page_title: Sea of Japan
section_title: Climate
hierarchical_section_title: Sea of Japan / Climate
caption_attribution_description: English: Von Karman vortices off the coast of Rishiri Island in Japan. Français&#160;: Une Allée de tourbillons de Karman sous le vent de l'île Rishiri au Japon. 日本語: 利尻島から風下に伸びるカルマン渦模様の雲. Camera location45°&#160;10′&#160;33.86″&#160;N, 141°&#160;13′&#160;24.89″&#160;E&#160;View this and other nearby images on: OpenStreetMap - Google Earth
context_page_description: The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the Russian mainland. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, it has almost no tides due to its nearly complete enclosure from the Pacific Ocean. This isolation also affects faunal diversity and salinity, both of which are lower than in the open ocean. The sea has no large islands, bays or capes. Its water balance is mostly determined by the inflow and outflow through the straits connecting it to the neighboring seas and the Pacific Ocean. Few rivers discharge into the sea and their total contribution to the water exchange is within 1%.
  The seawater has an elevated concentration of dissolved oxygen that results in high biological productivity. Therefore, fishing is the dominant economic activity in the region. The intensity of shipments across the sea has been moderate owing to political issues, but it is steadily increasing as a result of the growth of East Asian economies.
context_section_description: The sea climate is characterized by warm waters and monsoons. This combination results in strong evaporation, which is especially noticeable between October and March when the strong (12–15 m/s [39–49 ft/s] or higher) north-western monsoon wind brings cold and dry continental air. The evaporation is blown further south causing snowfall in the mountainous western coasts of Japan. This winter monsoon brings typhoons and storms with the waves reaching 8–10 m (26–33 ft) which erode the western coasts of Japan. Tsunami waves were also recorded in the sea. In addition, the monsoon enhances the surface water convection, down to the depths of 30 m (98 ft).
  The coldest months are January and February with the average air temperature of −20 °C (−4 °F) in the north and 5 °C (41 °F) in the south. The northern one-quarter of the sea, particularly the Siberian coast and the Strait of Tartary, freezes for about 4−5 months. The timing and extent of freezing vary from year to year, so ice may start forming in the bays as early as in October and its remains may be seen even in June. Ice cover is continuous only in the bays and forms floating patches in the open sea. Ice melting in spring results in cold currents in the northern areas.
  In summer the wind weakens to 2–7 m/s (6.6–23.0 ft/s) and reverses its direction, blowing warm and humid air from the North Pacific onto the Asian mainland. The warmest month is August with the average air temperature of 15 °C (59 °F) in the north and 25 °C (77 °F) in the south. Annual precipitation increases from 310–500 mm (12–20 in) in the north-west to 1,500–2,000 mm (59–79 in) in the south-east.
  A peculiar turbulent cloud pattern, named von Kármán vortices, is sometimes observed over the Sea of Japan. It requires a stable field of low clouds driven by the wind over a small (isolated) and tall obstacle, and usually forms over small mountainous islands. The Sea of Japan meets these conditions as it has frequent winds and cloudy skies, as well as compact, tall islands such as Rishiri (1,721 m or 5,646 ft), Ulleungdo (984 m or 3,228 ft) and Ōshima (732 m or 2,402 ft).
caption: Von Kármán vortices off the coast of Rishiri Island[28]
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