159
water mass, rather other factors like sea bed rise or tectonic reasons are also considered with significant proofs behind sea level rise (Raha et al. 2002).
As a regional case study in a mangrove dominated zone, it’s of course a fact that
temperature has increased in three sectors (western, central and eastern) of Indian
Sundarbans by 4.47%, 4.55% and 4.92% respectively as documented by the present
author with a data set of 30 years (1984–2013) for 18 different stations (Table 6.2
and Fig. 6.1).
The surface water temperature exhibited an increasing trend in all the three sectors of this lower Gangetic region. In the western sector, the rate of increase ranges
between 0.04 °C/year (at Saptamukhi) to 0.06 °C/year (at Jambu Island) (Fig. 6.2).
In the central sector, the rate of increase ranges from 0.04 °C/year (at Dhulibasani)
to 0.05 °C/year (at Thakuran, Chulkathi, Goasaba and Pirkhali) (Fig. 6.3). The eastern sector, adjacent to Bangladesh Sundarbans exhibited similar increase in trend
with values ranging from 0.05 °C/year (at Harinbhanga, Khatuajhuri, Chamta and
Chandkhali) to 0.06 °C/year (at Arbesi) (Fig. 6.4).
The overall increase in surface water temperature during the study period ranges
from 3.73% (at Saptamukhi) to 5.59% (at Jambu Island) in the study region.
The forecast method predicts that in the western, central and eastern sectors of
the lower Gangetic region, the surface water temperature can reach up to 34.9 °C,
35.0 °C and 35.2 °C respectively during 2043 (Figs. 6.5, 6.6, and 6.7) compared to
the present average value of 32.8 °C, 32.6 °C and 32.7 °C respectively. Thus after a
period of 30 years from 2013 April, there will be a rise of 6.40%, 7.36% and 7.65%
in the western, central and eastern sectors respectively in the present mangrove
dominated geographical locale.
Table 6.2 Sampling stations in the western, central and eastern sectors of Indian Sundarbans
Sectors
Sampling stations
Latitude
Longitude
Western sector
Stn. 1
Muriganga (W 1 )
21°38′25.86′′N
88°08′53.55′′E
Stn. 2
Saptamukhi (W 2 )
21°36′02.49′′N
88°23′47.18′′E
Stn. 3
Jambu Island (W 3 )
21°35′42.03′′N
88°10′22.76′′E
Stn. 4
Lothian (W 4 )
21°38′21.20′′N
88°20′29.32′′E
Stn. 5
Sagar Island (W 5 )
21°38′51.55′′N
88°02′20.97′′E
Stn. 6
Prentice Island (W 6 )
21°42′40.97′′N
88°17′10.04′′E
Central sector
Stn. 7
Thakuran Char (C 1 )
21°49′43.17′′N
88°33′21.57′′E
Stn. 8
Dhulibasani (C 2 )
21°47′06.62′′N
88°33′48.20′′E
Stn. 9
Chulkathi (C 3 )
21°41′53.62′′N
88°34′10.31′′E
Stn. 10
Goashaba (C 4 )
21°43′50.64′′N
88°46′41.44′′E
Stn. 11
Matla (C 5 )
21°53′15.30′′N
88°44′08.74′′E
Stn. 12
Pirkhali (C 6 )
22°06′00.97′′N
88°51′06.04′′E
Eastern Sector
Stn. 13
Arbesi (E 1 )
22°11′43.14′′N
89°01′09.04′′E
Stn. 14
Jhilla (E 2 )
22°09′51.53′′N
88°57′57.07′′E
Stn. 15
Harinbhanga (E 3 )
21°57′17.85′′N
88°59′33.24′′E
Stn. 16
Khatuajhuri (E 4 )
22°03′06.55′′N
89°01′05.33′′E
Stn. 17
Chamta (E 5 )
21°53′18.56′′N
88°57′11.40′′E
Stn. 18
Chandkhali (E 6 )
21°51′13.59′′N
89°00′44.68′′E
6 Mangroves: A Potential Vegetation Against Sea Level Rise
water mass, rather other factors like sea bed rise or tectonic reasons are also considered with significant proofs behind sea level rise (Raha et al. 2002).
