Exploring rainfall kinetic energy induced erosion behavior and sediment sorting for a coarse-textured granite derived soil of south China

2021 ◽  
Vol 208 ◽  
pp. 104915
Author(s):  
S.M. Ni ◽  
D.Q. Zhang ◽  
C.F. Cai ◽  
G.V. Wilson ◽  
J.H. Zhang ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
South China ◽  
Erosion Behavior ◽  
Sediment Sorting

scholarly journals Budgets of rotational and divergent kinetic energy in the warm-sector torrential rains over South China: a case study

2021 ◽  
Author(s):  
Shui-Xin Zhong ◽  
Wei-Guang Meng ◽  
Fu-You Tian
Keyword(s):  
Kinetic Energy ◽  
Energy Budget ◽  
South China ◽  
Extreme Precipitation ◽  
Flux Divergence ◽  
Low Level ◽  
Warm Sector ◽  
Kinetic Energy Budget ◽  
Rotational Components ◽  
The Pearl River

AbstractThe contributions of divergent and rotational wind components to the kinetic energy budget during a record-breaking rainstorm on 7 May 2017 over South China are examined. This warm-sector extreme precipitation caused historical maximum of 382.6 mm accumulated rainfall in 3 h over the Pearl River Delta (PRD) regions in South China. Results show that there was a high low-level southerly wind-speed tongue stretching into the PRD regions from the northeast of the South China Sea (SCS) during this extreme precipitation. The velocity potential exhibited a low-value center as well as a low-level divergence-center over the SCS. The rotational components of the kinetic energy (KR)-related terms were the main contribution-terms of the kinetic energy budget. The main contribution-terms of KR and the divergent component of kinetic energy (KD) were the barotropical and baroclinic processes-related terms due to cross-contour flow and the vertical flux divergence.

scholarly journals Correlation of Near-Inertial Wind Stress in Typhoon and Typhoon-Induced Oceanic Near-Inertial Kinetic Energy in the Upper South China Sea

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 388
Author(s):  
Li ◽  
Xu ◽  
Liu ◽  
He ◽  
Chen ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
South China Sea ◽  
Wind Energy ◽  
Wind Stress ◽  
South China ◽  
Translation Speed ◽  
China Sea ◽  
Typhoon Track ◽  
Upper South ◽  
Inertial Currents

The correlation of near-inertial wind stress (NIWS) in typhoon and typhoon-induced oceanic near-inertial kinetic energy (NIKE) in the upper South China Sea (SCS) is investigated through reanalysis data and an idealized typhoon model. It is found that the typhoon-induced oceanic near-inertial currents are primarily induced by the NIWS, which may contribute to about 80% of the total NIKE induced by typhoon. The intensities and distributions of NIWS in most typhoons are consistent with the magnitudes and features of NIKE. The NIWS and the NIKE along the typhoon track have positive correlations with the maximum wind speed of a typhoon, but there is an optimal translation speed for NIWS, at which the wind energy of the near-inertial band reaches its maximum. In the idealized typhoon model, a cluster of high-value centers of NIWS appear along the typhoon track, but there is only one high-value center for the near-inertial currents. The maximum NIWS arrives about 15 hours prior to the maximum near-inertial current. The distribution of NIWS is apparently asymmetric along the typhoon track, which may be due to the smaller eastward component of wind energy.

scholarly journals Observations of Shoaling Internal Wave Transformation Over a Gentle Slope in the South China Sea

2021 ◽  
Author(s):  
Steven R. Ramp ◽  
Yiing Jang Yang ◽  
Ching-Sang Chiu ◽  
D. Benjamin Reeder ◽  
Frederick L. Bahr
Keyword(s):  
Kinetic Energy ◽  
South China Sea ◽  
Energy Flux ◽  
South China ◽  
The South China Sea ◽  
Wave Transformation ◽  
Recent Theory ◽  
The South ◽  
China Sea ◽  
The Waves

Abstract. Four oceanographic moorings were deployed across the South China Sea continental slope near 21.85° N, 117.71° E, from May 30 to July 18, 2014 for the purpose of observing high-frequency nonlinear internal waves (NLIWs) as they shoaled across a rough, gently sloping bottom. Individual waves required just two hours to traverse the array and could thus easily be tracked from mooring-to-mooring. In general, the amplitude of the incoming NLIWs was a good match with the fortnightly tidal envelope in the Luzon Strait, lagged by 48.5 hours, and were smaller than the waves observed 50 km to the southwest near the Dongsha Plateau. The now-familiar type a-waves and b-waves were observed, with the b-waves always leading the a-waves by 6–8 hours. Most of the waves were remotely generated, but a few of the b-waves formed locally via convergence and breaking at the leading edge of the upslope internal tide. Waves incident upon the array with amplitude less than 50 m and energy less than 100 MJ m−1 propagated adiabatically upslope with little change of form. Larger waves formed packets via wave dispersion. For the larger waves, the kinetic energy flux decreased sharply upslope between 342 m to 266 m while the potential energy flux increased slightly, causing an increasing ratio of potential-to-kinetic energy as the waves shoaled. The results are in rough agreement with recent theory and numerical simulations of shoaling waves.

