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Impact of Climate Change on Tropical Cyclones Frequency and Intensity on Indian Coasts

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Climate change is projected to exacerbate intensity of tropical cyclonic storms in selected ocean basins with the rise in sea surface temperatures. Almost all of the tropical cyclonic storms are concentrated in the East Asia, North America, and the Central American regions. The North Indian Ocean—the Bay of Bengal and the Arabian Sea, generates only 7% of the world’s cyclones. However, their impact is comparatively high and devastating, especially when they strike the East Indian and Bangladesh coasts bordering the North Bay of Bengal due to high population density clustered around low lying areas along these coastlines. The tropical storms typically do not reach a high intensity in the Arabian Sea due to the unfavorable wind shear; dry air feed from Thar Desert and relatively lower sea surface temperatures. However, the Arabian Sea basin has also produced a few strong tropical cyclones particularly as seen in the recent years. In general, cyclones in North Indian Ocean tend to peak during May, October and November. This paper presents comprehensive analyses of the cyclonic disturbances data of the North Indian Ocean of 140 years (1877–2016) and investigates the likely impacts of climate change on tropical cyclones frequency and intensity on Indian coasts based on historical cyclone data and recent model based findings on plausible changes in Indian Ocean SSTs and circulation systems. © 2019, Springer International Publishing AG, part of Springer Nature.
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1Chapter 32
2Impact of Climate Change on Tropical
3Cyclones Frequency and Intensity
4on Indian Coasts
5Sushil Gupta, Indu Jain, Pushpendra Johari and Murari Lal
6Abstract Climate change is projected to exacerbate intensity of tropical cyclonic
7storms in selected ocean basins with the rise in sea surface temperatures. Almost all
8of the tropical cyclonic storms are concentrated in the East Asia, North America,
9and the Central American regions. The North Indian Oceanthe Bay of Bengal and
10 the Arabian Sea, generates only 7% of the worlds cyclones. However, their impact
11 is comparatively high and devastating, especially when they strike the East Indian
12 and Bangladesh coasts bordering the North Bay of Bengal due to high population
13 density clustered around low lying areas along these coastlines. The tropical storms
14 typically do not reach a high intensity in the Arabian Sea due to the unfavorable
15 wind shear; dry air feed from Thar Desert and relatively lower sea surface tem-
16 peratures. However, the Arabian Sea basin has also produced a few strong tropical
17 cyclones particularly as seen in the recent years. In general, cyclones in North
18 Indian Ocean tend to peak during May, October and November. This paper presents
19 comprehensive analyses of the cyclonic disturbances data of the North Indian
20 Ocean of 140 years (18772016) and investigates the likely impacts of climate
21 change on tropical cyclones frequency and intensity on Indian coasts based on
22 historical cyclone data and recent model based ndings on plausible changes in
23 Indian Ocean SSTs and circulation systems.
24 Keywords North Indian Ocean Climate models Tropical cyclone
25 Sea surface temperature Cyclonic storm Severe cyclonic storm
26
S. Gupta (&)I. Jain P. Johari M. Lal
RMSI, Noida, India
e-mail: sushil.Gupta@rmsi.com
I. Jain
e-mail: indu.jain@rmsi.com
P. Johari
e-mail: pushpendra.johari@rmsi.com
M. Lal
e-mail: murari.lal@rmsi.com
Layout: T1 Standard Book ID: 447463_1_En Book ISBN: 978-3-319-77275-2
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©Springer International Publishing AG, part of Springer Nature 2019
P. J. Rao et al. (eds.), Proceedings of International Conference on Remote Sensing
for Disaster Management, Springer Series in Geomechanics and Geoengineering,
https://doi.org/10.1007/978-3-319-77276-9_32
1
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27 1 Introduction
28 Tropical cyclones are among the most damaging natural hazards of the world. The
29 North Indian Ocean (NIO) accounts for about 7% of global Tropical Cyclones
30 (TCs). Out of these 7% of the cyclones, most forms in the Bay of Bengal
31 (BoB) than the Arabian Sea (AS), which is about 4 times higher [1,2]. In NIO,
32 there are two cyclone seasons: pre-monsoon (March to May, MAM) and
33 post-monsoon (October to December, OND). Some of the cyclonic disturbances
34 also form in transitional monsoon season (June to September, JJAS). However,
35 during the peak summer monsoon season, the depressions and deep depressions in
36 BoB generally do not intensify to cyclonic storm category due to moderate vertical
37 wind shear. On an average about 56 TCs form in the BoB and the AS every year,
38 of which 23 reach severe stage. Most of the severe cyclones of the BoB form
39 during the post-monsoon season in the months of October and November. A few
40 severe cyclones form during May also but the post-monsoon cyclones are severest
41 due to which this season is also known as storm season in south Asia [3].
42 Tropical disturbances have resulted in colossal socio-economic losses to life and
43 property, especially along the east coast of India, Bangladesh and Myanmar every
44 year due to cyclones in the BoB. Due to the high population density and rapid
45 increase in infrastructure projects in the coastal regions of India, the economic
46 losses are increasing leaps and bound. However, loss of life has reduced in recent
47 years to a greater extent due to the advancement in science and technology of
48 cyclone warning facilities and evacuation of a large number of human populations
49 and animals prior to its landfall. The recent October 2013 Cyclone Phailin and the
50 October 2014 Cyclone Hudhud are the two examples on the east coast of India that
51 made landfall near Gopalpur on October 11 at about 2130 IST and at
52 Visakhapatnam on October 12 at about 1330 IST, respectively. For both of these
53 cyclones, the loss of lives have been reduced considerably, thanks to leanings from
54 1999 Odisha Super Cyclone in which more than 10,000 people perished; however,
55 economic losses of buildings and infrastructure have increased enormously. For
56 example, industrial losses in 2014 Cyclone Hudhud at Visakhapatnam city alone
57 surpassed over INR 4000 Crores, while total losses from this cyclone were esti-
58 mated over INR 36,000 Crores. Therefore, any change in the TCs frequency and
59 intensity in the BoB and AS would have far reaching socio-economic consequences
60 for India and neighbouring countries.
