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1
Carpenter, Siri. "Polluted Air Chokes Northern Indian Ocean." Science News 155, no. 25 (June 19, 1999): 389. http://dx.doi.org/10.2307/4011545.
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Chen, Jiepeng, Jin-Yi Yu, Xin Wang, and Tao Lian. "Different Influences of Southeastern Indian Ocean and Western Indian Ocean SST Anomalies on Eastern China Rainfall during the Decaying Summer of the 2015/16 Extreme El Niño." Journal of Climate 33, no. 13 (July 1, 2020): 5427–43. http://dx.doi.org/10.1175/jcli-d-19-0777.1.
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ABSTRACTPrevious studies linked the increase of the middle and low reaches of the Yangtze River (MLRYR) rainfall to tropical Indian Ocean warming during extreme El Niños’ (e.g., 1982/83 and 1997/98 extreme El Niños) decaying summer. This study finds the linkage to be different for the recent 2015/16 extreme El Niño’s decaying summer, during which the above-normal rainfalls over MLRYR and northern China are respectively linked to southeastern Indian Ocean warming and western tropical Indian Ocean cooling in sea surface temperatures (SSTs). The southeastern Indian Ocean warming helps to maintain the El Niño–induced anomalous lower-level anticyclone over the western North Pacific Ocean and southern China, which enhances moisture transport to increase rainfall over MLRYR. The western tropical Indian Ocean cooling first enhances the rainfall over central-northern India through a regional atmospheric circulation, the latent heating of which further excites a midlatitude Asian teleconnection pattern (part of circumglobal teleconnection) that results in an above-normal rainfall over northern China. The western tropical Indian Ocean cooling during the 2015/16 extreme El Niño is contributed by the increased upward latent heat flux anomalies associated with enhanced surface wind speeds, opposite to the earlier two extreme El Niños.
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Banerji, Upasana S., P. Arulbalaji, and D. Padmalal. "Holocene climate variability and Indian Summer Monsoon: An overview." Holocene 30, no. 5 (January 8, 2020): 744–73. http://dx.doi.org/10.1177/0959683619895577.
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The response of the Indian Summer Monsoon (ISM) to forcing factors and climate variables has not yet fully explored, even though the ISM plays a pivotal role in the socio-economics of the Indian subcontinent and nearby areas. The ISM progression over Indian landmass is a manifestation of the Intertropical Convergence Zone (ITCZ) migration over the northern Indian Ocean and the Indian subcontinent. The recent anomalous behaviour of ISM raises the need for a better understanding of its spatio-temporal changes during the ongoing interglacial period termed as the Holocene period. The Holocene period has been classified further based on the globally observed abrupt climatic events at 8.2 and 4.2 ka. The 8.2 ka global cooling events have been recorded from northern Indian Ocean marine archives but limited records from the continental archives of the Indian landmass has demonstrated the 8.2 ka event. At the same time, the 4.2 ka dry climate has been endorsed by both marine as well as continental records and agrees with the global studies. During the ‘Little Ice Age’ (LIA), in the India subcontinent, wet conditions prevailed in the northern, central and western regions while a dry climate existed over the greater part of peninsular India. The present review offers an account of ISM signatures and possible mechanisms associated with the monsoon variability in the Indian subcontinent and the northern Indian Ocean during the Holocene period.
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Panchang, Rajani, and Mugdha Ambokar. "Ocean acidification in the Northern Indian ocean : A review." Journal of Asian Earth Sciences 219 (October 2021): 104904. http://dx.doi.org/10.1016/j.jseaes.2021.104904.
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Lee Drbohlav, Hae-Kyung, and V. Krishnamurthy. "Spatial Structure, Forecast Errors, and Predictability of the South Asian Monsoon in CFS Monthly Retrospective Forecasts." Journal of Climate 23, no. 18 (September 15, 2010): 4750–69. http://dx.doi.org/10.1175/2010jcli2356.1.
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Abstract The spatial structure of the boreal summer South Asian monsoon in the ensemble mean of monthly retrospective forecasts by the Climate Forecast System of the National Centers for Environmental Prediction is examined. The forecast errors and predictability of the model are assessed. Systematic errors in the forecasts consist of deficient rainfall over India, excess rainfall over the Arabian Sea, and a dipole structure over the equatorial Indian Ocean. On interannual time scale during 1981–2003, two different characteristics of the monsoon are recognized—both in observation and forecasts. One feature seems to indicate that the monsoon is regionally controlled, while the other shows a strong relation with El Niño–Southern Oscillation (ENSO). The spatial structure of the regional monsoon can be characterized by the dominant rainfall between the latitudes of 15°N and 5°S in the western Indian Ocean. The maximum precipitation anomalies in the northern Arabian Sea are associated with the cyclonic circulation, while the precipitation anomalies in the equatorial western Indian Ocean accompany the easterlies over the equatorial Indian Ocean. In the ENSO-related monsoon, strong positive precipitation anomalies prevail from the equatorial eastern Indian Ocean to the western Pacific, inducing westerlies over the equatorial Indian Ocean. The spatial structure of the forecast error shows that the model is inclined to predict the ENSO-related feature more accurately than the regional feature. The predictability is found to be lower over certain areas in the northern and equatorial eastern Indian Ocean. The predictability errors in the northern Indian Ocean diminish for longer forecast leads, presumably because the impact of different initial conditions dissipates with time. On the other hand, predictability errors over the equatorial eastern Indian Ocean grow as the forecast lead increases.
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Gaye-Haake, B., M. V. S. Guptha, V. S. N. Murty, and V. Ittekkot. "Biogeochemical Processes in the Northern Indian Ocean." Deep Sea Research Part II: Topical Studies in Oceanography 52, no. 14-15 (July 2005): 1845–47. http://dx.doi.org/10.1016/j.dsr2.2005.06.001.
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Singh, D. D. "Strain deformation in the northern Indian Ocean." Marine Geology 79, no. 1-2 (February 1988): 105–18. http://dx.doi.org/10.1016/0025-3227(88)90159-4.
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Perwita, Anak Agung Banyu. "The Implementation of India’s Maritime Doctrine to Respond China Naval Presence in Indian Ocean Region." Indonesian Journal of Peace and Security Studies (IJPSS) 2, no. 1 (July 26, 2020): 31–48. http://dx.doi.org/10.29303/ijpss.v2i1.38.
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Indian Ocean is a strategic and crucial location of the region and became the centre of global politics. Indian Ocean Region (IOR) has several important gulfs, straits, bays and seas within which most of it located in the northern part of the ocean. Major shipment routes intersect its enormous area, with crucial choke points and water courses connecting Indian Ocean to other main ocean parts on the earth. Indian Ocean region is part of China’s significant security interests, where China is currently leading to an ever advanced military existence within the area. China’s overpowering strategic focus in the Indian Ocean is the preservation of their maritime trading routes, particularly those transporting oil and gas that the Chinese economy relies upon. Indian Ocean Region is at the top of Indian policy priorities. India’s vision for Indian Ocean Region is deep-rooted in preceding cooperation in the region and to use their capabilities for the benefit of all in their common maritime home. The Indian Ocean holds particular importance for India. India is definitely trying to maintain their national security interests in Indian Ocean. In response to the condition in the Indian Ocean, India implemented its Indian Maritime Doctrine which is applied through Indian Navy as the way to respond China’s naval existence in IOR since 2008. This implementation brings the sources of its naval application as an effort to balance China’s naval presence in IOR through its doctrine. The unilateral naval effort is held to respond China in IOR. Moreover, a further effort of Indian navy is needed through bilateral cooporation that will further support its unilateral effort in balancing China’s active presence in the region.
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Schott, Friedrich A. "Shallow overturning circulation of the Western Indian Ocean." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 363, no. 1826 (January 15, 2005): 143–49. http://dx.doi.org/10.1098/rsta.2004.1483.
