Relationship between oceanic energy fluxes and surface winds during tropical cyclone passage

2006 ◽  
pp. 115-142 ◽  
Author(s):  
L.K. Shay ◽  
S.D. Jacob
Keyword(s):  
Tropical Cyclone ◽  
Surface Winds ◽  
Energy Fluxes

scholarly journals Simulated Sensitivity of Tropical Cyclone Size and Structure to the Atmospheric Temperature Profile

2016 ◽  
Vol 73 (11) ◽  
pp. 4553-4571 ◽  
Author(s):  
Diana R. Stovern ◽  
Elizabeth A. Ritchie
Keyword(s):  
Tropical Cyclone ◽  
Surface Energy ◽  
Temperature Profile ◽  
Convective Available Potential Energy ◽  
Atmospheric Temperature ◽  
Outer Core ◽  
Specific Humidity ◽  
Energy Fluxes ◽  
Surface Energy Fluxes ◽  
Size And Structure

Abstract This study uses the WRF ARW to investigate how different atmospheric temperature environments impact the size and structure development of a simulated tropical cyclone (TC). In each simulation, the entire vertical virtual temperature profile is either warmed or cooled in 1°C increments from an initial specified state while the initial relative humidity profile and sea surface temperature are held constant. This alters the initial amount of convective available potential energy (CAPE), specific humidity, and air–sea temperature difference such that, when the simulated atmosphere is cooled (warmed), the initial specific humidity and CAPE decrease (increase), but the surface energy fluxes from the ocean increase (decrease). It is found that the TCs that form in an initially cooler environment develop larger wind and precipitation fields with more active outer-core rainband formation. Consistent with previous studies, outer-core rainband formation is associated with high surface energy fluxes, which leads to increases in the outer-core wind field. A larger convective field develops despite initializing in a low CAPE environment, and the dynamics are linked to a wider field of surface radial inflow. As the TC matures and radial inflow expands, large imports of relative angular momentum in the boundary layer continue to drive expansion of the TC’s overall size.

scholarly journals Analyzing Gaps in Hurricane Rain Coverage to Inform Future Satellite Proposals

2020 ◽  
Vol 12 (17) ◽  
pp. 2673
Author(s):  
Justin P. Stow ◽  
Mark A. Bourassa ◽  
Heather M. Holbach
Keyword(s):  
High Resolution ◽  
Tropical Cyclone ◽  
Drop Size ◽  
Low Pressure ◽  
Surface Winds ◽  
Pressure Center ◽  
Rain Drop ◽  
The Cost ◽  
Aircraft Data ◽  
Surface Observations

This study assesses where tropical cyclone (TC) surface winds can be measured as a function of footprint sizes and wavelengths (Ka- Ku- and C-band). During TCs, most high-resolution surface observations are impeded by considerable ‘rain contamination.’ Under these conditions, high-resolution surface observations typically come from operational aircraft. Other techniques that provide high-resolution surface observations through rain are also hindered somewhat by rain contamination and are very sparse in space and time. The impacts of rain are functions of the remotely sensed wavelength and rain–drop size. Therefore, relative long wavelengths have been used to observe the surface, but at the cost of a larger footprint. We examine how smaller footprint sizes could be used to observe through gaps between moderate to heavy rainbands that circulate around the main low-pressure center of a TC. Aircraft data from the National Oceanic and Atmospheric Administration’s (NOAA’s) WP-3D turboprop aircraft will be used to create realistic maps of rain. Our results provide information on the satellite instrument characteristics needed to see the surface through these gaps. This information is expected to aid in developing hurricane-related applications of new higher-resolution satellites.

Synergistic Observations of Surface Winds and Currents in Tropical Cyclone

2021 ◽  
Author(s):  
Shengren Fan ◽  
Xu Yang ◽  
Shiyu Xue ◽  
Biao Zhang
Keyword(s):  
Tropical Cyclone ◽  
Surface Winds

scholarly journals The Response of Damaging Winds of a Simulated Tropical Cyclone to Finite-Amplitude Perturbations of Different Variables

2006 ◽  
Vol 63 (7) ◽  
pp. 1924-1937 ◽  
Author(s):  
R. N. Hoffman ◽  
J. M. Henderson ◽  
S. M. Leidner ◽  
C. Grassotti ◽  
T. Nehrkorn
Keyword(s):  
Tropical Cyclone ◽  
Data Assimilation ◽  
Vertical Velocity ◽  
A Priori ◽  
Finite Amplitude ◽  
Horizontal Wind ◽  
Wind Component ◽  
Surface Winds ◽  
Prognostic Variables ◽  
Perturbation Pressure

Abstract Four-dimensional variational data assimilation (4DVAR) is an established data assimilation method that finds the finite-amplitude perturbation that best fits observations consistent with a priori information and model dynamics. The response of a simulated tropical cyclone to specially designed finite perturbations of selected model variables was studied with a modified version of 4DVAR. The usual goal of minimizing data misfits was replaced with a goal of reducing damaging surface winds at the end of six hours of forecast time. For this purpose a property value cost function based on topography was defined. The case studied was a 20-km simulation of a hurricane approaching the Hawaiian Islands. Each prognostic variable in turn—temperature, winds, humidity, vertical velocity, and perturbation pressure—and all prognostic variables at once were used as the control vector for the optimization problem. Of all prognostic variables examined, temperature and the horizontal wind were the most effective at reducing damaging surface winds. The wind-only perturbation was very similar to the wind component of the perturbation calculated when all prognostic variables were used at once. Calculated perturbations had scales of 0.25°C or 1 m s−1, but changes at a few grid points near the center of the storm were an order of magnitude greater. Vertical velocity and humidity perturbations alone were ineffective at reducing damaging winds. The perturbation pressure experiment failed to converge but did substantially reduce the damaging winds.

