC) and select 1149 dropsondes that have continuous coverage in the lower troposphere. The composite radial-vertical profiles of tangential wind speed, temperature, mixing ratio and humidity are based for each TC category ranging from "<span class="hlt">Tropical</span> Storm" (TS) to "Hurricane Category 1" (H1) through "Hurricane Category 5" (H5). The key findings of the dropsonde composites are: (i) all TCs have the maximum tangential wind within 1 km above the ground and a distance of 1-2 times of the radius of maximum wind (RMW) at the surface; (ii) all TCs have a cold ring surrounding the warm core near the boundary layer at a distance of 1-3 times of the RMW and the cold ring structure gradually diminishes at a higher elevation where the warm core structure prevails along the radial direction; (iii) the existence of such shallow cold</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100031267&hterms=Cyclones&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DCyclones','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100031267&hterms=Cyclones&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DCyclones"><span>Evolution of the <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Integrated Data Exchange And Analysis System (TC-IDEAS)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Turk, J.; Chao, Y.; Haddad, Z.; Hristova-Veleva, S.; Knosp, B.; Lambrigtsen, B.; Li, P.; Licata, S.; Poulsen, W.; Su, H.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20100031267'); toggleEditAbsImage('author_20100031267_show'); toggleEditAbsImage('author_20100031267_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20100031267_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20100031267_hide"></p> <p>2010-01-01</p> <p>The <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Integrated Data Exchange and Analysis System (TC-IDEAS) is being jointly developed by the Jet Propulsion Laboratory (JPL) and the Marshall Space Flight Center (MSFC) as part of NASA's Hurricane Science Research Program. The long-term goal is to create a comprehensive <span class="hlt">tropical</span> <span class="hlt">cyclone</span> database of satellite and airborne observations, in-situ measurements and model simulations containing parameters that pertain to the thermodynamic and microphysical structure of the storms; the air-sea interaction processes; and the large-scale environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100031267&hterms=goodman&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dgoodman','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100031267&hterms=goodman&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dgoodman"><span>Evolution of the <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Integrated Data Exchange And Analysis System (TC-IDEAS)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Turk, J.; Chao, Y.; Haddad, Z.; Hristova-Veleva, S.; Knosp, B.; Lambrigtsen, B.; Li, P.; Licata, S.; Poulsen, W.; Su, H.; Tanelli, S.; Vane, D.; Vu, Q.; Goodman, H. M.; Blakeslee, R.; Conover, H.; Hall, J.; He, Y.; Regner, K.; Knapp, Ken</p> <p>2010-01-01</p> <p>The <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Integrated Data Exchange and Analysis System (TC-IDEAS) is being jointly developed by the Jet Propulsion Laboratory (JPL) and the Marshall Space Flight Center (MSFC) as part of NASA's Hurricane Science Research Program. The long-term goal is to create a comprehensive <span class="hlt">tropical</span> <span class="hlt">cyclone</span> database of satellite and airborne observations, in-situ measurements and model simulations containing parameters that pertain to the thermodynamic and microphysical structure of the storms; the air-sea interaction processes; and the large-scale environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004BAMS...85..845P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004BAMS...85..845P"><span><span class="hlt">TROPICAL</span> <span class="hlt">CYCLONE</span> WINDS AT LANDFALL: The ASOS C-MAN Wind Exposure Documentation Project.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Powell, Mark; Bowman, David; Gilhousen, David; Murillo, Shirley; Carrasco, Nick; St. Fleur, Russell</p> <p>2004-06-01</p> <p>Photographs describing the wind exposure at automatic weather stations susceptible to <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are now available on Web pages at the National Climatic Data Center and the National Data Buoy Center. Given the exposure for one of eight wind direction sectors, a user may estimate the aerodynamic roughness and correct mean wind measurements to an open-terrain exposure. The open-terrain exposure is consistent with the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> advisories and forecasts issued by the National Weather Service, as well as building design wind load standards published by the American Society of Civil Engineers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19597849','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19597849"><span>How do beetle assemblages respond to <span class="hlt">cyclonic</span> disturbance of a fragmented <span class="hlt">tropical</span> rainforest landscape?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Grimbacher, Peter S; Stork, Nigel E</p> <p>2009-09-01</p> <p>There are surprisingly few studies documenting effects of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (including hurricanes and typhoons) on rainforest animals, and especially insects, considering that many <span class="hlt">tropical</span> forests are frequently affected by <span class="hlt">cyclonic</span> disturbance. Consequently, we sampled a beetle assemblage inhabiting 18 upland rainforest sites in a fragmented landscape in north-eastern Queensland, Australia, using a standardised sampling protocol in 2002 and again 12 months after the passage of Severe <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Larry (March 2006). The spatial configuration of sites allowed us to test if the effects of a <span class="hlt">cyclone</span> and those from fragmentation interact. From all insect samples we extracted 12,568 beetles of 382 species from ten families. Beetle species composition was significantly different pre-and post-<span class="hlt">cyclone</span> although the magnitude of faunal change was not large with 205 species, representing 96% of all individuals, present in both sampling events. Sites with the greatest changes to structure had the greatest changes in species composition. At the site level, increases in woody debris and wood-feeding beetle (Scolytinae) counts were significantly correlated but changes in the percent of ground vegetation were not mirrored by changes in the abundance of foliage-feeding beetles (Chrysomelidae). The overall direction of beetle assemblage change was consistent with increasing aridity, presumably caused by the loss of canopy cover. Sites with the greatest canopy loss had the strongest changes in the proportion of species previously identified in the pre-<span class="hlt">cyclone</span> study as preferring arid or moist rainforest environments. The magnitude of fragmentation effects was virtually unaltered by the passage of <span class="hlt">Cyclone</span> Larry. We postulate that in the short-term the effects of <span class="hlt">cyclonic</span> disturbance and forest fragmentation both reduce the extent of moist, interior habitat.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.U53C0066A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.U53C0066A"><span>Disaster, Deprivation and Death: Large but delayed infant mortality in the wake of Filipino <span class="hlt">tropical</span> <span class="hlt">cyclones</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anttila-Hughes, J. K.; Hsiang, S. M.</p> <p>2011-12-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> are some of the most disastrous and damaging of climate events, and estimates of their destructive potential abound in the natural and social sciences. Nonetheless, there have been few systematic estimates of <span class="hlt">cyclones</span>' impact on children's health. This is concerning because <span class="hlt">cyclones</span> leave in their wake a swath of asset losses and economic deprivation, both known to be strong drivers of poor health outcomes among children. In this paper we provide a household-level estimate of the effect of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> on infant mortality in the Philippines, a country with one of the most active <span class="hlt">cyclone</span> climatologies in the world. We reconstruct historical <span class="hlt">cyclones</span> with detailed spatial and temporal resolution, allowing us to estimate the multi-year effects of <span class="hlt">cyclones</span> on individuals living in specific locations. We combine the <span class="hlt">cyclone</span> reconstruction with woman-level fertility and mortality data from four waves of the Filipino Demographic and Health Survey, providing birth histories for over 55,000 women. In multiple regressions that control for year and region fixed effects as well as intra-annual climate variation, we find that there is a pronounced and robust increase in female infant mortality among poor families in the 12-24 months after storms hit. The estimated mortality rate among this demographic subgroup is much larger than official mortality rates reported by the Filipino government immediately after storms, implying that much of a <span class="hlt">cyclone</span>'s human cost arrives well after the storm has passed. We find that high infant mortality rates are associated with declines in poor families' income and expenditures, including consumption of food and medical services, suggesting that the mechanism by which these deaths are effected may be economic deprivation. These results indicate that a major health and welfare impact of storms has been thus far overlooked, but may be easily prevented through appropriately targeted income support policies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.U23E..05H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.U23E..05H"><span>Thermal stress and <span class="hlt">tropical</span> <span class="hlt">cyclones</span> affect economic production in Central America and Caribbean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hsiang, S. M.