Weather radar and ancillary observations of the convective system causing the northern Persian Gulf meteotsunami on 19 March 2017

Abstract

This study documents the atmospheric system driving the observed meteotsunami waves that hit the northern Persian Gulf on 19 March 2017 during high tide. This destructive meteotsunami event resulted in coastal inundations that reached several hundred metres inland along the 100-km coastline between the cities of Dayyer and Asaluyeh and caused the death or injury of 27 persons. Based on previously published research, eyewitness reports, oceanic and atmospheric observations, including synoptic station and weather radar data, and available reanalysis ERA5 products, this study provides new insights into destructive events, particularly mesoscale atmospheric systems conjoined with observed meteotsunami waves. Precipitation intensity, maximum reflectivity and echo top height images provided by the weather radar covering the affected area and the area over which the meteotsunamigenic disturbance travelled revealed that a strong convective system that encompassed the mid-and upper troposphere entered the northern Persian Gulf approximately 4 h before the event and moved eastward. Two hours before reaching the affected coastline, this convective system was reshaped to an elongated and narrow squall line varying between 70 and 130 km in length with a width of less than 10 km and travelled at an average speed of approximately 24 m/s over the sea. The peak maximum reflectivity of the squall line always surpassed 40 dBZ, while it increased to 60 dBZ near the Dayyer area. As such, intense atmospheric disturbances are known to be associated with sharp air pressure increases, and these disturbances were found to resonantly pump energy to the ocean through Proudman resonance for over 12 or more disturbance wavelengths (i.e. up to 120 km in this study). A half-metre meteotsunami wave was presumably created in the open sea and then amplified while travelling towards the shore where it broke as a meteotsunami bore and inundated the coastal areas. Further research on the physical mechanisms driving the interactions between meteotsunamigenic disturbances and ocean responses, the recurrence of such events and meteotsunami hazard assessments along the affected coastline is envisaged.

The Skill Assessment of Weather and Research Forecasting and WAVEWATCH-III Models During Recent Meteotsunami Event in the Persian Gulf

“…Heidarzadeh et al (2020) studied this meteorological event using satellite imageries, atmospheric reanalysis products, and in situ measurements, including sea level data and highresolution air pressure data along the southern Persian Gulf. The rainfall intensity, maximum reflection, and echo top height images provided by the weather radar confirmed that a strong convergent system, including the middle and upper troposphere, had entered the northern Persian Gulf approximately 4 h before the event and moved to the east (Kazeminezhad et al, 2021). Then, 2 h before its landfall, the convection system deformed into a narrow and long hurricane with 70-130 km length, less than 10 km width, and a transverse speed of 24 m/s.…”

“…In summer, it blows mainly between May and July while in winter, it occurs between December and early March. However, this phenomenon is often not accompanied by coastal floods and generally causes waves between 0.25 to 0.4 meters in the northernmost coastal areas of the Persian Gulf (Thoppil and Hogan, 2010;Kazeminezhad et al, 2021).…”

“…On 19 March 2017, an unexpected ∼3-m-long wave struck the northern shores of the Persian Gulf, and at least five people were killed in the port of Dayyer (see Figure 1 for its location). It also led to extended damages to ships, residential areas, and coastal facilities adjacent to this port (Salaree et al, 2018;Heidarzadeh et al, 2020;Kazeminezhad et al, 2021). Salaree et al (2018) conducted a field study on the damaged coastline and reconstructed the initial picture of the whole event.…”

Special issue on the global perspective on meteotsunami science: editorial

“…Smirnov et al (2021) examined spatial structure of eigenmodes in individual bays of the Peter the Great Gulf located in the Sea of Japan, demonstrating that resonant amplification of arriving waves in these bays can destructively multiply the height of both tsunamis and meteotsunamis. Finally, Kazeminezhad et al (2021) completed the earlier studies of the 2017 Dayyer event (Salaree et al 2018;Heidarzadeh et al 2020) and documented weather radar and ancillary atmospheric observations during the catastrophic meteotsunami in the Persian Gulf that killed 5 people and injured 22, focusing on a narrow and intense squall line that was detected in the radar images throughout its propagation over the sea before hitting the coastline.…”

“…In some bays, the meteotsunami waves have been recorded with heights of several metres and associated currents of several knots, which may pose a particular threat to low-tidal regions, like the Mediterranean and Black seas (Vilibić et al 2021) and the Great Lakes (Bechle et al 2016), where the coastal infrastructure is not adapted to such strong sea-level oscillations. A number of catastrophic meteotsunamis have been recorded in modern times: (1) The Great Lakes, USA, in 1954, killing 7 people in Chicago (Ewing et al 1954), (2) Vela Luka, Croatia, in 1978, resulting in US$7 million in damage at that time (Vučetić et al 2009), (3) Nagasaki Bay, Japan, in 1979, killing 3 people and flooding coastal cities (Hibiya and Kajiura 1982), (4) Ciutadella in the Balearic Islands, Spain, in 1984 and2006, sinking tens of yachts and boats and causing of tens of millions of euros in damage (Jansà and Ramis 2021), (5) Daytona Beach, Florida, USA, in 1992, causing at least 75 injuries and damaging several dozen vehicles on the beach (Churchill et al 1995), (6) the catastrophic 2007 event in Mostaganem (Algeria) responsible for the death of 12 people (Okal 2021), (7) the catastrophic meteotsunamis that affected the north Persian Gulf coastline, Iran, causing the death of 5 people and injuring 22 (Salaree et al 2018;Heidarzadeh et al 2020;Kazeminezhad et al 2021), and several others. Being so destructive, the phenomenon intimidated the inhabitants to such an extent that they gave them particular local names: "abiki" and "yota" in Japan, "rissaga" or "resaca" in Spain, "šćiga" or "štiga" in Croatia, "marrubbio" or "marrobbio" in Sicily, "milghuba" in Malta, "Seebär" in Baltic countries, and more (Monserrat et al 2006;Rabinovich 2009).…”