KATRINA M. FANDRICH

As climate models continue to improve, the demand for more accurate climate projections is increasing. However, natural climate variability poses a limit to the confidence in regional climate change projections, particularly for the near-term. The goal of this project is to examine the Pacific Decadal Oscillation (PDO) and anthropogenic climate change for their impacts on near-term rainfall projections for the Hawaiian Islands.

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In this study, the moisture budget for the Hawaiian Islands is analyzed in order to explain projected hydrological changes for the near term future (2026-2035). The analysis is based on 20 dynamically-downscaled simulations of member runs from the CESM1 Large Ensemble. The Weather Research and Forecasting model (WRF) is used for direct downscaling, taking into account the simulated changes in natural climate variability (e.g., Pacific Decadal Oscillation). The integrated MFC is first decomposed into advection and divergence components. The integrated MFC is then decomposed into dynamic and thermodynamic components (i.e., changes due to perturbations in the mean wind and humidity fields), Of primary interest is which terms are driving the near-term hydrological changes in the downscaled simulations and what is the hydrological response to the anthropogenic forcing,

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LINKING THE NORTH PACIFIC JET TO HAWAIIAN RAINFALL DISTURBANCES

During winter (Nov-Apr), Kona Lows and other rainfall disturbances (e.g., fronts) contribute significant sources of rainfall to the Hawaiian Islands, oftentimes leading to extreme rainfall and flooding (Otkin and Martin, 2004; Longman et al. 2021). Previous work has demonstrated that the interannual variabiltiy of wintertime Hawaiian rainfall is strongly influenced by largescale weather and climate phenomena of the North Pacific including El Nino Southern Oscillation (ENSO), the Pacific North American (PNA) pattern, the Pacific Decadal Oscillation (PDO), and the North Pacific jet (NPJ) (Chu et al. 1993; Chu and Chen 2005; O'Connor et al. 2015; Frazier et al. 2017). However, a study that directly links North Pacific jet variability with Hawaiian rainfall disturbance types has yet to be conducted. Consequently, the goal of this study is to better understand the relationship between the North Pacific jet variability, Hawaiian rainfall disturbances, and natural climate modes. In this work, we utilize a self-organizing maps approach to answer the question:

What NPJ structures are associated with wintertime Hawaiian rainfall disturbances?

 

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PRESENTATIONS:

AGU - December 2022 - Poster Presentation

AGU - December 2021 - Virtual Poster Presentation

Intnl. Tropical Islands Water Conference - April 2021 - Virtual Talk

AMS - January 2020 - Poster Presentation

AGU - December 2020 - Virtual Poster Presentation

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PUBLICATIONS:

Fandrich, K. M., O. Elison Timm, C. Zhang, and T. Giambelluca, in prep: Decomposition of near-term (2026-2035) hydrological changes for the Hawaiian Islands region using dynamical downscaling. JGR Atmospheres.

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Fandrich, K. M., O. Elison Timm, C. Zhang, and T. Giambelluca (2022) : Dynamical downscaling of near-term (2026-2035) climate variability and change for the main Hawaiian Islands. JGR Atmospheres. https://doi.org/10.1029/2021JD035684

M.S. Thesis

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