24 research outputs found
Lagrangian dynamical geography of the Gulf of Mexico
We construct a Markov-chain representation of the surface-ocean Lagrangian
dynamics in a region occupied by the Gulf of Mexico (GoM) and adjacent portions
of the Caribbean Sea and North Atlantic using satellite-tracked drifter
trajectory data, the largest collection so far considered. From the analysis of
the eigenvectors of the transition matrix associated with the chain, we
identify almost-invariant attracting sets and their basins of attraction. With
this information we decompose the GoM's geography into weakly dynamically
interacting provinces, which constrain the connectivity between distant
locations within the GoM. Offshore oil exploration, oil spill contingency
planning, and fish larval connectivity assessment are among the many activities
that can benefit from the dynamical information carried in the geography
constructed here.Comment: Submitted to Scientific Report
Comparison of upwelling indices off Baja California derived from three different wind data sources
This report is not copyrighted. The definitive version was published in California Cooperative Oceanic Fisheries Investigations Reports 48 (2007): 204-214.We compared the NOAA Southwest Fisheries Science
Center’s Environmental Research Division (formerly
Pacific Fisheries Environmental Laboratory: PFEL) coastal
upwelling indices along the northern Baja California
coast with those derived from winds measured by coastal
meteorological stations and estimated by the QuikSCAT
satellite. With the exception of the PFEL series at 33°N,
the three data sets compare reasonably well, having similar
typical year patterns, correlations >0.6, and significant
coherences for periods three to five days or longer.
By contrast, the seasonal variations, the timing and magnitude
of maximum upwelling, and the variability of the
PFEL indices at 33°N are significantly different compared
to all the other time series, including QuikSCAT
at that location. The performance of the QuikSCAT
winds close to shore was evaluated using the coastal
meteorological station data. Although large root-meansquare
(RMS) errors in direction were found for the
QuikSCAT winds, both datasets have properties similar
to the variance ellipses, and show reasonable coherences
for frequencies in the weather band and lower, particularly
south of 33°N.This project was partially funded by the U.S. National
Science Foundation through grants to J. P. and M. L
Hydrography of the Gulf of Mexico using autonomous floats
Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 773-794, doi:10.1175/JPO-D-17-0205.1.Fourteen autonomous profiling floats, equipped with CTDs, were deployed in the deep eastern and western basins of the Gulf of Mexico over a four-year interval (July 2011–August 2015), producing a total of 706 casts. This is the first time since the early 1970s that there has been a comprehensive survey of water masses in the deep basins of the Gulf, with better vertical resolution than available from older ship-based surveys. Seven floats had 14-day cycles with parking depths of 1500 m, and the other half from the U.S. Argo program had varying cycle times. Maps of characteristic water masses, including Subtropical Underwater, Antarctic Intermediate Water (AAIW), and North Atlantic Deep Water, showed gradients from east to west, consistent with their sources being within the Loop Current (LC) and the Yucatan Channel waters. Altimeter SSH was used to characterize profiles being in LC or LC eddy water or in cold eddies. The two-layer nature of the deep Gulf shows isotherms being deeper in the warm anticyclonic LC and LC eddies and shallower in the cold cyclones. Mixed layer depths have an average seasonal signal that shows maximum depths (~60 m) in January and a minimum in June–July (~20 m). Basin-mean steric heights from 0–50-m dynamic heights and altimeter SSH show a seasonal range of ~12 cm, with significant interannual variability. The translation of LC eddies across the western basin produces a region of low homogeneous potential vorticity centered over the deepest part of the western basin.The authors were supported by
the Department of the Interior, Bureau of Ocean Energy
Management (BOEM), Contract M08PC20043 to
Leidos, Inc., Raleigh, North Carolina.2018-10-0
Deep eddies in the Gulf of Mexico observed with floats
Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 2703-2719, doi:10.1175/JPO-D-17-0245.1.A new set of deep float trajectory data collected in the Gulf of Mexico from 2011 to 2015 at 1500- and 2500-m depths is analyzed to describe mesoscale processes, with particular attention paid to the western Gulf. Wavelet analysis is used to identify coherent eddies in the float trajectories, leading to a census of the basinwide coherent eddy population and statistics of the eddies’ kinematic properties. The eddy census reveals a new formation region for anticyclones off the Campeche Escarpment, located northwest of the Yucatan Peninsula. These eddies appear to form locally, with no apparent direct connection to the upper layer. Once formed, the eddies drift westward along the northern edge of the Sigsbee Abyssal Gyre, located in the southwestern Gulf of Mexico over the abyssal plain. The formation mechanism and upstream sources for the Campeche Escarpment eddies are explored: the observational data suggest that eddy formation may be linked to the collision of a Loop Current eddy with the western boundary of the Gulf. Specifically, the disintegration of a deep dipole traveling under the Loop Current eddy Kraken, caused by the interaction with the northwestern continental slope, may lead to the acceleration of the abyssal gyre and the boundary current in the Bay of Campeche region.The authors were supported by the
Department of the Interior, Bureau of Ocean Energy
Management (BOEM), Contract M10PC00112 to
Leidos, Inc., Raleigh, North Carolina.2019-05-0
The role of season and salinity in influencing barnacle distributions in two adjacent coastal mangrove lagoons
Author Posting. © University of Miami - Rosenstiel School of Marine and Atmospheric Science, 2011. This article is posted here by permission of University of Miami - Rosenstiel School of Marine and Atmospheric Science for personal use, not for redistribution. The definitive version was published in Bulletin of Marine Science 87 (2011): 275-299, doi:10.5343/bms.2010.1022.Barnacles are often abundant on roots and branches of mangrove trees in tidal channels and coastal lagoons of the Pacific coast of Panama. Yet, in some coastal lagoons, barnacles are absent. We investigated pre- and post-settlement factors that affect barnacle distributions in two adjacent coastal lagoons in BahĂa Honda, Panama, one with moderate to large barnacle populations, and the other with nearly non-existent populations. Although mean barnacle recruitment was higher on mangrove root segments during the dry season (December-April) than in the wet season (May-November), it was not significantly different between the two coastal lagoons. The coastal lagoon with fewer barnacles is considered an estuary, with high freshwater flow and low salinities (0.1) during the wet season that were lethal to barnacle nauplii and cyprids. Furthermore, coastal water was not observed to enter the lagoon, even during flood tides. In contrast, more barnacles were found in the lagoon with higher salinities (8.5). During the dry season, freshwater flow was greatly reduced in both lagoons, resulting in a similar salinity range (22-33). We conclude that the lack of barnacles in the estuarine coastal lagoon is largely due to high flushing rates and low salinities that reduce larval concentrations during the wet season. Moreover, low adult abundance in the lagoon's interior may further reduce larval supply and settlement.Finally, we would like to thank the Ocean Life Institute of the Woods Hole Oceanographic
Institution for funding to JP to complete research in the Liquid Jungle Lab.2014-07-0
Dominant circulation patterns of the deep Gulf of Mexico
Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 511-529, doi:10.1175/JPO-D-17-0140.1.The large-scale circulation of the bottom layer of the Gulf of Mexico is analyzed, with special attention to the historically least studied western basin. The analysis is based on 4 years of data collected by 158 subsurface floats parked at 1500 and 2500 m and is complemented with data collected by current meter moorings in the western basin during the same period. Three main circulation patterns stand out: a cyclonic boundary current, a cyclonic gyre in the abyssal plain, and the very high eddy kinetic energy observed in the eastern Gulf. The boundary current and the cyclonic gyre appear as distinct features, which interact in the western tip of the Yucatan shelf. The persistence and continuity of the boundary current is addressed. Although high variability is observed, the boundary flow serves as a pathway for water to travel around the western basin in approximately 2 years. An interesting discovery is the separation of the boundary current over the northwestern slope of the Yucatan shelf. The separation and retroflection of the along-slope current appears to be a persistent feature and is associated with anticyclonic eddies whose genesis mechanism remains to be understood. As the boundary flow separates, it feeds into the westward flow of the deep cyclonic gyre. The location of this gyre—named the Sigsbee Abyssal Gyre—coincides with closed geostrophic contours, so eddy–topography interaction via bottom form stresses may drive this mean flow. The contribution to the cyclonic vorticity of the gyre by modons traveling under Loop Current eddies is discussed.This work was supported by the
Bureau of Ocean Energy Management (BOEM) under
Contract M10PC00112 assigned to Leidos, Inc