Warm water intrusion from the Kuroshio into the coastal areas south of Japan

Abstract

Sea surface temperature (SST) has been measured in the south of Japan using a thermometer set up in the ferry boat to investigate the characteristics of the warm water intrudes into the coastal areas from the Kuroshio.

Short-term fluctuations south of Japan and their relationship with the Kuroshio path: 8- to 36-day fluctuations

“…There are two peaks in the global spectrum: between 8 and 36 days and between 40 and 80 days. The existence of the two peaks is consistent with the past observations that there are two kinds of short-term fluctuations of periods of about 20 and 50 days (Kasai et al 1993). From Fig.…”

“…Instead, fluctuations of 50-to 70-day periods became dominant. This is consistent with the observation by Kasai et al (1993) in that fluctuations of a 50-day period were dominant only when the Kuroshio took an offshore non-large-meander path.…”

“…In this paper, short-term fluctuation means fluctuations of periods less than 80 days. Past studies have reported the existence of fluctuations of roughly 10-to 30-day period (Taft 1978;Taira and Teramoto 1981;Sugimoto 1987, 1993;Kasai et al 1993;Ramp et al 2008). The fluctuations of this period appear as frontal waves of the Kuroshio.…”

“…Because of the water exchange, the short-term fluctuations affect the supply of nutrients (Kimura et al 1997), primary production (Kimura et al 1997;Ramp et al 2008), and fishery conditions (Kimura and Sugimoto 1987;Kasai et al 2002;Waseda and Mitsudera 2002;Okazaki et al 2003). A fluctuation of a period of around 50-to 70-day, which is another fluctuation, is related to the S-shaped meandering pattern of the Kuroshio around the Izu Ridge (Kasai et al 1993;Mitsudera et al 2006;Takahashi et al 2011).…”

“…Therefore, descriptions of short-term fluctuations in the Kuroshio are intermittent. Satellite data of sea surface temperature (SST) and sea surface heights (SSH), which have good spatial coverage, have been used in studies on short-term fluctuations (Kasai et al 1993;Kimura et al 1997;Takahashi et al 2011Takahashi et al , 2012. Obtaining SST images from satellites, however, is often hampered by clouds.…”