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This paper proposes a new approach to apply neural network and multiple linear regression (MLR) methods to predict the state of El Niño–Southern Oscillation (ENSO). The simulated parameters (Nino3, Nino3.4, and Nino4 indices) are divided into two components: low-frequency and high-frequency. Multilayer neural networks (MNNs) are used to simulate the high-frequency component, and MLR is used to study the low-frequency component. One feature of the approach is the detailed selection of predictors as input data to the model and subsequent simulating with search and verification of all possible constructions of the multilayer neural network. Based on the new approach, a model for forecasting extreme phases of ENSO phenomenon—Neural Network Model for ENSO forecast (NNM-ENSOv1)—is developed. The resulting model is characterized by low sensitivity to the spring predictability barrier. That is why the this model properties are significantly better compared to dynamic models. The forecast lead time of ENSO event state of this model is longer by 7 months. The model was verified over the control period from 2007 to 2022. NNM-ENSOv1 reproduces not only El Niño (EN) events, but also their type with a lead time of up to 1 year quite well. As a confirmation, we note that four out of five EN events, including their type, are predicted correctly. The probability of correctly identifying conditions typical of EN events is quite high and changes slightly within 76–83% when the forecast lead time changes within 11 months, while for La Niña (LN) the probability of correct identification decreases from 85 to 31% with an increase in lead time. Using the NNM-ENSOv1 model in November 2022, a forecast of the ENSO state in 2023 is constructed. This model successfully predicted the evolution of LN that occurred until February 2023, next, the subsequent neutral conditions in March–April and the onset of East Pacific EN from May 2023. As a result, the forecast for the first half of 2023 is confirmed. ENSO modeling results in real time are available on the model's website at neuroclimate.com. [ABSTRACT FROM AUTHOR]

This paper analyzes the ability of three conceptual stochastic models (one-box, two-box, and diffusion models) to reproduce essential features of sea surface temperature variability on intra-annual time scales. The variability of sea surface temperature, which is particularly influenced by feedback mechanisms in ocean surface–atmosphere coupling processes, is characterized by power spectral density, commonly used to analyze the response of dynamical systems to random forcing. The models are aimed at studying local effects of ocean–atmosphere interactions. Comparing observed and theoretical power spectra shows that in dynamically inactive ocean regions (e.g., north-eastern part of the Pacific Ocean), sea surface temperature variability can be described by linear stochastic models such as one-box and two-box models. In regions of the world ocean (e.g., north-western Pacific Ocean, subtropics of the North Atlantic, the Southern Ocean), in which the observed sea surface temperature spectra on the intra-annual time scales do not obey the ν − 2 law (where ν is a regular frequency), the formation mechanisms of sea surface anomalies are mainly determined by ocean circulation rather than by local ocean–atmosphere interactions. The diffusion model can be used for simulating sea surface temperature anomalies in such areas of the global ocean. The models examined are not able to reproduce the variability of sea surface temperature over the entire frequency range for two primary reasons; first, because the object of study, the ocean surface mixed layer, changes during the year, and second, due to the difference in the physics of processes involved at different time scales. [ABSTRACT FROM AUTHOR]

This paper analyzes the ability of three conceptual stochastic models (one-box, two-box, and diffusion models) to reproduce essential features of sea surface temperature variability on intra-annual time scales. The variability of sea surface temperature, which is particularly influenced by feedback mechanisms in ocean surface–atmosphere coupling processes, is characterized by power spectral density, commonly used to analyze the response of dynamical systems to random forcing. The models are aimed at studying local effects of ocean–atmosphere interactions. Comparing observed and theoretical power spectra shows that in dynamically inactive ocean regions (e.g., north-eastern part of the Pacific Ocean), sea surface temperature variability can be described by linear stochastic models such as one-box and two-box models. In regions of the world ocean (e.g., north-western Pacific Ocean, subtropics of the North Atlantic, the Southern Ocean), in which the observed sea surface temperature spectra on the intra-annual time scales do not obey the ν−2 law (where ν is a regular frequency), the formation mechanisms of sea surface anomalies are mainly determined by ocean circulation rather than by local ocean–atmosphere interactions. The diffusion model can be used for simulating sea surface temperature anomalies in such areas of the global ocean. The models examined are not able to reproduce the variability of sea surface temperature over the entire frequency range for two primary reasons; first, because the object of study, the ocean surface mixed layer, changes during the year, and second, due to the difference in the physics of processes involved at different time scales.

