Table 3. Results of Chi-squared test comparing the numbers of upwelling signals detecting with and without SST as a filter across the four data products at four sites.

Comparison	χ2	p	d.f.
All products and sites	141.18	<0.001	1
OISST	15.77	<0.001	3
MUR	14.39	0.002	3
G1SST	20.04	<0.001	3
CMC	20.47	<0.001	3
SACTN	34.11	<0.001	3
Lamberts Bay	108.77	<0.001	4
Port Nolloth	152.45	<0.001	4
Saldanha Bay	90.41	<0.001	4
Sea Point	19.65	<0.001	4