Measuring super typhoon wind speeds with ASCAT
7 July 2014 00:40 UTC and 6 August 2015 00:35 UTC
The ASCAT instrument on Metop satellites can be used to get measurements of wind speeds of tropical cyclones, such as Super Typhoons.
17 March 2023
02 March 2023
By Vesa Nietosvaara (EUMETSAT) and Hans-Peter Roesli (Switzerland)
Soudelor - 2015
Typhoon Soudelor crossed over the West Pacific and reached its peak intensity on Monday 3 August, becoming the strongest storm of 2015, at that point. While approaching Taiwan, Soudelor still remained a powerful typhoon, with maximum sustained winds near the centre up to 162km/h (Credit: JTWC ).
The Himawari-8 rapid-scanning animation shows the progression of the typhoon between 3–4 August.
Metop ASCAT winds comparison
Figure 2: Himawari-8 rapid scanning with/without Metop ASCAT winds, 6 August 2015 00:35 UTC
Download animation, Himawari-8 rapid scanning, 3 August 00:00 UTC–4 August 23:00 UTC
Download full resolution image, Himawari-8 rapid scanning overlaid with Metop ASCAT Winds, 3 August 00:35 UTC
Download full resolution image, Himawari-8 rapid scanning, 3 August 00:35 UTC
The Metop-B 10.9 IR enhanced image (Figure 3) shows Soudelor over the Western Pacific with the eye of the storm clearly visible. The coldest tops are shown in dark red, indicating storm top temperatures lower than -60°C.
Impacts
Typhoon Soudelor passed directly over Saipan, Northern Mariana Islands, on 2 August, as a Category 2 equivalent storm, with gusts of 146km/h (91mph), causing widespread damage on the island.
In Taiwan at least seven people reportedly died, when the typhoon hit on 6 August, with sustained winds of 161km/h (100mph). At least four million households lost electricity and all 279 domestic flights were canceled on 8 August.
At least 14 people were killed people in eastern China after parts of the country were hit by the heaviest rains in a century.
Nuri - 2014
Typhoon Nuri formed in the western Pacific Ocean on 30 October, then increased in intensity over the following weekend.
It became the equivalent of category 5 in 24 hours, with maximum sustained winds of 290km/h (180mph), tying with Super Typhoon Vongfong as the strongest storm of 2014.
The imagery shows the typhoon as seen by the Metop-B satellite on 4 November, when the storm was directly south of Japan and beginning to slightly weaken.
The first image shows the winds from the ASCAT instrument overlaid on the infrared image. The area of hurricane force winds (red) and a well-developed eye structure can be clearly seen.
The second image is the IR10.8 channel from the AVHRR instrument, the coldest clouds are shown in dark red (190K/-85°C).
Rammasun - 2014
Just prior to making landfall in the Philippines, Rammasun (known locally as Glenda) was a category 3 storm, with sustained winds of 205km/h (127mph). 370,000 people were evacuated before it made landfall, but at least 94 people were reported to have died as it crossed the country on 15 and 16 July. Transport and utility services were bady hit, with 400 flights being grounded at Manila arport.
The infrared image from 15 July 01:00 UTC shows the most active areas of the storm. The colours indicate the cloud top temperatures and red indicates areas where the temperatures are colder than -70°C.
The Natural Colour RGB image shows the clouds overlaid with wind information from the ASCAT instrument on Metop. These show the average winds without gusts.
The ASCAT instrument becomes less sensitive above 110km/h or 60kt, the speed of the maximum winds shown in the centre of the storm.
As typhoon continued to track to the north-west over the Philippines, it lost some of its energy. The images from 16 July 01:00 UTC show the storm did not have a well-defined centre at this stage.
As Rammasun crossed the China Sea on 17 July it re-intensified into a Super Typhoon (maximum sustained winds of 240km/h). Both the Natural Colour RGB and the infrared images taken near the island of Hainan on 18 July show a clear eye structure, measuring around 35km wide. This was because Metop was flying almost vertically over it at the time.
