Satellite remote sensing of water turbidity in Alqueva reservoir and implications on lake modelling

Potes, Miguel; Costa, María João; Salgado, Rui

doi:10.5194/hess-16-1623-2012

Cited by 54 publications

(51 citation statements)

References 25 publications

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“…This is because the lower layers in dark waters accumulate less heat during the heating season as opposed to clear waters, which results in less heat storage and lower water column temperature in dark waters (Heiskanen et al, 2015;Potes et al, 2012). The MWCT decreased by 0.94 • C (increased by 0.63 • C) when maximum (minimum) K d value was used instead of its average value during the study period.…”

Section: Sensitivity Of Flake To K D Variationsmentioning

confidence: 97%

“…Their results showed that water clarity is an essential parameter affecting the simulated LSWT. The daily mean LSWT increased from 1.2 • C in clear water to 2.4 • C in dark water (Potes et al, 2012). Water clarity measurements are included in water quality monitoring programs; however, global measurements of clarity are not yet available.…”

Section: Introductionmentioning

confidence: 99%

“…In recent years, a number of algorithms have been devised to retrieve different water optical parameters, including water clarity, from satellite observations for coastal (ocean) and lake waters (Attila et al, 2013;Binding et al, 2007;Binding et al, 2015;Olmanson et al, 2013;Potes et al, 2012;Wu et al, 2009;Zhao et al, 2011;Zolfaghari and Duguay, 2016). Turbid inland and coastal waters are optically more complex compared to open ocean, and large optical gradients exist.…”

Section: Introductionmentioning

confidence: 99%

“…Potes et al (2012) used empirically derived water clarity from space-borne medium resolution imaging spectrometer (MERIS) measurements to test the sensitivity of FLake to this parameter. The sensitivity analysis was conducted using two K d values, representing the expected extreme water clarity cases for their study (1.0 m −1 for clear water and 6.1 m −1 for dark water).…”

Section: Introductionmentioning

confidence: 99%

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Satellite-derived light extinction coefficient and its impact on thermal structure simulations in a 1-D lake model

Zolfaghari

Duguay

Pour

2017

Hydrol. Earth Syst. Sci.

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Abstract.A global constant value of the extinction coefficient (K d ) is usually specified in lake models to parameterize water clarity. This study aimed to improve the performance of the 1-D freshwater lake (FLake) model using satellite-derived K d for Lake Erie. The CoastColour algorithm was applied to MERIS satellite imagery to estimate K d . The constant (0.2 m −1 ) and satellite-derived K d values as well as radiation fluxes and meteorological station observations were then used to run FLake for a meteorological station on Lake Erie. Results improved compared to using the constant K d value (0.2 m −1 ). No significant improvement was found in FLake-simulated lake surface water temperature (LSWT) when K d variations in time were considered using a monthly average. Therefore, results suggest that a timeindependent, lake-specific, and constant satellite-derived K d value can reproduce LSWT with sufficient accuracy for the Lake Erie station.A sensitivity analysis was also performed to assess the impact of various K d values on the simulation outputs. Results show that FLake is sensitive to variations in K d to estimate the thermal structure of Lake Erie. Dark waters result in warmer spring and colder fall temperatures compared to clear waters. Dark waters always produce colder mean water column temperature (MWCT) and lake bottom water temperature (LBWT), shallower mixed layer depth (MLD), longer ice cover duration, and thicker ice. The sensitivity of FLake to K d variations was more pronounced in the simulation of MWCT, LBWT, and MLD. The model was particularly sensitive to K d values below 0.5 m −1 . This is the first study to assess the value of integrating K d from the satellite-based CoastColour algorithm into the FLake model. Satellite-derived K d is found to be a useful input parameter for simulations with FLake and possibly other lake models, and it has potential for applicability to other lakes where K d is not commonly measured.

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Section: Sensitivity Of Flake To K D Variationsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Satellite-derived light extinction coefficient and its impact on thermal structure simulations in a 1-D lake model

Zolfaghari

Duguay

Pour

2017

Hydrol. Earth Syst. Sci.

