Data
Our principal products are downscaled historical and projected monthly climate data, primarily temperature and precipitation across Alaska and large regions of Western Canada. Projected data are produced for three scenarios (B1, A1B, A2). Additionally, SNAP produces derived data from the above base datasets through various modeling efforts. Derived data products include potential evapotranspiration, vegetation, fire, permafrost, day of freeze, day of thaw, and the subsequent length of growing season, as well as decadal, seasonal, and annual averages.
Please visit our Methods section for a description of our downscaling procedure.
To visualize a selection of datasets, please visit the map tool.
For a full list of our available data, please see below.
All of our downloadable data is provided in GeoTIFF format, georeferenced to the North American Datum of 1983 and projected in Alaska Albers Equal Area Conic in units of meters (NAD83 Alaska Albers). Geotiffs can be read by many open source and commercial GIS and data manipulation programs including ArcGIS, QGIS, R (raster package recommended), GDAL, GRASS, and many others.
Our data is currently served through zip files. Once uncompressed, each file represents one time step (month, decade, season, etc) across the full spatial extent for that product. Currently, spatial extents are Alaska-wide or Alaska-Western Canada (YT, BC, AB, SK, MB).
While it’s hard to have a completely static file naming scheme, we make every attempt to keep some consistency across our various datasets. This naming scheme outlined below is our general guide, although it does vary depending upon each dataset. Please refer to the full metadata for details on specific datasets.
[variable]_[metric]_[units]_[format]_[assessmentReport]_[group]_[model]_[scenario]_[timeFrame].[fileFormat]
| variable | key |
|---|---|
| tas | temperature |
| pr | precipitation |
| dot | day of thaw |
| dof | day of freeze |
| logs | length of growing season |
| pet | potential evapotranspiration |
| fs | snow-day fraction |
All information produced by the Scenarios Network for Alaska and Arctic Planning is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Attribution text provided on our FAQ page. If you are interested in commercialization opportunities and/or collaborative R&D activities please contact us.
Projected Data
Projected Monthly Temperature and Precipitation - 771m CMIP3/AR4
Projected (2001-2100: B1, A1B, and A2 scenarios) monthly average temperature and total precipitation from 5 AR4 GCMs that perform best across Alaska and the Arctic, downscaled to 771m via the delta method. A 5-Model Average is also included.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Monthly |
| Spatial Extent | Alaska |
Temperature
Metadata: Projected Monthly Average Temperature 771m AR4
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2099 (2.5 GB) |
| cccma_cgcm31 | 2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
| gfdl_cm2_1 | 2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
| miroc3_2_medres | 2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
| mpi_echam5 | 2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
| ukmo_hadcm3 | 2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2100 (2.6 GB) |
2001–2049 (2.5 GB) 2050–2099 (2.6 GB) |
Precipitation
Metadata: Projected Monthly Total Precipitation 771m AR4
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2049 (2.1 GB) 2050–2100 (2.2 GB) |
2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
2001–2049 (2.1 GB) 2050–2099 (2.2 GB) |
| cccma_cgcm31 | 2001–2049 (2.1 GB) 2050–2100 (2.2 GB) |
2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
| gfdl_cm2_1 | 2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
| miroc3_2_medres | 2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
| mpi_echam5 | 2001–2049 (2.1 GB) 2050–2100 (2.2 GB) |
2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
| ukmo_hadcm3 | 2001–2049 (2.1 GB) 2050–2100 (2.2 GB) |
2001–2049 (2.1 GB) 2050–2100 (2.3 GB) |
2001–2049 (2.1 GB) 2050–2099 (2.3 GB) |
Projected Derived Temperature Products - 771m CMIP3/AR4
Projected (2010–2100: B1, A1B, and A2 scenarios) derived temperature products from 5 AR4 GCMs that perform best across Alaska and the Arctic, downscaled to 771m via the delta method. A 5-Model Average is also included.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska |
Decadal Summaries by Month, Year, or Season
Metadata by product
- Projected Decadal Averages of Monthly Mean Temperatures 771m AR4
- Projected Decadal Averages of Annual Mean Temperatures 771m AR4
- Projected Decadal Averages of Seasonal Mean Temperatures 771m AR4
All products by model and scenario
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2100 (638 MB) | 2001–2100 (637 MB) | 2001–2100 (637 MB) |
| cccma_cgcm31 | 2001–2100 (639 MB) | 2001–2100 (639 MB) | 2001–2100 (638 MB) |
| gfdl_cm2_1 | 2001–2100 (637 MB) | 2001–2100 (637 MB) | 2001–2100 (637 MB) |
| miroc3_2_medres | 2001–2100 (641 MB) | 2001–2100 (640 MB) | 2001–2100 (640 MB) |
| mpi_echam5 | 2001–2100 (639 MB) | 2001–2100 (640 MB) | 2001–2100 (640 MB) |
| ukmo_hadcm3 | 2001–2100 (642 MB) | 2001–2100 (642 MB) | 2001–2100 (642 MB) |
Day of Freeze, Thaw, Length of Growing Season
Estimated Julian days of freeze and thaw (dof, dot) are calculated by assuming a linear change in temperature between consecutive months. Mean monthly temperatures are used to represent daily temperature on the 15th day of each month. When consecutive monthly midpoints have opposite sign temperatures, the day of transition (freeze or thaw) is the day between them on which temperature crosses zero degrees C. The length of growing season (logs) refers to the number of days between the days of freeze and thaw. More detailed explanations are discussed in the metadata.
