This final report summarizes the project’s major accomplishments in research, training and product development. We have accomplished our primary goals of this project. With our research we contribute significant new information to the monitoring and assessment of ongoing climatic changes in Hawai‘i. Over the last decades the general trends in the wet season rainfall was negative and given the modeled climate scenarios from CMIP3 and CMIP5, it is very likely these trends are going to continue in the 21st century. In this research project, we improved the spatial information content of our statistical downscaling method through the introduction of the Rainfall Atlas of Hawai‘i station data sets and the use of improved large‐scale climate predictor information. Furthermore, the statistical downscaling (SD) of the CMIP5 multi‐model ensemble data updated the future rainfall projections to the latest estimated emissions scenarios (RCP4.5 and RCP8.5) and the newest climate model results for the 21st century. In summary of all the results, we find that the negative trend towards less wet‐season (November‐April) precipitation is very likely to continue in the 21st century. Most affected from this trend are the arid and semiarid regions of the Islands. This drying trend during the rain season could be an important climate stress factors for terrestrial ecosystems in arid and semiarid regions in Hawai‘i.
