Menezes
Viviane V.
Menezes
Viviane V.
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ArticleStatistical assessment of sea-surface salinity from SMAP: Arabian sea, Bay of Bengal and a promising Red Sea application(MDPI, 2020-02-01) Menezes, Viviane V.Sea-surface salinity (SSS) is an essential climate variable connected to Earth’s hydrological cycle and a dynamical component of ocean circulation, but its variability is not well-understood. Thanks to Argo floats, and the first decade of salinity remote sensing, this is changing. While satellites can retrieve salinity with some confidence, accuracy is regionally dependent and challenging within 500–1000 km offshore. The present work assesses the first four years of the National Aeronautics and Space Administration’s Soil Moisture Active Passive (SMAP) satellite in the North Indian Ocean. SMAP’s improved spatial resolution, better mitigation for radio-frequency interference, and land contamination make it particularly attractive to study coastal areas. Here, regions of interest are the Bay of Bengal, the Arabian Sea, and the extremely salty Red Sea (the last of which has not yet received attention). Six SMAP products, which include Levels 2 and 3 data, were statistically evaluated against in situ measurements collected by a variety of instruments. SMAP reproduced SSS well in both the Arabian Sea and the Bay of Bengal, and surprisingly well in the Red Sea. Correlations there were 0.81–0.93, and the root-mean-square difference was 0.38–0.67 for Level 3 data.
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ArticleAdvective pathways and transit times of the Red Sea Overflow Water in the Arabian Sea from Lagrangian simulations(Elsevier, 2021-11-05) Menezes, Viviane V.The present study investigates the advective pathways and transit times of virtual particles released in the Red Sea outflow area as a proxy for the poorly understood spreading of the Red Sea Overflow Water (RSOW) in the Arabian Sea. This work uses the Parcels toolbox, a Lagrangian framework, to simulate tens of thousands of trajectories under different initial conditions. Six different Lagrangian simulations are performed at isobaric and isopycnal surfaces within the RSOW layer. All simulations are based on the eddy-rich GLORYS12 reanalysis that merges almost all in-situ (temperature–salinity) and satellite observations collected over the last two decades into a dynamical framework. This study shows that GLORYS12 reproduces relatively well the climatological seasonal cycle of the RSOW to the Gulf of Aden and essential characteristics of the exchange at the Strait of Bab al-Mandab. Statistical comparisons between synthetic trajectories and RAFOS floats in the Gulf of Aden corroborate the quality of GLORYS12 velocity fields used for the Lagrangian simulations. Six main advective pathways are uncovered (by order of preference): Southwest, Northwest, Socotra Passage, Central, Eastern, and Southern. Trajectories from Argo floats give observational support for some of these paths. Although most particles are exported out of the Arabian Sea off Somalia, the simulations reveal robust connectivity of the RSOW to the Arabian Sea interior and its eastern boundary. The fact that particles have long trajectories in the interior increases the potential of RSOW mixing with the fresher and oxygen-poor ambient waters. Thus, these pathways may have profound implications for the salt and oxygen budgets in the Arabian Sea and beyond since the RSOW is also part of the global overturning circulation and exported out of the Indian Ocean via the Agulhas Current. Transit time distributions indicate that it takes about six months for outflow-originated particles to spread over the entire Gulf of Aden and one to three years to be exported along the western boundary, toward Somalia (Socotra Passage and Southwest pathways) and off the Yemeni–Omani coast (Northwest Pathway). In contrast, reaching the eastern boundary takes much longer. North of 14N, the most frequent time is around 10–15 years, and about 20–25 years at the southeastern Arabian Sea. Hence, the RSOW can often carry oxygen to the western boundary but not to the eastern basin. This may contribute to the eastern shift of the Arabian Sea Oxygen Minimum Zone, a subject that deserves investigation.
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ArticleAccelerated freshening of Antarctic Bottom Water over the last decade in the Southern Indian Ocean(American Association for the Advancement of Science, 2017-01-25) Menezes, Viviane V. ; Macdonald, Alison M. ; Schatzman, CourtneySouthern Ocean abyssal waters, in contact with the atmosphere at their formation sites around Antarctica, not only bring signals of a changing climate with them as they move around the globe but also contribute to that change through heat uptake and sea level rise. A repeat hydrographic line in the Indian sector of the Southern Ocean, occupied three times in the last two decades (1994, 2007, and, most recently, 2016), reveals that Antarctic Bottom Water (AABW) continues to become fresher (0.004 ± 0.001 kg/g decade−1), warmer (0.06° ± 0.01°C decade−1), and less dense (0.011 ± 0.002 kg/m3 decade−1). The most recent observations in the Australian-Antarctic Basin show a particularly striking acceleration in AABW freshening between 2007 and 2016 (0.008 ± 0.001 kg/g decade−1) compared to the 0.002 ± 0.001 kg/g decade−1 seen between 1994 and 2007. Freshening is, in part, responsible for an overall shift of the mean temperature-salinity curve toward lower densities. The marked freshening may be linked to an abrupt iceberg-glacier collision and calving event that occurred in 2010 on the George V/Adélie Land Coast, the main source region of bottom waters for the Australian-Antarctic Basin. Because AABW is a key component of the global overturning circulation, the persistent decrease in bottom water density and the associated increase in steric height that result from continued warming and freshening have important consequences beyond the Southern Indian Ocean.