An improved method is proposed for forecasting monthly precipitation in the mountain Crimea based on a model of artificial neural network. The input parameters of the model where taken in the form of a set of climatic indices of the global ocean–atmosphere system over 1948–2020, calculated based on reanalysis data NCEP/NCAR and HadISST1. The model was verified for the control period of 2007–2020. The possibility of seasonal forecast of precipitation with a lead time of up to 6 months was demonstrated. The model was shown to adequately forecast the total precipitation in winter, summer, and autumn (September and October) months. The forecast of precipitation in winter in the mountain Crimea is of particular importance in what regards the filling of local reservoirs, as ~70% of its total sum falls in this period of the year. It is shown that precipitation for winter can be forecasted in October and, with a higher forecast accuracy, in December. The forecast quality was 62 and 56%, respectively. In April, summer precipitation and precipitation in September–October can be forecasted (at a forecast quality of 55%). Parallel to precipitation, the possibility to make seasonal forecasts of atmospheric precipitation was checked and confirmed. [ABSTRACT FROM AUTHOR]

A possibility of the early prediction of El Niño and La Niña phenomena taking into account their two types (Central Pacific and East Pacific ones) is studied. The prognostic model is based on the method of artificial neural networks. A set of global climate indices for the period of 1950–2019 is used as the input parameters of the model. The indices are calculated using monthly mean NCEP/NCAR reanalysis data on 500 hPa geopotential height and sea-level pressure. The model is verified for the period of 2010–2019. A possibility of the successful forecast of Niño 3.4, Niño 4, and Niño 3 indices with a lead time of 3 to 9 months is shown. The quality of the forecast decreases as its lead time increases, but remains generally high. It is found that the model can predict well the El Niño beginning and evolution and, a bit worse, La Niña events; in this case, the number of La Niña events is overestimated as the forecast lead time increases. [ABSTRACT FROM AUTHOR]

The potential of using data of long-term AMSR-E (EOS Aqua satellite) microwave radiometer measurements for the determination of heat fluxes in the North Atlantic energy active zones in 2003–2011 is investigated. It is shown that there is a direct (linear regression) correlation between seasonal and interannual variations in average monthly vertical turbulent fluxes of total (sensible and latent) heat at the sea surface and brightness temperature of the ocean-atmosphere system in these zones. It is found that the highest accuracy of reproducing variations in average monthly brightness temperature can be reached using AMSR-E radiometer channels which are sensitive to the total column water vapor and sea surface temperature. [ABSTRACT FROM AUTHOR]

A review of contemporary methods for determining integrated parameters of the water content in the atmosphere-atmospheric water-vapor content and cloud liquid-water content-is presented. Fields of these parameters can only be mapped spatially on the basis of using data of satellite measurements. The least errors of the retrieval of atmospheric water-vapor content and cloud liquid-water content is provided by methods based on using measurements of the satellite-borne scanning multichannel microwave radiometers over the ice-free ocean areas in the absence of precipitation. Most methods for retrieving the atmospheric water-vapor content and cloud liquid-water content from the data of microwave radiometers are based on results of numerical simulation of brightness temperatures of the upwelling microwave radiation of the ocean-atmosphere system. The evolution of satellite-borne microwave radiometers and methods for the retrieval of integrated parameters of water content is presented. [ABSTRACT FROM AUTHOR]

