A hybrid model for the forecasting of sea surface water temperature using the information of air temperature: a case study of the Baltic Sea

Figures & data

Figure 1. Study area showing the gauge stations and the corresponding meteorological stations (the numbers and characters are referred to Table 1).

Table 1. The studied gauge stations and the corresponding meteorological stations (Designation according to Figure 1).

No.	Gauge stations	No.	Meteorological station
1	Kołobrzeg	A	Kołobrzeg
2	Łeba	B	Łeba
3	Władysławowo	C	Hel
4	Hel	C	Hel
5	Puck	C	Hel
6	Gdynia	C	Hel

Figure 2. Time series data of daily sea surface temperature (SST) and air temperature (Ta) for the six studied stations: (1) Kołobrzeg, (2) Łeba, (3) Władysławowo, (4) Hel, (5) Puck, and (6) Gdynia.

Figure 2. (Continued).

Figure 3. Trend analysis of annual average sea surface temperature (SST) and air temperature (Ta) for the six studied stations: (1) Kołobrzeg, (2) Łeba, (3) Władysławowo, (4) Hel, (5) Puck, and (6) Gdynia.

Table 2. Summary of the parameter values for the studied stations.

Station	Parameters
	a1	a2	a3	a4	a5	a6	a7	a8
	(°C d^−1)	(d^−1)	(d^−1)	(°C)	(°C d^−1)	(-)	(-)	(-)
1	0.342	0.040	0.077	17.381	0.288	0.569	142.432	0.493
2	0.412	0.051	0.092	6.294	0.424	0.538	3.466	0.000
3	0.459	0.051	0.098	17.435	0.364	0.566	6.733	0.498
4	0.294	0.051	0.077	7.950	0.218	0.626	12.116	0.000
5	0.149	0.051	0.060	7.441	0.171	0.457	6.267	0.000
6	0.169	0.051	0.063	10.296	0.120	0.560	6.870	0.478

Figure 4. Box plots showing the modelled and observed sea surface temperature (SST) values for the validation period (2017–2019) at the six studied stations: (1) Kołobrzeg, (2) Łeba, (3) Władysławowo, (4) Hel, (5) Puck, and (6) Gdynia.

Figure 4. (Continued).

Table 3. Summary of the modelling results for the studied stations.

Station	Calibration		Validation
	RMSE	NSE	RMSE	NSE
1	1.314	0.953	1.703	0.920
2	1.546	0.950	1.614	0.948
3	1.325	0.954	1.286	0.959
4	0.895	0.980	0.874	0.981
5	1.038	0.980	0.991	0.982
6	1.013	0.977	0.999	0.978

Figure 5. RMSE values for each year (Yearly) and warm period (June–September) at the six studied stations: (1) Kołobrzeg, (2) Łeba, (3) Władysławowo, (4) Hel, (5) Puck, and (6) Gdynia.

Data Availability Statement

The data used in this study are available upon request from the corresponding author. https://github.com/slzhu1989?tab=repositories