@article{shi_morrison_bohm_manghnani_2000, title={The Oman upwelling zone during 1993, 1994 and 1995}, volume={47}, ISSN={["0967-0645"]}, DOI={10.1016/S0967-0645(99)00142-3}, abstractNote={Satellite-derived sea-surface temperature, TOPEX/POSEIDON (T/P) sea-level anomalies (SLAs), model wind data, and hydrographic data are used to characterize the upwelling along the Oman coast during the US Joint Global Ocean Flux Study (US JGOFS) Arabian Sea Process Study (ASPS) in 1995 as well as to look at interannual variability in the upwelling over the period 1993–1995. Empirical orthogonal function (EOF) analysis of the satellite-derived sea-surface temperature (SST) at the locations of the US JGOFS standard stations shows the first mode, which represents a biannual variability, contributes 67% of the total variance. In addition, the SST shows the upwelling “front” moving offshore with the development of Southwest (SW) Monsoon in early June 1995, reaching a maximum distance of approximately 120 km by late August 1995. Finally, SST shows the persistence of cold upwelling waters for nearly a month after the end of the SW Monsoon within the bays along the Oman coast. TOPEX/POSEIDON SLAs indicate that with the onset of the SW Monsoon, a 30-cm drop in steric height is observed along the Oman coast associated the presence of the cool upwelled waters. This drop in steric height sets up a horizontal pressure gradient and results in a compensating along-shore, northeastward-flowing, geostrophic current (East Arabian Current; EAC) during the SW Monsoon. Similarly, the altimeter data slow an offshore decrease in steric height during the Northeast (NE) Monsoon, indicating a seasonal reversal in direction of the EAC with flow to the southwest. Subsurface temperature data indicate that the actual uplifting of isotherms associated with the upwelling can be found to a distance of approximately 260 km from the shore and to a depth of 150–200 m. Using along-track altimetry data, we estimate that, for a region 260 km in offshore distance and 600 km alongshore, 2.2×106, 1.4×106 and 0.55×106 m3 s−1 were upwelled through the 100 m level with upwelling velocities O (2.0×10−5 m s−1), during the SW Monsoons of 1993, 1994 and 1995, respectively. The reduced upwelling in the summer of 1995 is attributed to a reduction in wind-stress curl along the Arabian coast when compared to 1993 and 1994.}, number={7-8}, journal={DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY}, author={Shi, W and Morrison, JM and Bohm, E and Manghnani, V}, year={2000}, pages={1227–1247} }
 @article{shi_morrison_bohm_manghnani_1999, title={Remotely sensed features in the US JGOFS Arabian Sea Process Study}, volume={46}, ISSN={["0967-0645"]}, DOI={10.1016/S0967-0645(99)00035-1}, abstractNote={TOPEX/POSEIDON altimeter data and wind data are used to calculate the geostrophic transport and Ekman transport in the northern Arabian Sea within the upper 500 m. In the summer, the upper 500-m layer in the northern Arabian Sea is horizontally divergent, with a transport going out of the northern Arabian Sea across 15.75°N reaching a maximum of 10×106 m3 s−1 in late June. In the winter, it is horizontally convergent, with a transport within the upper 500 m layer across 15.75°N reaching about 5×106 m3 s−1 into the northern Arabian Sea. The mean net transport for 1993–1995 out of the northern Arabian Sea across 15.75°N within the upper 500 m is estimated to be 0.74×106 m3 s−1. Most of the deep water upwelling across the 500 m depth, which compensates for the loss of waters in the upper 500-m layer, occurs in the eastern part of the northern Arabian Sea. The North Equatorial Current is found to deflect into the Arabian Sea during the NE Monsoon and the Spring Intermonsoon periods. In addition, estimates are made of the net transport into and out of the region encompassed by the US Joint Global Ocean Flux Study (JGOFS) Arabian Sea Process Study. The total transport out of the US JGOFS region is approximately 3.5–4.0×106 m3 s−1 in July of 1995 in the upper 500 m. Analysis of the mean sea surface height for the Arabian Sea shows a periodic change with the seasonal monsoon, with a typical depression of the ocean surface during the summer indicative of Arabian Sea cooling. The yearly change of the averaged sea surface height at 15.75°N is of the order of 15 cm. Rossby wave propagation also was observed at 15.75°N in the sea surface height fields.}, number={8-9}, journal={DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY}, author={Shi, W and Morrison, JM and Bohm, E and Manghnani, V}, year={1999}, pages={1551–1575} }
 @article{bohm_morrison_manghnani_kim_flagg_1999, title={The Ras al Hadd Jet: Remotely sensed and acoustic Doppler current profiler observations in 1994-1995}, volume={46}, ISSN={["0967-0645"]}, DOI={10.1016/S0967-0645(99)00034-X}, abstractNote={The existence of a surface barotropic front-jet system at the confluence region off the eastern tip of Oman (Ras Al Hadd or RAH) is documented for 1994–1995 through advanced very high resolution radiometer (AVHRR) and acoustic Doppler current profiler (ADCP) observations. The thermal signature of this confluence is visible in 1995 between early May and the end of October, i.e., throughout the SW Monsoon and into the transition period between SW and NE Monsoons. The thermal characteristics are those of a NE-oriented front between cooler water of southern (upwelled) origin and warmer waters of northern Gulf of Oman origin. During the period when the thermal front is absent, ADCP data suggest that the confluence takes a more southward direction with Gulf of Oman waters passing RAH into the southeastern Oman coastal region. The thermal gradient is initially small (June–July) but later increases (August–October) into a front that exhibits small-scale instabilities. Surface current velocities within the jet, estimated by tracking these features in consecutive satellite images, are 0.5–0.7 m s−1 and in remarkable agreement with concurrent ADCP retrievals in which the seasonal maximum in velocity is 1 m s−1. ADCP observations collected during