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The Indian Ocean differs from the other two oceans in not possessing an eastern equatorial upwelling regime. Instead, the upwelling occurs dominantly in the northwestern Arabian Sea and, to a lesser degree, around the Indian subcontinent. Subduction, on the other hand, occurs dominantly in the Southern Hemisphere. The result is a shallow Cross–Equatorial Cell connecting both regimes. The northward flow at thermocline levels occurs as part of the Somali Current and the southward upper–layer return flow is carried by the Ekman transports that are directed southward in both hemispheres. The main forcing is by the Southwest Monsoon that overwhelms the effects of the Northeast Monsoon and is the cause for the annual mean Northern Hemisphere upwelling and southward Ekman transports. In the Southern Hemisphere, the annual mean upwelling at the northern rim of the Southeast Trades causes a zonally extended open–ocean upwelling regime that is apparent in isopycnal doming in the 3–12○ S band; it drives a shallow Subtropical Cell.
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Meehl, Gerald A., Julie M. Arblaster, and Johannes Loschnigg. "Coupled Ocean–Atmosphere Dynamical Processes in the Tropical Indian and Pacific Oceans and the TBO." Journal of Climate 16, no. 13 (July 1, 2003): 2138–58. http://dx.doi.org/10.1175/2767.1.
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Abstract The transitions (from relatively strong to relatively weak monsoon) in the tropospheric biennial oscillation (TBO) occur in northern spring for the south Asian or Indian monsoon and northern fall for the Australian monsoon involving coupled land–atmosphere–ocean processes over a large area of the Indo-Pacific region. Transitions from March–May (MAM) to June–September (JJAS) tend to set the system for the next year, with a transition to the opposite sign the following year. Previous analyses of observed data and GCM sensitivity experiments have demonstrated that the TBO (with roughly a 2–3-yr period) encompasses most ENSO years (with their well-known biennial tendency). In addition, there are other years, including many Indian Ocean dipole (or zonal mode) events, that contribute to biennial transitions. Results presented here from observations for composites of TBO evolution confirm earlier results that the Indian and Pacific SST forcings are more dominant in the TBO than circulation and meridional temperature gradient anomalies over Asia. A fundamental element of the TBO is the large-scale east–west atmospheric circulation (the Walker circulation) that links anomalous convection and precipitation, winds, and ocean dynamics across the Indian and Pacific sectors. This circulation connects convection over the Asian–Australian monsoon regions both to the central and eastern Pacific (the eastern Walker cell), and to the central and western Indian Ocean (the western Walker cell). Analyses of upper-ocean data confirm previous results and show that ENSO El Niño and La Niña events as well as Indian Ocean SST dipole (or zonal mode) events are often large-amplitude excursions of the TBO in the tropical Pacific and Indian Oceans, respectively, associated with anomalous eastern and western Walker cell circulations, coupled ocean dynamics, and upper-ocean temperature and heat content anomalies. Other years with similar but lower-amplitude signals in the tropical Pacific and Indian Oceans also contribute to the TBO. Observed upper-ocean data for the Indian Ocean show that slowly eastward-propagating equatorial ocean heat content anomalies, westward-propagating ocean Rossby waves south of the equator, and anomalous cross-equatorial ocean heat transports contribute to the heat content anomalies in the Indian Ocean and thus to the ocean memory and consequent SST anomalies, which are an essential part of the TBO.
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Ding, Qinghua, and Bin Wang. "Predicting Extreme Phases of the Indian Summer Monsoon*." Journal of Climate 22, no. 2 (January 15, 2009): 346–63. http://dx.doi.org/10.1175/2008jcli2449.1.
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Abstract Extreme active and break phases of the Indian summer monsoon (ISM) often bring about devastating floods and severe draughts. Here it is shown that these extreme phases exhibit distinctive precursory circulation conditions in both the tropics and extratropics over a range of antecedent periods. The extremely active monsoon over northern India is preceded by a strengthening of the upper-tropospheric central Asian high and enhancement of the tropical convection over the equatorial Indian Ocean and the South China Sea. The concurrent buildup of the anomalous high over central Asia and the arrival of tropical convection over northern India increase the likelihood of occurrence of a heavy rainy period there. Similarly, the concurrent anomalous low over central Asia and the arrival of suppressed convection originating from the equatorial Indian Ocean and the South China Sea precede extremely strong monsoon breaks over northern India. Two predictors can be used to predict the extreme active/break phases of the northern ISM: normalized 200-hPa geopotential height over central Asia and outgoing longwave radiation over southern India. Once the mean of the two predictors exceeds a threshold unit (1.0), an extreme phase is anticipated to occur over northern India after 4–5 days and reach peak intensity after an additional 2 days. In general, an event forecast by this simple scenario has a 40% probability of developing into an extreme phase, which is normally a small probability event (a less than 4% occurrence).
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Li, Shuai, Li Liu, Zhiqiang Gong, Jie Yang, and Guolin Feng. "The Enhancement of the Summer Precipitation Teleconnection between India and the Northern Part of Eastern China after the Late 1990s." Journal of Climate 36, no. 9 (May 2023): 3043–62. http://dx.doi.org/10.1175/jcli-d-22-0366.1.
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Abstract As subsystems of the Asian summer monsoon, summer precipitation variations in India and the northern part of eastern China (NEC) are physically connected. This study noted that the connection has been significantly enhanced after 1999 compared to 1979–98, which is due to the strengthened water vapor transportation connection between the two regions. That is associated with interdecadal variations of the combined effects of El Niño–Southern Oscillation (ENSO) and sea surface temperature anomalies (SSTAs) over the tropical Indian Ocean (TIO) on the northwest Pacific subtropical high (NWPSH) and the Indo-Pacific Walker cell. Against the background of La Niña, the strengthened NWPSH and Indo-Pacific Walker cell favor water vapor transport to India and the NEC since 1999. Accordingly, summer precipitation in the two regions increases simultaneously, leading to the enhancement of the summer precipitation teleconnection between them. In addition, the influence of TIO SSTAs and the Indian Ocean dipole (IOD) on Indo-Pacific circulations decreases, which further enhances the relative importance of ENSO on the summer precipitation in the two regions. However, during 1979–98, La Niña SSTAs has weak effects on the NWPSH and Indo-Pacific Walker cell, the negative TIO SSTAs significantly weaken NWPSH, and the negative IOD also obstructs the westward extension of the Indo-Pacific Walker cell. Circulations and water vapor transportation related to the Indian Ocean and NEC summer precipitation are inconsistent, resulting in a weak precipitation teleconnection between them. The above conclusions are also validated by extreme case analysis and CMIP6 models. Significance Statement This paper mainly studies the influences of different types of ENSO and Indian Ocean SSTAs on the interdecadal variations of the summer precipitation relationship between India and the northern part of eastern China (NEC). We find that the summer precipitation relationship between them is strengthened again after 1999, which deepens the understanding of summer precipitation in Asia and has great significance for improving dynamic models’ prediction skills. The interdecadal variations of the combined effects of the Indian and Pacific Oceans are the fundamental reasons for the interdecadal variations of precipitation relationships, which promotes the understanding of interactions of different oceans and their impacts on Asian climate.
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SINGH, M. S., and B. Lakshmanaswamy. "Evolution of two troughs in the tropical Indian Ocean and their characteristic features." MAUSAM 43, no. 4 (December 31, 2021): 395–98. http://dx.doi.org/10.54302/mausam.v43i4.3507.
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Evolution and characteristic features of double trough systems in the tropical Indian Ocean have been studied with the help of Climatological Atlas (Part I andIl) ~f the Tropical Indian Oc.ean (Hastenrath and Lamb 1979). It is confirmed that there are two troughs (Northern Hemisphere EquatorIal Trough and Southern Hemisphere Equatorial Trough) in this region (including south Asian landmass) all the year round, one in northern hemisphere and the other in southern. Both are migratory in nature and, perhaps, thermal in origin. In the convergent zones of the two troughs, there is extensive cloudiness. The migration of these trough systems during their respective summer seasons appear to be related to the extensive heating of the south Asian/ African land masses surrounding the Indian Ocean in north and west.
