## 3 Results
### Adjusting the Algorithm to Regional Properties  
#### 3.3.1 Dynamic Properties  
In the vicinity of \(32^{\circ}\)N, water from the California Current (CC) converges with an intrusion of water from the Central North Pacific [27]; thus, the CC turns toward the shore and part of it veers north to incorporate into the Southern California Eddy and the Southern California Countercurrent, while the remainder continues southward along the Baja California coast [28]. Therefore, this convergence forms a persistent feature called the Ensenada Front, an ecological transition zone [27] marked by a strong gradient in Chlorophyll-\(a\) concentration. In the Ensenada Front, the entropic waters of the CC end abruptly, possibly due to the subduction of this pigment and nutrient-rich waters to the southwest [28]. The Ensenada Front separates the CC region [28; 29] into a northern mesotrophic area which has been studied by the CalCOFI project, and a southern oligotrophic area studied by the IMECOCAL project. As depicted in Figure 3, the CalCOFI 2 algorithm's performance underscores the need for distinct algorithms for these areas given the notably different bio-optical properties.  
The southernmost part of the CCS, adjacent to the Baja California Peninsula, serves as a transitional zone where cold water from the subarctic meets warmer water coming from the tropics and subtropics [14; 15]. The location of this transitional zone fluctuates seasonally [14], influencing the state of the oceanic ecosystem because of mixing circulation and water masses, and convergence modulates the biological and chemical processes [16; 17]. Previous studies [14; 17] have identified two distinct provinces separated at around \(28^{\circ}\)N at Punta Eugenia (Figure 1). North of Punta Eugenia, there are subarctic waters throughout most of the year, with year-round upwelling that is most intense during spring and early summer [15]. In the southern region, coastal upwelling occurs mainly in spring and summer, while the tropical and subtropical influences are limited to summer and fall. Also, there are two cyclonic gyres north and south of Punta Eugenia [14]. Ref. [15] suggested that the separation in provinces is due to the change of sign in the wind stress curl at that  
Figure 3: Regional (red circles, Equation (7)) and OCx (blue squares) algorithm retrievals applied to remotely sensed reflectance data (\(\text{F}=\text{log}_{10}[\mathfrak{N}]\), Equation (2)) off the coast of Baja California compared to the log10 of in situ Chl-\(a\) data (gray dots).  
latitude. This interruption in circulation has consequences for the biological properties of the area. Just as the Ensenada Front separates regions with markedly different bio-optical properties, this other dynamic boundary could have the same effect. Therefore, the dataset was separated to determine if these differences would yield an improvement in the mChl-_a_ retrievals. The southern province includes lines 123 to 137 and the northern province includes lines 97 to 120, that is, north of Punta Eugenia (Figure 1). Despite expectations of differences in the distribution or values of \(\mathfrak{R}\) or mChl-_a_, the data dispersion was similar across both provinces, and the polynomials fitted were very similar to the regional algorithm proposed. Variance in mChl-_a_ over the northern province was \(1.2583\left(\text{mg}\;\text{m}^{-3}\right)^{2}\), while in the southern province it was \(1.1840\left(\text{mg}\;\text{m}^{-3}\right)^{2}\), with no statistical difference between the two areas.