several US JGOFS cruises reveal a weakly baroclinic current in the confluence region that drives the waters into the offshore system. The fully developed jet describes a large meander that demarcates two counter-rotating eddies (cyclonic to the north and anticyclonic to the south of the jet) of approximately 150–200 km diameter. The southern eddy of this pair is resolved by the seasonally averaged, sea-level anomaly derived from TOPEX/Poseidon observations. During the SW Monsoon, the RAH Jet advects primarily cold waters along its path, but as soon as the wind system reverses with the transition to the intermonsoonal period, a warm current is rapidly established that advects the surface coastal waters of the Gulf of Oman offshore. In accordance with the interannual variation of the wind forcing phase, the reversal of the currents from NE to SW occurred earlier in 1994 than in 1995, confirming that the RAH Jet is integral part of the East Arabian Current. The transport of the Jet, estimated by combining SST information on the width with ADCP data on the velocity's vertical structure, is found to fluctuate between 2–8×106 m3 s−1 and its thickness between 150–400 m. These significant fluctuations are due to the time-variable partition of horizontal transport between eddies and the RAH Jet and are potentially important to the nutrient and phytoplankton budgets of the Arabian Sea.}, number={8-9}, journal={DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY}, author={Bohm, E and Morrison, JM and Manghnani, V and Kim, HS and Flagg, CN}, year={1999}, pages={1531–1549} }
 @article{manghnani_morrison_hopkins_bohm_1998, title={Advection of upwelled waters in the form of plumes off Oman during the Southwest Monsoon}, volume={45}, ISSN={["0967-0645"]}, DOI={10.1016/S0967-0645(98)00062-9}, abstractNote={Advanced Very High Resolution Radiometer (AVHRR) imagery of sea-surface-temperature, TOPEX/POSEIDON measurements of sea-level-anomaly (SLA), and modeled surface winds and wind-stress fields are used in concert with other ancillary data to describe the influence of the 1995 Southwest Monsoon on the distribution of upwelled waters off the coast of Oman. The Oman upwelling zone is characterized by the entrainment of cold upwelled waters into plumes extending from the coast into the deep ocean unaffected by the steep bottom gradients. The most prominent of these plumes is found offshore of Ras al Madraka. A mechanism for the entrainment of upwelled water into plumes is hypothesized, and validated by observational data. It is proposed that the location of the plume is primarily governed by the sea level structure away from the coast and that coastally upwelled water is passively advected offshore through regions of low sea level. Analysis of the surface wind-stress fields show significant spatial variability associated with the predominantly cyclonic mean wind-stress curl, with relatively weak curl observed in the region south of Ras al Madraka and north of Ras Marbat. Decomposition of the surface wind-stress fields through Principal Component Analysis shows that, at certain periods, the development of strong along-shore winds and cyclonic wind-stress curl in the region north of Ras al Madraka. This information, combined with concurrent observations of TOPEX/POSEIDON sea-level-anomalies (SLAs), satellite derived sea-surface-temperatures (SST), and surface current measurements, shows that the combined effects of a strong along-shore wind field and positive wind-stress curl forces a depression in sea level in the region north of Ras al Madraka. The sea level gradient, caused by the presence of a sustained high sea level to the south of Ras al Madraka, causes geostrophic advection of coastally upwelled waters away from the shelf. Acoustic Doppler Current Profiler (ADCP) velocity measurements along with SST maps further prove that the upwelled water is geostrophically advected offshore as opposed to being an offshore deflection of a wind-driven coastal current. Comparison of interannual features in the TOPEX/POSEIDON SLAs suggest that the plumes coming off coast in the Oman upwelling zone may not be directly linked to the coastal topography or bathymetry but are a result of interaction between mesoscale variations in the wind field and the underlying ocean. The strong along-shore winds and cyclonic wind-stress curl to the north of Ras al Madraka becomes enhanced when the Findlater Jet moves closer to the Oman coast than its mean position.}, number={10-11}, journal={DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY}, author={Manghnani, V and Morrison, JM and Hopkins, TS and Bohm, E}, year={1998}, pages={2027–2052} }
 @article{xie_pietrafesa_bohm_zhang_li_1998, title={Evidence and mechanism of Hurricane Fran induced cooling in the Charleston trough}, volume={25}, ISSN={["0094-8276"]}, DOI={10.1029/98GL00180}, abstractNote={Evidence of enhanced sea surface cooling during and following the passage of Hurricane Fran in September 1996 over an oceanic depression located on the ocean margin offshore of Charleston, South Carolina (referred to as the Charleston Trough), [Pietrafesa, 1983] is documented. Approximately 4C° of sea surface temperature (SST) reduction within the Charleston Trough following the passage of Hurricane Fran was estimated based on SST imagery from Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-14 polar orbiting satellite. Simulations using a three-dimensional coastal ocean model indicate that the largest SST reduction occurred within the Charleston Trough. This SST reduction can be explained by oceanic mixing due to storm-induced internal inertia-gravity waves.}, number={6}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Xie, L and Pietrafesa, LJ and Bohm, E and Zhang, C and Li, X}, year={1998}, month={Mar}, pages={769–772} }
 @article{bohm_demetriou_reich_rosen_1998, title={Model reference adaptive control of distributed parameter systems}, volume={36}, number={1}, journal={SIAM Journal on Control and Optimization}, author={Bohm, M. and Demetriou, M. A. and Reich, S. and Rosen, I. G.}, year={1998}, pages={33–81} }