Studies on the water-mass formation and temperature determination in the Kuroshio and Kuroshio Extension regions

我们利用这笔经费引进了低声多普勒电流分析器（LADCP）。我们开发了一种针对CTD数据的LADCP数据处理算法，其精度可达几厘米/秒。利用该LADCP，我们于1999年7月、1999年8月~ 9月、2000年2月~ 3月、2000年10月~ 11月、2001年1月~ 2月在西北太平洋进行了一系列观测，获得了180多天、450多个站点的LADCP资料。这种密集和广泛的LADCP观测对世界海洋界来说是值得注意的。利用这些LADCP和CTD数据，我们开发了一种估算调整后地转速度和垂直混合系数的分析方法。我们将这些新方法应用于地表和地下循环的量化，从而产生了大量的结果和出版物。提出了一种准地转动力学条件下的垂直速度分析方法，得到了黑潮伸展带沿等轴面和地表-地下相互作用及俯冲方向的大垂直速度分析结果。我们还进行了历史数据分析；20世纪上半叶黑潮延伸区海温的年代际变化与20世纪上半叶一样。结合历史数据和整体混合层模式，阐明了黑潮和黑潮扩展热输送对确定海温的重要性。混合层深度和温度发生了变化，混合层深度的变化比海温的变化早几年。1980年代后期的变化可能是混合层的变化和热输运共同作用的结果。从海洋环流模式来看，黑潮的热输送对温度也起着至关重要的作用。

We introduced Lowered Acoustic Doppler Current Profiler (LADCP) by this grant. We developed a data processing algorithm for LADCP with CTD data that is as accurate as a few cm/sec. With this LADCP, we performed a series of observations in the northwestern Pacific in July 1999, August-September 1999, February-March 2000, October-November 2000, January-February 2001, in which we obtained total observations amounted to be over 180days and over 450 stations of LADCP data in two years. This intensive and extensive LADCP observations are remarkable for the world oceanographic community. Using these LADCP and CTD data, we developed a analysis method for estimating adjusted geostrophic velocity and vertical mixing coefficients. We applied these new methods to quantifying surface and subsurface circulations to produce a large number of results and publications. We developed a analysis method of vertical velocity assuming quasi-geostrophic dynamics, and we obtained results of large vertical velocities along isopycnal surface and surface-subsurface interaction and subduction along the Kuroshio Extension. We also performed historical data analyzes; in early 20th century the interdecadal SST variations occurred in the Kuroshio Extension regions as in late half. With historical data combined with bulk mixed layer models, we clarified the importance of heat transport by the Kuroshio and Kuroshio Extension on the determination of SST. Regime shifts of mixed layer depths and temperature were detected and the change of mixed layer depth a few years preceded the SST shift. The shifts in late 1980s are suggested to be due to the combinations of shifts in mixed layer and heat transport. From oceanic general circulation models, heat transport by the Kuroshio is also suggested to be crucial for temperature.