61 There have been a few studies on the long-term trends and TCs frequency and
62 intensity over the BoB [311]. The TCs data was analysed for a period of 122 years
63 during 18771998 [8,9], and for a period of 129 years during 18772005 [3]
64 (Table 1).
65 Most of these studies have emphasized a marginal decrease in the annual fre-
66 quency of cyclones; however, there is an increasing trend in the frequency of
67 Severe Cyclonic Storms (SCS) over NIO. Trend analysis reveal that the SCS fre-
68 quency over the BoB has registered signicant increasing trends in past 129 years
69 during the intense cyclonic months, though this does not necessarily imply that SCS
2 S. Gupta et al.
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70 frequency has increased continuously decade after decade [3]. In fact there has been
71 a slight decrease in SCS frequency after peaking during 19661970, although this
72 does not alter the long term trend much. Moreover, the intensication rate (denoted
73 hereafter by SCS/CS) during November, which accounts for highest number of
74 intense cyclones in the NIO, has registered a steep rise of 26% per hundred years,
75 implying that a tropical depression forming in the BoB during November has a high
76 probability to reach to severe cyclone stage [3].
77 This paper presents comprehensive analyses of the long-term cyclonic distur-
78 bance data of the NIO of the past 140 years (18772016) and investigates the likely
79 impacts of climate change on TCs frequency and intensity on Indian coasts (BoB,
80 AS) based on historical cyclonic disturbances and recent model based ndings on
81 plausible changes in Indian Ocean SSTs and circulation systems.
82 2 Decadal Frequency Analysis of Tropical Disturbances
83 The long-term decadal frequency analysis of tropical disturbances in the BoB and
84 AS for a duration of 140 years (18772016) has been presented in Figs. 1and 2,
85 respectively. The sources of tropical storms data are India Meteorological
86 Department publication (IMD) and International Best-Track Archive for Climate
87 Stewardship (IBTrACS).
88 It can be seen from Fig. 1, that there is a general decreasing trend in the decadal
89 frequency of cyclonic disturbances in monsoon, pre-monsoon, and post-monsoon
90 seasons from 1970s onwards in BoB. Similar observations can also be made in the
91 decadal frequency of cyclonic disturbances in monsoon, pre-monsoon, and
92 post-monsoon seasons from Fig. 2, over AS. Both these analyses also corroborate
93 the earlier studies (for example [3,12,13]).
94 3 Intensity Analysis of CS and SCS
95 As mentioned earlier, we have analysed 140 years of tropical cyclonic disturbances
96 data during 18772016. While, Singh [3] and other authors analysed this data as
97 total numbers of CS or SCS numbers (Table 1), we not only analysed it as CS or
Table 1 Frequency of TCs
in the BoB during 18772005 Type of tropical
disturbance
Month
May Jun. Sept. Oct. Nov.
Cyclonic storm (CS) 59 35 92 41 116
Severe cyclonic storm
(SCS)
44 5 40 16 65
SCS/CS 0.75 0.14 0.43 0.39 0.56
Modied after Singh [3]
32 Impact of Climate Change on Tropical Cyclones 3
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0
10
20
30
40
50
60
70
Monsoon-TS
Postmonsoon-TS
Premonsoon-TS
Fig. 1 Decadal frequency analysis of tropical disturbances (18772016) over BoB
0
1
2
3
4
5
6
7
8
9
Monsoon-TS
Postmonsoon-TS
Premonsoon-TS
Fig. 2 Decadal frequency analysis of tropical storms (18772016) over Arabian Sea
4 S. Gupta et al.
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98 SCS but also divided in two segments, i.e., pre- and post-1970, and 1980 and rate of
99 intensication (SCS/CS), so that we could analyse the impact of climate change on
100 TCs intensity for both BoB and AS (Tables 2,3,4and 5).
101 Table 2clearly shows that rate of intensication of tropical storm in the BoB has
102 increased signicantly in the months of May, Oct and Nov post 1980s. In general,
103 similar, observations could also be made for AS (Table 3), however, in the month
104 of October, it has not changed.
105 If we take it pre- and post-1970s, then the rate of intensication is much more
106 evident in the months of May, Oct and Nov in the BoB than pre- and post-1980s
107 (Table 4). Similarly, for AS, rate of intensication is now much more evident in
Table 2 Pre- and post-1980, intensity analysis of CS and SCS over Bay of Bengal
Type of tropical
cyclone
Pre-1980 Post-1980
May Jun. Sept. Oct. Nov. May Jun. Sept. Oct. Nov.
CS 7 2629 3411 0 1 1 6 4
SCS 14 2 14 18 30 5 0 0 12 15
SCS/CS 2.00 0.08 0.48 0.53 2.73 INF –– 2.00 3.75
Table 3 Pre- and post-1980, intensity analysis of CS and SCS over Arabian Sea
Type of tropical
cyclone
Pre-1980 Post-1980
May Jun. Sept. Oct. Nov. May Jun. Sept. Oct. Nov.
CS 2 3 2 7 4 0 1 0 1 1
SCS 3 2 2 7 16 2 2 0 1 3
SCS/CS 1.50 0.67 1.00 1.00 4.00 INF 2 1.00 3.00
Table 4 Pre- and post-1970, intensity analysis of CS and SCS over Bay of Bengal
Type of tropical
cyclone
Pre-1970 Post-1970
May Jun. Sept. Oct. Nov. May Jun. Sept. Oct. Nov.
