Rising sea levels threaten Department of Defense (DoD) facilities, operations, and connected communities, with impacts predicted to accelerate significantly in coming decades. To support informed decision making and resilient planning, the DoD Regional Sea Level (DRSL) database provides regionalized sea level change scenarios for three future time horizons to assess vulnerability and risks at DoD sites worldwide. With the recent release of more detailed projections of extreme water levels (Fox-Kember et al. 2021, Garner et al. 2021, Sweet et al. 2022), and with the development of advanced methods for defining extreme water level (EWL) probabilities, the modeling and analysis study will result in recommendations for DRSL updates and expansions for consideration by the Coastal Assessment Regional Scenario Working Group. Two methods for projecting EWL using the TESLA model (Marra et al. 2022) and global models of storm surge and waves forced by global climate model outputs, will be compared at four total test sites, two in the Atlantic and two in the Pacific, for the purpose of improving extreme event assessments. Tools to incorporate wave effects in extreme sea levels will be demonstrated at the test sites. Mean sea level projections at sites that can be added to the Real Property Asset Database and a methodology for updating vertical land motion (VLM) rates will be developed.

A formalism for selecting VLM rates, a key contributor to regional sea level variations, will be specified using tide gauge, satellite altimetry, and global positioning system data as well as glacial isostatic adjustment models. The DRSL incorporates a regional frequency analysis (RFA) for specifying EWL statistics from nearby tide gauges. Recent updates to the RFA methodology (Sweet et al. 2020, Sweet et al. 2022) will be evaluated for possible incorporation into the DRSL. Other approaches for specifying EWLs (e.g., Anderson et al. 2019, Muis et al. 2020) will be evaluated and best estimates will be developed. A demonstration of a Total Water Level (TWL) product (combined sea level, tides, water level residuals, and wave runup) (Erikson et al. 2018, Anderson et al. 2021) will be implemented at selected sites with recommendations for potential TWL products.

The information will support resilient strategies for facilities management, emergency planning, and regional operations in a changing climate.

References:

Anderson, D. L., P. Ruggiero, F. J. Mendez, P. L. Barnard, L. H. Erikson, A. C. O'Neill, M. Merrifield, A. Rueda, L. Cagigal, and J. Marra (2021), A hybrid statistical dynamical model incorporating climate variability into future coastal total water levels for flood risk analysis, Earth’s Future, 9, e2021EF002285. https://doi.org/10.1029/2021EF002285

Anderson, D., A. Rueda, L. Cagigal, J. A. Antolinez, F. J. Mendez, and P. Ruggiero (2019), Time varying emulator for short and long-term analysis of coastal flood hazard potential, Journal of Geophysical Research: Oceans https://doi.org/10.1029/2019JC015312

Erikson, L., P. Barnard, A. O’Neill, N. Wood, J. Jones, J. Finzi-Hart, and A. Foxgrover (2018), Projected 21st century coastal flooding in the Southern California Bight. Part 2: Tools for assessing climate change driven coastal hazards and socio-economic impacts, Journal of Marine Science and Engineering, 6, 19. https://doi.org/10.3390/jmse6030076

Fox-Kemper, B., H.T. Hewitt, C. Xiao, G. Aðalgeirsdóttir, S.S. Drijfhout, T.L. Edwards, N.R. Golledge, M. Hemer, R.E. Kopp, G. Krinner, A. Mix, D. Notz, S. Nowicki, I.S. Nurhati, L. Ruiz, J.-B. Sallée, A.B.A. Slangen, and Y. Yu (2021), Ocean, Cryosphere and Sea Level Change. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [MassonDelmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press. In Press. https://www.ipcc.ch/report/ar6/wg1/

Garner, G. G., T. Hermans, R.E. Kopp, A.B.A. Slangen, T.L. Edwards, A. Levermann, S. Nowikci, M.D. Palmer, C. Smith, B. Fox-Kemper, H.T. Hewitt, C. Xiao, G. Aðalgeirsdóttir, S.S. Drijfhout, T.L.Edwards, N.R. Golledge, M. Hemer, R.E. Kopp, G. Krinner, A. Mix, D. Notz, S. Nowicki, I. S. Nurhati, L. Ruiz, J-B. Sallée, Y. Yu, L. Hua, T. Palmer, and B. Pearson (2021). IPCC AR6 Sea-Level Rise Projections. Version 20210809. PO.DAAC, CA, USA. Dataset accessed [2021-09-01]. https://podaac.jpl.nasa.gov/announcements/2021-08-09-Sea-levelprojections-from-the-IPCC-6th

Marra, J.J. et al. (2022), Advancing Best Practices for the Analysis of the Vulnerability of Military Installations in the Pacific Basin to Coastal Flooding under a Changing Climate – RC-2644: Final Report for the U.S. Department of Defense Strategic Environmental Research and Development Program. June 1, 2022. 543pp

Muis, S., M. Irazoqui Apecechea, J. Dullaart, J. de Lima Rego, K.S. Madsen, J. Su, K. Yan, and M. Verlaan (2020), A high-resolution global dataset of extreme sea levels, tides, and storm surges, including future projections, Front. Mar. Sci. 7:263. doi: 10.3389/fmars.2020.00263

Sweet, W. V., A. S. Genz, J. Obeysekera, and J. J. Marra (2020), A regional frequency analysis of tide gauges to assess Pacific coast flood risk. Frontiers in Marine Science, 7, 883. https://doi.org/10.3389/fmars.2020.581769

Sweet, W. V., B. D. Hamlington, R. E. Kopp, C. P. Weaver, P. L. Barnard, D. Bekaert, W. Brooks, M. Craghan, G. Dusek, T. Frederikse, G. Garner, A. S. Genz, J. P. Krasting, E. Larour, D. Marcy, J. J. Marra, J. Obeysekera, M. Osler, M. Pendleton, D. Roman, L. Schmied, W. Veatch, K. D. White, and C. Zuzak (2022), Global and Regional Sea Level Rise Scenarios for the United States: Up- dated Mean Projections and Extreme Water Level Probabilities Along U.S. Coastlines. NOAA Technical Report NOS 01. National Oceanic and Atmospheric Administration, National Ocean Service, Silver Spring, MD, 111 pp. https://oceanservice.noaa.gov/hazards/sealevelrise/noaa-nos- techrpt01-global regional-SLRscenarios-US.pdf