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“…The reflectance in this spectral region increases towards the maximum at 565 nm. Potes et al (2012) showed a high correlation (0.96) between the water-leaving reflectance ratio 560Á412.5 nm and water turbidity for the Alqueva reservoir. The scatter plot for the ratio at or near the wavelengths of Potes et al (2012) was performed and presented a lower correlation with respect to the one presented here.…”

Section: Evaluation Of the Lake Modelmentioning

confidence: 99%

Evaluation of the lake model FLake over a coastal lagoon during the THAUMEX field campaign

Moigne¹,

Legain²,

Lagarde³

et al. 2013

Tellus A: Dynamic Meteorology and Oceanography

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A B S T R A C T The THAUMEX measurement campaign, carried out during the summer of 2011 in Thau, a coastal lagoon in southern France, focused on episodes of marine breezes. During the campaign, three intensive observation periods (IOPs) were conducted and a large amount of data were collected. Subsequently, standalone modelling using the FLake lake model was used, first to assess the surface temperature and the surface energy balance, and second to determine the energy budget of the water column at the measurement site. Surface fluxes were validated against in situ measurements, and it was determined that heat exchanges are dominated by evaporation. We also demonstrated that the model was sensitive to the light extinction coefficient at Thau, due to its shallowness and clarity nature. A heat balance was calculated, and the inclusion of a radiative temperature has improved it, especially by reducing the nocturnal evaporation. The FLake lake model was then evaluated in three-dimensional numerical simulations performed with the Meso-NH mesoscale model, in order to assess the changing structure of the boundary layer above the lagoon during the IOPs more accurately. We highlighted the first time ever when Meso-NH and FLake were coupled and proved the ability of the coupled system to forecast a complex phenomenon but also the importance of the use of the FLake model was pointed out. We demonstrated the impact of the lagoon and more precisely the Lido, a sandy strip of land between the lagoon and the Mediterranean Sea, on the vertical distribution of turbulent kinetic energy, evidence of the turbulence induced by the breeze. This study showed the complementarities between standalone and coupled simulations.

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Effects of water clarity on lake stratification and lake‐atmosphere heat exchange

et al. 2015

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Recent progress of including lake subroutines in numerical weather prediction (NWP) models has led to more accurate forecasts. In lake models, one essential parameter is water clarity, parameterized via the light extinction coefficient, K d , for which a global constant value is usually used. We used direct eddy covariance fluxes and basic meteorological measurements coupled with lake water temperature and clarity measurements from a boreal lake to estimate the performance of two lake models, LAKE and FLake. These models represent two 1-D modeling frameworks broadly used in NWP. The results show that the lake models are very sensitive to changes in K d when it is lower than 0.5 m À1. The progress of thermal stratification depended strongly on K d . In dark-water simulations the mixed layer was shallower, longwave and turbulent heat losses higher, and therefore the average water column temperatures lower than in clear-water simulations. Thus, changes in water clarity can also affect the onset of ice cover. The more complex LAKE modeled the seasonal thermocline deepening, whereas it remained virtually constant during summer in the FLake model. Both models overestimated the surface water temperatures by about 1°C and latent heat flux by >30%, but the variations in heat storage and sensible heat flux were adequately simulated. Our results suggest that, at least for humic lakes, a lake-specific, but not time-depending, constant value for K d can be used and that a global mapping of K d would be most beneficial in regions with relatively clear lakes, e.g., in lakes at high altitudes.

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Satellite remote sensing of water turbidity in Alqueva reservoir and implications on lake modelling

Cited by 54 publications

References 25 publications

Satellite-derived light extinction coefficient and its impact on thermal structure simulations in a 1-D lake model

Satellite-derived light extinction coefficient and its impact on thermal structure simulations in a 1-D lake model

Evaluation of the lake model FLake over a coastal lagoon during the THAUMEX field campaign

Effects of water clarity on lake stratification and lake‐atmosphere heat exchange

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