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URMA sky analysis issues impacting the NBM

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DV
Darren Van Cleave, modified 3 Years ago.

URMA sky analysis issues impacting the NBM

Youngling Posts: 37 Join Date: 1/8/14 Recent Posts

Hi, 

 

I posted this to the NBM feedback forum, but given that much of this is a result of the URMA I'm posting it here at well: https://docs.google.com/presentation/d/1XF8DYjmN5SKRMCD_YEeZGwaw7ADtzLg9RTLAxYHb1R4/edit?usp=sharing

 

-Darren

MM
Matthew Morris, modified 3 Years ago.

RE: URMA sky analysis issues impacting the NBM

Youngling Posts: 169 Join Date: 12/6/17 Recent Posts
Hi Darren,

Thanks for sharing this information.  We are taking a closer look at the issues and will keep you posted as we learn more.

-Matt

On Wed, Mar 2, 2022 at 4:04 PM VLab Notifications <VLab.Notifications@noaa.gov> wrote:

Hi, 

 

I posted this to the NBM feedback forum, but given that much of this is a result of the URMA I'm posting it here at well: https://docs.google.com/presentation/d/1XF8DYjmN5SKRMCD_YEeZGwaw7ADtzLg9RTLAxYHb1R4/edit?usp=sharing

 

-Darren


--
Darren Van Cleave RTMA/URMA Discussion Group Virtual Lab Forum https://vlab.noaa.gov/web/715073/discussions-forums-/-/message_boards/view_message/20963331VLab.Notifications@noaa.gov
MM
Matthew Morris, modified 3 Years ago.

RE: URMA sky analysis issues impacting the NBM

Youngling Posts: 169 Join Date: 12/6/17 Recent Posts
Hi Darren,
Regarding Issue #1, please see the attached slide deck for URMA graphics valid 14Z-16Z February 17th, 22nd, and 23rd.  In each case, the GOES sky cover observations are missing over Utah at 14Z [in addition to 15Z on 2/22], then reintroduced to the analysis.  The reintroduction of these observations is responsible for the quick change in analysis values between 14Z and 15Z, as the analysis is heavily influenced by these observations owing to their density.  Note: Such a change could also occur if the observations at 14Z were removed due to the QC introduced to RTMA/URMA in v2.8 [implemented July 2020].  With this QC, GOES Imager observations of < 30% are removed when the solar zenith angle exceeds 80 degrees.

We shared our findings concerning Issue #1 with the GOES Imager team, and the issue is stemming from the use of GOES-17 data.  In particular, the loop heat pipes are degraded and unable to cool the instrument.  The data quality was degraded considerably in mid-February, but has since improved.  However, we were informed that additional degradations will be seen in April.  We will hopefully see improvements to the RTMA/URMA sky cover products once GOES-18 goes live early next year.

For Issue #2, this appears to be due to the background fields, as you indicated.  Please see slides 21-24 for graphics valid 13Z February 19th, which show the cloud cover originating in the background fields [i.e., the HRRR 1-hr forecast].

Finally, for Issue #3, please see slides 25-31 for figures valid 13Z and 18Z 2/19/22.  The difference between the background (analysis) fields [18Z minus 13Z] are shown on slide 32 (33).  These show no systematic difference in the background and/or analysis values between these times.  Do you have specific examples of this behavior in URMA that we can investigate further?

Thanks,
Matt

On Thu, Mar 3, 2022 at 4:30 PM Matthew Morris - NOAA Affiliate <matthew.t.morris@noaa.gov> wrote:
Hi Darren,

Thanks for sharing this information.  We are taking a closer look at the issues and will keep you posted as we learn more.

-Matt

On Wed, Mar 2, 2022 at 4:04 PM VLab Notifications <VLab.Notifications@noaa.gov> wrote:

Hi, 

 

I posted this to the NBM feedback forum, but given that much of this is a result of the URMA I'm posting it here at well: https://docs.google.com/presentation/d/1XF8DYjmN5SKRMCD_YEeZGwaw7ADtzLg9RTLAxYHb1R4/edit?usp=sharing

 

-Darren


--
Darren Van Cleave RTMA/URMA Discussion Group Virtual Lab Forum https://vlab.noaa.gov/web/715073/discussions-forums-/-/message_boards/view_message/20963331VLab.Notifications@noaa.gov
DV
Darren Van Cleave, modified 3 Years ago.

RE: URMA sky analysis issues impacting the NBM

Youngling Posts: 37 Join Date: 1/8/14 Recent Posts

Appreciate the investigation Matt! I never thought of the loop heat pipe issue being involved, but that probably explains why it's a bigger headache for us in the West. I guess we'll have to live with it until GOES-18. For awareness, our forecasters (and likely other offices) are making extra edits to NBM Sky to remove the issue, which is not ideal. I would try to set up some sort of automated way to fix the NBM Sky, but hearing that it's related to the LHP issues makes it more complicated as it sounds as though the issue will go in and out in the URMA as a function of season, time, and LHP overheating, and thus the issue in the NBM would not be predictable.

 

By the way, am I interpreting your slides correctly that there is no GOES imager contribution to the Sky analysis overnight? I thought there was something using an IR channel to analyze overnight cloud cover, but it appears that is not the case. If so, that explains issue #3, which is that the overnight hours are missing the apparently-beneficial addition of GOES-imager correction showing clear skies. 

Eric Guillot, modified 3 Years ago.