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RAY, DWIJESH, SAUMITRA MISRA, RANADIP BANERJEE, and DOMINIQUE WEIS. "Geochemical implications of gabbro from the slow-spreading Northern Central Indian Ocean Ridge, Indian Ocean." Geological Magazine 148, no. 3 (October 12, 2010): 404–22. http://dx.doi.org/10.1017/s001675681000083x.
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AbstractGabbro samples (c. < 0.4 Ma old) dredged from close to the ‘Vityaz Megamullion’ on the slow-spreading Northern Central Indian Ridge (NCIR, 18–22 mm yr−1) include mostly olivine gabbro and Fe–Ti oxide gabbro. The cumulate olivine gabbro shows ophitic to subophitic texture with early formed plagioclase crystals in mutual contact with each other, and a narrow range of compositions of olivine (Fo80–81), clinopyroxene (magnesium number: 85–87) and plagioclase (An67–70). This olivine gabbro could be geochemically cogenetic with the evolved oxide gabbro. These gabbro samples are geochemically distinct from the CIR gabbro occurring along the Vema, Argo and Marie Celeste transform faults and can further be discriminated from the associated NCIR basalts by their clinopyroxene (augite in gabbro, and diopsidic in basalts) and olivine (gabbro: Fo80–81, basalts: Fo82–88) compositions. Our major oxide, trace element and REE geochemistry analyses suggest that the gabbro and the NCIR basalts are also not cogenetic and had experienced different trends of geochemical evolution. The clinopyroxenes of the present NCIR gabbros are geochemically similar to primitive melt that is in equilibrium with mantle peridotite, and do not show any poikilitic texture with resorbed plagioclase; these results negate the possibility of these gabbros being a pre-existing cumulate that has been brought up to the shallower oceanic crust and interacted with the NCIR basalt. The Sr, Pb and Nd isotopic data of the gabbro substantially differ from those of the NCIR basalts and suggest significant contamination of the depleted mantle source of the gabbro, most likely by the Indian Ocean pelagic sediments. The Pb-isotope data suggest that the proportion of pelagic sediment that mixed in the depleted mantle source of the NCIR gabbro is much higher than the level of contamination observed for the Indian Ocean MORBs.
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Lee, S. Y., and T. Y. Koh. "Teleconnection between Australian winter temperature and Indian summer monsoon rainfall." Atmospheric Chemistry and Physics Discussions 11, no. 9 (September 22, 2011): 26415–40. http://dx.doi.org/10.5194/acpd-11-26415-2011.
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Abstract. The large-scale circulation over the Indian Ocean during the boreal summer raises the question of whether atmospheric conditions in Australia could influence conditions over the Indian subcontinent, despite the long passage of air over the Indian Ocean. Using a combination of reanalysis, satellite and in situ data, we argue that unusually low temperature over inland Australia during austral winter can enhance evaporation rate over the eastern tropical Indian Ocean, and hence enhance rainfall over western India after 10–18 days. Since extreme winter temperature in Australia is often associated with cold-air outbreaks, the above mechanism can be an example of how southern hemispheric mid-latitude weather can influence northern hemispheric monsoon rainfall.
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Ashalatha, B., C. Subrahmanyam, and R. N. Singh. "Carlsberg Ridge, northern Indian Ocean: gravity and isostasy." Geophysical Journal International 119, no. 1 (October 1994): 69–77. http://dx.doi.org/10.1111/j.1365-246x.1994.tb00913.x.
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Dutta, Koushik, Ravi Bhushan, and B. L. K. Somayajulu. "ΔR Correction Values for the Northern Indian Ocean." Radiocarbon 43, no. 2A (2001): 483–88. http://dx.doi.org/10.1017/s0033822200038376.
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Apparent marine radiocarbon ages are reported for the northern Indian Ocean region for the pre-nuclear period, based on measurements made in seven mollusk shells collected between 1930 and 1954. The conventional 14C ages of these shells range from 693 ± 44 to 434 ± 51 BP in the Arabian Sea and 511 ± 34 to 408 ± 51 BP in the Bay of Bengal. These ages correspond to mean ΔR correction values of 163 ± 30 yr for the northern Arabian Sea, 11 ± 35 yr for the eastern Bay of Bengal (Andaman Sea) and 32 ± 20 yr for the southern Bay of Bengal. Contrasting reservoir ages for these two basins are most likely due to differences in their thermocline ventilation rates.
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S. N. PANDEY, R. BHATLA, MANOJ K. SRIVASTAVA, and R. K. MALL. "Floods and hazardous heavy rainfall in India: Comparison between local versus oceanic impact." Journal of Agrometeorology 12, no. 1 (June 1, 2010): 40–43. http://dx.doi.org/10.54386/jam.v12i1.1265.
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India, leading to heavy rainfall. Such heavy rainfall result in floods for wider region of northern India, and, which, finally, causes loss of agriculture, human and animal’s life, outbreak of diseases/ epidemics, and thus affecting national economy. An attempt has therefore, been made to analyze the disastrous events that occurred in the summer monsoon months over different states in India for the period 1981-2000. The analyses included the raining event which were active, but, caused due to- or without the monsoonal-systems that were formed in north Indian Ocean. Results showed that West Bengal was the mostly affected state during monsoon season, where both, local as well as monsoonal systems were equally responsible for heavy rainfall/ flood events. The local atmospheric phenomenon affected highly to Uttar Pradesh, West Bengal, Gujarat, and Maharashtra, whereas for systems that were associated with the north Indian Ocean and Bay of Bengal, the states of West Bengal and Orissa were the mostly affected states. From the study, it may be concluded that all the heavy rainfall related disastrous weather events formed over different states in India was not only due to systems developed over Oceans, rather, local atmospheric phenomena had equally important contributor of similar affects, particularly for northern and western India.
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Jensen, Tommy G. "Wind-Driven Response of the Northern Indian Ocean to Climate Extremes*." Journal of Climate 20, no. 13 (July 1, 2007): 2978–93. http://dx.doi.org/10.1175/jcli4150.1.
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Abstract Composites of Florida State University winds (1970–99) for four different climate scenarios are used to force an Indian Ocean model. In addition to the mean climatology, the cases include La Niña, El Niño, and the Indian Ocean dipole (IOD). The differences in upper-ocean water mass exchanges between the Arabian Sea and the Bay of Bengal are investigated and show that, during El Niño and IOD years, the average clockwise Indian Ocean circulation is intensified, while it is weakened during La Niña years. As a consequence, high-salinity water export from the Arabian Sea into the Bay of Bengal is enhanced during El Niño and IOD years, while transport of low-salinity waters from the Bay of Bengal into the Arabian Sea is enhanced during La Niña years. This provides a venue for interannual salinity variations in the northern Indian Ocean.
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Nair, Vijayakumar S., Venugopalan Nair Jayachandran, Sobhan Kumar Kompalli, Mukunda M. Gogoi, and S. Suresh Babu. "Cloud condensation nuclei properties of South Asian outflow over the northern Indian Ocean during winter." Atmospheric Chemistry and Physics 20, no. 5 (March 16, 2020): 3135–49. http://dx.doi.org/10.5194/acp-20-3135-2020.
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Abstract. Extensive measurements of cloud condensation nuclei (CCN) and condensation nuclei (CN) concentrations in the South Asian outflow to the northern Indian Ocean were carried out on board an instrumented research vessel, as part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) during the winter season (January–February 2018). Measurements include a north–south transect across the South Asian plume over the northern Indian Ocean and an east–west transect over the equatorial Indian Ocean (∼2∘ S), which is far away from the continental sources. South Asian outflow over the northern Indian Ocean is characterized by the high values of CCN number concentration (∼5000 cm−3), low CCN activation efficiency (∼25 %) and a steep increase in CCN concentration with the increase in supersaturation. In contrast, low CCN concentration (∼1000 cm−3) with flat supersaturation spectra was found over the equatorial Indian Ocean. The CCN properties exhibited significant dependence on the geometric mean diameter (GMD) of the aerosol number size distribution, and CCN activation efficiency decreased to low values (<20 %) at the time of new-particle formation events over near-coastal and remote oceanic regions. The analysis of the activation efficiencies for the “similar” aerosol size distributions over the northern Indian Ocean indicated the primary role of aerosol number size distribution on CCN activation efficiency. The dependence of CCN properties and activation efficiency on size-segregated aerosol number concentration, especially during the ultrafine (<100 nm) particle events, is investigated in detail for the first time over the region.