CS 6 25 27 30 10 1 2 3 10 5
SCS 13 2 11 17 22 6 0 3 13 23
SCS/CS 2.17 0.08 0.41 0.57 2.20 6.00 1.00 1.30 4.60
Table 5 Pre- and post-1980, intensity analysis of CS and SCS over Arabian Sea
Type of tropical
cyclone
Pre-1970 Post-1970
May Jun. Sept. Oct. Nov. May Jun. Sept. Oct. Nov.
CS 1 3 2 6 4 1 1 0 2 1
SCS 3 2 1 6 12 2 2 1 2 7
SCS/CS 3.00 0.67 0.50 1.00 3.00 2.00 2.00 INF 1.00 7.00
32 Impact of Climate Change on Tropical Cyclones 5
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108 pre- and post-1970s than pre- and post-1980s for the month of May, Oct and Nov
109 (Table 4) and this change could be attributed to the recent warming as a conse-
110 quence of impacts of ongoing climate change.
111 4 The Inuence of Climate Change on Tropical Cyclones
112 In a study [14], the behavior of Indian summer monsoon in a high resolution
113 climate model and reported that under double CO
2
conditions, fewer cyclonic
114 depressions formed in the month of June. The historical cyclonic disturbances data
115 studied in this paper also corroborate this nding.
116 Another study published in Nature Geosciences [15] reported that future pro-
117 jections based on theory and high-resolution dynamical models consistently indi-
118 cate that greenhouse warming will cause the globally averaged intensity of TCs to
119 shift towards stronger storms, with intensity increases of 211% by 2100. Existing
120 modeling studies also consistently project decreases in the globally averaged fre-
121 quency of TCs, by 634%. Balanced against this, higher resolution modeling
122 studies typically project substantial increases in the frequency of the most intense
123 cyclones, and increases of the order of 20% in the precipitation rate within 100 km
124 of the storm centre.
125 Recent global climate models continue to project future decreases in global TC
126 numbers. However, increases in the intensities of the strongest storms and increased
127 rainfall rates are projected. Some studies suggest that, by the end of the century, the
128 number of category 4 and 5 cyclones is expected to double, with heavier rainfall
129 [16]. Globally, the consensus projection is for decreases in TC numbers by about 5
130 30%, increases in the frequency of categories 4 and 5 storms by 025%, an increase
131 of 05% in typical lifetime maximum intensity, and increases in TC rainfall rate by
132 520% [16]. Recent high-resolution modeling studies suggest that the frequency of
133 the most intense storms, which are associated with particularly extensive physical
134 effects, will more likely than not increase substantially in some basins under pro-
135 jected 21st century warming and there is medium condence that TC rainfall rates
136 will increase in every affected region [16]. We obtain similar results for both BoB
137 and AS basins from our analysis of the downscaled high resolution global model
138 data sets produced under CMIP5 experiments. Detailed data analysis is still in
139 progress to strengthen our ndings which would be published elsewhere.
140 5 Conclusions
141 Our analysis of long-term 140 years of cyclonic disturbances demonstrates that
142 there is a general decreasing trend in the decadal frequency of cyclonic disturbances
143 in monsoon, pre-monsoon, and post-monsoon seasons from 1970s onwards in both
144 BoB and Arabian Sea. Moreover, there is a general increasing trend in the Intensity
6 S. Gupta et al.
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145 of TCs pre- and post-1970s and 1980s in the months of May, Oct and Nov. This
146 change could be attributed to the recent rising trends of BoB and AS as a conse-
147 quence of impacts of ongoing climate change. The high resolution climate model
148 analysis also suggests that the frequency of the most intense storms in Bay of
149 Bengal and Arabian Sea will likely to increase under projected warming during the
150 21st century while the total number of cyclonic disturbances should decrease. The
151 analysis also suggests an increase of 1015% in the rainfall associated with these
152 disturbances within the area under inuence of the storm winds.
153 References
154 1. Dube, S.K., Rao, A.D., Sinha, P.C., Murty, T.S., Bahuleyan, N.: Storm surge in Bay of
155 Bengal and Arabian Sea: the problem and its prediction. Mausam 48, 288304 (1997)
156 2. Mohanty, U.C., Niyogi, D., Tripathy, S., Marks, F.D., Gopalakrishnan, S.G., Tallapragada,
157 V.: Predicting landfalls, tropical cyclones, eye on the storm. IUSSTF Connect 4(2) (2012)
158 3. Singh, O.P.: Long-term trends in the frequency of severe cyclones of Bay of Bengal:
159 observations and simulations. Mausam 58,5966 (2007)
160 4. Mooley, D.A.: Severe cyclonic storms in the Bay of Bengal, 18771977. Monsoon Weather
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162 5. Mooley, D.A.: Increase in the frequency of the severe cyclonic storms of the Bay after 1964
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169 8. Singh, O.P., Khan, T.M.A., Rahman, S.: Changes in the frequency of tropical cyclones over
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173 10. Srivastav, A.K., SinhaRay, K.C., De, U.S.: Trends in the frequency of cyclonic disturbances
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175 11. Sikka, D.R.: Major advances in understanding and prediction of tropical cyclones over the
176 north Indian Ocean: a perspective. Mausam 57, 165196 (2006)
177 12. Mande, K.S., Bhide, U.V.: A study of decreasing storm frequency over Bay of Bengal. J. Ind.
178 Geophys. Union 7(2), 5358 (2003)
179 13. Climate Council: Cranking up the intensity: climate change and extreme weather events.
