scholarly journals Aerosol Impacts on the Structure, Intensity, and Precipitation of the Landfalling Typhoon Saomai (2006)

2017 ◽  
Vol 122 (21) ◽  
pp. 11,825-11,842 ◽  
Author(s):  
Yi Qu ◽  
Baojun Chen ◽  
Jie Ming ◽  
Barry H. Lynn ◽  
Ming-Jen Yang
Keyword(s):  
Landfalling Typhoon ◽  
Typhoon Saomai

Characteristics of wind profiles in the landfalling typhoon boundary layer

2016 ◽  
Vol 149 ◽  
pp. 77-88 ◽  
Author(s):  
Lili Song ◽  
Wenchao Chen ◽  
Binglan Wang ◽  
Shiqun Zhi ◽  
Aijun Liu
Keyword(s):  
Boundary Layer ◽  
Wind Profiles ◽  
Landfalling Typhoon

scholarly journals A Study of the Effects of Anthropogenic Gaseous Emissions on the Microphysical Properties of Landfalling Typhoon Nida (2016) over China

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1322
Author(s):  
Lin Deng ◽  
Wenhua Gao ◽  
Yihong Duan ◽  
Chong Wu
Keyword(s):  
Potential Temperature ◽  
Vapor Condensation ◽  
Influential Factors ◽  
Gaseous Emissions ◽  
Base Level ◽  
Microphysical Properties ◽  
Prolonged Duration ◽  
Raindrop Size ◽  
Microphysical Processes ◽  
Landfalling Typhoon

Using the Weather Research and Forecasting model with chemistry module (WRF-Chem), Typhoon Nida (2016) was simulated to investigate the effects of anthropogenic gaseous emissions on the vortex system. Based on the Multi-resolution Emission Inventory for China (MEIC), three certain experiments were conducted: one with base-level emission intensity (CTRL), one with one-tenth the emission of SO2 (SO2_C), and one with one-tenth the emission of NH3 (NH3_C). Results show that the simulations reasonably reproduced the typhoon’s track and intensity, which were slightly sensitive to the anthropogenic gaseous emissions. When the typhoon was located over the ocean, a prolonged duration of raindrop growth and more precipitation occurred in CTRL run. The strongest updraft in CTRL is attributed to the maximum latent heating through water vapor condensation. During the landfalling period, larger (smaller) differential reflectivities in the main-core of the vortex were produced in NH3_C (SO2_C) run. Such opposite changes of raindrop size distributions may lead to stronger (weaker) rainfall intensity, and the ice-related microphysical processes and the relative humidity in low troposphere were two possible influential factors. Moreover, additional ten-member ensemble results in which white noise perturbations were added to the potential temperature field, indicated that the uncertainty of thermodynamic field in the current numerical model should not be ignored when exploring the impacts of aerosol on the microphysics and TC precipitation.

scholarly journals Single Doppler radar observation of the concentric eyewall in Typhoon Saomai, 2006, near landfall

2008 ◽  
Vol 35 (7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Kun Zhao ◽  
Wen-Chau Lee ◽  
Ben Jong-Dao Jou
Keyword(s):  
Doppler Radar ◽  
Radar Observation ◽  
Typhoon Saomai

scholarly journals Improvement in the Forecasting of Heavy Rainfall over South China in the DSAEF_LTP Model by Introducing the Intensity of the Tropical Cyclone

2020 ◽  
Vol 35 (5) ◽  
pp. 1967-1980
Author(s):  
Ding Chenchen ◽  
Fumin Ren ◽  
Yanan Liu ◽  
John L. McBride ◽  
Tian Feng
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
South China ◽  
Numerical Weather Prediction ◽  
Heavy Rainfall ◽  
Prediction Models ◽  
Weather Prediction ◽  
Numerical Weather ◽  
Landfalling Typhoon ◽  
Numerical Weather Prediction Models

AbstractThe intensity of the tropical cyclone has been introduced into the Dynamical-Statistical-Analog Ensemble Forecast (DSAEF) for Landfalling Typhoon (or tropical cyclone) Precipitation (DSAEF_LTP) model. Moreover, the accumulated precipitation prediction experiments have been conducted on 21 target tropical cyclones with daily precipitation ≥ 100 mm in South China from 2012 to 2016. The best forecasting scheme for the DSAEF_LTP model is identified, and the performance of the prediction is compared with three numerical weather prediction models (the European Centre for Medium-Range Weather Forecasts, the Global Forecast System, and T639). The forecasting ability of the DSAEF_LTP model for heavy rainfall (accumulated precipitation ≥ 250 and ≥100 mm) improves when the intensity of the tropical cyclone is introduced, giving some advantages over the three numerical weather prediction models. The selection of analog tropical cyclones with a maximum intensity (during precipitation over land) equaling to or higher than the initial intensity of the target tropical cyclone gives better forecasts. The prediction accuracy for accumulated precipitation is higher for tropical cyclones with higher intensity and higher observed precipitation, with in both cases positive linear correlations with the threat score.

scholarly journals Stratospheric Gravity Waves Generated by Typhoon Saomai (2006): Numerical Modeling in a Moving Frame Following the Typhoon

2010 ◽  
Vol 67 (11) ◽  
pp. 3617-3636 ◽  
Author(s):  
So-Young Kim ◽  
Hye-Yeong Chun
Keyword(s):  
Gravity Waves ◽  
Momentum Flux ◽  
Mesoscale Model ◽  
Horizontal Resolution ◽  
Moving Frame ◽  
Mature Stage ◽  
Small Scale ◽  
Background Wind ◽  
Spiral Bands ◽  
Typhoon Saomai

