"Algorithms for remote estimation of chlorophyll-a in coastal and inland waters using red and near infrared bands" (2010 Abstract: Remote sensing algorithms that use red and NIR bands for the estimation of chlorophyll-a concentration [Chl] can be more effective in inland and coastal waters than algorithms that use blue and green bands. We tested such two-band and three-band red-NIR algorithms using comprehensive synthetic data sets of reflectance spectra and inherent optical properties related to various water parameters and a very consistent in situ data set from several lakes in Nebraska, USA. The two-band algorithms tested with MERIS bands were R rs (708)/R rs (665) and R rs (753)/R rs (665). The three-band algorithm with MERIS bands was in the form R3 = [R rs 1 (665)  R rs 1 (708)] × R rs (753). It is shown that the relationships of both R rs (708)/R rs (665) and R3 with [Chl] do not depend much on the absorption by CDOM and non-algal particles, or the backscattering properties of water constituents, and can be defined in terms of water absorption coefficients at the respective bands as well as the phytoplankton specific absorption coefficient at 665 nm. The relationship of the latter with [Chl] was established for [Chl] > 1 mg/m 3 and then further used to develop algorithms which showed a very good match with field data and should not require regional tuning. 6, 28-36 (1985). (2010) 1161-1166 (1979). 12. A. Vasilkov, and O. Kopelevich, -Reasons for the appearance of the maximum near 700 nm in the radiance spectrum emitted by the ocean layer,‖ Oceanology (Mosc.) 22, 697-701 (1982). 13. Published in Optics Express

[1] We have developed a coupled ocean-atmosphere general circulation model, the GENESIS-MOM model, with the ability to transport and fractionate water isotopes in the ocean and atmosphere. The model is used to predict modern and Cretaceous precipitation and seawater d18 O. The model reproduces the large-scale modernday isotopic distribution. In the zonal mean, the difference between simulated and observed seawater d 18O is within 0.2% in the low and middle latitudes and within 1% at high latitudes. In comparison to modern, simulated Cretaceous surface seawater d18 O is systematically depleted by 0.3% at low and middle latitudes. These differences are attributed to equilibrium fractionation during surface evaporation at low latitudes and an increased partitioning of 18 O from the surface into the deep ocean due to intermediate and deep water formation in subtropical basins in the Cretaceous. We also find that regional seawater d 18O is significantly influenced by the paleobathymetry and the resolution of oceanic gateways, boundary conditions that are not well known for the past. Our simulation of Cretaceous seawater d18 O has major implications for oxygen isotope paleothermometry. We conclude that conventional assumptions of past seawater d 18O may lead to an overestimate of Cretaceous sea-surface temperatures, especially at middle and high latitudes.

Based on HYDROLIGHT simulations of more than 2000 reflectance spectra from datasets typical of coastal waters with highly variable optically active constituents as well as on intercomparisons with field measurements, the magnitude of chlorophyll fluorescence was analyzed and parameterized as a function of phytoplankton, CDOM, and suspended inorganic matter concentrations. Using the parameterizations developed, we show that variations in the fluorescence component of water leaving radiance in coastal waters are due more to the variability of attenuation in the water than to the variability of the fluorescence quantum yield, which we estimate to be relatively stable at around 1%. Finally, the ranges of water conditions where fluorescence plays a significant role in the reflectance NIR peak and where it is effectively undetectable are also determined.

Karenia brevis (K. brevis) blooms are of great interest and have been commonly reported throughout the Gulf of Mexico. In this study we propose a detection technique for blooms with low backscatter characteristics, which we name the Red Band Difference (RBD) technique, coupled with a selective K. brevis bloom classification technique, which we name the K. brevis Bloom Index (KBBI). These techniques take advantage of the relatively high solar induced chlorophyll fluorescence and low backscattering of K. brevis blooms. The techniques are applied to the detection and classification of K. brevis blooms from Moderate Resolution Imaging Spectroradiometer (MODIS) ocean color measurements off the Gulf of Mexico. To assess the efficacy of the techniques for detection and classification, simulations, including chlorophyll fluorescence (assuming 0.75% quantum yield) based on K. brevis blooms and non-K. brevis blooms conditions were performed. These show that effective bloom detection from satellite measurements requires a threshold of RBD>0.15W/m(2)/microm/sr, corresponding to about 5mg/m(3) of chlorophyll. Blooms can be detected at lower concentration by lowering the RBD threshold but false positives may increase. The classification technique is found most effective for thresholds of RBD>0.15W/m(2)/microm/sr and KBBI>0.3*RBD. The techniques were applied and shown to be effective for well documented blooms of K. brevis in the Gulf of Mexico and compared to other detection techniques, including FLH approaches. Impacts of different atmospheric corrections on results were also examined.

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