Corrigendum to Characterization of westward propagating signals in the South Atlantic from altimeter and radiometer records ”[Remote Sens. Environ., 134: 367-376]

Radar altimeter data from TOPEX/Poseidon and Jason-1 and microwave radiometer data from TRMM/TMI are used to investigate the large-scale variability between 10.5°S and 35.5°S in the South Atlantic Ocean. The proposed method for the analysis of the longitude–time diagrams of the cross-correlation between SSH and SST anomalies shows that the variability in mid latitudes is a blend of first-mode baroclinic Rossby waves and propagating mesoscale eddy-like structures. The estimated phase speed of the wave (cp) and propagation speed of the eddies (cv) are similar. In 70% of the cases, the absolute difference between cp and cv is less than 11%. In 40% of the cases this difference is less than 5%. Statistical results indicate that in the case of eddies, as the thermocline deepens the sea surface temperature rises and vice-versa. However, planetary waves show more complex, yet self-consistent results. In lower latitudes (10.5°S–15.5°S), the shallower thermocline and the weak thermal gradients impose a zero phase lag between temperature and height, similar to eddies. Poleward of those latitudes, sea surface temperature and height are in quadrature of phase. This indicates that geostrophic advection of the relatively stronger thermal gradient is performed by Rossby wave

Ocean kinetic energy and photosynthetic biomass are important drivers of planktonic foraminifera diversity in the Atlantic Ocean

To assess the anthropogenic effect on biodiversity, it is essential to understand the global diversity distribution of the major groups at the base of the food chain, ideally before global warming initiation (1850 Common Era CE). Since organisms in the plankton are highly interconnected and carbonate synthesizing species have a good preservation state in the Atlantic Ocean, the diversity distribution pattern of planktonic foraminifera from 1741 core-top surface sediment samples (expanded ForCenS database) provides a case study to comprehend centennial to decadal time-averaged diversity patterns at pre-1970 CE times, the tempo of the substantial increase in tropospheric warming. In this work, it is hypothesized and tested for the first time, that the large-scale diversity patterns of foraminifera communities are determined by sea surface temperature (SST, representing energy), Chl-a (a surrogate for photosynthetic biomass), and ocean kinetic energy (as EKE). Alpha diversity was estimated using species richness (S), Shannon Wiener index (H), and Simpson evenness (E), and mapped using geostatistical approaches. The three indices are significantly related to SST, Chl-a, and EKE (71-88% of the deviance in the generalized additive mixed model, including a spatial component). Beta diversity was studied through species turnover using gradient forest analysis (59% of the variation). The primary community thresholds of foraminifera species turnover were associated with 5-10 degrees C and 22-28 degrees C SST, 0.05-0.15 mg m-(3) Chl-a, and 1.2-2.0 cm(2) s-(2) log10 EKE energy, respectively. Six of the most important foraminifera species identified for the environmental thresholds of beta diversity are also fundamental in transfer functions, further reinforcing the approaches used. The geographic location of the transition between the four main biogeographic zones was redefined based on the results of beta diversity analysis and incorporating the new datasets, identifying the major marine latitudinal gradients, the most important upwelling areas (Benguela Current, Canary Current), the Equatorial divergence, and the subtropical fronts (Gulf Stream-North Atlantic Drift path in the north, and the South Atlantic current in the south). In conclusion, we provide statistical proof that energy (SST), food supply (Chl-a), and currents (EKE) are the main environmental drivers shaping planktonic foraminifera diversity in the Atlantic ocean and define the associated thresholds for species change on those variables.info:eu-repo/semantics/publishedVersio

Influence of Rossby waves on nutrient dynamics and the plankton community structure in the North Pacific subtropical gyre

