Nino is a phenomena that Sea Surface Temperature (SST) in
the tropical Pacific is warmer than normal state. The period
of El Nino is irregular, changes 2-7 years. The warm
event affects not only over the tropical Pacific region
happening El Nino but also over global region by the changes
of atmospheric circulation. Recently, it has been appreciated
the importance for study of El Nino as it is known that
El Nino cause unusual change in the weather. CDL (Climate
Dynamics Laboratory) study on dynamics and impacts of El
Nino and develop coupled model which forecast El Nino.
a) The Definition
: The definition of El Nino make a slightly difference
by scientists. In general, however, El Nino is defined
the period that the time, SST Anomaly in the Equatorial eastern
Pacific (Nino3 Index or Nino3.4 Index) is greater than 0.5C,
last 5 months.
b) What is La Nina?
La Nina is characterized by unusually cold ocean
temperatures in the Equatorial eastern Pacific. El Nino
and La Nina are not independent events but
opposite phases of the El Nino-Southern
Oscillation (ENSO) cycle, with La Nina sometimes
referred to as the cold phase of ENSO and El Nino
as the warm phase of ENSO.
c) Southern Oscillation?
El Nino results from interaction between the surface
layers of the ocean and the overlying atmosphere in tropical
Pacific. Southern Oscillation is the seasaw oscillation
of Sea level pressure in the tropics. SST warming is oceanic
response, Southern Oscillation is atmospheric response by
SST change associated with El Nino and La Nina. Therefore
El Nino and Southern Oscillation (ENSO) is coupled mode
of atmosphere and ocean system.
d) The Origin of the Name,
El Nino were originally recognized by fisherman
off the coast of South America as the appearance of unusually
warm water in the Pacific ocean. El Nino means The Little One in Spanish. This name was
used often the tendency of the phenomenon to arrive around
e) How often does El Nino occur?
El Nino's usually occur irregularly, approximately
every two to seven years. The El Nino years 1976-1977, 1982-1983,
1986-1987, 1991-1994 and 1997-1998 are distinguished by
large SST anomalies. The first half of the 1990's is unusual
in that the past four years have all been unusually warm
in the equatorial Pacific. El Nino typically last 12-18
- The global impacts of El-Nino
The twists and turns in the interaction between
ocean and atmosphere in the Pacific can have a ripple
effect on climatic conditions in global region.
With El Nino, the period October through March
tends to be wetter than usual in a swath extending from
southern California eastward across Arizona, southern
Nevada and Utah, New Mexico, and into Texas. There are
more rainy days, and there is more rain per rainy day.
El Nino winters can be two to three times wetter than
La Nina winters in this region.
In the Pacific Northwest, El Nino tends to
bring drier winters. The area affected in this manner
includes Washington, Oregon, and the more mountainous
portions of Idaho, western Montana and northwest Wyoming.
This area of influence extends well up into Canada,
and coincides very well with the Columbia River Basin
on both sides of the U.S./Canada border.
Winter temperatures with
El Nino conditions tend to be warmer than usual from
Washington and northern Oregon across the northern tier
to Montana, also along the West Coast and East Asia.
In general, in all these regions, La Nina
climate effects are approximately, but not exactly,
opposite to El Nino climate effects.
shows the relation
of El-Nino and temperature in korea. Marked E in figures
appears the period of El-Nino. In El-Nino summer, temperature
in korea is mostly cool than normal temperature of summer. Only one
case of warm events is warmer than normal in summer. The case of
winter, the temperature during El-Nino period tend to be warmer
than normal. For 15 warm events, only two case was cold, the
others are normal or warm. The relation of El-Nino and
precipitation in Korea is not significant, compared to the temperature
relation, but precipitation in summer tend to increase than
normal value during El-Nino period.
Temperature and Precipitation in Korea
during El-Nino period
effects on typhoon which caused extensive damage. Figure
points of Typhoon which passed into Korea. During El-Nino period,
generation region of Typhoon located in the south compared to
non El-Nino period. It is reason that convergence structure
in the tropics is changed by El-Nino. The moving path of
the typhoon is more long and regular. It can be understand
that the change of the North Pacific high effects on the