Big hole around Gulf of Thailand

[NRDcubed]

I’ve spent the last couple weeks in Thailand, particularly Pattaya area And there seems to be a huge hole in detection over the Gulf of Thailand. Sitting on the beach looking west almost nightly, you can see cloud to cloud lightning Which could be very far because there is no sound But on the map, even 500 miles away there are no hits. Furthermore, almost daily there is cloud to ground strikes with no hit.

[GeezerD]

As I understand it (I have gotten a detector just this year) Cloud to Cloud lightning (IC, Intra-Cloud) has a couple of characteristics that make it harder for the Blitzortung network to detect or locate.

First is the polarization of the transmission: the antennas used are best at vertically polarized signals, and CG (Cloud-Ground) strike are what transmit most efficiently vertically polarized. These CG strikes also have the most efficient ground-wave propagation.

I'm unfamiliar with the algorithm that is used to identify particular strikes at multiple stations, but I suspect lightning transmission signatures are more directionally invariant with CG strikes than IC strikes.

South America and Africa have really low location rates as well, considering how well represented they are with other lightning detection networks. Blitzortung seems very biased towards northern and and western hemisphere detections.

D

[cutty]

I’ve spent the last couple weeks in Thailand, particularly Pattaya area And there seems to be a huge hole in detection over the Gulf of Thailand. Sitting on the beach looking west almost nightly, you can see cloud to cloud lightning Which could be very far because there is no sound But on the map, even 500 miles away there are no hits. Furthermore, almost daily there is cloud to ground strikes with no hit.

As I understand it (I have gotten a detector just this year) Cloud to Cloud lightning (IC, Intra-Cloud) has a couple of characteristics that make it harder for the Blitzortung network to detect or locate.

First is the polarization of the transmission: the antennas used are best at vertically polarized signals, and CG (Cloud-Ground) strike are what transmit most efficiently vertically polarized. These CG strikes also have the most efficient ground-wave propagation.

I'm unfamiliar with the algorithm that is used to identify particular strikes at multiple stations, but I suspect lightning transmission signatures are more directionally invariant with CG strikes than IC strikes.

South America and Africa have really low location rates as well, considering how well represented they are with other lightning detection networks. Blitzortung seems very biased towards northern and and western hemisphere detections.

D

The ANSWER is quite simple, actually:
   

...and about a dozen DOA...

[oppedahl]

I’ve spent the last couple weeks in Thailand, particularly Pattaya area. And there seems to be a huge hole in detection over the Gulf of Thailand. Sitting on the beach looking west almost nightly, you can see cloud to cloud lightning Which could be very far because there is no sound But on the map, even 500 miles away there are no hits. Furthermore, almost daily there is cloud to ground strikes with no hit.

Yes you are right.  I looked at https://map.blitzortung.org/#5/9.21/104.38 to see where there are active Blitzortung stations.  All of the stations that immediately surround the Gulf are presently "offline".  The way you can tell this is to look at the curved brackets that surround the colored dot of the station.  The eleven or so stations that immediately surround the Gulf all have curved brackets that are gray. 

• There have been five stations in Thailand and all are presently offline.
  
• There have been two stations in Cambodia and all are presently offline.
  
• There has been one station in southern Vietnam and it is presently offline.
  
• There has been one station in southern Myanmar and it is presently offline.
  
• There have been three stations in nearby parts of Malaysia and all are presently offline.
  

It would of course be most welcome if some of those stations could be returned to online status.  This could help with the hole in detection that you describe.

Every now and then, a lightning strike in the Gulf of Thailand will get detected using signals from other Blitzortung stations that are much further away.  For example just a few hours ago this strike was detected:  2025-09-16 20:39:17.239059456 .

With the help of forum member Robo I was able to learn more about how the Blitzortung system detected and localized that particular strike.  One Blitzortung station that helped to find that strike was the sole active station in Vietnam (2243).  Another that helped was in the Philippines (2710).   Eighteen stations in Japan helped to locate the strike.  And a station in Omsk, Russia (2769) helped -- that station was about 1700 km away from the strike.

This strike that I happened to notice on the map was, I suspect, a rarity for the location.  I bet there are lots of strikes in the Gulf of Thailand that don't get detected.

[robo]

The ANSWER is quite simple, actually:

I bet some of the station operators whose stations are offline haven't even noticed this yet. We should ask Egon to finally implement an email notification when a station is offline for more than an hour.