Elucidation of the Active Geosphere. Kyoto University Acvtive Geosphere investigations for the 21st century COE Program
+ Asian Monsoon
A monsoon is defined as a seasonal change in direction of surface
prevailing wind direction especially between summer and winter. The
domain of monsoon includes the equatorial Africa, Indian Ocean, Indian
subcontinent, South-East Asia and East Asia. Since monsoon often
accompanies rainy or dry season, the word monsoon also indicates a
rainy season. Among the monsoon region, the monsoon in Asia (Asian
monsoon) has both the largest spacial scale and the strongest
circulation.
(S.T.)
+ Lithosphere
The upper layer of the solid Earth, comprising all crustal rocks and the brittle
part of the uppermost mantle, below which is the asthenosphere.
The lithosphere comprises numerous blocks, known as tectonic plates,
which have differential motions giving rise to the "plate tectonics".
Its thickness is variable, from 1-2 km at mid-oceanic ridge crest,
but generally increasing from 6 km near the ridge to 120-140 km beneath older oceanic crust.
The thickness of the lithosphere is believed to be governed by its thermal structure.
(O.M.)
+ El Nino/ La Nina
Large scale oscillation of the ocean and the atmosphere at 2 or 3
years intervals observed in the tropical Pacific. The phenomenon is
typically seen in the persistent interannual anomaly of the Sea
Surface Temperature in the eastern and the western tropical Pacific,
or the interannual change of the sea level pressure and the resultant
change of the easterly wind. Rescently, the signal of El Nino is found
in the other areas, and therefore, becomes to be known as the
quite important oscillation for the global climate.
(K.M.)
+ Water/Energy Flow
Recently, the human impact on the earth environment by the increase
of the greenhouse gas and the other anthropogenic products has become
serious. Its effect is not restricted to local phenomena but
prevailed by through the global water cycle and the re-distribution of
the heat and the energy accompanied by the various phase change. This
concept is very important to understand the individual earth
phenomenon in the context of the global climate change.
(K.M.)
+ Plate Tectonics
Plate tectonics is a theory that describes the dynamics of the Earth's
outer shell. The Earth's surface is made up of a mosaic of rigid plates,
moving very slowly with respect to each other. In the context of plate
tectonics, the relative movements of the rigid plates give rise to
earthquakes, mountain building, volcanism, and other phenomena.
(K.K.)
Total electron content (TEC)
Integral value of the electron density along a path.
Ground-based GPS receiver measures total number of the electron
along a path of the radio wave between the GPS orbit, 20,000km altitude,
and the ground. The F-region ionosphere around 300km altitude contributes
to the most of the GPS-TEC. 1 TEC unit is 1016 electron per a square meter.
(S.A.)
Strombolian eruption
Strombolian eruptions are characterized by the intermittent explosion
that throw out blocks and bombs or fountaining of basaltic lava from a crater.
They typically occur every few minutes or a few ten minutes, sometimes rhythmically.
Stromboli volcano which is located in the Mediterranean gave its name to this kind of eruption.
Mt. Mihara in Izu-Oshima island is known as the volcano showing Strombolian eruption.
(O.T.)