An observed station dataset that includes adjustments to address shifts due to changes in instruments and observing procedures. In some cases the observations from several stations are joined to generate long time series. This data set is available at daily, monthly, seasonal and annual time frequencies for a number of different variables.
The variables available on ClimateData.ca are daily precipitation, minimum, maximum and mean daily temperature. By removing shifts in the data which are not due to changes in the weather, this data set can be used for the analysis of long term climate trends.
Value that represents the difference between the value for a given year or season from the normal of the reference period.
Changes in climate that are caused by human actions and activities.
Australian National University Spline (ANUSPLIN) software. An interpolation method for constructing gridded observational datasets. This method uses a multi-dimensional curve fitting technique, along with latitude, longitude and elevation to ensure that the gridded data are spatially continuous. ANUSPLIN is used to produce NRCANmet, which was used to downscale and bias-adjust global climate model outputs to create CanDCS-U5 and CanDCS-U6, the main climate projection datasets on ClimateData.ca. More information can be found in the About ANUSPLIN Page.
The assessment reports of the IPCC (Intergovernmental Panel on Climate Change)are comprehensive reports on the state of the knowledge on climate change, its consequences and potential impacts and response options. Between 1990 and 2023, the IPCC has published six comprehensive assessment reports reviewing the latest climate science. The sixth (and most recent) assessment report was published in completion in March 2023. New assessment reports are published roughly every 6 years.
Atmospheric rivers are relatively long, meandering plumes of water vapor often originating over the tropical oceans that bring sustained, heavy precipitation
Average total precipitation amount (mm/day), greater than 1mm/day, during wet days.
The climate during the reference period, see definition for reference period.
BCCAQv2 is a statistical downscaling methodology developed at the Pacific Climate Impacts Consortium and is used for downscaling global climate model projections, in particular, temperature and precipitation. It is a univariate method which downscales one variable at a time. This methodology was used to produce the CanDCS-U5 and CanDCS-U6 datasets on ClimateData.ca. Learn more: About BCCAQv2.
Methods which reduce the overall bias in observational data or climate model output. Examples include linear regression and quantile mapping.
BCCA is a bias correction approach for climate model output which captures the spatial structure of climate by using a combination of daily large-scale historical analogues (locations which experience statistically similar climate conditions). It is used in addition to Quantile Delta Mapping (QDM) in the combined method, BCCAQv2.
See Bias adjustment.
Designing buildings with the climate zone of the region in mind. There are 6 Climate Zones a building in Canada can be in; 4, 5, 6, 7a, 7b and 8. Zone 4 is the warmest zone, and so buildings here typically require less insulation compared to buildings in Zone 8, the coldest zone. More info can be found in the Learning Zone.
CanSIPSv3 is a seasonal prediction system developed by Environment and Climate Change Canada for seasonal forecasting over periods ranging from months to a year. It includes two climate models: CanESM5 and GEM5.2-NEMO. To produce seasonal forecasts, an ensemble containing 20 simulations from each of these two models is used.
The Canadian Downscaled Climate Scenarios-Multivariate dataset for CMIP6 (Phase 6 of the Coupled Model Intercomparison Project). CanDCS-M6 data were downscaled using multivariate statistical techniques (MBCn), meaning that two (or more) climate variables are downscaled concurrently preserving the relationships between these variables. Visit the CanDCS-M6 About Page for more details.
The Canadian Downscaled Climate Scenarios-Univariate dataset for CMIP6 (Phase 5 of the Coupled Model Intercomparison Project). CanDCS-U5 was downscaled using univariate downscaling techniques, i.e., each variable is downscaled independently. CanDCS-U5 was downscaled using the Bias Correction/Constructed Analogues with Quantile mapping reordering version 2 (BCCAQv2) procedure. Visit the CanDCS-U5 About Page for more details.
The Canadian Downscaled Climate Scenarios-Univariate dataset for CMIP6 (Phase 6 of the Coupled Model Intercomparison Project). CanDCS-U6 was downscaled using univariate downscaling techniques, i.e., each variable is downscaled independently. CanDCS-U6 was downscaled using the Bias Correction/Constructed Analogues with Quantile mapping reordering version 2 (BCCAQv2) procedure. Visit the CanDCS-U6 About Page for more details.
