scholarly journals Satellites HY-1C and Landsat 8 Combined to Observe the Influence of Bridge on Sea Surface Temperature and Suspended Sediment Concentration in Hangzhou Bay, China

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2595
Author(s):  
Shuyi Huang ◽  
Jianqiang Liu ◽  
Lina Cai ◽  
Minrui Zhou ◽  
Juan Bu ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Suspended Sediment Concentration ◽  
Cold Water ◽  
Sediment Concentration ◽  
Sea Surface ◽  
Hangzhou Bay ◽  
Wake Vortex ◽  
Current Flows ◽  
Bottom Cold Water

We analyzed the influence of a cross-sea bridge on the sea surface temperature (SST) and suspended sediment concentration (SSC) of Hangzhou Bay based on landsat8_TIRS data and HY-1C data using an improved single window algorithm to retrieve the SST and an empirical formula to retrieve the SSC. In total, 375 paired sampling points and 70 transects were taken to compare the SST upstream and downstream of the bridge, and nine transects were taken to compare the SSC. The results show the following. (i) In summer, when the current flows through the bridge pier, the downstream SST of the bridge decreases significantly, with a range of 3.5%; in winter, generally, the downstream SST decreases but does not change as obviously as in summer. The downstream SSC increases obviously. (ii) The range of influence of the bridge pier on the downstream SST is about 0.3–4.0 km in width from the bridge and that on the downstream SSC is approximately 0.3–6.0 km. (iii) When the current flows around the pier, a portion of the flow is dispersed in upward and downward directions; the downward flow generates local scour. When the scouring at the front end of the pier stops, the upward flow behind the pier brings the sediment and the bottom cold water downstream, causing the downstream SST to decrease and the SSC to increase. (iv) The other portion passes around the pier, which generates a wake vortex. Once a wake vortex is released, a low-pressure center appears, sucking the sediment and the bottom cold water to the downstream sea surface, reducing the downstream SST and raising the SSC. (v) The range of reduction of the SST downstream of the bridge is shorter than the range of increase in the SSC. This is because the wake vortices have an effect in the 0.3–4.0 km downstream but not in the 4.0–6.0 km. Therefore, the SST and SSC are affected within the range of 0.3–4.0 km by wake vortices, while in the 4.0–6.0 km region, the SSC is still high due to the transport of sediment by currents.

scholarly journals Impact of Changjiang River Discharge on Sea Surface Temperature in the East China Sea

2016 ◽  
Vol 46 (6) ◽  
pp. 1735-1750 ◽  
Author(s):  
Shin’ichiro Kako ◽  
Tomofumi Nakagawa ◽  
Katsumi Takayama ◽  
Naoki Hirose ◽  
Atsuhiko Isobe
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
East China Sea ◽  
River Discharge ◽  
Water Mass ◽  
Cold Water ◽  
Sea Surface ◽  
Changjiang River ◽  
The East China Sea ◽  
Chinese Coast

AbstractThis study investigated how the Changjiang River discharge (CRD) emptying into the East China Sea (ECS) affects the upper-ocean stratification [hence, sea surface temperature (SST) changes], based on ocean general circulation modeling with and without CRD. A new finding in this study is that CRD contributes significantly to a reduction in summer SST in the ECS. Comparison between the two model runs revealed that vertical one-dimensional processes contribute considerably to SST warming in the ECS, while horizontal advection plays an important role in lowering SST in summer. The results of a particle-tracking experiment suggested that the cold water mass formed along the Chinese coast during the previous winter contributes to the SST reduction in the following summer. From the end of the summer monsoon season, the less saline CRD advected toward the Chinese coast generates a shallow mixed layer (ML), which inhibits heat exchange between the ML and thermocline. In winter, heat loss of the ML through the sea surface results in a reduction in SST over a broad region. Water exchange through the bottom of the ML is relatively suppressed by robust stratification, which prevents cooling of the thermocline and leads to a temperature inversion. The northeastward ocean current associated with the summer monsoon carries the cold water mass in the ML across the ECS; therefore, SST decreases during the following season. These results suggest that CRD has a critical role on both the ocean circulation system and the coupled air–sea interactions in the ECS.

