3D Structure of the Ras Al Hadd Oceanic Dipole

In the Arabian Sea, southeast of peninsula, an oceanic dipole, named Ras Al Hadd (RAH) is formed each year, lying near cape. The RAH dipole association a cyclonic eddy (CE) to northeast, with anticyclonic (AE) southwest. This intensifies in summer monsoon and disappears during winter monsoon. has been described previously, but mostly for its surface expression, short time intervals. Here, we describe 3D structure this over 2000–2015 period, by combining colocalized ARGO float profiler data (a total 7552 profiles inside outside dipole) angular momentum detection tracking algorithm (AMEDA) data. We show first different water masses dipole. presence Persian Gulf (PGW) below 200 m depth confirmed both eddies. Sea high salinity (ASHSW) found exclusively AE; layer fresh cold observed above 100 By analyzing potential density structures, that CE surface-intensified while AE subsurface-intensified. sea level anomaly shows 0.04 elevation 0.2 depression CE. faster geostrophic velocity, (vertical respectively) 0.6 s−1 than AE, 0.15 (respectively, 3 day−1 AE). After presenting vertical dominance nonlinear Ekman pumping linear affecting As consequence, explain CE’s longer lifetime intensity shallowness, sensitivity interaction atmosphere (in particular wind stress) neighboring examined possible (co)existence symmetric, barotropic, baroclinic instabilities These coexist They are intensified CE, which suggests unstable rather stable or may need long be unstable.