RAINFALL VARIABILITY IN PORTUGAL AND SOME RELATIONS WITH THE OCEAN-ATMOSPHERE SYSTEM IN THE NORTH ATLANTIC - The scope of this study is to analyse rainfall variability in the Portuguese rainy season (Nov-Mar) during the 20th century, and examine some relations with the sea surface temperatures (SST) and geopotencial heights at 850 hPa (Z850) in the North Atlantic region. To build the Portuguese rainfall index (PRI), a principal component analysis (PCA) was performed on a matrix containing seven Portuguese stations with secular records (variables) and the years 1900 to 1993 (observations). This index is the first principal component (PC), which explains always over 60% of the total variance and all the seven stations used in the PCA have positive correlationswith the first component. Therefore we can assume that the first PC describes the rainfall variability in Portugal and the PCA has detectedonly one coherent area in Portuguese territory. The analysis of cycles reveals a variability that might be linked with the North Atlantic ocean atmosphere system. Very significant cycles of 3/4 or 7/8 years were found either in the PRI or in the first PC of SST time-series. In order to search the causes of the rainfall variability in Portugal, several correlations and composites analysis were made. Correlations between the PRI and the North Atlantic Oscillation (NAO) index are always negative for all rainy season months (Nov-Mar). The correlation between the PRI and the SST in North Atlantic shows a central area with significant negative coefficients (west of Portuguese coastline). Positive correlations above 50ºN and below 30ºN. The correlation between the PRI and Z850 field shows a North Atlantic Oscillation (NAO) pattern: positive correlations in the north and negative correlations in the south of North Atlantic region. In additon, a compositive analysis was made for wet and dry years to test the reaction of the SST field. A distinct pattern was found in the SST field for wet and dry years

Tropical ocean–atmosphere system exerts powerful control on the precipitation variations around the Pacific Ocean area where interactions among monsoon system, Intertropical Convergence Zone (ITCZ) migration, and other tropical ocean circulations modulate the regional climate changes in centennial-scale. However, little high-resolution information is known about the paleoenvironment changes in this area during the Holocene. In this study, a composite sediment profile, approximately 16 m in length, recovered from Shuangchiling (SCL) maar lake in Hainan Island, northern margin of western tropical Pacific, was selected to investigate the lake-level fluctuations, net precipitation variations, and the influence of the ocean–atmosphere system. Stable isotope (δ13C, δ15N) analyses, total organic carbon (TOC), and total nitrogen (TN) concentration measurements, as well as grain-size estimations revealed a two-stage evolution scenario for the lake dating back to 9 cal. kyr BP. The first stage spans a period of time from ~9 to ~3 cal. kyr BP, once the lake was characterized by shallow or ephemeral conditions. The second stage occurred from 3 to 0.6 cal. kyr BP and was characterized by a deeper water environment with substantial lake-level changes. All climate proxies suggest that the ocean–atmosphere variabilities, such as El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) activities, had a dominant influence on the regional net precipitation (the difference between precipitation and evaporation) and lake-level fluctuations. A three-step change of clay percentage at ~3, ~2.2, and ~1.3 cal. kyr BP correlate well with the ENSO proxy records from the eastern tropical Pacific. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study is to investigate the vulnerability of the Brazilian and western African Large Marine Ecosystems (LMEs) to local and remote forcing, including the Pacific Decadal Oscillation (PDO) regime shift. The analyses are based on the total and partial correlation between climate indices (Niño3, tropical South Atlantic (TSA), tropical North Atlantic (TNA) and Antarctic oscillation (AAO) and oceanic and atmospheric variables (sea surface temperature (SST), wind stress, Ekman transport, sea level pressure and outgoing longwave radiation). Differences in the correlation fields between the cold and warm PDO indicate that this mode exerts a significant impact on the thermodynamic balance of the ocean–atmosphere system on the South Atlantic ocean, mainly in the South Brazil and Benguela LMEs. The PDO regime shift also resulted in an increase in the spatial variability of SST and wind stress anomalies, mainly along the western African LMEs. Another important finding is the strong AAO influence on the SST anomalies (SSTA) in the South Brazil LME. It is also striking that TSA modulates the relation between El Niño–Southern Oscillation (ENSO) and SSTA, by reducing the influence of ENSO on SSTA during the warm PDO period in the North and East Brazil LMEs and in the Guinea Current LME. The relation between AAO and SSTA on the tropical area is also influenced by the TSA. The results shown here give a clear indication that future ecosystem-based management actions aimed at the conservation of marine resources under climate change need to consider the high complexity of basin-scale interactions between local and remote climate forcings, including their effects on the ocean-atmosphere system of the South Atlantic ocean. [Copyright &y& Elsevier]

