Acquisition: 632003 Acquisition: 4182004
Acquisition: 652004
Acquisition: 7232004 Acquisition: 4212005
Acquisition: 7102005
Acquisition: 8112005 Acquisition: 1012006
Legend Wm
-2
Figure 12. Distribution energy for soil heat flux Wm
-2
in Karawang district
4.1.10. Sensible Heat Flux
Distribution energy used to heat air or sensible heat flux is shown in Figure 13. Sensible heat flux ranges from 50-100 Wm
-2
and for several areas are
43
about 100-150 Wm
-2
. Except data in October 01, 2006 where total energy used is higher than the other data about 100-200 Wm
-2
. The dry months before October 2006 is long i.e. about 4-5 months, therefore the total energy used to heat air is
high.
Acquisition: 632003 Acquisition: 4182004
Acquisition: 652004
Acquisition: 7232004 Acquisition: 4212005
Acquisition: 7102005
Acquisition: 8112005 Acquisition: 1012006
Legend Wm
-2
Figure 13. Distribution energy for sensible heat flux in Karawang district
44
4.1.11. Evapotranspiration
The total energy used for evapotranspiration ranged from 100-200 Wm
-2
. Figure 14 presents distribution of energy use for evapotranspiration in Karawang
district for vegetation or non vegetation cover. Based on October 2006 data, the distribution is different from other data, because part of Karawang area uses
energy about 50-100 Wm
-2
. It shows that amount of water content in soil or vegetation is low than total energy needed for evaporation. Land cover such as
water body, fish pond and cloud needs higher energy about 200-250 Wm
-2
. It indicates that an area covers with water or cloud needs more energy for
evaporation. Furthermore, it will decrease total energy used for soil and air heating.
Acquisition: 632003 Acquisition: 4182004
Acquisition: 652004
Acquisition: 7232004 Acquisition: 4212005
Acquisition: 7102005
45
Acquisition: 8112005 Acquisition: 1012006
Legend Wm
-2
Figure 14. Distribution energy for evapotranspiration in Karawang district
4.1.12. Evaporative Fraction
Evaporative fraction constitutes index value from ratio amount of energy used for evapotranspiration with amount of net radiation minus soil heat flux. EF
value is near or equal one indicating this area is not potential of drought. It is caused by amount of energy focused to evapotranspiration process like
transpiration and evaporation. The water balance in soil and vegetation is sufficient for transpiration process of crops and evaporation of the land. This
drought indication occurs if amount of energy used for evapotranspiration is low, because soil and vegetation water content is little. EF value is near or equal zero
indicating this area is potential of drought. Table 11. Total area of evaporative fraction EF in Karawang district
632003 4182004 652004 7232004 4212005 7102005 8112005 1012006
0-0.1 2
9 2
2,980 0.1-0.2
7 6
2 107
8 12,371
0.2-0.3 103
120 54
744 6
32 114
26,028 0.3-0.4
2,636 2,423
1,018 2,105
18 290
1,105 35,673
0.4-0.5 23,141
16,663 8,322
5,404 197
1,725 5,842
35,257 0.5-0.6
46,567 72,356
48,117 16,599
6,880 4,687
16,207 29,567
0.6-0.7 57,529
62,839 61,347
30,174 56,934
10,089 37,320
26,077 0.7-0.8
34,590 17,777
36,808 28,655
77,267 35,343
54,107 19,811
0.8-0.9 7,571
1,231 10,130
25,554 18,953
67,100 51,531
5,180 0.9-1.0
75 7,062
64,069 15,493
52,103 6,677
233 No Data
21,022 19,825
20,382 19,822
17,493 21,871
20,329 63
Total 193,241
193,241 193,241
193,241 193,241
193,241 193,241
193,241 EF Date
Area ha
46
Acquisition: 632003 Acquisition: 4182004
Acquisition: 652004
Acquisition: 7232004 Acquisition: 4212005
Acquisition: 7102005
Acquisition: 8112005 Acquisition: 1012006
Legend Figure 15. Distribution of evaporative fraction EF in Karawang district
Table 11 and Figure 15 show the distribution of evaporative fraction. The dry or wet seasons in 2003-2005 have low potential of drought, because there is
enough water for evapotranspiration. Water source can be supplied by rain and
47
irrigation. On the contrary in 2006 there is a potential for drought in several locations of Karawang.
4.1.13. Irrigation
