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equatorial band of the western sector of the Paci
c Ocean. Minimum SAT anom-
alies were observed in a broad band of the central and north-eastern regions of the
Paci
c Ocean (including a decrease of SAT). An analysis of observational data
revealed the prevailing of positive temperature anomalies in 1999 in many regions
of the globe. The most apparent anomalous situations include both warming and
cooling, including:
(1) The cold wave observed in January has brought a SAT decrease in Norway,
Sweden, and in some regions of Russia to the levels not observed since the late
19th century.
(2) A temperature decrease in February in Western Europe was followed, in
particular, by heavy snowfalls in the Alps.
(3)
In Western Australia the SAT decreased to values below the norm, though an
extreme warming in early January has led to intensive brush
res.
(4) The March temperature in Iceland was at a minimum for the last 20 years.
(5)
In April, powerful heat waves formed in the northern and central regions of
India, and in July and August
—
in the north-eastern and middle-western
regions of the USA.
(6) Unusually hot and dry weather was observed in the western part of Russia
(SAT anomalies in the central and north-western regions of the European
territory of Russia exceeded 5
°
C).
7) On the Australian continent, maximum average SAT in November
—
December turned out to be the lowest after 1950.
(8) The second half of the year was colder (than usual) in central and southern
Africa; the Sahel region was colder, wetter, and with more clouds than during
the preceding years.
(9) The warming in the USA during the last 50 years was weaker than over the
rest of the globe, with a weak cooling in the eastern part of the USA.
The land and ocean surface temperature decrease in the tropics in 1999 was
determined by the year-long La Ni
a event. This year was characterized by a great
number of destructive meteorological catastrophes, especially
ñ
fl
floods. In Australia,
USA, and Asia there was a multitude of tropical storms,
in Europe
—
heavy
snowfalls, avalanches, and storms; in the USA
the drought and tornado.
The global mean annual SAT value in the late 20th century exceeded by more
than 0.6
—
°
C the value recorded in the late 19th century (the error of this estimate
±
dence level). Analysis of the SAT observational
data suggested the conclusion that from the beginning of 1850, there has been an
irregular but substantial trend of climate warming on a global scale. This trend was
very weak in the period from the mid-19th century till 1910, and then it increased to
0.1
0.2
°
C corresponds to a 95 % con
-
1940 and during the last two decades). Two positive episodes of cooling were
separated by the interval of a weak cooling, especially in the Northern Hemisphere.
In the periods from 1951
°
C during 10 years (from combined data on SAT and SST in the period 1910
1990 the sign of the inter-hemispherical
difference of temperatures changed: the Northern Hemisphere became colder than
the Southern Hemisphere.
-
1960 to 1981
-
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