Significant changes have been observed in temperature and rainfall in Hawai‘i over the past century. In the case of rainfall trends, it is still not clear whether these changes can be attributed to global warming. The main objective of this project is to test the null hypothesis: that observed regional precipitation changes in recent decades are consistent with natural, internally-generated climate variability. To address this question, researchers will apply methods applied in formal Detection and attribution (DA) studies in climate sciences. A key challenge is to find objective, quantitative estimates of how unusual the observed trends are compared with trend-like features caused by internal climate variability in the Pacific. In this project, DA methods will be applied to address the following questions that have so far been not fully answered for the regional climate changes observed in Hawai‘i:
Can the observed long-term changes in Hawaiian rainfall be attributed to anthropogenic forcing?
What are the individual contributions from greenhouse gas forcing, aerosol forcing, and natural forcing factors (solar, volcanic) to rainfall variability and long-term trends?
How much uncertainty can be expected in future climate change projections due to the influence of internal variability?
At the beginning of the project, PIs will establish a two-way dialogue to ensure that stakeholders are informed about the key concepts and potential outcomes of the research. In return, Pacific RISA team members will learn from stakeholders about the relevant climatic (and non-climatic) information that they integrate into their workflow and decision-making. This will allow stakeholders to inform the RISA team about which climatic information they consider most relevant for their planning/decisions and policy-making in connection with climate change adaptation and Loss and Damage assessment. Stakeholders can use the products (maps, data, and publications) produced by this project to obtain information on the causes of observed precipitation trends in the Hawaiian Islands. Together with currently available future change scenarios, stakeholders can compare historical precipitation trends with and without anthropogenic forcing and re-evaluate the potential risk for continued drought trends or increased risk in high-intensity rainfall events.
A landslide along Kuhio Highway on Kauai’s North Shore (DLNR, 2018). A high-intensity rainfall event in 2018 caused major flooding and damage, temporarily cut off the North Shore from the rest of the island, and caused millions of dollars in damage.
Research Team Thomas Giambelluca, Director, Water Resources Research Center and Professor, Geography, University of Hawai‘i Oliver-Elison Timm, Associate Professor, Atmospheric & Environmental Sciences, University at Albany
Kristen Sanfilippo, Department of Geography and Environment, UH Mānoa
Katrina Fandrich, Department of Atmospheric and Environmental Sciences, SUNY Albany
References Compo, G. P., Whitaker, J. S., Sardeshmukh, P. D., Matsui, N., Allan, R. J., Yin, X., . . . Worley, S. J. (2011). The Twentieth Century Reanalysis Project. Quarterly Journal of the Royal Meteorological Society, 137(654), 1-28. doi: 10.1002/qj.776.
Giambelluca, T. W., Diaz, H. F., & Luke, M. S. A. (2008). Secular temperature changes in Hawai‘i. Geophysical Research Letters, 35(12). doi: 10.1029/2008gl034377.
Gillett, N. P., Shiogama, H., Funke, B., Hegerl, G., Knutti, R., Matthes, K., Santer, B. D., Stone, D., & Tebaldi, C. (2016). Detection and Attribution Model Intercomparison Project (DAMIP), Geoscientific Model Development Discussions. doi:10.5194/gmd-2016-74.
Intergovernmental Panel on Climate Change. (2013). Evaluation of detection and attribution methodologies. Chapter 10, Section 10.2 in Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.), Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (pp. 1535). Cambridge and New York: Cambridge University Press. doi:10.1017/CBO9781107415324.
Resilient and sustainable Pacific Island communities using climate information to manage risks and support practical decision-making about climate variability and change.