Date of Freeze, Thaw
Metadata: Projected Day of Freeze or Thaw 771 AR4
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2100 (51 MB) | 2001–2100 (51 MB) | 2001–2100 (52 MB) |
| cccma_cgcm31 | 2001–2100 (52 MB) | 2001–2100 (52 MB) | 2001–2100 (52 MB) |
| gfdl_cm2_1 | 2001–2100 (52 MB) | 2001–2100 (51 MB) | 2001–2100 (52 MB) |
| miroc3_2_medres | 2001–2100 (51 MB) | 2001–2100 (51 MB) | 2001–2100 (51 MB) |
| mpi_echam5 | 2001–2100 (51 MB) | 2001–2100 (51 MB) | 2001–2100 (52 MB) |
| ukmo_hadcm3 | 2001–2100 (52 MB) | 2001–2100 (51 MB) | 2001–2100 (52 MB) |
Length of Growing Season
Metadata: Projected Length of Growing Season 771 AR4
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2100 (31 MB) | 2001–2100 (31 MB) | 2001–2100 (31 MB) |
| cccma_cgcm31 | 2001–2100 (31 MB) | 2001–2100 (31 MB) | 2001–2100 (32 MB) |
| gfdl_cm2_1 | 2001–2100 (31 MB) | 2001–2100 (31 MB) | 2001–2100 (31 MB) |
| miroc3_2_medres | 2001–2100 (31 MB) | 2001–2100 (30 MB) | 2001–2100 (31 MB) |
| mpi_echam5 | 2001–2100 (31 MB) | 2001–2100 (30 MB) | 2001–2100 (31 MB) |
| ukmo_hadcm3 | 2001–2100 (32 MB) | 2001–2100 (31 MB) | 2001–2100 (32 MB) |
Projected Derived Precipitation Products - 771m CMIP3/AR4
Projected (2010-2100: B1, A1B, and A2 scenarios) derived precipitation products from 5 AR4 GCMs that perform best across Alaska and the Arctic, downscaled to 771m via the delta method. A 5-Model Average is also included.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska |
Decadal Summaries by month, year, or season
Metadata by product
- Projected Decadal Averages of Monthly Total Precipitation 771m AR4
- Projected Decadal Averages of Annual Total Precipitation 771m AR4
- Projected Decadal Averages of Seasonal Total Precipitation 771m AR4
All products by model and scenario
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2100 (612 MB) | 2001–2100 (619 MB) | 2001–2100 (619 MB) |
| cccma_cgcm31 | 2001–2100 (612 MB) | 2001–2100 (618 MB) | 2001–2100 (621 MB) |
| gfdl_cm2_1 | 2001–2100 (618 MB) | 2001–2100 (626 MB) | 2001–2100 (623 MB) |
| miroc3_2_medres | 2001–2100 (613 MB) | 2001–2100 (618 MB) | 2001–2100 (618 MB) |
| mpi_echam5 | 2001–2100 (609 MB) | 2001–2100 (617 MB) | 2001–2100 (614 MB) |
| ukmo_hadcm3 | 2001–2100 (610 MB) | 2001–2100 (621 MB) | 2001–2100 (620 MB) |
Projected Monthly Temperature and Precipitation - 2 km CMIP3/AR4
Projected (2001–2100: B1, A1B, and A2 scenarios) monthly temperature and precipitation from 5 AR4 GCMs that perform best across Alaska and the Arctic, downscaled to 2 km via the delta method. A 5-Model Average is also included.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2 km |
| Temporal Resolution | Monthly |
| Spatial Extent | Alaska and Western Canada (YT, BC, AB, SK, MB) |
Temperature
Metadata: Projected Monthly Average Temperature 2 km AR4
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2100 (2.6 GB) | 2001–2100 (2.6 GB) | 2001–2100 (2.6 GB) |
| cccma_cgcm31 | 2001–2100 (2.6 GB) | 2001–2100 (2.6 GB) | 2001–2100 (2.6 GB) |
| gfdl_cm2_1 | 2001–2100 (2.6 GB) | 2001–2100 (2.6 GB) | 2001–2100 (2.6 GB) |
| miroc3_2_medres | 2001–2100 (2.6 GB) | 2001–2100 (2.6 GB) | 2001–2100 (2.6 GB) |
| mpi_echam5 | 2001–2100 (2.6 GB) | 2001–2100 (2.6 GB) | 2001–2100 (2.6 GB) |
| ukmo_hadcm3 | 2001–2100 (2.7 GB) | 2001–2100 (2.6 GB) | 2001–2100 (2.7 GB) |
Precipitation
Metadata: Projected Monthly Total Precipitation 2 km AR4
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2100 (2.3 GB) | 2001–2100 (2.3 GB) | 2001–2100 (2.3 GB) |
| cccma_cgcm31 | 2001–2100 (2.4 GB) | 2001–2100 (2.3 GB) | 2001–2100 (2.3 GB) |
| gfdl_cm2_1 | 2001–2100 (2.3 GB) | 2001–2100 (2.3 GB) | 2001–2100 (2.4 GB) |
| miroc3_2_medres | 2001–2100 (2.3 GB) | 2001–2100 (2.3 GB) | 2001–2100 (2.3 GB) |
| mpi_echam5 | 2001–2100 (2.4 GB) | 2001–2100 (2.4 GB) | 2001–2100 (2.4 GB) |
| ukmo_hadcm3 | 2001–2100 (2.3 GB) | 2001–2100 (2.3 GB) | 2001–2100 (2.3 GB) |
Projected Derived Temperature Products - 2 km CMIP3/AR4
Projected (2010–2100: B1, A1B, and A2 scenarios) derived temperature products from 5 AR4 GCMs that perform best across Alaska and the Arctic, downscaled to 771m via the delta method. A 5-Model Average is also included.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2 km |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska and Western Canada (YT, BC, AB, SK, MB) |
