Airborne remote sensing of chlorophyll distributions in Mono Lake, California

Mélack, John M.; Gastil, Mary

doi:10.1007/978-94-017-2934-5_3

Cited by 11 publications

(13 citation statements)

References 26 publications

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“…Remote sensing, whether from aircraft (Melack & Gastil, 2001;Lopez-Blanco & Zambrano, 2002) or satellite sensors (Lillesand et al, 1983) provides a powerful tool for the study of lake and pond ecology characteristics, such as water clarity and chlorophyll-a concentrations, for thousands of lakes. Because SDT can be estimated from light reflected from open lake water, SDT can be used to estimate pelagic algal biomass and to estimate lake trophic state due to suspended phytoplankton.…”

Section: Introductionmentioning

confidence: 99%

Alternate Stable States and the Shape of the Lake Trophic Distribution

et al. 2006

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Ecological theory applied to small and shallow lakes suggests that water clarity and primary productivity may be bimodal, reflecting alternate stable states. This hypothesis was tested using remote sensing data. We used estimated Secchi disk transparency derived from reflected light measured by Landsat satellite photosensors. Lake trophic state indices (TSI) were estimated from the transparency estimates. Because alternate stable state theory is typically applied to productive lakes, we predicted that planktonic primary productivity would be especially bimodal in the small and shallow eutrophic lakes of southern Wisconsin. We found that overall, trophic state for over 8000 lakes in Wisconsin was multimodal (at least bimodal). Frequency distributions for lake size categories appeared to be distinctly bimodal. The largest and smallest lakes for all of Wisconsin had significantly bimodal curves, and southern (more productive) lakes had a more distinct multimodal curve than northern lakes. These results support the basic predictions of alternate stable state theory. The significantly trimodal distribution for southern lakes suggests that they may exist in more than just two alternate stable states.

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Section: Introductionmentioning

confidence: 99%

Alternate Stable States and the Shape of the Lake Trophic Distribution

et al. 2006

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“…Recent field studies provide evidence that a one-dimensional approach of mixing in the metalimnion is not sufficient to explain the vertical flux of particles in stratified water bodies (Wüest et al, 1996;Ostrovsky et al, 1996;MacIntyre et al, 1999). Instead, a two-dimensional approach is needed to describe the movements of particles where the vertical transport occurs at the boundaries, supported by the turbulence in the BBL, and then advective processes, intrusions from mixing (Thorpe, 1998;McPhee-Shaw and Kunze, 2002) or gyres (Melack & Gastil, 2001) provide lateral transport of water and its constituents from the BBL towards the lake interior.…”

mentioning

confidence: 98%

Exchange between littoral and pelagic waters in a stratified lake due to wind-induced motions: Lake Kinneret, Israel

Marti

Imberger

2007

Hydrobiologia

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We used field data and three-dimensional numerical simulations to investigate the exchange processes between the lake boundaries (littoral) and lake interior (pelagic) due to wind-induced motions in Lake Kinneret, Israel. The field data showed largescale metalimnion oscillations with amplitudes up to 10 m in response to westerly diurnal winds, the existence of a well-defined turbidity intrusion into the metalimnion of the lake and a benthic boundary layer (BBL). The observed vertical and horizontal movements of the turbidity were explained by the vertical and horizontal advection associated with basin-scale wave motions and a residual circulation set up by the basin-scale motions and the wind field. The horizontal advective transport in the metalimnion, associated with the velocities induced by the basin-scale modetwo Poincaré wave, provided the primary control for the exchange between the lake boundaries and lake interior on daily time scales. Detailed comparison of simulation results with both temperature and velocity profiles revealed excellent agreement for time scales from hours to days. The validated numerical model was used to extract the residual motions that provided the secondary exchange flows, in the various regions of the lake on time scales from days to weeks. The residual motion in the surface layer consisted of a combination of an anticlockwise gyre in the western half of the lake and a weak clockwise gyre along the eastern boundary that were forced by the curl of the wind field. In the metalimnion, residual motions were predominantly forced by the basin-scale internal wave motions and an anticlockwise gyre established itself throughout the whole basin. Lastly in the BBL, residual motions consisted of an anticlockwise gyre, but the geographic distribution was patchy. Together these results provide new insight into a proper characterization of the processes underlying the flux paths of water and particles between the lake boundaries and lake interior.

