Government of Sultanate of Oman

Public Authority of Civil Aviation

Directorate General of Meteorology

National Report

To

Panel on Tropical Cyclones in the Bay of Bengal

And

Arabian Sea

43rd Session, India

2-6 May 2016

Directorate General of Meteorology

Public Authority for Civil Aviation

Muscat, Sultanate of Oman

Salalah winter (1986 – 2009)

Muscat during Winter ( 1985 – 2009) Highest wind is 16.1m/s on 26Jan1999

Salalah (1986 – 2009)

The highest wind is southeasterly 17.6m/s on 10May 2002 The average speed is 3.0m/s

First Transitional

The predominant direction is north easterly and highest wind is 15.1m/s from south westerly on 21April1997.The average speed is 2.6m/s

Muscat (1985 – 2009)

Summer

Salalah (1986 – 2009)

Muscat (1985 – 2009)

Salalah Wind Rose (1986 – 2009)

Second Transitional

Muscat Wind Rose (1985 – 2009)

Salalah Wind Rose (1986 – 2009) Muscat Wind Rose (1985 – 2009)

Mean monthly rainfall

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Month

Rain

fall

in

mm Muscat

Salalah

Masirah

Sohar

Khasab

Rainfall in Salalah is mainly in the Summer monsoon but Muscat rainfall is not in Summer months.

Yearly Rainfall

0

50

100

150

200

250

300

350

400

450

500

550

1938 1944 1950 1956 1962 1968 1974 1980 1986 1992 1998 2004 2010

Years

Ra

infa

ll in

mm Salaah

Muscat

Masirah

Sohar

Khasab

Highest recorded rainfall in 1963 at Salalah

Salalah data is available since 1943

Track of Arab 01 and Gonu

• Tropical cyclone Arab01 crossed the coast near Salalah on 10th may 2002 and the Super cyclone Gonu touched the coast at Muscat on 6th June2007.

• Meso scale model MM5 is used to simulate Surface features (track, max. wind and min.

pressure) of the two cases of Cyclone.

• Wave characterists along the coast of Salalah and Muscat during the two cyclone cases are simulated using SWAN model.

Observed Hs = 4.5 m. and computed Hs = 4.8m.

Significant wave height (m)

the significant wave height decreases from more than 12m in deep water to less than 2m near shore. area off southeastern of Muscat coast is characterized by a steeper gradient than that off the northeastern part of Muscat coast. The sheltering effect of Muscat Island is evident.

Location of the points at which significant wave heights was computed along the contour depth 10 m

the south eastern parts of Muscat coast are more affected by higher waves (6m-8m) than that north western parts of the coast (4m-6m).

Hs off the seaward side of Muscat islands is considerably higher than off the shoreward side of the island (at point 13 Hs 3.5m ,while at point 14 Hs 8m).The minimum computed wave height of about 1.5 m occurred inside Sultan

Qabous

Harbor.

observed: Hs = 5 to 7.5 m and computed by SWAN Hs = 6.1 m.

Computed energy dissipation J/m2/s from a stationary SWAN run on June 6, 2007

The near shore area off the southeastern coast of Muscat is characterized by higher energy dissipation due to bottom friction and wave breaking.

Tracks of the tropical cyclones over the Arabian Sea which Oman in first transitional period since 1948 till now ( the tracks are based on data taken from http://weather.unisys.com).

Tracks of the tropical cyclones over the Arabian Sea which affected Oman in second transitional period since 1948

Observed Tracks of tropical cyclones (upto 2010)which reach Oman Coast

Annual Report on Activities in Meteorology

In the Sultanate of Oman

During the year 2015

1. Meteorological Events

1.1 Tropical Storm ASHOBAA ( 5-12 June 2015):

In the pre monsoon season, Tropical Storm ‘ASHOBAA’ developed over Arabian Sea on the 5th June 2015, its center was about 1400 km away from the Oman coast. `ter was between 64–74 km/h (35–40 kts) and the movement became more west to north westward. On 9th June the tropical storm moved closer to Oman — approximately 500 km off the coast. At that time high and medium level clouds touched Oman coast and the sea condition became rough gradually with maximum wave height reached of 3.5 m. Oman’s forecasting Center issued a series of reports and advisories to alert the public about the system.

Fig.1 Metop-A Visible with ASCAT winds overlaid, 10 June 05:18

UTC

On 11th of June, the storm ‘ASHOBAA’ weakened into a deep depression and further next day its weakened into a depression and into a well-marked low pressure area near southeastern coasts of Oman. Moderate to heavy rains were reported from the tropical storm ‘ASHOBAA’.

