The goal of this project was to: (a) archive the relevant AR5 model output data for the southwest region; (b) downscale daily temperature and precipitation to 12 X 12 km cell spatial resolution over the Southwest; (c) assess the precision (degree of agreement) of the simulated models; (d) assess the direction and magnitude of change in projections between AR4 and AR5, as well as assess projections of key extreme climatic events (i.e., extreme drought, extreme seasonal precipitation, extreme high and low temperature events); and (e) assess critical ecosystem impacts (i.e., climate water deficit and fire; hydrological condition of major river systems; impacts on highly valued species).
Analysis of Downscaled Climate Simulations and Projections and Their Use in Decision Making for the Southwest
To understand potential climate change impacts on ecosystems, water resources, and numerous other natural and managed resources, climate change data and projections must be downscaled from coarse global climate models to much finer resolutions and more applicable formats. This project conducted comparative analyses to better understand the accuracy and properties of these downscaled climate simulations and climate-change projections. Interpretation, guidance and evaluation, including measures of uncertainties, strengths and weaknesses of the different methodologies for each simulation, can enable potential users with the necessary information to select and apply the models.
To better understand climate variability and possible climate change effects on surface hydrology, water resources and related natural and human managed systems in the western U.S., with emphasis on California.
In the southwestern United States, droughts of 10 or more years are projected to become more frequent by 2100. It also is projected that there will be fewer wet days per year, with more precipitation falling on those wet days. Such climatic extremes can strongly affect wild animals and plants, ecosystems, and humans. In the Southwest, more frequent and intense storms may negatively affect protected species in coastal salt marshes; changes in the timing and amount of precipitation could lead to increases in fuel loads; and increasingly humid heat waves could lead to higher incidence of heat-related illness among visitors to national parks. This project will improve understanding of climate extremes and their potential...
Natural climate variability can obscure or enhance long-term trends in experienced weather due to climate change. This can happen temporarily on timescales of a season to several years to a decade or two. Natural variability is poorly described and attributed to specific causes, contributing to uncertainty and misunderstandings about the nature of climate change that stakeholders and resource managers attempt to anticipate. There exists, therefore, a need to clarify the magnitude and causality of natural climate variability. This connection needs to be explained for locally-experienced weather and particularly for daily extreme events, whose seasonal behavior impacts both resources and imagination. Conversely, it...
In the Southwestern U.S., rising temperatures and changing precipitation patterns are resulting in changes such as more frequent and severe wildfires and prolonged drought. Natural resource managers striving to make decisions in the face of these changing conditions can benefit from information on past, present, and future climate. While an array of climate assessments are available, it is unclear how useful or relevant this information is for resource management decision-making in the Southwest. This project sought to identify the types of environmental information that resource managers in the Southwest need to make climate-related management decisions. To meet this goal, researchers first assessed the degree...