Vertical Structure of the Southwest Monsoon Low-Level Jet over the Central and Eastern Arabian Sea

1986 ◽  
Vol 43 (24) ◽  
pp. 3266-3272 ◽  
Author(s):  
Robert L. Grossman ◽  
Carl A. Friehe
Keyword(s):  
Arabian Sea ◽  
Vertical Structure ◽  
Southwest Monsoon ◽  
Low Level ◽  
Eastern Arabian Sea ◽  
Low Level Jet

scholarly journals The Moisture Sources and Transport Processes for a Sudden Rainstorm Associated with Double Low-Level Jets in the Northeast Sichuan Basin of China

Atmosphere ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 160 ◽  
Author(s):  
Fangli Zhang ◽  
Guoping Li ◽  
Jun Yue
Keyword(s):  
South China Sea ◽  
South China ◽  
Moisture Transport ◽  
Sichuan Basin ◽  
Arabian Sea ◽  
Low Level ◽  
China Sea ◽  
Northeast Sichuan Basin ◽  
Low Level Jets ◽  
Low Level Jet

A sudden rainstorm that occurred in the northeast Sichuan Basin of China in early May 2017 was associated with a southwest low-level jet (SWLJ) and a mountainous low-level jet (MLLJ). This study investigates the impact of the double low-level jets (LLJs) on rainfall diurnal variation by using the data from ERA5 reanalysis, and explores the characteristics of water vapor transport, including the main paths and sources of moisture, by using the HYSPLIT-driven data of the ERA—interim, GDAS (Global Data Assimilation System), and NCEP/NCAR reanalysis data. The analysis shows that the sudden rainstorm in the mountain terrain was located at the left side of the large-scale SWLJ at 700 hPa, and at the exit region of the meso-scale MLLJ at 850 hPa. The double LLJs provide favorable moisture conditions, and the enhancement (weakening) of the LLJs is ahead of the start (end) of the rainstorm. The capacity of the LLJ at 850 hPa with respect to moisture convergence is superior to that at 700 hPa, especially when the MLLJ and the southerly LLJ at 850 hPa appear at the same time. The HYSPLIT backward trajectory model based on Lagrangian methods has favorable applicability in the event of sudden rainstorms in mountainous terrain, and there is no special path of moisture transport in this precipitation event. The main moisture sources of this process are the East China Sea–South China Sea, the Arabian Sea–Indian Peninsula, the Bay of Bengal, and the Middle East, accounting for 38%, 34%, 17% and 11% of the total moisture transport, respectively. Among them, the moisture transport in the Bay of Bengal and the South China Sea–East China Sea is mainly located in the lower troposphere, which is below 900 hPa, while the moisture transport in the Arabian Sea–Indian Peninsula and the Middle East is mainly in the middle and upper layers of the troposphere. The moisture changes of the transport trajectories are affected by the topography, especially the high mountains around the Sichuan Basin.

Remote influences on the Indian monsoon Low-Level Jet intraseasonal variations

2020 ◽  
Author(s):  
Takeshi Izumo ◽  
Maratt Satheesan Swathi ◽  
Matthieu Lengaigne ◽  
Jérôme Vialard ◽  
Dr Ramesh Kumar
Keyword(s):  
Indian Ocean ◽  
Indian Summer Monsoon ◽  
Arabian Sea ◽  
Large Scale ◽  
Indian Monsoon ◽  
Westerly Wind ◽  
Low Level ◽  
Intraseasonal Variations ◽  
The Indian Ocean ◽  
Low Level Jet

<p>A strong Low-Level Jet (LLJ), also known as the Findlater jet, develops over the Arabian Sea during the Indian summer monsoon. This jet is an essential source of moisture for monsoonal rainfall over the densely-populated Indian subcontinent and is a key contributor to the Indian Ocean oceanic productivity by sustaining the western Arabian Sea upwelling systems. The LLJ intensity fluctuates intraseasonally within the ~20- to 90-day band, in relation with the northward-propagating active and break phases of the Indian summer monsoon. Our observational analyses reveal that these large-scale regional convective perturbations  only explain about half of the intraseasonal LLJ variance, the other half being unrelated to large-scale convective perturbations over the Indian Ocean. We show that convective fluctuations in two regions outside the Indian Ocean can remotely force a LLJ intensification, four days later. Enhanced atmosphericdeep convection over the northwestern tropical Pacific yields westerly wind anomalies that propagate westward to the Arabian Sea as baroclinic atmospheric Rossby Waves. Suppressed convection over the eastern Pacific / North American monsoon region yields westerly wind anomalies that propagate eastward to the Indian Ocean as dry baroclinic equatorial Kelvin waves. Those largely independent remote influences jointly explain ~40% of the intraseasonal LLJ variance that is not related to convective perturbations over the Indian Ocean (i.e. ~20% of the total), with the northwestern Pacific contributing twice as much as the eastern Pacific. Taking into account these two remote influences should thus enhance the ability to predict the LLJ.</p><p> </p><p>Related reference: Swathi M.S, Takeshi Izumo, Matthieu Lengaigne, Jérôme Vialard and M.R. Ramesh Kumar:Remote influences on the Indian monsoon Low-Level Jet intraseasonal variations, accepted in Climate Dynamics.</p>

scholarly journals Tracing the strength of the southwest monsoon using boron isotopes in the eastern Arabian Sea

2015 ◽  
Vol 42 (5) ◽  
pp. 1450-1458 ◽  
Author(s):  
Sushant S. Naik ◽  
P. Divakar Naidu ◽  
Gavin L. Foster ◽  
Miguel A. Martínez‐Botí
Keyword(s):  
Arabian Sea ◽  
Southwest Monsoon ◽  
Boron Isotopes ◽  
Eastern Arabian Sea

Nutrient biogeochemistry of the eastern Arabian Sea during the southwest monsoon retreat

2012 ◽  
Vol 68 (3) ◽  
pp. 703-718 ◽  
Author(s):  
Rejomon George ◽  
K. R. Muraleedharan ◽  
G. D. Martin ◽  
P. Sabu ◽  
Vijay John Gerson ◽  
...  
Keyword(s):  
Arabian Sea ◽  
Southwest Monsoon ◽  
Eastern Arabian Sea

scholarly journals Characterization of Night Low Level Jet (NLLJ) on a global scale

2018 ◽  
Vol 1 (35) ◽  
Author(s):  
Iago Algarra ◽  
Raquel Nieto ◽  
Luis Gimeno
Keyword(s):  
Vertical Profile ◽  
Vertical Structure ◽  
Temporal Evolution ◽  
Global Scale ◽  
Maximum Intensity ◽  
Low Level ◽  
Low Level Jets ◽  
Low Level Jet ◽  
Objective Methodology

The Nocturnal or Night Low-Level Jets (NLLJ) are those jets that have their maximum intensity at night and are formed by the decoupling of the PBL. The aim of this study is the detection of NLLJ using an objective methodology (Rife et al., 2010). To do it, an index based in the vertical structure of the wind’s temporal variation was used. Once identified, we investigated its structure, the vertical profile, and its temporal evolution.

Sign in / Sign up

Export Citation Format

Share Document