Modeling of Typhoon Tracks through Interactions with Background Wind Vortices

Abstract. Gravity waves play a significant role in driving the semiannual oscillation (SAO) of the zonal wind in the tropics. However, detailed knowledge of this forcing is missing, and direct estimates from global observations of gravity waves are sparse. For the period 2002–2018, we investigate the SAO in four different reanalyses: ERA-Interim, JRA-55, ERA-5, and MERRA-2. Comparison with the SPARC zonal wind climatology and quasi-geostrophic winds derived from Microwave Limb Sounder (MLS) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite observations show that the reanalyses reproduce some basic features of the SAO. However, there are also large differences, depending on the model setup. Particularly, MERRA-2 seems to benefit from dedicated tuning of the gravity wave drag parameterization and assimilation of MLS observations. To study the interaction of gravity waves with the background wind, absolute values of gravity wave momentum fluxes and a proxy for absolute gravity wave drag derived from SABER satellite observations are compared with different wind data sets: the SPARC wind climatology; data sets combining ERA-Interim at low altitudes and MLS or SABER quasi-geostrophic winds at high altitudes; and data sets that combine ERA-Interim, SABER quasi-geostrophic winds, and direct wind observations by the TIMED Doppler Interferometer (TIDI). In the lower and middle mesosphere the SABER absolute gravity wave drag proxy correlates well with positive vertical gradients of the background wind, indicating that gravity waves contribute mainly to the driving of the SAO eastward wind phases and their downward propagation with time. At altitudes 75–85 km, the SABER absolute gravity wave drag proxy correlates better with absolute values of the background wind, suggesting a more direct forcing of the SAO winds by gravity wave amplitude saturation. Above about 80 km SABER gravity wave drag is mainly governed by tides rather than by the SAO. The reanalyses reproduce some basic features of the SAO gravity wave driving: all reanalyses show stronger gravity wave driving of the SAO eastward phase in the stratopause region. For the higher-top models ERA-5 and MERRA-2, this is also the case in the lower mesosphere. However, all reanalyses are limited by model-inherent damping in the upper model levels, leading to unrealistic features near the model top. Our analysis of the SABER and reanalysis gravity wave drag suggests that the magnitude of SAO gravity wave forcing is often too weak in the free-running general circulation models; therefore, a more realistic representation is needed.

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Impact of the Boreal Summer Intraseasonal Oscillation on Typhoon Tracks in the Western North Pacific and the Prediction Skill of the ECMWF model.

Geophysical Research Letters ◽

10.1029/2020gl091505 ◽

2021 ◽

Author(s):

M. Nakano ◽

F. Vitart ◽

K. Kikuchi

Keyword(s):

North Pacific ◽

Western North Pacific ◽

Intraseasonal Oscillation ◽

Prediction Skill ◽

Boreal Summer ◽

Boreal Summer Intraseasonal Oscillation ◽

Typhoon Tracks ◽

Ecmwf Model

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Retrieving clear-air turbulence information from regular commercial aircraft using Mode-S and ADS-B broadcast

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-8-11817-2015 ◽

2015 ◽

Vol 8 (11) ◽

pp. 11817-11852 ◽

Cited By ~ 2

Author(s):

J. M. Kopeć ◽

K. Kwiatkowski ◽

S. de Haan ◽

S. P. Malinowski

Keyword(s):

Dissipation Rate ◽

Vertical Acceleration ◽

Background Wind ◽

Commercial Aircraft ◽

Processing Methods ◽

Turbulence Measurements ◽

Significant Potential ◽

Air Turbulence ◽

Research Aircraft ◽

Comparison Of The Results

Abstract. Navigational information broadcast by commercial aircraft in the form of Mode-S and ADS-B messages can be considered a new and valid source of upper air turbulence measurements. A set of three processing methods is proposed and analysed using a quality record of turbulence encounters made by a research aircraft. The proposed methods are based on processing the vertical acceleration or the background wind into the eddy dissipation rate. All the necessary parameters are conveyed in the Mode-S/ADS-B messages. The comparison of the results of application of the processing against a reference eddy dissipation rate obtained using on-board accelerometer indicate a significant potential of those methods. The advantages and limitation of the presented approaches are discussed.

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

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-10757-2013 ◽

2013 ◽

Vol 13 (4) ◽

pp. 10757-10807 ◽

Cited By ~ 1

Author(s):

F. Chane Ming ◽

C. Ibrahim ◽

S. Jolivet ◽

P. Keckhut ◽

Y.-A. Liou ◽

...