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Shih, Hsi-Te, Benny K. K. Chan, and Peter K. L. Ng. "Tubuca alcocki, a new pseudocryptic species of fiddler crab from the Indian Ocean, sister to the southeastern African T. urvillei (H. Milne Edwards, 1852) (Crustacea, Decapoda, Brachyura, Ocypodidae)." ZooKeys 747 (March 29, 2018): 41–62. http://dx.doi.org/10.3897/zookeys.747.23468.
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A new pseudocryptic species of fiddler crab,Tubucaalcockisp. n., is described from the northern Indian Ocean. The new species was previously identified withT.urvillei(H. Milne Edwards, 1852), but can be distinguished by the structures of the anterolateral angle of the carapace and male first gonopod. The molecular data of the mitochondrial cytochrome oxidase subunit I gene shows that both are sister taxa and the divergence time is estimated at 2.2 million years ago, around the beginning of the Pleistocene. While the new species is widely distributed in the northern part of Indian Ocean, occurring from the Red Sea to India and the Andaman Sea;T.urvilleisensu stricto has a more restricted range, and is known only from southeastern Africa.
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Anderson, James R., and Peter Crozier. "Microstructure of Climate-Forcing Aerosols: Aircraft Traverses from Clean to Polluted Conditions in the Indian Ocean." Microscopy and Microanalysis 7, S2 (August 2001): 480–81. http://dx.doi.org/10.1017/s1431927600028476.
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The Indian Ocean Experiment (INDOEX) was conducted in Feb.-Mar. 1999 in a large area of the Indian Ocean, Bay of Bengal, and Arabian Sea to investigate climate forcing produced by pollutant aerosol particles being transported out of India, Pakistan, and Indochina during the Northeast (“Dry“) Monsoon2. Pollutant aerosols can be transported a thousand km or more by prevailing winds as far south as the Inter-tropical Convergence Zone (ITCZ), the convective band that separates Northern and Southern Hemisphere tropospheric air. We present here results from TEM examination of aerosol particles collected on INDOEX research flights of the NCAR C-130 aircraft.The climate forcing properties of sulfate aerosols over the oceans have long been recognized2. Sulfate and other particles scatter incoming solar radiation, reducing the amount of light (and heat) incident on the ocean surface and thus causing a cooling effect which may locally counter some of the warming effect due to greenhouse gases.
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Hoell, Andrew, Mathew Barlow, and Roop Saini. "Intraseasonal and Seasonal-to-Interannual Indian Ocean Convection and Hemispheric Teleconnections." Journal of Climate 26, no. 22 (October 29, 2013): 8850–67. http://dx.doi.org/10.1175/jcli-d-12-00306.1.
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Abstract Deep tropical convection over the Indian Ocean leads to intense diabatic heating, a main driver of the climate system. The Northern Hemisphere circulation and precipitation associated with intraseasonal and seasonal-to-interannual components of the leading pattern of Indian Ocean convection are investigated for November–April 1979–2008. The leading pattern of Indian Ocean convection is separated into intraseasonal and seasonal-to-interannual components by filtering an index of outgoing longwave radiation at 33–105 days and greater than 105 days, yielding Madden–Julian oscillation (MJO)- and El Niño–Southern Oscillation (ENSO)-influenced patterns, respectively. Observations and barotropic Rossby wave ray tracing experiments suggest that Indian Ocean convection can influence the ENSO-related hemispheric teleconnection pattern in addition to the regional Asian teleconnection. Equivalent barotropic circulation anomalies throughout the Northern Hemisphere subtropics are associated with both seasonal-to-interannual Indian Ocean convection and ENSO. The hemispheric teleconnection associated with seasonal-to-interannual Indian Ocean convection is investigated with ray tracing, which suggests that forcing over the Indian Ocean can propagate eastward across the hemisphere and back to Asia. The relationship between the seasonal-to-interannual component of Indian Ocean convection and ENSO is investigated in terms of a gradient in sea surface temperatures (SST) over the equatorial western Pacific Ocean. When the western Pacific SST gradient is strong during ENSO, strong Maritime Continent precipitation extends further westward into the Indian Ocean, which is accompanied by enhanced tropospheric Asian circulation, similar to the seasonal-to-interannual component of Indian Ocean convection. Analysis of the three strongest interannual convection seasons shows that the strong Indian Ocean pattern of ENSO can dominate individual seasons.
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Rashid, Harunur, Yang Wang, and Alexandra T. Gourlan. "Impact of Climate Change on Past Indian Monsoon and Circulation: A Perspective Based on Radiogenic and Trace Metal Geochemistry." Atmosphere 12, no. 3 (March 4, 2021): 330. http://dx.doi.org/10.3390/atmos12030330.
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The Indian summer monsoon (ISM), one of the dramatic illustrations of seasonal hydrological variability in the climate system, affects billions of lives. The ISM dominantly controls the northern Indian Ocean sea-surface salinity, mostly in the Bay of Bengal and the Andaman Sea, by the Ganga-Brahmaputra-Meghna and Irrawaddy-Salween rivers outflow and direct rainfall. In the past decade, numerous studies have used radiogenic neodymium (εNd) isotopes of seawater to link Indian subcontinent erosion and the ensuing increase in discharge that results in changes in the north Indian Ocean sea surface. Here we synthesized the state of the ISM and ocean circulation using the neodymium and hafnium isotopes from north Indian Ocean deep-sea sediments. Our data suggest that the Bay of Bengal and north Indian Ocean sea-surface conditions were most likely modulated by changes in the ISM strength during the last glacial-interglacial cycle. These findings contrast to the hypothesis that suggests that the bottom water neodymium isotopes of the northern Indian Ocean were modulated by switching between two distant sources, namely North Atlantic Deep Water and Antarctic bottom water. Furthermore, the consistency between the neodymium and hafnium isotopes during the last glacial maximum and Holocene suggests a weak and dry ISM and strong and wet conditions, respectively. These data also indicate that the primary source of these isotopes was the Himalayas. Our results support the previously published paleo-proxy records, indicating weak and strong monsoons for the same periods. Moreover, our data further support the hypothesis that the northern Indian Ocean neodymium isotopes were decoupled from the global ocean neodymium budget due to the greater regional influence by the great Ganga-Brahmaputra-Meghna and Irrawaddy-Salween discharge draining the Indian subcontinent to the Bay of Bengal and the Andaman Sea.
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Luffman, James J., Andréa S. Taschetto, and Matthew H. England. "Global and Regional Climate Response to Late Twentieth-Century Warming over the Indian Ocean." Journal of Climate 23, no. 7 (April 1, 2010): 1660–74. http://dx.doi.org/10.1175/2009jcli3086.1.
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Abstract The global and regional climate response to a warming of the Indian Ocean is examined in an ensemble of atmospheric general circulation model experiments. The most marked changes occur over the Indian Ocean, where the increase in tropical SST is found to drive enhanced convection throughout the troposphere. In the extratropics, the warming Indian Ocean is found to induce a significant trend toward the positive phase of the northern annular mode and also to enhance the Southern Hemisphere storm track over Indian Ocean longitudes as a result of stronger meridional temperature gradients. Convective outflow in the upper levels over the warming Indian Ocean leads to a trend in subsidence over the Indian and Asian monsoon regions extending southeastward to Indonesia, the eastern Pacific, and northern Australia. Regional changes in Australia reveal that this anomalous zone of subsidence induces a drying trend in the northern regions of the continent. The long-term rainfall trend is exacerbated over northeastern Australia by the anomalous anticyclonic circulation, which leads to an offshore trend in near-surface winds. The confluence of these two factors leads to a drying signal over northeastern Australia, which is detectable during austral autumn. The rapid, late twentieth-century warming of the Indian Ocean may have contributed to a component of the observed drying trend over northeastern Australia in this season via modifications to the vertical structure of the tropical wind field.
