Marine meteorological and hydrological information

Including nautical meteorological and hydrological reports, forecasts, warnings and facsimile charts. Provided by the marine meteorology and hydrology department. The meteorological and hydrological information at sea is more concise in words than on land; The configuration and dynamics of the weather system on the fax weather map are convenient for navigators to guess the weather phenomena of related routes or vast sea areas. At present, there are many weather systems or weather forecast indicators used by navigators to read fax weather maps: indicators of the movement and development of fronts, cyclones and anticyclones, indicators of the strengthening and weakening of tropical cyclones, and so on. These forecast indicators have developed from qualitative indicators to quantitative indicators, and there are also quantitative indicators for local sea areas. In addition, there are various nomograms for estimating wind speed, and tables showing the relationship between approximate wave height and wind power level. , used to read the fax weather map. In order to overcome language barriers and facilitate communication, the World Meteorological Organization has stipulated meteorological codes suitable for navigation practice and unified meanings of numbers and symbols on maps. The compilation of ship meteorological data must be carried out in accordance with the International Ship Meteorological Code, and ships in various countries have their own regulations. The weather map of the ship, including its fax map, is different from the weather map used by the land meteorological station: first, it is much simpler; Second, its main scope is in the ocean; Third, the drawings are limited to show only related items closely related to navigation. Whether it is the fax weather map broadcast to ships or the ship weather map released by ports all over the world, different scales are used according to needs. At present, 1:20000000 is usually adopted. For the convenience of navigators, the paper surface of the map should not exceed 50×60 cm. Ship weather report is the information about weather and sea conditions released to ships by marine meteorological and hydrological departments through radio stations in a planned and regular manner. The World Meteorological Organization has published a special book on the name, broadcasting time, frequency and weather bulletin of the World Department of Marine Meteorology and Hydrology.