An extended reanalysis, a combination of observations and model output, is used to examine the spatial patterns of physical variables associated with the Atlantic Multidecadal Oscillation (AMO) from 1871 to 2008. The results are presented as anomalies during positive and negative phases of the AMO. As in previous studies, during positive (negative) AMO phases the sea surface temperature (SST) is anomalously warm (cold) over most of the North Atlantic, with the exception of the east coast of the United States. The atmospheric patterns, associated with the positive phase of the AMO, include anomalous low pressure over the Atlantic between 20°S and 50°N, cyclonic surface winds around the low, reduced wind speeds over the tropical Atlantic and enhanced precipitation in the eastern tropical Atlantic, with roughly opposite conditions during negative AMO phases. There are, however, substantial differences in the SST and the atmospheric anomalies between periods of the same phase, especially in the extratropics. Correlations between the AMO and air temperature anomalies are positive over much of the globe between 40°S and 50°N, with correlations exceeding 0.6 (~95% significance level) over the Maritime Continent and northern rim of the Pacific Ocean. Most of the sea level pressure (SLP) anomalies beyond the Atlantic are not statistically significant. [ABSTRACT FROM AUTHOR]

We consider some peculiarities of the behavior of thermal and radio thermal (microwave radiation) characteristics of the atmosphere during prestorm situations in water areas monitored directly and remotely. The objects of research are (a) a region of the SMKF1 station (Sombrero Key) in the Florida Straight in August 2005 and (b) Golubaya Bay in the Black Sea (Gelendzhik, the territory of the Southern Branch of the Shirshov Institute of Oceanology, Russian Academy of Sciences) in September 2010, several days before an intensive storm. Using meteorological and satellite microwave radiometric data, we have studied some common and specific features in the behavior of surface air temperature and humidity, surface fluxes of sensible and latent heat, total heat and water vapor content of the atmosphere, and microwave radiation characteristics of the 'water surface-atmosphere' system during time periods preceding the approach of Hurricane Katrina to the region of SMKF1 and development of the sea storm near the Golubaya Bay. In both cases the effect of the accumulation of the latent heat of water vapor in the atmosphere was observed during the prestorm periods (of several days). [ABSTRACT FROM AUTHOR]

Abstract: The performance of the Weather Research and Forecast (WRF) mesoscale model in the ocean surface wind simulation was assessed and evaluated under different initial and boundary forcing conditions. Due to the continuous evolution and progress in the development of reanalyses datasets, this work aims to compare different WRF forcings through reanalyses datasets that are currently kept up to date in near real-time. These datasets consists of the first generation reanalysis NCEP-R2 and two recently released reanalysis datasets that represent the new generation of this type of data (ERA-Interim and NCEP-CFSR). These three reanalyses datasets were used as initial and boundary conditions for the WRF model to simulate surface oceanic wind simulations offshore of the Iberian Peninsula region (more specifically, on the Galician coast and the Gulf of Cádiz). The results are compared with observed wind data from five buoys that measure the wind in the selected region, with the objective of determining which of the three reanalyses produces more accurate wind simulations. The results show that simulations driven with ERA-Interim reanalysis present lower errors when compared to measured winds. This approach provides the most realistic initial and boundary data that can generate ocean wind simulations closest to real winds, although the NCEP-CFSR simulation results are very similar to those obtained with ERA-Interim. The NCEP-R2 reanalysis showed higher errors when compared to the new generation reanalyses. Based on the analysis and results presented in this work, it can be concluded that, for the area under study, the new generation reanalyses are considerably better for ocean wind simulations than the older reanalyses. This is in agreement with the improvement of the models, measurements and data assimilation that are used in the building of the reanalysis datasets. The higher spatial resolutions, the larger amount of assimilated measured data and the improvements of the data assimilation and correction techniques of ERA-Interim and NCEP-CFSR reanalyses data allow for a more accurate and realistic representation of the local wind climate. [Copyright &y& Elsevier]

