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10m Wind Speed in KML Files

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David Bonnette, modified 4 Years ago.

10m Wind Speed in KML Files

Youngling Posts: 4 Join Date: 3/31/18 Recent Posts

Howdy! We have a consistent low wind speed bias in the DFW Metroplex (mostly the eastern half due to so many poorly sighted APRSWX/CWOP sites) and I was trying to do QC on the mesonet obs that still need blacklisting. After a lot of frustration, my SOO realized that the BG and ANL values are different depending on the sensor height.

 

Could there be a field added to the KML files that lists the final 10m wind speed value? I know we can take the ANL/FACTW values to get the final 10m speed, but it would make QC much easier if that was done for us in the KML.

 

Thank you!

-David Bonnette

WFO FWD

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MM
Matthew Morris, modified 4 Years ago.

RE: 10m Wind Speed in KML Files

Youngling Posts: 174 Join Date: 12/6/17 Recent Posts
Hi David,

The observation, background, and analysis values listed in the KML files are all currently valid at the observation height (e.g., 2-m for CWOP stations).  We will be updating the KML files to list the background and analysis values valid at 10-m AGL.

Once this change is made, the background/analysis and observation values will be valid at different heights.  To combat this, we will also be adding the adjusted observation value (valid at 10-m AGL) to the KML files.

We will let you know once these changes are made.  Please let us know if you have any other questions.

Thanks,
Matt

On Tue, Nov 17, 2020 at 1:53 PM VLab Notifications <VLab.Notifications@noaa.gov> wrote:

Howdy! We have a consistent low wind speed bias in the DFW Metroplex (mostly the eastern half due to so many poorly sighted APRSWX/CWOP sites) and I was trying to do QC on the mesonet obs that still need blacklisting. After a lot of frustration, my SOO realized that the BG and ANL values are different depending on the sensor height.

 

Could there be a field added to the KML files that lists the final 10m wind speed value? I know we can take the ANL/FACTW values to get the final 10m speed, but it would make QC much easier if that was done for us in the KML.

 

Thank you!

-David Bonnette

WFO FWD


--
David Bonnette RTMA/URMA Discussion Group Virtual Lab Forum https://vlab.noaa.gov/web/715073/discussions-forums-/-/message_boards/view_message/12580022 VLab.Notifications@noaa.gov

MM
Matthew Morris, modified 4 Years ago.

RE: 10m Wind Speed in KML Files

Youngling Posts: 174 Join Date: 12/6/17 Recent Posts
Hi David,

The URMA KML observation files for wind speed & gust were updated with this morning's 06Z URMA analysis.  The "BG VALUE", "ITER 2", "ITER 3", and "ANL VALUE" entries are now adjusted to a height of 10-m AGL (computed by dividing the original value by factw).  As a reminder, those files can be found here.

In order for the KML files to provide a complete picture, we also added an additional row to the KML files, namely the adjusted wind speed observation valid at 10-m AGL (labeled as "ADJUSTED OB VALUE").  Note that the GSI adjusts the height of the background value to match the height of the observation (ges_10m * factw), then computes the observation increment valid at observation height (e.g., 2-m for CWOP stations).  The computed increment is then assumed to be valid at 10-m AGL.  In other words, the observation itself is not adjusted in the assimilation procedure.

In order to preserve the observation increment, the adjusted observation is computed as: ob_adj = ob_raw + FG*(1-factw), where FG is the first guess value.

We hope these changes are beneficial for your quality control efforts.  Please let us know if you have any other questions.

Thanks,
Matt

On Fri, Nov 20, 2020 at 9:38 AM VLab Notifications <VLab.Notifications@noaa.gov> wrote:
Hi David,

The observation, background, and analysis values listed in the KML files are all currently valid at the observation height (e.g., 2-m for CWOP stations).  We will be updating the KML files to list the background and analysis values valid at 10-m AGL.

Once this change is made, the background/analysis and observation values will be valid at different heights.  To combat this, we will also be adding the adjusted observation value (valid at 10-m AGL) to the KML files.

We will let you know once these changes are made.  Please let us know if you have any other questions.

Thanks,
Matt

On Tue, Nov 17, 2020 at 1:53 PM VLab Notifications <VLab.Notifications@noaa.gov> wrote:

Howdy! We have a consistent low wind speed bias in the DFW Metroplex (mostly the eastern half due to so many poorly sighted APRSWX/CWOP sites) and I was trying to do QC on the mesonet obs that still need blacklisting. After a lot of frustration, my SOO realized that the BG and ANL values are different depending on the sensor height.

 

Could there be a field added to the KML files that lists the final 10m wind speed value? I know we can take the ANL/FACTW values to get the final 10m speed, but it would make QC much easier if that was done for us in the KML.

 

Thank you!

-David Bonnette

WFO FWD


--
David Bonnette RTMA/URMA Discussion Group Virtual Lab Forum https://vlab.noaa.gov/web/715073/discussions-forums-/-/message_boards/view_message/12580022 VLab.Notifications@noaa.gov


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Matthew Morris RTMA/URMA Discussion Group Virtual Lab Forum http://vlab.noaa.gov/web/715073/home/-/message_boards/view_message/12619453 VLab.Notifications@noaa.gov