scholarly journals Evaluation of Wave Forecasts Consistent with Tropical Cyclone Warning Center Wind Forecasts

2013 ◽  
Vol 28 (1) ◽  
pp. 287-294 ◽  
Author(s):  
Charles R. Sampson ◽  
Paul A. Wittmann ◽  
Efren A. Serra ◽  
Hendrik L. Tolman ◽  
Jessica Schauer ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Wind Field ◽  
Weather Prediction ◽  
Surface Wind ◽  
Track Forecast ◽  
Surface Winds ◽  
Wave Fields ◽  
Wavewatch Iii ◽  
Surface Wind Field

Abstract An algorithm to generate wave fields consistent with forecasts from the official U.S. tropical cyclone forecast centers has been made available in near–real time to forecasters since summer 2007. The algorithm removes the tropical cyclone from numerical weather prediction model surface wind field forecasts, replaces the removed winds with interpolated values from surrounding grid points, and then adds a surface wind field generated from the official forecast into the background. The modified wind fields are then used as input into the WAVEWATCH III model to provide seas consistent with the official tropical cyclone forecasts. Although this product is appealing to forecasters because of its consistency and its superior tropical cyclone track forecast, there has been only anecdotal evaluation of resulting wave fields to date. This study evaluates this new algorithm for two years’ worth of Atlantic tropical cyclones and compares results with those of WAVEWATCH III run with U.S. Navy Operational Global Atmospheric Prediction System (NOGAPS) surface winds alone. Results show that the new algorithm has generally improved forecasts of maximum significant wave heights and 12-ft seas’ radii in proximity to tropical cyclones when compared with forecasts produced using only the NOGAPS surface winds.

Tropical Cyclone Outer Surface Winds Derived from Satellite Microwave Sounder Data

1980 ◽  
Vol 108 (2) ◽  
pp. 144-152 ◽  
Author(s):  
Stanley Q. Kidder ◽  
William M. Gray ◽  
Thomas H. Vonder Haar
Keyword(s):  
Tropical Cyclone ◽  
Outer Surface ◽  
Surface Winds ◽  
Satellite Microwave

scholarly journals Atmospheric boundary layer characteristics over the Pearl River Delta, China during summer 2006: measurement and model results

2011 ◽  
Vol 11 (2) ◽  
pp. 4807-4842 ◽  
Author(s):  
S. J. Fan ◽  
Q. Fan ◽  
W. Yu ◽  
X. Y. Luo ◽  
B. M. Wang ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Pearl River Delta ◽  
Pearl River ◽  
Land Breeze ◽  
Surface Winds ◽  
Wind Fields ◽  
Local Circulation ◽  
High Pollution ◽  
The Pearl River ◽  
Rainy Days

Abstract. Atmospheric conditions are often connected with the occurrence of high pollution episodes especially in urban areas. As part of the PRIDE-PRD2006 intensive campaign, atmospheric boundary layer (ABL) measurements were carried out at Qingyuan, Panyu and Xinken in the Pearl River Delta (PRD) from 1 July to 30 July of 2006. It was found that in summer, the surface winds in PRD are more controlled by the south, and there usually is vertical wind shear at the height of 800 m or so, therefore, PRD is often influenced by the tropical cyclone/typhoon. The subsidence and precipitation from a tropical cyclone will affect the air quality of PRD. Under the subsidence, the wind speed in ABL and the height of ABL will decrease and result in high level concentrations. When the background wind speed is small or calm, the wind profile at Panyu and Xinken change dramatically with height, which is perhaps caused by the local circulations, such as the sea land breeze. For more understanding about the ABL of PRD, the simulations by the WRF mesoscale model were used to analyse the ABL characteristics in PRD. From three kinds of weather condition simulations (subsidence days, rainy days and sunny days) by WRF model, it was found that the simulated temperature, wind fields in these three cases were moderately consistent with the measurements. The results show that the diurnal variation of ABL in subsidence days and sunny days are obvious, but the diurnal variation of ABL on rainy days is not obvious. The ABL is obviously affected by the local circulation and the features of ABL are different in various stations. A simulation focus on high pollution episode during the subsidence days from 12–15 July 2006, occurred under high pressure conditions, accompanied by a tropical cyclone "Bilis". Comparing the simulated vertical wind fields and temperature structure with the ABL measurements at Xinken, Panyu and Qingyuan station, it was found that, the modelled and measured atmospheric fields reveal that there are two different kinds of ABL characteristics in PRD: when the surface winds in PRD were light or almost calm, the local circulation was dominated, such as the sea-land breeze at Xinken station and the mountain-valley circulation at Qingyuan station. When the surface winds were strong, the stations were under the same background weather system and the wind directions were almost the same. Furthermore, the modelled results also suggest that the high Air Pollutant index (API) episode was caused predominately by subsidence.

Sign in / Sign up

Export Citation Format

Share Document