Abstract: Under the International Polar Year endorsed project (IPY#70), the southwest Indian Ocean sector of the Southern Ocean was surveyed during the austral summer of 2008 by deploying expendable CTD probes along the ship tracks : Cape Town–India Bay, Antarctica (Track-1) and Prydz Bay, Antarctica–Cape Town (Track-2). The meteorological data revealed that the unstable marine atmosphere boundary layer (MABL) facilitated a turbulent heat loss of 45Wm− 2 on average, in conditions of variable wind intensity north of 43°S along Track-1; south of 63°S and north of 51°S the ocean was conducive to higher turbulent heat loss amounting to 95Wm−2 (on average) along Track-2. Surface imprints of hydrological fronts were determined by using surface gradient and subsurface temperature and salinity indicators. The core of Agulhas Current was identified between 36.5° and 37.5°S along Track-2, while the Agulhas Retroflection (AR) Front was located at 39.7°S south of Cape Town. The Subtropical (STF), Subantarctic (SAF) and Polar Fronts (PF) exhibited double frontal structures, whose meridional meandering is governed by bottom topography and modulated by planetary vorticity. A large southward deviation in the position of southern PF by 3.5° latitude on Track-1 was observed. Northern and southern SAF and southern STF meander by 2°–3.5° northward; their merger just north of Crozet Island facilitate an enhanced baroclinic transport of 12Sv in the upper 1000m. Three anticyclones that detach from the AR transport 17Sv into the southeast Atlantic. The baroclinic transport contributed by AC and its retroflection across Track-2 amounted to 17.6Sv. More than 50% of the ACC transport was confined to the 100–500m depth layer. Water masses have been identified and their zonal extent quantified along the tracks. Strong convective cooling is responsible for the production of Subtropical Mode Water in the eastern Crozet Basin, which was detected near 43.5° and 41.5°S along Track-1 and -2, respectively. The Circumpolar Deep Water was encountered between 600 and 900m at 51°S on Track-1 and spanned 54°–60°S on Track-2. We also offer an example of the modification of the MABL through strong air–sea interaction in the vicinity of South Africa by employing satellite-derived surface winds and heat fluxes. [Copyright &y& Elsevier]

Abstract: ERA-40 and NCEP-DOE global Reanalysis and the global tropospheric FNL analysis are compared with observations from the EPIC2001 experiment and data from TAO moorings along W, to assess how they represent the atmospheric conditions in the East Pacific. All analyses represent reasonably well the mean vertical wind profiles in the atmospheric boundary layer (ABL) and at all heights within the Intertropical Convergence Zone (ITCZ) at W. However, mean vertical zonal wind profiles show a poor agreement in the layer 850–600hPa from the equator to N. This could cause differences in reproducing the surface meridional pressure gradient, as a result of geostrophic dynamics (Raymond, Bretherton, Molinari, 2006. Dynamics of the Intertropical Convergence Zone of the East Pacific. J. Atmos. Sci. 63, 582–597), that drives the meridional flow into the ITCZ. vertical profiles, surface fluxes and near-surface temperature present appreciable differences with observations between the equator and N, suggesting that these global analyses must be used with caution in that region. Analyses seem to represent fairly well the time evolution of the surface meridional wind in the ITCZ and also the transitions of the zonal winds at 850hPa, as a result of the easterly wave passages over the region. Westerly periods in the ITCZ are associated with strong surface southerly winds, which result in enhanced convection and indicate an increase in the relative circulation of the region. In addition, easterlies coincide with a decrease in relative circulation, which could be related to the decrease in the convective activity. The averaged wind field in the ITCZ is reasonably well reproduced by all datasets, supporting their use in dynamical studies in the region. Unfortunately, the same cannot be said for the relative circulation and detrained mass flux since they show large differences with observations. In general, all analyses could be used to study mean conditions over the study region, taking into account the described limitations. [Copyright &y& Elsevier]