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ArticleSurface heat fluxes over the northern Arabian Gulf and the northern Red Sea: Evaluation of ECMWF-ERA5 and NASA-MERRA2 reanalyses(MDPI, 2019-08-28) Al Senafi, Fahad ; Anis, Ayal ; Menezes, Viviane V.The air–sea heat fluxes in marginal seas and under extreme weather conditions constitute an essential source for energy transport and mixing dynamics. To reproduce these effects in numerical models, we need a better understanding of these fluxes. In response to this demand, we undertook a study to examine the surface heat fluxes in the Arabian Gulf (2013 to 2014) and Red Sea (2008 to 2010)—the two salty Indian Ocean marginal seas. We use high-quality buoy observations from offshore meteorological stations and data from two reanalysis products, the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA2) from the National Aeronautics and Space Administration (NASA) and ERA5, the fifth generation of the European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalyses of global climate. Comparison of the reanalyses with the in situ-derived fluxes shows that both products underestimate the net heat fluxes in the Gulf and the Red Sea, with biases up to −45 W/m 2 in MERRA2. The reanalyses reproduce relatively well the seasonal variability in the two regions and the effects of wind events on air–sea fluxes. The results suggest that when forcing numerical models, ERA5 might provide a preferable dataset of surface heat fluxes for the Arabian Gulf while for the Red Sea the MERRA2 seems preferable.
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ArticleProgress in understanding of Indian Ocean circulation, variability, air-sea exchange, and impacts on biogeochemistry(European Geosciences Union, 2021-11-26) Phillips, Helen E. ; Tandon, Amit ; Furue, Ryo ; Hood, Raleigh R. ; Ummenhofer, Caroline C. ; Benthuysen, Jessica A. ; Menezes, Viviane V. ; Hu, Shijian ; Webber, Ben ; Sanchez-Franks, Alejandra ; Cherian, Deepak A. ; Shroyer, Emily L. ; Feng, Ming ; Wijesekera, Hemantha W. ; Chatterjee, Abhisek ; Yu, Lisan ; Hermes, Juliet ; Murtugudde, Raghu ; Tozuka, Tomoki ; Su, Danielle ; Singh, Arvind ; Centurioni, Luca R. ; Prakash, Satya ; Wiggert, Jerry D.Over the past decade, our understanding of the Indian Ocean has advanced through concerted efforts toward measuring the ocean circulation and air–sea exchanges, detecting changes in water masses, and linking physical processes to ecologically important variables. New circulation pathways and mechanisms have been discovered that control atmospheric and oceanic mean state and variability. This review brings together new understanding of the ocean–atmosphere system in the Indian Ocean since the last comprehensive review, describing the Indian Ocean circulation patterns, air–sea interactions, and climate variability. Coordinated international focus on the Indian Ocean has motivated the application of new technologies to deliver higher-resolution observations and models of Indian Ocean processes. As a result we are discovering the importance of small-scale processes in setting the large-scale gradients and circulation, interactions between physical and biogeochemical processes, interactions between boundary currents and the interior, and interactions between the surface and the deep ocean. A newly discovered regional climate mode in the southeast Indian Ocean, the Ningaloo Niño, has instigated more regional air–sea coupling and marine heatwave research in the global oceans. In the last decade, we have seen rapid warming of the Indian Ocean overlaid with extremes in the form of marine heatwaves. These events have motivated studies that have delivered new insight into the variability in ocean heat content and exchanges in the Indian Ocean and have highlighted the critical role of the Indian Ocean as a clearing house for anthropogenic heat. This synthesis paper reviews the advances in these areas in the last decade.