scholarly journals A global review of green turtle diet: sea surface temperature as a potential driver of omnivory levels

2020 ◽  
Vol 167 (12) ◽  
Author(s):  
Nicole Esteban ◽  
Jeanne A. Mortimer ◽  
Holly J. Stokes ◽  
Jacques-Olivier Laloë ◽  
Richard K. F. Unsworth ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Satellite Data ◽  
Green Turtle ◽  
Cold Water ◽  
Chelonia Mydas ◽  
Sea Surface ◽  
Terrestrial Plants ◽  
Site Specific ◽  
Quantitative Evidence

AbstractTo better understand dietary requirements, trophic shifts, and trophic interactions of the threatened green turtle (Chelonia mydas), we conducted a comprehensive global review and literature tabulation (177 studies) reporting diets of individuals > 25 cm carapace length. We analysed those studies involving natural sites and healthy animals that reported relative proportions of all diet components (67 studies, 89 datasets at 75 sites, 13 geographic sub-regions, 3 oceans). We compared diets by sub-region and foraging site relative to four diet components, i.e., seagrass, macroalgae, terrestrial plants (including mangroves) and animal matter. To assess sea surface temperature (SST) as an environmental driver, values were extracted from satellite data (single year) and site-specific observations (study durations) and examined relative to diet composition. Satellite data indicated that at warmer sites with temperatures > 25 °C (≥ 6 months annually), diet was predominantly herbivorous (mean = 92.97%; SE = 9.85; n = 69 datasets). At higher latitude sites and in cold-water currents with SST < 20 °C (≥ 6 months annually), dietary animal matter featured prominently (mean = 51.47%; SE = 4.84; n = 20 datasets). Site-specific observations indicated that SST had a small but significant effect on contributions of animal matter (r2 = 0.17, P =  < 0.001) and seagrass (r2 = 0.24, P =  < 0.001) but not macroalgae and terrestrial plants. Our study presents the first quantitative evidence at a global scale that temperature may be an important driver of omnivory, providing a new perspective on variations in green turtle diet, especially in light of global warming and climate change.

scholarly journals Field Investigations of Coastal Sea Surface Temperature Drop after Typhoon Passages

2018 ◽  
Author(s):  
Dong-Jiing Doong ◽  
Jen-Ping Peng ◽  
Alexander V. Babanin
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Coastal Upwelling ◽  
Cold Water ◽  
Temperature Drop ◽  
Open Ocean ◽  
Sea Surface ◽  
Sst Variability ◽  
The Mean ◽  
The Kuroshio

Abstract. Sea surface temperature (SST) variability affects marine ecosystems, fisheries, ocean primary productivity, and human activities and is the primary influence on typhoon intensity. SST drops of a few degrees in the open ocean after typhoon passages have been widely documented; however, few studies have focused on coastal SST variability. The purpose of this study is to determine typhoon-induced SST drops in the near-coastal area (within 1 km of the coast) and understand the possible mechanism. The results of this study were based on extensive field data analysis. Significant SST drop phenomena were observed at the Longdong buoy in northeastern Taiwan during 43 typhoons over the past 20 years (1998~2017). The mean SST drop (∆SST) after a typhoon passage was 6.1 °C, and the maximum drop was 12.5 °C (Typhoon Fungwong in 2008). The magnitude of SST drop was larger than most of the observations in the open ocean. The mean duration of SST drop was 24 hours, and on average, 26.1 hours were required for the SST to recover to the original temperature. The coastal SST drops at Longdong were correlated with the moving tracks of typhoons. When a typhoon passes south of Longdong, the strong and persistent longshore winds induce coastal upwelling and pump cold water up to the surface, which is the dominant cause of SST drops along the coast. In this study, it was determined that cold water mainly intruded from the Kuroshio subsurface in the Okinawa Trough, which is approximately 50 km from the observation site. The magnitude of coastal SST drops depends on the area of overlap between typhoons generating strong winds and the Kuroshio. The dataset used in this study can be accessed by https://doi.pangaea.de/10.1594/PANGAEA.895002.

