scholarly journals Probabilistic Sea Level Rise Flood Projections Using a Localized Ocean Reference Surface

2022 ◽  
Author(s):  
Noah A. Paoa-Kannegiesser ◽  
Charles H. Fletcher ◽  
Tiffany R. Anderson ◽  
Makena Coffman
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ocean Surface ◽  
Reanalysis Data ◽  
Ocean Modeling ◽  
Regional Ocean Modeling System ◽  
Flood Depth ◽  
Study Sites ◽  
Elevation Model ◽  
Height Component

Abstract Projecting sea level rise (SLR) impacts requires defining ocean surface variability as a source of uncertainty. We analyze data from a Regional Ocean Modeling System (ROMS) reanalysis for the region surrounding the main Hawaiian Islands to incorporate the ocean surface uncertainty in mapping SLR flood probabilities. By analyzing the ocean surface height component of the ROMS reanalysis, we create an ocean surface reference (ORS) as a proxy for MHHW. We model the NOAA Intermediate, Intermediate-high and High regional SLR scenarios for the years 2050 and 2100 at three field sites around Oʻahu; Waikīkī, Hauʻula, Haleʻiwa. We calculate a probability density function (PDF) by convolving the PDF of water level derived from the ROMS reanalysis data with the PDF of error associated with a digital elevation model of the study sites. The resulting joint-PDF of flood depth allows us to create two types of probability-based flood projections: (1) Maps illustrating varying flood depths for a given probability threshold and, (2) maps illustrating varying probability for a specific flood depth. We compare 80% probability flood projections using our ORS approach to projections using the TCARI grid, the standard NOAA method. We highlight the importance of uncertainty and user-defined probability in identifying pixels that function as tipping points distinguishing flooding styles.

scholarly journals Divergence of seafloor elevation and sea level rise in coral reef ecosystems

2017 ◽  
Vol 14 (6) ◽  
pp. 1739-1772 ◽  
Author(s):  
Kimberly K. Yates ◽  
David G. Zawada ◽  
Nathan A. Smiley ◽  
Ginger Tiling-Range
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Sea Level Rise ◽  
Sea Level ◽  
Anthropogenic Impacts ◽  
Regional Scale ◽  
Coastal Hazards ◽  
Carbonate Production ◽  
Coral Reef Ecosystems ◽  
Study Sites

Abstract. Coral reefs serve as natural barriers that protect adjacent shorelines from coastal hazards such as storms, waves, and erosion. Projections indicate global degradation of coral reefs due to anthropogenic impacts and climate change will cause a transition to net erosion by mid-century. Here, we provide a comprehensive assessment of the combined effect of all of the processes affecting seafloor accretion and erosion by measuring changes in seafloor elevation and volume for five coral reef ecosystems in the Atlantic, Pacific, and Caribbean over the last several decades. Regional-scale mean elevation and volume losses were observed at all five study sites and in 77 % of the 60 individual habitats that we examined across all study sites. Mean seafloor elevation losses for whole coral reef ecosystems in our study ranged from −0.09 to −0.8 m, corresponding to net volume losses ranging from 3.4  ×  106 to 80.5  ×  106 m3 for all study sites. Erosion of both coral-dominated substrate and non-coral substrate suggests that the current rate of carbonate production is no longer sufficient to support net accretion of coral reefs or adjacent habitats. We show that regional-scale loss of seafloor elevation and volume has accelerated the rate of relative sea level rise in these regions. Current water depths have increased to levels not predicted until near the year 2100, placing these ecosystems and nearby communities at elevated and accelerating risk to coastal hazards. Our results set a new baseline for projecting future impacts to coastal communities resulting from degradation of coral reef systems and associated losses of natural and socioeconomic resources.

scholarly journals New elevation data triple estimates of global vulnerability to sea-level rise and coastal flooding

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Scott A. Kulp ◽  
Benjamin H. Strauss
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
High Tide ◽  
Water Levels ◽  
Low Carbon ◽  
Digital Elevation ◽  
Elevation Data ◽  
Global Mean Sea Level ◽  
Elevation Model ◽  
Global Mean

Abstract Most estimates of global mean sea-level rise this century fall below 2 m. This quantity is comparable to the positive vertical bias of the principle digital elevation model (DEM) used to assess global and national population exposures to extreme coastal water levels, NASA’s SRTM. CoastalDEM is a new DEM utilizing neural networks to reduce SRTM error. Here we show – employing CoastalDEM—that 190 M people (150–250 M, 90% CI) currently occupy global land below projected high tide lines for 2100 under low carbon emissions, up from 110 M today, for a median increase of 80 M. These figures triple SRTM-based values. Under high emissions, CoastalDEM indicates up to 630 M people live on land below projected annual flood levels for 2100, and up to 340 M for mid-century, versus roughly 250 M at present. We estimate one billion people now occupy land less than 10 m above current high tide lines, including 230 M below 1 m.

