Developing fast and accurate surrogates for physics-based coastal and ocean models is an urgent need due to the coastal flood risk under accelerating sea level rise, and the computational expense of deterministic numerical models. For this purpose, we develop the first digital twin of Earth coastlines with new physics-informed machine learning techniques extending the state-of-art Neural Operator. As a proof-of-concept study, we built Fourier Neural Operator (FNO) surrogates on the simulations of an industry-standard flood and ocean model (NEMO). The resulting FNO surrogate accurately predicts the sea surface height in most regions while achieving upwards of 45x acceleration of NEMO. We delivered an open-source \textit{CoastalTwin} platform in an end-to-end and modular way, to enable easy extensions to other simulations and ML-based surrogate methods. Our results and deliverable provide a promising approach to massively accelerate coastal dynamics simulators, which can enable scientists to efficiently execute many simulations for decision-making, uncertainty quantification, and other research activities.

The marine environment represents a large and important resource for coastal communities around the world. However, the marine environment also increasingly presents hazards that can have a large negative impact on the community. One important marine hazard stems from storms and their accompanying surges. This can lead to coastal flooding, particularly when surge and astronomical high tides align, with resultant impacts ranging from destruction of property to saline degradation of agricultural land and coastal erosion.

Differential tectonic activity is a key factor responsible for variable relative sea-level (RSL) changes during the late Holocene in the Adriatic. Here, we compare reconstructions of RSL from the central-eastern Adriatic coast of Croatia with ICE-7G_NA (VM7) glacial-isostatic model RSL predictions to assess underlying driving mechanisms of RSL change during the past similar to 2700 years. Local standardized published sea-level index points (n = 23) were combined with a new salt-marsh RSL reconstruction and tide-gauge measurements. We enumerated fossil foraminifera from a short salt-marsh sediment core constrained vertically by modern foraminiferal distributions, and temporally by radiometric analyses providing sub-century resolution within a Bayesian age-depth framework. We modelled changes in RSL using an Errors In-Variables Integrated Gaussian Process (EIV-IGP) model with full consideration of the available uncertainty. Previously established index points show RSL rising from -1.48 mat 715 BCE to -1.05 m by 100 CE at 0.52 mm/yr (-0.82-1.87 mm/yr). Between 500 and 1000 CE RSL was -0.7 m below present rising to -0.25 mat 1700 CE. RSL rise decreased to a minimum rate of 0.13 mm/yr (-0.37-0.64 mm/yr) at similar to 1450 CE. The salt-marsh reconstruction shows RSL rose similar to 0.28 m since the early 18th century at an average rate of 0.95 mm/yr. Magnitudes and rates of RSL change during the twentieth century are concurrent with long-term tide-gauge measurements, with a rise of similar to 1.1 mm/yr. Predictions of RSL from the ICE-7G_NA (VM7) glacial-isostatic model (-0.25 mat 715 BCE) are consistently higher than the reconstruction (-1.48 mat 715 BCE) during the Late Holocene suggesting a subsidence rate of 0.45 +/- 0.6 mm/yr. The new salt-marsh reconstruction and regional index points coupled with glacial-isostatic and statistical models estimate the magnitude and rate of RSL change and subsidence caused by the Adriatic tectonic framework. (C) 2018 Elsevier Ltd. All rights reserved.

An analysis of dead benthic foraminiferal assemblages and associated environmental variables is presented to establish the controls on species distribution and zonation on two macrotidal saltmarshes in the Mersey estuary with the aim of evaluating the use of foraminifera in reconstructing past sea levels. The combined results from five contemporary transects from two sites illustrate that where there is a sufficient elevational range, foraminifera distribution and zonation shows a good relationship with altitude, with a high-to-middle marsh zone characterised by Haplophragmoides wilberti , Jadammina macrescens, and Miliammina fusca, and a low marsh zone composed of similar agglutinated species with calcareous species including Brizalina spp., Elphidium spp., and Haynesina spp. Cluster analysis and partial Redundancy Analysis (pRDA) reveals that the elevational control decreases with respect to other environmental variable inter-correlations when the sampling elevation range is reduced. It is proposed that this is a key issue for macrotidal environments when the contemporary sampling range represents a small proportion of the spring tidal range (i.e. <10%). Limiting the contemporary dataset to agglutinated species only, a tidal level transfer function can be obtained which offers acceptable predictability and precision (r2jack = 0.79, RMSEPjack = 0.13 m) for the reconstruction of past sea level.

