Key Factors Modulating the Threat of the Arabian Sea's Tropical Cyclones to the Gulf Countries

Abstract

The Arabian Sea is a body of water located in the northwestern Indian Ocean. It extends to about 25°N and from the shores of Somalia on the western side, to the Arabian Peninsula (AP), Iran and Pakistan on the northwestern and northern sides, and western India on the eastern side (Qasim, 1982). The atmospheric circulation here is dominated by the Asian monsoon system, with prevailing low-level southwesterly winds in the summer season and northeasterly winds in the winter months (Schott et al., 2009). Tropical cyclone (hereafter TC) formation is unfavorable in July and August due to the (a) presence of substantial vertical wind shear, when the strong low-level southwesterly winds co-occur with upper-level easterlies associated with the Asian summer monsoon anticyclone (Basha et al., 2020), and (b) copious amounts of precipitation that lower the sea surface temperatures (SSTs) through local air-sea interactions (Fu et al., 2002). Hence, TCs typically form in the pre-monsoon (May and June) or post-monsoon (October and November) months, with an average of one storm per season (Al-Maskari, 2012;Gray, 1968). Cooler SSTs, prevailing anticyclonic relative vorticity, and higher vertical wind shear arising from the presence of the subtropical jet at upper-levels prevent storms from developing in the winter months (Evan & Camargo, 2011). The main trigger of TC formation in the northern Indian Ocean is the Madden-Julian Oscillation (MJO; Madden & Julian, 1994), which is the dominant mode of tropical intraseasonal (30-90 days) variability. The MJO is characterized by regions of enhanced/suppressed convection that propagate eastwards across the tropics, with a poleward component in the boreal summer season (Kawamura et al., 1996). Krishnamohan et al. (2012) reported that roughly 82% of the TCs which formed in the area from 1979 to 2008 occurred during active phase of the MJO. There is also considerable interannual variability, with the higher SSTs and a more favorable dynamic and thermodynamic forcing in Central Pacific El Nino and Southern Oscillation (ENSO; Ashok & Yamagata, 2009) as opposed to eastern Pacific El Nino Southern Oscillation (ENSO) events, leading to an increased likelihood of TC formation in the Arabian Sea (Sumesh & Ramesh Kumar, 2013). The recent increase in SSTs in the basin in conjunction with the Pacific Decadal Oscillation (Mantua & Hare, 2002) also contributes to more active TC seasons (Rajeevan et al., 2013).While TCs are regularly seen in the Arabian Sea, it is rare for them to move into the Sea of Oman, a small body of water that borders Oman, the United Arab Emirates (UAE), Iran and western Pakistan. Only two such occurrences have been reported since 1900 (Mahmoud, 2021): TC Gonu in 2007 which, as of 2021, is the strongest TC

On magnitudes of rapid intensification and destruction of tropical cyclones over the North Indian Ocean

“…Compared to TP1, the moisture content increases to 0.4 gÁkg −1 with an average of 0.2 gÁkg −1 in TP2 (Figure 8c). Several previous basin-wise or season-wise studies also show increased SST, OHC and SH (Deshpande et al, 2021;Francis et al, 2022;Roxy et al, 2020;Tiwari et al, 2022). The increase in SST, OHC and SH enhances the potential, latent and internal energy, hence moist static energy in the atmosphere (Marquet, 2014).…”

Exploring GIS Techniques in Sea Level Change Studies: A Comprehensive Review

“…Sandstorms and dust storms are also frequent. Francis et al [66] showed that there is a correlation between temperature rise and the recurrence of cyclones in the Arabian Peninsula. Because of the growing importance of these events in this area, it is important to focus on them, as the literature on this subject is limited.…”