180 Accessed at https://www.climatecouncil.org.au/cranking-intensity-report (2017)
181 14. Lal, M., Bengtsson, L., Cubasch, U., Esch., M., Schlese, U..: Synoptic scale disturbances of
182 the Indian summer monsoon as simulated in a high resolution model. Clim Res. 5, 243248
183 (1995)
184 15. Knutson, T.R. McBride J.L., Emanuel, J.C.K., Holland G., Landsea, C., Held, I., Kossin, J.P.,
185 Srivastava, A.K., Sugi, M.: Tropical cyclones and climate change. Nat. Geosci. 3, 157163
186 (2010). https://doi.org/10.1038/ngeo0779
187 16. Christensen, J.H., Krishna Kumar, K., Aldrian, E., An S.-I., Cavalcanti, I.F.A., DeCastro, M.,
188 Dong, W., Goswami, P., Hall, A., Kanyanga, J.K., et al.: Climate phenomena and their
189 relevance for future regional climate change. In: Climate change: the physical science basis.
190 Contribution of Working Group I to the Fifth Assessment Report of the IPCC AR5.
191 Cambridge University Press, Cambridge (2013)
32 Impact of Climate Change on Tropical Cyclones 7
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... Previous works identified the decreasing trend of the frequency of TCs worldwide. However, there is an increasing trend in the intensity of TCs that was identified for the BoB region during the pre-and post-monsoon seasons for the 1970s and 1980s (Gupta et al. 2019). This increasing trend of TCs in the BoB region could be attributed to the impacts of climate change (Gupta et al. 2019). ...
... However, there is an increasing trend in the intensity of TCs that was identified for the BoB region during the pre-and post-monsoon seasons for the 1970s and 1980s (Gupta et al. 2019). This increasing trend of TCs in the BoB region could be attributed to the impacts of climate change (Gupta et al. 2019). The works of Emanuel et al. (2004), Persing andMontgomery (2003), andMontgomery et al. (2006) justified the increase in intensity and frequency of TCs under warmer climates (Sarthi et al. 2015). ...
... The works of Emanuel et al. (2004), Persing andMontgomery (2003), andMontgomery et al. (2006) justified the increase in intensity and frequency of TCs under warmer climates (Sarthi et al. 2015). Furthermore, the outputs of climate models suggest an increase in the intensity of TCs in the BoB region in the future (Gupta et al. 2019). However, the coastal region of the BoB is highly vulnerable to cyclones and associated storm surges because of its dense population and the existence of a number of cities in the area (Yesubabu et al. 2019). ...
Chapter
Full-text available
Bangladesh is struggling with an increasing trend of environmental degradation due to the adverse shocks of climate change. Rajshahi, a northwestern city of Bangladesh, is mostly vulnerable to drought, heat waves, air and water pollution, etc. Although various earlier studies regarding environmental governance are mostly focused on mega cities such as Dhaka, studies on medium-sized cities are less frequently highlighted. Thus, achieving sustainable government through environmental governance in the medium-sized city is an urgent issue for academia and policy makers alike. Local environmental governance plays a significant role in attaining local sustainable development. In Bangladesh, the local government authorities perform a wide range of development activities in the cities. To understand local sustainable development, the environmental impact of these development activities must be explored. The main purpose of this chapter is to investigate the overall status of environmental governance for promoting sustainable development considering environmental issues in development programs. This investigation is empirical research mainly based on primary data as collected from the government officials and field staff of the Rajshahi City Cooperation, and various stakeholders of the city, e.g., residents and civil society, through questionnaire surveys and key informant interviews, including a case study. The central finding indicates that the state of environmental governance for sustainable development at the Rajshahi City Cooperation is functionally poor. Despite having a policy framework for prioritizing environmental issues in the development activities of the city, a huge gap still remains between policies and practices. The findings of the study may assist the policy makers and concerned authorities in formulating policies and taking initiatives to ensure environmental governance to strengthen sustainable development in the urban areas of Bangladesh.
... Several researchers have conducted studies on cyclonic storms and their associated impact on the environment. Among them Rahman et al. (2017) investigated the impacts of cyclonic storm Aila on the mangrove forest of the Sundarban region in Bangladesh, Datta and Deb (2012) identified the coastal land use/land cover changes in the Indian Sunderban using remotely sensed data, Mishra and Panigrahi (2014) studied the impact of the storm on the south Odisha coast, Kar and Bandhyopadhyay (2015) analysed Tropical storm Aila in the Gosaba Block of Indian Sundarban, Srinivasa (2015) (Scanlon et al. 2002) investigated the impact of tropical cyclone Hudhud on the coastal region of Visakhapatnam, Hossain and Karlson (2017) investigated the Land Cover Change in the Sundarbans Caused by Cyclone Roanu, Debnath (2018) examined the land use and land cover change detection of the Gosaba Island of the Indian Sundarban, Gupta et al. (2018) investigated the impact of climate change on tropical cyclones frequency and intensity on Indian coasts, Priyadarshini et al. (2019) identified the land cover change dynamics of the Gaja cyclone in coastal Tamil Nadu, Sarkhel et al. (2019) pointed out the impact on the Coastal Belts of Odisha, and Ghosh and Mistri (2020) explored the coastal agriculture and its challenges on the Gosaba Island of Indian Sundarban. ...