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ArticleEvaporative implications of dry-air outbreaks over the northern Red Sea.(American Geophysical Union, 2019-04-01) Menezes, Viviane V. ; Farrar, J. Thomas ; Bower, Amy S.We investigate the impacts of westward wind events on the Red Sea evaporation using the 35‐year second Modern‐Era Retrospective analysis for Research and Applications reanalysis and a 2‐year‐long record of in situ observations from a heavily instrumented air‐sea interaction mooring. These events are common during boreal winter, and their effects are similar to cold‐air outbreaks that occur in midpolar and subpolar latitudes. They cause extreme heat loss from the sea, which is dominated by latent heat fluxes. Different from cold‐air outbreaks, the intensified heat loss is due to the low relative humidity as we show through latent heat flux decomposition. Rainfall is negligible during these events, and we refer to them as dry‐air outbreaks. We also investigate the general atmospheric circulation pattern that favors their occurrence, which is associated with an intensified Arabian High at the north‐central portion of the Arabian Peninsula—a feature that seems to be an extension of the Siberian High. The analyses reveal that the westward winds over the northern Red Sea and the winter Shamal winds in the Persian Gulf are very likely to be part of the same subsynoptic‐scale feature. The second Modern‐Era Retrospective analysis for Research and Applications reanalysis indicates that the occurrence of westward wind events over the northern Red Sea has grown from 1980 to 2015, especially the frequency of large‐scale events, the cause of which is to be investigated. We hypothesize that dry‐air outbreaks may induce surface water mass transformation in the surface Red Sea Eastern Boundary Current and could represent a significant process for the oceanic thermohaline‐driven overturning circulation.
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ArticleInterannual variability of the South Indian Countercurrent(John Wiley & Sons, 2016-05-26) Menezes, Viviane V. ; Phillips, Helen E. ; Vianna, Marcio L. ; Bindoff, Nathaniel L.In the present work, we investigate the interannual variability of the South Indian Countercurrent (SICC), a major and still understudied current of the Indian Ocean circulation. To characterize the interannual variability of the SICC, four different data sets (altimetry, GLORYS, OFAM3, and SODA) are analyzed using multiple tools, which include Singular Spectrum Analysis and wavelet methods. The quasi-biennial band dominates the SICC low-frequency variance, with the main peak in the 1.5–1.8 year interval. A secondary peak (2.1–2.5 year) is only found in the western basin. Interannual and decadal-type modulations of the quasi-biennial signal are also identified. In addition, limitations of SODA before the 1960s in the SICC region are revealed. Within the quasi-biennial band, the SICC system presents two main patterns with a multiple jet structure. One pattern is characterized by a robust northern jet, while in the other the central jet is well developed and northern jet is weaker. In both patterns, the southern jet has always a strong signature. When the northern SICC jet is stronger, the northern cell of the subtropical gyre has a triangular shape, with its southern limb having a strong equatorward slant. The quasi-biennial variability of the SICC is probably related to the Indian Ocean tropical climate modes that are known to have a strong biennial characteristic.
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ArticleWestward mountain-gap wind jets of the northern Red Sea as seen by QuikSCAT(Elsevier, 2018-03-19) Menezes, Viviane V. ; Farrar, J. Thomas ; Bower, Amy S.We analyse ten years of QuikSCAT satellite surface winds to statistically characterize the spatio-temporal variability of the westward mountain-gap wind jets over the northern Red Sea. These wind jets bring relatively cold and dry air from the Arabian Desert, increasing heat loss and evaporation over the region similar to cold-air outbreaks from mid and subpolar latitudes. QuikSCAT captures the spatial structure of the wind jets and agrees well with in situ observations from a heavily instrumented mooring in the northern Red Sea. The local linear correlations between QuikSCAT and in situ winds are 0.96 (speed) and 0.85 (direction). QuikSCAT also reveals that cross-axis winds such as the mountain-gap wind jets are a major component of the regional wind variability. The cross-axis wind pattern appears as the second (or third) mode in the four vector Empirical Orthogonal Function analyses we performed, explaining between 6% to 11% of the wind variance. Westward wind jets are typical in winter, especially in December and January, but with strong interannual variability. Several jets can occur simultaneously and cover a large latitudinal range of the northern Red Sea, which we call large-scale westward events. QuikSCAT recorded 18 large-scale events over ten years, with duration between 3 to 8 days and strengths varying from 3–4 to 9–10 m/s. These events cause large changes in the wind stress curl pattern, imposing a remarkable sequence of positive and negative curl along the Red Sea main axis, which might be a wind forcing mechanism for the oceanic mesoscale circulation.