</p> <p>2009-12-01</p> <p>Surface temperatures and <span class="hlt">tropical</span> <span class="hlt">cyclones</span> have large impacts on economic production. Local <span class="hlt">cyclone</span> energy dissipation reduces output in agriculture and tourism, while stimulating output in construction. High surface temperatures reduce output in several labor-intensive industries; a 1° C increase for two consecutive years results in production losses of ˜13%. The response is greatest during the hottest season and is non-linear, with high temperature days contributing the most to production losses. The structure of this response matches results from a large ergonomics literature, supporting the hypothesis that thermal stress reduces human performance, driving macroeconomic fluctuations. This large response of non-agricultural sectors suggests that current estimates underestimate the scale and scope of economic vulnerabilities to climate change. Responses of each industry to surface temperature, <span class="hlt">tropical</span> <span class="hlt">cyclones</span> and rainfall. Estimates represent the change of value-added in the industry in response to each atmospheric variables during the year of production (L=0) and the years prior (L≥1). The responses to surface temperature are triangles, <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are squares and rainfall are crosses. Estimates are grey if none of the annual responses are significant at the α = 0.1 level. Whiskers indicate 95% confidence intervals. Tourism receipts displays the five years prior (L=1-5) because of the long response of that industry to <span class="hlt">cyclones</span>. Agriculture per worker is also plotted as circles when estimated a second time excluding mainland countries from the sample. Units are: temperature- percent change in output per 0.33°C; <span class="hlt">cyclones</span>- percent changes in output per 1 standard deviation of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> energy; rainfall- percent change in output per 2 cm/month.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1810674C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1810674C"><span><span class="hlt">tropical</span> <span class="hlt">cyclone</span> risk analysis: a decisive role of its track</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chelsea Nam, C.; Park, Doo-Sun R.; Ho, Chang-Hoi</p> <p>2016-04-01</p> <p>The tracks of 85 <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs) that made landfall to South Korea for the period 1979-2010 are classified into four clusters by using a fuzzy c-means clustering method. The four clusters are characterized by 1) east-short, 2) east-long, 3) west-long, and 4) west-short based on the moving routes around Korean peninsula. We conducted risk comparison analysis for these four clusters regarding their hazards, exposure, and damages. Here, hazard parameters are calculated from two different sources independently, one from the best-track data (BT) and the other from the 60 weather stations over the country (WS). The results show distinct characteristics of the four clusters in terms of the hazard parameters and economic losses (EL), suggesting that there is a clear track-dependency in the overall TC risk. It is appeared that whether there occurred an "effective collision" overweighs the intensity of the TC per se. The EL ranking did not agree with the BT parameters (maximum wind speed, central pressure, or storm radius), but matches to WS parameter (especially, daily accumulated rainfall and TC-influenced period). The west-approaching TCs (i.e. west-long and west-short clusters) generally recorded larger EL than the east-approaching TCs (i.e. east-short and east-long clusters), although the east-long clusters are the strongest in BT point of view. This can be explained through the spatial distribution of the WS parameters and the regional EL maps corresponding to it. West-approaching TCs accompanied heavy rainfall on the southern regions with the helps of the topographic effect on their tracks, and of the extended stay on the Korean Peninsula in their extratropical transition, that were not allowed to the east-approaching TCs. On the other hand, some regions had EL that are not directly proportional to the hazards, and this is partly attributed to spatial disparity in wealth and vulnerability. Correlation analysis also revealed the importance of rainfall; daily</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70020198','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70020198"><span>Landfalling <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span>: Forecast Problems and Associated Research Opportunities</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Marks, F.D.; Shay, L.K.; Barnes, G.; Black, P.; Demaria, M.; McCaul, B.; Mounari, J.; Montgomery, M.; Powell, M.; Smith, J.D.; Tuleya, B.; Tripoli, G.; Xie, Lingtian; Zehr, R.</p> <p>1998-01-01</p> <p>The Fifth Prospectus Development Team of the U.S. Weather Research Program was charged to identify and delineate emerging research opportunities relevant to the prediction of local weather, flooding, and coastal ocean currents associated with landfalling U.S. hurricanes specifically, and <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in general. Central to this theme are basic and applied research topics, including rapid intensity change, initialization of and parameterization in dynamical models, coupling of atmospheric and oceanic models, quantitative use of satellite information, and mobile observing strategies to acquire observations to evaluate and validate predictive models. To improve the necessary understanding of physical processes and provide the initial conditions for realistic predictions, a focused, comprehensive mobile observing system in a translating storm-coordinate system is required. Given the development of proven instrumentation and improvement of existing systems, three-dimensional atmospheric and oceanic datasets need to be acquired whenever major hurricanes threaten the United States. The spatial context of these focused three-dimensional datasets over the storm scales is provided by satellites, aircraft, expendable probes released from aircraft, and coastal (both fixed and mobile), moored, and drifting surface platforms. To take full advantage of these new observations, techniques need to be developed to objectively analyze these observations, and initialize models aimed at improving prediction of hurricane track and intensity from global-scale to mesoscale dynamical models. Multinested models allow prediction of all scales from the global, which determine long- term hurricane motion to the convective scale, which affect intensity. Development of an integrated analysis and model forecast system optimizing the use of three-dimensional observations and providing the necessary forecast skill on all relevant spatial scales is required. Detailed diagnostic analyses of these</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT.......155K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT.......155K"><span>Potential indirect effects of aerosol on <span class="hlt">tropical</span> <span class="hlt">cyclone</span> development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krall, Geoffrey</p> <p></p> <p> storm. This study examines the physical mechanisms that could potentially alter a <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) in intensity and dynamics upon ingesting elevated levels of CCN.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28851154','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28851154"><span>Impact of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> track change on regional air quality.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lam, Yun Fat; Cheung, Hung Ming; Ying, Chi Cheong</p> <p>2017-08-25</p> <p>There has been an increase in <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs) in the western North Pacific (WNP) that traverse with a northward recurving track towards East Asia and a decrease in TC tracks entering the South China Sea (SCS) in the past few decades. To investigate the potential impact of the prevailing TC track change on Hong Kong air quality, an analysis has been carried out based on historical data (1991 to 2010) of TC tracks and air quality. Compared to TCs in other regions, TCs in the vicinity of Taiwan (Region 2, R2) have the greatest impact on Hong Kong air quality due to regional transport of air pollutants from the highly industrialized Pearl River Delta (PRD). In the last twenty years, the number of days with TCs in R2 (May to October) has increased by 45% from 111days in the period 1991-2000 to 161days in 2001-2010, during which there was an increase in yearly TC-related pollution episodes of approximately 3 episodes per year in Hong Kong. The enhancement of mean O3 concentration due to TCs in R2 is reported as 82% (~50.8μg/m(3) at a rural station) and 58% (~16.8μg/m(3) at an urban station) higher than the summer averages. A similar enhancement is also observed for PM10 (called RSP) and SO2 with an average of 70% (i.e., 22.2μg/m(3)) and 100% (i.e., 15.2μg/m(3)) increases, respectively. Overall, the 20years of historical data show that the O3 concentrations on the TC-affected days are increasing at the estimated rates of 0.5μg/m(3) and 2.6μg/m(3) per year, respectively, in the urban and remote areas, which are significantly higher than the increase of 0.3μg/m(3) and 0.4μg/m(3) per year in the average summer concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70029351','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70029351"><span><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> and the flood hydrology of Puerto Rico</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Smith, J.A.; Sturdevant-Rees, P.; Baeck, M.L.; Larsen, M.C.