scholarly journals Measurements of the Radiation Temperature of Antarctic Icebergs and the Surrounding Surface Water

1980 ◽  
Vol 1 ◽  
pp. 19-22 ◽  
Author(s):  
A. Foldvik ◽  
T. Gammelsrød ◽  
Y. Gjessing
Keyword(s):  
Surface Water ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Cold Water ◽  
Radiation Thermometer ◽  
Sea Surface ◽  
Radiation Temperature ◽  
Local Minima ◽  
Individual Variations ◽  
Antarctic Research

During the Norwegian Antarctic Research Expedition 1978–79, temperature measurements of a number of icebergs and the surrounding surface water were made, using an airborne precision radiation thermometer. All icebergs were embedded in cold water-masses with temperatures generally below 0°C and thus the observed temperature anomalies were relatively small, ΔT ≈ 1 deg. Examples of the influence of icebergs on the sea surface temperature including a possible example of upwelling will be shown. The temperature of the snow-covered iceberg surface was almost constant with individual variations ΔT ≈ 0.2 deg. Local minima indicative of snow-covered crevasses were observed.

scholarly journals Field investigations of coastal sea surface temperature drop after typhoon passages

2019 ◽  
Vol 11 (1) ◽  
pp. 323-340 ◽  
Author(s):  
Dong-Jiing Doong ◽  
Jen-Ping Peng ◽  
Alexander V. Babanin
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Coastal Upwelling ◽  
Cold Water ◽  
Temperature Drop ◽  
Open Ocean ◽  
Sea Surface ◽  
Sst Variability ◽  
The Mean ◽  
The Kuroshio

Abstract. Sea surface temperature (SST) variability affects marine ecosystems, fisheries, ocean primary productivity and human activities and is the primary influence on typhoon intensity. SST drops of a few degrees in the open ocean after typhoon passages have been widely documented; however, few studies have focused on coastal SST variability. The purpose of this study is to determine typhoon-induced SST drops in the near-coastal area (within 1 km of the coast) and understand the possible mechanism. The results of this study were based on extensive field data analysis. Significant SST drop phenomena were observed at the Longdong Buoy in northeastern Taiwan during 43 typhoons over the past 20 years (1998–2017). The mean SST drop (ΔSST) after a typhoon passage was 6.1 ∘C, and the maximum drop was 12.5 ∘C (Typhoon Fungwong in 2008). The magnitude of the SST drop was larger than most of the observations in the open ocean. The mean duration of the SST drop was 24 h, and on average, 26.1 h were required for the SST to recover to the original temperature. The coastal SST drops at Longdong were correlated with the moving tracks of typhoons. When a typhoon passes south of Longdong, the strong and persistent longshore winds induce coastal upwelling and pump cold water up to the surface, which is the dominant cause of the SST drops along the coast. In this study, it was determined that cold water mainly intruded from the Kuroshio subsurface into the Okinawa Trough, which is approximately 50 km from the observation site. The magnitude of coastal SST drops depends on the area of overlap between typhoons generating strong winds and the Kuroshio. The dataset used in this study can be accessed from https://doi.org/10.1594/PANGAEA.895002.

Holocene sea surface temperature variations recorded in corals from Kikai Island, Japan

2017 ◽  
Vol 51 (4) ◽  
pp. e9-e14 ◽  
Author(s):  
Hiroto Kajita ◽  
Atsuko Yamazaki ◽  
Takaaki Watanabe ◽  
Chung-Che Wu ◽  
Chuan-Chou Shen ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Sea Surface ◽  
Temperature Variations
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