Chapter
Surface water and ground water are used for agricultural, industrial, and domestic purposes. Rainfall and the corresponding runoff generated are important hydrological processes which depend on the local physiographic, climatic, and biotic factors. Remotely sensed data provide valuable and real-time spatial information on natural resources and physical parameter. Due to climate changes and human interference to the river systems, flood risks have also increased. Flood losses can be reduced by proper floodplain management. Watershed means a naturally occurring hydrologic unit that contributes storm runoff to a single waterway classified on the basis of its geographical area. The aim of the study is to throw some light on the importance of watershed management using geospatial techniques. In this analysis, studies of the slope, contour, and terrain profile of study area and behavior of stream segments, drainage direction, flow accumulation, Land Use Land Cover (LULC), drainage map, etc. were carried out using QGIS-ArcMap 10.1. There are two river basins in upper Tapi region—one is Tapi River and the other is Purna River. Results show the depletion of both ground and surface water in the watershed. Green cover is considerably reduced in the region, and hence, the watershed is less humid and dry. Study also reveals that due to change in land use and land cover, there are more wastelands in the watershed. The study also provides an indication to restore the vegetation cover and will be able to help policy and decision-makers to understand the importance of watershed and need for its characteristics analysis.
... Several researchers have conducted studies on cyclonic storms and their associated impact on the environment. Among them Rahman et al. (2017) investigated the impacts of cyclonic storm Aila on the mangrove forest of the Sundarban region in Bangladesh, Datta and Deb (2012) identified the coastal land use/land cover changes in the Indian Sunderban using remotely sensed data, Mishra and Panigrahi (2014) studied the impact of the storm on the south Odisha coast, Kar and Bandhyopadhyay (2015) analysed Tropical storm Aila in the Gosaba Block of Indian Sundarban, Srinivasa (2015) (Scanlon et al. 2002) investigated the impact of tropical cyclone Hudhud on the coastal region of Visakhapatnam, Hossain and Karlson (2017) investigated the Land Cover Change in the Sundarbans Caused by Cyclone Roanu, Debnath (2018) examined the land use and land cover change detection of the Gosaba Island of the Indian Sundarban, Gupta et al. (2018) investigated the impact of climate change on tropical cyclones frequency and intensity on Indian coasts, Priyadarshini et al. (2019) identified the land cover change dynamics of the Gaja cyclone in coastal Tamil Nadu, Sarkhel et al. (2019) pointed out the impact on the Coastal Belts of Odisha, and Ghosh and Mistri (2020) explored the coastal agriculture and its challenges on the Gosaba Island of Indian Sundarban. ...
Chapter
Climate change has put tremendous impact on the environment in the current scenario. The consequences are extensive consequences on the atmosphere, agronomy, water resources, biome, natural reserves, budget, biodiversity, and social security. Odisha, lying in the Eastern Coast of India connecting the Bay of Bengal, has a stretch of 480 km of coastline and is always vulnerable to climate change in terms of heavy storm like cyclones, beach erosion, coastal flooding, storm swell, and denudation. This state has scores of agro-climatic sectors which require improvement in the shape of diverse reworking approaches keeping pace with the ongoing scenario of climate change. Adaptation strategies such as agriculture, fisheries and animal husbandry, water, health, and coastal and disaster risk management have been formulated looking at the vulnerability, food security, and other parameters. Major steps have been initiated to mitigate the impact of climate change; still a lot of further strategies need to be dealt with to keep the region safe and disaster free. These include energy, urban development, transport, industries, and waste disposal. Proper attention must be adhered to embracing judicious policies on energy efficiency based on enactment, modifying state building codes and development codes to improve LULC, transportation, and energy productivities, establishment of new renewable energy policies, assortment and related criterions and reinforce multi-segment parameters to cater to the upcoming challenges related to reduction in poverty and increasing the adaptive capacity. Several initiatives have been undertaken in the government, private, and NGO sectors, but still lack of proper vision, appropriate mission, and slow pace of implementation has jeopardized the entire development.
... However, there is a statistically significant increase in the number of higher category tropical cyclones in southern Africa. The findings confirm observations from other studies that climate change will cause an increase in high-impact tropical cyclones in the region and there is a general reduction in the frequency of lower category tropical cyclones (Gupta et al., 2019;Lee et al., 2020;Xiao, 2021). ...
Book
The subject of tropical cyclones in Southern Africa, also known as hurricanes or typhoons in other regions of the world, has been growing over the past few decades. However, there is still limited literature on foundational and fundamental topics on the matter. To this end, this book addresses this gap, citing some examples from both historic and recent tropical cyclones. The book presents meteorological and climatic aspects of tropical cyclones, including reviews on forecasting, warning message dissemination and public response aspects of early warning systems with a focus on the Tropical Cyclones Idai and Kenneth. Fundamentals in disaster risk reduction (DRR) are also discussed moving from the provisions of the Hyogo Framework for Action (2005–2015), to the Sendai Framework for Disaster Risk Reduction (2015–2030). Climate change issues are central to the publication, as well as the role of information and communication technologies in DRR and management. The book also tackles some challenges and opportunities associated with the implementation of regional legal and institutional frameworks on DRR. The book comes as part of a series with three volumes. The other volumes include “Cyclones in Southern Africa Vol. 1: Interfacing the Catastrophic Impact of Cyclone Idai with SDGs in Zimbabwe” and “Cyclones in Southern Africa Vol 3: Implications for the Sustainable Development Goals”. To this end, this book is suitable as a read for several professionals and disciplines such as tourism and hospitality studies, economics, sustainable development, development studies, environmental sciences, arts, geography, life sciences, politics, planning and public health.
... However, there is a statistically significant increase in the number of higher category tropical cyclones in southern Africa. The findings confirm observations from other studies that climate change will cause an increase in high-impact tropical cyclones in the region and there is a general reduction in the frequency of lower category tropical cyclones (Gupta et al., 2019;Lee et al., 2020;Xiao, 2021). ...