</p> <p>2005-01-01</p> <p>Some of the largest unit discharge flood peaks in the stream gaging records of the U.S. Geological Survey (USGS) have occurred in Puerto Rico. Many of these flood peaks are associated with <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. Hurricane Georges, which passed directly over the island on 21-22 September 1998, produced record flood peaks at numerous USGS stations in Puerto Rico. The hydrology and hydrometeorology of extreme flood response in Puerto Rico are examined through analyses of rainfall, based on Weather Surveillance Radar - 1988 Doppler (WSR-88D) radar reflectivity observations and USGS rain gage observations and discharge from USGS stream gaging stations. Peak rainfall accumulations of more than 700 mm occurred in the central mountain region of the island. The largest unit discharge flood peaks, however, were located in the eastern portion of the island in areas with smaller storm total rainfall accumulations but markedly larger rainfall rates at 5-60 min timescale. Orographic precipitation mechanisms played an important role in rainfall distribution over the island of Puerto Rico. Amplification of rainfall accumulations was associated with areas of upslope motion. Elevated low-level cloud water content in regions of upslope motion played an important role in the maximum rainfall accumulations in the central mountain region of Puerto Rico. The largest unit discharge flood peaks, however, were produced by a decaying eye wall mesovortex, which resulted in a 30-45 min period of extreme rainfall rates over the eastern portion of the island. This storm element was responsible for the record flood peak of the Rio Grande de Lo??iza. The role of terrain in development and evolution of the eye wall mesovortex is unclear but is of fundamental importance for assessing extreme flood response from the storm. Hydrologic response is examined through analyses of rainfall and discharge from five pairs of drainage basins, extending from east to west over the island. These analyses point to the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995AtmRe..38..297P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995AtmRe..38..297P"><span>Condensed water in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> "Oliver", 8 February 1993</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pueschel, R. F.; Allen, D. A.; Black, C.; Faisant, S.; Ferry, G. V.; Howard, S. D.; Livingston, J. M.; Redemann, J.; Sorenson, C. E.; Verma, S.</p> <p></p> <p>On February 8, 1993, the NASA DC-8 aircraft profiled from 10,000 to 37,000 feet (3.1-11.3 km) pressure altitude in a stratified section of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> "Oliver" over the Coral Sea northeast of Australia. Size, shape and phase of cloud and precipitation particles were measured with a 2-D Greyscale probe. Cloud/ precipitation particles changed from liquid to ice as soon as the freezing level was reached near 17,000 feet (5.2 km) pressure altitude. The cloud was completely glaciated at -5°C. There was no correlation between ice particle habit and ambient temperature. In the liquid phase, the precipitation-cloud drop concentration was 4.0 × 10 3 m -3, the geometric mean diameter Dg=0.5-0.7 mm, and the liquid water content 0.7-1.9 g m -3. The largest particles anywhere in the cloud, dominated by fused dendrites at concentrations similar to that of raindrops (2.5 × 10 3 m -3) but a higher condensed water content (5.4 g m -3 estimated) were found in the mixed phase; condensed water is removed very effectively from the mixed layer due to high settling velocities of the large mixed particles. The highest number concentration (4.9 × 10 4 m -3), smallest size ( Dg=0.3-0.4 mm), largest surface area (up to 2.6 × 10 2 cm 2 m -3 at 0.4-1.0 g m -3 of condensate) existed in the ice phase at the coldest temperature (-40°C) at 35,000 feet (10.7 km). Each cloud contained aerosol (haze particles) in addition to cloud particles. The aerosol total surface area exceeded that of the cirrus particles at the coldest temperature. Thus, aerosols must play a significant role in the upscattering of solar radiation. Light extinction (6.2 km -1) and backscatter (0.8 sr -1 km -1) was highest in the coldest portion of the cirrus cloud at the highest altitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRD..121.9458J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRD..121.9458J"><span>The effects of moist entropy and moisture budgets on <span class="hlt">tropical</span> <span class="hlt">cyclone</span> development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Juračić, Ana; Raymond, David J.</p> <p>2016-08-01</p> <p>This paper examines the moist entropy and moisture budgets in <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, as well as their relation to <span class="hlt">tropical</span> <span class="hlt">cyclone</span>'s development. This analysis focuses on the dropsonde data collected during Hurricane and Severe Storm Sentinel project and the accompanying satellite data. Two <span class="hlt">tropical</span> <span class="hlt">cyclones</span> of interest are <span class="hlt">Tropical</span> Storm Gabrielle (2013) and Hurricane Edouard (2014). There were three research flights into Gabrielle (2013), during its nondeveloping and decaying stages. Edouard (2014) was visited four times in different stages of its life cycle, twice during the intensification and twice during the decay. Also, we extended our analysis on the larger data set, consisting of 11 nonintensifying and 12 intensifying systems. Our study shows that the moist entropy tends to increase during intensification and decrease during nonintensifying stages. On the other hand, the moisture budget relates better to the <span class="hlt">tropical</span> <span class="hlt">cyclone</span>'s current intensity than its development. The sign of the moist entropy tendency depends on the ability of surface fluxes and irreversible moist entropy generation to overcome lateral export of moist entropy and loss due to radiative cooling. Edouard's decay during the last research flight was likely the result of increasing wind shear and low sea surface temperatures. During its decay, Gabrielle had strong column-integrated lateral export of moist entropy and drying between 1 and 4 km height. This is probably the consequence of a dry environment at multiple levels, amplified by a warm and dry anomaly left behind by previous convective activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004JAtS...61.1209H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JAtS...61.1209H"><span>The Role of “Vortical” Hot Towers in the Formation of <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Diana (1984).</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hendricks, Eric A.; Montgomery, Michael T.; Davis, Christopher A.</p> <p>2004-06-01</p> <p>A high-resolution (3-km horizontal grid spacing) near-cloud-resolving numerical simulation of the formation of Hurricane Diana (1984) is used to examine the contribution of deep convective processes to <span class="hlt">tropical</span> <span class="hlt">cyclone</span> formation. This study is focused on the 3-km horizontal grid spacing simulation because this simulation was previously found to furnish an accurate forecast of the later stages of the observed storm life cycle. The numerical simulation reveals the presence of vortical hot towers, or cores of deep cumulonimbus convection possessing strong vertical vorticity, that arise from buoyancy-induced stretching of local absolute vertical vorticity in a vorticity-rich prehurricane environment.At near-cloud-resolving scales, these vortical hot towers are the preferred mode of convection. They are demonstrated to be the most important influence to the formation of the <span class="hlt">tropical</span> storm via a two-stage evolutionary process: (i) preconditioning of the local environment via diabatic production of multiple small-scale lower-tropospheric <span class="hlt">cyclonic</span> potential vorticity (PV) anomalies, and (ii) multiple mergers and axisymmetrization of these low-level PV anomalies. The local warm-core formation and tangential momentum spinup are shown to be dominated by the organizational process of the diabatically generated PV anomalies; the former process being accomplished by the strong vertical vorticity in the hot tower cores, which effectively traps the latent heat from moist convection. In addition to the organizational process of the PV anomalies, the cyclogenesis is enhanced by the aggregate diabatic heating associated with the vortical hot towers, which produces a net influx of low-level mean angular momentum throughout the genesis.Simpler models are examined to elucidate the underlying dynamics of <span class="hlt">tropical</span> cyclogenesis in this case study. Using the Sawyer Eliassen balanced vortex model to diagnose the macroscale evolution, the cyclogenesis of Diana is demonstrated to proceed in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGC31B1040H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGC31B1040H"><span>Sensitivities of AGCM-Simulated <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> to Varying Initial Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, F.; Posselt, D. J.; Narisetty, N.; Zarzycki, C.; Nair, V.