In this study,an operational forecasting system of sea dike risk in the southern Zhejiang Province,South China was developed based on a coupled storm-surge and wave model.This forecasting system is important because o...In this study,an operational forecasting system of sea dike risk in the southern Zhejiang Province,South China was developed based on a coupled storm-surge and wave model.This forecasting system is important because of the high cost of storm-surge damage and the need for rapid emergency planning.A comparison with astronomical tides in 2016 and the validation of storm surges and high water marks of 20 typhoons verified that the forecast system has a good simulation ability.The system can forecast relatively realistic water levels and wave heights as shown under the parametric atmospheric forces simulated in a case study;the sea dikes in credible high risk were mainly located in the estuaries,rivers,and around the islands in the southern Zhejiang.Therefore,the forecast system is applicable in the southern Zhejiang with a support to the effective prevention from typhoon storm-surge damage.展开更多
Here,we report the results of high-resolution nitrate measurements using an optical nitrate profiler(in situ ultraviolet spectrophotometer,ISUS)along transect across a high-turbidity shelf(East China Sea)and a low-tur...Here,we report the results of high-resolution nitrate measurements using an optical nitrate profiler(in situ ultraviolet spectrophotometer,ISUS)along transect across a high-turbidity shelf(East China Sea)and a low-turbidity shelf(Chukchi Sea).The ISUS-measured nitrate concentrations closely reproduced the results measured by conventional bottle methods in low-turbidity waters.However,for high-turbidity waters of the East China Sea(salinity<30),a correction factor of 1.19 was required to match the standard bottle measurements.The high-resolution ISUS data revealed subtle spatial variability(e.g.,a subsurface nitrate minimum)that may have been missed if based solely on bottle results.Four main structures of the nitracline on the East China Sea are apparent from the ISUS nitrate profile.High-resolution nitrate data are important for studying nitrate budgets and nutrient dynamics on continental shelves.展开更多
The ocean response to typhoon is usually characterized by a cooling on the sea surface. In August 2012, however, a warming (instead of cooling) event occurs in the Yellow Sea outside Mokpo, South Korea, as the typhoon...The ocean response to typhoon is usually characterized by a cooling on the sea surface. In August 2012, however, a warming (instead of cooling) event occurs in the Yellow Sea outside Mokpo, South Korea, as the typhoon Bolaven (2012) passes. This study gives a brief introduction to this abnormal sea surface warming. It also provides a multiscale energetic diagnosis of the oceanic response to Typhoon Bolaven. We used a recently developed analysis tool named “multiscale window transform” (MWT). Based on the MWT, we also expanded a localized multiscale energy and vorticity analysis (MS-EVA). The fields are reconstructed onto three scale windows: large-scale, abnormal warming-scale, and high frequency tide-scale windows. The results show that the kinetic energy (KE) in the abnormal warming-scale window of the Mokpo area is obviously enhanced during the passage of Bolaven, which can be attributed to three processes: transfer, transport process of KE and wind stress work. At the same time, the large-scale window in the Mokpo area experiences barotropic instabilities with KE transfers from large-scale window to warming-scale window. Besides, the strong wind stress bought by the passage of Bolaven not only inputs a large amount of KE into warming-scale window, but also causes the increase of KE flux convergence.展开更多
Water temperature is one of the most important factors that affect the occurrence of harmful algal blooms(HABs).Characteristics of sea surface temperature(SST)variability related to a Noctiluca scintillans bloom were ...Water temperature is one of the most important factors that affect the occurrence of harmful algal blooms(HABs).Characteristics of sea surface temperature(SST)variability related to a Noctiluca scintillans bloom were analyzed with Himawari-8 data in the Beibu Gulf during mid-February 2021.An SST warming anomaly was found around the bloom area from 10:00 to 19:00 local time,with a peak temperature of 24.3℃at 15:00,which was 2.9℃higher than the surrounding normal sea water.The possible formation mechanism of the HAB-induced SST anomaly was studied in this work by integrating meteorological,ocean dynamics,and ecological processes.During the HAB event,the sea surface was covered by biological mucilage.A model that considered the net heat flux,heat capacity,density of seawater,and temperature variation was established to estimate the thickness changes(ΔH)in the marine heating layer during the HAB event.The model results show that the heating layer thickness of the HAB area(ΔH between 0.76 m and 0.91 m)was smaller than that of the non-HAB area(ΔH>1.19 m).The SST anomaly in this study might be caused by a thinner and warmer marine heating layer that is related to the biological mucilage on the surface of the HAB area.展开更多
基金Supported by the National Key Research and Development Program of China(No.2016YFC1402000)
文摘In this study,an operational forecasting system of sea dike risk in the southern Zhejiang Province,South China was developed based on a coupled storm-surge and wave model.This forecasting system is important because of the high cost of storm-surge damage and the need for rapid emergency planning.A comparison with astronomical tides in 2016 and the validation of storm surges and high water marks of 20 typhoons verified that the forecast system has a good simulation ability.The system can forecast relatively realistic water levels and wave heights as shown under the parametric atmospheric forces simulated in a case study;the sea dikes in credible high risk were mainly located in the estuaries,rivers,and around the islands in the southern Zhejiang.Therefore,the forecast system is applicable in the southern Zhejiang with a support to the effective prevention from typhoon storm-surge damage.