Chapter
Reducing the risk of disasters including climate change risks calls for dynamic policies, strategies, plans and programmes that are underpinned by global frameworks on disaster risk reduction (DRR), climate change adaptation (CCA) and sustainable development. As with most parts of the world, current DRR policy architecture in southern Africa is predominantly response oriented as evidenced by the 2019 cyclones Idai and Kenneth as well as unprecedented flooding and other hazards that affect the region. This chapter seeks to provide the foundational knowledge on the fundamentals of DRR, converging on resilience, with an amplification of the role played by climate change in increasing disaster risk. An integrative review of literature on DRR and CCA in general, and a documentary review of reports, international policies on DRR and CCA and national policies in the countries affected by the 2019 cyclones and floods, was conducted. The 2019 transboundary cyclones provide an opportunity to review existing DRR strategies whose inadequacy in addressing vulnerability, exposure and disaster risks in the region requires attention. This chapter provides the essential DRR, CCA and sustainable development theoretical grounding for the diverse thematic areas explored in greater detail in this book volume.
... However, there is a statistically significant increase in the number of higher category tropical cyclones in southern Africa. The findings confirm observations from other studies that climate change will cause an increase in high-impact tropical cyclones in the region and there is a general reduction in the frequency of lower category tropical cyclones (Gupta et al., 2019;Lee et al., 2020;Xiao, 2021). ...
Chapter
Tropical Cyclone Idai ripped through Malawi, Madagascar, Mozambique and Zimbabwe in mid-March 2019. Hundreds of lives were lost and a lot more remain unaccounted for. This study investigates the extent to which Zimbabwe’s information and communication technology (ICT) is ready for disaster risk reduction (DRR) application and management. The focus was on Chimanimani District, where Cyclone Idai hit eastern Zimbabwe on 15 March 2019. This work further investigates the damage to ICT infrastructure and its resilience to the cyclone. Through the use of a questionnaire survey, interviews, document analysis and field observations, it emerged that Zimbabwe’s application of ICT in early warning systems remained low and ineffective due to the lack of appropriate equipment and expertise and unreliable electricity supply. In Chimanimani, some mobile network service providers’ base stations were flooded and communication was cut off completely, while mobile penetration at household level is near 100%. Grid electricity was also cut off for close to 1 month, with secondary impacts on charging mobile devices and signal coverage. Mobile phones and social media platforms such as WhatsApp were widely used at all DRR cycle stages, while radio provided the widest reach in terms of public announcements. From these findings, we recommend that authorities should invest heavily in modernising national weather forecasting ICT and promote the use of mobile phones as one of the platforms for DRR, especially in early warning. There is also the need to raise disaster awareness and preparedness among communities in Chimanimani.
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The food security of any household largely depends on the security or sustainability of livelihoods. The livelihood security of the households of the southwestern coastal region of Bangladesh is immensely affected by various climatic conditions and disasters. The present research is intended to conduct a very in-depth study on the impact of cyclonic disaster on all types of livelihood capitals (i.e., natural, physical, human, social, and financial capital) and the relevance of such impacts to the food security conditions of the study area. The results of the present study show that the percentages of livelihood related to food production are decreasing because of a cyclonic disaster-induced unfavorable environment in the study area. The decreased employment opportunities reducing the income level also lowered the purchasing capacity for food and other daily basic necessities. Thus, switching occupation or migrating to other places seems to be the only option to them to survive. Such a change of occupation and land use that are related to food production would decrease the food supply of the area. In order to maintain sustainable livelihood and food security for households of the study area the long-term disaster resilience plan and policies should be taken and implemented for vulnerable coastal areas such as Shyamnagar Upazila.
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The series of annual frequency of severe cyclonic storms which struck the coast around the Bay of Bengal during the period 1877-1977 has been examined to find out if any significant change has occurred in the mean frequency, It is observed that while the series for the period is homogeneous, a highly significant increase in the mean annual frequency has occurred after 1964. The larger annual mean frequency may be due to better facilities of detection of severe storms and/ or meteorological conditions over the Bay being more frequently favourable for intensification of storms into severe storms, An estimate of the mean annual frequency is made for the next 50-year period and the frequency distribution on the basis of this mean is given for the period, utilising the Poisson probability model which has shown good fit to past data.
