The application performance of the ANN model in the ECS shelf

In order to retrieve pH on the ECS shelf, the monthly T, S, DO, N, P and Si from the Changjiang Biology Finite-Volume Coastal Ocean Model (FVCOM) Data were applied to the ANN model as the input variables. Monthly pH for the period 2000-2016 was obtained at the spatial resolution of the Changjiang Biology FVCOM output: 1-10 165 km in the horizontal, 10 depth levels in the vertical, and 12 months. We compared retrieved pH with the corresponding observations at some sites repeated sampling for 3 to 4 years in order to evaluate the application performance of the ANN model. These sites were A1-5 (123.0140°E, 32.2145°N), A1-6 (123.2750°E, 32.2679°N), A6-7 (122.9880°E, 30.7050°N), A6-9 (123.4990°E, 30.5723°N), A7-5 (123.4990°E, 30.2523°N), and A8-5 (123.4930°E, 29.9940°N). Additionally, we further compared retrieved pH using the Changjiang Biology FVCOM Data with retrieved pH using measured T, S and DO, and in situ measured pH values.