Climate is the long term statistics of weather. It includes, for example, the averages, variability, and extremes of weather for a particular place calculated over a period of at least 30 years. More info can be found in the Learning Zone.
A set of temperature/precipitation values at all points in a given space at a given instant. Gridded data products represent temperature and precipitation fields.
An organization that supplies climate information to users. The roles of these organizations may include providing historical climate data, running climate simulations, and tailoring their outputs to suit the needs of individual users.
A limit within a climate system, or its forcing, beyond which the behaviour of the system is qualitatvely changed into a different state.
Climate zones are a spatial or regional climate classification system based on certain climate characteristics. The definitions of climate zones can be based on different input variables and can be designed for specific use sectors. The well known Koeppen climate zones are based on temperature and precipitation. ClimateData.ca uses building climate zones which are designed for the building sector. More info about building climate zones can be found in the Learning Zone.
A regional climate services hub for Alberta, Manitoba and Saskatchewan, based in Winnipeg, MB, providing regionally relevant climate information for effective planning and policy making. More info can be found on the ClimateWest website.
A regional climate services hub for New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland and Labrador, based in Sackville, NB, providing regionally relevant climate information for effective planning and policy making. More info can be found on the CLIMAtlantic website.
Weather observations taken between 06:01 UTC (01:01 EST) on Day 1 and 06:00 UTC (01:00 EST) on Day 2. This specific time period ensures that maxima and minima in temperature are captured. Observational stations in Canada which have hourly measurements report daily statistics using the climatological day.
Coupled Model Intercomparison Project. CMIP is a coordinated climate modeling exercise involving climate-modeling groups from around the world. CMIP has provided a standard experimental protocol for producing and studying the output of many different global climate models. The output from CMIP ensemble experiments is used to inform international climate assessment reports, such as those from the IPCC. CMIP5 is comprised of 40 global climate models, and CMIP6 is comprised of 100 global climate models. CMIP6 models generally have increased complexity and resolution, therefore improving model accuracy, especially in mountainous regions. CMIP7 is currently in development. More information can be found in the CMIP6 FAQ.
Coarse climate models have a lower resolution when compared with higher resolution models. Relatively coarse models typically have a resolution of 250km.
The Coldest Day describes the lowest nighttime temperature in the selected time period. In general, the coldest day of the year occurs during the winter months. More info can be found in the variable section of ClimateData.ca.
Cooling degree days give an indication of the amount of air conditioning that may be required to maintain comfortable conditions in a building during warmer months. A threshold temperature of 18°C is used and for any day when the mean temperature exceeds this value, cooling degree days are accrued. So, if the daily mean temperature on a given day is 24°C, then 6 cooling degree days are accrued for this day. More info can be found in the variable section of ClimateData.ca.
CRIM (Centre de recherche informatique de Montréal) is an applied research and expertise centre in information technology, dedicated to making organizations more effective and competitive through the development of innovative technology and the transfer of leading edge know-how, while contributing to scientific advancement.
Cumulative degree days above 0°C can be used to determine when climate conditions are warm enough to support the growth of certain plants and pests. When the daily average temperature is warmer than 0°C, degree days are accumulated. More info can be found in the variable section of ClimateData.ca.
Degree Days form the basis for a number of climate indices which are used in agriculture, energy, transport and human health. The threshold temperature is core to the degree day index and, as with other climate indices, some specific temperature threshold values are associated with particular degree day indices, e.g., growing degree days, heating degree days and cooling degree days.
The degree day index generally provides information about heat energy that is available (e.g., in agriculture), or is required (e.g., for space heating in buildings), although there are other applications. Degree days can be calculated above, or below, the threshold temperature.
Degree days (DD) above particular threshold temperatures provide information about heat energy available. They are often used in agriculture to determine if there is sufficient heat energy at a particular location to allow crops or pest species to mature, or to reach certain points in their lifecycles. Growing Degree Days and Cooling Degree Days are in this category. The larger the degree day total, the more energy available in the time period considered.
Degree days (DD) below particular threshold temperatures provide information about heat energy required. They are often used in space heating of buildings. Heating Degree Days are in this category. The larger the degree day total, the more energy is required.
