Southern hemisphere tropical cyclone intensity forecast methods used at the Joint Typhoon Warning Center, Part II: statistical-dynamical forecasts

Knaff, John A.; Sampson, Charles R.

doi:10.22499/2.5801.002

Cited by 21 publications

(45 citation statements)

References 37 publications

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“…These have been reanalyzed postseason (i.e., best tracked) beginning in 2004 (Knaff et al 2007). concurrent time.…”

Section: Methodsmentioning

confidence: 99%

“…This metric is used as a measure of TC energy, noting that frictional velocity, where available, is better related to oceanic mixing balances (Phillips 1977;Kraus and Turner 1967;Pollard et al 1973). The radius of maximum winds follows the calculations in Knaff et al (2007) …”

Section: Methodsmentioning

confidence: 99%

“…A factor of 0.85 is used to account for some of the high bias in r max estimates (Knaff et al 2007). The formula y srm 5 y max 2 1.5c 0.63 assumes that the intensity (y max ) and translation speed (c) have units of knots following the Schwerdt et al (1979) asymmetry factor.…”

Section: Methodsmentioning

confidence: 99%

“…3 (bottom left) the intensity-based composites show that the 10-day lagged SST cooling associated with a strong tropical storm is 0.48C, nearly twice that for a hurricane/typhoon. Another interesting feature is the greater cooling in the Atlantic storms in the 60-to 100-kt range of intensities, which may be an artifact related to the tendency for hurricanes to grow while weakening and moving northward (Merrill 1984;Knaff et al 2007;Maclay et al 2008). In the western North Pacific results show that the most cooling is associated with the most intense TCs, which may suggest that the most intense TCs in that basin occur in a region more susceptible to mixing, move slower, or have larger wind fields than in other basins.…”

Section: A Initial Ocean Responsementioning

confidence: 99%

“…Empirical relationships have been developed that describe TC potential intensity as a function of SSTs for various TC basins (Merrill 1987;DeMaria and Kaplan 1994;Whitney and Hobgood 1997;Knaff et al 2005;Knaff and Sampson 2009). Many empirical and theoretical models of potential intensity have also been developed (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Upper Oceanic Energy Response to Tropical Cyclone Passage

et al. 2013

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The upper oceanic temporal response to tropical cyclone (TC) passage is investigated using a 6-yr daily record of data-driven analyses of two measures of upper ocean energy content based on the U.S. Navy's Coupled Ocean Data Assimilation System and TC best-track records. Composite analyses of these data at points along the TC track are used to investigate the type, magnitude, and persistence of upper ocean response to TC passage, and to infer relationships between routinely available TC information and the upper ocean response. Upper oceanic energy decreases in these metrics are shown to persist for at least 30 days-long enough to possibly affect future TCs. Results also indicate that TC kinetic energy (KE) should be considered when assessing TC impacts on the upper ocean, and that existing TC best-track structure information, which is used here to estimate KE, is sufficient for such endeavors. Analyses also lead to recommendations concerning metrics of upper ocean energy. Finally, parameterizations for the lagged, along-track, upper ocean response to TC passage are developed. These show that the sea surface temperature (SST) is best related to the KE and the latitude whereas the upper ocean energy is a function of KE, initial upper ocean energy conditions, and translation speed. These parameterizations imply that the 10-day lagged SST cooling is approximately 0.78C for a ''typical'' TC at 308 latitude, whereas the same storm results in 10-day (30-day) lagged decreases of upper oceanic energy by about 12 (7) kJ cm 22 and a 0.58C (0.38C) cooling of the top 100 m of ocean.

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“…These have been reanalyzed postseason (i.e., best tracked) beginning in 2004 (Knaff et al 2007). concurrent time.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: A Initial Ocean Responsementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Upper Oceanic Energy Response to Tropical Cyclone Passage

et al. 2013

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Is there a linkage between the tropical cyclone activity in the southern Indian Ocean and the Antarctic Oscillation?

et al. 2013

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[1] In this article, the relationship between the Antarctic Oscillation (AAO) and the tropical cyclone (TC) activity in the southern Indian Ocean (SIO) was examined. It was found that on the interannual time scale, the AAO is well linked with the TC activity in the SIO during TC season (December-March). The rank correlation coefficient between the AAO index and the TC frequency (TCF) in the SIO is 0.37, which is significant at the 95% confidence level. When the AAO is in a positive phase, TC passage in the northwestern coast of Australia (100E°-120°E and 10°S-30°S) increases by approximately 50%-100% from the climatology. The increase in the TC passage is primarily the result of more frequent TCs originating in this region due to enhanced water vapor convergence and ascending motions, which are caused by a cyclonic height anomaly over the western coast of Australia associated with the positive AAO phases. In addition, the AAO-height covariations, which are essential to the formation of the AAO-TC links in the SIO, were investigated through a historical climate simulation using the Community Climate System Model 4 from the Coupled Model Intercomparison Project Phase 5. The AAO-height links were well reproduced in the simulation. The similarity in the AAO-height links between the observation and the simulation supports the physical robustness of the AAO-TC links in the SIO.

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Stochastic event set generation for tropical cyclone using machine‐learning approach guided by environmental data

Bongirwar¹

2020

Intl Journal of Climatology

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Southern hemisphere tropical cyclone intensity forecast methods used at the Joint Typhoon Warning Center, Part II: statistical-dynamical forecasts

Cited by 21 publications

References 37 publications

Upper Oceanic Energy Response to Tropical Cyclone Passage

Upper Oceanic Energy Response to Tropical Cyclone Passage

Is there a linkage between the tropical cyclone activity in the southern Indian Ocean and the Antarctic Oscillation?

Stochastic event set generation for tropical cyclone using machine‐learning approach guided by environmental data

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