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Gao, Meng, Peter Sherman, Shaojie Song, Yueyue Yu, Zhiwei Wu, and Michael B. McElroy. "Seasonal prediction of Indian wintertime aerosol pollution using the ocean memory effect." Science Advances 5, no. 7 (July 2019): eaav4157. http://dx.doi.org/10.1126/sciadv.aav4157.
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As China makes every effort to control air pollution, India emerges as the world’s most polluted country, receiving worldwide attention with frequent winter (boreal) haze extremes. In this study, we found that the interannual variability of wintertime aerosol pollution over northern India is regulated mainly by a combination of El Niño and the Antarctic Oscillation (AAO). Both El Niño sea surface temperature (SST) anomalies and AAO-induced Indian Ocean Meridional Dipole SST anomalies can persist from autumn to winter, offering prospects for a prewinter forecast of wintertime aerosol pollution over northern India. We constructed a multivariable regression model incorporating El Niño and AAO indices for autumn to predict wintertime AOD. The prediction exhibits a high degree of consistency with observation, with a correlation coefficient of 0.78 (P < 0.01). This statistical model could allow the Indian government to forecast aerosol pollution conditions in winter and accordingly improve plans for pollution control.
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Wang, Lei, and Jin-Yi Yu. "A Recent Shift in the Monsoon Centers Associated with the Tropospheric Biennial Oscillation." Journal of Climate 31, no. 1 (December 15, 2017): 325–40. http://dx.doi.org/10.1175/jcli-d-17-0349.1.
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Abstract The tropospheric biennial oscillation (TBO) is conventionally considered to involve transitions between the Indian and Australian summer monsoons and the interactions between these two monsoons and the underlying Indo-Pacific Oceans. Here it is shown that, since the early 1990s, the TBO has evolved to mainly involve the transitions between the western North Pacific (WNP) and Australian monsoons. In this framework, the WNP monsoon replaces the Indian monsoon as the active Northern Hemisphere TBO monsoon center during recent decades. This change is found to be caused by stronger Pacific–Atlantic coupling and an increased influence of the tropical Atlantic Ocean on the Indian and WNP monsoons. The increased Atlantic Ocean influence damps the Pacific Ocean influence on the Indian summer monsoon (leading to a decrease in its variability) but amplifies the Pacific Ocean influence on the WNP summer monsoon (leading to an increase in its variability). These results suggest that the Pacific–Atlantic interactions have become more important to the TBO dynamics during recent decades.
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Clayson, Carol Anne, and Derrick Weitlich. "Variability of Tropical Diurnal Sea Surface Temperature*." Journal of Climate 20, no. 2 (January 15, 2007): 334–52. http://dx.doi.org/10.1175/jcli3999.1.
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Abstract A dataset consisting of daily diurnal warming values from 1996 through 2000 covering the global Tropics (30°N through 30°S) at 0.25° × 0.25° resolution has been created using a parameterization for the diurnal warming developed previously. The inputs to the parameterization are the peak shortwave solar radiation [determined from International Satellite Cloud Climatology Project (ISCCP) data] and daily averaged wind speed [determined from Special Sensor Microwave Imager (SSM/I) data]. Comparisons with Tropical Ocean Global Atmosphere (TOGA) Tropical Atmosphere Ocean (TAO) and Pilot Research Moored Array in the Tropical Atlantic (PIRATA) buoys show that the biases are small (mean bias is 0.0012°C; the standard deviation and correlation are 0.26°C and 0.74) and show no discernable geographic bias. The 5-yr average shows that throughout most regions the values are small, with higher values (approaching 1°C) in the northern Indian Ocean, the western equatorial Pacific, the equatorial eastern Pacific, and several coastal regions. An EOF analysis of the variability indicates that seasonal variability is the most dominant form for each of the basins; in the Atlantic and Pacific basins it is north–south following the solar cycle. In the Indian Ocean the seasonal cycle is dominated by monsoonal variability; both the northern and southern portions of the basin have above-mean or below-mean values at the same times. Seasonal shortwave variability is responsible for the second mode in the Indian Ocean. East–west dipole weight structures appear in the spatial patterns for mode 2 in the Pacific and mode 3 for the Atlantic and Indian Oceans. These modes also display seasonally varying characteristics, with late 1997 and early 1998 being somewhat anomalous in the Pacific and Indian Oceans.
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Khot, Mayura, A. K. Jaiswar, and Peter K. L. Ng. "The taxonomy of two species of Xenophthalmidae from Maharashtra, India, and the generic placement of Xenophthalmus garthii Sankarankutty, 1969 (Decapoda, Brachyura)." Crustaceana 92, no. 11-12 (December 5, 2019): 1337–48. http://dx.doi.org/10.1163/15685403-00003947.
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Abstract Two species of xenophthalmid crabs are recorded from the state of Maharashtra in northwestern India. Xenophthalmus garthii Sankarankutty, 1969, originally described from northern Kerala in India, is rediscovered, and the species proves to be a member of Anomalifrons Rathbun, 1931, a genus not previously known from the Indian Ocean. The taxonomy of this species is discussed and compared with its only congener, A. lightana Rathbun, 1931, from Southeast and East Asia. Xenophthalmus wolffii Takeda & Miyake, 1970, is recorded for first time from the coast of Mumbai; the species is otherwise known from various parts of the Indian Ocean.
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Varghese, Roma, Swadhin K. Behera, and Mukunda Dev Behera. "Significant Inverse Influence of Tropical Indian Ocean SST on SIF of Indian Vegetation during the Summer Monsoon Onset Phase." Remote Sensing 15, no. 7 (March 24, 2023): 1756. http://dx.doi.org/10.3390/rs15071756.
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Sea surface temperature (SST) substantially influences the land climate conditions through the co-variability of multiple climate variables, which in turn affect the structural and functional characteristics of terrestrial vegetation. Our study explored the varying responses of vegetation photosynthesis in India to the SST variations in the tropical Indian Ocean during the summer monsoon. To characterise the terrestrial photosynthetic activity, we used solar-induced chlorophyll fluorescence (SIF). Our results demonstrated a significant negative SST-SIF relationship during the onset phase of the summer monsoon: the SIF anomalies in the northern and central Indian regions decrease when strong warm SST anomalies persist in the tropical Indian Ocean. Further, SIF anomalies increase with cold anomalies of SST. However, the negative SST anomalies in the tropical Indian Ocean are less impactful on SIF anomalies relative to the positive SST anomalies. The observed statistically significant SST–SIF link is feasible through atmospheric teleconnections. During monsoon onset, positive SST anomalies in the tropical Indian Ocean favour weakened monsoon flow, decreasing moisture transport from the ocean to the Indian mainland. The resultant water deficiency, along with the high air temperature, created a stress condition and reduced the photosynthetic rate, thus demonstrating negative SIF anomalies across India. Conversely, negative SST anomalies strengthened monsoon winds in the onset period and increased moisture availability across India. Negative air temperature anomalies also dampen water stress conditions and increased photosynthetic activity, resulting in positive SIF anomalies. The identified SST-SIF relationship would be beneficial to generate a simple framework that aids in the detection of the probable impact on vegetation growth across India associated with the rapidly varying climate conditions in the Indian Ocean.
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Chen, Shuling, Jing Cha, Fuwen Qiu, Chunsheng Jing, Yun Qiu, and Jindian Xu. "Sea Surface Salinity Anomaly in the Bay of Bengal during the 2010 Extremely Negative IOD Event." Remote Sensing 14, no. 24 (December 9, 2022): 6242. http://dx.doi.org/10.3390/rs14246242.