Article
lkj & mRrjh fgUn egklkxj esa m".kdfVca/kh pØokrksa ij fd, x, vuqla/kku xr 150 o"kksZa esa fofHkUu pj.kksa ls xqtjs gSa vkSj vf/kd rFkk csgrj izs{k.kksa dks fodflr djus ds fy, izkS|ksfxdh ds :Ik es bldk fodkl fd;k x;k gSA 20oha 'krkCnh ds e/; rd leqnz esa bl vkinkdkjh ifj?kVuk ds cuus vkSj blds rhoz gksus dh tkudkjh iksrksa esa gh dqN gn rd fojyrk ls izkIr gksus okys izs{k.kksa ds ek/;e ls feyrh Fkh vkSj blfy, 1960 ds n’kd rd Hkkjr esa fd, x, vf/kdka’k vuqla/kku v/;;uksa esa pØokrksa ds tyok;q foKku] mudh /kjkryh; lajpuk] mudh xfr vkSj leqnz esa tgktksa dks ig¡qpkusa okyh {kfr dks vuns[kk djus okys fu;eksa ij vf/kd cy fn;k x;k FkkA ekSle jsMkj] mifjru ok;q ifjKkiuksa] vuqla/kku ok;q;ku losZ{k.k ekSle mixzgksa vkSj daI;wVjksa ds ek/;e ls izkIr dh xbZ ubZ ok;qeaMyh; izks|ksfxdh ds izLrqrhdj.k ls 1950 ds n’kd ls ysdj 1980 ds n’kd ds nkSjku fofHkUu ns’kksa ds m".kdfVca/kh pØokr vuqla/kku esa vk’p;Ztud :Ik ls ifjorZu vk;k gSA bl vof/k esa m".kdfVca/kh pØokrksa ds laiw.kZ mRifRr pØ dk izfr:i.k djus ds fy, lS)kafrd v/;;uksa vkSj daI;wVj fun’kksaZ ds fodkl esa lq/kkj ns[kk x;k gSA bl vof/k esa m".kdfVca/kh pØokr ds ekxZ dk iwokZuqeku yxkuk Hkh vuqla/kku dk ,d {ks= cu x;k gS vkSj 1950 ds n’kd ls ysdj 1980 ds n’kd ds nkSjku tyok;q foKku] flukfIVd lkaf[;dh; vkSj xfrdh; i)fr;ksa ij vk/kkfjr rduhdksa ds izdkjksa esa fujarj fodkl gqvk gS rFkk bUgsa ekU;rk feyh gSA xr 10 o"kksZa dh vof/k ds nkSjku fodflr ns’kksa esa HkweaMyh; ifjpkyu fun’kksZa esa fufgr ifj"Ñr mPp foHksnu ds fun’kksZa dk fodkl fd;k x;k gS vkSj ikjLifjd fØ;kvksa dh izfØ;k ds :Ik esa bl Ik)fr dk fodkl djus vkSj bldh xfr dk iwokZuqeku yxkus ds fy, budh tk¡p dh xbZ gSA ;s iw.kZ :i ls lgh ikbZ xbZ gSaA Hkkjr esa Hkh bl izdkj ds fodklksa dks viuk;k x;k gSA bl 'kks/k&i= esa m".kdfVca/kh pØokr ds fodkl vkSj bldh xfr esa lfUufgr izR;{k izfØ;kvksa ds laca/k esa fd, x, izeq[k fodklksa dh lwph miyC/k djkus dk iz;kl fd;k x;k gSA lkekU; :Ik ls HkweaMyh; vuqla/kku ds {ks= esa fd, x, iz;kl fgan egklkxj csflu esa fd, tk jgs v/;;uksa ij dsafnzr jgs gSaA mRrjh fgan egklkxj esa m".kdfVca/kh pØokrksa ds vUr% nl o"khZ; fHkUurkvksa dh tk¡p dh xbZ gS vkSj 1980 ds n’kd ls budh xfr;ksa esa vDlj vR;kf/kd deh ns[kh xbZ gSA fgan egklkxj csflu esa m".k@'khr bulksa dh ?kVukvksa ds e/; dksbZ laca/k ugha ik;k x;k gSA izpaM m".kdfVca/kh pØokrksa ds fodkl vkSj xfr ds fy, vko’;d o`gr eku fLFkfr;ksa dh izÑfr ls lacaf/kr izs{k.kkRed vkSj lS}kafrd ekWMfyax i)fr;ksa esa daI;wVj izfr:i.kksa lfgr izs{k.kkRed vkSj lS)kafrd i)fr;ksa ls fHkUu fHkUu fopkjksa dk irk pyk gSA mRrjh fgan egklkxj csflu esa fd, x, vkSj vf/kd vuqla/kku dh vksj fo’ks"k /;ku nsus dh fn’kk esa dqN lq>ko fn, x, gSaA Research on tropical cyclones in the north Indian Ocean has passed through different phases in the last 150 years and progress was made as the technology for more and better observations evolved. Till the middle of the 20th century, the only way of knowing about the formation and intensification of this disastrous phenomenon, while out at sea, was through rather sparse ship observations and hence the climatology of the cyclones, their surface structure, movement and the rules to avoid the damage to shipping at sea were emphasized in most of the research studies in India till 1960s. Introduction of new atmospheric technologies through weather radars, upper air soundings, weather satellites and computers have brought a phenomenal change in tropical cyclone research in different countries during 1950s to 1980s. The period also witnessed break-through in theoretical studies and the development of computer models to simulate the complete genesis cycle of tropical cyclones. Predicting the track of tropical cyclone also became an area of active research in this period and a variety of techniques were increasingly developed. During the last 10 years sophisticated high resolution models embedded within global circulation models have been developed in advanced countries and tested for predicting the development and movement of the system as an interactive process. In India, too such developments have been adopted. Within the scope of global research effort in general, the focus of the article is on the studies in north Indian Ocean basin. Inter-decadal variation of tropical cyclones in the north Indian Ocean has been examined and the frequency of their formations have shown drastic decrease since 1980s. No connection is found between the warm/cold ENSO events in the Indian Ocean basin and tropical cyclone frequency in the basin. Observational and theoretical approaches with computer simulations have brought a convergence of views concerning the nature of large-scale conditions needed for development and movement of severe tropical cyclones. Some suggestions are provided for directing special attention toward further research in this area in the north Indian Ocean basin.
Article
Trends in cyclonic disturbances for the period 1891-1997 were studied over Bay of Bengal and Arabian Sea. It is noticed that there is a significant decreasing trend at 99% level of confidence in the frequency of storms. The slopes of decreasing trend in cyclonic activity over Bay of Bengal and that over Arabian Sea were found to be maximum during last four decades. Weakening of Hadley circulation due to upper tropospheric warming may be one of the cause of this decreasing trend. There appears to be decrease in intensification of cyclonic disturbances in recent period.