scholarly journals The trough-system algorithm and its application to spatial modeling of Greenland subglacial topography

2014 ◽  
Vol 55 (67) ◽  
pp. 115-126 ◽  
Author(s):  
Ute C. Herzfeld ◽  
Brian W. McDonald ◽  
Bruce F. Wallin ◽  
Phillip A. Chen ◽  
Helmut Mayer ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Algebraic Topology ◽  
Dynamic Models ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Dynamics ◽  
Subglacial Topography ◽  
Radar Measurements ◽  
Elevation Model

AbstractDynamic ice-sheet models are used to assess the contribution of mass loss from the Greenland ice sheet to sea-level rise. Mass transfer from ice sheet to ocean is in a large part through outlet glaciers. Bed topography plays an important role in ice dynamics, since the acceleration from the slow-moving inland ice to an ice stream is in many cases caused by the existence of a subglacial trough or trough system. Problems are that most subglacial troughs are features of a scale not resolved in most ice-sheet models and that radar measurements of subglacial topography do not always reach the bottoms of narrow troughs. The trough-system algorithm introduced here employs mathematical morphology and algebraic topology to correctly represent subscale features in a topographic generalization, so the effects of troughs on ice flow are retained in ice-dynamic models. The algorithm is applied to derive a spatial elevation model of Greenland subglacial topography, integrating recently collected radar measurements (CReSIS data) of the Jakobshavn Isbræ, Helheim, Kangerdlussuaq and Petermann glacier regions. The resultant JakHelKanPet digital elevation model has been applied in dynamic ice-sheet modeling and sea-level-rise assessment.

scholarly journals Permanent Meanders in the California Current System

2008 ◽  
Vol 38 (8) ◽  
pp. 1690-1710 ◽  
Author(s):  
L. R. Centurioni ◽  
J. C. Ohlmann ◽  
P. P. Niiler
Keyword(s):  
Sea Level ◽  
Current System ◽  
California Current ◽  
Ocean Model ◽  
Ocean Modeling ◽  
Surface Velocity ◽  
Regional Ocean Modeling System ◽  
Near Surface ◽  
Geostrophic Velocity ◽  
California Current System

Abstract Surface Velocity Program (SVP) drifter data from 1987 through 2005; Archiving, Validation, and Interpretation of Satellite Oceanographic data (AVISO) sea level anomalies; and NCEP reanalysis winds are used to assemble a time-averaged map of the 15-m-deep geostrophic velocity field in the California Current System seaward of about 50 km from the coast. The wind data are used to compute the Ekman currents, which are then subtracted from the drifter velocity measurements. The resulting proxy for geostrophic velocity anomalies computed from drifters and from satellite sea level measurements are combined to form an unbiased mean geostrophic circulation map. The result shows a California Current System that flows southward with four permanent meanders that can extend seaward for more than 800 km. Bands of alternating eastward and westward zonal currents are connected to the meanders and extend several thousand kilometers into the Pacific Ocean. This observed time-mean circulation and its associated eddy energy are compared to those produced by various high-resolution OGCM solutions: Regional Ocean Modeling System (ROMS; 5 km), Parallel Ocean Program model (POP; 1/10°), Hybrid Coordinate Ocean Model (HYCOM; 1/12°), and Naval Research Laboratory (NRL) Layered Ocean Model (NLOM; 1/32°). Simulations in closest agreement with observations come from ROMS, which also produces four meanders, geostrophic time-mean currents, and geostrophic eddy energy consistent with the observed values. The time-mean ageostrophic velocity in ROMS is strongest within the cyclonic part of the meanders and is similar to the ageostrophic velocity produced by nonlinear interaction of Ekman currents with the near-surface vorticity field.

scholarly journals Impact of sea level rise and shoreline changes in the tropical island ecosystem of Andaman and Nicobar region, India

2021 ◽  
Author(s):  
mageswaran thangaraj ◽  
Sachithanandam V ◽  
Sridhar R ◽  
Manik Mahapatra ◽  
R Purvaja ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Sea Level Rise ◽  
Sea Level ◽  
Remote Sensing Data ◽  
Data Sets ◽  
Andaman Island ◽  
Shoreline Changes ◽  
Digital Elevation ◽  
Analysis System ◽  
Elevation Model

Abstract We report here a four decades of shoreline changes and possible sea level rise (SLR) impact on landuse/landcover (LULC) in Little Andaman Island by using remote sensing (RS) and GIS techniques. A total of six remote sensing data sets covering years between 1976 and 2018 were used to understand the shoreline changes. Moreover, a Digital Shoreline Analysis System (DSAS) was used to estimate short- and long- term shoreline changes from ArcGIS environment. Besides, the Island vulnerability due to SLR was studied through using digital elevation model (DEM). As a result of Sumatra earthquake (2004), the results were showed a significant variation in shorline upliftment and subsidence. The land subsidence was noticed in the range of 1042-3077 ha with sea level rise between 1 and 5 m. Hence, we conclude that Little Andaman Island is vulnerable to SLR and overwhelm low elvation coastal zone.

