4.5.4 Correlation of NPP with Climate Variability
Historical of climate data show that Kalimantan terrestrial has experienced substantial with inter-annual variations and spatial variations in temperature and
rainfall during the study period and tightly associated with ENSO. However, ENSO has correlated with temperature and precipitation. Correlation between
NPP and climate variability in this study are used as estimation data during normal year in 2005 and during ENSO year 2006 El Nino Event and 2007 La
Nina event.
10 20
30 40
50 60
70 80
90 100
J an-
1 Ju
l- 1
J an-
2 Ju
l- 2
J an-
3 Ju
l- 3
J an-
4 Ju
l- 4
J an-
5 Ju
l- 5
J an-
6 Ju
l- 6
J an-
7 Ju
l- 7
J an-
8 Ju
l- 8
J an-
9 Ju
l- 9
J an-
1 Ju
l- 1
Time gC
m
-2
m ont
h
-1
24 24.5
25 25.5
26 26.5
27
o
C
NPP Mean TEMP Mean
Figure 14 Time series data of NPP and Temperature in Kalimantan
Figure 14 illustrates changes in the amount of monthly mean of NPP and average temperature in Kalimantan between 2001 and 2010. During the 10-year
period, the amount of both monthly mean of NPP and average precipitation varied a lot and the two graphs showed many upward and downward trends. The figure
of temperature peaked in May 2010 and that of NPP in April 2010. During normal year, average maximum temperature reached on April,
May, and June and decreased in other monthly period. In addition, average maximum of precipitation reached in November, December, and January and for
the other monthly period until July the precipitation decreased. Distribution of the monthly mean of NPP show an increase in April and May and in other monthly
period until August the NPP distribution was stable. Increased of NPP occurs in the month of May.
During El Nino year, average maximum of temperature reached in May and other monthly period temperature was decreased. However, average
maximum of precipitation reached in December and decreased in other monthly
period, meanwhile in October to November the precipitation increased. The distribution NPP value showed an increase until May and in other monthly period
until October the NPP distribution was decreased. Increase of NPP occurs in April followed with increasing in precipitation.
During La Nina year, average maximum of temperature reached in April and decreased in other monthly period. However, maximum average of
precipitation was reached in December and decreased during other monthly period, meanwhile in July to December the precipitation increased. The monthly mean
distribution of NPP value showed an increase in April and in other monthly period until June, the NPP distribution was pretty stable. However, an increase of
monthly mean of NPP distribution occurs in August followed with an increase of precipitation during this period.
Chart Title y = 0.0196x + 24.477
R
2
= 0.3202
24.8 25
25.2 25.4
25.6 25.8
26 26.2
26.4 26.6
26.8 27
20 40
60 80
100 TEMP Mean
Linear TEMP Mean
Figure 15 Correlation between NPP and Temperature data in Kalimantan
Fig the ave
ure 15 shows that the average of NPP was moderately correlated with rage temperature during the 10-year period in Kalimantan with a value of
R
2
0.3202.
10 20
30 40
50 60
70 80
90 100
Ja n-0
1 Ju
l-0 1
Ja n-
02 Ju
l-02 Ja
n-0 3
Ju l-0
3 Ja
n-0 4
Ju l-0
4 Ja
n- 05
Ju l-05
Ja n-0
6 Ju
l-0 6
Ja n-
07 Ju
l-0 7
Ja n-
08 Ju
l-08 Ja
n-0 9
Ju l-0
9 Ja
n- 10
Ju l-1
Time gC
m
-2
mo nt
h
-1
50 100
150 200
250 300
350 400
mm mo
nt h
NPP Mean PPT Mean
Figure 16 Time series data of NPP and Precipitation in Kalimantan
Figure 16 shows the relation between the amount of the mean of NPP and precipitation mean in Kalimantan from 2001 to 2010. In the beginning of 2001,
the average precipitation value was by far higher that that of NPP. However, the amount of average precipitation fell dramatically after January 2001, whereas the
proportion of NPP increased rapidly after a minimal drop. During the 10-year period, the value of NPP climbed in the beginning of every year, and a lot of
changes happened during the rest of the year. The Figure 14 showed that the average precipitation peaked in January 2009 and the lowest proportion in August
2004. On the other hand, the mean of NPP graph shows many variations throughout the period. The amount varies from 34 gC m
-2
month
-1
to 86 gC m
-2
month
-1
.
0.05 0.1
0.15 0.2
0.25 0.3
0.35 0.4
0.45 0.5
1 2
3 4
5 6
7 8
9 10
11 12
13
Month R
R
Figure 17 Correlation between NPP and Precipitation data in Kalimantan
Figure 17 shows that the correlation between the average of NPP and precipitation could be considered as low to moderate correlation with a time lag of
four months. The precipitation was four months in advance before the NPP. Changes of NPP are closely correlated with increase temperature and
changing precipitation. Precipitation increases in most Kalimantan areas during La Nina event. Since increase in precipitation is accompanied by increasing
clouds cover and decreasing sunlight and radiation, the increased NPP is small. The decreased NPP also correlated with the rapidly increasing of temperature and
the decreasing of precipitation.
4.5.5 Spatial distribution of NPP in Kalimantan