沿海水位和大尺度气候状态——降尺度技术在日本列岛的应用

COAST SEA LEVEL AND THE LARGE-SCALE CLIMATE STATE:A DOWNSCALING EXERCISE FOR THE JAPANESE ISLANDS

1.水位和气候变化 在气候变化特征的争论之中,绝大多数专家认为作为少有的气候参数之一的沿海水位确实在上升。现在科学界已普遍接受由于大气中温室气体的增加引起了地球表面温度的升高,进而通过海水的热膨胀过程导致水位上升的观点(Warrick and Oerlemans,1990)。使用精心研制的综合海洋环流模式输出的数据,已经得到了全球水位上升的空间分布,这些输出的数据有的来自海气耦合模式(Cubasch et al.,1992)。

A major problem envisaged in the course of man-made climate change is sea-level rise. The global aspect of the thermal expansion of seawater is reasonably well simulated by present day climate models; the coastal aspects of sea level rise, com prise the regional response to regional atmospheric forcing and to the large-scale oceanic circulation, is not adequately simulated by a global climate model because of insufficient spacial resolution. A method to infer the coastal aspects of sea level change uses a statistical "downscaling" strategy: a linear statistical modeles built upon a multy-year data set of local sea level data and of large-scale oceanic and/or atmopheric data such as sea-surface temperature or sea-level air-pressure.We apply this idea to the sea level along the Japanese coast. The sea level is 時elated to regional and North Pacific sea-surface temperature and sea-level air pressure. Two relevent processes are identified. One process is the local wind set-up of water due to regional low-frequency wind anomalies; the other is a planetary scale atmosphere-ocean interaction which takes place in the eastern North Pacific.