cloud distribution and height, upper-and lower-tropospheric winds estimated from cloud motion, sea surface temperature distribution, etc. These are basic data used for daily weather forecasting, long-range forecasting and oceanographic forecasting. They are especially important for predicting the movement of typhoons, fronts and
cyclones over the ocean where conventional meteorological data are very sparse.
(2) Upper-air Observations
Twice or four times a day, balloons to observe atmospheric pressure, air temperature, humidity and wind direction and speed at altitudes up to about 30km are released from 18 upper-air observation stations, plus five meteorological observation ships.
(3) Weather Radar Observations
A weather radar is used to continuously and instantaneously observe the three-dimensional distribution of rain droplets over a wide area with high spatial resolution. It is a powerful tool for observing the range of rainfall area, the precipitation intensity, the movement of rainfall area associated with a typhoon or a severe storm. JMA has a nationwide network of 19 weather radars to cover the whole country. Furthermore, airport weather radars are located at the nation's major airports. Including two doppler radars at Narita and kansai International airports.
(4) Surface Observations
As many as 162 meteorological offices in the country are observing atmospheric pressure, air temperature, humidity, wind direction and speed, precipitation, snow coverage, solar radiation, sunshine duration, cloud conditions, visibility, weather, etc. These data are used for weather forecasting and are accumulated for statistics to obtain climatological data.
Automatic observation facilities, called AMeDAS are located at 1,316 observation sites including meteorological observation stations to monitor four meteorological elements: air temperature, wind direction and speed, precipitation and sunshine duration. Furthermore, automatic snow gauges are located at 214 sites in heavy snowfall areas to monitor snow depth. Every hour the observation sites automatically report data within ten minutes after observations to the AMeDAS Center in Tokyo. At the center, these data are automatically edited and processed by a computer, and are promptly distributed to the meteorological offices.
(5) Oceanographic and Marine
Meteorological Observations
There are 66 tidal stations along the coast of Japan which contribute to the activities to protect the people and coastal facilities from tsunami, storm surges and unusual tides. The stations are equipped with a telemetering system for transmitting tidal information to the tidal forecast center, so that abnormal phenomena can be surely monitored.
JMA has six meteorological observation ships. They observe sea water temperature, salinity, ocean currents, chemical components, plankton, etc., and monitor the background levels of heavy metals and petroleum pollution and greenhouse gases of ocean and atmosphere in the water adjacent to Japan and the Western Pacific. They also conduct marine meteorological observations, radar meteorological observations and upper-air observations.
4 Climate Program
Abnormal weather events, such as hot and cold waves, excessive rainfall, and drought, occurred in all parts of the world have great impacts on global socio-economic activities today. In recent years, global environmental issues have been of great concern including global warming, depletion of ozone layer, deforestation, desertification, and acid rain induced by human activities.
(1) Climate Monitoring/Observation
In addition to the regular meteorological and marine meteorological observations, JMA carries out routine observations of atmospheric ozone, greenhouse gas concentrations, sea surface and sea water temperatures to monitor climate change and abnormal weather events. The observed data are processed at the Ozone Layer Monitoring
Office, the Japan Climatic Data Center which partly serves as the WMO World Data Center for Greenhouse Gases (WDCGG) and El Nino Monitoring Center, for distribution to the public.