Salt-marsh foraminifera serve as proxy sea-level indicators due to a quantifiable relationship with elevation in the contemporary environment. In this paper, we document the distribution of salt-marsh foraminifera from two microtidal sites, Jadrtovac and Blace, along the Adriatic coast of Croatia and assess their suitability as proxies for elevation in transfer-function-based reconstructions of sea level, which is not yet established for the Mediterranean region. The assemblages are dominated by typical salt-marsh agglutinated taxa, Jadammina macrescens and Trochammina inflata, and the calcareous taxa Ammonia spp. and Quinqueloculina spp. Quantitative analyses revealed that the assemblages are divided into three faunal zones, which are elevation dependent, and that the assemblage dominated by J. macrescens and T. inflata extends to higher elevations in the intertidal frame. The training set was used to develop a tidal-level transfer function using linear regression due to the short environmental gradients observed. The model predicts sea level with a precision of +/- 0.08 m. This study highlights the strong potential of salt-marsh foraminifera in reconstructing RSL trends for the Mediterranean region, where studies of past sea-level have previously been restricted to other indicators.

The main component of the Global Sea Level Observing System (GLOSS) is the GLOSS Core Network (GCN) of 290 sea level stations. The present definition of the GCN (the definition is modified every few years) is called GLOSS10. In 2012 a new GLOSS implementation plan was developed to update technical standards for GLOSS tide gauge stations, as well as describing the basic terms and obligations for Member States participating in GLOSS. The British Oceanographic Data Centre (BODC) and the Permanent Service for Mean Sea Level (PSMSL) run the GLOSS Delayed Mode Data Centre jointly. It is responsible for assembling, quality controlling and distributing the "final" version of GLOSS sea level data sets and their supporting metadata, as well as carrying out data archaeology on historical analogue sea level records, preserving them in digital form. It also maintains the GLOSS Station Handbook and GLOSS website.

Sea-level changes on a wide range of time and space scales. This article considers changes in mean sea level, that is, sea level averaged over a sufficient period of time to remove fluctuations associated with surface waves, tides, and individual storm surge events. Changes in sea level changes over the last hundred years or so and on how it might change over the next one hundred years are or particular interest. However, to understand these changes requires consideration of sea level since the last glacial maximum 20,000 years ago. The longer-term implications of changes in the Earth's climate arising from changes in atmospheric greenhouse gas concentrations are also considered.

Editors note: For easy download the posted pdf of the State of the Climate for 2012 is a very low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.

The Greenland, West and East Antarctic ice sheets are the largest reservoirs of freshwater on the planet. As such, they have contributed to sea level change over geological and recent times. They gain mass through accumulation (snowfall) and lose it by surface ablation (mostly ice melt) and outflow at their marine boundaries, either to a floating ice shelf, or directly to the ocean through iceberg calving. Increases in accumulation cause global mean sea level to fall, while increases in surface ablation and outflow cause it to rise. Fluctuations in these mass fluxes depend on a range of processes, both within the ice sheet and without, in the atmosphere and oceans. Over the course of this century, however, sources of mass loss appear set to exceed sources of mass gain, so that a continuing positive contribution to global sea level can be expected. This FAQ summarizes current research on the topic and provides indicative magnitudes for the various end-of-century (2081-2100 with respect to 1986-2005) sea level contributions from the full assessment, which are reported as the two-in-three probability level across all emission scenarios.

Sea-level rise remains one of the most pressing societal concerns relating to climate change. A significant proportion of the global population, including many of the world's large cities, are located close to the coast in potentially vulnerable regions such as river deltas. The Permanent Service for Mean Sea Level (PSMSL) continues to evolve and provide global coastal sea-level information and products that help to develop our understanding of sea-level and land motion processes. Its work aids a range of scientific research, not only in long-term change, but also in the measurement and understanding of higher frequency variability such as storm surges and tsunamis. The PSMSL has changed considerably over the past 10 years, and the aim of this paper is to update the community about these changes as well as provide an overview of our continuing work.

