TITLE:
The Influence of Large-Scale Phenomena on La Paz Bay Hydrographic Variability
AUTHORS:
Cristóbal Guevara-Guillén, Bernardo Shirasago-Germán, Edgar Leonardo Pérez-Lezama
KEYWORDS:
Pacific Large-Scale Phenomena, La Paz Bay, Gulf of California, Hydrography, Annual Patterns
JOURNAL NAME:
Open Journal of Marine Science,
Vol.5 No.1,
January
27,
2015
ABSTRACT: We analyzed the hydrographic
variability of La Paz Bay, the largest coastal water body in the Gulf of
California, and its relationship with Pacific large-scale phenomena, including
the El Ni?o-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO),
Pacific-North America pattern (PNA), and North Pacific pattern (NP). We used
several indices related to these phenomena and the hydrographic variability
data of La Paz Bay, consisting of the annual sea surface temperature patterns
from satellite imagery from 2000 to 2010 and the mixed layer depths measured
within situdata from 1994 to 2009. The results indicate the
sea surface temperature fluctuated during the study period, with 2007 as the
coldest year and 2009 as the warmest. Two periods were identified in the annual
thermal cycle of the bay, one period of warmth from June to November, and one
of cold from December to May. The sea surface temperature is primarily
influenced by the ENSO. The mixed layer depth analysis showed its absence
during August-September, while the deepest ones were in November-March. The
unusual 100 m mixed layer depth noted during February 2002 and its absence in
March 1996 and 2009 were related to uncommon atmospheric conditions in the
annual patterns of the ENSO, PNA, and NP. The variability of the mixed layer
depth is primarily related to the variability of the NP. We concluded that the
hydrographic conditions of La Paz Bay are most influenced by the NP during the
cold phase of its annual cycle, and by the ENSO during the warm phase.