Since most Global Climate Model data are provided on large spatial grids, typically of the order of several hundred kilometres, a technique called ‘downscaling’ is used to transform these data to a finer resolution (tens of kilometres) which is more locally relevant. There are two main types of downscaling: statistical downscaling and dynamical downscaling.
Dynamical downscaling of Global Climate Models (GCMs) involves the use of high resolution regional climate models (RCMs) in the generation of climate projections over a limited region. These models include more detailed topographic information and some are able to directly represent atmospheric processes which occur at finer spatial scales. RCMs are very computationally intensive and it is only feasible to run them over limited regions (i.e., they are not run for the globe as a whole), limited time periods and for a reduced number of emissions scenarios. GCMs provide the boundary information required to drive an RCM, so although they are run over limited regions, their climate is consistent with global conditions.
Winds which blow from east to west. Also known as easterlies.
El Niño is an extreme phase of the ENSO (El Niño Southern Oscillation) cycle which involves a warming of the ocean surface in the central and eastern tropical Pacific Ocean. Low level surface winds which normally blow east to west along the equator are weakened or in some cases blow in the other direction. When this happens, instead of warm water being transported from South America towards Asia, it is instead pushed east, towards the west coast of the Americas. This warmer water causes the Pacific jet stream to move south, resulting in the northern US and Canada being drier and warmer than usual.
A plausible representation of the future development of emission of substances that are potentially radiatively active in the atmosphere, such as greenhouse gases and aerosols. They are based on assumptions regarding driving forces like demographic and socioeconomic development, or technological change.
Term used to refer to the complete set of climate simulations or climate scenarios used for a given study. Because no one model can be considered best, it is standard practice in climate change studies to use the outputs of many models when studying the projected changes. Consequently, ensemble is usually a synonym for the term multimodel ensemble. Note, however, that other, more restrictive, definitions exist for ensembles designed to study very specific scientific questions (for example, an ensemble could represent a set of simulations made with the same climate model, using the same emissions scenario, but initialized using different starting conditions). More info can be found in the Learning Zone.
The El Niño-Southern Oscillation is a climate pattern of shifting sea surface temperature in the tropical Pacific ocean, which impacts both North American and global weather patterns. On periods between 3-7 years the temperature of the sea surface changes from 1 to 3 degrees above or below normal. This temperature change directly impacts rainfall in the tropics, having knock on affects for the rest of the world. The extreme phases of the ENSO cycle are El Niño (warmer) and La Niña (colder), with the third phase, ENSO-neutral representing the between phase. See El Niño, La Niña and ENSO-neutral for more information.
ENSO-neutral is a phase of the ENSO cycle which is neither of the two extremes (El Niño or La Niña). In this case tropical sea surface temperatures are close to average, and winds blow east to west.
The combined process through which water is transferred to the atmosphere from open water and ice surfaces, bare soil and vegetation.
External climate forcings are climate forcing which impact the climate system while not being a part of the system itself. They can be natural (such as volcanic activity) or anthropogenic (such as greenhouse gas emissions).
Extreme climate or weather events are unusually severe conditions which deviate from the regular climate of a region. Examples of these are prolonged heatwaves and flooding.
The First Fall Frost marks the approximate end of the growing season for frost-sensitive crops and plants. When the lowest temperature of the day is colder than 0°C for one consecutive day (after July 15th) the date of the first fall frost is established. More info can be found on the variable section of ClimateData.ca.
This is a count of the days when the air temperature fluctuates between freezing and non-freezing temperatures on the same day. The temperature thresholds defining the cycle may be slightly different depending on the application. More info can be found on the variable section of ClimateData.ca
Frost Days describe the number of days where the coldest temperature of the day is lower than 0°C. More info can be found on the variable section of ClimateData.ca
The Frost Free Season is the approximate length of the growing season during which there are no freezing temperatures to kill or damage frost-sensitive plants. This index describes the number of days between the Last Spring Frost and the First Fall Frost. More info can be found on the variable section of ClimateData.ca
The GeoMet platform provides public access to the Meteorological Service of Canada (MSC) and Environment and Climate Change Canada (ECCC) data via interoperable web services and application programming interfaces (API). The daily climate station observations and MSC Climate Normals data on ClimateData.ca are provided by this service.
