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Regional Climate Change Effects: Useful Information for Transportation Agencies

Acronyms and Glossary


BCCR BCM2.0: Bjerknes Centre for Climate Research (BCCR) Bergen Climate Model (BCM) Version 2, Norway

CCSM3.0: National Center for Atmospheric Research (NCAR) Community Climate System Model, Version 3.0

CGCM3.1: Canadian Centre for Climate Modelling and Analysis Coupled General Circulation Model, Version 3.1, Canada

CNRM: Centre National de Recherches Météorologiques, France

CCSP: Climate Change Science Program

CIG: Climate Impacts Group

CSIRO: Commonwealth Scientific and Industrial Research Organization, Australia

DOT: Department of Transportation

FHWA: Federal Highway Administration

GHG: Greenhouse gas

GCM: General Circulation Model

GFDL CM 2.0: Geophysical Fluid Dynamics Laboratory Climate Model, Version 2.0

GFDL CM 2.1: Geophysical Fluid Dynamics Laboratory Climate Model, Version 2.1

GISS AOM: Goddard Institute for Space Studies, Atmosphere-Ocean Model

HadCM3: Hadley Centre Coupled Model, Version 3, United Kingdom

HadGEM1: Hadley Centre Global Environmental Model, Version 1, United Kingdom

IAP FGOALS-g1.0: Institute of Atmospheric Physics (IAP), Flexible Global Ocean Atmosphere Land System (FGOALS) model, Gridpoint Version 1.0, China

INM-CM3.0: Institute of Numerical Mathematics Coupled Model, Version 3.0, Russia

IPCC: Intergovernmental Panel on Climate Change

IPCC AR4: Intergovernmental Panel on Climate Change Fourth Assessment Report

IPSL CM4: L'Institut Pierre-Simon Laplace Coupled Model, Version 4, France

MIROC3.2(hires): Model for Interdisciplinary Research on Climate, High Resolution Version, Center for Climate System Research, Japan

MIROC3.2(medres): Model for Interdisciplinary Research on Climate, Medium Resolution Version, Center for Climate System Research, Japan

MIUB ECHO-G: Meteorological Institute University of Bonn (MIUB), ECHO-G, Germany

MPI ECHAM: Max Planck Institute for Meteorology (MPI), ECHAM model, Version 5, Germany

MRI CGCM 2.3.2a: Meteorological Research Institute (MRI), Coupled General Circulation Model (CGCM), Version 2.3.2a, Japan

NCAR: National Center for Atmospheric Research

NCDC: National Climatic Data Center, National Oceanic & Atmospheric Administration (NOAA)

NRC: National Research Council

PCM: Parallel Climate Model

SAP: Synthesis and Assessment Product

SRES: Special Report Emission Scenarios

USGCRP: United States Global Change Research Program


This information is summarized from a collection of sources (USGCRP 2009, CCSP 2008a, CCSP 2009b, IPCC 2007a, Lutgens and Tarbuck 2007, Ahrens 2007).

