Assumption - condition or factor that is accepted as true or as certain to happen, without proof (Oxford University Press, 2013). In the context of alternative future scenarios, each scenario is an internally coherent body of assumptions about how the future will unfold.
CMIP5 - A phase of the World Climate Research Programme’s Coupled Model Intercomparison Project (CMIP). CMIP is a worldwide effort to establish a set of standard experimental protocols for the use of general circulation computer models (also called global climate models), or GCMs, in the development of climate scenarios. Essentially, the CMIP project is an attempt by the world’s climate modelers to improve the performance of GCMs, standardize methods of model evaluation, and make GCM outputs directly comparable.
Driver - a factor which causes a particular phenomenon to happen or develop (Oxford University Press, 2013). In WW2100 modeling scenarios climate change and population and income change are considered external drivers, forces taht are determined outside of the model and can be varied between scenarios.
Downscaling - A means to convert or translate the coarse resolution of global climate model (GCM) grids (which are as large as 375 km, roughly 233 miles, to a side) down to a finer resolution, which for WW2100 was about 4 km, roughly 2.5 miles. This is done to account for the details of local topography and local climate. This adjustment is needed in the Pacific Northwest, which has a complex mountainous topography that does not appear in a detailed form in the GCMs.
Envision - is a GIS-based tool for scenario-based community and regional integrated planning and environmental assessments developed by John Bolte and colleagues at Oregon State University. It provides a platform for integrating a variety of spatially explicit models of landscape change processes and production for conducting alternative futures analysis.
Gaussian filter - an algorithm used in time-series analysis to smooth data. The Gaussian filter has an effect similar to the ‘running average’.
Institutions - humanly-devised rules and organizations. These include laws, property rights (such as water rights), regulations (such as reservoir rule curves), and also operational rules for public management such as those for dams, forests, highways (e.g., reservoir fill curve, speed limits). The concept includes formal institutions as well as cultural norms, ethics and moral rules.
Integrated Decision Unit (IDU) - an attributed polygon representing a portion of the landscape; a spatial geometry to model both human decisions and successional processes in space. There are 164,892 polygons in the IDU layer, covering the nearly 30,000 km2 (11500 mi2) extent of the Willamette River Basin.Most IDUs cover an area of between 2 and 700 hectares (5 and 1730 acres).
Leaf area index (LAI) -- a dimensionless quantity that characterizes plant canopies. It is defined as the one-sided green leaf area per unit ground surface area (LAI = leaf area / ground area, m2 / m2) in broadleaf canopies. As LAI increases, evapotranspiration also increases.
Model – a simplified representation of a real system or process (Konikow & Bredehoeft, 1992).
Private Actor/Individual – Farmers, consumers, interest groups, society generally outside the public sector. Includes “interest groups” or “stakeholders” such as farm lobby, land developers, etc.
Public agent – Individuals whose job it is to enforce laws and manage public resources/assets on behalf of society (dam managers, water masters, water utility staff, state troopers). They also often have valuable expertise about the public institutions they implement or enforce.
Sankey diagram - Plot showing flow of energy or mass where the thickness of the lines are proportional to the flow in that part of the system. They take their name from Sankey (1898).
Scenario - A scenario is a coherent, internally consistent and plausible description of a possible future state of the world. It is not a forecast; rather, each scenario is one alternative image of how the future can unfold. A projection may serve as the raw material for a scenario, but scenarios often require additional information (e.g., about baseline conditions). A set of scenarios is often adopted to reflect, as well as possible, the range of uncertainty in projections. Other terms that have been used as synonyms for scenario are "characterization", "storyline", and "construction" (Intergovernmental Panel on Climate Change, 2011).
Sensitivity analysis - assessment of how variations in specific factors (input, parameter, state, model structure, etc.) affect the output response of a model (Liu et al, 2008).
Snow Water Equivalent (SWE) - a measure of snowpack that can be thought of as the depth of water that would theoretically result if you melted the entire snowpack instantaneously.
[SWE] ÷ [Density] = Snow Depth
Sub-model - In WW2100 we use this term to describe computer models that “plug into” and share data within Willamette Envision. In some cases, these are pre-existing models that have been adapted for the project. In other cases, they are new models that were developed specifically for WW2100.
Reference Case scenario - A model of future expected trends in population and income growth, existing policies and institutions, and a mid-range climate change scenario. The interactions of these elements in the Reference scenario is a base case, which we use as a comparator for other scenarios.
Urban Growth Boundary (UGB) - a land use planning line drawn around a city or metropolitan area that determines where urban development can take place; UGBs were implemented in Oregon following the Oregon Land Use Act of 1973.
Water scarcity - (1) Formal definition developed by project scientists (Jaeger et al., 2013): The marginal value of a unit of water, or the value of an incremental increase or decrease in water use. This definition applies to a specific use, location, and point in time.
Water year - Akin to the fiscal year in accounting, the water year is one year beginning on October 1 and ending on September 30. This water year is used in Oregon and many parts of the US West. The abbreviation for water year is ‘WY’. WY2020 begins Oct. 1, 2019 and extends to Sep. 30, 2020.