Large-scale climate patterns influenced temperature and weather patterns around the globe in 2011. In particular, a moderate-to-strong La Nina at the beginning of the year dissipated during boreal spring but reemerged during fall. The phenomenon contributed to historical droughts in East Africa, the southern United States, and northern Mexico, as well the wettest two-year period (2010-11) on record for Australia, particularly remarkable as this follows a decade-long dry period. Precipitation patterns in South America were also influenced by La Nina. Heavy rain in Rio de Janeiro in January triggered the country's worst floods and landslides in Brazil's history.The 2011 combined average temperature across global land and ocean surfaces was the coolest since 2008, but was also among the 15 warmest years on record and above the 1981-2010 average. The global sea surface temperature cooled by 0.1 degrees C from 2010 to 2011, associated with cooling influences of La Nina. Global integrals of upper ocean heat content for 2011 were higher than for all prior years, demonstrating the Earth's dominant role of the oceans in the Earth's energy budget. In the upper atmosphere, tropical stratospheric temperatures were anomalously warm, while polar temperatures were anomalously cold. This led to large springtime stratospheric ozone reductions in polar latitudes in both hemispheres. Ozone concentrations in the Arctic stratosphere during March were the lowest for that period since satellite records began in 1979. An extensive, deep, and persistent ozone hole over the Antarctic in September indicates that the recovery to pre-1980 conditions is proceeding very slowly.Atmospheric carbon dioxide concentrations increased by 2.10 ppm in 2011, and exceeded 390 ppm for the first time since instrumental records began. Other greenhouse gases also continued to rise in concentration and the combined effect now represents a 30% increase in radiative forcing over a 1990 baseline. Most ozone depleting substances continued to fall. The global net ocean carbon dioxide uptake for the 2010 transition period from El Nino to La Nina, the most recent period for which analyzed data are available, was estimated to be 1.30 Pg C yr(-1), almost 12% below the 29-year long-term average.Relative to the long-term trend, global sea level dropped noticeably in mid-2010 and reached a local minimum in 2011. The drop has been linked to the La Nina conditions that prevailed throughout much of 2010-11. Global sea level increased sharply during the second half of 2011.Global tropical cyclone activity during 2011 was well-below average, with a total of 74 storms compared with the 1981-2010 average of 89. Similar to 2010, the North Atlantic was the only basin that experienced above-normal activity. For the first year since the widespread introduction of the Dvorak intensity-estimation method in the 1980s, only three tropical cyclones reached Category 5 intensity level-all in the Northwest Pacific basin.The Arctic continued to warm at about twice the rate compared with lower latitudes. Below-normal summer snowfall, a decreasing trend in surface albedo, and above-average surface and upper air temperatures resulted in a continued pattern of extreme surface melting, and net snow and ice loss on the Greenland ice sheet. Warmer-than-normal temperatures over the Eurasian Arctic in spring resulted in a new record-low June snow cover extent and spring snow cover duration in this region. In the Canadian Arctic, the mass loss from glaciers and ice caps was the greatest since GRACE measurements began in 2002, continuing a negative trend that began in 1987. New record high temperatures occurred at 20 m below the land surface at all permafrost observatories on the North Slope of Alaska, where measurements began in the late 1970s. Arctic sea ice extent in September 2011 was the second-lowest on record, while the extent of old ice (four and five years) reached a new record minimum that was just 19% of normal.On the opposite pole, austral winter and spring temperatures were more than 3 degrees C above normal over much of the Antarctic continent. However, winter temperatures were below normal in the northern Antarctic Peninsula, which continued the downward trend there during the last 15 years. In summer, an all-time record high temperature of -12.3 degrees C was set at the South Pole station on 25 December, exceeding the previous record by more than a full degree. Antarctic sea ice extent anomalies increased steadily through much of the year, from briefly setting a record low in April, to well above average in December. The latter trend reflects the dispersive effects of low pressure on sea ice and the generally cool conditions around the Antarctic perimeter.

