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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 Ocean—the Bay of Bengal and
10 the Arabian Sea, generates only 7% of the world’s 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 (1877–2016) 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 findings 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
Chapter No.: 32 Date: 10-4-2018 Time: 10:40 am Page: 1/7
©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 5–6 TCs form in the BoB and the AS every year,
38 of which 2–3 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 [3–11]. The TCs data was analysed for a period of 122 years
63 during 1877–1998 [8,9], and for a period of 129 years during 1877–2005 [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 significant 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 1966–1970, although this
72 does not alter the long term trend much. Moreover, the intensification 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 (1877–2016) 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 findings 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 (1877–2016) 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 1877–2016. 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 1877–2005 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
Modified 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 (1877–2016) 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 (1877–2016) 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 intensification (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 intensification of tropical storm in the BoB has
102 increased significantly 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 intensification 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 intensification 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 Influence 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 finding.
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 2–11% by 2100. Existing
120 modeling studies also consistently project decreases in the globally averaged fre-
121 quency of TCs, by 6–34%. 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 0–25%, an increase
131 of 0–5% in typical lifetime maximum intensity, and increases in TC rainfall rate by
132 5–20% [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 confidence 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 findings 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 10–15% in the rainfall associated with these
152 disturbances within the area under influence 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, 288–304 (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 58,59–66 (2007)
160 4. Mooley, D.A.: Severe cyclonic storms in the Bay of Bengal, 1877–1977. Monsoon Weather
161 Rev. 108, 1647–1655 (1980)
162 5. Mooley, D.A.: Increase in the frequency of the severe cyclonic storms of the Bay after 1964—
163 possible causes. Mausam 32,35–40 (1981)
164 6. Ali, A.: Vulnerability of Bangladesh to climate change and sea level rise through tropical
165 cyclones and storm surges. J. Water Air Soil Pollut. 92d, 171–179 (1996)
166 7. Joseph, P.V.: Change in the frequency and tracks of tropical cyclones in the Indian Ocean
167 seas. Workshop on global change and tropical cyclone, Dhaka, Bangladesh, 18–21 Dec
168 (1995)
169 8. Singh, O.P., Khan, T.M.A., Rahman, S.: Changes in the frequency of tropical cyclones over
170 the North Indian Ocean. Meteorol. Atmos. Phys. 75,11–20 (2000)
171 9. Singh, O.P., Khan, T.M.A., Rahman, S.: Has the frequency of intense tropical cyclones
172 increased in the north Indian Ocean? Curr. Sci. 80, 575–580 (2001)
173 10. Srivastav, A.K., SinhaRay, K.C., De, U.S.: Trends in the frequency of cyclonic disturbances
174 and their intensification over Indian Seas. Mausam 51, 113–118 (2000)
175 11. Sikka, D.R.: Major advances in understanding and prediction of tropical cyclones over the
176 north Indian Ocean: a perspective. Mausam 57, 165–196 (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), 53–58 (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, 243–248
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, 157–163
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)
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