Microwave warm core of Tropical Cyclone Mekunu

Microwave warm core of Tropical Cyclone Mekunu

22 May 2018–26 May

Microwave warm core of Tropical Cyclone Mekunu
Microwave warm core of Tropical Cyclone Mekunu

Tropical Cyclone Mekunu was a Category 3 tropical cyclone that made landfall near Salalah, Oman on 26 May 2018.

Last Updated

10 November 2020

Published on

22 May 2018

By Sreerekha Thonipparambil (EUMETSAT)

Tropical cyclone Mekunu developed as a low pressure over North Indian Ocean on 21 May 2018, reached its peak intensity on 25 May, before making a landfall near Salalah, Oman on the 26 May.

 Meteoat-11 Airmass RGB, 23 May 17:15 UTC
Figure 1: Meteoat-11 Airmass RGB, 23 May 17:15 UTC

Mekunu had 1-minute sustained winds estimated at 115 mph and produced about 280 mm rainfall in 24 hours — more than three times the annual rainfall average in the region. The storm and the resulting flooding caused destruction including casualties in Oman and Yemen.

The capability of satellite microwave observations to measure the warm core of tropical cyclones is presented in this case study. Unlike visible and infrared channels, channels of microwave sounding instruments like AMSU, onboard Metop and NOAA satellites, can be used to analyse the vertical structure of warm core.

For Mekunu, this is demonstrated in the warm brightness temperature anomalies in Channels 7 (54.94 GHz) and 8 (55.54 GHz) of AMSU. These channels peak at altitudes which are not affected by clouds, around 200 hPa and 100 hPa respectively. The warm brightness temperature anomalies increase as the cyclone intensifies. The series of images below depicts this behaviour as the storm develops, intensifies and dissipates. Images courtesy of the CIMSS Tropical Cyclones website .

For very strong storms the warm anomalies can be seen in channels 6 (54.4 GHz) and 5 (53.596 GHz) too (peaking at around 350 hPa and 550hPa, respectively). The direct correlation of AMSU brightness temperature anomalies with both wind speed and minimum sea level pressure can be used to estimate the intensity of the Tropical Cyclone.

Channel 8

Metop-B AMSU-A Channel 8 Brightness Temperature, 22 May 17:33 UTC. Credit: CIMSS
Figure 1: Metop-B AMSU-A Channel 8 Brightness Temperature, 22 May 17:33 UTC. Credit: CIMSS
NOAA-18 AMSU-A Channel 8 Brightness Temperature, 23 May 16:00 UTC. Credit: CIMSS
Figure 2: NOAA-18 AMSU-A Channel 8 Brightness Temperature, 23 May 16:00 UTC. Credit: CIMSS
NOAA-18 AMSU-A Channel 8 Brightness Temperature, 24 May 15:49 UTC. Credit: CIMSS
Figure 3: NOAA-18 AMSU-A Channel 8 Brightness Temperature, 24 May 15:49 UTC. Credit: CIMSS
NOAA-18 AMSU-A Channel 8 Brightness Temperature, 25 May 15:39 UTC. Credit: CIMSS
Figure 4: NOAA-18 AMSU-A Channel 8 Brightness Temperature, 25 May 15:39 UTC. Credit: CIMSS
Metop-B AMSU-A Channel 8 Brightness Temperature, 24 May 17:52 UTC. Credit: CIMSS
Figure 5: Metop-B AMSU-A Channel 8 Brightness Temperature, 24 May 17:52 UTC. Credit: CIMSS

Channel 7

Metop-B AMSU-A Channel 7 Brightness Temperature, 22 May 17:33 UTC. Credit: CIMSS
Figure 6: Metop-B AMSU-A Channel 7 Brightness Temperature, 22 May 17:33 UTC. Credit: CIMSS
NOAA-18 AMSU-A Channel 7 Brightness Temperature, 23 May 16:00 UTC. Credit: CIMSS
Figure 7: NOAA-18 AMSU-A Channel 7 Brightness Temperature, 23 May 16:00 UTC. Credit: CIMSS
NOAA-18 AMSU-A Channel 7 Brightness Temperature, 24 May 15:49 UTC. Credit: CIMSS
Figure 8: NOAA-18 AMSU-A Channel 7 Brightness Temperature, 24 May 15:49 UTC. Credit: CIMSS
NOAA-18 AMSU-A Channel 7 Brightness Temperature, 25 May 15:39 UTC. Credit: CIMSS
Figure 9: NOAA-18 AMSU-A Channel 7 Brightness Temperature, 25 May 15:39 UTC. Credit: CIMSS
Metop-B AMSU-A Channel 7 Brightness Temperature, 24 May 17:52 UTC. Credit: CIMSS
Figure 10: Metop-B AMSU-A Channel 7 Brightness Temperature, 24 May 17:52 UTC. Credit: CIMSS

Channel 6

Metop-B AMSU-A Channel 6 Brightness Temperature, 22 May 17:33 UTC. Credit: CIMSS
Figure 11: Metop-B AMSU-A Channel 6 Brightness Temperature, 22 May 17:33 UTC. Credit: CIMSS
NOAA-18 AMSU-A Channel 6 Brightness Temperature, 23 May 16:00 UTC. Credit: CIMSS
Figure 12: NOAA-18 AMSU-A Channel 6 Brightness Temperature, 23 May 16:00 UTC. Credit: CIMSS
NOAA-18 AMSU-A Channel 6 Brightness Temperature, 24 May 15:49 UTC. Credit: CIMSS
Figure 13: NOAA-18 AMSU-A Channel 6 Brightness Temperature, 24 May 15:49 UTC. Credit: CIMSS
NOAA-18 AMSU-A Channel 6 Brightness Temperature, 25 May 15:39 UTC. Credit: CIMSS
Figure 14: NOAA-18 AMSU-A Channel 6 Brightness Temperature, 25 May 15:39 UTC. Credit: CIMSS
Metop-B AMSU-A Channel 6 Brightness Temperature, 24 May 17:52 UTC. Credit: CIMSS
Figure 15: Metop-B AMSU-A Channel 6 Brightness Temperature, 24 May 17:52 UTC. Credit: CIMSS

AMSU-A Brightness Temperature Anomaly

Metop-B AMSU-A Brightness Temperature Anomaly, 22 May 17:33 UTC. Credit: CIMSS
Figure 16: Metop-B AMSU-A Brightness Temperature Anomaly, 22 May 17:33 UTC. Credit: CIMSS
NOAA-18 AMSU-A Brightness Temperature Anomaly, 23 May 16:00 UTC. Credit: CIMSS
Figure 17: NOAA-18 AMSU-A Brightness Temperature Anomaly, 23 May 16:00 UTC. Credit: CIMSS
NOAA-18 AMSU-A Brightness Temperature Anomaly, 24 May 15:49 UTC. Credit: CIMSS
Figure 18: NOAA-18 AMSU-A Brightness Temperature Anomaly, 24 May 15:49 UTC. Credit: CIMSS
NOAA-18 AMSU-A Brightness Temperature Anomaly, 25 May 15:39 UTC. Credit: CIMSS
Figure 19: NOAA-18 AMSU-A Brightness Temperature Anomaly, 25 May 15:39 UTC. Credit: CIMSS
Metop-B AMSU-A Brightness Temperature Anomaly, 24 May 17:52 UTC. Credit: CIMSS
Figure 20: Metop-B AMSU-A Brightness Temperature Anomaly, 24 May 17:52 UTC. Credit: CIMSS

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