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Based on Soil Moisture and Ocean Salinity (SMOS) data and the Ocean Reanalysis System 5 (ORAS5) dataset, positive salinity anomalies exceeding 2 psu in the northern Bay of Bengal (BoB) and negative salinity anomalies with the peak of the freshening anomalies reaching −2 psu around Sri Lanka were observed in autumn 2010. Here, an analysis of the anomalous salt budget revealed that anomalous horizontal advection contributed most to the variability in salinity in the BoB. With the development of La Niña and negative Indian Ocean dipole (nIOD) in summer and autumn, the strong summer monsoon current and Wyrtki jet combined with the anomalous basin-scale cyclonic circulation led to more high-salinity water entering the northern BoB. In addition, more freshwater was transported southward along the eastern coast of India by east Indian coastal current (EICC) in autumn, resulting in extremely negative salinity anomalies around Sri Lanka and positive salinity anomalies in the northern BoB. Moreover, the freshwater around Sri Lanka was carried farther into the southeastern Arabian Sea by the west Indian coastal current (WICC) in November, which affected the salinity stratification in winter and then influenced the variation of the Arabian Sea Mini Warm Pool (ASMWP) in the following spring. The ASMWP could affect the Indian summer monsoon (ISM) through its influence on the monsoon onset vortex (MOV) over the southeast Arabian Sea (SEAS).
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Zhao, Yu, Anmin Duan, Guoxiong Wu, and Ruizao Sun. "Response of the Indian Ocean to the Tibetan Plateau Thermal Forcing in Late Spring." Journal of Climate 32, no. 20 (September 16, 2019): 6917–38. http://dx.doi.org/10.1175/jcli-d-18-0880.1.
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Abstract The thermal effect of the Tibetan Plateau (TP) is known to exert substantial impacts on the atmospheric general circulation, suggesting that it may also influence the wind-driven circulation in the ocean through air–sea interactions. Here, several coupled general circulation model experiments are performed in order to investigate the short-term response of the Indian Ocean to the TP surface heat source in late spring (May). The results indicate that positive TP heating anomalies can induce significant atmospheric circulation responses over the northern Indian Ocean, characterized by easterly anomalies in the upper troposphere due to the enhanced South Asian high and lower-level southwesterly anomalies from the heat pumping effect. As a result, the surface wind speed over the northern Indian Ocean is reinforced, leading to intensified oceanic evaporation and subsequently cooler potential temperatures in the mixed layer. Wind-driven currents in the mixed layer are also affected. In the Bay of Bengal, Ekman transport facilitates water volume movement from west to east. In the Arabian Sea, water movement is weaker and the southward component is relatively more important. Both these areas show local meridional circulations with offshore upwelling in the northwest. Moreover, the cross-equatorial current is also enhanced in the eastern part of the tropical Indian Ocean. Overall, the upper layer in the northern Indian Ocean is efficiently modulated by the TP thermal forcing within one month.
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Mishukova, G. I., A. V. Yatsuk, and R. B. Shakirov. "Distribution of methane fluxes on the water–atmosphere interface in different regions of the World Ocean." Geosystems of Transition Zones 5, no. 3 (2021): 240–54. http://dx.doi.org/10.30730/gtrz.2021.5.3.240-247.247-254.
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For the first time, methane fluxes at the water-atmosphere interface were calculated for the water area of Pacific, Indian, and Atlantic oceans (for the area about 30,000 miles) on the basis of the expeditionary measurements of methane concentrations in the surface layer of water and subsurface layer of the atmosphere along the entire course of the vessel. Methane fluxes at the water-atmosphere interface were calculated for the water areas of the Pacific, Indian and Atlantic oceans. In the result of the studies carried out in various regions of the World Ocean, an uneven spatial distribution of methane fluxes from strong absorption to emission of anomalous intensity was observed. The article presents the results of a detailed study for the deepwater area of the Indian Ocean open waters in the northern part of the Ninetyeast Ridge. Both supersaturation and undersaturation of seawater respectively to its concentrations in the atmosphere have been revealed on the basis of the direct measurements of methane concentrations in the ocean surface water layer. The distribution of dissolved methane in the water column of the Indian Ocean has been considered.
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Rae, James W. B., and Wally Broecker. "What fraction of the Pacific and Indian oceans' deep water is formed in the Southern Ocean?" Biogeosciences 15, no. 12 (June 21, 2018): 3779–94. http://dx.doi.org/10.5194/bg-15-3779-2018.
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Abstract. In this contribution we explore constraints on the fractions of deep water present in the Indian and Pacific oceans which originated in the northern Atlantic and in the Southern Ocean. Based on PO4* we show that if ventilated Antarctic shelf waters characterize the Southern contribution, then the proportions could be close to 50–50. If instead a Southern Ocean bottom water value is used, the Southern contribution is increased to 75 %. While this larger estimate may best characterize the volume of water entering the Indo-Pacific from the Southern Ocean, it contains a significant portion of entrained northern water. We also note that ventilation may be highly tracer dependent: for instance Southern Ocean waters may contribute only 35 % of the deep radiocarbon budget, even if their volumetric contribution is 75 %. In our estimation, the most promising approaches involve using CFC-11 to constrain the amount of deep water formed in the Southern Ocean. Finally, we highlight the broad utility of PO4* as a tracer of deep water masses, including descending plumes of Antarctic Bottom Water and large-scale patterns of deep ocean mixing, and as a tracer of the efficiency of the biological pump.
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Krishna, Moturi S., Rongali Viswanadham, Mamidala H. K. Prasad, Vuravakonda R. Kumari, and Vedula V. S. S. Sarma. "Export fluxes of dissolved inorganic carbon to the northern Indian Ocean from the Indian monsoonal rivers." Biogeosciences 16, no. 2 (January 30, 2019): 505–19. http://dx.doi.org/10.5194/bg-16-505-2019.
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Abstract. Rivers are an important source of dissolved inorganic carbon (DIC) to the adjacent coastal waters. In order to examine the spatial variability in the distribution and major sources of DIC in the Indian monsoonal rivers and to quantify their export flux to the northern Indian Ocean, 27 major and medium-sized rivers were sampled during the discharge period. Significant spatial variability in concentrations of DIC (3.4–73.6 mg L−1) was observed, and it is attributed to spatial variations in the precipitation pattern, the size of rivers, pollution and lithology of the catchments. The stable isotopic composition of DIC (δ13CDIC) also showed strong spatial variability (−13.0 ‰ to −1.4 ‰) in the Indian monsoonal rivers with relatively depleted δ13CDIC values in rivers of the northwest of India (-11.1±2.3 ‰) and enriched values in the southeast of India (-3.5±2.3 ‰). Results of the linear least-squares regression models of Keeling and Miller–Tan's plots indicated that the chemical weathering of carbonate and silicate minerals by soil CO2 is the major source of DIC in the Indian monsoonal rivers. Spatial variability in the deviation of δ13CDIC from the approximated δ13C of the source may probably be due to dominant autotrophic production in rivers of the southeastern region, whereas heterotrophic decomposition of organic matter largely influences the other Indian monsoonal rivers. It is estimated that the Indian monsoonal rivers annually export ∼10.3 Tg of DIC to the northern Indian Ocean, of which the major fraction (75 %) enters into the Bay of Bengal, and the remaining fraction reaches to the Arabian Sea. This is consistent with the freshwater flux, which is 3 times higher for the Bay of Bengal (∼378 km3 yr−1) than for the Arabian Sea (122 km3 yr−1). Despite discharge from the Indian monsoonal rivers accounting for only 1.3 % of the global freshwater discharge, they disproportionately export 2.5 % of the total DIC exported by the world's major rivers. Despite rivers from the region in the southwest (SW) of India exporting DIC that is an order of magnitude lower (0.3 Tg yr−1) than the rivers from other regions of India, the highest yield of DIC was found in the rivers of the SW region of India. It is attributed to intense precipitation (∼3000 mm), favorable natural vegetation of tropical moist deciduous and tropical wet evergreen and semi-evergreen forests, tropical wet climate, high soil organic carbon, and the dominance of red loamy soils in catchments of the rivers of the SW region.
