Sea Surface Temperature (SST) Variability of the Eastern Coastal Zone of the Gulf of California

Carlos Robles-Tamayo,Luis Enríquez-Ocaña,José Valdez-Holguín,Gudelia Figueroa-Preciado,Ricardo García-Morales,Hugo Herrera-Cervantes,Juana López-Martínez

doi:10.3390/rs10091434

Abstract

The coastal zones are areas with a high flow of energy and materials where diverse ecosystems are developed. The study of coastal oceanography is important to understand the variability of these ecosystems and determine their role in biogeochemical cycles and climate change. Sea surface temperature (SST) analysis is indispensable for the characterization of physical and biological processes, and it is affected by processes at diverse timescales. The purpose of this work is to analyze the oceanographic variability of the Eastern Coastal Zone of the Gulf of California through the study of the SST from time series analysis of monthly data obtained from remote sensors (AVHRR-Pathfinder Version 5.1 and Version 5 resolution of 4 km, MODIS-Aqua, resolution of 4 km) for the period 1981 to 2016. The descriptive analysis of SST series showed that the values decrease from south to north, as well as the amplitude of the warm period decrease from south to north (cold period increase from south to north). The minimum values occurred during January and February, and ranged between 18 and 20 °C; and maximum values, of about 32 °C, arose in August and September. Cluster analysis allowed to group the data in four regions (south, center, midriff islands and north), the spectral analysis in each region showed frequencies of variation in scales: Annual (the main), seasonal, semiannual, and interannual. The latter is associated with the El Niño and La Niña climatological phenomena.

Highlights

The coastal zones are wide geographical areas with intense physical, chemical and biological interactions with strong exchange of energy and materials between the terrestrial environment, aquatic environment and the atmosphere [1]
The Gulf of California is a marginal sea located in the Eastern Pacific Ocean, surrounded by arid environment that encompasses the Baja California Peninsula, and the states of Sonora, Sinaloa, and Nayarit, with an average length and width of 1400 and 150–200 km respectively and basins separated by sills [4,5]
Two well defined periods were observed in the annual Sea surface temperature (SST) pattern for the Eastern Coast of the Gulf of California: Warm period with SST higher than 25 ◦C, and cold period with SST lower than 25 ◦C, May–June and November are transitions periods with temperatures around the 25 ◦C (Figure 3)

Summary

Introduction

The coastal zones are wide geographical areas with intense physical, chemical and biological interactions with strong exchange of energy and materials between the terrestrial environment, aquatic environment and the atmosphere [1]. The coastal zones have high primary productivity levels and play important role in the biogeochemical cycles [2]. These areas support high abundance of natural resources, providing refuge, feeding and spawning areas for diverse organisms, and enhancing activities like tourism, aquaculture and fisheries [3]. Northwest Winds from December to May produce intense upwelling processes off the Eastern Coast. During these “winter conditions”, nutrients supply enhance the growth of phytoplankton communities. The Baja California Peninsula has mountain ranges that prevent the low-level clouds from the Pacific Ocean influencing in the gulf generating cloud-free most of the time with exceptions in summer when the tropical air from the south moves into the gulf [8]

Objectives

Methods

Results

Conclusion