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ArticleInterannual variability of red sea overflow water pathways in the Western Arabian Sea in an eddy rich reanalysis(Elsevier, 2023-03-30) Menezes, Viviane V.The present study investigates the interannual variability of the advective pathways and transit times of the Red Sea Overflow Water (RSOW) in the western Arabian Sea using virtual particles as a proxy indicator for the poorly understood RSOW spreading. The Lagrangian simulations are based on the GLORYS12 eddy-rich reanalysis (1/12°), which assimilates most satellite and in situ observations from 1993 to 2018. Statistical analysis of particle positions reveals the Gulf's mouth is always the main RSOW export route out of the Gulf of Aden. Moreover, there is substantial interannual variability in the three RSOW pathways in the western Arabian Sea, which are consistent with in-situ salinity variability at the RSOW layer. The faster Socotra pathway is strongest for particles released in 1998–1999 and 2012 and almost non-existent for the ones released in 2006–2007. The strongest state of the Socotra pathway co-occurs with some of the most powerful El-Nino/Southern Oscillation and Indian Ocean Dipole events in history. A decadal seesaw stands out between the Northwest pathway, which advects RSOW northward offshore the Arabian Peninsula, and the Southwest pathway, which advects RSOW southward to the Somali Basin along the eastern side of Socotra. While the Northwest pathway strengthened from 1996 to 2011, the Southwest weakened. These changes are associated with interannual variability in the western boundary undercurrents and subsurface eddy kinetic energy. Interestingly, the Northwest pathway trajectories are eddy-dominated, in striking contrast with the Socotra and Southwest pathways, in which western boundary undercurrents are major players. This fact suggests that eddy-induced transport is likely to have a significant role in spreading the RSOW northward. No considerable interannual variability in transit times is detected for any pathway.
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ArticleAutumnal equinox shift in Arctic surface energy budget: Beaufort‐Chukchi Seas case study(American Geophysical Union, 2024-05-27) Carrigg, Joseph ; Yu, Lisan ; Menezes, Viviane V. ; Chen, YanxuThis study examines the annual cycle of the Surface Energy Budget (SEB) in the Beaufort-Chukchi seas, focusing on the autumn transition. Shipboard measurements from NASA's Salinity and Stratification at the Sea Ice Edge (SASSIE) experiment (8 September–2 October 2022) and satellite flux analysis for the entire 2022 were utilized to provide a comprehensive perspective of the SEB's seasonal dynamics. An important finding is the alignment of SEB’s autumnal transition with the September 22 equinox, marking the onset of prolonged Arctic darkness. This transition involved a shift from the summertime radiative heating to cooling conditions, characterized by outgoing longwave radiation surpassing incoming solar radiation and a notable increase in synoptic turbulent latent and sensible heat flux variability. The increased turbulent heat fluxes after the equinox were associated with increased occurrences of short-duration cold air outbreaks. These outbreaks seem to originate from cold mesoscale surface winds transitioning from cooling landmasses or ice caps to the warmer seas, driven by differential cooling rates between land/ice and ocean as solar irradiance declined. Turbulent heat losses, outpacing longwave emission by more than fivefold, accelerated ocean surface cooling in the subsequent 2 months, leading to the complete freeze-up of the Beaufort-Chukchi seas by late November. These findings underscore the substantial influence of astronomical seasons on the SEB, emphasizing their crucial role in Arctic climate dynamics.
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ArticleDeep Argo observations of Antarctic Bottom Water in the Deep Fracture Zones of the Southwest Indian Ridge(American Geophysical Union, 2024-07-22) Menezes, Viviane V. ; Robbins, Pelle E. ; Furey, Heather H. ; Mazloff, Matthew R.The Madagascar Basin is the primary pathway for Antarctic Bottom Water to ventilate the entire western Indian Ocean as part of the Global Overturning Circulation. The only way for this water mass to reach this basin is by crossing the Southwest Indian Ridge through its deep fracture zones. However, due to the scarcity of observations, the Antarctic Bottom Water presence has only been well-established in the Atlantis II fracture zone. In May 2023, the Deep Madagascar Basin Experiment deployed three Deep SOLO Argo floats in the exit of the fracture zones that were more likely to transport Antarctic Bottom Water: Atlantis II, Novara, and Melville. These floats have been collecting temperature and salinity profiles every 3–5 days with high vertical resolution in the deep ocean. In the present paper, we use the first 7 months of float data to characterize the Antarctic Bottom Water in the deep fracture zone area, revisiting a half-century puzzle about the Melville contribution. We also collected shipboard-based profiles to calibrate float salinity and show it is within the Deep Argo program target accuracy. We find Antarctic Bottom Water in both Melville and Novara fracture zones, not only in Atlantis II. This is the first time the Novara contribution has been revealed. The floats also uncover their distinct properties, which may result from the different mixing histories.