CSIR-National Institute of Oceanography Dona Paula, Goa ADB TA 46460-001 IND: Climate-Resilient Coastal Protection and Management Project 17 Aug 2017, New Delhi CLIMATE CHANGE AND IMPACTS ON INDIAN COAST – WAVES & SEA LEVEL JAYA KUMAR SEELAM MANI MURALI .R Principal Scientist, Senior Scientist, CSIR - National Institute of Oceanography CSIR - National Institute of Oceanography Dona Paula, Goa 403004, India Dona Paula, Goa 403004, India Email: jay@nio.org Email: mmurali@nio.org GEF www.nio.org MoWR GR&RM CWC
OBJECTIVE To provide wave climate & sea level changes along the coast of India Trends-Extreme Trends-HC Trends-Medium Time series-HC www.nio.org CLIMATE CHANGE AND IMPACTS ON INDIAN COAST – WAVES & SEA LEVEL
SCOPE i) To make use of the available historic wave data to estimate return periods and to calculate historic trends of wave heights. ii) To estimate projections for wave heights due to climate change. iii) To analyse the historic sea levels data, estimate trends during historical (tide gauge data) and recent periods (satellite altimetry). www.nio.org
METHODS – WAVES Compilation/modelling of historical wave data Hindcast waves 46 Years (1970-2015) Simulation of future wave climate Future medium CC scenario – 7% increase in winds Future extreme CC scenario – 11% increase in winds Analysis of wave data Joint distribution (Hs; Tm; Dir) Return period estimates (Hs: 1 in10,50&100) Trends (Annual maxima, mean & 90 th percentile) www.nio.org
WAVES SIMULATIONS & OUTPUT Hindcast wave simulations 46 (1970-2015) CC wave simulations 92 46 7% increase in winds 46 11% increase in winds Main land Locations 100 Island locations 100 Wave Parameters 3 JD (tables); EVA (3); Trends 3 www.nio.org
MODEL & DOMAIN Hindcast wave climate NCEP/NCAR Reanalysis wind data MIKE-SW Wave climate (1970-2015) Study Area Simulation region: The Indian Ocean 60°S to 30°N and 20°E to 115°E www.nio.org
DATA USED Bathymetry: ETOPO1&2; MIKE-CMAP; NHO charts Wind data (hindcast) : NCEP/NCAR Reanalysis Wave Data : Moored buoys (INCOIS/NIO/NIOT) www.nio.org
HISTORICAL WAVE DATA Hindcast wave data: 46 years (1970 – 2015) NCEP/NCAR Reanalysis Winds (2.5°x2.5°) Model results compared with: • Different input winds: CFSR (0.205°x0.205°) [19 yrs] ECMWF (NIOT wave atlas) [varying spatial resolution] • Measured WRB data: Offshore buoy locations (INCOIS) Nearshore buoy locations (CSIR-NIO) www.nio.org
WAVE RIDER BUOY LOCATIONS www.nio.org
MODEL VALIDATION FOR WEST COAST – AD06 WATER DEPTH ~ 1000 m www.nio.org
MODEL VALIDATION FOR WEST COAST – DS02 WATER DEPTH ~ 800 m www.nio.org
MODEL VALIDATION FOR WEST COAST – SW02 WATER DEPTH ~ 1000 m www.nio.org
MODEL VALIDATION FOR WEST COAST – KARWAR WATER DEPTH = 15 m Amrutha et al, 2016 www.nio.org
MODEL VALIDATION FOR EAST COAST – OB07 WATER DEPTH ~ 200 m www.nio.org