Keyword(s):

Tropical Cyclone ◽

Gravity Waves ◽

High Frequency ◽

Lower Stratosphere ◽

Numerical Study ◽

Wide Spectrum ◽

Spectral Characteristics ◽

Background Wind ◽

Quasi Biennial Oscillation ◽

North East

Abstract. Activity and spectral characteristics of gravity-waves (GWs) are analyzed during tropical cyclone (TC) Ivan (2008) in the troposphere and lower stratosphere using radiosonde and GPS radio occultation data, ECMWF outputs and simulations of French numerical model Meso-NH with vertical resolution varying between 150 m near the surface and 500 m in the lower stratosphere. Conventional methods for GW analysis and signal and image processing tools provide information on a wide spectrum of GWs with horizontal wavelengths of 40–1800 km and short vertical wavelengths of 0.6–10 km respectively and periods of 20 min–2 days. MesoNH model, initialized with Aladin-Réunion analyses, produces realistic and detailed description of TC dynamics, GWs, variability of the tropospheric and stratospheric background wind and TC rainband characteristics at different stages of TC Ivan. In particular a dominant eastward propagating TC-related quasi-inertia GW is present during intensification of TC Ivan with horizontal and vertical wavelengths of 400–600 km and 1.5–3.5 km respectively during intensification. A wavenumber-1 vortex Rossby wave is identified as a source of this medium-scale mode while short-scale modes located at north-east and south-east of the TC could be attributed to strong localized convection in spiral bands resulting from wavenumber-2 vortex Rossby waves. Meso-NH simulations also reveal high-frequency GWs with horizontal wavelengths of 20–80 km near the TC eye and high-frequency GWs-related clouds behind TC Ivan. In addition, GWs produced during landfall are likely to strongly contribute to background wind in the middle and upper troposphere as well as the stratospheric quasi-biennial oscillation.

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The impact of different historical typhoon tracks on storm surge: A case study of Zhejiang, China

Journal of Marine Systems ◽

10.1016/j.jmarsys.2020.103318 ◽

2020 ◽

Vol 206 ◽

pp. 103318 ◽

Cited By ~ 1

Author(s):

Mei Du ◽

Yijun Hou ◽

Peng Qi ◽

Kai Wang

Keyword(s):

Storm Surge ◽

Typhoon Tracks ◽

The Impact

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Towing Test Data Set of the Kyushu University Kite System

Data ◽

10.3390/data5030069 ◽

2020 ◽

Vol 5 (3) ◽

pp. 69

Author(s):

Mostafa A. Rushdi ◽

Tarek N. Dief ◽

Shigeo Yoshida ◽

Roland Schmehl

Keyword(s):

Measurement Data ◽

Control Unit ◽

Straight Runway ◽

Background Wind ◽

Data Set ◽

Present Measurement ◽

Environmental Footprints ◽

Flight Mode ◽

Lower Material ◽

Traction Power

Kites can be used to harvest wind energy with substantially lower material and environmental footprints and a higher capacity factor than conventional wind turbines. In this paper, we present measurement data from seven individual tow tests with the kite system developed by Kyushu University. This system was designed for 7 kW traction power and comprises an inflatable wing of 6 m2 surface area with a suspended kite control unit that is towed on a relatively short tether of 0.4 m by a truck driving at constant speed along a straight runway. To produce a controlled relative flow environment, the experiment was conducted only when the background wind speed was negligible. We recorded the time-series of 11 different sensor values acquired on the kite, the control unit and the truck. The measured data can be used to assess the effects of the towing speed, the flight mode and the lengths of the control lines on the tether force.

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Interacting urban heat island circulations as affected by weak background wind

Building and Environment ◽

10.1016/j.buildenv.2019.106224 ◽

2019 ◽

Vol 160 ◽

pp. 106224 ◽

Cited By ~ 2

Author(s):

Qun Wang ◽

Yifan Fan ◽

Jian Hang ◽

Yuguo Li

Keyword(s):

Urban Heat Island ◽

Heat Island ◽

Background Wind ◽

Urban Heat

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Dynamics of Mechanical Oscillator Mechanism for Stratospheric Gravity Waves Generated by Convection

Atmosphere ◽

10.3390/atmos11090942 ◽

2020 ◽

Vol 11 (9) ◽

pp. 942

Author(s):

Shiwang Yu ◽

Lifeng Zhang ◽

Ming Zhang ◽

Yuan Wang

Keyword(s):

Gravity Waves ◽

Boussinesq Approximation ◽

Generation Mechanism ◽

Buoyancy Frequency ◽

Background Wind ◽

Dynamics Model ◽

Mechanical Oscillator ◽

Vortex System ◽

Wave Resonance ◽

Intrinsic Characteristic

The mechanical oscillator mechanism (MOM) for stratospheric gravity waves generated by convection is investigated with a dynamics model using the two-dimensional, nonhydrostatic and linear governing equations based on the Boussinesq approximation. The model is solved analytically with a fixed buoyancy oscillation (BO) at the tropopause as the boundary conditions. Results show that this BO is the source of stratospheric gravity waves and the MOM is the generation mechanism. The characteristics of the stratospheric gravity waves not only depend on the BO, but also rely on the stratospheric state, such as the background wind and the buoyancy frequency. When the vertical wavenumbers of the stratospheric gravity waves are close to those of the intrinsic characteristic waves (ICWs), which are the model solution without BO forcing at the tropopause, resonance occurs. Under the resonance conditions, the amplitudes of the stratospheric gravity waves increase significantly, even for low BO intensity. The background wind in the stratosphere has a large effect on wave resonance. Finally, numerical simulation results of a low-vortex system also verify that the MOM is the generation mechanism of stratospheric gravity waves generated by convection.

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