Climate related events and effects which have negative impacts on the health of humans and the environment. Examples include extreme heat waves, droughts, wildfires, floods, ice storms.
Heating degree days (HDDs) give an indication of the amount of space heating (e.g., from a gas boiler/furnace, baseboard electric heating or fireplace) that may be required to maintain comfortable conditions inside a building during cooler months. More info can be found on the variable section of ClimateData.ca
Hottest Day describes the warmest daytime temperature in the selected time period. In general, the hottest day of the year occurs during the summer months. More info can be found in the variable section of ClimateData.ca
The Humidex was developed by the Meteorological Service of Canada to describe how hot and humid the weather feels to the average person. In Canada, it is recommended that outdoor activities be moderated when the humidex exceeds 30, and that all unnecessary activities cease when it passes 40. More info can be found in the variable section of ClimateData.ca.
Ice Days describe the number of days where the warmest temperature of the day is not above 0°C. More info can be found in the variable section of ClimateData.ca
Term used to refer to properties of the climate that are not measured in the field or calculated by climate models but rather that are calculated or derived from climate variables such as temperature and precipitation. They are categorized into groups such as precipitation, temperature, and degree days indices . Examples include the number of growing degree-days, freeze-thaw cycles, and the drought code index (see variable). Indices are used to provide more meaningful descriptors of climate.
Initial conditions are starting conditions for a model simulation. For climate projections, the initial conditions are typically based on simulated climate conditions during the pre-industrial period. For seasonal to decadal forecasts, the initial conditions typically come from estimates based on recent observations of the state of the atmosphere and other climate system components.
Intergovernmental Panel on Climate Change
The IPCC is an international body administered by the United Nations. It was created to assess climate science research, and it regularly issues authoritative assessment reports about the science of climate change, climate change impacts, and policy options for adaptation and mitigation.
The instantaneous rate of energy received from the sun, by a surface, measured in W/m2.
Jet streams are relatively narrow bands of strong wind in the upper levels of the atmosphere.
La Niña is an extreme phase of the ENSO (El Niño-Southern Oscillation) cycle which involves a cooling of the ocean surface in the central and eastern tropical Pacific Ocean. Low level surface winds which blow east to west are intensified. This results in more warm water being pushed from South America towards Asia, as well as the northward movement of the Pacific jet stream, bringing heavy rains and flooding to the Pacific Northwest and Canada, and drought in the southern US. Winter temperatures are cooler than normal in the North and warmer than normal in the South.
Lapse rate refers to the rate at which temperature changes with height in the atmosphere. In general, temperature typically decreases with height, often by about 7°C per 1000m.
The Last Spring Frost marks the approximate beginning of the growing season for frost-sensitive crops and plants. When the lowest temperature of the day remains above 0°C for one consecutive day (before July 15th) the date of the last spring frost is established. More info can be found on the variable section of ClimateData.ca
Maximum 1-Day Total Precipitation describes the largest amount of precipitation (rain and snow combined) that falls within a single 24-hour day for the selected time period. This index is commonly referred to as the wettest day of the year. More info can be found in the variable section of ClimateData.ca
Maximum 5-Day Precipitation describes the largest amount of precipitation (rain and snow combined) to fall over 5 consecutive days. More info can be found on the variable section of ClimateData.ca
The maximum number of consecutive dry days variables describes the longest spell of days where less than 1mm of precipitation falls daily. More info can be found on the variable section of ClimateData.ca
Maximum temperature describes the warmest temperature of the 24-hour day. Typically, but not always, the maximum temperatures occur during the day and so this variable is commonly referred to as the daytime high.
MBCn (N-Dimensional Multivariate Bias Correction) is a statistical method for downscaling daily climate model projections. It is a multivariate method and therefore is used to downscale multiple variables at once and preserve the relationships between variables. The CanDCS-m6, Humidex and SPEI datasets were produced using this method. Learn more about MBCn on the About Page.
Mean temperature describes the average temperature for the 24-hour day. More info can be found on the variable section of ClimateData.ca.
Minimum temperature describes the coldest temperature of the 24-hour day. Typically, but not always, the minimum temperature occurs at night and so this variable is commonly referred to as the nighttime low. More info can be found on the variable section of ClimateData.ca
A human intervention to reduce emissions or enhance the sinks of greenhouse gases.
