Sishili Bay is the most important aquiculture and tourism area for the city of Yantai, China; however, red tides occurred frequently and have caused huge economic losses in this bay in recent years. To gain a better u...Sishili Bay is the most important aquiculture and tourism area for the city of Yantai, China; however, red tides occurred frequently and have caused huge economic losses in this bay in recent years. To gain a better understanding of the local ecological environments in the bay, we conducted this research between 2003 and 2008 to analyze variations in nutrients and chlorophyll （chl-a） during high frequency red tide period （May to September）. The results show that the chl-a concentration increased from 2.70 in 2003 to 7.26 mg/m3 in 2008, while the concentration of total inorganic nitrogen （TIN） and silicate （SiO3-Si） increased lineally from 5.18 and 1.45 pmol/L in 2003 to 18.57 and 9.52 pmol/L in 2008, respectively, and the annual phosphate （PO4-P） varied between 0.15 and 0.46 μmol/L. Special attention was given to a red tide in August 2007 occurred when water temperature was high and nutrient concentrations increased sharply because of a heavy rainfall. Overall, the results show the P limitation in Sishili Bay, and reveal that red tides were caused by eutrophication from terrestrial inputs and local warm weather, particularly during rainy periods. Therefore, to control red tide, greater efforts should be made to reduce sewage discharges into Sishili Bay, particularly during rainfall seasons.展开更多
A complete set of one-month Acoustic Doppler Profiler (ADP) current data at a station in the southern Yellow Sea (SYS) is analyzed using the rotary spectrum method. The results revealed different rotary properties bet...A complete set of one-month Acoustic Doppler Profiler (ADP) current data at a station in the southern Yellow Sea (SYS) is analyzed using the rotary spectrum method. The results revealed different rotary properties between barotropic and baroclinic tidal currents. The barotropic and baroclinic tidal currents rotate elliptically counter-clockwise and clockwise, respectively. Meanwhile, baroclinic bottom tidal currents are almost along-isobath. The baroclinic cross-isobath velocities attenuate quickly at the bottom, implying important effects of bottom topography on the cross-isobath motions.展开更多
Horizontal winds in the mesosphere （80-100 km） were measured by meteor radar in Wuhan, China （30° N, 114° E） over a 45-month interval in 2002-2005 and the data examined to investigate the monthly mean be...Horizontal winds in the mesosphere （80-100 km） were measured by meteor radar in Wuhan, China （30° N, 114° E） over a 45-month interval in 2002-2005 and the data examined to investigate the monthly mean behavior of the Ol tide. A clear seasonal variation in amplitude of the O1 tide ranging from -0.3 m/s to 2.6 m/s was observed. In most months, the northward and eastward components differed by about 7 lunar hours with the eastward component leading. Comparison of the amplitudes of the M2 and O1 tides suggests the O1 tide is quite stronger over Wuhan, China. The amplitude ratio of the O1 tide to the M2 tide is quite stronger than that the gravitational potential being 0.41. The vertical wavelength of the O1 tide differs on a monthly basis. Height profiles of the O1 tide showed obvious height variation. The O1 tide is stronger in January and July. In different month, the vertical wavelength for the O1 tide changes considerably at the same height. The year＇s variation trend of the northward and eastward components is very similar in both phase and amplitude.展开更多
The propagation and fission process of internal solitary waves （ISWs） with amplitudes of about 170 m are simulated in the northeast of the South China Sea （NSCS） by using the generalized Korteweg-de Vries （KdV） ...The propagation and fission process of internal solitary waves （ISWs） with amplitudes of about 170 m are simulated in the northeast of the South China Sea （NSCS） by using the generalized Korteweg-de Vries （KdV） equation under continuous stratification. More attention is paid to the effects of the ebb and flood background currents on the fission process of ISWs. This kind of background current is provided by the composed results simulated in terms of monthly mean baroclinic circulation and barotropic tidal current. It is found that the obtained relation of the number of fission solitons to the water depth and stratification is roughly in accordance with the fission law derived by Djordjevic and Redekopp in 1978; however, there exists obvious difference between the effects of the ebb and flood background currents on the wave-lengths of fission solitons （defined as the distance between two neighboring peaks of ISWs）. The difference in nonlinearity coefficient a between the ebb and flood background currents is a main cause for the different wave-lengths of fission solitons.展开更多
