Qualitative Discussion of Influences of some Factors on the Occurrence of Wind-Driven Coastal Upwelling Associated with “Aoshio” on the Northeast Shore of Tokyo Bay Using the Developed Analytical Model

2014 ◽  
Vol 641-642 ◽  
pp. 1040-1045
Author(s):  
Zhong Fan Zhu
Keyword(s):  
Analytical Model ◽  
Wind Shear ◽  
Coastal Upwelling ◽  
Tokyo Bay ◽  
Interfacial Friction ◽  
Observation Data ◽  
Shear Effect ◽  
Stratification Effect ◽  
Northeasterly Wind ◽  
Qualitative Discussion

An analytical model based on some solutions in the context of a two-layered fluid was developed to estimate the occurrence of northeasterly wind-driven coastal upwelling associated with “Aoshio” on the northeast shore of Tokyo Bay, and its validity was verified by comparing with observation data [1]. In this study, influences of all of the factors incorporated into this analytical model (including densities and thicknesses of the upper and lower layers, the parameter expressing the influences of interfacial friction and bottom friction) on the model are analyzed. The analytical model is found to express the competition between the wind-shear effect and the stratification effect: when the former dominates over the latter, Aoshio will occur on the northeast shore of the bay. The parameter that can be used to characterize the stratification effect can be simply expressed in terms of the product of density contrast and the square of thickness of the upper layer. Using different values of this parameter corresponding to different months in the model can simply estimate in which months it is easy for Aoshio phenomenon to happen on the northeast shore of the bay, and the result is roughly consistent with an observation phenomenon that Aoshio was frequently observed on the northeast shore of the bay in September and May and relatively less observed in June and July during 1978-2010.

scholarly journals Estimating the Occurrence of Wind-Driven Coastal Upwelling Associated with “Aoshio” on the Northeast Shore of Tokyo Bay, Japan: An Analytical Model

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Zhongfan Zhu ◽  
Jingshan Yu
Keyword(s):  
Surface Water ◽  
Analytical Model ◽  
Analytical Solutions ◽  
Coastal Upwelling ◽  
Tokyo Bay ◽  
Observation Data ◽  
Simple Analytical Model ◽  
Aquatic Animals ◽  
Bottom Oxygen ◽  
Layered Fluid

“Aoshio” in Tokyo Bay is a hydroenvironmental phenomenon in which seawater appears milky blue due to reflection of sunshine off surface water which contains lots of sulfur particles. Its appearance is due to coastal upwelling of bottom oxygen-depleted water, which causes many deaths of shellfish and other aquatic animals around the bay. In this study, we derived some analytical solutions in the context of a two-layered fluid and used them to make a simple analytical model to estimate the occurrence of “Aoshio” phenomenon on the northeast shore of Tokyo Bay. Comparison with observation data suggested that this model was valid to a certain degree.

scholarly journals Low-Level Wind Shear Identification along the Glide Path at BCIA by the Pulsed Coherent Doppler Lidar

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 50
Author(s):  
Hongwei Zhang ◽  
Xiaoying Liu ◽  
Qichao Wang ◽  
Jianjun Zhang ◽  
Zhiqiang He ◽  
...  
Keyword(s):  
Wind Shear ◽  
Vertical Direction ◽  
Small Scale ◽  
Observation Data ◽  
Doppler Lidar ◽  
Low Level ◽  
Glide Path ◽  
Coherent Doppler Lidar ◽  
Scanning Strategies ◽  
Meteorological Phenomenon

Low-level wind shear is usually to be a rapidly changing meteorological phenomenon that cannot be ignored in aviation security service by affecting the air speed of landing and take-off aircrafts. The lidar team in Ocean University of China (OUC) carried out the long term particular researches on the low-level wind shear identification and regional wind shear inducement search at Beijing Capital International Airport (BCIA) from 2015 to 2020 by operating several pulsed coherent Doppler lidar (PCDL) systems. On account of the improved glide path scanning strategy and virtual multiple wind anemometers based on the rang height indicator (RHI) modes, the small-scale meteorological phenomenon along the glide path and/or runway center line direction can be captured. In this paper, the device configuration, scanning strategies, and results of the observation data are proposed. The algorithms to identify the low-level wind shear based on the reconstructed headwind profiles data have been tested and proved based on the lidar data obtained from December 2018 to January 2019. High spatial resolution observation data at vertical direction are utilized to study the regional wind shear inducement at the 36L end of BCIA under strong northwest wind conditions.

Wind shear effect induced by the platform pitch motion of a spar-type floating wind turbine

2019 ◽  
Vol 135 ◽  
pp. 1186-1199 ◽  
Author(s):  
Binrong Wen ◽  
Xinliang Tian ◽  
Qi Zhang ◽  
Xingjian Dong ◽  
Zhike Peng ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Shear ◽  
Shear Effect ◽  
Pitch Motion ◽  
Floating Wind Turbine

scholarly journals Summer Wind Effects on Coastal Upwelling in the Southwestern Yellow Sea

2021 ◽  
Vol 9 (9) ◽  
pp. 1021
Author(s):  
Bin Wang ◽  
Lei Wu ◽  
Ning Zhao ◽  
Tianran Liu ◽  
Naoki Hirose
Keyword(s):  
Summer Monsoon ◽  
Wind Stress ◽  
Yellow Sea ◽  
Coastal Upwelling ◽  
Circulation Model ◽  
Tidal Mixing ◽  
The Yellow Sea ◽  
Observation Data ◽  
Wind Stress Curl ◽  
Green Tides