Climate model output which is for the period in which the model simulation does not have any future emissions forcing it. The end of the modelled historical period is not necessarily the present but is often a pre-established year (such as 2015). They are used to validate climate models against observations.
North Atlantic Oscillation (NAO) index is a climate pattern which is defined by differences in surface sea-level pressure (SLP) between the subtropical high ( a region of high SLP around the Azores) and subpolar low (a region of low SLP around Iceland). It controls the strength and direction of westerly winds and the location of storm tracks in the North Atlantic. The positive phase (when the difference in SLP between the subtropical high and subpolar low is high) is assoicated with above normal temperatures in the Eastern United states and cooler temperatures in the eastern Canadian Arctic and eastern Canada, with opposite signals seen in the negative cycle. The NAO has considerable interannual and interseasonal variability with prolonged (several months) of both positive and negative phases being common, and generally impacts weather in Europe more than in North America.
NRCANmet is gridded historical observational dataset which is produced by NRCan (Natural Resources Canada) and is available at roughly ~10km grids over Canada. The gridding was produced using the (ANUSPLIN)[link] method. NRCANmet was used to downscale and bias-adjust CanDCS-u6. See the (NRCanMet About page)[link] for more details.
The Number of Periods with more than 5 Consecutive Dry Days describes the number of times when daily precipitation totals are less than 1mm a day for six or more days straight.
The forecasting of weather elements through the use of numerical models. They process current weather observations in order to forecast future weather.
The observed historical climatology is created using observations such as temperature or precipitation data from meteorological stations. It describes historical conditions observed during the historical reference period, which typically spans 30 years. The observed historical climatology is frequently used to provide context for forecasts or projections.
The observed historical climatology is created using observations such as temperature or precipitation data from meteorological stations. It describes historical conditions observed during the historical reference period, which typically spans 30 years. The observed historical climatology is frequently used to provide context for forecasts or projections.
A regional climate services hub for Quebec, based in Montreal, QC, providing regionally relevant climate information for effective planning and policy making. More info can be found on the Ouranos website.
PCIC is a regional climate services hub for British Columbia and the Yukon, based in Victoria, BC, providing regionally relevant climate information for effective planning and policy making. More info can be found on the PCIC website.
A fast, narrow current of air which flows westerly, encircling the globe. It is the mechanism for connecting ENSO (El Niño-Southern Oscillation) to North American winter climate patterns.
A gridded observational dataset which consists of a blend of three daily precipitation and temperature observation-based datasets across Canada, where the gridded observations in each dataset were generated by interpolating quality-controlled weather station observations. The 3 datasets used are NRCANmet-Adjusted Precipitation which spans Canada, NRCANmetV2 Temperature which spans North America, and PNWNAmet which covers Western Canada and the Pacific Northwest.
A statistical term which describes how a value compares to other values from the same dataset. It indicates the percentage of values in the dataset which are equal to or below a given value. For example, if a precipitation event is of the 90th percentile, that means that 90% of precipitation events are equal to or below that precipitation amount. Percentiles are often used in climate science when discussing extreme events.
Performance metrics evaluate how well a seasonal prediction system or climate model predicts observed climate conditions. Different performance metrics are used to evaluate different aspects of the system and model performance.
Physical risks are risks related to physical impacts of climate change and can be event driven (e.g., a flood) or associated with longer-term shifts in climate patterns. Examples of these include thawing permafrost, sea level rise, droughts and floods. These endanger humans, the environment and subsequently the economy. See the Glossary definition of hazard.
A gridded observational dataset which is one of the three datasets comprising PCIC-Blend, produced by PCIC (Pacific Climate Impacts Consortium). PNWNAmet covers Western Canada and the Pacific Northwest. More information can be found on the PCIC website.
An area of low pressure and cold air surrounding the poles, which weakens in the summer and strengthens in the winter. Sometimes in the winter the it expands, sending cold air down into Canada and the US.
Prairie Climate Centre. The PCC is a climate change research, communication, and policy centre based at the University of Winnipeg.