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KHALAJI-PIRBALOUTY, VALIALLAH, and JOHANN-WOLFGANG WÄGELE. "A new record of Sphaeroma annandalei Stebbing, 1911 (Crustacea: Isopoda: Sphaeromatidae) from the Persian Gulf, and description of a new related species (Sphaeroma silvai nov. sp.) from the South Atlantic Ocean." Zootaxa 2508, no. 1 (June 16, 2010): 30. http://dx.doi.org/10.11646/zootaxa.2508.1.2.
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Two similar species of Sphaeroma (Sphaeromatidae: Isopoda) are studied and described from two different Oceans. Sphaeroma annandalei Stebbing, 1911 is redescribed from different localities of the Indian Ocean, and Sphaeroma silvai sp. nov. is described from the South Atlantic Ocean. Sphaeroma silvai sp. nov. is easily distinguished from S. annandalei by its pereopod 5, where the basis carries a well extended inferior lobe; the shape of the pleotelson and the tuberculation of pereonites and pleon. Both species are distinguished from other species of the genus by transverse ridges on their pereonites. The known distribution of S. annandalei is limited to the northern areas of the Indian Ocean, from the Persian Gulf to Malaysia.
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Srivastava, D. K., Alok Dave, and V. Dangwal. "Sequence stratigraphy of the Andaman Basin, northern Indian Ocean." Marine and Petroleum Geology 133 (November 2021): 105298. http://dx.doi.org/10.1016/j.marpetgeo.2021.105298.
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Raj, Harsh, Ravi Bhushan, Sanjeev Kumar, Upasana S. Banerji, Chinmay Shah, and Sangeeta Verma. "Monsoon signature in corals from the northern Indian Ocean." Journal of Marine Systems 226 (February 2022): 103664. http://dx.doi.org/10.1016/j.jmarsys.2021.103664.
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Delaygue, Gilles, Edouard Bard, Claire Rollion, Jean Jouzel, Michel Stiévenard, Jean-Claude Duplessy, and Gerald Ganssen. "Oxygen isotope/salinity relationship in the northern Indian Ocean." Journal of Geophysical Research: Oceans 106, no. C3 (March 15, 2001): 4565–74. http://dx.doi.org/10.1029/1999jc000061.
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Pollehne, Falk, Bernt Zeitzschel, and Rolf Peinert. "Short-term sedimentation patterns in the northern Indian Ocean." Deep Sea Research Part II: Topical Studies in Oceanography 40, no. 3 (January 1993): 821–31. http://dx.doi.org/10.1016/0967-0645(93)90060-z.
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Hoarau, Karl, Julien Bernard, and Ludovic Chalonge. "Intense tropical cyclone activities in the northern Indian Ocean." International Journal of Climatology 32, no. 13 (August 15, 2011): 1935–45. http://dx.doi.org/10.1002/joc.2406.
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Rafique, Muhammad Umair, and Sayed Amir Hussain Shah. "Environmental Degradation in Indian Ocean." Progressive Research Journal of Arts & Humanities (PRJAH) 1, no. 01 (March 3, 2021): 16–27. http://dx.doi.org/10.51872/prjah.vol1.iss01.12.
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Indian Ocean is the third largest ocean in the world spanning over an area of 73,556,000 Square. kilometers, that covers three continents, Africa, Asia, and Australia. Pakistan is an emerging strategic and geopolitical significant state of the South Asia; it has 1046 kilometers of coastline across the Arabian Sea, a region of Northern Indian Ocean. The country’s largest province ‘Baluchistan’ possesses 800 kilometers of coastline, whereas remaining 246 kilometers is in ‘Sindh’ province. The level of marine pollution is extremely high in Karachi, an economic hub and populous port city of the Sindh. The Karachi Port harbour area is full of toxic pollutants until they are evaporated or settle down at the bottom. The objective of this paper is to highlight the dilemma of marine pollution in Pakistan's coastline especially in the port city of Karachi. The study is aimed to provide remedial measures to preserve endanger rare marine species of Pakistan’s territorial waters. The paper will also provide an empirical and theoretical overview of coastal governance in Pakistan.
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Anderson, Charles, Isha, Dipani Sutaria, and Asha De Vos. "note on humpback whales (Megaptera novaeangliae) in the central Indian Ocean." J. Cetacean Res. Manage. 23, no. 1 (July 20, 2022): 49–57. http://dx.doi.org/10.47536/jcrm.v23i1.341.
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In the central Indian Ocean, humpback whales (Megaptera novaeangliae) are rare. Records from southern India, Sri Lanka, Maldives and the Chagos Archipelago (n=67) were compiled and show a bimodal pattern of seasonal occurrence. Those occurring during the northern winter (December to April) are known to belong to the Arabian Sea humpback whale population. There have been no humpback whales recorded in Maldives during the northern winter since 2001, suggesting a possible range contraction for the Arabian Sea humpback whale population. Humpback whales occurring during the southern winter (June to October) are assumed to belong to the southwest Indian Ocean population (IWC breeding stock C). In this case, numbers of opportunistic sightings are increasing and the population appears to be spreading northwards as it recovers from commercial whaling, with several recent southern winter records from as far north as 5°N in northern Maldives and southern Sri Lanka. For this southern hemisphere population, calves are first seen in August, with numbers of calves increasing in September and October. For both populations, interactions with regional fisheries, particularly pelagic gillnetting, may be a major cause of mortality.
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Reid, Anthony. "The Indian Dimension of Aceh and Sumatra History." Journal of Maritime Studies and National Integration 4, no. 2 (December 24, 2020): 64–72. http://dx.doi.org/10.14710/jmsni.v4i2.8639.
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Indonesia’s maritime boundary with India, lying barely 100km from Banda Aceh, appears quiet and of little interest to policy-makers, in contrast to almost all the other contested boundaries with Malaysia, China, the Philippines, and Australia. India’s historical relations with Sumatra have also drawn less scholarly or popular attention than those with the Arab, Persian, and Turkish worlds, or with Java, the Peninsula, and China. It is one of the imbalances and justifying the “Indian Ocean’ in the title of International Centre for Aceh and Indian Ocean Studies. It is also supported by arguing that northern Sumatra’s most important historical relationship outside Sumatra itself was for long with India. The time must come when this neighbourly maritime relationship is normalised in the context of improving Indonesia-India ties.
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Li, Shuanglin, Judith Perlwitz, Martin P. Hoerling, and Xiaoting Chen. "Opposite Annular Responses of the Northern and Southern Hemispheres to Indian Ocean Warming." Journal of Climate 23, no. 13 (July 1, 2010): 3720–38. http://dx.doi.org/10.1175/2010jcli3410.1.
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Abstract Atmospheric circulation changes during boreal winter of the second half of the twentieth century exhibit a trend toward the positive polarity of both the Northern Hemisphere annular mode (NAM) and the Southern Hemisphere annular mode (SAM). This has occurred in concert with other trends in the climate system, most notably a warming of the Indian Ocean. This study explores whether the tropical Indian Ocean warming played a role in forcing these annular trends. Five different atmospheric general circulation models (AGCMs) are forced with an idealized, transient warming of Indian Ocean sea surface temperature anomalies (SSTA); the results of this indicate that the warming contributed to the annular trend in the NH but offset the annular trend in SH. The latter result implies that the Indian Ocean warming may have partly cancelled the influence of the stratospheric ozone depletion over the southern polar area, which itself forced a trend toward the positive phase of the SAM. Diagnosis of the physical mechanisms for the annular responses indicates that the direct impact of the diabatic heating induced by the Indian Ocean warming does not account for the annular response in the extratropics. Instead, interactions between the forced stationary wave anomalies and transient eddies is key for the formation of annular structures.
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Wang, Shuguang, Juan Fang, Xiaodong Tang, and Zhe-Min Tan. "A Survey of Statistical Relationships between Tropical Cyclone Genesis and Convectively Coupled Equatorial Rossby Waves." Advances in Atmospheric Sciences 39, no. 5 (January 6, 2022): 747–62. http://dx.doi.org/10.1007/s00376-021-1089-8.
