Over the past decade (2002–2013) the Bay of Bengal has experienced 12 cyclones and 27 tropical storms. The recent

one was the cyclone Phailin which was equivalent to a category-5 hurricane on the Saffir–Simpson hurricane wind scale(SSHWS). The cyclonic storm developed over the north of Andaman and Nicobar Islands on 9 October 2013. Subsequen

tly,it propagated towards north-northwest and made a landfall at the Gopalpur coast of south Odisha on 12 October

Kumar, TS

Lotliker, AA

Nayak, S

Reddem, VS

Ministry of Earth Sciences, Government of India

SCIENTIFIC CORRESPONDENCE 
 
CURRENT SCIENCE, VOL. 106, NO. 3, 10 FEBRUARY 2014 360 
Cyclone Phailin enhanced the productivity following its passage: 
evidence from satellite data 
 
Over the past decade (2002–2013) the 
Bay of Bengal has experienced 12 cyclo-
nes and 27 tropical storms. The recent 
one was the cyclone Phailin which was 
equivalent to a category-5 hurricane on 
the Saffir–Simpson hurricane wind scale 
(SSHWS). The cyclonic storm developed 
over the north of Andaman and Nicobar 
Islands on 9 October 2013. Subsequently, 
it propagated towards north-northwest 
and made a landfall at the Gopalpur coast 
of south Odisha on 12 October. Although 
the cyclone sustained in the ocean for a 
short span of four days, an elevated con-
centration of chlorophyll a (Chl a) and 
decrease in sea-surface temperature (SST) 
were observed along the cyclone track in 
Moderate Resolution Imaging Spectrora-
diometer (MODISA) images (Figure 1). 
The strong cyclonic winds often result in 
the mixing of surface water layer to the 
greater depths. This introduces nutrients 
to the mixed layer and result in increase 
in Chl a and decrease in SST, thus  
enhancing the productivity of the water 
column1. We studied the case further to 
quantify the increase in Chl a and de-
crease in SST due to the cyclone Phailin. 
 The entire track of the cyclone was  
divided into four sectors (B1–B4, Figure 
1) based on the difference coerced on 
each day. Further, 12 years of MODISA 
L1A data for the period 1–17 October 
were processed for each sector to gener-
ate Chl a and SST. Subsequently, Chl a 
and SST climatology was generated us-
ing the data for the years from 2002 to 
2012 (solid line, Figure 2). The accuracy 
of Chl a and SST products, generated 
from MODISA, in oligotrophic open 
ocean waters has been well documented. 
The SST derived from MODISA is com-
parable in accuracy to that derived by  
Advance Very High Resolution Radi-
ometer (AVHRR)2 whereas the Chl a re-
trieved from MODISA has an estimated 
error of maximum 25% in oligotrophic 
waters3. However, OC3M algorithm pro-
duces better estimates of Chl a from 
MODISA in Indian coastal waters, with 
an estimated error of 11% (ref. 4). 
 This correspondence reports two dimen-
sions of analysis. The first is to quantify 
pre- and post-cyclonic changes in Chl a 
and SST. The second is to address the 
anomalies in Chl a and SST with respect 
to climatology. The temporal variability 
in Chl a and SST was almost followed 
the climatology in all four sectors prior 
to the cyclone (Figure 2). In sector B1, 
where the cyclone passed on 9 October, 
the peak Chl a (0.65 mg m–3) and mini-
mum SST (28.46C) were observed on 
12 October. With reference to pre-
cyclonic condition, Chl a increased  
by 295% with a positive anomaly of 
0.51 mg m–3. The SST decreased by 
0.3C compared to pre-cyclonic condi-
tion, with a negative anomaly of 0.6C. 
Subsequently, after 14 October the sys-
tem was stable with both Chl a and SST 
close to climatology. The cyclone passed 
sector B2 on 10 October. Subsequently, 
an increase in Chl a and decrease in SST 
were observed. The peak Chl a (0.69 mg 
m–3) and minimum SST were observed 
on 15 and 13 October respectively. The 
Chl a peaked to 0.51 mg m–3, whereas 
the SST decreased to 28.7C. The post-
cyclonic condition showed 250% increase 
in Chl a and 0.41C decrease in SST. 
Further, Chl a showed positive anomaly 
of 0.38 mg m–3 and SST showed a nega-
tive anomaly of 1.0C. After 15 October 
the system moved towards equilibrium, 
showing values similar to climatology. In 
sector B3, peak Chl a (0.69 mg m–3) and 
minimum SST (27.3C) were seen on 15 
October with an anomaly of 0.5 mg m–3  
in Chl a. Also, this sector showed
 
 
 
 
Figure 1. Spatial distribution of MODISA-derived chlorophyll a (Chl a) and sea-surface temperature (SST) after passage 
of the cyclone Phailin. The extremely left panel shows Chl a and SST climatology for the month of October overlaid with 
the cyclone track. 
SCIENTIFIC CORRESPONDENCE 
 