</p> <p>2013-12-01</p> <p>General Circulation Models (GCMs) have been increasingly used to simulate <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> (TCs) and predict their changes due to the effects of climate warming. As such, the motivation is to examine how the development of <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> (TCs) is represented in Atmospheric General circulation Models (AGCMs) and assesses the impact of changes in initial conditions, which include Radius of Maximum wind speed (RMW), Maximum wind speed (MWS), Sea surface temperature (SST), Environmental lapse rate (Gamma) and mid-level relative humidity (500-hPa RH), on modeled TCs. The National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM) has been used to simulate the development of <span class="hlt">idealized</span> TCs over 10 days. A Latin Hypercube Sampling (LHS) method is used to generate two 300-member space-filling ensembles of simulations with grid resolution of 1×1 and 0.5 ×0.5 degree respectively. Composite analysis is first used to analyze the ensemble results, then, the Expanded Multivariate Adaptive Regression Splines (EMARS) method is implemented to characterize various TC response functions. Both 0.5 and 1.0 degree simulations produce a wide range of TC intensities ranging from <span class="hlt">tropical</span> depression to category 4 or 5 on the Saffir-Simpson scale. On average, storms in the higher resolution simulations are stronger than those produced by the coarser-resolution model. Specifically, it is found that (1) the intensity, track, cloud, precipitation and radiative fields of simulated TCs are highly sensitive to changes in the initial vortex characteristics and surrounding environment; (2) nonlinear interaction between the initial conditions is crucial to the distribution of clouds, precipitation, and radiation of simulated TCs; (3) favorable initial conditions are able to produce intense and destructive TCs even in1 ×1 degree resolution global climate models; (4) inter-relationships exist among the cloud radiative forcing, cloud water content, precipitation and intensity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MAP...tmp...41H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MAP...tmp...41H"><span>Looping tracks associated with <span class="hlt">tropical</span> <span class="hlt">cyclones</span> approaching an isolated mountain. Part I: Essential parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Yi-Chih; Lin, Yuh-Lang</p> <p>2017-05-01</p> <p>Essential parameters for making a looping track when a westward-moving <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) approaches a mesoscale mountain are investigated by examining several key nondimensional control parameters with a series of systematic, <span class="hlt">idealized</span> numerical experiments, such as U/Nh, V max/Nh, U/fL x , V max/fR, h/L x , and R/L y . Here U is the uniform zonal wind velocity, N the Brunt-Vaisala frequency, h the mountain height, f the Coriolis parameter, V max the maximum tangential velocity at a radius of R from the <span class="hlt">cyclone</span> center and L x is the halfwidth of the mountain in the east-west direction. It is found that looping tracks (a) tend to occur under small U/Nh and U/fL x , moderate h/L x , and large V max/Nh, which correspond to slow movement (leading to subgeostrophic flow associated with strong orographic blocking), moderate steepness, and strong tangential wind associated with TC vortex; (b) are often accompanied by an area of perturbation high pressure to the northeast of the mountain, which lasts for only a short period; and (c) do not require the existence of a northerly jet. The nondimensional control parameters are consolidated into a TC looping index (LI), {U2 R2 }/{V_{max}2 hLy }} , which is tested by several historical looping and non-looping typhoons approaching Taiwan's Central Mountain Range (CMR) from east or southeast. It is found that LI < 0.0125 may serve as a criterion for looping track to occur.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.A21C0652Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.A21C0652Y"><span><span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Formation in 30-day Simulation Using Cloud-System-Resolving Global Nonhydrostatic Model (NICAM)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yanase, W.; Satoh, M.; Iga, S.; Tomita, H.</p> <p>2007-12-01</p> <p>We are developing an icosahedral-grid non-hydrostatic AGCM, which can explicitly represent cumulus or meso-scale convection over the entire globe. We named the model NICAM (Nonhydrostatic ICosahedral Atmospheric Model). On 2005, we have performed a simulations with horizontal grid intervals of 14, 7 and 3.5 km using realistic topography and sea surface temperature in April 2004 (Miura et al., 2007; GRL). It simulated a typhoon Sudal that actually developed over the Northwestern Pacific in 2004. In the present study, the NICAM model with the horizontal grid interval of 14 km was used for perpetual July experiment with 30 forecasting days. In this simulation, several <span class="hlt">tropical</span> <span class="hlt">cyclones</span> formed over the wesetern and eastern North Pacific, althought the formation over the western North Pacific occured a little further north to the actually observed region. The mature <span class="hlt">tropical</span> <span class="hlt">cyclones</span> with intense wind speed had a structure of a cloud-free eye and eye wall. We have found that the enviromental parameters associated with the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> genesis explain well the simulated region of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> generation. Over the North Atlantic and eastern North Pacific, westward-moving disturbances like African wave are simulated, which seems to be related to the <span class="hlt">cyclone</span> formation over the eastern North Pacific. On the other hand, the simulated <span class="hlt">tropical</span> <span class="hlt">cyclones</span> over the western North Pacifis seem to form by different factors as has been suggested by the previous studies based on observation. Although the model still has some problems and is under continuous improvement, we can discuss what dynamics is to be represented using a global high-resolution model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.U53C0067J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.U53C0067J"><span>Environmental Disaster and Economic Change: Do <span class="hlt">tropical</span> <span class="hlt">cyclones</span> have permanent effects on economic growth and structure?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jina, A.; von der Goltz, J.; Hsiang, S. M.</p> <p>2011-12-01</p> <p>Natural disasters have important, often devastating, effects upon economic growth and well-being. Due to this, disasters have become an active area of recent research and policy attention. However, much of this research has been narrowly focused, relying on anecdotal evidence and aggregated data to support conclusions about disaster impacts in the short-term. Employing a new global data set of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> exposure from 1960 to 2008, we investigate in greater detail whether permanent changes in economic performance and structure can result from these extreme events in some cases. Our macro-economic analyses use the World Development Indicator dataset and have shown promising results: there are dramatic long-term economic transformations associated with <span class="hlt">tropical</span> <span class="hlt">cyclones</span> across a number of countries and industries. This effect is most clearly seen in Small Island Developing States (SIDS) and some countries in Latin America, where negative changes in long-term growth trends are observed in the years following a large <span class="hlt">tropical</span> <span class="hlt">cyclone</span>. In many economies with a high exposure to <span class="hlt">tropical</span> <span class="hlt">cyclone</span> damage, there are noticeable structural changes within the economy. The impacts of disasters might be expressed through various economic and social channels, through direct loss of lives and infrastructure damage; for instance, the destruction of infrastructure such as ports may damage export opportunities where replacement capital is not readily available. These structural changes may have far-reaching implications for economic growth and welfare. Larger nations subjected to the impacts of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are thought to be able to relocate economically important activities that are damaged by <span class="hlt">cyclones</span>, and so long-term trend changes are not observed, even for events that cause a large immediate decrease in national productivity. By investigating in a more rigorous fashion the hypothesis that the environment triggers these permanent economic changes, our work has</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRC..118.6734M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRC..118.6734M"><span>Variability in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> heat potential over the Southwest Indian Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Malan, N.; Reason, C. J. C.; Loveday, B. R.