Trends in Hawaiian Rainfall
Significant changes have been observed in temperature and rainfall in Hawai‘i over the past century. In the case of rainfall trends, it is still not clear whether these changes can be attributed to global warming. The main objective of this project is to test the null hypothesis: that observed regional precipitation changes in recent decades are consistent with natural, internally-generated climate variability. To address this question, researchers will apply methods applied in formal Detection and attribution (DA) studies in climate sciences. A key challenge is to find objective, quantitative estimates of how unusual the observed trends are compared with trend-like features caused by internal climate variability in the Pacific. In this project, DA methods will be applied to address the following questions that have so far been not fully answered for the regional climate changes observed in Hawai‘i:
At the beginning of the project, PIs will establish a two-way dialogue to ensure that stakeholders are informed about the key concepts and potential outcomes of the research. In return, Pacific RISA team members will learn from stakeholders about the relevant climatic (and non-climatic) information that they integrate into their workflow and decision-making. This will allow stakeholders to inform the RISA team about which climatic information they consider most relevant for their planning/decisions and policy-making in connection with climate change adaptation and Loss and Damage assessment. Stakeholders can use the products (maps, data, and publications) produced by this project to obtain information on the causes of observed precipitation trends in the Hawaiian Islands. Together with currently available future change scenarios, stakeholders can compare historical precipitation trends with and without anthropogenic forcing and re-evaluate the potential risk for continued drought trends or increased risk in high-intensity rainfall events.
Partners
Honolulu Board of Water Supply, Hawai‘i Commission on Water Resource Management, USGS, Alaska Climate Adaptation Science Center (AK-CASC)
Research Team
Thomas Giambelluca, Director, Water Resources Research Center and Professor, Geography, University of Hawai‘i
Oliver-Elison Timm, Associate Professor, Atmospheric & Environmental Sciences, University at Albany
Kristen Sanfilippo, Department of Geography and Environment, UH Mānoa
Katrina Fandrich, Department of Atmospheric and Environmental Sciences, SUNY Albany
References
Compo, G. P., Whitaker, J. S., Sardeshmukh, P. D., Matsui, N., Allan, R. J., Yin, X., . . . Worley, S. J. (2011). The Twentieth Century Reanalysis Project. Quarterly Journal of the Royal Meteorological Society, 137(654), 1-28. doi: 10.1002/qj.776.
Frazier, A., & Giambelluca, T. (2017). Spatial trend analysis of Hawaiian rainfall from 1920 to 2012. International Journal of Climatology, 37(5), 2522–2531.
Giambelluca, T. W., Diaz, H. F., & Luke, M. S. A. (2008). Secular temperature changes in Hawai‘i. Geophysical Research Letters, 35(12). doi: 10.1029/2008gl034377.
Gillett, N. P., Shiogama, H., Funke, B., Hegerl, G., Knutti, R., Matthes, K., Santer, B. D., Stone, D., & Tebaldi, C. (2016). Detection and Attribution Model Intercomparison Project (DAMIP), Geoscientific Model Development Discussions. doi:10.5194/gmd-2016-74.
Helweg, D.A., Keener, V., & Burgett, J.M. (2016). Report from the workshop on climate downscaling and its application in high Hawaiian Islands, September 16–17, 2015: U.S. Geological Survey Open-File Report 2016–1102, 25 p., https://doi.org/10.3133/ofr20161102.
Helweg, D., Keener, V. (2017). Applications of Climate Downscaling in the Main Hawaiian Islands: Balancing Climate Modelers’ Products and Impact Modelers’ Expectations, https://doi.org/10.21429/C9CW4R.
Intergovernmental Panel on Climate Change. (2013). Evaluation of detection and attribution methodologies. Chapter 10, Section 10.2 in Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.), Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (pp. 1535). Cambridge and New York: Cambridge University Press. doi:10.1017/CBO9781107415324.
Kagawa-Viviani, A.K., & Giambelluca, T.W. (2020). Patterns of near surface air temperatures across the Hawaiian Islands, 1905-2017. Journal of Geophysical Research-Atmospheres, 125(2). doi: 10.1029/2019JD031571.
McKenzie, M. M., Giambelluca, T. W., & Diaz, H. F. (2019). Temperature trends in Hawaiʻi: A century of change, 1917–2016. International Journal of Climatology, 39(10), 3987-4001. doi: 10.1002/joc.6053.
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Resilient and sustainable Pacific Island communities using climate information to manage risks and support practical decision-making about climate variability and change.
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