Summertime wave height variability along the Pacific and Okhotsk Sea coasts of northern Japan

摘要

Wave height variability along the Pacific and Okhotsk Sea coasts of northern Japan in June August is investigated using in situ measurements and reanalysis data. The coastal wave height is dominated by the persistent easterly winds induced by the developed Okhotsk high. These winds, which can induce cool summers in northern Japan, favor wave development toward the coast of northern Japan. The wave variability is enhanced along the coast of northern Tohoku by the strong local winds occurring in the lee of Cape Erimo. The results for variability of wave height along the Pacific and Okhotsk Sea coasts of northern Japan are supported by composite analysis of reanalysis wave data. When the Okhotsk high develops and the resulting easterly winds are dominant, the wave height increases near the coast of and to the east of northern Japan. Wave height also increases in the Japan Sea and along the southern coast of Japan, whereas wave height decreases in the Okhotsk Sea. These wave height variations reflect the distinct wind fields associated with the developed Okhotsk high. Trends in wave height are examined using the in situ measurements available for over 20 yr. Only the decreasing trends in the south of northern Japan in August are statistically significant.