7.6 EI Nino and Southern Oscillation
231
roared through woodlands near Melbourne, and volatile eucalyptus trees ignited explosively. In all, 75 people lost their lives, 8000 became homeless, and
a million acres of forest and farmland were destroyed. By the time rains came
again in March 1983, the Australian agricultural economy had shriveled. Farm
income fell by nearly half, and farm related losses totaled two and a half billion
dollars (Canby, 1984).
Since 1983, Australian meteorologists have been active in searching for possible linkages between EI Nino, especially the SOl, and changes in the frequency,
location, and intensity of tropical cyclone activity in the eastern Australian
region, droughts, low river flow in the Darling River, outbreaks of mosquitoborne Murray Valley encephalitis in southern Australia, and other phenomena
(Nicholls, 1986, 1991). Other aspects of teleconnections in large-scale features
of atmospheric circulation, especially those related to El Nino, have recently
been discussed by Trenberth et al. (1998) using the TOGA experiment evidence.
In the community's perception, an EI Nino event is a 'bad time' and its impact
on human activities is adverse. However, as was pointed out by Philander
(1990), the years with EI Nino were known in Peru as arias de abundancia
(the years of abundance), when the sea is full of wonders, the land even more
so. First of all desert becomes a garden... The soil is soaked by the heavy
downpour, and within a few weeks the whole country is covered by abundant
pasture. The natural increase of flocks is practically doubled and cotton can be
grown in places where in other years vegetation seems impossible (Philander,
1990). At that time, the shallow waters off Peru are full of yellow and black
water snakes. However, the birds and marine life that usually are abundant
temporarily disappear. Arntz (1984) also provided some examples of positive
changes associated with the 1982-83 EI Nino.
7.6.4 Observing and Forecasting EI Nino
As was showed above, observing EI Nino has a long history, starting from individual local observations to more coordinated field work in the 1970s and
early 1980s. Apart from these achievements, an understanding of the physical
processes responsible for the EI Nino cycle is still limited. The real breakthrough was initiated by the recently completed TOGA experiment. A major
accomplishment of TOGA was the development of an ocean observing system to
support seasonal-to-inter annual climate studies. The main TOGA observing
system components included in situ oceanographic measurements (an island
and coastal tide gauge network, drifting buoys arrays, moored buoys to provide surface wind, SST and current mea~mrements, volunteer observing ship and
expendable bathythermograph program for upper ocean temperature profiles);
satellite measurements (SST, sea level and wind measurements), and in situ meteorological measurements from an expanded World Weather Watch network
(McPhaden et at., 1998). For each type of measurement, specific resolution and
accuracy requirements were established and by the end of TOGA it was found
231
roared through woodlands near Melbourne, and volatile eucalyptus trees ignited explosively. In all, 75 people lost their lives, 8000 became homeless, and
a million acres of forest and farmland were destroyed. By the time rains came
again in March 1983, the Australian agricultural economy had shriveled. Farm
income fell by nearly half, and farm related losses totaled two and a half billion
dollars (Canby, 1984).
Since 1983, Australian meteorologists have been active in searching for possible linkages between EI Nino, especially the SOl, and changes in the frequency,
location, and intensity of tropical cyclone activity in the eastern Australian
region, droughts, low river flow in the Darling River, outbreaks of mosquitoborne Murray Valley encephalitis in southern Australia, and other phenomena
(Nicholls, 1986, 1991). Other aspects of teleconnections in large-scale features
of atmospheric circulation, especially those related to El Nino, have recently
been discussed by Trenberth et al. (1998) using the TOGA experiment evidence.
In the community's perception, an EI Nino event is a 'bad time' and its impact
on human activities is adverse. However, as was pointed out by Philander
(1990), the years with EI Nino were known in Peru as arias de abundancia
(the years of abundance), when the sea is full of wonders, the land even more
so. First of all desert becomes a garden... The soil is soaked by the heavy
downpour, and within a few weeks the whole country is covered by abundant
pasture. The natural increase of flocks is practically doubled and cotton can be
grown in places where in other years vegetation seems impossible (Philander,
1990). At that time, the shallow waters off Peru are full of yellow and black
water snakes. However, the birds and marine life that usually are abundant
temporarily disappear. Arntz (1984) also provided some examples of positive
changes associated with the 1982-83 EI Nino.
7.6.4 Observing and Forecasting EI Nino
As was showed above, observing EI Nino has a long history, starting from individual local observations to more coordinated field work in the 1970s and
early 1980s. Apart from these achievements, an understanding of the physical
processes responsible for the EI Nino cycle is still limited. The real breakthrough was initiated by the recently completed TOGA experiment. A major
accomplishment of TOGA was the development of an ocean observing system to
support seasonal-to-inter annual climate studies. The main TOGA observing
system components included in situ oceanographic measurements (an island
and coastal tide gauge network, drifting buoys arrays, moored buoys to provide surface wind, SST and current mea~mrements, volunteer observing ship and
expendable bathythermograph program for upper ocean temperature profiles);
satellite measurements (SST, sea level and wind measurements), and in situ meteorological measurements from an expanded World Weather Watch network
(McPhaden et at., 1998). For each type of measurement, specific resolution and
accuracy requirements were established and by the end of TOGA it was found