Empirical orthogonal function analysis of cloud‐containing coastal zone color scanner images of northeastern North American coastal waters

Eslinger, David L.; O’Brien, James J.; Iverson, Richard L.

doi:10.1029/jc094ic08p10884

Cited by 30 publications

(10 citation statements)

References 20 publications

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“…EOF analysis is a useful tool for combining a large number of factors (in this case wavelengths) into a smaller number of uncorrelated components. This analysis has been widely used in meteorology (Lorenz 1956) and physical (Davis 19 7 6) and biological oceanography (Mueller 1976;Eslinger et al 1989).…”

Section: Resultsmentioning

confidence: 99%

Variability in near-surface particulate absorption spectra: What can a satellite ocean color imager see?

1994

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An extensive database of -400 in situ particulate absorption spectra [a,(X)] is analyzed to assess the potential of using ocean color imagers to examine variability in the structure of the near-surface ocean planktonic ecosystem. This application of a,(X) data is appropriate, as particulate absorption variations are the dominant source of ocean color variation and are attributable to changes in the phytoplankton community structure. Empirical orthogonal function (EOF') analyses are used to estimate the contribution of each statistical mode to the total variance. The EOF analyses showed that > 99% of the variance found in the a,(X) data set can be simply attributed to the total amount of particulate material. When this source of variability is removed, two significant modes of variability can be identified which comprise 79 and 18% of the normalized variance. These modes are interpreted as representing the relative contribution of chlorophyll-containing biomass and detrital materials, verifying the use of two-component phytoplankton-detritus models to partition a,(X). Only a small amount of the total a,(X) variability (~0.5% of the total) can be attributed to absorption features caused by accessory pigment groups. Thus, variability in a,(X) is almost entirely associated with the quantity of the absorbing materials rather than their spectral quality (or normalized spectral shape). These results suggest that remotely sensed ocean color spectra will reflect only three statistically significant components: the total amount of particulate material, the relative amounts of chlorophyll-containing biomass, and detrital materials. For most typical conditions it is unlikely that robust global algorithms for determining particular phytoplankton groups can be developed from remotely sensed ocean color spectra.

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Section: Resultsmentioning

confidence: 99%

Variability in near-surface particulate absorption spectra: What can a satellite ocean color imager see?

1994

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“…The authors point out the similarity of these patterns to those of vertical stability described many years earlier by Bigelow (1927) and quantified later by Garrett et al (1978) using the Simpson and Hunter (1974) model of tidal mixing and stratification. A statistical analysis of the spatial and temporal variance in 36 reduced resolution CZCS images over B4 months in 1979 by Eslinger et al (1989) over northeastern North American waters includes results for the Gulf of Maine. Examination of their figures suggests that, at least in 1979, the timing of pigment concentration increases over Georges Bank were out of phase with those in the western Gulf of Maine.…”

Section: Introductionmentioning

confidence: 99%

Satellite-measured phytoplankton variability in the Gulf of Maine

Thomas

Townsend

Weatherbee

2003

Continental Shelf Research

108

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The first 4 years of SeaWiFS ocean color data (September 1997-August 2001 provide the first synoptic quantification of seasonal and interannual phytoplankton chlorophyll variability in the Gulf of Maine. Climatological monthly means show spatial patterns associated with the annual cycle. Concentrations are elevated throughout the year in coastal regions and over shallow banks (Georges Bank, Nantucket Shoals and Browns Bank) with a spring and fall bloom superimposed. Over deeper basins and the Scotia Shelf, a canonical North Atlantic seasonal cycle is present with low (o 1 mg m À3 ) winter (December-February) concentrations, an annual maximum in March-April (>2 mg m À3 ), reduced concentrations in summer and a fall bloom beginning as early as September in Jordan Basin but in OctoberNovember over other regions. Strong interannual variability over the 4-year time series shows the climatological seasonal features are often a biased picture of both timing and magnitude. The clearest interannual signal is of reduced chlorophyll concentrations throughout 1998, including weak spring and fall blooms. A connection between low concentrations in 1998 and local wind forcing is not evident. However, the low concentrations are coincident with negative anomalies in satellite surface temperature fields and follow the intrusion of relatively cold, low salinity slope water into the Northeast Channel which previous authors have argued is linked to changes in Labrador slope water transport induced by the North Atlantic Oscillation. Reduced concentrations in 1998 are consistent with both lower nitrate/nitrite concentrations in the intruding water as well as reduced subsurface stratification which would delay or reduce the onset of the spring bloom. r

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“…The first instrument for remote sensing of ocean color, the CZCS, yielded almost 8 yr of imagery between fall 1978 and summer 1986 (Hovis 1980;Feldman et al 1989). CZCS imagery of this region has been used to study the spring bloom (Brown et al 1985;Eslinger and Iverson 1986;Walsh et al 1987a;Gregg and Walsh 1992), spatial and temporal modes of variation in pigment distributions (Eslinger et al 1989), WCR processes (Garcia-Moliner and Yoder 1994), absorption by chromophoric dissolved organic matter (Hoge et al 1995), and transport of acid wastes dumped in shelf water (Elrod 1988). Here, we use CZCS-derived pigment concentrations (CZCS-Chl) and other satellite and in situ data to examine fundamental attributes of annual chlorophyll enhancement at the shelfbreak.…”

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confidence: 99%

Enhanced chlorophyll at the shelfbreak of the Mid‐Atlantic Bight and Georges Bank during the spring transition

Ryan

Yoder

Cornillon

1999

Limnology & Oceanography

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In 8 yr (1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986) of Coastal Zone Color Scanner (CZCS) imagery, we find annual enhancement of chlorophyll at the shelfbreak of the Mid-Atlantic Bight (MAB) and Georges Bank during the spring transition from well-mixed to stratified conditions. Spatial and temporal extents of enhancement vary interannually, and expression is intermittent intraannually. This feature can span the entire MAB and southern flank of Georges Bank (ϳ1,100 km) and can be expressed for as long as 10 weeks (mid-April to late June). Pigment concentrations within the feature average more than two times that of adjacent shelf and slope waters. Enhanced shelfbreak chlorophyll consistently coincided with the shelf-slope front and often extended inshore of the surface outcrop of the front a few to ϳ10 km. In all years except 1986, it coincided with seaward entrainment of shelf water by Gulf Stream warm-core rings (WCRs) or meanders. Shelfbreak chlorophyll enhancement was most pronounced during 1980. Using satellite and in situ observations, we found that during 1980, it coincided with the shelf-slope front for 10 weeks, and, unlike the spring bloom, it was dominated by the nanophytoplankton (Ͻ20 m) size fraction. During the peak of the 1980 occurrence, four WCRs simultaneously interacted with shelf water, and chlorophyll enhancement inshore of one WCR coincided with a slope-water intrusion onto the shelf. Empirical orthogonal function (EOF) decomposition of CZCS images for late March-June 1980 showed that shelfbreak enhancement was strongly pronounced in an EOF that accounted for Ͼ10% of the variance about the mean. This annual biological feature, brought to light in satellite ocean color imagery, is an important aspect of the shelf-slope ecology of the MAB and Georges Bank.

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Empirical orthogonal function analysis of cloud‐containing coastal zone color scanner images of northeastern North American coastal waters

Cited by 30 publications

References 20 publications

Variability in near-surface particulate absorption spectra: What can a satellite ocean color imager see?

Variability in near-surface particulate absorption spectra: What can a satellite ocean color imager see?

Satellite-measured phytoplankton variability in the Gulf of Maine

Enhanced chlorophyll at the shelfbreak of the Mid‐Atlantic Bight and Georges Bank during the spring transition

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