Abstract:
In the present study, artificial neural network technique has been employed to predict
daily rainfall and evaporation for Pattambi, Kerala. The total 6 years (2014-2019)
meteorological data of months June, July, August and September was taken for rainfall
prediction. Similarly for evaporation model 6 years (2014-2019) meteorological data was
taken. Climatic variables namely, maximum temperature, minimum temperature, wind speed,
relative humidity, sunshine hours were taken as input parameters and rainfall and evaporation
were taken as output parameters for prediction. For both rainfall and evaporation prediction
models 75% of the data were used for training and 25% of the data were used for testing.
Statistical data analysis was carried out to identity important climatic variables for developing
ANN model. In this study the MATLAB software was used for ANN model development
having neural network tool with different network architectures, transfer function, learning
functions etc. The networks were developed by using feed forward hack propagation with log
sigmoid and tan sigmoid transfer functions. The performance of the models were evaluated
quantitatively by using different performance indices viz. root mean square error, correlation
coefficient and coefficient of determination. The model with highest value of correlation
coefficient (R) and lowest value of root mean square error (RMSE) is considered as the best
fit model. It was observed that log sigmoid transfer function is capable of predicting the
evaporation and tan sigmoid transfer function is capable of predicting the rainfall with almost
equal prediction efficiency. For evaporation simulation, model 4 is found to be the best fit
model having R and RMSE as 0.5954 and 2.060 respectively. And with normalized data for
evaporation simulation, model 3 is found to be the best fit model having R and RMSE as
0.553 and 2.077 respectively. For rainfall simulation, model 1 is found to be the best fit
model having R and RMSE as 0.544 and 11.132 respectively. These models may be used to
predict daily rainfall and evaporation of Pattambi, Kerela.
