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Forecasting impact of climate change on WELCOME TO THE SECOND AIACC runoff coefficient in Limpopo basin using ANN WORKSHOP, DAKAR AF_42 RESEARCH TEAM BOTSWANA MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecastingimpact impact of change on on Forecasting ofclimate climate change runoff coefficient in Limpopo basin using ANN runoff coefficients in Limpopo basin using Artificial Neural Network presenter: Prof. B.P. Parida UniversityAF_42 of Botswana, MARCH 24 -27, 2004 DAKAR WORKSHOPGaborone Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Area : 80 000 km2 ~ 1/8 area of Botswana 4 Dams: 350 M Cum. Farm Land : ~ Food Security MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Multi-cell representation The Limpopo Basin MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Year Run off Coeff 1971 0.40 1972 0.29 1973 0.47 1974 0.46 1975 0.37 1976 0.56 1977 0.35 1978 0.21 1979 0.48 MARCH 24 -27, 2004 1980 0.37 Year Run off Coeff 1981 0.35 1982 0.38 1983 0.35 1984 0.34 1985 0.48 1986 0.40 1987 0.52 1988 0.38 1989 0.36 AF_42 DAKAR WORKSHOP 1990 0.56 Year Run off Coeff 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 0.39 0.35 0.50 0.43 0.60 0.55 0.59 0.43 0.40 0.45 Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Why runoff coefficient (roc) ? Rainfall ~ Runoff complex roc = (total runoff) / (total rainfall) Assumed to marginalize the impact of land use changes decrease in rainfall ~ increase in roc decrease in roc ~ decrease in flow MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Source: Hydrological Sciences Journal MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Dendrides Cell body Axon Nucleus Axons Nucleus Dendrites MARCH 24 -27, 2004 Sunapses AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Biological Neuron - specific type of cell - provides cognitive and other related activities. - Neuron collects signals from dendrites - Spikes of electrical activity sent out by a neuron through – long thin strands – axon which is split into thousands of branches - At the end of each branch – synapse, which converts the activity from axon into electrical effects that excite activity. ( changing effectiveness of synapse, influence from preceding neuron is influenced) MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Artificial Neuron – simulates the four basic components as well as functioning of the natural neuron. - Each neuron receives output from many other neurons through input path. - Each of the inputs to a neuron is multiplied by a weight. - Products are then summed up and fed through a transfer function to generate an output. MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Xo Wo W1 X1 Sum W2 Transf er X2 Output path W3 X3 . . . Processing element W4 Xn Inputs Xn Weights W n The basic structural functioni ng of a neuron MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN First and hidden layer Input neurons Output layer neuron Input array Output array MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Output of the best minimized performance function adopted for the study MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN T = TARGET A = ACHIEVEMENT Regression between target and modelled runoff coeffs MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Conf. Levl MSE PCs used 2.5 Quantity value 2 1.5 1 0.5 0 1 2 3 4 5 6 Quantity optimized MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP 7 8 Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Target and simulated runoff coefficients plotted for the entire study period MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Input variables used: Annual Rainfall and Annual Evaporation Target /Output variable: Water balance computed runoff coefficients. Training Algorithms Used: Automated regularization with early stopping (as it outclassed others) Transfer functions used: Log-sigmoid for hidden layer and purelin for the output layer. The optimum number of neurons in the hidden layer: Fifteen Final Choice of Architecture: Was arrived using PCA, was also found to be the best with two components used and at 0.001 significance level. For Forecasting/Prediction: Model Predictive Control MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Simulations up to year 2000 & Forecasts into the year 2016 MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Runoff Coefficients 0.70 0.60 0.50 By Extrpolation 0.40 Excel Toolbox 0.30 By ANN 0.20 …. 0.10 20 15 20 13 20 11 20 09 20 07 20 05 20 03 20 01 0.00 Year A comparison between the forecasted runoff co-efficient obtained from ANN, EXCEL Tool Box & Extrapolation. MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN y = 0.0035x + 0.4908 0.70 y = 0.0004x + 0.4833 y = -0.0006x + 0.4468 0.60 0.50 By Extrapolation 0.40 Using ANN 0.30 Using Excel Tool Box 0.20 0.10 0.00 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Comparison of Trend in Runoff Coefficints. MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Period 1971 - 1980 : 1981 - 1990 : 1991 - 2000 : 2001 - 2010 : 2001 - 2016 : MARCH 24 -27, 2004 Avg. ROC 0.40 0.41 (2.5%) 0.47 (14.6%) 0.48 (2.13%) 0.50 (4.2%) AF_42 DAKAR WORKSHOP % increase per year 9 4.7 6.1 4.7 3.8 Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN In conclusion: It is evident that the by the next two decades runoff is likely to decrease so a good water management strategy will be necessary as a possible adaptation measure. MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP Forecasting impact of climate change on runoff coefficient in Limpopo basin using ANN Thank You for listening MARCH 24 -27, 2004 AF_42 DAKAR WORKSHOP