The features of coastal upwelling in the southwestern Yellow Sea were investigated based on oceanology data from a research cruise and a regional circulation model. The observation data suggest that a relatively colder and saltier water core exists from the deeper layer to the surface, off the Subei Bank. The concentrations of nutrients also suggest that coastal upwelling is beneficial for nutrient enrichment in the upper layer. The numerical simulations are in good agreement with oceanology observations. Furthermore, sensitivity experiments indicate that, in addition to the tidal-induced upwelling and tidal mixing proposed in previous studies, the summer monsoon is also critical to vertical circulation in the southwestern Yellow Sea. The southwesterly wind stress and positive wind stress curl make considerable contributions to upwelling off the Subei coast compared with tidal motions. Moreover, this study also proposes that changes in the summer monsoon and its curl may have been helpful to the formation of upwelling during the past decade, which may have provided a favorable marine environment for the frequent occurrence of green tides. This study provides a theoretical basis for the mechanisms of coastal upwelling and the nitrogen cycle in the Yellow Sea.

scholarly journals The age-stratified analytical model for the spread of the COVID-19 epidemic

2021 ◽  
Author(s):  
Felix Mairanowski ◽  
Denis Below
Keyword(s):  
Analytical Model ◽  
High Intensity ◽  
Age Groups ◽  
Observation Data ◽  
Age Group ◽  
Epidemic Spread ◽  
Intensity Of Infection ◽  
Good Correspondence ◽  
Contact Patterns ◽  
Comparison Of The Results

The previously developed ASILV model for calculating epidemic spread under conditions of lockdown and mass vaccination was modified to analyse the intensity of COVID-19 infection growth in the allocated age groups. Comparison of the results of calculations of the epidemic spread, as well as the values of the seven-day incidence values with the corresponding observation data, shows their good correspondence for each of the selected age groups. The greatest influence on the overall spread of the epidemic is in the 20-40 age groups. The relatively low level of vaccination and the high intensity of contact in these age groups contributes to the emergence of new waves of the epidemic, which is especially active when the virus mutates and the lockdown conditions are relaxed. The intensity of the epidemic in the 90+ age group has some peculiarities compared to other groups, which may be explained by differences in contact patterns among individuals in this age group compared to others. Approximate ratios for estimating mortality as a function of the intensity of infection for individual age groups are provided. The proposed stratified ASILV model by age group will allow more detailed and accurate prediction of the spread of the COVID-19 epidemic, including when new, more transmissible versions of the virus mutate and emerge.

scholarly journals The Effect of Wind Shear and Curvature on the Gravity Wave Drag Produced by a Ridge

2004 ◽  
Vol 61 (21) ◽  
pp. 2638-2643 ◽  
Author(s):  
Miguel A. C. Teixeira ◽  
Pedro M. A. Miranda
Keyword(s):  
Gravity Wave ◽  
Analytical Model ◽  
Wind Shear ◽  
Stratified Flow ◽  
Wave Drag ◽  
Mountain Ridge ◽  
Vertical Variation ◽  
Hydrostatic Approximation

Abstract The analytical model proposed by Teixeira, Miranda, and Valente is modified to calculate the gravity wave drag exerted by a stratified flow over a 2D mountain ridge. The drag is found to be more strongly affected by the vertical variation of the background velocity than for an axisymmetric mountain. In the hydrostatic approximation, the corrections to the drag due to this effect do not depend on the detailed shape of the ridge as long as this is exactly 2D. Besides the drag, all the perturbed quantities of the flow at the surface, including the pressure, may be calculated analytically.

The Optimal Wind Direction for the Occurrence of Wind-Driven Coastal Upwelling Associated with “Aoshio” on the Southeast Shore of Tokyo Bay

2014 ◽  
Vol 641-642 ◽  
pp. 1046-1050
Author(s):  
Zhong Fan Zhu
Keyword(s):  
Coriolis Force ◽  
Wind Direction ◽  
Coastal Upwelling ◽  
Tokyo Bay ◽  
Long Channel ◽  
Layered Fluid

Whether the optimal wind direction for the occurrence of wind-driven coastal upwelling associated with "Aoshio" on the southeast shore of Tokyo Bay exists was not clear. In this study, Tokyo Bay was assumed to be a narrow, infinitely long channel with only the southeast shore and the northwest shore being its two boundaries, and the optimal wind direction for coastal upwelling associated with "Aoshio" on the southeast shore of this idealized channel was discussed. It is found that the optimal wind direction varies with wind duration. If wind duration is very short, the optimal wind direction is almost across the channel while, with the increasing wind duration, the optimal wind direction approaches gradually to be along-channel. This transition is attributed to the increasingly important role that played by the Coriolis force in the motion of the two-layered fluid with the increasing wind duration.

scholarly journals Applying a Simple Analytical Solution to Modelling Wind-Driven Coastal Upwelling of Two-Layered Fluid at the Head of Tokyo Bay, Japan

Water ◽  
2017 ◽  
Vol 9 (10) ◽  
pp. 744 ◽  
Author(s):  
Zhongfan Zhu ◽  
Xiaomei Bai ◽  
Jie Dou ◽  
Pengfei Hei
Keyword(s):  
Analytical Solution ◽  
Coastal Upwelling ◽  
Tokyo Bay ◽  
Layered Fluid
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