An exercise in 'data archaeology' at Ascension Island has provided an estimate of sea level change between 1955 and 2001.5 (the mid-point of a recent dataset spanning 1993-2009). That average trend of 0.93 mm y(-1) (SE 0.69) compares to a larger rate during 1993-2009 itself of 2.55 (SE 0.13) and 2.07 (SE 0.30) mm y(-1) from tide gauge and altimeter data respectively, suggesting a recent acceleration in sea level rise. An ocean model and steric height datasets have been used for comparison to the measurements, with the conclusion that the acceleration was probably at least partly due to a steric height increase. This exercise is based on only one month of historical tide gauge data and is admittedly on the useful limit for long-term sea level studies. In addition, it is unfortunate that the tide gauge benchmark installed in 1955 has disappeared, even if one can estimate its height relative to modern marks. Nevertheless, the study does provide information of interest to climate studies, enables limits to be inferred on the real changes, and provides background information for other coastal studies. Most importantly, it is intended as a demonstration of the value of similar exercises where short historical records exist.

Several large-scale climate patterns influenced climate conditions and weather patterns across the globe during 2010. The transition from a warm El Niño phase at the beginning of the year to a cool La Niña phase by July contributed to many notable events, ranging from record wetness across much of Australia to historically low Eastern Pacific basin and near-record high North Atlantic basin hurricane activity. The remaining five main hurricane basins experienced below- to well-below-normal tropical cyclone activity. The negative phase of the Arctic Oscillation was a major driver of Northern Hemisphere temperature patterns during 2009/10 winter and again in late 2010. It contributed to record snowfall and unusually low temperatures over much of northern Eurasia and parts of the United States, while bringing above-normal temperatures to the high northern latitudes. The February Arctic Oscillation Index value was the most negative since records began in 1950. The 2010 average global land and ocean surface temperature was among the two warmest years on record. The Arctic continued to warm at about twice the rate of lower latitudes. The eastern and tropical Pacific Ocean cooled about 1°C from 2009 to 2010, reflecting the transition from the 2009/10 El Niño to the 2010/11 La Niña. Ocean heat fluxes contributed to warm sea surface temperature anomalies in the North Atlantic and the tropical Indian and western Pacific Oceans. Global integrals of upper ocean heat content for the past several years have reached values consistently higher than for all prior times in the record, demonstrating the dominant role of the ocean in the Earth's energy budget. Deep and abyssal waters of Antarctic origin have also trended warmer on average since the early 1990s. Lower tropospheric temperatures typically lag ENSO surface fluctuations by two to four months, thus the 2010 temperature was dominated by the warm phase El Niño conditions that occurred during the latter half of 2009 and early 2010 and was second warmest on record. The stratosphere continued to be anomalously cool. Annual global precipitation over land areas was about five percent above normal. Precipitation over the ocean was drier than normal after a wet year in 2009. Overall, saltier (higher evaporation) regions of the ocean surface continue to be anomalously salty, and fresher (higher precipitation) regions continue to be anomalously fresh. This salinity pattern, which has held since at least 2004, suggests an increase in the hydrological cycle. Sea ice conditions in the Arctic were significantly different than those in the Antarctic during the year. The annual minimum ice extent in the Arctic—reached in September—was the third lowest on record since 1979. In the Antarctic, zonally averaged sea ice extent reached an all-time record maximum from mid-June through late August and again from mid-November through early December. Corresponding record positive Southern Hemisphere Annular Mode Indices influenced the Antarctic sea ice extents. Greenland glaciers lost more mass than any other year in the decade-long record. The Greenland Ice Sheet lost a record amount of mass, as the melt rate was the highest since at least 1958, and the area and duration of the melting was greater than any year since at least 1978. High summer air temperatures and a longer melt season also caused a continued increase in the rate of ice mass loss from small glaciers and ice caps in the Canadian Arctic. Coastal sites in Alaska show continuous permafrost warming and sites in Alaska, Canada, and Russia indicate more significant warming in relatively cold permafrost than in warm permafrost in the same geographical area. With regional differences, permafrost temperatures are now up to 2°C warmer than they were 20 to 30 years ago. Preliminary data indicate there is a high probability that 2010 will be the 20th consecutive year that alpine glaciers have lost mass. Atmospheric greenhouse gas concentrations continued to rise and ozone depleting substances continued to decrease. Carbon dioxide increased by 2.60 ppm in 2010, a rate above both the 2009 and the 1980–2010 average rates. The global ocean carbon dioxide uptake for the 2009 transition period from La Niña to El Niño conditions, the most recent period for which analyzed data are available, is estimated to be similar to the long-term average. The 2010 Antarctic ozone hole was among the lowest 20% compared with other years since 1990, a result of warmer-than-average temperatures in the Antarctic stratosphere during austral winter between mid-July and early September.