As a regional case study in a mangrove dominated zone, it’s of course a fact that
temperature has increased in three sectors (western, central and eastern) of Indian
Sundarbans by 4.47%, 4.55% and 4.92% respectively as documented by the present
author with a data set of 30 years (1984–2013) for 18 different stations (Table 6.2
and Fig. 6.1).
The surface water temperature exhibited an increasing trend in all the three sectors of this lower Gangetic region. In the western sector, the rate of increase ranges
between 0.04 °C/year (at Saptamukhi) to 0.06 °C/year (at Jambu Island) (Fig. 6.2).
In the central sector, the rate of increase ranges from 0.04 °C/year (at Dhulibasani)
to 0.05 °C/year (at Thakuran, Chulkathi, Goasaba and Pirkhali) (Fig. 6.3). The eastern sector, adjacent to Bangladesh Sundarbans exhibited similar increase in trend
with values ranging from 0.05 °C/year (at Harinbhanga, Khatuajhuri, Chamta and
Chandkhali) to 0.06 °C/year (at Arbesi) (Fig. 6.4).
The overall increase in surface water temperature during the study period ranges
from 3.73% (at Saptamukhi) to 5.59% (at Jambu Island) in the study region.
The forecast method predicts that in the western, central and eastern sectors of
the lower Gangetic region, the surface water temperature can reach up to 34.9 °C,
35.0 °C and 35.2 °C respectively during 2043 (Figs. 6.5, 6.6, and 6.7) compared to
the present average value of 32.8 °C, 32.6 °C and 32.7 °C respectively. Thus after a
period of 30 years from 2013 April, there will be a rise of 6.40%, 7.36% and 7.65%
in the western, central and eastern sectors respectively in the present mangrove
dominated geographical locale.
Table 6.2 Sampling stations in the western, central and eastern sectors of Indian Sundarbans
Sectors
Sampling stations
Latitude
Longitude
Western sector
Stn. 1
Muriganga (W 1 )
21°38′25.86′′N
88°08′53.55′′E
Stn. 2
Saptamukhi (W 2 )
21°36′02.49′′N
88°23′47.18′′E
Stn. 3
Jambu Island (W 3 )
21°35′42.03′′N
88°10′22.76′′E
Stn. 4
Lothian (W 4 )
21°38′21.20′′N
88°20′29.32′′E
Stn. 5
Sagar Island (W 5 )
21°38′51.55′′N
88°02′20.97′′E
Stn. 6
Prentice Island (W 6 )
21°42′40.97′′N
88°17′10.04′′E
Central sector
Stn. 7
Thakuran Char (C 1 )
21°49′43.17′′N
88°33′21.57′′E
Stn. 8
Dhulibasani (C 2 )
21°47′06.62′′N
88°33′48.20′′E
Stn. 9
Chulkathi (C 3 )
21°41′53.62′′N
88°34′10.31′′E
Stn. 10
Goashaba (C 4 )
21°43′50.64′′N
88°46′41.44′′E
Stn. 11
Matla (C 5 )
21°53′15.30′′N
88°44′08.74′′E
Stn. 12
Pirkhali (C 6 )
22°06′00.97′′N
88°51′06.04′′E
Eastern Sector
Stn. 13
Arbesi (E 1 )
22°11′43.14′′N
89°01′09.04′′E
Stn. 14
Jhilla (E 2 )
22°09′51.53′′N
88°57′57.07′′E
Stn. 15
Harinbhanga (E 3 )
21°57′17.85′′N
88°59′33.24′′E
Stn. 16
Khatuajhuri (E 4 )
22°03′06.55′′N
89°01′05.33′′E
Stn. 17
Chamta (E 5 )
21°53′18.56′′N
88°57′11.40′′E
Stn. 18
Chandkhali (E 6 )
21°51′13.59′′N
89°00′44.68′′E
6 Mangroves: A Potential Vegetation Against Sea Level Rise