</p> <p>2013-12-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclone</span> heat potential (TCHP) has been proposed as being important for hurricane and typhoon intensity. Here, a climatology of TCHP is developed for the Southwest Indian Ocean, a basin that experiences on average 11-12 <span class="hlt">tropical</span> <span class="hlt">cyclones</span> per year, many of which impact on Mauritius, Reunion and Madagascar, and Mozambique. SODA data and a regional ocean model forced with the GFDL-CORE v.2b reanalysis winds and heat fluxes are used to derive TCHP values during the 1948-2007 period. The results indicate that TCHP increases through the austral summer, peaking in March. Values of TCHP above 40 kJ cm-2, suggested as the minimum needed for <span class="hlt">tropical</span> <span class="hlt">cyclone</span> intensification, are still present in the northern Mozambique Channel in May. A time series of TCHP spatially averaged over the Seychelles-Chagos thermocline ridge (SCTR), an important area for <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, is presented. The model time series, which agrees well with XBT-based observations (r = 0.82, p = 0.01), shows considerable interannual variability overlaying an upward tendency that matches with an observed increase in severe <span class="hlt">tropical</span> <span class="hlt">cyclone</span> days in the Southwest Indian Ocean. Although an increase in severe storms is seen during 1997-2007, the increasing TCHP tendency time series after 1997 coincides with a decrease in total <span class="hlt">cyclone</span> numbers, a mismatch that is ascribed to increased atmospheric anticyclonicity over the basin. Seasons of increased (decreased) TCHP over the SCTR appear to be associated with dry (wet) conditions over certain areas of southern and East Africa and are linked with changes in zonal wind and vertical motion in the midtroposphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.4866M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.4866M"><span>Variability of upper ocean characteristics and <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in the South West Indian Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mawren, Daneeja; Reason, Chris</p> <p>2017-04-01</p> <p>Track and intensity are key aspects of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> behaviour. Intensity may be impacted by the upper ocean heat content integrated over a variable mixing length (known as Tdy) and barrier layer thickness (BLT). Here, the variability of Tdy and BLT in the South West Indian Ocean and their relationships with <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are investigated. It is shown that rapid <span class="hlt">cyclone</span> intensification is influenced by large Tdy values, thick barrier layers and the presence of anticyclonic eddies. For TC generation in the South West Indian Ocean, the parameter Tdy was found to be important. Large BLT overlay with large Tdy values during summer (r = 0.47, November-April) and are modulated by Rossby waves propagation. Tdy and BLT are strongly correlated with ENSO. The 1997-1998 El Niño shows a strong signal in Tdy, SST and BLT over the South West Indian Ocean. Thereafter, an increasing trend in Tdy occurred over most of the basin which may be associated with changes in atmospheric circulation. Increasing SST, Power Dissipation Index and frequency of Category-5 <span class="hlt">tropical</span> <span class="hlt">cyclones</span> also occurred from 1980 to 2010. To further examine the links between <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, Tdy and BLT, an analysis of the ocean response to Category 5 <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Bansi that developed near Madagascar during January 2015 is performed. Its unusual track was found to be linked with the strengthening of the monsoonal north westerlies while its rapid intensification from Category-2 to Category-4 was linked to a high-Tdy region, associated with a warm core eddy and large BLT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5481025','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5481025"><span>Can existing climate models be used to study anthropogenic changes in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> climate</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Broccoli, A.J.; Manabe, S.</p> <p>1990-10-01</p> <p>The utility of current generation climate models for studying the influence of greenhouse warming on the <span class="hlt">tropical</span> storm climatology is examined. A method developed to identify <span class="hlt">tropical</span> <span class="hlt">cyclones</span> is applied to a series of model integrations. The global distribution of <span class="hlt">tropical</span> storms is simulated by these models in a generally realistic manner. While the model resolution is insufficient to reproduce the fine structure of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, the simulated storms become more realistic as resolution is increased. To obtain a preliminary estimate of the response of the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> climatology, CO{sub 2} was doubled using models with varying cloud treatments and different horizontal resolutions. In the experiment with prescribed cloudiness, the number of storm-days, a combined measure of the number and duration of <span class="hlt">tropical</span> storms, undergoes a statistically significant reduction of the number of storm-days is indicated in the experiment with cloud feedback. In both cases the response is independent of horizontal resolution. While the inconclusive nature of these experimental results highlights the uncertainties that remain in examining the details of greenhouse-gas induced climate change, the ability of the models to qualitatively simulate the <span class="hlt">tropical</span> storm climatology suggests that they are appropriate tools for this problem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AdAtS..33..955V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AdAtS..33..955V"><span>Impact of <span class="hlt">cyclone</span> Nilam on <span class="hlt">tropical</span> lower atmospheric dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vinay Kumar, P.; Dutta, Gopa; Ratnam, M. V.; Krishna, E.; Bapiraju, B.; Rao, B. Venkateswara; Mohammad, Salauddin</p> <p>2016-08-01</p> <p>A deep depression formed over the Bay of Bengal on 28 October 2012, and developed into a <span class="hlt">cyclonic</span> storm. After landfall near the south coast of Chennai, <span class="hlt">cyclone</span> Nilam moved north-northwestwards. Coordinated experiments were conducted from the Indian stations of Gadanki (13.5°N, 79.2°E) and Hyderabad (17.4°N, 78.5°E) to study the modification of gravity-wave activity and turbulence by <span class="hlt">cyclone</span> Nilam, using GPS radiosonde and mesosphere-stratosphere-troposphere radar data. The horizontal velocities underwent large changes during the closest approach of the storm to the experimental sites. Hodograph analysis revealed that inertia gravity waves (IGWs) associated with the <span class="hlt">cyclone</span> changed their directions from northeast (control time) to northwest following the path of the <span class="hlt">cyclone</span>. The momentum flux of IGWs and short-period gravity waves (1-8 h) enhanced prior to, and during, the passage of the storm (±0.05 m2 s-2 and ±0.3 m2 s-2, respectively), compared to the flux after its passage. The corresponding body forces underwent similar changes, with values ranging between ±2-4 m s-1 d-1 and ±12-15 m s-1 d-1. The turbulence refractivity structure constant ( C n 2 ) showed large values below 10 km before the passage of the <span class="hlt">cyclone</span> when humidity in the region was very high. Turbulence and humidity reduced during the passage of the storm when a turbulent layer at ~17 km became more intense. Turbulence in the lower troposphere and near the tropopause became weak after the passage of the <span class="hlt">cyclone</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy..tmp..160D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy..tmp..160D"><span>Characteristics and development of European <span class="hlt">cyclones</span> with <span class="hlt">tropical</span> origin in reanalysis data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dekker, Mark M.; Haarsma, Reindert J.; Vries, Hylke de; Baatsen, Michiel; Delden, Aarnout J. van</p> <p>2017-03-01</p> <p>Major storm systems over Europe frequently have a <span class="hlt">tropical</span> origin. This paper analyses the characteristics and dynamics of such <span class="hlt">cyclones</span> in the observational record, using MERRA reanalysis data for the period 1979-2013. By stratifying the <span class="hlt">cyclones</span> along three key phases of their development (<span class="hlt">tropical</span> phase, extratropical transition and final re-intensification), we identify four radically different life cycles: the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> and extratropical <span class="hlt">cyclone</span> life cycles, the classic extratropical transition and the warm seclusion life cycle. More than 50% of the storms reaching Europe from low latitudes follow the warm seclusion life cycle. It also contains the strongest <span class="hlt">cyclones</span>. They are characterized by a warm core and a frontal T-bone structure, with a northwestward warm conveyor belt and the effects of dry intrusion. Rapid deepening occurs in the latest phase, around their arrival in Europe. Both baroclinic instability and release of latent heat contribute to the strong intensification. The pressure minimum occurs often a day after entering Europe, which enhances the potential threat of warm seclusion storms for Europe. The impact of a future warmer climate on the development of these storms is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A33K3348L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A33K3348L"><span>Interactions between <span class="hlt">tropical</span> <span class="hlt">cyclones</span> and mid-latitude systems in the Northeastern Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lugo, A.; Abarca, S. F.; Raga, G. B.; Vargas, D. C.