基金The National Key Research and Development Program of China under contract No.2019YFE0120900the Natural Science Foundation of Zhejiang Province under contract No.Y19D060024+1 种基金the National Natural Science Foundation of China under contract Nos U1709202 and 41806228the Project of Long-term Observation and Research Plan in the Changjiang Estuary and Adjacent East China Sea(LORCE).
文摘Here,we report the results of high-resolution nitrate measurements using an optical nitrate profiler(in situ ultraviolet spectrophotometer,ISUS)along transect across a high-turbidity shelf(East China Sea)and a low-turbidity shelf(Chukchi Sea).The ISUS-measured nitrate concentrations closely reproduced the results measured by conventional bottle methods in low-turbidity waters.However,for high-turbidity waters of the East China Sea(salinity<30),a correction factor of 1.19 was required to match the standard bottle measurements.The high-resolution ISUS data revealed subtle spatial variability(e.g.,a subsurface nitrate minimum)that may have been missed if based solely on bottle results.Four main structures of the nitracline on the East China Sea are apparent from the ISUS nitrate profile.High-resolution nitrate data are important for studying nitrate budgets and nutrient dynamics on continental shelves.
文摘The ocean response to typhoon is usually characterized by a cooling on the sea surface. In August 2012, however, a warming (instead of cooling) event occurs in the Yellow Sea outside Mokpo, South Korea, as the typhoon Bolaven (2012) passes. This study gives a brief introduction to this abnormal sea surface warming. It also provides a multiscale energetic diagnosis of the oceanic response to Typhoon Bolaven. We used a recently developed analysis tool named “multiscale window transform” (MWT). Based on the MWT, we also expanded a localized multiscale energy and vorticity analysis (MS-EVA). The fields are reconstructed onto three scale windows: large-scale, abnormal warming-scale, and high frequency tide-scale windows. The results show that the kinetic energy (KE) in the abnormal warming-scale window of the Mokpo area is obviously enhanced during the passage of Bolaven, which can be attributed to three processes: transfer, transport process of KE and wind stress work. At the same time, the large-scale window in the Mokpo area experiences barotropic instabilities with KE transfers from large-scale window to warming-scale window. Besides, the strong wind stress bought by the passage of Bolaven not only inputs a large amount of KE into warming-scale window, but also causes the increase of KE flux convergence.
基金supported by the National Nature Science Foundation of China(No.41576175)the Project of State Key Laboratory of Satellite Ocean Environment Dynamics(No.SOEDZZ2202)the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.311021004).
文摘Water temperature is one of the most important factors that affect the occurrence of harmful algal blooms(HABs).Characteristics of sea surface temperature(SST)variability related to a Noctiluca scintillans bloom were analyzed with Himawari-8 data in the Beibu Gulf during mid-February 2021.An SST warming anomaly was found around the bloom area from 10:00 to 19:00 local time,with a peak temperature of 24.3℃at 15:00,which was 2.9℃higher than the surrounding normal sea water.The possible formation mechanism of the HAB-induced SST anomaly was studied in this work by integrating meteorological,ocean dynamics,and ecological processes.During the HAB event,the sea surface was covered by biological mucilage.A model that considered the net heat flux,heat capacity,density of seawater,and temperature variation was established to estimate the thickness changes(ΔH)in the marine heating layer during the HAB event.The model results show that the heating layer thickness of the HAB area(ΔH between 0.76 m and 0.91 m)was smaller than that of the non-HAB area(ΔH>1.19 m).The SST anomaly in this study might be caused by a thinner and warmer marine heating layer that is related to the biological mucilage on the surface of the HAB area.
