Frontal upwelling is an important phenomenon in summer in the Yellow Sea (YS) and plays an essential role in the distribution of nutrients and biological species. In this paper, a three-dimensional hydrodynamic model is applied to investigate the characteristics and influencing factors of frontal upwelling in the YS. The results show that the strength and distribution of frontal upwelling are largely dependent on the topography and bottom temperature fronts. The frontal upwelling in the YS is stronger and narrower near the eastern coast than near the western coast due to the steeper shelf slope. Moreover, external forcings, such as the meridional wind speed and air temperature in summer and the air temperature in the preceding winter and spring, have certain influences on the strength of frontal upwelling. An increase in air temperature in the previous winter and spring weakens the frontal upwelling in summer; in contrast, an increase in air temperature in summer strengthens the frontal upwelling. When the southerly wind in summer increases, the upwelling intensifies in the western YS and weakens in the eastern YS. The air temperature influences the strength of upwelling by changing the baroclinicity in the frontal region. Furthermore, the meridional wind speed in summer affects frontal upwelling via Ekman pumping. 相似文献
We introduced the Coupled Model Intercomparison Project Phase 6 (CMIP6) Ocean Model Intercomparison Project CORE2-forced (OMIP-1) experiment by using the First Institute of Oceanography Earth System Model version 2.0 (FIO-ESM v2.0), and comprehensively evaluated the simulation results. Unlike other OMIP models, FIO-ESM v2.0 includes a coupled ocean surface wave component model that takes into account non-breaking surface wave-induced vertical mixing in the ocean and effect of surface wave Stokes drift on air-sea momentum and heat fluxes in the climate system. A sub-layer sea surface temperature (SST) diurnal cycle parameterization was also employed to take into account effect of SST diurnal cycle on air-sea heat ?uxes to improve simulations of air-sea interactions. Evaluations show that mean values and long-term trends of significant wave height were adequately reproduced in the FIO-ESM v2.0 OMIP-1 simulations, and there is a reasonable fit between the SST diurnal cycle obtained from in situ observations and that parameterized by FIO-ESM v2.0. Evaluations of model drift, temperature, salinity, mixed layer depth, and the Atlantic Meridional Overturning Circulation show that the model performs well in the FIO-ESM v2.0 OMIP-1 simulation. However, the summer sea ice extent of the Arctic and Antarctic is underestimated. 相似文献
Coastal wetlands are located in the ecotone of interaction between the land surface and sea, and anthropogenic activities extensively interfere with these wetlands through the reclamation of large tidal wetlands and destruction of the function of the ecosystems. In this study, we investigated the dynamic evolutionary characteristics of the Bohai Rim coastal area over the past 40 years using the Modified Normalized Difference Water Index, the fractal dimension, object-oriented classification, the land-use transfer trajectory, and regression analysis. Additionally, we quantified and monitored the evolution of reclamation and analyzed the correlation between reclamation and coastal wetlands based on 99 Landsat-2, -5, and -8 images (at 60 m and 30 m spatial resolution) over the period 1980–2019. The results are as follows. (1) The coastline of the Bohai Rim increased by 1 631.2 km from 1980 to 2019 with a zigzag variation. The artificial coastline increased by 2 946.1 km, whereas the natural coastline decreased by 90%. (2) The area of man-made wetlands increased by 3 736.9 km2, the area of construction land increased by 1 008.4 km2, and the natural wetland area decreased by 66%. The decrease of tidal flats is the main contributor to the decrease of natural wetland area (takes account for 91.1%). Coastal areas are affected by intense human disturbance, which was taken place across a large area of tidal flats and caused the landscape to fragment and be more heterogeneous. The coastal zone development activities were primarily concentrated in the southern Laizhou Bay, the Yellow River Delta, the Bohai Bay, the northern Liaodong Bay, and the Pulandian Bay. The solidified shorelines and increase in sea level have resulted in intertidal wetlands decreasing and impaired wetland ecology. (3) There is a good agreement between reclamation and the size of the coastal wetlands. Both land reclamation and the reduction in coastal wetland areas are significantly related to the population size, fishery output value, and urbanization rate. In summary, human activities, such as the construction of aquaculture ponds and salt pans, industrialization, and urbanization, are the primary forces that influence the environmental changes in the coastal region. This study is beneficial for establishing and improving the systems for the rational development and utilization of natural resources, and provides theoretical references for restoring wetland ecology and managing future reclamation activities in other coastal zone-related areas. 相似文献
In the northwestern North Pacific, annual net air-sea CO2 flux is greatest in the Kuroshio Extension(KE) zone,owing to its low annual mean partial pressure of CO2(pCO2), and it decreases southward across the basin. To quantify the influences of factors controlling the latitudinal gradient in CO2 uptake, sea surface pCO2 and related parameters were investigated in late spring of 2018 in a study spanning the KE, Kuroshio Recirculation(KR), and... 相似文献
The Mindanao Current (MC) bridges the North Pacific low-latitude western boundary current system region and the Indonesian Seas by supplying the North Pacific waters to the Indonesian Throughflow. Although the previous study speculated that the diapycnal mixing along the MC might be strong on the basis of the water mass analysis of the gridded climatologic dataset, the real spatial distribution of diapycnal mixing along the MC has remained to be clarified. We tackle this question here by applying a finescale parameterization to temperature and salinity profiles obtained using two rapid-sampling profiling Argo floats that drifted along the MC. The western boundary (WB) region close to the Mindanao Islands and the Sangihe Strait are the two mixing hotspots along the MC, with energy dissipation rate ε and diapycnal diffusivity Kρ enhanced up to?~?10–6 W kg?1 and?~?10–3 m2 s?1, respectively. Except for the above two mixing hotspots, the turbulent mixing along the MC is mostly weak, with ε and Kρ to be 10–11–10–9 W kg?1 and 10–6–10–5 m2 s?1, respectively. Strong mixing in the Sangihe Strait can be basically attributed to the existence of internal tides, whereas strong mixing in the WB region suggests the existence of internal lee waves. We also find that water mass transformation along the MC mainly occurs in the Sangihe Strait where the water masses are subjected to strong turbulent mixing during a long residence time.