基金Supported by the CAS/SAFEA International Partnership Program for Creative Research Teams (Nos. KZCX2-YW-T001 and KZCX2-YW- 213)the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-226)the National Natural Science Foundation of China (Nos. 40976091 and 31061160190)
文摘Sishili Bay is the most important aquiculture and tourism area for the city of Yantai, China; however, red tides occurred frequently and have caused huge economic losses in this bay in recent years. To gain a better understanding of the local ecological environments in the bay, we conducted this research between 2003 and 2008 to analyze variations in nutrients and chlorophyll （chl-a） during high frequency red tide period （May to September）. The results show that the chl-a concentration increased from 2.70 in 2003 to 7.26 mg/m3 in 2008, while the concentration of total inorganic nitrogen （TIN） and silicate （SiO3-Si） increased lineally from 5.18 and 1.45 pmol/L in 2003 to 18.57 and 9.52 pmol/L in 2008, respectively, and the annual phosphate （PO4-P） varied between 0.15 and 0.46 μmol/L. Special attention was given to a red tide in August 2007 occurred when water temperature was high and nutrient concentrations increased sharply because of a heavy rainfall. Overall, the results show the P limitation in Sishili Bay, and reveal that red tides were caused by eutrophication from terrestrial inputs and local warm weather, particularly during rainy periods. Therefore, to control red tide, greater efforts should be made to reduce sewage discharges into Sishili Bay, particularly during rainfall seasons.
基金This work is supported by the National Natural Science Foundation of China (No. 40606009)the special Post-doctoral research Foundation of Shandong Province (No. 200602002).
文摘A complete set of one-month Acoustic Doppler Profiler (ADP) current data at a station in the southern Yellow Sea (SYS) is analyzed using the rotary spectrum method. The results revealed different rotary properties between barotropic and baroclinic tidal currents. The barotropic and baroclinic tidal currents rotate elliptically counter-clockwise and clockwise, respectively. Meanwhile, baroclinic bottom tidal currents are almost along-isobath. The baroclinic cross-isobath velocities attenuate quickly at the bottom, implying important effects of bottom topography on the cross-isobath motions.
基金Acknowledgements This research was supported by National Natural Science Foundation of China （41104095）
文摘Horizontal winds in the mesosphere （80-100 km） were measured by meteor radar in Wuhan, China （30° N, 114° E） over a 45-month interval in 2002-2005 and the data examined to investigate the monthly mean behavior of the Ol tide. A clear seasonal variation in amplitude of the O1 tide ranging from -0.3 m/s to 2.6 m/s was observed. In most months, the northward and eastward components differed by about 7 lunar hours with the eastward component leading. Comparison of the amplitudes of the M2 and O1 tides suggests the O1 tide is quite stronger over Wuhan, China. The amplitude ratio of the O1 tide to the M2 tide is quite stronger than that the gravitational potential being 0.41. The vertical wavelength of the O1 tide differs on a monthly basis. Height profiles of the O1 tide showed obvious height variation. The O1 tide is stronger in January and July. In different month, the vertical wavelength for the O1 tide changes considerably at the same height. The year＇s variation trend of the northward and eastward components is very similar in both phase and amplitude.
基金supported by the Key Program of National Natural Science Foundation of China under contract No.41030855
文摘The propagation and fission process of internal solitary waves （ISWs） with amplitudes of about 170 m are simulated in the northeast of the South China Sea （NSCS） by using the generalized Korteweg-de Vries （KdV） equation under continuous stratification. More attention is paid to the effects of the ebb and flood background currents on the fission process of ISWs. This kind of background current is provided by the composed results simulated in terms of monthly mean baroclinic circulation and barotropic tidal current. It is found that the obtained relation of the number of fission solitons to the water depth and stratification is roughly in accordance with the fission law derived by Djordjevic and Redekopp in 1978; however, there exists obvious difference between the effects of the ebb and flood background currents on the wave-lengths of fission solitons （defined as the distance between two neighboring peaks of ISWs）. The difference in nonlinearity coefficient a between the ebb and flood background currents is a main cause for the different wave-lengths of fission solitons.
