Maintenance of the South Asian jet wave train: eddy kinetic energy balance

2021 ◽  
Author(s):  
Xiuzhen Li
Keyword(s):  
Energy Balance ◽  
Kinetic Energy ◽  
South Asian ◽  
Wave Train ◽  
Eddy Kinetic Energy ◽  
The South

Spatio-Temporal Variability of the Eddy Kinetic Energy in the South Atlantic Ocean

2014 ◽  
Vol 11 (11) ◽  
pp. 2010-2014
Author(s):  
C. M. Cecilio ◽  
D. F. M. Gherardi ◽  
R. B. Souza ◽  
M. Correa-Ramirez
Keyword(s):  
Kinetic Energy ◽  
Atlantic Ocean ◽  
Temporal Variability ◽  
South Atlantic ◽  
Eddy Kinetic Energy ◽  
South Atlantic Ocean ◽  
The South ◽  
Spatio Temporal

Seasonal variations of eddy kinetic energy flux in the South Indian Countercurrent region

2020 ◽  
Vol 38 (5) ◽  
pp. 1464-1475
Author(s):  
Zhongqian Chen ◽  
Faming Wang ◽  
Jian Zheng ◽  
Yuxing Yang
Keyword(s):  
Kinetic Energy ◽  
Energy Flux ◽  
Seasonal Variations ◽  
Eddy Kinetic Energy ◽  
The South ◽  
South Indian

Modulation of South Asian Jet Wave Train on the Extreme Winter Precipitation over Southeast China: Comparison between 2015/16 and 2018/19

2020 ◽  
Vol 33 (10) ◽  
pp. 4065-4081
Author(s):  
Xiuzhen Li ◽  
Zhiping Wen ◽  
Wan-Ru Huang
Keyword(s):  
South Asian ◽  
North Atlantic ◽  
Wave Train ◽  
Storm Track ◽  
Winter Precipitation ◽  
The South ◽  
Wave Source ◽  
Southeast China ◽  
The North ◽  
Quarter Wavelength

AbstractTwo extremely wet winters in 2015/16 and 2018/19 over Southeast China are compared in this study. South-to-north discrepancies appear in the spatial distribution of precipitation, with anomalous precipitation centered over the southeast coast in 2015/16 and the lower reaches of Yangtze River valley in 2018/19, respectively. Both instances of enhanced precipitation are ascribed mainly to warm and moist advection from the south, with transport in 2015/16 partly by a deepened India–Burma trough to the west, whereas with transport in 2018/19 mainly by a subtropical western North Pacific anticyclone (WNPAC). Both the India–Burma trough and WNPAC are maintained by the wave trains propagating along the South Asian jet, which are zonally offset by a quarter-wavelength. Further study of the wave train sources in 2015/16 and 2018/19 shows that they both tend to originate from extremely strong storm-track activity over the North Atlantic but have different displacement. The former is located more northeastward than the mean storm track and is modulated by a strong positive NAO, whereas the latter lies over the midlatitude central North Atlantic along with a circumglobal teleconnection. These differences further result in a quarter-wavelength offset in the Rossby wave source near the entrance of the South Asian jet by the convergence of upper-level divergent wind.

scholarly journals Response of Winter Moisture Circulation to the India–Burma Trough and Its Modulation by the South Asian Waveguide

2017 ◽  
Vol 30 (4) ◽  
pp. 1197-1210 ◽  
Author(s):  
Xiuzhen Li ◽  
Yongqin David Chen ◽  
Wen Zhou
Keyword(s):  
South Asian ◽  
South China ◽  
North Atlantic ◽  
Wave Train ◽  
Phase Speed ◽  
Winter Precipitation ◽  
The South ◽  
The North ◽  
The North Atlantic ◽  
Potential Precursor

Abstract The response of moisture circulation to the daily evolution of the India–Burma Trough (IBT) and the modulation of disturbances along the South Asian waveguide are analyzed to seek a potential precursor of winter precipitation over south China. Daily observational precipitation and reanalysis data from ERA-Interim during 1979–2012 are employed. It is found that moisture circulation in response to the IBT is part of the zonally oriented wave trains along the South Asian waveguide, but it persists longer and migrates farther eastward than other lobes. Cyclonic moisture transport enhances the moisture supply to south China as a strong IBT develops, and shifts eastward abruptly after the peak of IBT with enhanced precipitation shifting from southwest to southeast China. This response is a joint effect of synoptic, intraseasonal, and interannual components that show similar wave train structures, whereas slight differences still occur. The synoptic component shows a shorter wavelength, more southerly path, faster phase speed, and group velocity, with the signal from the North Atlantic to the Bay of Bengal (BoB) in 6 days, implying that a disturbance over the North Atlantic is a potential precursor of winter precipitation over south China. The synoptic moisture convergence is more intensive than that at other scales upstream except over Southeast Asia, where all components are comparable. This might result from the constrained moisture source from BoB at the synoptic scale because of a short wavelength, while widespread sources from BoB–western North Pacific (WNP) at other scales as wavelengths are longer.