Any and all forms of water, liquid or solid, that falls from clouds and reaches the ground. The measurement of precipitation is expressed in terms of vertical depth of water (or water equivalent in the case of solid forms) which reaches the ground during a stated period. The millimetre (mm) is the unit of measurement of liquid precipitation and the vertical depth of water or water equivalent is expressed to the nearest 0.2 mm. Less than 0.2 mm is called a “Trace”. For climate stations operating on a 24 hours basis, total precipitation measurements end at 06:01 UTC (01:01 EST) of the following day (see the definition of climatological day).
The number of precipitation events during a given time period. Usually a precipitation event is defined as liquid precipitation above 1mm/day, but this can differ between places.
A probabilistic forecast gives information about the probability or likelihood of different outcomes occurring. For example, a probabilistic seasonal forecast may provide the probability of the mean temperature over the season being above normal, near normal, or below normal. Seasonal to decadal forecasts are often provided as probabilistic forecasts since they usually have larger uncertainties than weather forecasts. Providing the probabilities of different outcomes allows decision-makers to use their own judgment and risk tolerance when considering these forecasts during planning.
A bias adjustment method in climate modelling. This is achieved by aligning the quantile distributions of the observations with model projections.
A radar product which combines information from multiple radars to give a regional or national view of reflectivity or precipitation. For Canada the weather radar mosaic used combines all radars from Canada and America, to a maximum of 180 radars.
Raw station data, also known as observations, or weather station data are the weather measurements from weather stations which have not been adjusted in any way to take into account changes in station location or instrumentation.
Datasets of weather and climate variables for the recent past (usually 1950 onwards) to present. They combine weather and satellite measurements using climate and weather models to produce complete records for weather variables for the entire globe or specific regions (for regional reanalysis). Instead of using interpolation they use physics to combine measurements and infer variables which are not measured. They are incredibly useful for climate and weather analysis for the globe, especially for regions with limited observational networks, such as the Canadian Arctic.
In practice, it often refers to a period of time from the recent past used in the production of climate scenarios. Future period values produced by climate models are compared with those from this period to evaluate changes. The WMO recommends 30-year intervals as reference periods, such as 1971-2000 or 1981-2010; however there are exceptions. A synonymous term is baseline period.
Similar to GCMs, the regional climate model is a mathematical representation of the climate system, based on equations describing the physical processes governing the climate. RCMs have a finer resolution than GCMs and therefore contain a better representation of topography and can include processes and features, such as lakes, which are too small to resolve in GCMs. As a consequence they are more expensive to run and typically operate as ‘limited domain’ models, meaning that they cover only a portion of the globe.
Change of ocean level relative to land, which is a combination of effects from global sea-level change and the vertical motion of land. More info can be found on the variable section of ClimateData.ca.
The date a forecast is available for release on ClimateData.ca. For seasonal forecasts that are updated monthly, the release date is usually the first day of the current month, one day after the forecast was produced. For decadal forecasts that are updated annually, the release date is typically early in the calendar year.
RCPs are emissions scenarios and are used in climate science to describe potential futures based on a range of greenhouse gas and aerosol emissions. Each RCP consists of a time series of emissions and concentrations of greenhouse gases and aerosols. Each RCP is identified by a number (e.g., RCP4.5) indicating the increase in end-of-century radiative forcing compared to pre-industrial conditions. Representative is used to signify that the RCP represents only one of many possible scenarios that would lead to the specific radiative forcing characterizing the scenario. Four main RCPs were developed for use with the CMIP5 generation of climate models, with results detailed in the IPCC’s Fifth Assessment Report. Three main RCPs are provided on ClimateData.ca; low (RCP2.6), moderate (RCP4.5) and high (RCP8.5). More detail on each can be found in the Learning Zone.
In climate models, the term resolution is most often used to mean spatial resolution and refers to the physical distance between each point on the model grid at which the physical equations describing climate process are solved, such as every 100km. Temporal resolution refers to the model time step, i.e., the time elapsed between each calculation, such as hourly, or daily.
A seasonal forecast tells us how the overall climate conditions for a future season are likely to compare to past conditions. Seasonal forecasts on ClimateData.ca are probabilistic forecasts, updated monthly, and available for rolling 3-month periods that fall within the next 12 months. These forecasts are based on an ensemble of climate model simulations that start from initial conditions based on observations of the recent climate and are run forward in time to predict how conditions may evolve over future seasons. Seasonal forecasts do not take into account different emissions scenarios, as the differences between scenarios are negligible at seasonal to annual scales.