1-in-20 weather event
An extreme weather event (e.g., extreme temperature, heat wave, rainfall, storms, storm surges) of a severity that has a probability of occurring only once every 20 years (i.e., a 5% chance of occurring in any given year, or with a severity at the 95th percentile of similar events). However, an event occurring in one year does not preclude the event from occurring the following year or even the following week.
Annual mean temperature
The arithmetic mean, or average, of daily temperatures for a given year.
Climate change effects
Changes in climate variables that are brought about by climate change.
Climate models
A model that incorporates the principles of physics, chemistry, and biology into a mathematical model of climate.
Climate stressors
For the purposes of this report, climate stressors are climate effects that affect the design, construction, operation, and/or maintenance of transportation infrastructure.
Climate variables
Physical characteristics of climate, such as temperature, humidity, level of precipitation, frequency of storms, sea-level rise, that can be quantified using climate models.
Diurnal temperature range
The variation in temperature between the minimum (lowest) temperature and the maximum (highest) temperature for a given day.
Mathematical techniques that have been developed to transform the projected climate effects of global climate models to a regional scale. Global climate models partition the world into large grids of cells that hide regional details; downscaling is used to provide climate effect results at a finer resolution. Downscaling techniques generally can be classified as either statistical downscaling or dynamic downscaling.
Downscaling, statistical
Statistical downscaling determines a relationship between the climate model output of a climate effect for a past 30- to 40-year time period and the observed climate effect for the same time period. This relationship is then used to downscale the projected climate model output for that particular climate effect. This approach is best when the determined relationship is robust over time; that is, the processes governing the climate effect remain fixed with time. This may not always be an appropriate method for downscaling precipitation projections (NECIA 2006).
Downscaling, dynamical
Dynamical downscaling uses a regional model equipped with small-scale processes and local topography. The climate model data are used as inputs around the boundaries of the regional model. This technique allows for capturing the effects of local topography. Though this process tends to be expensive and time-consuming, it does include dynamical changes in response to large-scale forcing. Given the investment for this approach, dynamical downscaled studies generally provide projections based on the results from only a single climate model.
Effects typology matrix
A tool to summarize projected climate effects by: geographic location, time horizon, emission scenario, and climate variable. The effects typology matrix developed in this report can be found in Appendix C.
Emissions scenarios
Hypothetical scenarios of future greenhouse gas emissions profiles.
Time horizon, End-of-century
For the purposes of this report, End-of-century refers to a 2070 to 2100 time horizon.
The process through which a liquid is transformed into a gas.
Extreme cold events
An extreme weather event characterized by very cold temperatures. The exact definition of what is meant by an extreme cold event can vary. For example, extreme cold events may be defined as temperatures below the 5th percentile for a given region.
Extreme weather events
Weather events that exhibit very severe conditions such as intense levels of precipitation or high levels of wind and can cause significant damage. These events can include intense tornado-breeding convective storms, well-developed mid-latitude cyclones (such as a nor'easter), and tropical storms (particularly ones that develop into hurricanes).
Extreme heat day
The maximum temperature for a given day exceeds 90°F (in some studies, this term is defined as the maximum temperature for a given day exceeds 100°F).
Extreme heat event
Has multiple definitions of duration and intensity, and generally is a relative measure to local climate conditions. The Centers for Disease Control defines it as a temperature 10°F or more above the average high temperature for a region, lasting several weeks. Other sources define the event by the apparent temperature (determined through a calculation based on maximum temperature and humidity) reaching above a 1-in-20-year event (or an event that has a 5% chance of occurring per year).
Fall months
September, October, and November (SON)
Freeze-thaw cycle
Period of time that elapses between freezing and thawing conditions.
Heat waves
Three or more days where daily heat index exceeds 90°F.
High Temperature Day
At or above the 95th percentile among current daily temperature records (Diffenbaugh et al 2005).
Humidity, relative
The ratio of air's water vapor content to its water vapor capacity.
A tropical cyclonic storm having minimum winds of 74 miles per hour (64 knots, or 119 kilometers per hour).
Interglacial period
Period of warm global average temperatures between two glacial periods within an ice age. The Earth is currently in an interglacial period called the Holocene.
Jet stream, polar
A swift, westerly airstream in the upper troposphere that meanders in relatively narrow belts and is a result of the boundary between two surface air masses: warm southern air and cold northern air. The polar jet stream is usually located between 9 to 12 km above the Earth's surface (altitude).
Emissions scenario; low emissions scenario (B1)
The low emissions scenario referenced in this report corresponds with the B1 emission scenario developed by the IPCC (2000). This scenario describes a "convergent world" with low population growth and rapid changes in the global economy toward service and information sectors. It assumes reductions in material intensity, and the introduction of clean and resource-efficient technologies. (IPCC 2000)
