Monthly zonification of surface biophysical features of Gulf of Mexico using a dynamic classification approach of satellite derived information

Abigail Uribe1, Raul Aguirre-Gomez1, Rainer Ressl2, Eduardo Cuevas-Flores3 and Jorge Zavala-Hidalgo4, (1)Posgrado en Geografía, Universidad Nacional Autónoma de México., Facultad de Filosofía y Letras., Mexico, D.F., Mexico, (2)National Commission for Knowledge and Use of Biodiversity, Geomatics, Mexico City, Mexico, (3)CINVESTAV, Laboratorio de Percepción Remota y SIG, Merida, Yuc., Mexico, (4)Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
The Gulf of Mexico (GoM) is a partially isolated sea with oceanographic features typified by biophysical attributes that influence complex environmental process in the region. It is one of the Large Marine Ecosystems of the world, which main force is the intensive fishing and heavy oil production. The main inflow into the GoM is provided by the Yucatan Current, a warm water current that flows from Caribbean Sea in a northward direction. It forms the loop current which represents the main circulation feature in the Gulf of Mexico. The GoM also has the influence of several river discharges and other coastal aspects. The form and extension of all these features varies strongly across the year. The objective of this study was to delimit superficial marine zones with distinctive oceanographic characteristics in the area. Monthly climatologies (2003 - 2013) of Sea Surface Temperature (SST), Chlorophyll-a (CHLO-a), Chlorophyll Fluorescence (FLH), Absolute dynamic topography (ADT), surface winds (SWds) and geostrophic currents (GC) were analyzed, using a semisupervised classification approach in order to obtain biophysical zones throughout the year. Fourteen different superficial zones were differentiated. Monthly differences in observed zones extension were detected, which are evidence of intra annual variability. The biggest zone observed was the North of GoM, characterized by SST and ADT lower than the rest; it becomes bigger during winter and narrower during summer. The Yucatan and Lazo Currents were divided in 2 different zones each, defined by their velocity and direction. The former zones get larger during summer months, while the latter change along the year. The coast of Mexico showed 4 and 5 zones; they are characterized by their biological attributes, and they change in form and extension or even disappear throughout the year. The central area of GoM is differentiated by eddies detached from Lazo Current. It is also possible to distinct the Florida Current, two different Caribbean zones and two Atlantic zones. This study contributes with a distinct methodological approach, and it is a basis for future analyses to recognize spatial inter annual variations.