RE: URMA sky analysis issues impacting the NBM

Youngling Posts: 5 Join Date: 4/22/13 Recent Posts
Hi Darren and Matt, just wanted to chime in here. Matt, I'm not sure I'm correctly understanding your description regarding the loop heat pipe problem. Are you saying that "bad" overheated imagery data is making its way into URMA? Or is the problem here that no data at all is making it in during overheating, and then when the imagery is better it comes back in immediately and causes sudden disjoints in the Sky product? I'm asking because if it's the former, I know that NESDIS has calculated pretty accurately exactly when to expect bad GOES-17 data throughout the year, therefore you could tell URMA to ignore that imagery during specific time periods? The TOWR-S team in the Office of Obs also calculates when the bad data begins in real time, which is another possible avenue to do this. Thanks!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Eric Guillot
Meteorologist, Analysis and Nowcast Branch (AFS11)
Analysis and Mission Support Division (AFS1)
Analyze, Forecast, and Support Office, National Weather Service
SSMC-2, Room 14111, 301-427-9250
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


On Tue, Mar 29, 2022 at 5:40 PM VLab Notifications <VLab.Notifications@noaa.gov> wrote:

Appreciate the investigation Matt! I never thought of the loop heat pipe issue being involved, but that probably explains why it's a bigger headache for us in the West. I guess we'll have to live with it until GOES-18. For awareness, our forecasters (and likely other offices) are making extra edits to NBM Sky to remove the issue, which is not ideal. I would try to set up some sort of automated way to fix the NBM Sky, but hearing that it's related to the LHP issues makes it more complicated as it sounds as though the issue will go in and out in the URMA as a function of season, time, and LHP overheating, and thus the issue in the NBM would not be predictable.

 

By the way, am I interpreting your slides correctly that there is no GOES imager contribution to the Sky analysis overnight? I thought there was something using an IR channel to analyze overnight cloud cover, but it appears that is not the case. If so, that explains issue #3, which is that the overnight hours are missing the apparently-beneficial addition of GOES-imager correction showing clear skies. 


--
Darren Van Cleave RTMA/URMA Discussion Group Virtual Lab Forum https://vlab.noaa.gov/web/715073/discussions-forums-/-/message_boards/view_message/21430956VLab.Notifications@noaa.gov
MM
Matthew Morris, modified 3 Years ago.

RE: URMA sky analysis issues impacting the NBM

Youngling Posts: 169 Join Date: 12/6/17 Recent Posts
Hi Darren,

Hopefully, we will see improvements to the RTMA/URMA sky cover products once GOES-18 goes live early next year.  In the case of 19 February 2022, the GOES Imager observations were only missing over the western US for the 13Z and 14Z cycles.  Thus, the GOES Imager data doesn’t appear to be directly responsible for Issue #3.

Hi Eric,

Our understanding is that the LHP issues will result in missing observations; however, the observation quality is often suspect when the reporting resumes.  The metadata from NESDIS would be useful to the ob QC performed at the obsproc level, and we will explore its use as we transition to 3D-RTMA.

Thanks,
Matt

On Wed, Mar 30, 2022 at 9:40 AM VLab Notifications <VLab.Notifications@noaa.gov> wrote:
Hi Darren and Matt, just wanted to chime in here. Matt, I'm not sure I'm correctly understanding your description regarding the loop heat pipe problem. Are you saying that "bad" overheated imagery data is making its way into URMA? Or is the problem here that no data at all is making it in during overheating, and then when the imagery is better it comes back in immediately and causes sudden disjoints in the Sky product? I'm asking because if it's the former, I know that NESDIS has calculated pretty accurately exactly when to expect bad GOES-17 data throughout the year, therefore you could tell URMA to ignore that imagery during specific time periods? The TOWR-S team in the Office of Obs also calculates when the bad data begins in real time, which is another possible avenue to do this. Thanks!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Eric Guillot
Meteorologist, Analysis and Nowcast Branch (AFS11)
Analysis and Mission Support Division (AFS1)
Analyze, Forecast, and Support Office, National Weather Service
SSMC-2, Room 14111, 301-427-9250
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


On Tue, Mar 29, 2022 at 5:40 PM VLab Notifications <VLab.Notifications@noaa.gov> wrote:

Appreciate the investigation Matt! I never thought of the loop heat pipe issue being involved, but that probably explains why it's a bigger headache for us in the West. I guess we'll have to live with it until GOES-18. For awareness, our forecasters (and likely other offices) are making extra edits to NBM Sky to remove the issue, which is not ideal. I would try to set up some sort of automated way to fix the NBM Sky, but hearing that it's related to the LHP issues makes it more complicated as it sounds as though the issue will go in and out in the URMA as a function of season, time, and LHP overheating, and thus the issue in the NBM would not be predictable.

 

By the way, am I interpreting your slides correctly that there is no GOES imager contribution to the Sky analysis overnight? I thought there was something using an IR channel to analyze overnight cloud cover, but it appears that is not the case. If so, that explains issue #3, which is that the overnight hours are missing the apparently-beneficial addition of GOES-imager correction showing clear skies. 


--
Darren Van Cleave RTMA/URMA Discussion Group Virtual Lab Forum https://vlab.noaa.gov/web/715073/discussions-forums-/-/message_boards/view_message/21430956VLab.Notifications@noaa.gov

--
Eric Guillot RTMA/URMA Discussion Group Virtual Lab Forum http://vlab.noaa.gov/web/715073/home/-/message_boards/view_message/21441691VLab.Notifications@noaa.gov