Rammasun was the strongest typhoon to hit southern China in four decades, leaving at least 46 people dead and affecting thousands more.
In the zoomed Natural Colour RGB image the western eye wall is completely exposed and some cumulus clouds can be seen littering the eye.
This animation from the IR 12.0 channel of Fengyun-2E (the Chinese satellite) shows the second part of the lifecyle of Rammasun from 12 July 00:001 UTC to 19 July 11:32 UTC.
Features shown include:
- Transition to a tropical storm on day 14, marked by the onset of counter-clockwise rotation of the high clouds.
- Ploughing through the Philippines and subsequent decay back to a tropical storm on day 15.
- Day 17, rapid re-growth to a typhoon and then a super typhoon, with cloud rotation faster than on day 14.
- Subsequent curving around the northeast corner of the island of Hainan and cutting through the Leizhou peninsula on day 18.
- Landfall of the eye over the coast of the Chinese Guangxi province, still on day 18.
- Rapid dissolution near the Chinese-Vietnamese border on day 19.
Neoguri - 2014
The system became a typhoon, the Western Pacific equivalent of a Atlantic hurricane, on 4 July and intensified to Super Typhoon strength, maximum sustained winds of 240km/h, on 6 July.
The enhanced infrared Metop-B image shows the structure of the storm with a very well defined eye. The colours indicate temperature, with red showing areas where the cloud tops are colder than -70C. The well-defined eye can also be clearly seen on the Metop-B Natural colour RGB. The cyan colour denotes ice cloud. View the KMZ file of Natural Colour RGB in Google Earth.
The Metop-B AVHRR with ASCAT wind overlay, was captured on 06 July, 01:20 UTC, when Neoguri as a category-4 storm situated east of the northern tip of the Philippines. The strongest ASCAT winds, over 144km/h, were found north east of the eye.
On 8 July Metop-A saw Neoguri as it crossed the Japanese island of Okinawa.
Additional content
Meteosat and MTSAT image of Typhoon Nuri, 3 November 09:00 UTC (Flickr)
Super Typhoon Nuri: One of 2014's Most Powerful in Western Pacific Begins to Weaken (The Weather Channel)
Super Typhoon Nuri on track to be strongest storm of 2014 (Washington Post)
Typhoon Nuri warning (Joint Typhoon Warning Center)
Himawari-8 Visible Rapid Scan, 2 Aug 23:15Z–3 Aug 07:17Z (RAM)
Typhoon Soudelor kills at least 21 in China and Taiwan (CNN)
Super Typhoon Soudelor strongest storm on Earth this year (The Telegraph)
Taiwan braced for Typhoon Soudelor (Liam Dutton C4 blog)
MSTAT and Meteosat-7 animation of the typhoon (YouTube)
Typhoon Warning from the Joint Typhoon Warning Center (JTWC)
Rammasun makes landfall in southern China (CIMSS Satellite Blog)
Typhoon Rammasun kills 18 in China (The Guardian)
Super Typhoon Rammasun Moving Over Northern Hainan (Accuweather)
NASA sees Typhoon Rammasun's eye staring at Visayas, Philippines (Phys Org)
NASA's TRMM Satellite Adds Up Typhoon Rammasun's Philippines Deluge
Manila braces for storm surge as Typhoon Rammasun crosses the Philippines (CNN)
Typhoon Rammasun Reaches the Philippines (Weather.com)
65 km wide eye of Super Typhoon Neoguri seen from ISS (Photo Credit: Alexander Gerst/Twitter)
Super Typhoon Neoguri warning (Joint Typhoon Warning Center)
Typhoon Neoguri Batters Okinawa, Japan (Weather.com)
Side profile of Typhoon Neoguri (NASA Earth Observatory)
Typhoon Neoguri (2014) (Wikipedia)
