Showing posts with label Wunderground. Show all posts
Showing posts with label Wunderground. Show all posts

Oct 12, 2013

Discrepancies in actual measurements of very severe Cyclonic storm Phailin

Phailin makes landfall approximately around 7.30 Pm Indian Standard Time (IST) according to some International satellite estimates, and it was also reported in some section of the local Indian media that landfall did took place at the time, but was unconfirmed by IMD.

Also, the location of the landfall reported was also subject to differences. 

Firstly, it was reported in the media that the landfall took place in Srikakulam in Andhra Pradesh. But those reports were not confirmed by IMD.

And later on IMD officially announced that the landfall took place around 8 Pm IST and in Gopalpur, Odisha.

But there were also differences in reporting the wind speed of the Cyclone Phailin, with Joint Typhoon Warning Center rating it as a category 4 with wind speeds approximately 140 mph approximately 225 km/hr.

But the IMD satellite readings were 25 Km/hr different.

Based on IMD's calculations, the wind speed recorded was 200 km/hr with wind gusts upto 225 Km/hr.

Why was there such a difference in calculations between JTWC and IMD?

This difference in calculation could be found at this blog update by Dr Jeff from Wunderground.

Measurements always carry an element of error but that is negligible, but differences in important measurement data that does matter, need to be studied and rectified.

Satellite estimates confirming the timing of landfall can be found at this status update  i.e., the storm actually made the landfall at 7.30 Pm IST. 

Satellite pictures of NOAA confirms this fact at this link

Now, if you have gone through the blog page of Dr Jeff Masters from Wunderground, it is understandable that methods used to determine the measurements in tracking the wind speed of the cyclone vary between JTWC and IMD.

It is mentioned in the report by Dr Jeff that the Indian system takes average of the readings calculated at a duration interval of every 3 minutes that would lessen the actual readings by almost by 2%.

And JTWC's calculation are based on per minute duration of time. 

Since both the methods of measurement depend on satellite imagery and data, it is hard to say which one is more correct.

In my personal view, this would give a more clear and precise picture of what is actually happening with a weather system of such a magnitude and power.

Update : 

Vishakhapatnam in Andhra Pradesh remains unaffected by the Cyclone Phailin.

Srikakulam is out of Power. No casualties reported from Andhra Pradesh so far.

The  path of Cyclone Phailin has now veered north towards Gangetic Plains with reported wind speeds of 100 km/hr.

Heavy to very heavy rainfall reported all along the Odisha coast.

Phailin's intensity found to be of level 6 according to IMD updates.

Gopalpur in Odisha bearing the brunt with electricity poles and trees uprooted. 

Cyclone Phailin has affected communication towers and power supply in Odisha.

20 sailors are reported to be stranded off AP coast.  

Reports of MV Bingo and other unknown vessel sinking due to bad weather, resecue and relief efforts could not be carried yet.

MV Bingo was carrying a crew of 10 Chinese sailors and an Indonesian.

Update :Oct 15

17 Chinese crew and a Myanmarese national caught in the rough waters are reported to be found by rescue mission off the coast of Odisha district. 

The crew embarked on the life boat when their ship carrying Iron ore to China, began sinking.

The crew reportedly survived rough seas for almost 36 hours. And were able to contact Chinese authorities through a single mobile phone left with them.

After being contacted, the Indian authorities launched a search mission tracking their GPRS signal and rescued them from the sea.  

18 sailors of MV Bingo rescued from the sea: Indian Express