Historical Monthly Surface Downwelling Shortwave Radiation 1km CRU TS

This set of files constitutes a time series of downscaled projections of mean Surface Downwelling Shortwave Radiation (RSDS, units=MJ-m2-d1) at a 1km spatial scale at a monthly time-step.

This data has been prepared as model input for the Integrated Ecosystem Model (IEM). The data constitute the result of a downscaling procedure using the Climatic Research Unit (CRU) TS 4.0 (0.5 decimal degree spatial resolution) monthly time series and CRU TS 2.0 (1961-1990,10 min spatial resolution) global climatology data.

2 versions are provided that correspond to different versions of CRU data.
CRU TS 3.1: 1901-2009
CRU TS 4.0: 1901-2015

Methods of creating downscaled surface downwelling shortwave radiation data:

  1. Input baseline climatology girr data were calculated using an equation from Allen et al. (1998) at a monthly timestep, which is used to represent the historical period rsds data at 1km spatial scale. GIRR refers to top of the atmosphere solar radiation

  2. Climate of the 20th Century (20c3m) cloud cover data from CRU TS3.x for the period 1961-1990 are used to create a climatology at the input resolution of the given model.

  3. The above 1961-1990 monthly cloud cover climatology series is used to calculate the proportional anomalies for the time series of cloud cover data, used as input to delta downscaling procedure.

  4. Data limitations at the downscaled resolution required the calculation of cloud cover from sunshine percent from the CRU TS2.0 1961-1990 climatology data to use as a baseline for downscaling.

  5. The anomalies calculated above are then interpolated using a spline interpolation procedure to a 10min spatial scale grid.

  6. The proportional anomalies are then multiplied by the baseline 10min calculated cloud cover 1961-1990 grids to produce a downscaled cloud cover time series.

  7. The downscaled cloud cover timeseries is then used to calculate nirr (rsds) from the girr and downscaled cloud cover using the following equation: nirr = monthly_girr * (0.251 + (0.509 * (1.0 - cloud_cover/100))) NIRR refers to surface solar or shortwave radiation

Downscaling:
These files are bias corrected and downscaled via the delta method using Climatic Research Unit (CRU) CRU TS 2.0 1961-1990 Climatology data (10min Spatial Resolution) as baseline climate.

For more detailed information on base input data (GCMs, historical data), emmission scenarios, the downscaling process, or uncertainty, please go to http://www.snap.uaf.edu/

Data and Resources

Additional Info

Spatial resolution

1000 meters

Temporal extent

Start date: January 1901

End date: December 2015

Credits

The following people worked on producing this data set:

  • Tom Kurkowski
  • Stephanie McAfee
  • Michael Lindgren
  • This research is funded by the Arctic Landscape Conservation Cooperative, Western Alaska Landscape Conservation Cooperative, and Northwest Boreal Landscape Conservation Cooperative (LCCs) and the Alaska Climate Science Center.
Field Value
Source http://data.snap.uaf.edu/data/IEM/Inputs/historical/radiation/
Maintainer Tom Kurkowski
Version 1.0.0
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contact-email takurkowski@alaska.edu
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credits ["Tom Kurkowski", "Stephanie McAfee", "Michael Lindgren", "This research is funded by the Arctic Landscape Conservation Cooperative, Western Alaska Landscape Conservation Cooperative, and Northwest Boreal Landscape Conservation Cooperative (LCCs) and the Alaska Climate Science Center."]
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temporal-extent-begin 1901-01-15T00:00:00
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