Clearness Index Data

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Clearness Index Data

by EarthdataForumContributor » Tue May 05, 2020 9:24 am America/New_York

Hey can we Clearness index data for the Austin area on a monthly basis from 1985 to the most recent data?

ASDC - mcook
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Re: Clearness Index Data

by ASDC - mcook » Tue May 05, 2020 9:25 am America/New_York

Thank you for contacting us with your inquiry about Clearness Index data.

Clearness Index data are available from the Prediction Of Worldwide Energy Resource (POWER) website:

For your convenience we provided instructions for obtaining the data for research.

Solar and meteorological parameters can be accessed in the POWER web site via the Data Access Viewer (DAV) at When the DAV page opens you may click the “Access Data” box and/or check the “Do not show ...” box to avoid loading the splash Page on subsequent visits.
1. In the DAV page that is now visible, in Section 1 select "SSE-Renewable Energy" for the desired data parameters.
2. Choose "Climatology" in Section 2.
a. Note that if Climatology time period is selected in Section 2, there is no need to enter a time period in section 4 since by default monthly values are averaged over the climatological time period. (22-year period, July 1983 – June 2005)
3. Enter the site latitude and longitude in Section 3.
4. In Section 4, skip this step.
5. In Section 5, Select Output File Format.
6. In Section 6, Choose the "Sizing and Pointing Of Solar Panels and for Solar Thermal Applications".
Each folder can be opened by clicking on the intersection of the horizontal and vertical branch associated with each folder. Individual data parameters are selected/deselected by clicking on each parameters or all parameters in a folder can be selected/deselected by clicking on the folder itself.
7. Click the “Submit” button in Section 7. The resulting page will provide time series plots of the selected data parameters. To download data in the previously selected format click the appropriate box under the "Output Files".
You may also download all data parameters using API calls described at

We would like to direct your attention to the new POWER FAQ's. It is a quick tutorial for finding your way around the new POWER website.

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