**4. Discussion**

Our study has sought to support the management of risk from natural hazard in Oman, through developing an improved understanding of TC hazard. To do this we have: collated geographical data from the Indian Metrological Department for all known TC and cyclonic storm events in the Arabian Sea since 1881; plotted the tracks of each storm from point of origin to expiration, by storm category (size), by month and season, and with particular reference to those events that made landfall in Oman (these events tend to be large); and conducted a directional analysis to determine likely course of a TC and a spatial (KDE) analysis to determine geographic areas at higher risk of TC makings landfall.

Our analysis sheds light on the origins and tracks of Arabian Sea TCs by season. TCs in the Arabian Sea form in two seasons: the pre-monsoon and the postmonsoon [30, 31]; our analysis reveals a distinct difference in the subsequent TC track between these pre-and post-monsoon periods. All pre-monsoon TCs form in the Arabian Sea itself. In May, they start in the south-east and track to the southwest; in June their origin moves north-east and TCs track north-west; in July TCs form further north still, but continue to track north-west. There are however cases in June when TCs curve north-east toward India. TCs in the post-monsoon period originate over a larger area extending as far as the Bay of Bengal, with TCs tracking west over India to arrive in the Arabian Sea. However, most TCS in this season form in the north-east Arabian Sea in September, then south-east and the south Arabian Sea from October – December. TCs tend to track south-west toward the Gulf of Aden and the Horn of Africa in October–December, although some TCs in the east Arabian Sea recurved to India.

In general, TCs affect Omani coastal areas from Muscat in the north to Salalah in the south (**Figure 6**). Our analysis specifically of those TCs that made landfall in Oman shows that the origins and tracks for systems that make landfall in Oman also vary by season and month of formation. Pre-monsoon TCs tend to originate in the south of the region in May and frequently make landfall between Masirah Island (central Oman) and Salalah in south-west Oman. In June TCs tend to originate further north and make landfall between Masirah Island and Ras Al Had, the easterly most point of Oman at the mouth of the Oman Sea. There are however, some exceptions to this general behavior. Post-monsoon cyclones also have distinct origins and tracks. September TCs tend to form in the north and are likely to make landfall in central Oman, from Masirah Island to Ras Madrakah (Al Duqum), whilst from October–December TCs move progressively toward Salalah in south-east Oman.

northern region, and indeed this is what happened, with the storm traveling to the north-eastern coast, hitting Oman near Ras-Al Had. Similarly, TC Mukuno that also developed in the pre-monsoon (May 2018), traveled to the south-eastern coast, hitting Salalah and Yemen, as suggested by our analysis. For the post-monsoon we note that TC Hika, which formed in September 2019, traveled to the mid-Omani coastline toward Al Duqum (where it caused substantial damage), whilst TC Luban, formed in the Arabian Sea in October 2018, took a direction to the south-west Arabian Sea toward Salalah and Yemen. Whilst such observations cannot qualify as a formal test of the analysis, they do provide support for the general conclusions as

*Arabian Sea Tropical Cyclones: A Spatio-Temporal Analysis in Support of Natural Hazard…*

*DOI: http://dx.doi.org/10.5772/intechopen.96961*

Thus our analysis reveals a series of general and broadly predictable spatiotemporal patterns. Individual events may deviate from these trends, but the general patterns are useful in informing natural hazard risk assessment and management in the region, including Oman, which has suffered extensive damage in the past due to TCs. The results could, for example, assist with more targeted cyclone preparation

to the seasonal behavior of cyclone tracks in the region.

**Figure 6.**

**155**

*Oman's coastal areas.*

Our tracks analysis (part of a wider study of TC resilience in Oman) was first conducted up to and including 2014, and subsequent events have provided an opportunity to test our general conclusions. Early confirmation came from tropical storm Ashobaa in June 2015, which our results suggested would strike Oman in the *Arabian Sea Tropical Cyclones: A Spatio-Temporal Analysis in Support of Natural Hazard… DOI: http://dx.doi.org/10.5772/intechopen.96961*

Storms in May track toward the mid-east coast of Oman and Ras Madrakah. In June storms have a similar LDM but move to the north-west Arabian Sea and toward Oman's capital, Muscat, as they originate further north and east than May storms, whilst having a track length several hundred kilometers greater. A similar situation occurs in the post-monsoon. The LDM of tracks is similar for September and October storms, with October storms originating to the northeast of May storms. September storms thus tend to track toward Masirah Island on Oman's eastern coast, whilst in October, storms making landfall tend to head toward the south-east

Our study has sought to support the management of risk from natural hazard in Oman, through developing an improved understanding of TC hazard. To do this we have: collated geographical data from the Indian Metrological Department for all known TC and cyclonic storm events in the Arabian Sea since 1881; plotted the tracks of each storm from point of origin to expiration, by storm category (size), by month and season, and with particular reference to those events that made landfall in Oman (these events tend to be large); and conducted a directional analysis to determine likely course of a TC and a spatial (KDE) analysis to determine geo-

Our analysis sheds light on the origins and tracks of Arabian Sea TCs by season.