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“…Dierssen et al, (2003) used spectral ratios derived from Ocean PHILLS imagery of shallow Bahamian waters to extract bathymetry and bottom type; used spectrum matching for the same purpose on the same imagery. Sandage and Holyer (1998) used a neural network to determine bathymetry from AVIRIS imagery of Florida waters, and Melack and Gastil (2001) used AVIRIS to map phytoplankton concentrations in Mono Lake, California. In all cases, the exploitation of hyperspectral imagery for shallow waters depends on being able to extract information about water-column optical properties, bathymetry, or bottom type from remote-sensing reflectance spectra.…”

Section: Introductionmentioning

confidence: 99%

A Spectrum-Matching and Look-Up-Table Approach to Interpretation of Hyperspectral Remote-Sensing Data

Mobley¹

2004

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Public reporting burden for this collection of information is estimated to average 1 fiour per response, including tfie time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of Infomiatlon. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Washington Headquarters Services, Directorate for Infomiation Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and A spectram-matching and look-up-table (LUT) methodology has been developed and evaluated for extracting environmental information from remotely sensed hyperspectral imagery. The LUT methodology works as follows. First, a database of remote-sensing reflectance (/?rs) spectra corresponding to various water depths, bottom reflectance spectra, and water-column inherent optical properties (lOPs) is constructed using a special version of the Hydrolight radiative transfer numerical model. Second, the /?" spectrum for a particular image pixel is compared with each spectrum in the database and the closest match to the image spectrum is found using a least-squares minimization. The environmental conditions in nature are then assumed to be the same as the input conditions that generated the closest-matching Hydrolight-generated spectrum in the database. The LUT methodology has been evaluated by application to an Ocean PHBLLS (Portable Hyperspectral Imaging Low-Light Spectrometer) image acquired near Lee Stocking Island, Bahamas, on 17 May 2000. The LUT-retrieved bottom depths were on average within 5% and 0.5 m of independently obtained acoustic depths. The LUT-retrieved bottom classification was in qualitative agreement with diver and video spot classification of bottom types, and the LUT-retrieved lOPs were consistent with lOPs measured at nearby times and locations. SUBJECT TERMSlook-up- First, a database of remote-sensing reflectance (RJ spectra corresponding to various water depths, bottom reflectance spectra, water-column inherent optical properties (lOPs), sky conditions, and viewing geometries is assembled. This database is constructed using the a special version of the Hydrolight radiative transfer numerical model, which provides an exact solution of the unpolarized radiative transfer equation for the given input. Each Hydrolight-generated /?" spectrum in the database is tagged by indices that identify the bottom depth, bottom reflectance spectrum, water lOPs, sun zenith angle, etc. that were used as input to the Hydrolight run. At a minimum, this database should contain R^ spectra generated for environmental conditions close to those occurring in nature at the time and location where the image was acquired. The database also may contain spectra corresponding to environmental conditions much different from those of the image under consideration.Second, the /?" spectrum for a particular image pixel is compared with each spect...

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Airborne remote sensing of chlorophyll distributions in Mono Lake, California

Cited by 11 publications

References 26 publications

Alternate Stable States and the Shape of the Lake Trophic Distribution

Alternate Stable States and the Shape of the Lake Trophic Distribution

Exchange between littoral and pelagic waters in a stratified lake due to wind-induced motions: Lake Kinneret, Israel

A Spectrum-Matching and Look-Up-Table Approach to Interpretation of Hyperspectral Remote-Sensing Data

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