A seasonal prediction system uses one or more models to create seasonal forecasts. The model simulations start from initial conditions based on observations of the recent climate and are run forward in time to predict how conditions may evolve over the upcoming months and seasons. These systems typically include additional post-processing steps to improve the forecasts by adjusting the model data based on past performance. The Canadian Seasonal to Interannual Prediction System version 3 (CanSIPSv3) is one example of a seasonal prediction system.
Annual average precipitation rate for days with daily precipitation over 1 mm, i.e. the average amount of precipitation that falls on wet days in a year.
Climate simulations represent the outcome of running a climate model for a certain period of time. The time span of a simulation can range from a few years to thousands of years and will iteratively be computed at intervals of a few minutes. They are run for both the past and the future. There are historic and future components to the simulation. The historical period can be used to compare the accuracy of the model to past observations, while the future period is used to explore how future climate responds to a particular emissions scenario. For the CMIP6 generation of climate models, the historical period spans 1850-2014 with the future simulations starting in 2015 and continuing until 2100 (and beyond in some cases).
Any process, activity or mechanism which removes a greenhouse gas, in particular CO2, or precursors of GHGs, from the atmosphere.
A category of performance metrics that measures how accurately a prediction system or model performs, calculated by comparing forecasts for a historical period against observed climate conditions over that period. Skill gives a relative measure of how much trust to place in a forecast, based on how well past forecasts were able to predict what was ultimately observed.
A drought index based on the simple water balance equation P-PET, i.e., precipitation minus potential evapotranspiration. By including PET, SPEI captures the impact of increased temperatures on water demand. SPEI results should be interpreted as a relative measure of surface water surplus or deficit with respect to hydroclimate conditions of a reference period. For more information, please consult the About Page.
Statistical downscaling uses statistical methods to transform large-scale climate information to more locally-relevant spatial scales. In general, this type of downscaling develops statistical relationships between observed local and large-scale climates which can then be applied to GCM ouput to transform coarse-scale climate projections to the spatial scales more appropriate for use as input to regional or local climate impact studies . The observed data set used in this type of downscaling is often referred to as the “target” data set. Two statistical downscaling methods which are commonly used in Canada are BCCAQv2 and MBCn. For more information about these methods, see the glossary entries and visit the About Page on ClimateData.ca.
A target dataset refers to observations, reanalysis data sets or even climate model outputs, which are used as a reference or baseline in the (downscaling)[link] process. These datasets typically represent the climate conditions, such as temperature and precipitation, that the downscaling models aim to replicate in the process of transforming climate data from coarse to finer spatial resolutions. For CanDCS-U5 and CanDCS-U6, NRCANmet is the target dataset; for Humidex it is ERA-5 Land, and for CanDCS-M6 it is PCIC-Blend.
Total precipitation amount (rain and snow) for a given time period.
Transition risks are risks related to the transition to a lower carbon economy. They are associated with the pace and extent at which organizations adapt to the pace of change to reduce greenhouse gas emissions and transition to renewable energy.
Tropical Nights (Days with Tmin > x°C) describes the number of days where the nighttime low temperature is warmer than x°C (Thresholds of 18, 20 and 22°C are provided on ClimateData.ca while users can enter custom thresholds on the (Download page)[link to Download page]). More info can be found on the variable section of ClimateData.ca
Uncertainty in seasonal to decadal forecasting and climate modelling describes the inability of models to make perfectly accurate predictions of the future climate. Uncertainty arises from differences in emissions scenarios, model limitations, natural climate variability, limitations in observational data, and other factors. Considering a range of possible futures rather than a single possible future can help to quantify the uncertainty.
Winds which blow from west to east. Also known as westerlies.
Wet Days >=xmm describes the number of days where at least x mm of precipitation (rain and snow combined) falls in the selected time period, (at ClimateData.ca we explore this definition under thresholds of 10 and 20 mm/day). More info can be found in the variable section of ClimateData.ca.
A specalized agency of the United Nations which is responsible for promoting international cooperation on atmospheric science, climatology, hydrology and geophysics.
This project was undertaken with the support of:
