Oceanic condition

The state of the ocean, combining various phenomena such as waves, ocean currents, water temperature, salinity, nutrients, transparency, and the distribution of plankton. Also called sea conditions, this roughly corresponds to the word "tide" used by fishermen. It is a term that corresponds to "weather" in the case of the atmosphere. Sea conditions are determined by meteorological factors as well as marine factors such as water temperature, salinity, and ocean currents. Sea conditions not only affect the effective use of fishery resources and the economic and safe operation of ships, but are also a factor in global climate change and are related to meteorological phenomena such as local weather, weather, and the occurrence of sea fog.

Although ocean conditions are thus closely related to human social and economic activities, no country is fully equipped to grasp them. For this reason, the World Meteorological Organization (WMO), a specialized agency of the United Nations, and the Intergovernmental Oceanographic Commission (IOC) of UNESCO are promoting a plan to exchange observation data on the temperature, currents, and salinity of the ocean surface and near-surface layers in real time, worldwide, in the same way as meteorological observation data, and to swiftly compile and publish information on sea surface temperatures, ocean currents, etc. In Japan, the Japan Meteorological Agency is taking the lead in real time collection and international exchange of ocean observation data, as well as compiling and publishing information on sea surface temperatures, surface water temperatures, and ocean currents, mainly for the northwest Pacific Ocean.

[Kouichi Nagasaka and Takashi Yoshida]

Teramoto Toshihiko et al., eds., Lectures on Oceanography, all 15 volumes (1972-1976, University of Tokyo Press) ▽ Tomoda Yoshifumi and Takano Kenzo, Lectures on Earth Sciences 4: Ocean (1983, Kyoritsu Shuppan) ▽ Unoki Sanae and Kubota Masahisa, The Science of Ocean Waves and Currents (1996, Tokai University Press) ▽ Gamo Toshitaka, The Science of the Oceans: Exploring the Deep Seafloor (1996, Japan Broadcasting Corporation) ▽ Ikeda Hachiro, The World's Oceans and Fisheries Resources: Oceans, Atmosphere, and Fish (1998, Seizando Shoten) ▽ Kumazawa Gen'emon, New Ocean Science, revised edition (1999, Seizando Shoten) ▽ Yanagi Tetsuo, The Science of the Oceans: An Introduction to Oceanography, 2nd edition (2001, Koseisha Koseikaku) ▽ "The Ocean and the Environment - When the Ocean Changes, the Earth Changes" edited by the Oceanographic Society of Japan (2001, Kodansha)" ▽ "The World and Japan Surrounding the Oceans" by Murata Ryohei (2001, Seizando Bookstore)" ▽ "The Use of Deep Ocean Water - A Recyclable Resource for the 21st Century" by Nakajima Toshimitsu (2002, Midori Shobo)" ▽ "The ABCs of Marine Meteorology" by Fukutani Tsuneo, 4th edition (2002, Seizando Bookstore)" ▽ "Lectures on Marine Meteorology" by Fukuchi Akira, 9th edition (2003, Seizando Bookstore)" ▽ "Revised Edition: From Space to the Deep Seafloor - An Illustrated Introduction to the Ocean" edited by Toyoda Keisei, Faculty of Oceanography, Tokai University (2003, Kodansha)" ▽ "An Introduction to Ocean Physics" by Sekine Yoshihiko, 4th edition (2003, Seizando Bookstore)" ▽ "The Ocean" by Uda Michitaka (Iwanami Shinsho)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

波浪、海流、水温、塩分、栄養塩、透明度、プランクトン等の分布などの諸現象を総合した海洋の状態。海象(かいしょう)ともいい、漁業者の用いる「潮(しお)」ということばがほぼこれにあたる。大気の場合の「気象」に対応する用語である。海況を左右するのは、気象の諸要素のほか、水温、塩分、海流などの海洋の諸要素である。海況は水産資源の有効利用や、船舶の経済・安全運航に影響を及ぼすだけでなく、全地球的な気候変動の要因となり、また、局地的な天候や天気、海霧の発生などの気象現象に関連している。

　海況はこのように人間の社会的・経済的活動に密接な関係があるのにもかかわらず、その把握態勢は各国とも十分とはいえない。このため国連の専門機構である世界気象機関（WMO）と、ユネスコの政府間海洋学委員会（IOC）では、海面や海面付近の表層部の水温・海流・塩分の観測データを、気象観測データと同じように、全世界的、即時的に相互交換し、海面水温、海流等の情報を迅速に作成して公表するための計画を推進している。日本では気象庁が中心となって、海洋観測データの即時収集、国際交換を行うとともに、北西太平洋を中心とした海面水温・表層水温・海流情報の作成・公表を行っている。

［長坂昂一・吉田隆］

『寺本俊彦ほか編『海洋学講座』全15巻（1972～1976・東京大学出版会）』▽『友田好文・高野健三著『地球科学講座4　海洋』（1983・共立出版）』▽『宇野木早苗・久保田雅久著『海洋の波と流れの科学』（1996・東海大学出版会）』▽『蒲生俊敬著『海洋の科学――深海底から探る』（1996・日本放送出版協会）』▽『池田八郎著『世界の海洋と漁業資源―――海洋と大気と魚』（1998・成山堂書店）』▽『熊沢源右衛門著『新しい海洋科学』改訂版（1999・成山堂書店）』▽『柳哲雄著『海の科学――海洋学入門』第2版（2001・恒星社厚生閣）』▽『日本海洋学会編『海と環境――海が変わると地球が変わる』（2001・講談社）』▽『村田良平著『海洋をめぐる世界と日本』（2001・成山堂書店）』▽『中島敏光著『海洋深層水の利用――21世紀の循環型資源』（2002・緑書房）』▽『福谷恒男著『海洋気象のABC』4訂版（2002・成山堂書店）』▽『福地章著『海洋気象講座』9訂版（2003・成山堂書店）』▽『豊田恵聖監修、東海大学海洋学部編『改訂　宇宙から深海底へ――図説海洋概論』（2003・講談社）』▽『関根義彦著『海洋物理学概論』4訂版（2003・成山堂書店）』▽『宇田道隆著『海』（岩波新書）』

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