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AbstractConvectively coupled equatorial Rossby waves (ERW) modulate tropical cyclone activities over tropical oceans. This study presents a survey of the statistical relationship between intraseasonal ERWs and tropical cyclone genesis (TCG) over major global TC basins using four-decade-long outgoing longwave radiation (OLR) and TC best-track datasets. Intraseasonal ERWs are identified from the OLR anomalies using an empirical orthogonal function (EOF) analysis method without imposing equatorial symmetry. We find that westward-propagating ERWs are most significant in four tropical ocean basins over the summer hemisphere and that ERWs exhibit similar northeast-southwest (southeast-northwest) tilted phase lines in the northern (southern) hemisphere, with an appreciable poleward advance of wave energy in most TC basins. The EOF-based ERW indices quantitatively show that ERWs significantly modulate TC genesis. The convectively active (suppressed) phases of ERWs coincide with increased (reduced) TCG occurrences. The TCG modulation by ERWs achieves the maximum where the ERWs propagate through the climatological TCG hotspots. As a result, the total number of TCG occurrences in the TC basins varies significantly according to the ERW phase. The ERW-TCG relationship is significant over the northwestern Pacific Ocean, northeastern Pacific Ocean, and the northern Indian Ocean during the northern summer seasons. In the southern summer season, the ERW-TCG relationship is significant over the southern Indian Ocean, Indonesian-Australia basin, and the southwestern Pacific Ocean. However, ERW activities are weak in the main TC development region of the Atlantic Ocean; and the impact on Atlantic TCG appears to be insignificant.
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Saraswat, Rajeev, Thejasino Suokhrie, Dinesh K. Naik, Dharmendra P. Singh, Syed M. Saalim, Mohd Salman, Gavendra Kumar, et al. "Large freshwater-influx-induced salinity gradient and diagenetic changes in the northern Indian Ocean dominate the stable oxygen isotopic variation in Globigerinoides ruber." Earth System Science Data 15, no. 1 (January 10, 2023): 171–87. http://dx.doi.org/10.5194/essd-15-171-2023.
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Abstract. The application of stable oxygen isotopic ratio of surface-dwelling planktic foraminifera Globigerinoides ruber (white variety; δ18Oruber) to reconstruct past hydrological changes requires a precise understanding of the effect of ambient parameters on δ18Oruber. The northern Indian Ocean, with its huge freshwater influx and being a part of the Indo-Pacific Warm Pool, provides a unique setting to understand the effect of both the freshwater-influx-induced salinity and temperature on δ18Oruber. Here, we use a total of 400 surface samples (252 from this work and 148 from previous studies), covering the entire salinity end-member region, to assess the effect of freshwater-influx-induced seawater salinity and temperature on δ18Oruber in the northern Indian Ocean. The analysed surface δ18Oruber mimics the expected δ18O calcite estimated from the modern seawater parameters (temperature, salinity, and seawater δ18O) very well. We report a large diagenetic overprinting of δ18Oruber in the surface sediments, with an increase of 0.18 ‰ per kilometre increase in water depth. The freshwater-influx-induced salinity exerts the major control on δ18Oruber (R2=0.63) in the northern Indian Ocean, with an increase of 0.29 ‰ per unit increase in salinity. The relationship between temperature- and salinity-corrected δ18Oruber (δ18Oruber−δ18Osw) in the northern Indian Ocean [T=-0.59⋅(δ18Oruber-δ18Osw)+26.40] is different than reported previously, based on the global compilation of plankton tow δ18Oruber data. The revised equations will help create a better palaeoclimatic reconstruction from the northern Indian Ocean by using the stable oxygen isotopic ratio. The entire data set (newly generated and previously published) used in this work is available both as a Supplement to this article and at PANGAEA (https://doi.org/10.1594/PANGAEA.945401; Saraswat et al., 2022).
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Smirnov, A., B. N. Holben, D. M. Giles, I. Slutsker, N. T. O'Neill, T. F. Eck, A. Macke, et al. "Maritime Aerosol Network as a component of AERONET – first results and comparison with global aerosol models and satellite retrievals." Atmospheric Measurement Techniques Discussions 4, no. 1 (January 8, 2011): 1–32. http://dx.doi.org/10.5194/amtd-4-1-2011.
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Abstract. The Maritime Aerosol Network (MAN) has been collecting data over the oceans since November 2006. Over 80 cruises were completed through early 2010 with deployments continuing. Measurements areas included various parts of the Atlantic Ocean, the Northern and Southern Pacific Ocean, the South Indian Ocean, the Southern Ocean, the Arctic Ocean and inland seas. MAN deploys Microtops hand-held sunphotometers and utilizes a calibration procedure and data processing traceable to AERONET. Data collection included areas that previously had no aerosol optical depth (AOD) coverage at all, particularly vast areas of the Southern Ocean. The MAN data archive provides a valuable resource for aerosol studies in maritime environments. In the current paper we present results of AOD measurements over the oceans, and make a comparison with satellite AOD retrievals and model simulations.
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Smirnov, A., B. N. Holben, D. M. Giles, I. Slutsker, N. T. O'Neill, T. F. Eck, A. Macke, et al. "Maritime aerosol network as a component of AERONET – first results and comparison with global aerosol models and satellite retrievals." Atmospheric Measurement Techniques 4, no. 3 (March 21, 2011): 583–97. http://dx.doi.org/10.5194/amt-4-583-2011.
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Abstract. The Maritime Aerosol Network (MAN) has been collecting data over the oceans since November 2006. Over 80 cruises were completed through early 2010 with deployments continuing. Measurement areas included various parts of the Atlantic Ocean, the Northern and Southern Pacific Ocean, the South Indian Ocean, the Southern Ocean, the Arctic Ocean and inland seas. MAN deploys Microtops hand-held sunphotometers and utilizes a calibration procedure and data processing traceable to AERONET. Data collection included areas that previously had no aerosol optical depth (AOD) coverage at all, particularly vast areas of the Southern Ocean. The MAN data archive provides a valuable resource for aerosol studies in maritime environments. In the current paper we present results of AOD measurements over the oceans, and make a comparison with satellite AOD retrievals and model simulations.
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Putra, I. Nyoman Januarta Triska, I. Wayan Gede Astawa Karang, and I. Dewa Nyoman Nurweda Putra. "Analisis Temporal Suhu Permukaan Laut di Perairan Indonesia Selama 32 Tahun (Era AVHRR)." Journal of Marine and Aquatic Sciences 5, no. 2 (August 5, 2019): 234. http://dx.doi.org/10.24843/jmas.2019.v05.i02.p11.
Full textAbstract:
One of the important factor that influences global climate dynamics is sea surface temperature (SST). Indonesian waters are semi-closed and located between the Pacific and Indian Oceans so that they have different characteristics of SPL in each region. The purpose of this research is to know the trend and local characteristics of Indonesian SST and adjacent areas in response to 6-monthly and seasonal variability with moving average method and correlation. The data used are SST data from AVHRR satellite with domain 15°N-15°S, 90°-145° E. The results showed of increase trend 0.34°C in Indonesian sea for 32 years (1981-2012). The characteristics of SST in Indonesian territory are closely related to the Mosoon cycle where in the East period in the northern region the Natuna Sea is warmer in contrast to the West monsoon period, in the southern part of the Arafura Sea to the warmer Sawu Sea and around the equator experiencing the warmest in the transitional period. The moving-average analysis shows that 6-monthly variability appears to be dominated in equatorial waters including the Java Sea and Banda Sea whereas seasonal variability occurs in the northern and southern regions of Indonesia's waters including the Pacific Ocean Oceans, the northwest Pacific Ocean and the southeast Indian Ocean. Based on correlation analysis, ENSO has a strong (negative) relationship in eastern Indonesia waters including the Sea in the northern part of Papua and the northwest Pacific Ocean while IOD has a strong (negative) relationship in the western Sumatra Sea, Banda Sea and Arafura Sea.