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Stony coral tissue loss disease (SCTLD) is a highly contagious disease, causing mass coral mortalities in the Atlantic/Caribbean since 2014. In Puerto Rico, SCTLD was first reported in 2019 off the east coast, spreading to the north-central region by early February 2021. Benthic surveys were conducted at Cueva del Indio (CI) and Peñón de Mera (PM) off Arecibo to (1) quantify coral species-specific SCTLD prevalence using four 10 × 1-m2 belt transects and (2) acquire time-series photo and video surveys to illustrate the impact of SCTLD, to evaluate coral species-specific susceptibilities, and estimate the timing of onset in Arecibo. A total of 650 corals in six species (Pseudodiploria strigosa, P. clivosa, Montastraea cavernosa, Siderastrea siderea, Orbicella annularis, Porites astreoides) were recorded inside the belt transects at both sites. SCTLD prevalence varied between 54% (P. strigosa) and 35.5% (M. cavernosa) at CI, and between 87.5% (S. siderea) and 25% (O. faveolata) at PM. Photo/video surveys revealed that SCTLD caused partial mortality in 11 species and full mortality in P. strigosa, P. clivosa, S. siderea, M. cavernosa, and Dendrogyra cylindrus. The results are discussed in view of prior research and contribute to understanding the spread and impact of SCTLD around Puerto Rico, which can be applied to predict its spread to other regions in the Caribbean. 

Drought is a prominent feature of Hawaiʻi’s climate. However, it has been over 30 years since the last comprehensive meteorological drought analysis, and recent drying trends have emphasized the need to better understand drought dynamics and multi-sector effects in Hawaiʻi. Here, we provide a comprehensive synthesis of past drought effects in Hawaiʻi that we integrate with geospatial analysis of drought characteristics using a newly developed 100-year (1920–2019) gridded Standardized Precipitation Index (SPI) dataset. The synthesis examines past droughts classified into five categories: Meteorological, agricultural, hydrological, ecological, and socioeconomic drought. Results show that drought duration and magnitude have increased significantly, consistent with trends found in other Pacific Islands. We found that most droughts were associated with El Niño events, and the two worst droughts of the past century were multi-year events occurring in 1998–2002 and 2007–2014. The former event was most severe on the islands of O’ahu and Kaua’i while the latter event was most severe on Hawaiʻi Island. Within islands, we found different spatial patterns depending on leeward versus windward contrasts. Droughts have resulted in over $80 million in agricultural relief since 1996 and have increased wildfire risk, especially during El Niño years. In addition to providing the historical context needed to better understand future drought projections and to develop effective policies and management strategies to protect natural, cultural, hydrological, and agricultural resources, this work provides a framework for conducting drought analyses in other tropical island systems, especially those with a complex topography and strong climatic gradients. 

This paper discusses the design and implementation of the Hawai‘i Rainfall Analysis and Mapping Application (HI-RAMA) decision support tool. HI-RAMA provides researchers and community stakeholders interactive access to and visualization of hosted historical and near-real-time monthly rainfall maps and aggregated rainfall station observational data for the State of Hawai‘i. The University of Hawai‘i Information Technology Services Cyberinfrastructure team in partnership with members of the Hawai‘i Established Program to Stimulate Competitive Research (EPSCoR) ‘Ike Wai project team developed this application as part of the ‘Ike Wai Gateway to support water sustainability research for the state of Hawai‘i. This tool is designed to provide user-friendly access to information that can reveal the impacts of climate changes related to precipitation so users can make data-driven decisions. 

Abstract Gridded monthly rainfall estimates can be used for a number of research applications, including hydrologic modeling and weather forecasting. Automated interpolation algorithms, such as the “autoKrige” function in R, can produce gridded rainfall estimates that validate well but produce unrealistic spatial patterns. In this work, an optimized geostatistical kriging approach is used to interpolate relative rainfall anomalies, which are then combined with long-term means to develop the gridded estimates. The optimization consists of the following: 1) determining the most appropriate offset (constant) to use when log-transforming data; 2) eliminating poor quality data prior to interpolation; 3) detecting erroneous maps using a machine learning algorithm; and 4) selecting the most appropriate parameterization scheme for fitting the model used in the interpolation. Results of this effort include a 30-yr (1990–2019), high-resolution (250-m) gridded monthly rainfall time series for the state of Hawai‘i. Leave-one-out cross validation (LOOCV) is performed using an extensive network of 622 observation stations. LOOCV results are in good agreement with observations (R²= 0.78; MAE = 55 mm month⁻¹; 1.4%); however, predictions can underestimate high rainfall observations (bias = 34 mm month⁻¹; −1%) due to a well-known smoothing effect that occurs with kriging. This research highlights the fact that validation statistics should not be the sole source of error assessment and that default parameterizations for automated interpolation may need to be modified to produce realistic gridded rainfall surfaces. Data products can be accessed through the Hawai‘i Data Climate Portal (HCDP;http://www.hawaii.edu/climate-data-portal). Significance StatementA new method is developed to map rainfall in Hawai‘i using an optimized geostatistical kriging approach. A machine learning technique is used to detect erroneous rainfall maps and several conditions are implemented to select the optimal parameterization scheme for fitting the model used in the kriging interpolation. A key finding is that optimization of the interpolation approach is necessary because maps may validate well but have unrealistic spatial patterns. This approach demonstrates how, with a moderate amount of data, a low-level machine learning algorithm can be trained to evaluate and classify an unrealistic map output.