scholarly journals Digital elevation model generation using UAV-SfM photogrammetry techniques to map sea-level rise scenarios at Cassino Beach, Brazil

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Deivid Cristian Leal-Alves ◽  
Jair Weschenfelder ◽  
Miguel da Guia Albuquerque ◽  
Jean Marcel de Almeida Espinoza ◽  
Marlize Ferreira-Cravo ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Digital Elevation Model ◽  
Model Generation ◽  
Digital Elevation ◽  
Elevation Model

Grid-based global coastal zone datasets for coastal impact analysis

2020 ◽  
Author(s):  
Daniel Lincke
Keyword(s):  
Land Use ◽  
Sea Level Rise ◽  
Sea Level ◽  
Coastal Zone ◽  
Urban Areas ◽  
Impact Analysis ◽  
Rocky Shores ◽  
Management Options ◽  
Elevation Model ◽  
Natural Boundaries

<p><span>Global coastal impact and adaptation analysis in the context of climate change induced sea-level rise needs precise and standardized datasets. Here, such datasets and their construction are presented. Starting from a high-resolution global digital elevation model, the coastline is extracted with taking into account river mouths and lagoons taken from a global surface water dataset. The global low-elevation coastal zone (LECZ) is derived by determining all grid cells hydrological connected to the coastline. Recent surge-data is combined with sea-level rise scenarios to partition the global LECZ into local floodplains. Latest socio-economic and land-use data is used to partition and classify these local floodplains. As local impacts and adaptation responses are not spatially uniform, but depend on a range of conditions including: i) biophysical conditions such as natural boundaries between floodplains (e.g. hills, rocks, etc.) and coastal geomorphology (e.g. sandy versus rocky shores), ii) technical conditions such as existing flood protection infrastructure (e.g. dike rings in the Netherlands), and ii) socio-economic conditions such as administrative boundaries, land use and urban extent (e.g. rural versus urban areas), latest land-use, beach and wetland datasets are used to partition the coastline of each floodplain into a network of coastline segments which can be used for assessing local shoreline management options. </span></p><p><span>The generated datasets contain about 1.6 million km of coastline distributed over 87,600 islands. The LECZ comprises 3.14 million km² and partitioning this LECZ with surge and sea-level rise data into floodplains for coastal impact modelling finds about 221,800 floodplains with at least 0.05 km² area. </span></p>

scholarly journals The Vorticity Balance of the Ocean Surface in Hawaii from a Regional Reanalysis

2015 ◽  
Vol 45 (2) ◽  
pp. 424-440 ◽  
Author(s):  
Joao Marcos Azevedo Correia de Souza ◽  
Brian Powell ◽  
Alma Carolina Castillo-Trujillo ◽  
Pierre Flament
Keyword(s):  
Ocean Surface ◽  
Ocean Modeling ◽  
Surface Currents ◽  
Regional Ocean Modeling System ◽  
The North ◽  
System A ◽  
Representation Error ◽  
Zonal Wavenumber ◽  
Ocean Surface Currents ◽  
Regional Reanalysis

AbstractThe ocean surface vorticity budget around the Hawaiian Islands is examined using an 18-month model reanalysis generated using four-dimensional variational state estimation with all available observations (satellite, in situ, and high-frequency radio). To better resolve the ocean surface currents and reduce the representation error of the radio-measured surface currents, this study developed a new vertical scheme for the Regional Ocean Modeling System. A new, detailed description of the ocean surface vorticity is created, revealing a region dominated by cyclonic (anticyclonic) vorticity to the north (south) of the mean position of the Hawaii Lee Countercurrent. Advection of vorticity is the primary process that transports the vorticity generated in the lee of the islands by the wind wake. In this island lee, the zonal wavenumber spectra show a cascade of vorticity/energy from the submesoscale toward the larger scales. Latitudinal differences in the advection of vorticity spectra indicate the propagation of a first baroclinic mode Rossby wave in the region dominated by anticyclonic vorticity to the west of the island of Hawaii, while the region dominated by cyclonic vorticity is disrupted by the wake of the smaller islands.

scholarly journals The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

2012 ◽  
Vol 9 (10) ◽  
pp. 14689-14708 ◽  
Author(s):  
M. L. Kirwan ◽  
J. A. Langley ◽  
G. R. Guntenspergen ◽  
J. P. Megonigal
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Sea Level Rise ◽  
Chesapeake Bay ◽  
Sea Level ◽  
Decay Rates ◽  
Tidal Marshes ◽  
Study Sites ◽  
Rates Of Decay ◽  
The Impact

Abstract. The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

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