Nitrate concentrations, chlorophyll a (Chl a) fluorescence, radiance, salinity, and temperature were measured on the Hawaii Air-Sea Logging Experiment, A Long-Term Oligotrophic Habitat Assessment (HALE ALOHA) mooring located near the Hawaii Ocean Time-Series (HOT) Program’s Station ALOHA (22°45’N; 158°W). Nitrate concentrations were determined with OsmoAnalyzers deployed at depths of 120 and 180 m. Deployments in 1997 and 1999 captured monthlong events that brought relatively cold high-nitrate seawater up into the euphotic zone. These events were correlated with negative sea surface height (SSH) anomalies measured by the TOPEX/Poseidon satellite altimeter. These nutrient injections at the Hawaii site were predominantly associated with first baroclinic mode Rossby waves. Elevated nitrate concentrations resulted in increased Chl a concentrations, increased primary productivity, and shifts in the phytoplankton community structure, as determined by HPLC analysis of pigment concentrations. The relative increase in pigments associated with phytoplankton that can grow rapidly and exploit nitrate (e.g., haptophytes and pelagophytes) coincided with the passage of Rossby waves in 1997–1999. A long-term combination of satellite remote sensing, moored instrumentation or remote vehicles and periodic ship-based sampling is needed to fully characterize the spatial and temporal variability due to the passage of Rossby waves and their associated biological responses.Keywords: nitrate, nutrient, Rossby waves, phytoplankton, mooringKeywords: nitrate, nutrient, Rossby waves, phytoplankton, moorin

Global interannual trends and amplitude modulations of the sea surface height anomaly from the TOPEX/Jason-1 altimeters

This study uses the global Ocean Topography Experiment (TOPEX)/Jason-1 altimeters` time series to estimate the 13-yr trend in sea surface height anomaly. These trends are estimated at each grid point by two methods: one fits a straight line to the time series and the other is based on the difference between the average height between the two halves of the time series. In both cases the trend shows large regional variability, mostly where the intense western boundary currents turn. The authors hypothesize that the regional variability of the sea surface height trends leads to changes in the local geostrophic transport. This in turn affects the instability-related processes that generate mesoscale eddies and enhances the Rossby wave signals. This hypothesis is verified by estimates of the trend of the amplitude of the filtered sea surface height anomaly that contains the spectral bands associated with Rossby waves and mesoscale eddies. The authors found predominantly positive tendency in the amplitude of Rossby waves and eddies, which suggests that, on average, these events are becoming more energetic. In some regions, the variation in amplitude over 13 yr is comparable to the standard deviation of the data and is statistically significant according to both methods employed in this study. It is plausible that in this case, the energy is transferred from the mean currents to the waves and eddies through barotropic and baroclinic instability processes that are more pronounced in the western boundary current extension regions. If these heat storage patterns and trends are confirmed on longer time series, then it will be justified to argue that the warming trend of the last century provides the energy that amplifies both Rossby waves and mesoscale eddies

Improved estimates of gas transfer using scatterometer

Current estimates of air-sea gas exchange vary by over a factor of two depending on the parameterization of the piston velocity from wind speed. Uncertainties in the parameterization occur because wind speed is not necessarily an accurate descriptor for the characteristics of the turbulent water boundary layer. Parameterizations derived from wind tank studies cannot account for all the processes occurring in the real ocean. Recent experimental tank and in situ results suggest that the dynamics of capillary waves are responsible for most gas transfer. In these tank experiments, gas transfer shows a higher correlation with the mean short wave slope than with wind speed. We want to calculate the gas exchange coefficient, E, from scatterometer measurements of surface roughness, which is related to the amplitude (or mean short wave slope)of gravity- capillary waves of approximately 4.5 to 6 cm. The exchange coefficient derived in this manner has higher spatial and temporal resolution than traditional estimates parameterized with wind-speed and over a similar altimieter-based approach. This increased resolution implies higher variability in E and likely more large values. From a global perspective the new parameterization of gas transfer will enable improved understanding of the magnitude and scales of variability in the uptake of fossil-fuel C02 by providing unprecedented coverage and resolution of E, a major source of uncertainty in the flux calculation.Pages: 753-75