MODEL VALIDATION FOR EAST COAST – BD11 WATER DEPTH ~ 1000 m www.nio.org
MODEL VALIDATION FOR EAST COAST – PARADIP WATER DEPTH ~ 30 m www.nio.org
MODEL VALIDATION FOR EAST COAST – PONDY WATER DEPTH ~ 30 m www.nio.org
ANALYSIS OF WAVES OFF PONDY Estimation of Return Periods - Comparison HINDCAST HINDCAST HINDCAST WEIBULL-3 (NIOT Analysis) WEIBULL-3 (NIO Analysis) WEIBULL-3 (Sanctuary Beach report) 1 3.6 1 1 3.6 5 4.3 5 3.68 5 3.99 10 4.6 10 3.88 10 4.16 25 5.1 25 4.15 25 4.37 50 5.4 50 4.35 50 4.54 100 5.7 100 4.56 100 4.7 www.nio.org
WAVE PARAMETERS Significant wave height, Hs (m) Mean wave period, Tm (s) Mean wave direction, (°) www.nio.org
LOCATIONS ALONG MAINLAND COAST WEST EAST @20m water depth @~50 km spacing Hs, Tm, www.nio.org
LOCATIONS ALONG ISLAND COASTS Andaman & Nicobar Islands Lakshadweep Islands @200m water depth @~50 km spacing Hs, Tm, www.nio.org
ANALYSIS OF WAVES Simulations Parameters Locations Significant wave height, Hs (m) West coast : 50 Hindcast Mean wave period, Tm (s) East coast : 50 Mean wave direction, (°) Medium CC Lakshadweep : 56 Extreme CC Andamans : 44 OUTPUT A. JOINT DISTRIBUTION OF WAVE PARAMETERS (Hs vs Tm; Hs vs ) B. EXTREME VALUE ANALYSIS C. TRENDS OF WAVE HEIGHTS www.nio.org
ANALYSIS OF WAVES Joint Distribution Significant wave height, Hs (m) Mean wave period, Tm (s) Mean wave direction, (°) Hs/Tm 0--2 2--4 4--6 6--8 8--10 10--12 12--14 14--16 16--18 18--20 Total 0.0-0.5 0.04 0.04 6.39 14.74 0.01 0.00 0.00 0.00 0.00 0.00 21.23 0.5-1.0 0.00 0.00 0.36 43.54 6.52 0.02 0.00 0.00 0.00 0.00 50.44 1.0-1.5 0.00 0.00 0.00 11.75 5.89 0.13 0.00 0.00 0.00 0.00 17.77 1.5-2.0 0.00 0.00 0.00 0.07 9.85 0.02 0.00 0.00 0.00 0.00 9.94 2.0-2.5 0.00 0.00 0.00 0.00 0.61 0.01 0.00 0.00 0.00 0.00 0.62 Total 0.04 0.04 6.75 70.10 22.88 0.18 0.00 0.00 0.00 0.00 100.0 0 Hs/Dir 22.5 45 67.5 90 112.5 135 157.5 180 202.5 225 247.5 270 292.5 315 337.5 360 Total 0-0.5 0.04 0.03 0.03 0.06 0.1 0.18 0.24 0.26 0.55 2.23 2.9 2.39 2.85 1.12 0.15 0.05 13.16 0.5-1.0 0.02 0.02 0.03 0.05 0.09 0.16 0.2 0.27 0.64 7.18 14.77 15.41 10.25 4.51 0.32 0.04 53.94 1.0-1.5 0 0 0 0 0 0 0 0.01 0.03 0.22 3.71 7.43 0.87 0.23 0 0 12.5 1.5-2.0 0 0 0 0 0 0 0 0 0.01 0.03 1.07 9.67 0.01 0 0 0 10.79 2.0-2.5 0 0 0 0 0 0 0 0 0 0.01 0.4 6.24 0 0 0 0 6.65 2.5-3.0 0 0 0 0 0 0 0 0 0 0 0.16 2.24 0 0 0 0 2.4 3.0-3.5 0 0 0 0 0 0 0 0 0 0 0.03 0.41 0 0 0 0 0.44 3.5-4.0 0 0 0 0 0 0 0 0 0 0 0.01 0.09 0 0 0 0 0.1 4.0-4.5 0 0 0 0 0 0 0 0 0 0 0.01 0.01 0 0 0 0 0.02 9.5-10.0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Total 0.06 0.05 0.07 0.11 0.18 0.34 0.44 0.54 1.23 9.66 23.06 43.89 13.98 5.85 0.47 0.08 100 www.nio.org
ANALYSIS OF WAVES Extreme Value Analysis Extreme Value Analysis of Significant Wave height, Hs Scenario 1 - 1: 5,10,25,50,100 (Hindcast) Scenario 2 - 1: 5,10,25,50,100 (+Av CC = 7% increase in winds) Scenario 3 - 1: 5,10,25,50,100 (+Max CC = 11% increase in winds) Distribution methods Weibull-2; Weibull-3; Generalised Pareto www.nio.org