Decadal Summaries by month, year, or season
Metadata by product
- Projected Decadal Averages of Monthly Mean Temperatures 2km AR4
- Projected Decadal Averages of Annual Mean Temperatures 2km AR4
- Projected Decadal Averages of Seasonal Mean Temperatures 2km AR4
All products by model and scenario
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2100 (375 MB) | 2001–2100 (375 MB) | 2001–2100 (376 MB) |
| cccma_cgcm31 | 2001–2100 (333 MB) | 2001–2100 (333 MB) | 2001–2100 (333 MB) |
| gfdl_cm2_1 | 2001–2100 (332 MB) | 2001–2100 (332 MB) | 2001–2100 (332 MB) |
| miroc3_2_medres | 2001–2100 (332 MB) | 2001–2100 (334 MB) | 2001–2100 (336 MB) |
| mpi_echam5 | 2001–2100 (332 MB) | 2001–2100 (333 MB) | 2001–2100 (332 MB) |
| ukmo_hadcm3 | 2001–2100 (334 MB) | 2001–2100 (336 MB) | 2001–2100 (336 MB) |
Day of Freeze, Thaw, Length of Growing Season
Estimated Julian days of freeze and thaw (dof, dot) are calculated by assuming a linear change in temperature between consecutive months. Mean monthly temperatures are used to represent daily temperature on the 15th day of each month. When consecutive monthly midpoints have opposite sign temperatures, the day of transition (freeze or thaw) is the day between them on which temperature crosses zero degrees C. The length of growing season (logs) refers to the number of days between the days of freeze and thaw. More detailed explanations are discussed in the metadata.
Day of Freeze, Thaw
Metadata: Projected Day of Freeze or Thaw 2km AR4
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2100 (27 MB) | 2001–2100 (27 MB) | 2001–2100 (27 MB) |
| cccma_cgcm31 | 2001–2100 (27 MB) | 2001–2100 (27 MB) | 2001–2100 (27 MB) |
| gfdl_cm2_1 | 2001–2100 (27 MB) | 2001–2100 (27 MB) | 2001–2100 (27 MB) |
| miroc3_2_medres | 2001–2100 (27 MB) | 2001–2100 (27 MB) | 2001–2100 (27 MB) |
| mpi_echam5 | 2001–2100 (27 MB) | 2001–2100 (27 MB) | 2001–2100 (27 MB) |
| ukmo_hadcm3 | 2001–2100 (27 MB) | 2001–2100 (27 MB) | 2001–2100 (27 MB) |
Length of Growing Season
Metadata: Projected Length of Growing Season 2km AR4
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2100 (17 MB) | 2001–2100 (17 MB) | 2001–2100 (17 MB) |
| cccma_cgcm31 | 2001–2100 (17 MB) | 2001–2100 (17 MB) | 2001–2100 (17 MB) |
| gfdl_cm2_1 | 2001–2100 (17 MB) | 2001–2100 (17 MB) | 2001–2100 (17 MB) |
| miroc3_2_medres | 2001–2100 (17 MB) | 2001–2100 (17 MB) | 2001–2100 (17 MB) |
| mpi_echam5 | 2001–2100 (17 MB) | 2001–2100 (17 MB) | 2001–2100 (17 MB) |
| ukmo_hadcm3 | 2001–2100 (17 MB) | 2001–2100 (17 MB) | 2001–2100 (17 MB) |
Projected Derived Precipitation Products - 2 km CMIP3/AR4
Projected (2010-2100: B1, A1B, and A2 scenarios) derived precipitation products from 5 AR4 GCMs that perform best across Alaska and the Arctic, downscaled to 771m via the delta method. A 5-Model Average is also included.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska and Western Canada (YT, BC, AB, SK, MB) |
Decadal Summaries by month, year, and season
Metadata by product
- Projected Decadal Averages of Monthly Total Precipitation 2km AR4
- Projected Decadal Averages of Annual Total Precipitation 2km AR4
- Projected Decadal Averages of Seasonal Total Precipitation 2km AR4
All products by model and scenario
| Scenario | |||
|---|---|---|---|
| Model | B1 | A1B | A2 |
| 5–model Average | 2001–2100 (351 MB) | 2001–2100 (353 MB) | 2001–2100 (353 MB) |
| cccma_cgcm31 | 2001–2100 (318 MB) | 2001–2100 (320 MB) | 2001–2100 (321 MB) |
| gfdl_cm2_1 | 2001–2100 (319 MB) | 2001–2100 (321 MB) | 2001–2100 (320 MB) |
| miroc3_2_medres | 2001–2100 (317 MB) | 2001–2100 (319 MB) | 2001–2100 (319 MB) |
| mpi_echam5 | 2001–2100 (318 MB) | 2001–2100 (320 MB) | 2001–2100 (320 MB) |
| ukmo_hadcm3 | 2001–2100 (318 MB) | 2001–2100 (320 MB) | 2001–2100 (320 MB) |
Projected Monthly Potential Evapotranspiration - 2km CMIP3/AR4
Projected (2001-2099: A1B scenario) monthly total potential evapotranspiration from 5 AR4 GCMs that perform best across Alaska and the Arctic, utilizing 2km downscaled temperature as model inputs.
