Using TPI to Map Spatial and Temporal Variations of Significant Coastal Upwelling in the Northern South China Sea

Shi, Weian; Huang, Zhi; Hu, Jianyu

doi:10.3390/rs13061065

Cited by 18 publications

(15 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, the disturbances from oceanic internal forcing factors, such as tidal process [5,11], oceanic mesoscale eddy process [66], sea surface current, deep sea current caused by bottom topography, etc. [67][68][69], should be excluded during these intraseasonal and semi-diurnal variation processes related to LLJ events by using more in-depth observations with numerical simulation experiments. Nevertheless, our findings suggest that the potential modulation of the marine biophysical environment by synoptic-scale LLJs on multiple timescales cannot be ignored.…”

Section: Discussionmentioning

confidence: 99%

Potential Associations between Low-Level Jets and Intraseasonal and Semi-Diurnal Variations in Coastal Chlorophyll—A over the Beibuwan Gulf, South China Sea

et al. 2021

View full text Add to dashboard Cite

Low-level jet (LLJ) significantly affects the synoptic-scale hydrometeorological conditions in the South China Sea, although the impact of LLJs on the marine ecological environment is still unclear. We used multi-satellite observation data and meteorological reanalysis datasets to study the potential impact of LLJs on the marine biophysical environment over the Beibuwan Gulf (BBG) in summer during 2015–2019. In terms of the summer average, the sea surface wind vectors on LLJ days became stronger in the southwesterly direction relative to those on non-LLJ days, resulting in enhanced Ekman pumping (the maximum upwelling exceeds 10 × 10−6 m s−1) in most areas of the BBG, accompanied by stronger photosynthetically active radiation (increased by about 20 μmol m−2 s−1) and less precipitation (decreased by about 3 mm day−1). These LLJ-induced hydrometeorological changes led to an increase of about 0.3 °C in the nearshore sea surface temperature and an increase of 0.1–0.5 mg m−3 (decrease of 0.1–0.3 mg m−3) in the chlorophyll-a (chl-a) concentrations in nearshore (offshore) regions. Intraseasonal and diurnal changes in the incidence and intensity of LLJs potentially resulted in changes in the biophysical ocean environment in nearshore regions on intraseasonal and semi-diurnal timescales. The semi-diurnal peak and amplitude of chl-a concentrations on LLJ days increased with respect to those on non-LLJ days. Relative to the southern BBG, LLJ events exhibit greater impacts on the northern BBG, causing increases of the semi-diurnal peak and amplitude with 1.5 mg m−3 and 0.7 mg m−3, respectively. This work provides scientific evidence for understanding the potential mechanism of synoptic-scale changes in the marine ecological environment in marginal seas with frequent LLJ days.

show abstract

Section: Discussionmentioning

confidence: 99%

Potential Associations between Low-Level Jets and Intraseasonal and Semi-Diurnal Variations in Coastal Chlorophyll—A over the Beibuwan Gulf, South China Sea

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The upwelling phenomenon has also been reported in the eastern coast of Hainan Island, Leizhou Peninsula, and the Pearl River Estuary where mangroves are largely distributed [30,31]. In particular, the sea surface temperature in the east of Guangdong was as low as 22 • C during an upwelling event [32]. The studies of upwelling in these areas mainly focused on nutrient enrichment and phytoplankton and zooplankton changes [27,33,34].…”

Section: Introductionmentioning

confidence: 92%

Physiological and Biochemical Responses of Kandelia obovata to Upwelling Stress

Wang

Dong

et al. 2022

Water

View full text Add to dashboard Cite

Mangroves growing in intertidal areas are faced with various stresses caused by coastal human activities and oceanic and atmospheric sources. Although the study of the physiological and biochemical characteristics of mangroves has been developing over the past four decades, the effect of upwelling on mangroves in plants stress resistance has seldom been investigated. Here, changes in the physiological and biochemical characteristics of the leaves of Kandelia obovata seedlings in response to upwelling were investigated (air temperature: 25 °C; water temperature: control 25 °C, 13 °C, and 5 °C; salinity: 10‰). The results revealed that upwelling treatment caused an increase in chlorophyll content but a decrease in photosynthetic fluorescence parameters. Hydrogen peroxide (H2O2) production and malondialdehyde activity (MDA) increased with the decrease in upwelling temperature. The proline content increased under upwelling stress, whereas the soluble sugar content decreased. Further, the activities of antioxidant enzymes, such as superoxide dismutase activity (SOD) and peroxidase activity (POD), showed an increasing trend during the treatment, while catalase activity (CAT) decreased. It was evidenced that upwelling stress triggered the physiological and biochemical responses of Kandelia obovata seedlings. This effect became more intense as the upwelling temperature decreased, and all these indicators showed different responses to upwelling stress. Through synthesizing more energy and regulating enzyme activity and osmotic pressure, the leaves of K. obovata formed a resistance mechanism to short-term upwelling.

show abstract

“…This approach appears very close to the popular seeded region growing (SRG) image clustering by Adams and Bischof (1994), with two differences that are worth noticing: (a) the criterion involves the within-cluster average temperature rather than the temperature difference as in SRG; (b) main parameters are adjusted automatically according to the least-squares approximation criterion rather than heuristically. Similar constructions involving within-cluster average temperatures are being developed regarding different areas of the ocean in Aouni et al (2021), Houghton and Wilson (2020), Huang and Wang (2019), Shi et al (2021),and Tamim et al (2015.…”

Section: Clustering In the Analysis Of Oceanographic Phenomenamentioning

confidence: 99%

Piece‐wise constant cluster modelling of dynamics of upwelling patterns

Nascimento,

Martins,

Relvas

et al. 2023

Expert Systems

View full text Add to dashboard Cite

A comprehensive approach is presented to analyse season's coastal upwelling represented by weekly sea surface temperature (SST) image grids. Our three‐stage data recovery clustering method assumes that the season's upwelling can be divided into shorter periods of stability, ranges, each to be represented by a constant core and variable shell parts. Corresponding clustering algorithms parameters are automatically derived by using the least‐squares clustering criterion. The approach has been successfully applied to real‐world SST data covering two distinct regions: Portuguese coast and Morocco coast, for 16 years each.

show abstract

Using TPI to Map Spatial and Temporal Variations of Significant Coastal Upwelling in the Northern South China Sea

Cited by 18 publications

References 27 publications

Potential Associations between Low-Level Jets and Intraseasonal and Semi-Diurnal Variations in Coastal Chlorophyll—A over the Beibuwan Gulf, South China Sea

Potential Associations between Low-Level Jets and Intraseasonal and Semi-Diurnal Variations in Coastal Chlorophyll—A over the Beibuwan Gulf, South China Sea

Physiological and Biochemical Responses of Kandelia obovata to Upwelling Stress

Piece‐wise constant cluster modelling of dynamics of upwelling patterns

Contact Info

Product

Resources

About