Improving the Real-time Marine Forecasting of the Northern South China Sea by Assimilation of Glider-observed T/S Profiles

AbstractPrediction of marine conditions is notoriously challenging in the northern South China Sea (NSCS) due to inadequate observations in the region. The underwater gliders that were developed during the past decade may provide observing platforms that could produce required observations. During a field experiment, temperature/salinity (T/S) profiles from a set of underwater gliders were assimilated into a real-time marine forecasting system, along with the assimilation of climatological monthly mean Argo data to constrain the basin-wide model biases. The results show that, in addition to the reduction of the basin-wide model biases by the assimilation of the climatological monthly mean Argo data, the assimilation of glider-observed T/S profiles is efficient to reduce the local biases of the NSCS marine forecasting by as much as 28–31% (19–36%) in 24 h to 120 h forecasts for temperature (salinity) from sea surface to a depth of 1000 m. Our results imply that the real-time marine forecasting for the NSCS can largely benefit from a sustainable glider observing network of the NSCS in the future.

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Three-dimensional regional oceanic element field reconstruction with multiple underwater gliders in the Northern South China Sea

Applied Ocean Research ◽

10.1016/j.apor.2020.102405 ◽

2020 ◽

Vol 105 ◽

pp. 102405

Author(s):

Runfeng Zhang ◽

Shaoqiong Yang ◽

Yanhui Wang ◽

Shuxin Wang ◽

Zhongke Gao ◽

...

Keyword(s):

South China Sea ◽

South China ◽

Northern South China Sea ◽

Three Dimensional ◽

Field Reconstruction ◽

China Sea ◽

Underwater Gliders

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A Real-Time Regional Forecasting System Established for the South China Sea and Its Performance in the Track Forecasts of Tropical Cyclones during 2011–13

Weather and Forecasting ◽

10.1175/waf-d-14-00070.1 ◽

2015 ◽

Vol 30 (2) ◽

pp. 471-485 ◽

Cited By ~ 6

Author(s):

Shiqiu Peng ◽

Yineng Li ◽

Xiangqian Gu ◽

Shumin Chen ◽

Dongxiao Wang ◽

...

Keyword(s):

South China Sea ◽

Real Time ◽

Tropical Cyclones ◽

South China ◽

Dynamical Downscaling ◽

The South China Sea ◽

The South ◽

China Sea ◽

Forecasting System ◽

Atmosphere Model

Abstract A real-time regional forecasting system for the South China Sea (SCS), called the Experimental Platform of Marine Environment Forecasting (EPMEF), is introduced in this paper. EPMEF consists of a regional atmosphere model, a regional ocean model, and a wave model, and performs a real-time run four times a day. Output from the Global Forecast System (GFS) from the National Centers for Environmental Prediction (NCEP) is used as the initial and boundary conditions of two nested domains of the atmosphere model, which can exert a constraint on the development of small- and mesoscale atmospheric perturbations through dynamical downscaling. The forecasted winds at 10-m height from the atmosphere model are used to drive the ocean and wave models. As an initial evaluation, a census on the track predictions of 44 tropical cyclones (TCs) during 2011–13 indicates that the performance of EPMEF is very encouraging and comparable to those of other official agencies worldwide. In particular, EPMEF successfully predicted several abnormal typhoon tracks including the sharp recurving of Megi (2010) and the looping of Roke (2011). Further analysis reveals that the dynamically downscaled GFS forecasts from the most updated forecast cycle and the optimal combination of different microphysics and PBL schemes primarily contribute to the good performance of EPMEF in TC track forecasting. EPMEF, established primarily for research purposes with the potential to be implemented into operations, provides valuable information not only to the operational forecasters of local marine/meteorological agencies or international TC forecast centers, but also to other stakeholders such as the fishing industry and insurance companies.

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The Seasonal Variation of the Anomalously High Salinity at Subsurface Salinity Maximum in Northern South China Sea from Argo Data

Journal of Marine Science and Engineering ◽

10.3390/jmse9020227 ◽

2021 ◽

Vol 9 (2) ◽

pp. 227

Author(s):

Hui Shen ◽

Li Li ◽

Jianlong Li ◽

Zhiguo He ◽

Yuezhang Xia

Keyword(s):

Seasonal Variation ◽

South China Sea ◽

South China ◽

High Salinity ◽

Sea Water ◽

Northern South China Sea ◽

Kuroshio Intrusion ◽

Argo Data ◽

China Sea ◽

The Kuroshio

The large variations in salinity at the salinity maximum in the northern South China Sea (NSCS), as an indicator for the changes in the Kuroshio intrusion (KI), play an important role in the hydrological cycle. The high salinity here is more than 34.65 at the salinity maximum and is intriguing. In the past, the salinity was difficult to trace in the entire NSCS over long periods due to a lack of high-quality observations. However, due to the availability of accumulated temperature and salinity (T-S) profiles from the Argo program, it is now possible to capture subsurface-maximum data on a large spatiotemporal scale. In this study, the salinity maximum distributed in the subsurface of 80 to 200 m at a density of 23.0–25.5 σθ was extracted from decades of Argo data (on the different pressure surfaces, 2006–2019). We then further studied the spatial distribution and seasonal variation of the salinity maximum and its anomalously high salinity. The results suggest that a high salinity (salinity > 34.65, most of which is located at the shallow depths < 100 m) at the subsurface salinity-maximum layer often occurs in the NSCS, especially near the Luzon Strait, which accounts for about 23% of the total salinity maximum. In winter, the anomalously high salinity at the shallow subsurface salinity maximum can extend to the south of 17° N, while it rarely reaches 18° N and tends to locate at deeper waters in summer. The T-S values of the anomalously high-salinity water are between the mean T-S values in the NSCS and north Pacific subsurface water, implying that the outer sea water gradually mixes with the South China Sea water after passing through the Luzon Strait. Finally, our results show that the factors play an important role in the appearance and distribution of the anomalously high salinity at the subsurface salinity maximum, including the strength of the Kuroshio intrusion, the local wind stress curl and the anticyclonic eddy shedding from the loop current.

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