Recurrent patterns in surface thermal fronts associated with cold filaments along the West Coast of North America

Randerson, James T.; Simpson, Joseph

doi:10.1016/0034-4257(93)90091-b

Cited by 9 publications

(3 citation statements)

References 51 publications

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“…Jaim, 1989) Several different filter kernels can be used with Eq. Randerson and Simpson ( 1992) computed distributions of gradient magnitude vs. gradient angle, using Eqs. Simpson ( 1990) quantitatively evaluated the performance of a wide variety of gradient filter kernels under varying noise conditions and found that either an isentropic or a Prewitt kernel should be used with satellite data.…”

Section: Errors Induced In Edge Detection By Improper Preprocessingmentioning

confidence: 99%

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Remote sensing and geographical information systems: Their past, present and future use in global marine fisheries

Simpson

1992

Fisheries Oceanography

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Historically, the fishing community (e.g., fishermen, resource managers) has used remotely sensed products either in the form of direct Automatic Picture Transmission (APT) reception on a ship or FAX charts transmitted from land‐based stations. Both these products have severe limitations within the context of near real‐time support/management of an operational fishery. Moreover, relatively little use of geographical information systems (GIS) technologies has been made by either the fishing industry, fishery resource managers, or by the general oceanographic community. This latter omission is unfortunate because GIS has the potential to overcome two long‐standing problems associated with satellite‐directed fisheries: 1) the absence of information due to clouds; and 2) the general lack of support for nonpelagic fisheries. This report gives the background, motivation, and essential design elements for use of a combined remote sensing/geographical information system (RS/GIS) in an operational fishery and illustrates how a combined RS/GIS approach can be used to mitigate some of the traditional limitations in satellite‐directed fisheries. Finally, an attempt is made to provide some possible directions this new technology may take during the 1990s.

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Section: Errors Induced In Edge Detection By Improper Preprocessingmentioning

confidence: 99%

“…A cutoff value of 0.1"C km-' is used because gradients below this value cannot be resolved by the AVHRR sensor, and hence must be treated as noise (Simpson, 1990). Randerson and Simpson ( 1992)…”

Section: Errors Induced In Edge Detection By Improper Preprocessingmentioning

confidence: 99%

Remote sensing and geographical information systems: Their past, present and future use in global marine fisheries

Simpson

1992

Fisheries Oceanography

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“…Ocean fronts are generally developed at the edge of the filaments (Haynes et al, 1993;Ramp et al, 1991), with a high gradients in water properties. However, fronts may not be formed at the edges of all filaments (Randerson & Simpson, 1993) due to the diffusive boundaries rather than sharp gradients at the edge of some filaments. (Taylor & Ferrari, 2011).…”

Section: Introductionmentioning

confidence: 99%

Particulate Organic Carbon Composition in Temperature Fronts of the Northeastern Arabian Sea during Winter

et al. 2018

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In order to understand the major sources of particulate organic carbon (POC) in the frontal zones and to examine their variability with space and time, a total of five temperature fronts of different ages was sampled in the northeastern Arabian Sea during winter. Compared to the nonfrontal regions, POC and chlorophyll‐a were higher within the coastal fronts, whereas chlorophyll‐a was lower within the open ocean front (T1). The variation of POC between coastal and open ocean fronts is attributed to the combined influence of variable vertical mixing, heterotrophic transformation and age of the front. Relatively depleted δ13CPOC and δ15NPN were observed within the fronts, suggesting that POC pool is contributed by in situ production supported by upwelling of nutrient‐rich water and zooplankton biomass. Elemental C:N ratios, POC:Chl‐a, δ13CPOC, and δ15NPN suggest that POC is mainly contributed from primary producers and heterotrophs in the study region. However, relative contributions from these two sources vary spatially from coastal to open ocean and with the age of the front. Stable Isotope Analysis in R (SIAR) model revealed that zooplankton biomass largely contributed to POC in the open ocean (60–80%) than phytoplankton (20–40%) and nearly equal contribution was observed in the coastal fronts (50–60% and 40–50%, respectively). This study, thus, demonstrates that dominant heterotrophy and autotrophy in the open ocean and coastal fronts and it is consistent with their biomasses. Predominant heterotrophy in the open ocean is attributed to deeper mixed layer resulting in upwelling of bacteria‐rich and phytoplankton‐poor water to surface leading to existence of microbial loop.

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Autonomous tracking of an oceanic thermal front by a Wave Glider

Zhang

Rueda

Kieft

et al. 2019

Journal of Field Robotics

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Temporal variation in the structure and location of dynamic ocean features make them challenging to observe. Beyond requiring sufficient persistence and speed of the sensor platform, effective observation is augmented by autonomous feature detection coupled with adaptive localization of mapping effort. These capabilities enable observations to remain localized within and around features of interest, thereby enhancing spatial and temporal resolution in their depiction. A Wave Glider is a wave‐propelled unmanned surface vehicle with solar energy collection to support payload and a backup propeller in calm sea state. The efficiency of this platform enables persistence (months), and its propulsion system provides speed (~1 m/s). Building on these capabilities, we aim at enabling the Wave Glider to autonomously recognize and track oceanic features that have strong surface expressions, accessible to near‐surface sensors. We present a method of using a Wave Glider to autonomously track an oceanic thermal front known to have biological importance and dynamic evolution. In October 2017, this method was applied to tracking and mapping an upwelling front in Monterey Bay, CA, over 39 hr. The field result demonstrates adaptive localization of mapping based on autonomous feature detection.

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Recurrent patterns in surface thermal fronts associated with cold filaments along the West Coast of North America

Cited by 9 publications

References 51 publications

Remote sensing and geographical information systems: Their past, present and future use in global marine fisheries

Remote sensing and geographical information systems: Their past, present and future use in global marine fisheries

Particulate Organic Carbon Composition in Temperature Fronts of the Northeastern Arabian Sea during Winter

Autonomous tracking of an oceanic thermal front by a Wave Glider

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