Time horizon, Mid-century
For the purposes of this report, Mid-century refers to a 2040 to 2070 time horizon.
Emissions scenario; moderately high "business as usual" emission scenario (A2)
The moderately high, or "business as usual" emission scenario referenced in this report corresponds with the A2 emission scenario developed by the IPCC (2000). "Business as usual" refers to an emission scenario that is assumed to occur without any effort to reduce greenhouse gas emissions from present practices. The A2 scenario describes a "fragmented" future with less cooperation between world governments, high population growth, and regionally oriented economic development that results in slow per capita economic growth and technological change. (IPCC 2000)
Multi-model ensemble
A collection of results from several different climate models. An ensemble of results allows scientists to investigate the range of uncertainty in the results produced from climate models (i.e., to quantify a degree of model uncertainty).
Time horizon, Near-term
For the purposes of this report, near-term refers to a 2010 to 2040 time horizon.
Non-climate stressors
For the purposes of this report, non-climate stressors are effects that are unrelated to climate that affect the design, construction, operation, and maintenance of transportation infrastructure.
Ocean circulation
The water in the Earth's ocean moves dynamically around the globe, driven by motion of the Earth's atmosphere with the large-scale oceanic circulation pattern (thermohaline circulation) influencing small-scale circulations.
Ocean salinity
The concentration of salt within ocean waters, which affects water density and surface water absorption of carbon dioxide.
The study of past climates on Earth. According to the NASA Goddard Institute of Space Studies, the study of past climates provide insight into how the Earth's atmosphere, oceans, biosphere, and cryosphere has evolved and responded to past climatic forcing (GISS, 2009).
Precipitation, duration
A measure describing the length of time of precipitation.
Precipitation, frequency
A measure of how often precipitation occurs.
Precipitation, intensity
A measure of the rate of precipitation, or the amount of precipitation that falls within a given time period. Typically measured as inches of precipitation per day.
In this report, precipitation refers to all forms including rain, snow, or sleet.
Rain/snow line
The location within a storm where the precipitation shifts from rain to snow.
Sea-level, mean
Average relative sea level over a long enough time period to average out wave/tide variability (such as a month or year).
Sea-level rise, relative
The sea level measured by a tide gauge with respect to the land upon which it is situated (IPCC 2007a).
Sea-level rise, global
World-wide average rise in sea level. A number of factors contribute to this rise, such as thermal expansion and ice/glacier melting (CCSP 2009).
Solar radiation
Wavelike energy emitted by the Sun that possesses heat.
Spatial resolution
The level of detail provided by a climate model in assessing climate effects. Spatial resolution refers to the size of the grid used to partition the area being studied. The model calculates climate variable results for each cell within the grid.
Spring months
March, April, May (MAM)
Local land mass lowers due to plate tectonics. This term is considered when determining relative sea-level rise.
Summer months
June, July, August (JJA
Thermal expansion (of oceans)
The increase in molecular motion of ocean water in response to warming, where this motion leads to an increase in volume space for the same number of molecules. Generally considered when estimating how sea level will change as temperatures warm.
Uncertainty in model projections covers three main contributors: natural variability, choice of emission scenarios, and climate models. Uncertainty is further discussed in Section 2.
Uncertainty; likely range (for the projection of a given climate variable)
The likely range is computed by first determining the standard deviation above and below the average for each of the two scenarios examined in this report. Assuming the data are well represented by a Gaussian distribution, the likely range represents about 68% of the values extending from the 15th percentile to the 85th percentile. Then, the minimum and maximum of these four values (i.e., two from each scenario) are defined as the likely range. The range is a measure of the differences (and uncertainty) associated with the models that were used as well as the uncertainty of future emission rates.
Uncertainty; mean range (for the projection of a given climate variable)
The mean range is the average of all simulations in the lower emission scenario (B1) and the average of all of the simulations in the higher emission scenario (A2). It is a simple measure of the central tendency of the projections and the uncertainty associated with future greenhouse gas emission rates.
Uncertainty; very likely range (for the projection of a given climate variable)
The very likely range is computed the same way as the likely range, except that two standard deviations are used instead of one. Assuming the data are well represented by a Gaussian distribution, the very likely range represents about 95% of the values extending from the 2.2nd percentile to the 97.8th percentile.
Local rising of land masses through plate tectonics and/or thermal buoyancy. Uplift is considered when determining local sea-level rise.
Vertical land motion
Shifting of land masses through plate tectonics and/or thermal buoyancy. This motion is considered when determining local sea-level rise.
Winter months
December, January, February(DJF)
Updated: 3/27/2014
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