Predicting Lake Erie Wave Heights using XGBoost

Dangerous large wave put the coastal communities and vessels operating under threats and wave predictions are strongly needed for early warnings. While numerical wave models, such as WAVEWATCH III (WW3), are useful to provide spatially continuous information to supplement in situ observations, however, they often require intensive computational costs. An attractive alternative is machine-learning method, which can potentially provide comparable performance of numerical wave models but only requires a small fraction of computational costs. In this study, we applied and tested a novel machine learning method based on XGBoost for predicting waves in Lake Erie in 2016-2017. In this study, buoy data from 1994 to 2017 were processed for model training and testing. We trained the model with data from 1994-2015, then used the trained model to predict 2016 and 2017 wave features. The mean absolute error of wave height is about 0.11-0.18 m and the maximum error is 1.14-1.95 m, depending on location and year. For comparison, an unstructured WW3 model was implemented in Lake Erie for simulating wind generated waves. The WW3 results were compared with buoy data from National Data Buoy Center in Lake Erie, the mean absolute error of wave height is about 0.12-0.48 m and the maximum error is about 1.03-2.93 m. The results show that WW3 underestimates wave height spikes during strong wind events and The XGBoost improves prediction on wave height spikes. The XGBoost runs much faster than WW3. For a model year run on a supercomputer, WW3 needs 12 hours with 60 CPUs while XGBoost needs only 10 minutes with 1 CPU. In summary, the XGBoost provided comparable performance for our simulations in Lake Erie wave height and the computational time required was about 0.02 % of the numerical simulations.