Abstract: Water mass variations in the northeastern Atlantic Ocean along 20°W are analyzed with pentadal resolution over the past 15 years using data from four repeat occupations of a meridional hydrographic section running south from Iceland. The section was sampled in 1988, 1993, 1998, and 2003. The results are interpreted in the context of changes in air–sea forcing, ocean circulation, and water properties associated with the North Atlantic Oscillation (NAO). The NAO index oscillated around zero from 1984 to 1988, was strongly positive from 1989 to 1995, after which it shifted to lower positive, and occasionally negative values from 1996 to 2003. Previously published studies suggest that after the 1995–1996 shift of the NAO, the subpolar gyre largely retreated to the northwest in the northeastern Atlantic Ocean, resulting in an increasingly southeastern character of local water masses with time. Water property changes extending from the SubPolar Mode Water (SPMW) just below the seasonal pycnocline through the density range shared by Mediterranean Outflow Water and SubArctic Intermediate Water (SAIW) along 20°W are consistent with changes in wind-driven ocean circulation and air–sea heat flux associated with shifts in the NAO, especially after accounting for ocean memory. After periods of lower NAO index the SPMW is warmer, saltier, and lighter. At these same times, large increases of apparent oxygen utilization (AOU) and potential vorticity are found at the SPMW base, consistent with SPMW ventilation to lighter densities during lower NAO index periods. Deeper and denser in the water column, the cold, fresh, and dense SAIW signature within the permanent pycnocline that was most strongly present in 1993, near the culmination of a period of high NAO index, is much reduced in 1988 and 1998. In 2003, after a prolonged period of lower NAO index, increasing influence of warmer, saltier subtropical waters is clear within the permanent pycnocline. The deep penetration of the changes implies that they are caused primarily by circulation changes resulting from NAO-associated wind shifts, but changes in air–sea heat flux could also have played a role. [Copyright &y& Elsevier]

Abstract: In this paper, we review interdecadal climatic variability in the eastern tropical Pacific Ocean. This variability dominates the climatic fluctuations in the North Pacific on scales between ENSO and the centennial trend and is commonly referred to as the Pacific Decadal Oscillation or PDO. We include a historical overview and a summary of observational work that describes the surface, tropospheric and subsurface signatures of this variability. Descriptions of interdecadal variability are incomplete at best, mostly due to limitations in the observational record. We emphasize that the well-known “ENSO-like” sea surface temperature (SST) pattern describing the PDO may not be an accurate representation. In the eastern tropical Pacific, the SST maxima are displaced north and south of the equator with larger amplitudes in the northern branch near the coast of North America, which has significant implications for the troposphere-driven circulations. Several mechanisms have been proposed to explain the PDO. We review these mechanisms and models, which capture our present level of understanding of the problem. We conclude by reporting there is little evidence of both multidecadal variability and the centennial trend in the eastern tropical Pacific. This paper is part of a comprehensive review of the oceanography of the eastern tropical Pacific. [Copyright &y& Elsevier]

A simplified coupled ocean–atmosphere model, consisting of a one-layer bidimensional ocean model and a one-layer unidimensional energy balance atmospheric model [J. Clim. 13 (2000) 232] is used to study the unstable interactions between zonal winds and ocean gyres. In a specific range of parameters, decadal variability is found. Anomalies, quite homogeneous zonally, show small-scale wavelength in latitude: perturbations emerge and grow at the southern limb of the intergyre boundary and propagate southward before decaying. The wind stress anomalies are proportional to the meridional gradient of the atmospheric temperature anomalies: this ratio acts as a positive amplification factor, as confirmed by a parameter sensitivity analysis. Assuming zonally-averaged anomalies harmonic in the meridional direction, a very simple analytical model for the perturbations is derived, based on forced Rossby wave adjustment of the western boundary current and its associated anomalous heat transport: it accounts for the scale selection, the growth and the southward propagation of sea surface temperature anomalies in the subtropical gyre. The latter is not only due to the slow advection by the mean current, but to a prevailing mechanism of self-advecting coupled oceanic and atmospheric waves, out of phase in latitude. Relevance to the observational record is discussed. [Copyright &y& Elsevier]

