| The article focuses on the study of climate warming impact of offshore wind field in Jiangsu surface sea level change. Using the Aviso altimetry sea level anomaly (SLA) data and tide gauge data, to analyze the spatial and temporal distribution of Jiangsu sea sea-level change between1993year and2012year. The atmosphere and ocean surface offshore environmental change in the global warming. We analyze the relationship between sea-level changes in Jiangsu offshore and the wind field, the flow field, the sea surface temperature field, and investigate the role of impact factor on Jiangsu coastal sea level change; In the background of climate warming, the last10years of severe gale process compared with the previous10years in the process, extreme intensity increases. Therefore, use the offshore ocean model FVCOM to simulate the strong winds process, including the impact of the typhoon winds and cold windy waters on sea level change in Jiangsu, reveal the role of local wind field and marine elements in the area on sea-level changes. The main conclusions are as follows:There is an obvious season change of the Jiangsu coastal sea level in the1993-2012and was a significant upward trend, rising rate of2.9mm/year. And in coastal the maximum rate of rise up to llmm/yr. The presence of significant seasonal changes in sea level features, summer and winter sea-level trends in the distribution of basic contrary. Sea level has significant regional features in the spatial distribution. EOF analysis showed:the front two modes of Jiangsu coastal sea are season modes and cumulative variance is55%. From the first mode can be seen in the Jiangsu coastal sea level showed a clear upward trend from north to south in general, the most obvious upward trend in the Yellow Sea (from Longkou to Tanxu) and Lianyungang areas Judging from the time factor, the spectrum of the first mode analysis shows the maximum peak is12months, corresponding to the annual cycle. The second mode of the analysis, sea-level changes in Jiangsu Province is mainly seasonal variation.Use the high-resolution reanalysis data (CFSR), the main influencing factors of the SLA within seasonal variation are discussed. Among the various factors affecting, the wind stress at the sea surface wind field generated by forcing compatible with the shoreline of Jiangsu coastal sea level rise, reducing fluctuations play an important role. Due to the impact of global warming after2000, especially in the eastern Jiangsu coastal waters of China over the winter and summer monsoons weakened, so Jiangsu offshore wind stress at the sea surface in winter and summer with the weakening of the sea surface temperature increased significantly. In northerly winds weakened weather during relative sea-level increases in Jiangsu coastal waters.In the context of climate warming, the impact of typhoons and cold on Jiangsu and other weather disasters intensity increased, the rising sea disaster response windy conditions directly affect the economic development along the coast. In this paper, the strong winds typical screening process, combined with regional ocean model FVCOM, systematic process to understand the impact on the regional effects of strong winds temporal evolution of oceanic elements. Simulation results show that:Typhoon "Meihua" and "Milei" twice northward typhoon process, Jiangsu coastal sea levels affect similar cases,"Plum Blossom" will bring strong winds stronger than "Milei", the impact on coastal areas in Jiangsu more serious. Under the influence northward typhoon plum, water Lianyungang and Lusi station presents an obvious increase in the process, the water level of up to0.45meters. In the typhoon landed the role of David, the Lianyungang Lusi station level and volatility declined. Under the influence of December20,2008Middle cold, the remainder flows along the main coastal Jiangsu southward movement, the role of mass transport water to the right Ekman deflected radiation Jiangsu sandbar ridge area, the largest increase in the water level of more than0.4m; in cold process November20,2012, the entire area of the main sea Jiangsu offshore flow, nearshore water level decreased, showing the distribution from west to east.Comparative analysis of typhoon winds and cold impact Jiangsu coastal sea level, the water level in the early typhoon "Meihua" Joan Harbor area is low, the water level in the open sea is about0.25m, with typhoons north, a ridge along the sandbar radiation level rises to a maximum reach about lm, the water level gradient decreased from inshore sea; while under the influence of December20,2008cold wave, the water level in the coastal areas, such as Hong Kong and Hainan higher, reaching a maximum value of about1.5m, the lower level areas far from the sea. Typhoon "Plum", the water level in Jiangsu offshore mainly south than in the north of the situation, and during the cold wind, the water level in Jiangsu offshore contrast, showed a high state north to south, which affect the coastal areas of Jiangsu gale wind there are significant relationship.During typhoons and cold winds, ocean appear respectively in Jiangsu coastal cyclonic vortex and anti-cyclonic vortex, Jiangsu coastal sea levels were lower impact on the concave and convex. Positive vortex center, the lowest sea level; negative vortex in the center of the highest sea level, two types of vortices in the side of the rapids, the water level gradient is large. The relatively cold water and typhoons caused vortex kinetic energy and momentum downstream, both in depth and intensity, hydrodynamic vortex caused by cold wave kinetic energy and momentum spread down over the role of hydrodynamic vortex caused by typhoons more quickly, the amount of value is greater. This is due to cold winds bring cool, cold sea surface caused by rapid cooling, cold under warm unstable vertical stratification on SST, and surface wind stress offshore wind power caused by mixing together, the strength of energy and momentum, the next pass quickly; while typhoon process because of the small temperature difference, mainly wind stress, so the energy and momentum is relatively weak, download speed is slow, shallow depth. |
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