This is an extract of the technical bulletin we issue to our WindDesk - Predict and WindDesk - Monitoring customers when either a) global remote sensing data is updated or revised or b) material changes occurred at their measurement site. We wanted to share some of the non-project specific insights below.

Issue with NASA MERRA-2 September 2020 data

NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) informed users on 31 Oct 2020 with regards to an issue with MERRA-2 September 2020 data (prefixed as MERRA2_400).  NASA subsequently re-processed and released an updated version of the data on 6 Nov 2020 (prefixed as MERRA2_401) and has advised users not to use to original data in version 400. We have updated our internal system to the newest dataset. We have also re-performed all wind resource and energy calculations for the following measurement campaigns we are monitoring for you:

Mean wind speed and energy impact on your projects

Dataset difference globally

While the details of the issue have yet to be made known to data users, we analyzed the old and new data for various regions in the world:

• The monthly-averaged wind speed at the 50-m level differs between 0m/s to 0.5m/s for most places, up to a peak difference of 0.9m/s [Figure 1].
• Areas with significant changes are located at latitudes between -15°and 25°, and -90° and -60°.
• The magnitude of the monthly-averaged wind speed difference increased with increasing reference height (2-m, 10-m, 50-m) [Figure 1 to Figure 3].

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Dataset differences in specific regions

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If you would like to receive dataset alerts or technical bulletins like this, please drop me a line at jianhao@traverse.ai .

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