These potential evapotranspiration (PET) estimates were produced using the Hamon equation, which calculates PET as a function of temperature and day length. Potential evapotranspiration may also be influenced by cloud cover, humidity, and wind speed. The Hamon equation can not explicitly account for variability in these aspects of weather and climate, so it may over or underestimate changes in PET if humidity, cloud cover, or wind speeds change substantially. In addition, the Hamon equation was developed to calculate daily potential evapotranspiration, and so these estimates, based on monthly data, may differ from those calculated from daily data. We can also provide PET estimated by the Priestley-Taylor equation and standard equations for estimating the surface radiation budget from temperature. Priestley-Taylor data come with a much longer list of assumptions, including those that apply to the Hamon equation. Scripts used to produce both the Harmon and Priestley-Taylor versions are available online.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2km |
| Temporal Resolution | Monthly |
| Spatial Extent | Alaska |
Metadata by product
Metadata: Projected Monthly Total Potential Evapotranspiration 2km AR4
Equations used to derive data: Hamon PET equations (PDF, 597KB)
Data
| Scenario | |||
|---|---|---|---|
| Model | A1B | ||
| cccma_cgcm31 | 2001–2099 (757 MB) | ||
| gfdl_cm2_1 | 2001–2099 (759MB) | ||
| miroc3_2_medres | 2001–2099 (770MB) | ||
| mpi_echam5 | 2001–2099 (769MB) | ||
| ukmo_hadcm3 | 2001–2099 (762MB) | ||
Projected Derived Potential Evapotranspiration - 2km CMIP3/AR4
Projected (2001-2099: A1B scenario) monthly total potential evapotranspiration from 5 AR4 GCMs that perform best across Alaska and the Arctic, utilizing 2km downscaled temperature as model inputs.
These potential evapotranspiration (PET) estimates were produced using the Hamon equation, which calculates PET as a function of temperature and day length. Potential evapotranspiration may also be influenced by cloud cover, humidity, and wind speed. The Hamon equation can not explicitly account for variability in these aspects of weather and climate, so it may over or underestimate changes in PET if humidity, cloud cover, or wind speeds change substantially. In addition, the Hamon equation was developed to calculate daily potential evapotranspiration, and so these estimates, based on monthly data, may differ from those calculated from daily data. We can also provide PET estimated by the Priestley-Taylor equation and standard equations for estimating the surface radiation budget from temperature. Priestley-Taylor data come with a much longer list of assumptions, including those that apply to the Hamon equation. Scripts used to produce both the Harmon and Priestley-Taylor versions are available online.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2km |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska |
Decadal Summaries by Month, Year, or Season
Metadata by product
- Projected Decadal Averages of Monthly Total Potential Evapotranspiration 2km AR4
- Projected Decadal Averages of Annual Total Potential Evapotranspiration 2km AR4
- Projected Decadal Averages of Seasonal Total Potential Evapotranspiration 2km AR4
Equations used to derive data: Hamon PET equations (PDF, 597KB)
Data
| Scenario | |||
|---|---|---|---|
| Model | A1B | ||
| cccma_cgcm31 | 2001–2099 (188MB) | ||
| gfdl_cm2_1 | 2001–2099 (187MB) | ||
| miroc3_2_medres | 2001–2099 (188MB) | ||
| mpi_echam5 | 2001–2099 (189MB) | ||
| ukmo_hadcm3 | 2001–2099 (189MB) | ||
Projected Decadal Averages Of Monthly Snow-day Fraction 771m CMIP3/AR4
These snow-day fraction estimates were produced by applying equations relating decadal average monthly temperature to snow-day fraction to downscaled decadal average monthly temperature. Separate equations were used to model the relationship between decadal monthly average temperature and the fraction of wet days with snow for seven geographic regions in the state: Arctic, western Alaska, Interior, Cook Inlet, SW Islands, SW Interior, and the Gulf of Alaska coast.
Although the equations developed here provide a reasonable fit to the data, model evaluation demonstrated that some stations are consistently less well described by regional models than others. It is unclear why this occurs, but it is like related to localized climate conditions. Very few weather stations with long records are located above 500m elevation in Alaska, so the equations used here were developed primarily from low-elevation weather stations. It is not clear whether the equations will be completely appropriate in the mountains. Finally, these equations summarize a long-term monthly relationship between temperature and precipitation type that is the result of short-term weather variability. In using these equations to make projections of future snow, as assume that these relationships remain stable over time, and we do not know how accurate that assumption is.