CURRENT SCIENCE, VOL. 106, NO. 3, 10 FEBRUARY 2014 361 
 
 
Figure 2. Time-series variability of spatially averaged Chl a and SST from MODISA in four sectors (B1–B4). The solid line is for 11 
years climatology (2002–2012). The dots represent data corresponding to the year 2013. The vertical bar indicates passage of the cyclone. 
 
 
maximum negative anomaly in SST 
(2.4C). Further, Chl a increased up to 
144% and SST decreased up to 2.4C 
compared to pre-cyclonic condition. The 
variability of Chl a and SST in sector B4 
was most dynamic. This sector experi-
enced a combined effect of cyclone as 
well as coastal processes. Although the 
cyclone crossed B4 on 12 October, the 
precipitation was initiated much earlier.  
This must have resulted in positive ano-
maly in Chl a and negative anomaly in 
SST prior to landfall. Subsequent to 
landfall, Chl a peaked up to 6.16 mg m–3 
and SST decreased up to 27.3C on 17 
and 16 October respectively. The increase 
in Chl a (710%) and decrease in SST 
(2.3C) was compared to pre-cyclonic 
condition. The recorded anomaly for 
Chl a and SST was 4.35 mg m–3 and 
2.5C respectively. 
 The productivity in the Bay of Bengal 
is often low. The strong stratification  
resulted due to large river influx acting 
as a boundary and thus restricting supply 
of nutrients to the surface waters. How-
ever, in northern Bay of Bengal the 
stratification is not strong enough to pre-
vent the upwelling of nutrients. The  
cyclonic circulation thus brings the sub-
surface nutrients that result in increase in 
Chl a, decrease in SST and thus increase 
in productivity1,4. The cyclone-induced 
high productivity has been reported ear-
lier in the Bay of Bengal5,6. In the case of 
cyclone Sidr, a patch of 900 km phyto-
plankton boom was observed along the 
track. Chl a peaked up to 285% with a 
maximum cooling of 3.2C compared to 
pre-cyclonic condition. The shoaling of 
mixed layer to 35 m was also reported 
after the cyclone5. The Odisha super cy-
clone has shown maximum impact on the 
productivity as well as SST. After pas-
sage of this super cyclone, a record  
decrease in SST (6C) was reported7.  
Further, Chl a increased from 1 to 
20 mg m–3, as observed from IRS-P4-
OCM data6. The surface cooling in case 
of cyclone Phailin was less intense com-
pared to the Odisha super cyclone. How-
ever, the changes in Chl a and SST were 
significant, especially in the coastal area 
compared to the cyclone Sidr. 
 
 
 
1. Vinaychandran, P. N. and Mathew, S., 
Geophys. Res. Lett., 2003, 30(11); doi: 
10.1029/2002GL016717. 
2. Minnett, P. J., Evans, R. H., Kearns, E. J. 
and Brown, O. B., IEEE Geosci. Remote 
Sensing, 2002, 2, 1177–1179. 
3. O’Reilly, J. E. et al., In SeaWiFS Post-
launch Technical Report Series, SeaWiFS 
Post- launch Calibration and Validation 
Analyses, Volume 11, Part 3 (eds Hooker, 
S. B. and Firestone, E. R.), NASA God-
dard Space Flight Center, Greenbelt, Mary-
land, 2000, pp. 9–23. 
4. Tilstone, G. H. et al., Continental Shelf  
Res., 2013, 65, 14–26. 
5. Tummala, S. K., Nayak, S. R., Mupparthy, 
R. S. and Kumar, N. M., J. Appl. Remote 
Sensing, 2009, 3(1); doi: 10.1117/ 
1.3238329. 
6. Nayak, S. R., Sarangi, R. K. and Rajawat, 
A. S., Curr. Sci., 2001, 80(9), 1208–1213. 
7. Sadhuram, Y., Curr. Sci., 2004, 86(3), 
383–384. 
 
 
 
ACKNOWLEDGEMENTS. We thank NASA- 
GSFC for MODISA data and NESDIS of 
NOAA Satellite and Information Service for 
cyclone track information. 
 
 
 
Received 31 October 2013; revised accepted 
27 December 2013 
 
ANEESH A. LOTLIKER1 
T. SRINIVASA KUMAR1,* 
VENKAT SHESU REDDEM1 
SHAILESH NAYAK2 
 
1Indian National Centre for Ocean  
 Information Services, Ocean Valley,  
Pragathi Nagar (BO), Nizampet (SO),  
Hyderabad 500 090, India 
2Earth System Science Organization 
(ESSO), ‘Prithvi Bhavan’, 
Lodhi Road,  
New Delhi 110 003, India 
*For correspondence. 
e-mail: srinivas@incois.gov.in 
 
 


Cyclone Phailin enhanced the productivity following its passage: Evidence from satellite data

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Cyclone Phailin enhanced the productivity following its passage: Evidence from satellite data

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