Abstract Stratospheric gravity waves generated by Typhoon Saomai (2006) were simulated using a mesoscale model in a moving frame of reference following the typhoon. Waves with large amplitudes appear near the domain center because of strong convection in the eyewall of the typhoon. Convection bands propagating outward from the storm center also generate waves propagating to the stratosphere. Convective forcing is significant in various propagation directions, with maximum power in slowly moving eastward components due to convection in the eyewall. The forcing exhibits large amplitude at a speed of 8–16 m s−1 in the eastward direction in which spiral bands are mainly developed. Induced gravity waves in the stratosphere are dominant in the eastward, northeastward, and southeastward propagation directions, since westward waves are mostly filtered by the background wind below z = 25 km. While the typhoon moves northwestward for 78 h, the wave characteristics vary through time depending on the evolution of the eyewall and spiral bands. Horizontal wavelengths of waves are longer in the mature and decaying stages than in the developing stage of the typhoon, likely because of a more dominant concentric eyewall in the mature and decaying stages. The spectral peak of the waves is at ∼20 km (∼50 km) horizontal wavelength in the developing (mature) stage, and the wave amplitudes are larger in the developing stages. The dominant contribution to the momentum flux is from waves with horizontal wavelengths longer than 80 km. Positive momentum flux decreases with overall height and the resultant positive drag can cause deceleration of northeasterly background wind. Sensitivity of the model results to horizontal resolution reveals that small-scale waves resolved in the present simulations with 3-km resolution cannot be fully represented with 9- or 27-km resolutions.

scholarly journals Surface Pressure Features of Landfalling Typhoon Rainbands and Their Possible Causes

2010 ◽  
Vol 67 (9) ◽  
pp. 2893-2911 ◽  
Author(s):  
Cheng-Ku Yu ◽  
Chia-Lun Tsai
Keyword(s):  
Tropical Cyclone ◽  
Surface Pressure ◽  
Doppler Radar ◽  
Pressure Fluctuations ◽  
Outer Edge ◽  
Moist Convection ◽  
Wave Dynamics ◽  
Landfalling Typhoon ◽  
Pressure Perturbations ◽  
Surface Observations

Abstract This study uses temporally high-resolution surface observations, Doppler radar, and micro rain radar to document the finescale features of the two landfalling rainbands associated with Typhoon Longwang (2005) as they passed over northern Taiwan. The present case allows a unique opportunity to investigate well-defined, convectively active tropical cyclone rainbands over land. In particular, the surface pressure fluctuations observed during the passage of the two rainbands and their possible causes are explored. The rainbands were predominantly convective in nature, with embedded stratiform precipitation outside their inner/outer edge. Analyses of surface observations show similar surface pressure fluctuations during the rainband’s passage. Low (high) pressure with relatively strong (weak) cross-band flow and warmer (colder) temperature was located inside the outer (inner) edge. Maximum (minimum) pressure perturbations were observed to be ∼1.5 (∼−1) mb, with smaller magnitudes (<∼0.4 mb) outside the outer/inner edge. In particular, the studied rainbands possess some wavelike characteristics such as outward propagation, undulations of surface pressure perturbations, and opposite phase relation between the surface pressure perturbations and the cross-band flow. Detailed analyses indicate that the combined effects of pressure perturbations produced by moist convection and those associated with wave activities initiated within the typhoon could explain the observed surface features. The present study provides observational evidence to support the importance of wave dynamics and their interactions with moist convection for the generation of surface pressure perturbations associated with the observed tropical cyclone rainbands.

scholarly journals An Observational Study of a Coastal Barrier Jet Induced by a Landfalling Typhoon

2019 ◽  
Vol 147 (12) ◽  
pp. 4589-4609
Author(s):  
Yu-Cheng Kao ◽  
Ben Jong-Dao Jou ◽  
Johnny C. L. Chan ◽  
Wen-Chau Lee
Keyword(s):  
Wind Speed ◽  
Blocking Effect ◽  
Maximum Wind Speed ◽  
Doppler Velocity ◽  
Maximum Wind ◽  
Coastal Barrier ◽  
Southern Branch ◽  
The Difference ◽  
Landfalling Typhoon ◽  
Northern Branch

Abstract In this study, the structure and evolution of a coastal barrier jet (CBJ) along the east coast of Taiwan is documented using operational Doppler radars. The formation of the CBJ was controlled by the flow regime associated with the approaching Typhoon Haitang (2005). The CBJ persisted for 6 h and was approximately 140 km long and 25 km wide. The northern branch of the CBJ had stronger winds with maximum wind speed 49–52 m s−1, a greater vertical extent with jet core between 1.0 and 2.5 km in height, and a more persistent jet signal than the southern branch with maximum wind speed 43–46 m s−1 and jet core between 1.0 and 2.0 km. We investigated the terrain blocking effect leading to the CBJ formation using an idealized simulation. A vortex resembling Haitang is constructed based on circulation retrieved from generalized velocity track display (GVTD) technique. The result of a no-terrain simulation reveals wind speed 10–22 m s−1 lower than the observed Doppler velocity. The difference suggests the enhanced wind speed along the coast was most likely due to the terrain blocking effect.

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