Read the user’s guide for this data set (PDF, 1.5MB) for information on methodology and validation.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Monthly |
| Spatial Extent | Alaska |
Metadata by product
Metadata: Projected Decadal Averages Of Monthly Snow-day Fraction 771m AR4
Data
| Model | Data |
|---|---|
| cccma_cgcm31 | 2010–2099 (479 MB) |
| gfdl_cm2_1 | 2010–2099 (491MB) |
| miroc3_2_medres | 2010–2099 (461MB) |
| mpi_echam5 | 2010–2099 (476MB) |
| ukmo_hadcm3 | 2010–2099 (470MB) |
Historical Data
Historical Monthly Temperature and Precipitation - 771m CRU TS 3.0
Historical (1901–2006) monthly average temperature and total precipitation from CRU TS 3.0 climate data, downscaled to 771m via the delta method.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Monthly |
| Spatial Extent | Alaska |
Downloads
| Metadata | Data |
|---|---|
| Historical Monthly Average Temperature 771m CRUTS3.0/3.1 | 1901–1949 (2.5 GB) 1950–2006 (2.9 GB) |
| Historical Monthly Total Precipitation 771m CRUTS3.0/3.1.01 | 1901–1949 (2.1 GB) 1950–2006 (2.4 GB) |
Historical Monthly Temperature and Precipitation - 771m CRU TS 3.1/3.1.01
Historical (1901–2009) monthly average temperature and total precipitation from CRU TS 3.1.01 climate data, downscaled to 771m via the delta method.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Monthly |
| Spatial Extent | Alaska |
Downloads
| Metadata | Data |
|---|---|
| Historical Monthly Average Temperature 771m CRUTS3.1 | 1901–1949 (2.5 GB) 1950–2009 (3.0 GB) |
| Historical Monthly Total Precipitation 771m CRUTS3.1.01 | 1901–1949 (2.1 GB) 1950–2009 (2.5 GB) |
Historical Derived Temperature Products - 771m CRU TS 3.0
Historical (1910–1999) derived temperature products from CRU TS 3.0 climate data, downscaled to 771m via the delta method.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska |
Decadal summaries by month, year, and season
Metadata by product
- Historical Decadal Averages of Monthly Mean Temperatures 771m CRUTS3.0
- Historical Decadal Averages of Annual Mean Temperatures 771m CRUTS3.0
- Historical Decadal Averages of Seasonal Mean Temperatures 771m CRUTS3.0
All products
tas_decadal_summaries_AK_771m_CRU_TS30_historical.zip (593 MB)
Day of freeze, thaw, length of growing season
Estimated Julian days of freeze and thaw (dof, dot) are calculated by assuming a linear change in temperature between consecutive months. Mean monthly temperatures are used to represent daily temperature on the 15th day of each month. When consecutive monthly midpoints have opposite sign temperatures, the day of transition (freeze or thaw) is the day between them on which temperature crosses zero degrees C. The length of growing season (logs) refers to the number of days between the days of freeze and thaw. More detailed explanations are discussed in the metadata.
Historical Derived Temperature Products - 771m CRU TS 3.1
Historical (1910–2009) derived temperature products from CRU TS 3.1 climate data, downscaled to 2 km via the delta method.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska |
Decadal summaries by month, year, and season
Metadata by product
- Historical Decadal Averages of Monthly Mean Temperatures 771m CRUTS3.1
- Historical Decadal Averages of Annual Mean Temperatures 771m CRUTS3.1
- Historical Decadal Averages of Seasonal Mean Temperatures 771m CRUTS3.1
All products
tas_decadal_summaries_AK_771m_CRU_TS31_historical.zip (707 MB)
Day of freeze, thaw, length of growing season
Estimated Julian days of freeze and thaw (dof, dot) are calculated by assuming a linear change in temperature between consecutive months. Mean monthly temperatures are used to represent daily temperature on the 15th day of each month. When consecutive monthly midpoints have opposite sign temperatures, the day of transition (freeze or thaw) is the day between them on which temperature crosses zero degrees C. The length of growing season (logs) refers to the number of days between the days of freeze and thaw. More detailed explanations are discussed in the metadata.