Article
An effort has been made to settle the question whether the intense cyclones have become more frequent over the north Indian Ocean, posing a more serious threat to the vulnerable coastal population of the region. The results of the study, which has considered the entire existing data of 122 years of tropical cyclone frequency over the north Indian Ocean from 1877 to 1998, have shown that there is indeed a trend in the enhanced cyclogenesis during November and May. These months account for the maximum number of severe cyclones over the north Indian Ocean, The increasing trend in the cyclone frequency during these months has been primarily due to the significant positive trends over the Bay of Bengal, where the majority of north Indian Ocean cyclones develop. Thus the coastal regions of Bangladesh, India and Myanmar have indeed become more prone to the incidence of severe cyclones during November and May. There has been a two-fold increase in the tropical cyclone frequency over the Bay of Bengal during November in the past 122 years. There has been a 17% increase in the intensification rate of cyclonic disturbances to the cyclone stage, and a 25% increase to severe cyclone stage over the north Indian Ocean during November, which accounts for highest monthly average of severe cyclone frequency, All these linear trends are statistically significant at 99% level. The increasing trend in the cyclone frequency during May is also highly significant but the intensification rates to cyclone and severe cyclone stages have registered only slight increasing tendencies. The cyclonic frequencies during transitional monsoon months, June and September, have diminished considerably. The detailed results have been presented for November and May only.
Article
The east coast of India and the coasts of Bangladesh, Myanmar and Sri Lanka are vulnerable to the incidence of tropical cyclones of the Bay of Bengal. Every year these cyclones inflict heavy loss of life and property in this region. Global climate change resulting from anthropogenic activity is likely to manifest itself in the weather and climate of the Bay of Bengal region also. The long-term trends in the frequency and intensity of tropical cyclones of the Bay of Bengal during intense cyclonic months May, October and November is one such problem which has been addressed in the present paper. Utilizing the existing data of 129 years (1877-2005) pertaining to the tropical cyclone frequency and intensity in the Bay of Bengal during May, October and November, a study was undertaken to investigate the trends in the frequency of Severe Cyclonic Storms (SCS) during past decades. The results of the trend analysis reveal that the SCS frequency over the Bay of Bengal has registered significant increasing trends in past 129 years during the intense cyclonic months. It may be emphasized that these trends are long-term trends for more than hundred years based on statistical analyses which do not necessarily imply that SCS frequency has increased continuously decade after decade. As a matter of fact there has been a slight decrease in SCS frequency after peaking in the pentad 1966-1970, but this does not alter the long-term trend much. The intensification rate during November, which accounts for highest number of intense cyclones in the north Indian Ocean, has registered a steep rise of 26% per hundred years, implying that a tropical depression forming in the Bay of Bengal during November has a high probability to reach to severe cyclone stage. A regional climate model simulation revealed the enhanced cyclogenesis in the Bay of Bengal during May, October and November as a result of increased anthropogenic emissions in the atmosphere.
Article
An examination of the severe cyclonic storms which formed over the Bay of Bengal and those which struck the coast during the period 1877-1977 brings out a higher mean annual frequency, and a higher percentage of storms intensifying into severe storms, during the period 19659-77.-from Author
Article
Changes in the frequency of tropical cyclones developing over the Arabian Sea and the Bay of Bengal have been studied utilizing 122 year (1877–1998) data of tropical cyclone frequency. There have been significant increasing trends in the cyclone frequency over the Bay of Bengal during November and May which are main cyclone months. During transitional monsoon months; June and September however, the frequency has decreased. The results have been presented for five months, i.e., May-November which are relevant as far as tropical cyclone frequency over the Arabian Sea and the Bay of Bengal are concerned. The tropical cyclone frequency in the Arabian Sea has not shown any significant trend, probably due to small normal frequency. The frequency time series has been subjected to the spectral analysis to obtain the significant periods. The cyclone frequency over the Bay of Bengal during May has shown a 29 year cycle. A significant 44 year cycle has been found during November. Over the Arabian Sea significant cycles of 13 and 10 years have been observed during May-June and November, respectively. The tropical cyclone frequency in the North Indian Ocean has a prominent El Niño-Southern Oscillation (ENSO) scale cycle (2–5 years) during all above five months. The annual cyclone frequency exhibits 29 year and ENSO scale (2–4 years) oscillations. There is a reduction in tropical cyclone activity over the Bay of Bengal in severe cyclone months May and November during warm phases of ENSO. Examination of the frequencies of severe cyclones with maximum sustained winds ≥ 48 knots has revealed that these cyclones have become more frequent in the North Indian Ocean during intense cyclone period of the year. The rate of intensification of tropical disturbances to severe cyclone stage has registered an upward trend.
Article
Bangladesh is frequently visited by natural disasters such as tropical cyclones, storm surges, floods, droughts, tornadoes, and norwesters. Of these, tropical cyclones originating in the Bay of Bengal and associated storm surges are the most disastrous. There are various reasons for the disastrous effects of cyclones and storm surges in Bangladesh. Superimposed on these disastrous effects, climate change and any consequent sea level rise are likely to add fuel to the fire. Arise in temperature is likely to change cyclone activity: cyclone intensity, if not cyclone frequency, may increase. As a result, storm surges may also increase substantially. Sea level rise, an increase in cyclone intensity, and consequent increases in storm surge heights will have disastrous effects on a deltaic country like Bangladesh, which is not much above the mean sea level. This paper examines the climatology of cyclones in the Bay of Bengal for the last 110 years and trends in cyclone frequency and intensity. The phenomenon of storm surges in the Bay of Bengal is examined along with the primary reasons for the severity of storm surges in Bangladesh. The paper discusses both qualitatively and quantitatively the impacts of rises in temperature on tropical cyclone intensity in Bangladesh. With the use of a mathematical model developed for the simulation of storm surges along the Bangladesh coast; various scenarios of storm surges are developed. Using lower and upper bounds of sea surface temperature rise of 2 and 4C and of sea level rise of 0.3 and 1.0 m (according to the Intergovernmental Panel on Climate Change standard), the model simulates the maximum possible surges that are likely to occur under these conditions.