scholarly journals Kinetic Energy Budget during the Genesis Period of Tropical Cyclone Durian (2001) in the South China Sea

2016 ◽  
Vol 144 (8) ◽  
pp. 2831-2854 ◽  
Author(s):  
Yaping Wang ◽  
Xiaopeng Cui ◽  
Xiaofan Li ◽  
Wenlong Zhang ◽  
Yongjie Huang
Keyword(s):  
Tropical Cyclone ◽  
Kinetic Energy ◽  
South China Sea ◽  
Latent Heat ◽  
Energy Budget ◽  
South China ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Stage Stage

Abstract A set of kinetic energy (KE) budget equations associated with four horizontal flow components was derived to study the KE characteristics during the genesis of Tropical Cyclone (TC) Durian (2001) in the South China Sea using numerical simulation data. The genesis process was divided into three stages: the monsoon trough stage (stage 1), the midlevel mesoscale convective vortex (MCV) stage (stage 2), and the establishment stage of the TC vortex (stage 3). Analysis showed that the KE of the symmetric rotational flow (SRF) was the largest and kept increasing, especially in stages 2 and 3, representing the symmetrization process during TC genesis. The KE of the SRF was mainly converted from the KE of the symmetric divergent flow (SDF), largely transformed from the available potential energy (APE). It was found that vortical hot towers (VHTs) emerged abundantly, aggregated, and merged within the MCV region in stages 1 and 2. From the energy budget perspective, massive moist-convection-produced latent heat was concentrated and accumulated within the MCV region, especially in stage 2, and further warmed the atmosphere, benefiting the accumulation of APE and the transformation from APE to KE. As a result, the midlevel circulation (or MCV) grew strong rapidly. In stage 3, the intensity and number of VHTs both decreased. However, affected by increasing lower-level inward radial wind, latent heat released by the organized convection, instead of disorganized VHTs in the first two stages, continuously contributed to the strengthening of the surface TC circulation as well as the warm core.

scholarly journals Physical modulation to the biological productivity in the summer Vietnam upwelling system

Ocean Science ◽  
2018 ◽  
Vol 14 (5) ◽  
pp. 1303-1320 ◽  
Author(s):  
Wenfang Lu ◽  
Lie-Yauw Oey ◽  
Enhui Liao ◽  
Wei Zhuang ◽  
Xiao-Hai Yan ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
South China Sea ◽  
Ocean Circulation ◽  
South China ◽  
Coastal Upwelling ◽  
Coupled Model ◽  
Biological Productivity ◽  
High Productivity ◽  
China Sea ◽  
Upwelling System

Abstract. Biological productivity in the summer Vietnam boundary upwelling system in the western South China Sea, as in many coastal upwelling systems, is strongly modulated by wind. However, the role of ocean circulation and mesoscale eddies has not been elucidated. Here, we show a close spatiotemporal covariability between primary production and kinetic energy. High productivity is associated with high kinetic energy, which accounts for ∼15 % of the production variability. Results from a physical–biological coupled model reveal that the elevated kinetic energy is linked to the strength of the current separation from the coast. In the low production scenario, the circulation is not only weaker but also shows weak separation. In the higher production case, the separated current forms an eastward jet into the interior South China Sea, and the associated southern recirculation traps nutrients and favors productivity. When separation is absent, the model shows weakened circulation and eddy activity, with ∼21 % less nitrate inventory and ∼16 % weaker primary productivity.

scholarly journals Physical Modulation to the Biological Productivity in the Summer Vietnam Upwelling System

2018 ◽  
Author(s):  
Wenfang Lu ◽  
Enhui Liao ◽  
Xiao-Hai Yan ◽  
Lie-Yauw Oey ◽  
Wei Zhuang ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
South China Sea ◽  
Ocean Circulation ◽  
South China ◽  
Coastal Upwelling ◽  
Current System ◽  
Coupled Model ◽  
Biological Productivity ◽  
China Sea ◽  
Upwelling System

Abstract. Biological productivity in the summer Vietnam boundary upwelling system in the western South China Sea, as in many coastal upwelling systems, is strongly modulated by wind. However, the role of ocean circulation and mesoscale eddies has not been elucidated. Here we show a close spatio-temporal covariability between primary production and kinetic energy. High productivity is associated with high kinetic energy, which accounts for ~ 15 % of the production variability. Results from a physical-biological coupled model reveal that the elevated kinetic energy and intensified circulation can be explained by the separation of the upwelling current system. The separated current forms an eastward jet into the interior South China Sea, and the associated southern gyre traps nutrient and favors productivity. When separation is absent, the model shows weakened circulation and eddy activity, with ~ 21 % less nitrate inventory and ~ 16 % weaker primary productivity.

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