Historical Derived Precipitation Products - 771m CRU TS 3.0
Historical (1910–1999) derived precipitation products from CRUTS 3.0 climate data, downscaled to 771m via the delta method.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska |
Decadal summaries by month, year, and season
Metadata by product
- Historical Decadal Averages of Monthly Total Precipitation 771m CRUTS3.0
- Historical Decadal Averages of Annual Total Precipitation 771m CRUTS3.0
- Historical Decadal Averages of Seasonal Total Precipitation 771m CRUTS3.0
All products
pr_decadal_summaries_AK_771m_CRU_TS30_historical.zip (593 MB)
Historical Derived Precipitation Products - 771m CRU TS 3.1.01
Historical (1910-2009) derived precipitation products from CRU TS 3.1.01 climate data, downscaled to 2 km via the delta method.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska |
Decadal summaries by month, year, and season
Metadata by product
- Historical Decadal Averages of Monthly Total Precipitation 771m CRUTS3.1.01
- Historical Decadal Averages of Annual Total Precipitation 771m CRUTS3.1.01
- Historical Decadal Averages of Seasonal Total Precipitation 771m CRUTS3.1.01
All products
pr_decadal_summaries_AK_771m_CRU_TS31_historical.zip (655 MB)
Historical Monthly Temperature and Precipitation - 2 km CRU TS 3.0
Historical (1901-2009) monthly average temperature and total precipitation from CRU TS 3.0 climate data, downscaled to 2 km via the delta method.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2 km |
| Temporal Resolution | Monthly |
| Spatial Extent | Alaska and Western Canada (YT, BC, AB, SK, MB) |
Historical Monthly Temperature and Precipitation - 2 km CRU TS 3.1/3.1.01
Historical (1901-2009) monthly average temperature and total precipitation from CRU TS 3.1/3.1.01 climate data, downscaled to 2 km via the delta method.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2 km |
| Temporal Resolution | Monthly |
| Spatial Extent | Alaska and Western Canada (YT, BC, AB, SK, MB) |
Historical Derived Temperature Products - 2 km CRU TS 3.0
Historical (1910-2009) derived temperature products from CRU TS 3.0 climate data, downscaled to 2 km via the delta method.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2 km |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska and Western Canada (YT, BC, AB, SK, MB) |
Decadal summaries by month, year, and season
Metadata by product
- Historical Decadal Averages of Monthly Mean Temperatures 2km CRUTS3.0
- Historical Decadal Averages of Annual Mean Temperatures 2km CRUTS3.0
- Historical Decadal Averages of Seasonal Mean Temperatures 2km CRUTS3.0
All products
tas_decadal_summaries_AK_CAN_2km_CRU_TS30_historical.zip (331 MB)
Day of freeze, thaw, length of growing season
Estimated Julian days of freeze and thaw (dof, dot) are calculated by assuming a linear change in temperature between consecutive months. Mean monthly temperatures are used to represent daily temperature on the 15th day of each month. When consecutive monthly midpoints have opposite sign temperatures, the day of transition (freeze or thaw) is the day between them on which temperature crosses zero degrees C. The length of growing season (logs) refers to the number of days between the days of freeze and thaw. More detailed explanations are discussed in the metadata.
Historical Derived Temperature Products - 2 km CRU TS 3.1
Historical (1910-2009) derived temperature products from CRU TS 3.1 climate data, downscaled to 2 km via the delta method.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2 km |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska and Western Canada (YT, BC, AB, SK, MB) |
Decadal summaries by month, year, and season
Metadata by product
- Historical Decadal Averages of Monthly Mean Temperatures 2km CRUTS3.1
- Historical Decadal Averages of Annual Mean Temperatures 2km CRUTS3.1
- Historical Decadal Averages of Seasonal Mean Temperatures 2km CRUTS3.1
All products
tas_decadal_summaries_AK_CAN_2km_CRU_TS31_historical.zip (368 MB)
Day of freeze, thaw, length of growing season
Estimated Julian days of freeze and thaw (dof, dot) are calculated by assuming a linear change in temperature between consecutive months. Mean monthly temperatures are used to represent daily temperature on the 15th day of each month. When consecutive monthly midpoints have opposite sign temperatures, the day of transition (freeze or thaw) is the day between them on which temperature crosses zero degrees C. The length of growing season (logs) refers to the number of days between the days of freeze and thaw. More detailed explanations are discussed in the metadata.
Historical Derived Precipitation Products - 2 km CRU TS 3.0
Historical (1910–2009) derived precipitation products from CRUTS 3.0 climate data, downscaled to 2 km via the delta method.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2 km |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska and Western Canada (YT, BC, AB, SK, MB) |
Decadal summaries by month, year, and season
Metadata by product
- Historical Decadal Averages of Monthly Total Precipitation 2km CRUTS3.0
- Historical Decadal Averages of Annual Total Precipitation 2km CRUTS3.0
- Historical Decadal Averages of Seasonal Total Precipitation 2km CRUTS3.0
All products
pr_decadal_summaries_AK_CAN_2km_CRU_TS30_historical.zip (312 MB)
Historical Derived Precipitation Products - 2 km CRU TS 3.1.01
Historical (1910–2009) derived precipitation products from CRUTS 3.1.01 climate data, downscaled to 2 km via the delta method.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2 km |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska and Western Canada (YT, BC, AB, SK, MB) |
Decadal summaries by month, year, and season
Metadata by product
- Historical Decadal Averages of Monthly Total Precipitation 2km CRUTS3.1.01
- Historical Decadal Averages of Annual Total Precipitation 2km CRUTS3.1.01
- Historical Decadal Averages of Seasonal Total Precipitation 2km CRUTS3.1.01
All products
pr_decadal_summaries_AK_CAN_2km_CRU_TS31_historical.zip (345 MB)
Historical Monthly Potential Evapotranspiration - 2km CRUTS3.0
Historical (1901-2006) monthly total potential evapotranspiration utilizing CRU TS 3.0 climate data downscaled to 2 km via the delta method.