Fig.3 Track of CS ASHOBAA

By 10th of June, while the tropical storm was moving west to

southwestward toward Oman coasts it’s started to weaken

slightly due to high vertical wind shear, low ocean thermal

energy and a colder oceanic region. In addition, the satellite

images showed clearly a dry air being ingested into the

system. Also, an area of low-level dust northeast of the

system can be clearly seen on the Meteosat-10 Dust and

Natural Colour RGB images (Figure 2). The dust which is

originated over Iran and Afghanistan is visible over Sea of

Oman. Fig.2 Meteosat-10 Dust RGB, 10 June 02:00 UTC

Fig.4 Total precipitation 11-13 June 2015

1.2. Tropical Cyclone Chapala 28 Oct-04 Nov 2015

1.2.1. Tropical Cyclone Chapala:

Tropical Cyclone Chapala formed from a low pressure area over southeast Arabian Sea which intensified into a depression on 28th October. It moved north-northwestwards and intensified into a cyclonic storm on 29th over east central Arabian Sea and later same day it’s intensified into a tropical cyclone. It then moved mainly westwards, maintained its intensity until 1st of November and then started weakening gradually.

In the post monsoon season they were two tropical cyclones formed over Arabian Sea:

Figure 5: Metosat-10 Tropical Airmass, 2 Nov 07:00 UTC

Tropical cyclone Chapala continued moving west to northwestwards and crossed Yemen coasts with wind speed of 65 knots (120 kmph) on 3rd of November as Tropical cyclonic storm. And moved further westwards and weakened into a cyclonic storm and then into deep depression. On 4th November it became a depression and then laid as well marked low pressure area over Yemen. Heavy thundershowers with strong winds were reported with floods at many Yemeni weather stations. Oman’s Met issued a series of bulletins and alerts about ‘Chapala’ some of them sent to Yemen Met Office.

Figure 7: Precipitation with Maximum gust speed Figure 6: Track of Tropical Cyclone Chapala

1.2.2. Cyclonic Storm, Megh 05-10 November 2015 After a week of formation of tropical cyclone ‘Chapala’. Another tropical system ‘depression’ formed over the east central of Arabian Sea on 5th November. It moved west-southwestwards and intensified into a cyclonic storm .On the 7th of November it intensified into tropical cyclone ‘Megh’ . By 9th November Megh started weakening rapidly into deep depression and recurved northeastwards on the 10th November and crossed the Yemeni coast as a Deep depression.

Figure 8: Track of Tropical Cyclone Megh

2. Meteorological Facilities 2.1 Upper Air Observation:

The Sultanate of Oman operates two upper air-observing stations located at Muscat (41256) and Salalah (41316). Both these are equipped with Vaisala’s Digicora GPS wind finding system. The radiosonde used is Vaisala RS 41 equipment. One flight is launched from each of these stations in a day.

2.2 Ship Weather Reports:

Weather Reports from Ships are received through GTS as well as from Muscat Coastal Radio Station. In addition Ship reports are also received from the Royal Oman Navy.

.

Synoptic Land Stations:

There are a total of 64 meteorological stations out of which 23 are listed in the WMO’s Regional Basic Synoptic Network (RBSN) including 2 radiosonde stations, 12 Regional Basic Climatological Network (RBCN) stations out of which 3 listed in Global Climate Observing System Surface Network. Additional 9 Automatic Weather Stations will be installed during this year.

Weather Radar (5)

Network of coastal Tide gauges for sea level measurement (10)

Wave Radar network and coverage (5)

• There are 5 wave radar stations where installed for detecting ocean current and tsunami wave.

• 4 covering Oman sea • 1 for Arabian sea. • In future: Planning to install new radars to cover rest of Arabian sea coasts

3.Training/Research :

The 7th WMO Center of Excellence in Oman has conducted the 11th session of satellite application

Workshop/Seminar/Training/Research Course Country No. of

Persons

PhD. In Dust Modelling Australia 1

EUMETSAT Satellite Application Course Oman 15

Climatological database CLDB Slovakia 1

Aeronautical Meteorological Forecasting China 2

Tropical cyclone Forecasting Course India 2

Marine Forecasting South Africa 2

Tsunami Germany 6

Observer Training India 18

Training in McIDAS-V Oman 7

Weather Radar Oman 8

Basics in linux Oman 5