</p> <p>2014-12-01</p> <p>Major challenges in <span class="hlt">tropical</span> meteorology include the short-term forecast of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> (TC) intensity, which is defined as the maximum tangential wind. Several efforts have been made in order to reach this goal over the last decade: Among these efforts, the study of lightning in the TC inner core (the region inside a disc of 100 km radius from the center) as a proxy to deep convection, has the potential to be used as a predictor to forecast intensity (DeMaria et al, 2012, Mon. Wea. Rev., 140, 1828-1842).While most studies focus their objectives in studying the lightning flash density in the inner core, we study the probability of flash occurrence for intensifying and weakening <span class="hlt">cyclones</span>. We have analyzed the trajectories of the observed 62 <span class="hlt">tropical</span> <span class="hlt">cyclones</span> that developed in the basin from 2006 to 2009, and classified them into separate clusters according to their trajectories. These clusters can broadly be described as having trajectories mostly oriented: East-West, towards the central Pacific, NW far from the Mexican coast, parallel to the Mexican coast and recurving towards the Mexican coast.We estimate that probability of inner core lightning occurrence increases as <span class="hlt">cyclones</span> intensify but the probability rapidly decrease as the systems weaken. This is valid for <span class="hlt">cyclones</span> in most of the clusters. However, the <span class="hlt">cyclones</span> that exhibit trajectories that recurve towards the Mexican coast, do not present the same relationship between intensity and inner-core lightning probability, these <span class="hlt">cyclones</span> show little or no decrease in the lightning occurrence probability as they weaken.We hypothesize that one of the reasons for this anomalous behavior is likely the fact that these <span class="hlt">cyclones</span> interact with mid-latitude systems. Mid-latitude systems are important in determining the recurving trajectory but they may also influence the TC by advecting mid-level moisture towards the TC inner core. This additional supply of moisture as the system is approaching land may enhance deep</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23922393','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23922393"><span>Sea surface height evidence for long-term warming effects of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> on the ocean.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mei, Wei; Primeau, François; McWilliams, James C; Pasquero, Claudia</p> <p>2013-09-17</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> have been hypothesized to influence climate by pumping heat into the ocean, but a direct measure of this warming effect is still lacking. We quantified <span class="hlt">cyclone</span>-induced ocean warming by directly monitoring the thermal expansion of water in the wake of <span class="hlt">cyclones</span>, using satellite-based sea surface height data that provide a unique way of tracking the changes in ocean heat content on seasonal and longer timescales. We find that the long-term effect of <span class="hlt">cyclones</span> is to warm the ocean at a rate of 0.32 ± 0.15 PW between 1993 and 2009, i.e., ∼23 times more efficiently per unit area than the background equatorial warming, making <span class="hlt">cyclones</span> potentially important modulators of the climate by affecting heat transport in the ocean-atmosphere system. Furthermore, our analysis reveals that the rate of warming increases with <span class="hlt">cyclone</span> intensity. This, together with a predicted shift in the distribution of <span class="hlt">cyclones</span> toward higher intensities as climate warms, suggests the ocean will get even warmer, possibly leading to a positive feedback.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3780896','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3780896"><span>Sea surface height evidence for long-term warming effects of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> on the ocean</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mei, Wei; Primeau, François; McWilliams, James C.; Pasquero, Claudia</p> <p>2013-01-01</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclones</span> have been hypothesized to influence climate by pumping heat into the ocean, but a direct measure of this warming effect is still lacking. We quantified <span class="hlt">cyclone</span>-induced ocean warming by directly monitoring the thermal expansion of water in the wake of <span class="hlt">cyclones</span>, using satellite-based sea surface height data that provide a unique way of tracking the changes in ocean heat content on seasonal and longer timescales. We find that the long-term effect of <span class="hlt">cyclones</span> is to warm the ocean at a rate of 0.32 ± 0.15 PW between 1993 and 2009, i.e., ∼23 times more efficiently per unit area than the background equatorial warming, making <span class="hlt">cyclones</span> potentially important modulators of the climate by affecting heat transport in the ocean–atmosphere system. Furthermore, our analysis reveals that the rate of warming increases with <span class="hlt">cyclone</span> intensity. This, together with a predicted shift in the distribution of <span class="hlt">cyclones</span> toward higher intensities as climate warms, suggests the ocean will get even warmer, possibly leading to a positive feedback. PMID:23922393</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.1669K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.1669K"><span><span class="hlt">Cyclone</span> induced Upper Ocean Cooling and Modulation of Surface Winds - A study using satellite data over <span class="hlt">tropical</span> ocean region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kvs, Badarinath; Kharol, Shailesh Kumar; Dileep, K. P.</p> <p></p> <p><span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> are associated with intense winds, rain, storm surges and variations in cloud patterns. Accurate forecasting of both track and intensity of a <span class="hlt">tropical</span> <span class="hlt">cyclone</span> requires thorough understanding of meteorological processes. In this study, we evaluate the relationships between sea-surface temperature (SST) and meteorological parameters over Bay of Bengal region, India using microwave satellite remote sensing data. Most of the <span class="hlt">cyclones</span> in this region occur during the pre-monsoon period from April-June and are associated with SST greater than 260 C. We have particularly analyzed the data from two recent <span class="hlt">cyclonic</span> events, Mala that occurred during 24th April 2006 and <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> 01B that occurred during 11th May, 2003. Mala was a very severe <span class="hlt">cyclonic</span> storm equal to category 4 hurricane on the Saffir-Simpson Hurricane Scale. We used two different remote sensing data sets, the <span class="hlt">Tropical</span> Rainfall Measurement Mission Sea Surface Temperature (SST) and the NASA QuikSCAT ocean surface wind vectors to characterize the ocean-atmosphere interactions in cold SST regions formed in the trail of the above two <span class="hlt">cyclone</span> events. Results from the satellite data analysis suggested systematic weakening of wind speed over the cold patch, along the trail of the <span class="hlt">cyclone</span>. A cooling of around 4 to 5 degrees was observed associated with the passage of <span class="hlt">cyclone</span> Mala. Wind speed gradually increased from 2 to 9 m/s from the center to the boundary of the cold patch and showed good correlation with SST (r=0.97). These observations have been validated with another <span class="hlt">cyclone</span> data (<span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> 01B) over the Bay of Bengal region that occurred during May 2003. Our results were consistent with the Wallace hypothesis that SST modulates the surface winds via stability. Mechanisms governing SST and wind speed have been highlighted utilizing data from two different <span class="hlt">tropical</span> <span class="hlt">cyclone</span> events and remote sensing datasets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6832125','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6832125"><span><span class="hlt">Tropical</span> prediction using dynamical nudging, satellite-defined convective heat sources, and a <span