Geoscience Reference
In-Depth Information
Table 23.1.
Data sets used in the compilation of time series shown in
Figure 23.2
.
(The means and standard deviations were calculated for the 1911-1960 reference
period; adapted from Whetton et al.,
1990
, table 1.)
Standard
deviation
Data set
Record length
Mean
Units
Southern Oscillation Index
1870-1986
0.18
0.79
North China Rainfall Index
1970-1979
3.07
0.44
India rainfall
1871-1985
992.2
82.6
mm
10
6
Ml
Krishna River discharge
1901-1960
57.1
14.5
Comparison of the 500-year record of wet and dry years in China (Anon.,
1981
)and
the corresponding flood record of the Nile with the updated El Ni no record from Peru
revealed some previously unsuspected correlations. Whetton et al. (
1990
) carried out
time series analysis of rainfall and river flow in India, wet and dry years in China, and
corresponding values of the SOI (
Tables 23.1
and
23.2
;
Figure 23.2
). These authors
were the first to show that in eastern China during the period 1870-1979, years of
strongly negative SOI coincided with a poor monsoon in the three key agricultural
regions shown in
Figure 23.3
.
In much of peninsular India since at least the year 1871, years of severe drought
are generally (but not invariably) years of strongly negative SOI (
Figure 23.2
).
Tabl e
23.1
specifies the data sets used by Whetton et al. (
1990
) in compiling the time
series shown in
Figure 23.2
and
Table 23.2
. (An update of this analysis would be
Table 23.2.
Statistically significant correlations between China rainfall, India
droughts, Java tree rings, Nile flood height and El Ni no occurrences in Peru for
different time intervals between 1740 and 1984. (Nile floods and Java tree rings
correlated significantly during the 1750s and from 1870 to 1929 [0.01]; adapted
from Whetton et al.,
1992
, fig. 25, with supplementary data from Whetton and
Rutherfurd,
1994
.)
Significant
correlation
Locality A
Locality B
Time interval
Significance
1
El Ni no
North China rainfall
1770-1879
0.08
2
El Ni no
Nile floods
1770-1869
1880-1984
0.08
0.001
3
El Ni no
India droughts
1770-1869
0.03
4
El Ni no
Java tree rings
1770-1984
0.01
5
Nile floods
North China rainfall
1870-1984
0.01
6
Nile floods
India droughts
1770-1879
1880-1984
0.05
0.01
7
India droughts
North China rainfall
1870-1984
0.001
