Open fstuerzl opened 2 years ago
Variables 12001 and 12002 are included in OSCAR/Requirements, so I suggest to use the definitions provided there:
Name | Definition |
---|---|
Total lightning density | Total number of detected flashes in the corresponding time interval and the space unit. The space unit (grid box) should be equal to the horizontal resolution and the accumulation time to the observing cycle |
Cloud to Ground lightning density | Number of detected cloud-to-ground flashes in the corresponding time interval and the space unit. The space unit (grid box) should be equal to the horizontal resolution and the accumulation time to the observing cycle |
subset of issue #190
I have reached out to a colleague on this one.
https://library.wmo.int/?lvl=notice_display&id=220 may also contain some useful descriptions.
OSCAR/Requirements currently contains two lightning variables:
And here are some further comments:
12001-12002) Optionally, we may replace the name "Total lightning density" by "Total lightning flash density", and "Lightning density cloud-to-ground" by "Cloud-to-ground lightning flash density", to make it clear we are speaking of flashes. The sentence: "The space unit (grid box) should be equal to the horizontal resolution and the accumulation time to the observing cycle" may not be appropriate for lightning data. Indeed, lightning data do not have a uniquely defined horizontal resolution (the localization accuracy varies for each event) nor observing cycle (lightning events are detected in real time). So, there is no unique space and time unit for defining the lighting density. A typical definition of lightning density is #events/km^2/min A last comment: we may also consider adding "lighing discharge" densities; in this case, we don't speak of flashes anymore, but of their subcomponents (strokes and pulses). These correspond e.g. to the lightning events that are plotted in NinJo.
257-) Lightning energy is difficult to measure, and is not, for instance, part of the data we receive from Météorage. Instead, we receive the measurement of the lightning current intensity (measured in kA). It may be meaningful to add the current intensity as a new voice of the lightning vocabulary, or even to replace the lightning energy by it.
259-) As you see by the description, the concept of "lighting discharge rate" is not unique, as it can be applied to different contexts (regions, thunderstorm cells,...). Does it makes sense to keep this voice? Or shall we specify it better?
432-433) We may replace "lightning" by "lightning discharge", so that it is clear we are not speaking of lightning flashes. Notice: we receive lightning data on the whole COSMO-Alps domain. The stations mentioned here (I presume, in our case, Swissmetnet stations), are not responsible for the lightning detection (instead, a network of Météorage antennas makes the detection). For historical and climatological reasons, we however classify lightning data depending on the distance from each SwissMetNet station. I cannot judge whether it makes sense to keep these voices here, but it must be clear that these parameters are somehow "artificial".
Best regards,
Simone Balmelli
@sibalm @joergklausen @amilan17 . Thanks for these explanations. I suggest that we also check with experts on lightning imagery from satellites, as I know that the processing of these data (and hence potentially the data dissemination) uses many of these concepts. WMO Space Programme will have the appropriate contacts.
https://github.com/wmo-im/tt-wigosmd/wiki/Meeting-2022.09.22 notes:
https://github.com/wmo-im/tt-wigosmd/wiki/2022.10.06-TT-WIGOSMD meeting notes:
no progress yet
Steve Goodman from NOAA can provide some feedback after October
Definitions provided by @sibalm make sense. Still need to agree on remaining comments, paraphrased here:
Need comments from @hpohjolawmo and @gaochen-larc (Will Mc Carty) and @joergklausen (Urs Germann)
I reached out to Urs Germann, but he doesn't feel compenent enough to provide additional insight.
https://github.com/wmo-im/tt-wigosmd/wiki/2022.11.03-TT-WISOSMD notes: @amilan17: Heikki will provide some feedback soon
@sibalm thank you for your contributions to the definitions of these proposals. Can you please update your profile with your full name and affiliation? I like to document who has contributed to proposals for amendments when submitting for approval. Thanks. Anna (WMO Secretariat)
Proposal updated. Need review by @hpohjolawmo (Heikki) and @gaochen-larc (Will McCarthy)
@joergklausen I don't see any changes in the proposal summary. Am I missing something?
@joergklausen I don't see any changes in the proposal summary. Am I missing something?
I had to redo this, left the page before updating, apparently ...
Review from Heikki, Steve Goodman and Pekka Rossi
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If your objective is to system agnostic then perhaps fewer codes is better, for example,
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https://github.com/wmo-im/tt-wigosmd/wiki/2022.11.22-TT-WIGOSMD notes:
@joergklausen will reach out to collaborators to see if they are willing to form a temporary editing team to finalize this proposal such that it represents sattelite and ground observations.
@sibalm thank you for your contributions to the definitions of these proposals. Can you please update your profile with your full name and affiliation? I like to document who has contributed to proposals for amendments when submitting for approval. Thanks. Anna (WMO Secretariat)
@amilan17 I have updated my profile. Please tell me if you need more information. Thank you!
https://github.com/wmo-im/tt-wigosmd/wiki/2023.02.16-TT-WIGOSMD notes:
Anna will follow up with organizing a side meeting with specific experts.
I was invited to join this conversation Gao Chen as a result of a side conversation with @tjlang, who I will take the liberty of quoting:
I think lightning flash extent density (FED) may be a useful addition to the WMO metadata standards. FED, which is calculable from anything that measures the horizontal extent of lightning flashes (including LIS, GLM, MTG-LI, and Lightning Mapping Arrays), is very helpful for understanding where lightning occurs.
I agree with this idea. It would be useful to distinguish between quantities that arise from lighting mapping (which accounts for the spatial extent of lighting discharges) and point-location measurements.