ANALYSIS OF WAVES Estimation of Return Periods – P30 HINDCAST/ WEIBULL-2 WEIBULL-3 GP RETURN PERIOD 1 3.89 4.49 4.42 5 4.26 5.03 4.6 10 4.41 5.26 4.66 15 4.49 5.39 4.69 25 4.6 5.55 4.72 50 4.74 5.77 4.76 100 4.88 5.99 4.79 www.nio.org
ANALYSIS OF WAVES Estimation of Return Periods OD WB TN AP GA KL GJ MH KA TN AP OD WB GA GJ MH KA KL OD WB TN AP GA KL GJ MH KA
ANALYSIS OF WAVES Estimation of Return Periods State Min/Max Hindcast Medium CC Extreme CC Gujarat Min 2.98 3.28 3.46 Max 7.44 8.67 9.41 Maharashtra Min 4.17 4.62 4.88 Max 7.08 8.18 8.77 Goa Min 5.81 6.52 6.86 Max 6.65 7.64 8.18 Karnataka Min 5.58 6.29 6.68 Max 6.08 6.93 7.39 Kerala Min 4.16 4.71 4.98 Max 4.73 5.31 5.63 Tamil Nadu Min 3.53 3.85 4.07 Max 3.86 4.28 4.63 Andhra Pradesh Min 3.71 4.03 4.28 Max 4.15 4.67 4.96 Odisha Min 4.3 4.85 5.15 Max 5.41 5.86 6.19 West Bengal Min 4.77 5.34 5.66 Max 5.15 5.83 6.2 Lakshadweep Min 3.85 4.2 4.55 Max 9.04 10.46 11.24 Andaman & Min 4.16 4.44 4.77 Nicobar Max 7.53 8.49 9.14 www.nio.org
ANALYSIS OF WAVES Trends Hindcast Annual maxima AVG CC EXTREME CC Annual mean Y = mX + C 90 th percentile Slope term = trend (m/yr) (as in Shanas et al., 2015) www.nio.org
ANALYSIS OF WAVES Estimation of Trends OD WB TN AP GA KL GJ MH KA www.nio.org
ANALYSIS OF WAVES Estimation of Trends (cm/yr) Hindcast Medium CC Extreme CC Min Max Min Max Min Max Annual Mean Hs for mainland west coast -0.087 0.186 -0.093 0.196 -0.126 0.173 Annual Hs Maxima for mainland west coast -1.015 0.199 -1.029 0.219 -1.112 0.195 Annual Mean Hs for mainland east coast -0.143 0.166 -0.167 0.175 -0.203 0.152 Annual Hs Maxima for mainland east coast -0.487 0.458 -0.508 0.469 -0.524 0.421 Annual Mean Hs for Lakshadweep -0.190 0.610 -0.270 0.870 -0.370 0.540 Annual Hs Maxima for Lakshadweep -1.000 0.890 -1.400 1.700 -1.500 0.600 Annual Mean Hs for Andaman 0.120 0.760 0.000 0.420 -0.018 0.410 Annual Hs Maxima for Andaman -1.400 0.600 -1.600 0.450 -1.800 0.370 www.nio.org
SUMMARY Simulated hindcast wave data 46 years (1970-2015) Simulated wave data – medium & extreme CC 46 years Analysis of wave parameters: Joint distributions of Hs, Tm and MWD Return period for Hs 1:5,10,15,25,50&100 years Trend analysis with annual maxima, mean and 90 th percentile Data analysis complete-report complete & submitted www.nio.org
SUMMARY An increase in wave heights up to 16.53% for medium CC case and up to 26.48% for extreme CC condition is observed (compared to hindcast waves). The wave height trends along the Indian coast can have a range between -1.4 cm/yr to 0.89 cm/yr from the hindcast study; -1.6 to 1.7 for medium CC case and -1.8 to 0.6 for extreme CC case. www.nio.org
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