In general, TCs affect Omani coastal areas from Muscat in the north to Salalah in the south (**Figure 6**). Our analysis specifically of those TCs that made landfall in Oman shows that the origins and tracks for systems that make landfall in Oman also vary by season and month of formation. Pre-monsoon TCs tend to originate in the south of the region in May and frequently make landfall between Masirah Island (central Oman) and Salalah in south-west Oman. In June TCs tend to originate further north and make landfall between Masirah Island and Ras Al Had, the easterly most point of Oman at the mouth of the Oman Sea. There are however, some exceptions to this general behavior. Post-monsoon cyclones also have distinct origins and tracks. September TCs tend to form in the north and are likely to make landfall in central Oman, from Masirah Island to Ras Madrakah (Al Duqum), whilst from October–December TCs move progressively toward Salalah in south-east

Our tracks analysis (part of a wider study of TC resilience in Oman) was first conducted up to and including 2014, and subsequent events have provided an opportunity to test our general conclusions. Early confirmation came from tropical storm Ashobaa in June 2015, which our results suggested would strike Oman in the

TCs in the Arabian Sea form in two seasons: the pre-monsoon and the postmonsoon [30, 31]; our analysis reveals a distinct difference in the subsequent TC track between these pre-and post-monsoon periods. All pre-monsoon TCs form in the Arabian Sea itself. In May, they start in the south-east and track to the southwest; in June their origin moves north-east and TCs track north-west; in July TCs form further north still, but continue to track north-west. There are however cases in June when TCs curve north-east toward India. TCs in the post-monsoon period originate over a larger area extending as far as the Bay of Bengal, with TCs tracking west over India to arrive in the Arabian Sea. However, most TCS in this season form in the north-east Arabian Sea in September, then south-east and the south Arabian Sea from October – December. TCs tend to track south-west toward the Gulf of Aden and the Horn of Africa in October–December, although some TCs in the east

coast, and Salalah, Oman's main southern city.

graphic areas at higher risk of TC makings landfall.

Arabian Sea recurved to India.

Oman.

**154**

**4. Discussion**

*Agrometeorology*

northern region, and indeed this is what happened, with the storm traveling to the north-eastern coast, hitting Oman near Ras-Al Had. Similarly, TC Mukuno that also developed in the pre-monsoon (May 2018), traveled to the south-eastern coast, hitting Salalah and Yemen, as suggested by our analysis. For the post-monsoon we note that TC Hika, which formed in September 2019, traveled to the mid-Omani coastline toward Al Duqum (where it caused substantial damage), whilst TC Luban, formed in the Arabian Sea in October 2018, took a direction to the south-west Arabian Sea toward Salalah and Yemen. Whilst such observations cannot qualify as a formal test of the analysis, they do provide support for the general conclusions as to the seasonal behavior of cyclone tracks in the region.

Thus our analysis reveals a series of general and broadly predictable spatiotemporal patterns. Individual events may deviate from these trends, but the general patterns are useful in informing natural hazard risk assessment and management in the region, including Oman, which has suffered extensive damage in the past due to TCs. The results could, for example, assist with more targeted cyclone preparation

and deployment of emergency response resources, based upon areas most at risk to cyclones overall (strategic planning), and to specific storm events when these are first identified (tactical planning). For example, knowing that cyclones that develop in June are more likely to make landfall in Oman's northern part is valuable emergency planning intelligence.

Globally, the urban area exposed to both flood and drought is forecast to at least double from 2000–2030 [32], indicating the growing importance of understanding and managing these risks. For Oman, the key risk is loss of life and damage from TC. Developing an improved understanding of TC occurrence and behavior, through historical analysis of TC timing and tracks should help to build resilience to TC, and climate change, for the country. Building resilience to TC requires a much wider process of institutional organization and action, which we discuss elsewhere [33] with specific reference to Oman's natural hazard management governance. However, a key element of natural hazard risk management is an understanding of the hazard itself. Our historical analysis of nearly a century and a half of TC tracks in the Arabian Sea, provides enhanced insight into the likely timing and location of TCs making landfall in Oman. This knowledge can support strategic decision making (e.g. prior appraisal of potential flood damage; location prioritization of mitigation resources) and improved understanding of likely destination of TC when they emerge in the Arabian Sea, thus supporting pre-emptive event management.