These potential evapotranspiration (PET) estimates were produced using the Hamon equation, which calculates PET as a function of temperature and day length. Potential evapotranspiration may also be influenced by cloud cover, humidity, and wind speed. The Hamon equation can not explicitly account for variability in these aspects of weather and climate, so it may over or underestimate changes in PET if humidity, cloud cover, or wind speeds change substantially. In addition, the Hamon equation was developed to calculate daily potential evapotranspiration, and so these estimates, based on monthly data, may differ from those calculated from daily data. We can also provide PET estimated by the Priestley-Taylor equation and standard equations for estimating the surface radiation budget from temperature. Priestley-Taylor data come with a much longer list of assumptions, including those that apply to the Hamon equation. Scripts used to produce both the Harmon and Priestley-Taylor versions are available online.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2km |
| Temporal Resolution | Monthly |
| Spatial Extent | Alaska |
Metadata
Metadata: Historical Monthly Total Potential Evapotranspiration 2km CRUTS3.0
Equations used to derive data: Hamon PET equations (PDF, 597KB)
Data
- 1901–2006 (726MB)
Historical Derived Potential Evapotranspiration - 2km CRUTS3.0
Historical (1910-1999) monthly total potential evapotranspiration utilizing CRU TS 3.0 climate data downscaled to 2 km via the delta method.
These potential evapotranspiration (PET) estimates were produced using the Hamon equation, which calculates PET as a function of temperature and day length. Potential evapotranspiration may also be influenced by cloud cover, humidity, and wind speed. The Hamon equation can not explicitly account for variability in these aspects of weather and climate, so it may over or underestimate changes in PET if humidity, cloud cover, or wind speeds change substantially. In addition, the Hamon equation was developed to calculate daily potential evapotranspiration, and so these estimates, based on monthly data, may differ from those calculated from daily data. We can also provide PET estimated by the Priestley-Taylor equation and standard equations for estimating the surface radiation budget from temperature. Priestley-Taylor data come with a much longer list of assumptions, including those that apply to the Hamon equation. Scripts used to produce both the Harmon and Priestley-Taylor versions are available online.
| Baseline Reference Climate | 1961–1990 PRISM |
|---|---|
| Spatial Resolution | 2km |
| Temporal Resolution | Decadal |
| Spatial Extent | Alaska |
Metadata by product
- Historical Decadal Averages of Monthly Total Potential Evapotranspiration 2km CRUTS3.0
- Historical Decadal Averages of Annual Total Potential Evapotranspiration 2km CRUTS3.0
- Historical Decadal Averages of Seasonal Total Potential Evapotranspiration 2km CRUTS3.0
Equations used to derive data: Hamon PET equations (PDF, 597KB)
All products by model and scenario
- 1910–1999 (181MB)
Historical Decadal Averages Of Monthly Snow-day Fraction 771m CRU TS 3.1
These snow-day fraction estimates were produced by applying equations relating decadal average monthly temperature to snow-day fraction to downscaled decadal average monthly temperature. Separate equations were used to model the relationship between decadal monthly average temperature and the fraction of wet days with snow for seven geographic regions in the state: Arctic, western Alaska, Interior, Cook Inlet, SW Islands, SW Interior, and the Gulf of Alaska coast.
Although the equations developed here provide a reasonable fit to the data, model evaluation demonstrated that some stations are consistently less well described by regional models than others. It is unclear why this occurs, but it is like related to localized climate conditions. Very few weather stations with long records are located above 500m elevation in Alaska, so the equations used here were developed primarily from low-elevation weather stations. It is not clear whether the equations will be completely appropriate in the mountains. Finally, these equations summarize a long-term monthly relationship between temperature and precipitation type that is the result of short-term weather variability. In using these equations to make projections of future snow, as assume that these relationships remain stable over time, and we do not know how accurate that assumption is.
Read the user’s guide for this data set (PDF, 1.5MB) for information on methodology and validation.
| Baseline Reference Climate | 1971–2000 PRISM |
|---|---|
| Spatial Resolution | 771m |
| Temporal Resolution | Monthly |
| Spatial Extent | Alaska |
Metadata by product
Metadata: Historical Decadal Averages Of Monthly Snow-day Fraction 771m CRUTS3.1
Data
1910-2009 (250MB)
Research Data
Data listed in this section are being developed specifically for several broad scale modeling projects. Overviews can be found on their respective project pages including all collaborators and funding sources.
These broad–scale modeling projects have very specific input data requirements. These include a 1×1km pixel resolution, spatial coverage across data poor regions of Alaska, the Yukon Territories, and parts of northern British Columbia, and temporal coverage of monthly data from the early 1900’s to 2100. In addition, because these datasets are being developed as input to specific models, they also require adherence to model specific requirements in order to produce plausible outputs. Because existing input data did not already exist at this level of detail, our approach has been to downscale the variables of interest to an intermediate resolution when available and then to apply common raster resampling methods down to 1×1km pixel sizes. Care has also been taken to keep the range of the data within accepted bounds and consistent across related variables.
This data is preliminary and is constantly being vetted and updated by our research group. Use of these datasets should be limited to these modeling projects only, but are shared here for stakeholder review and general communication of our data efforts.