class="hlt">cyclone</span> bogus</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Davidson, N.E.; Puri, K. )</p> <p>1992-11-01</p> <p>Some notable problems in <span class="hlt">tropical</span> prediction have been (1) the sensitivity to, and inaccuracies in, the four-dimensional structure of parameterized convective heating, (2) the inability of conventional data networks to adequately define <span class="hlt">tropical</span> <span class="hlt">cyclone</span> structures, and (3) the so-called spinup problem of numerical models. To help overcome some of these deficiencies, a diabatic nudging scheme has been developed for the Bureau of Meteorology Research Center limited-area <span class="hlt">tropical</span> prediction system. A target analysis for the nudging is first obtained from statistical interpolation of all observational data, using, as first-guess field, output from a global assimilation and prediction system. <span class="hlt">Tropical</span> <span class="hlt">cyclones</span> are optionally inserted via bogus wind observations. From 12 or 24 h prior to the base time of the forecast, the prediction model is nudged toward the target analysis. During nudging the 'observationally reliable' rotational wind component is preserved and the heating from the Kuo scheme is replaced by a heating function determined from 6-h satellite-observed cloud-top temperatures. The system introduces realistic <span class="hlt">tropical</span> <span class="hlt">cyclone</span> structures into the initial condition, defines a vertical-motion field consistent with the satellite cloud imagery, enhances rainfall rates during the early hours of the forecast, reduces the occurrence of spurious rainfall maxima, and improves mass-wind balance and retention of <span class="hlt">cyclone</span> circulations during the model integration. Examples of system performance from enhanced observational datasets and from real-time forecasting are presented. Encouraging results for short-term prediction of both <span class="hlt">tropical</span> <span class="hlt">cyclone</span> behavior and rainfall events are documented. 29 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA554608','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA554608"><span>Sensitivity of <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Models to the Surface Drag Coefficient in Different Boundary-Layer Schemes</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2011-10-20</p> <p>Black PG D’Asoro EA Drennan WM French JR Niller PP Sanford TB Terril EJ Walsh EJ Zhang JA 2007 Air- sea exchange in hurricanes. Synthesis of...Atmos. Sci., 66, 3042-3060. Bui HB Smith RK Montgomery MT Peng J. (M4) 2009 Balanced and unbalanced aspects of <span class="hlt">tropical-cyclone</span> intensification. Q. J. R...Theorie der Tropischen Zyklonen. Arch. Meteorol. Geophys. Bioklimatol., A4, 5372. Montgomery MT Smith RK Nguyen SV. 2010 Sensitivity of <span class="hlt">tropical</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992CSR....12..859D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992CSR....12..859D"><span>Effects of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> waves on ecological and geomorphological structures on the Great Barrier Reef</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Done, T. J.</p> <p>1992-07-01</p> <p>Damage to coral reefs caused by <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Ivor (March 1990) on 46 sites over 150 km of the Great Barrier Reef was patchily distributed within 50 km of the path, while at distances 50km from the eye, it was uniformly low. These distances suggest that local wind-generated waves, not ocean swells, may be the major cause of destruction. Wind component incident on each site, UN, was therefore hindcast from <span class="hlt">tropical</span> <span class="hlt">cyclone</span> circulation models. The sum of hourly UN explained about 82% of the variance in an index of total damage and 90% of the destruction of a veneer of dense coral growth up to 1.5 m in thickness. This correlation is consistent with an "attrition" model, in which <span class="hlt">cyclone</span> waves exfoliate reefs, chunk by chunk, over the period of storm waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790017495','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790017495"><span>An atlas of 1976 GEOS-3 radar altimeter data for <span class="hlt">tropical</span> <span class="hlt">cyclone</span> studies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stanley, H. R.; Chan, B.; Givens, C.; Taylor, R.</p> <p>1979-01-01</p> <p>The means for locating and extracting GEOS-3 altimeter data acquired for the analysis of specific hurricanes, typhoons, and other <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are presented. These data are also expected to be extremely useful in the analysis of the behavior of the altimeter instrument in the presence of severe meteorological disturbances as well as provide a data base which can be useful in the resolution of apparently anomalous geoid or sea surface characteristics. Geographic locations of 1976 <span class="hlt">tropical</span> <span class="hlt">cyclones</span> were correlated with the closest approaching orbits of the GEOS-3 satellite and its radar altimeter. The <span class="hlt">cyclone</span> locations and altimeter data were correlated for the 1976 season. The area of coverage includes the northern hemisphere. This document is a sequel to NASA TM-X-69364 which covered the majority of the 1975 season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009GeoRL..36.3817L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009GeoRL..36.3817L"><span>Warm ocean anomaly, air sea fluxes, and the rapid intensification of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> Nargis (2008)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, I.-I.; Chen, Chi-Hong; Pun, Iam-Fei; Liu, W. Timothy; Wu, Chun-Chieh</p> <p>2009-02-01</p> <p>On 2 May 2008, category-4 <span class="hlt">tropical</span> <span class="hlt">cyclone</span> Nargis devastated Myanmar. It was observed that just prior to its landfall, Nargis rapidly intensified from a weak category-1 storm to an intense category-4 storm within only 24 h. Using in situ ocean depth-temperature measurements and satellite altimetry, it is found that Nargis' rapid intensification took place on a pre-existing warm ocean anomaly in the Bay of Bengal. In the anomaly, the subsurface ocean is evidently warmer than climatology, as characterized by the depth of the 26°C isotherm of 73-101 m and the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> heat potential of 77-105 kj cm-2. This pre-existing deep, warm subsurface layer leads to reduction in the <span class="hlt">cyclone</span>-induced ocean cooling, as shown from the ocean mixed layer numerical experiments. As a result, there was a near 300% increase in the air-sea enthalpy flux to support Nargis' rapid intensification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeoRL..40.2400M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeoRL..40.2400M"><span>Analysis of <span class="hlt">tropical</span>-like <span class="hlt">cyclones</span> over the Mediterranean Sea through a combined modeling and satellite approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miglietta, M. M.; Laviola, S.; Malvaldi, A.; Conte, D.; Levizzani, V.; Price, C.</p> <p>2013-05-01</p> <p>Several Mediterranean vortices with characteristics similar to <span class="hlt">tropical</span> <span class="hlt">cyclones</span> are analyzed by means of numerical simulations, satellite products and lightning data. Numerical analysis suggests that the broad <span class="hlt">tropical</span>-like <span class="hlt">cyclone</span> category includes in reality a set of different <span class="hlt">cyclones</span>, ranging from very small and weak vortices to larger and stronger <span class="hlt">cyclones</span>. One case displays a much longer persistence of <span class="hlt">tropical</span> features than the other events. The analysis of the tracks identifies two preferred areas of occurrence: the Ionian sea and the Balearic Islands. The satellite analysis of cloud top height and retrieved rainfall indicates that the stage characterized by the most intense convective activity and rainfall anticipates the mature phase, when the <span class="hlt">cyclone</span> is more intense and characterized by <span class="hlt">tropical</span> features, during which convection is shallower and rainfall weaker. This result is confirmed by a preliminary analysis of the lightning activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960016385','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960016385"><span>An explicit three-dimensional nonhydrostatic numerical simulation of a <span class="hlt">tropical</span> <span class="hlt">cyclone</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tripoli, G. J.</p> <p>1992-01-01</p> <p>A nonhydrostatic numerical simulation of a <span class="hlt">tropical</span> <span class="hlt">cyclone</span> is performed with explicit representation of cumulus on a meso-beta scale grid and for a brief period on a meso-gamma scale grid. Individual cumulus plumes are represented by a combination of explicit resolution and a 1.5 level closure predicting turbulent kinetic energy (TKE).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA497619','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA497619"><span><span class="hlt">Tropical</span> <span class="hlt">Cyclones</span> within the Sedimentary Record: Analyzing Overwash Deposition from Event to Millennial Timescales</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2009-02-01</p> <p>Reconstructing relative flooding intensities responsible for hurricane- Induced deposits from Laguna Playa Grande, Vieques, Puerto Rico…..17 Chapter 4...and Donnelly, 2007; van de Plassche et al., 2004). To date there are relatively few sedimentary reconstructions of <span class="hlt">tropical</span> <span class="hlt">cyclone</span> activity which...consideration when assessing the significance of trends observed within these paleo-storm reconstructions . Given the importance of identifying the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24930493','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24930493"><span>The air-sea interface and surface stress under <span class="hlt">tropical</span> <span class="hlt">cyclones</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Soloviev, Alexander V; Lukas, Roger; Donelan, Mark A; Haus, Brian K; Ginis, Isaac</p> <p>2014-06-16</p> <p><span class="hlt">Tropical</span> <span class="hlt">cyclone</span> track prediction is steadily improving, while storm intensity prediction has seen little progress in the last quarter century. Important physics are not yet well understood and implemented in <span class="hlt">tropical</span> <span class="hlt">cyclone</span> forecast models. Missing and unresolved physics, especially at the air-sea interface, are among the factors limiting storm predictions. In a laboratory experiment and coordinated numerical simulation, conducted in this work, the microstructure of the air-water interface under hurricane force wind resembled Kelvin-Helmholtz shear instability between fluids with a large density difference. Supported by these observations, we bring forth the concept that the resulting two-phase environment suppresses short gravity-capillary waves and alters the aerodynamic properties of the sea surface. The unified wave-form and two-phase parameterization model shows the well-known increase of the drag coefficient (Cd) with wind speed, up to ~30 ms(-1). Around 60 ms(-1), the new parameterization predicts a local peak of Ck/Cd, under constant enthalpy exchange coefficient Ck. This peak may explain rapid intensification of some storms to major <span class="hlt">tropical</span> <span class="hlt">cyclones</span> and the previously reported local peak of lifetime maximum intensity (bimodal distribution) in the best-track records. The bimodal distribution of maximum lifetime intensity, however, can also be explained by environmental parameters of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> alone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRC..122.4392M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRC..122.4392M"><span><span class="hlt">Tropical</span> <span class="hlt">cyclone</span> sensitivity to ocean coupling in the ECMWF coupled model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mogensen, Kristian S.; Magnusson, Linus; Bidlot, Jean-Raymond</p> <p>2017-05-01</p> <p>We present an investigation of the performance of the ECMWF coupled atmosphere-waves-ocean model for different ocean and atmosphere resolutions on a series of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> in the Western Pacific with the aim to better understand the coupled feedback mechanisms in these extreme conditions. For some of the test cases, we only find little impact of coupling the atmosphere to the ocean, while in others, we observe a very large impact. To further understand these differences, we have selected two <span class="hlt">tropical</span> <span class="hlt">cyclones</span> (TCs) as case studies: TC Haiyan (with small impact of coupling) and TC Neoguri (with large impact of coupling). The comparison between these two cases suggests that the upper ocean stratification is the key in determining the strength of the coupled feedback. A strong coupled feedback is found whenever the ocean heat content of the upper layer is low while a very weak coupled feedback is found whenever the ocean has a thick warm mixed layer. The oceanographic response to <span class="hlt">tropical</span> <span class="hlt">cyclones</span> for the two storms has been compared to sea surface temperature and derived surface currents from drifting buoys and to subsurface observations from Argo and ship launched XBT's. These comparisons show that we are able to realistically reproduce the atmospheric and oceanographic interaction during <span class="hlt">tropical</span> <span class="hlt">cyclone</span> conditions which gives us confidence that the coupled modeling system is physically sound.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA556608','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA556608"><span>An Observational Study of <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Spin-Up in Supertyphoon Jangmi and Hurricane Georges</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2011-12-01</p> <p>two theories is that WISHE emphasizes the wind-speed dependent fluxes and the feedback between θe and the swirling wind field near the ocean surface...Definitions Used in this Thesis .............................18 C. <span class="hlt">TROPICAL</span> <span class="hlt">CYCLONE</span> SPIN-UP THEORIES REVIEWED..................19 1. Conventional Spin-Up... Theory ..........................................................19 2. WISHE Spin-Up Theory</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=cyclones&id=EJ1104590','ERIC'); return false;" href="https://eric.ed.gov/?q=cyclones&id=EJ1104590"><span>Preservice Primary Teachers' Depth and Accuracy of Knowledge of <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lane, Rod; Catling, Simon</p> <p>2016-01-01</p> <p>Climatic hazards are a key feature of life. It is vital that teachers are knowledgeable about these phenomena in order to develop their students' understanding of them. This study used a mixed methods approach to examine the accuracy and depth of preservice primary teachers' (n = 430) knowledge of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. The findings suggest that…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Life+AND+keys&id=EJ1104590','ERIC'); return false;" href="http://eric.ed.gov/?q=Life+AND+keys&id=EJ1104590"><span>Preservice Primary Teachers' Depth and Accuracy of Knowledge of <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lane, Rod; Catling, Simon</p> <p>2016-01-01</p> <p>Climatic hazards are a key feature of life. It is vital that teachers are knowledgeable about these phenomena in order to develop their students' understanding of them. This study used a mixed methods approach to examine the accuracy and depth of preservice primary teachers' (n = 430) knowledge of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>. The findings suggest that…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080043594','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080043594"><span>An Estimate of North Atlantic Basin <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Activity for 2008</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, Robert M.</p> <p>2008-01-01</p> <p>The statistics of North Atlantic basin <span class="hlt">tropical</span> <span class="hlt">cyclones</span> for the interval 1945-2007 are examined and estimates are given for the frequencies of occurrence of the number of <span class="hlt">tropical</span> <span class="hlt">cyclones</span>, number of hurricanes, number of major hurricanes, number of category 4/5 hurricanes, and number of U.S. land-falling hurricanes for the 2008 hurricane season. Also examined are the variations of peak wind speed, average peak wind speed per storm, lowest pressure, average lowest pressure per storm, recurrence rate and duration of extreme events (El Nino and La Nina), the variation of 10-yr moving averages of parametric first differences, and the association of decadal averages of frequencies of occurrence of North Atlantic basin <span class="hlt">tropical</span> <span class="hlt">cyclones</span> against decadal averages of Armagh Observatory, Northern Ireland, annual mean temperature (found to be extremely important for number of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> and number of hurricanes). Because the 2008 hurricane season seems destined to be one that is non-El Nino-related and is a post-1995 season, estimates of the frequencies of occurrence for the various subsets of storms should be above long-term averages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA598320','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA598320"><span>Western North Pacific <span class="hlt">Tropical</span> <span class="hlt">Cyclone</span> Formation and Structure Change in TCS08</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2013-09-30</p> <p>define the final extratropical stage of the extratropical transition process (Quinting et al. 2013). In this case, the warm conveyor belt, cold... conveyor belt, and dry air stream were identified in relation to air that originated in the <span class="hlt">tropical</span> <span class="hlt">cyclone</span> or air that originated at upper levels and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMNG32A..02O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMNG32A..02O"><span>Thermodynamics of <span class="hlt">Tropical</span> <span class="hlt">Cyclones</span>: A Thermodynamic Approach to Nonlinear Non-equilibrium Phenomena</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ozawa, H.; Shimokawa, S.</p> <p>2016-12-01</p> <p>A formation process of circulatory motion of <span class="hlt">tropical</span> <span class="hlt">cyclones</span> is investigated from a thermodynamic viewpoint. The generation rate of mechanical energy