Seasonal variation of eddy kinetic energy in the South China Sea

2012 ◽  
Vol 31 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Hui Wang ◽  
Dakui Wang ◽  
Guimei Liu ◽  
Huiding Wu ◽  
Ming Li
Keyword(s):  
Seasonal Variation ◽  
Kinetic Energy ◽  
South China Sea ◽  
South China ◽  
Eddy Kinetic Energy ◽  
The South China Sea ◽  
The South ◽  
China Sea

scholarly journals Eddy-induced Heat Transport in the South China Sea

2021 ◽  
Author(s):  
Ruibin Ding ◽  
Jiliang Xuan ◽  
Tao Zhang ◽  
Lei Zhou ◽  
Feng Zhou ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
South China Sea ◽  
Heat Transport ◽  
South China ◽  
Eddy Kinetic Energy ◽  
The South China Sea ◽  
Kuroshio Intrusion ◽  
The South ◽  
China Sea ◽  
The Kuroshio

AbstractEddy-induced heat transport (EHT) in the South China Sea (SCS) is important for the heat budget. However, knowledge of its variability is limited owing to discrepancies arising from the limitation of the down-gradient method and uncertainties arising from numerical models. Herein, we investigated the spatiotemporal variability and dynamics of EHT using a well-validated assimilated model. In particular, to the southeast of Vietnam (SEV) and west of Luzon Strait (WLS), significant values of annual mean EHT are observed and most EHT is confined in the upper 400 m. EHT also exhibits significant seasonality, and the largest EHT amplitude in autumn at SEV is mainly driven by the wind stress curl, while that in winter at WLS is mainly related to the Kuroshio intrusion. Energy budget analysis reveals that both the barotropic and baroclinic instabilities increase the eddy kinetic energy in autumn at SEV, whereas only the barotropic instability contributes to the eddy kinetic energy at WLS in winter. Specially, an up-gradient EHT is observed at WLS in all four seasons, characterized by the same directions between EHT and mean temperature gradient. The up-gradient EHT at WLS is induced by the baroclinic instability through an inverse energy transfer, which is generated by the interaction between the Kuroshio intrusion and topography below the surface layer. Moreover, the most significant up-gradient EHT in winter shows a wave-like southwestward propagating pattern in the subsurface layer.

Characteristics and Mechanisms of the Subseasonal Eastward Extension of the South Asian High

2015 ◽  
Vol 28 (17) ◽  
pp. 6799-6822 ◽  
Author(s):  
Xuejuan Ren ◽  
Dejian Yang ◽  
Xiu-Qun Yang
Keyword(s):  
South Asian ◽  
Diabatic Heating ◽  
Southern China ◽  
Wave Train ◽  
Northern China ◽  
Western Pacific ◽  
South Asian High ◽  
The South ◽  
Normal Rainfall ◽  
Anomalous Heating

Abstract This study investigates the features of eastward extension of the South Asian high (SAH) and its connection with diabatic heating and rainfall over eastern Asia on subseasonal time scales. The causes of SAH’s eastward extension are examined by potential vorticity (PV) diagnosis with emphasis on the joint role of diabatic heating feedback and midlatitude wave train. The SAH’s eastward extension features eastward propagation of a wave train across Eurasia. Among the wave train, the migration of weak high from the western flank of the Tibetan Plateau (TP) to the east of TP contributes to the SAH’s eastward extension at the early stage. When the SAH approaches its easternmost position, a strong negative PV (positive geopotential height) center prevails to the east of the TP at 200 hPa. The associated anomalies in diabatic heating and rainfall include the anomalous heating and above-normal rainfall over the South China Sea (SCS) and subtropical western Pacific occurring 12 days before the SAH’s easternmost stretch, and then anomalous cooling and below-normal rainfall over the southern foot of the TP and southern China and heating and above-normal rainfall over the northern TP and northern China a week later. The anomalous heating and ascending motion over the northern TP and northern China act to increase negative PV locally at 200 hPa. The cooling and descending induce positive PV over southern China. The north–south dipolar structure of PV anomaly with the climatological northerly flow is favorable to southward advection of a negative PV anomaly at 200 hPa. The anomalous heating over the SCS–western Pacific helps to develop a below-normal rainfall condition over southern China via inducing a lower-level anomalous cyclone over coastal region. These processes are conducive to the SAH’s eastward extension at its later stage.

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