Gravity wave characteristics over Tromelin Island during the passage of cyclone Hudah

Chane-Ming, Fabrice; Roff, Greg; Robert, Laurent; Leveau, Jean

doi:10.1029/2001gl013286

Cited by 41 publications

(33 citation statements)

References 14 publications

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“…The wave trains propagating away from the main rainband may be viewed as the internal gravity waves radiating out of a thermal source. Previous observations (Pfister al., 1993;Sato, 1993;Chane-Ming et al, 2002, 2010Dhaka et al, 2003, Chun et et al, 2010) and numerical experiments (Kim et al, 2003;Kuester et al, 2008) supported the idea that internal gravity waves can be radiated away from tropical cyclones. This radiation is related to a tropical cyclone's strong sources of latent heat release.…”

Section: Model Simulation and Discussionmentioning

confidence: 65%

Mesoscale processes for super heavy rainfall of Typhoon Morakot (2009) over Southern Taiwan

et al. 2011

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Abstract.Within 100 h, a record-breaking rainfall, 2855 mm, was brought to Taiwan by typhoon Morakot in August 2009 resulting in devastating landslides and casualties. Analyses and simulations show that under favorable largescale situations, this unprecedented precipitation was caused first by the convergence of the southerly component of the pre-existing strong southwesterly monsoonal flow and the northerly component of the typhoon circulation. Then the westerly component of southwesterly flow pushed the highly moist air (mean specific humidity >16 g/kg between 950 and 700 hPa from NCEP GFS data set) eastward against the Central Mountain Range, and forced it to lift in the preferred area. From the fine-scale numerical simulation, not only did the convergence itself provide the source of the heavy rainfall when it interacted with the topography, but also convective cells existed within the typhoon's main rainband. The convective cells were in the form of small rainbands perpendicular to the main one, and propagated as wave trains downwind. As the main rainband moved northward and reached the southern CMR, convective cells inside the narrow convergence zone to the south and those to the north as wave trains, both rained heavily as they were lifted by the west-facing mountain slopes. Those mesoscale processes were responsible for the unprecedented heavy rainfall total that accompanied this typhoon.

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Section: Model Simulation and Discussionmentioning

confidence: 65%

Mesoscale processes for super heavy rainfall of Typhoon Morakot (2009) over Southern Taiwan

et al. 2011

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“…In summer, tropical cyclones are severe convective phenomena which directly affect Tromelin and La Réunion. They reveal to be significant sources of GW in the UT/LS above the south-west Indian basin (Chane-Ming et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

“…Mahé is the main island of Republic of Seychelles with a surface of 148 km 2 rising to 905 m near the equator. Tromelin is a 1 km 2 sandy desert island peaking at 7 m above the sea level (Chane-Ming et al, 2002). La Réunion with a surface of 2512 km 2 is located at the border of the tropical belt under tropical and subtropical conditions respectively during austral summer and during austral winter (Chane-Ming et al, 2000b).…”

Section: Experimental Datamentioning

confidence: 99%

Latitudinal and seasonal variability of gravity-wave energy in the South-West Indian Ocean

2007

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Abstract. Vertical temperature profiles obtained by radiosonde and Raman lidar measurements are used to investigate a climatology of total energy density of gravity waves (GW) in the Upper Troposphere (UT) and the Lower Stratosphere (LS) from 1992 to 2004 above Mahé (4 • S, 55 • E), Tromelin (15 • S, 54 • E) and La Réunion (21 • S, 55 • E) located in the tropical South-West Indian Ocean. The commonly used spectral index value (p≈5/3) of the intrinsic frequency spectrum is used for calculating estimated total energy density in the UT and LS. Estimated total energy density provides good estimation of total energy density in the LS but underestimates total energy density by one half in the UT above Mahé and Tromelin probably due to the activity of near-inertial frequency waves. Estimated total energy density reveals a strong seasonal variability as a function of latitude and convection as an evident active source of GW activity in the LS in austral summer. Above La Réunion, a semi-annual GW activity is observed in the LS with the signature of the subtropical barrier in the UT. Moreover, radiosondes and Raman lidar provide consistent GW surveys in the UT/LS at heights<23 km above La Réunion.

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“…Observations reveal that such GWs have horizontal wavelengths of 10-2000 km, vertical wavelengths of 1-6 km and periods of 1 h-2.5 days in the upper troposphere (UT) and the lower stratosphere (LS) above TC basins (Pfister et al, 1993;Sato et al, 1993;Chane Ming et al, 2002, 2010Dhaka et al, 2003;Niranjan Kumar et al, 2011;Das et al, 2012). Recently, using radiosonde data, Chane also demonstrated a possible correlation between daily maximum surface wind speed and total energy density of inertia GWs produced by intense TCs Dina and Faxai in the UT/LS.…”

Section: Introductionmentioning

confidence: 99%

Observation and a numerical study of gravity waves during tropical cyclone Ivan (2008)

et al. 2014

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Abstract. Gravity waves (GWs) with horizontal wavelengths of 32-2000 km are investigated during tropical cyclone (TC) Ivan (2008) in the southwest Indian Ocean in the upper troposphere (UT) and the lower stratosphere (LS) using observational data sets, radiosonde and GPS radio occultation data, ECMWF analyses and simulations of the French numerical model Meso-NH with vertical resolution < 150 m near the surface and 500 m in the UT/LS. Observations reveal dominant low-frequency GWs with short vertical wavelengths of 0.7-3 km, horizontal wavelengths of 80-400 km and periods of 4.6-13 h in the UT/LS. Continuous wavelet transform and image-processing tools highlight a wide spectrum of GWs with horizontal wavelengths of 40-1800 km, short vertical wavelengths of 0.6-3.3 km and periods of 20 min-2 days from modelling analyses. Both ECMWF and Meso-NH analyses are consistent with radiosonde and GPS radio occultation data, showing evidence of a dominant TCrelated quasi-inertia GW propagating eastward east of TC Ivan with horizontal and vertical wavelengths of 400-800 km and 2-3 km respectively in the LS, more intense during TC intensification. In addition, the Meso-NH model produces a realistic, detailed description of TC dynamics, some highfrequency GWs near the TC eye, variability of the tropospheric and stratospheric background wind and TC rainband characteristics at different stages of TC Ivan. A wave number 1 vortex Rossby wave is suggested as a source of dominant inertia GW with horizontal wavelengths of 400-800 km, while shorter scale modes (100-200 km) located at northeast and southeast of the TC could be attributed to strong localized convection in spiral bands resulting from wave number 2 vortex Rossby waves. Meso-NH simulations also reveal GWrelated clouds east of TC Ivan.

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Gravity wave characteristics over Tromelin Island during the passage of cyclone Hudah

Cited by 41 publications

References 14 publications

Mesoscale processes for super heavy rainfall of Typhoon Morakot (2009) over Southern Taiwan

Mesoscale processes for super heavy rainfall of Typhoon Morakot (2009) over Southern Taiwan

Latitudinal and seasonal variability of gravity-wave energy in the South-West Indian Ocean

Observation and a numerical study of gravity waves during tropical cyclone Ivan (2008)

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