Ancillary Data: Elevation, Slope, Slope Complexity, Aspect, Land Cover, Fire History (Burned Area)
| Data Set | Original Spatial Resolution | Final Spatial Resolution | Temporal Resolution |
|---|---|---|---|
| Elevation, Slope, Slope Complexity, Aspect | 2km | 1km | |
| Land Cover | 500m | 1km | 2005, but highly modified classes |
| Fire History (Burned Area) | vector format | 1km | 1917—2011 |
Metadata
Downloads
Ancillary IEM Data, 35MB
Historical Temperature
| Baseline Reference Climate | 1961–1990 |
|---|---|
| Original Spatial Resolution | 0.5° |
| Final Spatial Resolution | 1 km |
| Temporal Resolution | 1901 - 2009 |
Metadata
Downloads
Historical Temperature, 6.6 GB
Historical Precipitation
| Baseline Reference Climate | 1961–1990 |
|---|---|
| Original Spatial Resolution | 0.5° |
| Final Spatial Resolution | 1 km |
| Temporal Resolution | 1901 - 2009 |
Metadata
Downloads
Historical Precipitation, 3.0 GB
Historical Surface Downwelling Shortwave Radiation
| Baseline Reference Climate | 1961–1990 |
|---|---|
| Original Spatial Resolution | 0.5° |
| Final Spatial Resolution | 1 km |
| Temporal Resolution | 1901 - 2009 |
Metadata
Historical Surface Downwelling Shortwave Radiation
Downloads
Historical Vapor Pressure
| Baseline Reference Climate | 1961–1990 |
|---|---|
| Original Spatial Resolution | 0.5° |
| Final Spatial Resolution | 1 km |
| Temporal Resolution | 1901 - 2009 |
Metadata
Downloads
Historical Vapor Pressure, 2.4 GB
Projected Temperature
| Baseline Reference Climate | 1961–1990 |
|---|---|
| Original Spatial Resolution | 1.875–3.75° |
| Final Spatial Resolution | 1 km |
| Temporal Resolution | 2001–2100 |
Metadata
Downloads
- tas_mean_C_iem_cccma_cgcm3_1_sresa1b_2001_2100.zip, 6.2 GB
- tas_mean_C_iem_mpi_echam5_sresa1b_2001_2100.zip, 6.2 GB
- tas_mean_C_iem_cccma_cgcm3_1_sresa2_2001_2100.zip, 7.0 GB
- tas_mean_C_iem_mpi_echam5_sresa2_2001_2100.zip, 6.2 GB
- tas_mean_C_iem_cccma_cgcm3_1_sresb1_2001_2100.zip, 7.0 GB
- tas_mean_C_iem_mpi_echam5_sresb1_2001_2100.zip, 7.0 GB
Projected Precipitation
| Baseline Reference Climate | 1961–1990 |
|---|---|
| Original Spatial Resolution | 1.875–3.75° |
| Final Spatial Resolution | 1 km |
| Temporal Resolution | 2001–2100 |
Metadata
Downloads
- pr_total_mm_iem_cccma_cgcm3_1_sresa1b_2001_2100.zip, 6.1 GB
- pr_total_mm_iem_mpi_echam5_sresa1b_2001_2100.zip, 6.0 GB
- pr_total_mm_iem_cccma_cgcm3_1_sresa2_2001_2100.zip, 6.7 GB
- pr_total_mm_iem_mpi_echam5_sresa2_2001_2100.zip, 6.0 GB
- pr_total_mm_iem_cccma_cgcm3_1_sresb1_2001_2100.zip, 6.6 GB
- pr_total_mm_iem_mpi_echam5_sresb1_2001_2100.zip, 6.0 GB
Projected Surface Downwelling Shortwave Radiation
| Baseline Reference Climate | 1961–1990 |
|---|---|
| Original Spatial Resolution | 1.875–3.75° |
| Final Spatial Resolution | 1 km |
| Temporal Resolution | 2001–2100 |
Metadata
Historical Surface Downwelling Shortwave Radiation
Downloads
- rsds_mean_MJ-m2-d1_iem_cccma_cgcm3_1_sresa1b_2001_2100.zip, 5.8 GB
- rsds_mean_MJ-m2-d1_iem_mpi_echam5_sresa1b_2001_2100.zip, 5.8 GB
- rsds_mean_MJ-m2-d1_iem_cccma_cgcm3_1_sresa2_2001_2100.zip, 5.8 GB
- rsds_mean_MJ-m2-d1_iem_mpi_echam5_sresa2_2001_2100.zip, 5.8 GB
- rsds_mean_MJ-m2-d1_iem_cccma_cgcm3_1_sresb1_2001_2100.zip, 5.8 GB
- rsds_mean_MJ-m2-d1_iem_mpi_echam5_sresb1_2001_2100.zip, 5.8 GB
Projected Vapor Pressure
| Baseline Reference Climate | 1961–1990 |
|---|---|
| Original Spatial Resolution | 1.875–3.75° |
| Final Spatial Resolution | 1 km |
| Temporal Resolution | 2001–2100 |
Metadata
Downloads
- vap_mean_hPa_iem_cccma_cgcm3_1_sresa1b_2001_2100.zip, 2.2 GB
- vap_mean_hPa_iem_mpi_echam5_sresa1b_2001_2100.zip, 2.2 GB
- vap_mean_hPa_iem_cccma_cgcm3_1_sresa2_2001_2100.zip, 2.2 GB
- vap_mean_hPa_iem_mpi_echam5_sresa2_2001_2100.zip, 2.2 GB
- vap_mean_hPa_iem_cccma_cgcm3_1_sresb1_2001_2100.zip, 2.2 GB
- vap_mean_hPa_iem_mpi_echam5_sresb1_2001_2100.zip, 2.2 GB
Scenarios Network for Alaska & Arctic Planning
3352 College Road, Fairbanks AK 99709
nlfresco@alaska.edu | tel 907.474.2405 | fax 907.474.7151