For point-location and mapped flashes, the respective terms in my mind would be “flash density" and "flash extent density,” as suggested by Timothy.
We could also add “flash area,” which now has use in US NWS operations, and is another basic measurement made by lightning mapping systems.
Note that flash density has units of inverse area inverse time (e.g., number of flashes s^-1 km^-2). Flash extent density (FED) is similar except here you count number of flash portions that pass thru a given area in a given time. So even if the flash centroids are elsewhere you can have portions of them pass thru a given area in a given time as the lightning channels propagate. Flash area is just basic area units (e.g., km^2).
@amilan17 Please set up meeting with all stakeholders mentioned in issue. Suggestion: 28 March or 30 March. Thanks
https://github.com/wmo-im/tt-wigosmd/wiki/2023-03-17-TT-WIGOSMD notes: @amilan17 set up meeting with stakeholders
IMHO, the only way forward here is to organize this meeting suggested earlier.
https://github.com/wmo-im/tt-wigosmd/wiki/2023.06.01-TT-WIGOSMD notes:
@amilan17 Setup a MS Teams meeting with Tim Lang, John Eyre, Simone Balmelli, Heikki
@joergklausen has asked me to give this action new momentum because it seems almost solved but not really finalized. Taking notice of all the comments, I have concluded that in fact the discussion is much broader and I can split this issue into the following activities:
So, in order to speed up, it may be better to finalized first activity no. 1 and than follow up with the others.
w/r 1: For the current proposal (see on top), I think acceptance is straightforward at present. One suggestion is still open (see comment by @joergklausen: 432 (direction) and 433 (distance): Suggestion to replace "lightning" by "lightning discharge", so that it is clear we are not speaking of lightning flashes.
w/r 2: mentioned in the comment by @deeplycloudy and @tjlang a new notation is suggested: lightning flash extent density (FED). However the notations with lightning (flash) density are comparable and distinction between a new notation and the existing ones must be clear to avoid confusion.
w/r 3: This would be a separate activity, dedicated to experts working on lightning observations by satellites. I recommend to take note of the new (2021) Volume IV of the GIMO (WMO-No. 8) on Space-based Observations and with paragraphs describing the technology to determine and observe lightning from space. For an excerpt from this Volume on lightning, see: 8_IV_2021_en(Excerpt on Lightning).pdf
w/r 4: A overall review of the entire code library is proposed. It will help to improve consistency, although such a review may result in a major revision of the present naming convention (flash, discharge, etc.). Although the WMDR codes should be technology free, most notations are linked to available observation techniques. So, this review will be quite a challenge and time consuming. For this activity I recommend to take note of the new version of the chapter on Lightning Detection in GIMO, Volume III (WMO-No. 8). The latest version is approved by EC-76 mid 2023, see: 8_III_6_en_LCP.pdf
So, I kindly request all contributors to give there comments on this proposal, in particular @sibalm (Simone Balmelli, MeteoSwiss), @hpohjolawmo (Heikki, WMO), @gaochen-larc (Will Mc Carty), @tjlang (Timothy Lang), and @deeplycloudy (Eric Bruning).
https://github.com/wmo-im/tt-wigosmd/wiki/2024.02.15-TT-WIGOSMD notes: Jitze added a proposal in GH (see above) with no comment yet; will follow through with an email;
@meulenvd @joergklausen @amilan17 This Issue is still in need of expert review, and I hope that contacts established by Jitze will achieve this. At the end of the day, we need a set of names and definitions that are acceptable to both space-based and surface-based observing communities, because they are both trying to provide observational information on the same geophysical phenomena. However, it would be acceptable for some variables to relate only to space-based or only to surface-based observations (and, in these cases, the definitions should make this clear).
@joergklausen @amilan17 @JREyre Separate E-mail send to @sibalm @hpohjolawmo @gaochen-larc @tjlang @deeplycloudy, requesting comments, see e-mail (2024-02-19) issue 391.pdf
https://github.com/wmo-im/tt-wigosmd/wiki/2024.04.09%E2%80%90TT%E2%80%90WIGOSMD notes: @amilan17 to organize a meeting with relevant parties; John recommends just having a meeting with key experts;
@meulenvd and I agree to move forward with step 1 (see attached). If/when we need other codes, new amendments can be proposed at that time. The original purpose here was to add missing definitions.
see list of steps w/r step 2 and 3 (introduction of new or alternative notations in line with satellite based products) the following information on
might be of interest:
https://github.com/wmo-im/tt-wigosmd/wiki/2024.05.16%E2%80%90TT%E2%80%90WIGOSMD notes: team agrees to move forward with proposal as is.
@joergklausen branch is updated
Proposal Summary
Please consult the Guidance and use the following structure for new issues. Note, the content in this initial comment box is subject to modification to document the final decisions or to provide more details as needed.
Summary and Purpose
Add definitions to lightning variables.
Proposal
new
deprecate
Reason
Every entry in the WMDR code lists should have a useful definition.
Stakeholder(s)
[include names and emails or handles of individuals or groups that introduced the proposal]
Consultations
@sibalm (Simone Balmelli, MeteoSwiss)
@hpohjolawmo (Heikki, WMO)
@gaochen-larc (Will Mc Carty)
@tjlang (Timothy Lang)
@deeplycloudy (Eric Bruning)
@... (Steve Goodman)
@... (Pekka Rossi)
Context
[include references to manuals or guides that are reviewed to ensure alignment, if proposal differs then document how and why]
Expected Impact of Change
LOW