A newly compiled global reef database indicates that the 5–6 Myr long Frasnian (Late Devonian) metazoan reef episode had relatively low diversity compared to Middle Devonian highs (with over 200 genera of calcitic rugose and tabulate corals). Following an initial early rise after Late Givetian coral and stromatoporoid extinctions, reefs expanded for the last time during mid-Frasnian sealevel highstands, but declined markedly in the Late Frasnian (rhenana-linguiformis conodont zones), below the Frasnian/Famennian (F/F) boundary. Globally, metazoan reefs were wiped out by the end Frasnian: some Famennian reefs, while partly retaining the structure of the underlying carbonate platform, were built by cyanobacterial consortia such as Renalcis, Rothpletzella, Girvanella and Epiphyton. During the Famennian, foraminiferans with calcite walls became abundant for the first time in the Phanerozoic, adding a new dimension to carbonate platforms. Colonial rugose corals (phaceloid, cerioid and thamnasterioid modules) were absent in the early post-extinction phases up into the mid-Famennian, and very rare and non-reef-building later, but solitary deep-water Lazarus corals survived locally. Coral–sponge reefs are unknown from the 21 Myr long Famennian, also a time of very low platform carbonate production. Rare, small, isolated stromatoporoid sponge, and lithistid sponge patch reefs returned episodically during the Famennian in North America, western Europe, Australia and China: the aragonitic stromatoporoids became extinct at the end of the Famennian. During a Late Devonian tectonically very active, collisional Caledonian mountain-building phase, oceanic and atmospheric cooling, accompanied by sealevel lowstand systems, exposed most carbonate platforms, accelerating coastal erosion and karsting. This increased the amount of clastics in the shelf-slope setting, in the last 1–3 Myr prior to the F/F boundary, often burying reefs. Immediately following, there were protracted losses in nearly all major tropical shelf, benthic marine invertebrates, exceeded only by the end Permian extinctions in severity. There is no apparent link between black, organic-rich horizons and reef demise at or close to the F/F boundary. The F/F boundary not also marks the largest change from widespread flooded Early and Mid-Paleozoic continental cratons to narrow, distal shelves, but also spikes the largest known global Phanerozoic shift in atmospheric O2 enrichment, and CO2 drawdown. This threshold matched the rise of the first tropical rainforests, and expansion of terrestrial biomes on the tropical coastal lowlands formerly occupied by carbonate platforms. [Copyright &y& Elsevier]

• The area analysed is autotrophic over an annual cycle. • Marine net biological production is estimated at 19 mmol m−2 d−1 in O 2 equivalents. • Different dynamics can explain productivity peaks in different times of the year. • Water is oxygen undersaturated during the whole winter period. As part of the OSMOSIS project, a fleet of gliders surveyed the Porcupine Abyssal Plain site (Northeast Atlantic) from September 2012 to September 2013. Salinity, temperature, dissolved oxygen concentration and chlorophyll fluorescence were measured in the top 1000 m of the water column. Net community production (N) over an annual cycle using an oxygen-budget approach was compared to variations of several parameters (wind speed, mixing layer depth relative to euphotic depth, temperature, density, net heat flux) showing that the main theories (Critical Depth Hypothesis, Critical Turbulence Hypothesis, Heat-flux Hypothesis) can explain the switch between net heterotrophy to net autotrophy in different times of the year, The dynamics leading to an increase in productivity were related to shifts in regimes, such as the possible differences in nutrient concentration. The oxygen concentration profiles used for this study constitute a unique dataset spanning the entire productive season resulting in a data series longer than in previous studies. Net autotrophy was found at the site with a net production of (6.4 ± 1.9) mol m−2 in oxygen equivalents (or (4.3 ± 1.3) mol m−2 in carbon equivalents). The period exhibiting a deep chlorophyll maximum between 10 m and 40 m of depth contributed (1.5 ± 0.5) mol m−2 in oxygen equivalent to the total N. These results are greater than most previously published estimates. [ABSTRACT FROM AUTHOR]

There is a strong inter-annual and inter-decadal variability in time series of flood-related variables, such as intense precipitation, high river discharge, flood magnitude, and flood loss at a range of spatial scales. Perhaps part of this variability is random or chaotic, but it is quite natural to seek driving factors, in a statistical sense. It is likely that climate variability (atmosphere–ocean oscillation) track plays an important role in the interpretation of the variability of flood-related characteristics, globally and, even more so, in several regions. The aim of this review paper is to create an inventory of information on spatially and temporally organized links of various climate-variability drivers with variability of characteristics of water abundance reported in scientific literature for a range of scales, from global to local. The climate variability indices examined in this paper are: El Niño-Southern Oscillations (ENSO), North Atlantic Oscillations (NAO), Atlantic Multi-decadal Oscillation (AMO), and Pacific Decadal Oscillations (PDO). A meta-analysis of results from many studies reported in scientific literature was carried out. The published results were collected and classified into categories after regions, climate variability modes, as well as flood-related variables: precipitation, river flow, and flood losses. [ABSTRACT FROM AUTHOR]