Hydrography and water masses in the southeastern Arabian Sea during March-June 2003

This paper describes the hydrographic observations in the southeastern Arabian Sea (SEAS) during two cruises carried out in March-June 2003 as part of the Arabian Sea Monsoon Experiment. The surface hydrography during March-April was dominated by the intrusion of low-salinity waters from the south; during May-June, the low-salinity waters were beginning to be replaced by the high-salinity waters from the north. There was considerable mixing at the bottom of the surface mixed layer, leading to interleaving of low-salinity and high-salinity layers. The flow paths constructed following the spatial patterns of salinity along the sections mimic those inferred from numerical models. Time-series measurements showed the presence of Persian Gulf and Red Sea Waters in the SEAS to be intermittent during both cruises: they appeared and disappeared during both the fortnight-long time series

Interannual variability of surface air-temperature over India: Impact of ENSO and Indian Ocean Sea surface temperature

Interannual variability of the seasonal surface air-temperature over the Indian subcontinent is investigated using observations for the period of 1900–2005. Our results demonstrate that air-temperature over India is remotely influenced by the El Niño-Southern Oscillation and locally through Indian Ocean sea surface temperature (SST) anomalies. The leading mode of variability (EOF-1, empirical orthogonal function) in the observed air-temperature displays a country-wide warming in all four seasons. The spatial pattern of EOF-1 is similar to that of composite air-temperature anomalies of warm/cold years. Above-normal air-temperature in India (country-wide warming) is positively correlated to a simultaneous El Niño conditions in the eastern Pacific during boreal summer. El Niño induced strong subsidence, weaker low-level winds, less moisture availability and enhanced incoming shortwave radiation over the north Indian Ocean and Indian subcontinent are responsible for air-temperature warming in summer. It is observed that during fall, air-temperature pattern of EOF-1 over India is highly correlated with SST over the tropical oceans. SST correlation is maximum in central Pacific and north Indian Ocean, indicating the importance of both remote and local forcing. During boreal spring and winter, air-temperature warming (EOF-1) is mainly influenced by Indian Ocean SST anomalies. Low moisture and negative sea level pressure anomalies over India indicate the existence of heat low with strong dry winds convergence, which are favourable for air-temperature warming in spring. Although El Niño peaks during winter, its impact on the air-temperature over the Indian subcontinent is weak during this season. The second EOF mode shows dipole-like air-temperature pattern with warming over the south-east and cooling in the north-western India during summer and winter, whereas spring shows opposite polarity. In case of boreal fall, EOF-2 of air-temperature displays a south-west and north-east orientation. Mechanisms responsible for these variabilities are studied in detai

Processes of 30-90 days sea surface temperature variability in the northern Indian Ocean during boreal summer

International audienceDuring summer, the northern Indian Ocean exhibits significant atmospheric intraseasonal variability associated with active and break phases of the monsoon in the 30-90 days band. In this paper, we investigate mechanisms of the Sea Surface Temperature (SST) signature of this atmospheric variability, using a combination of observational datasets and Ocean General Circulation Model sensitivity experiments. In addition to the previously-reported intraseasonal SST signature in the Bay of Bengal, observations show clear SST signals in the Arabian Sea related to the active/break cycle of the monsoon. As the atmospheric intraseasonal oscillation moves northward, SST variations appear first at the southern tip of India (day 0), then in the Somali upwelling region (day 10), northern Bay of Bengal (day 19) and finally in the Oman upwelling region (day 23). The Bay of Bengal and Oman signals are most clearly associated with the monsoon active/break index, whereas the relationship with signals near Somali upwelling and the southern tip of India is weaker. In agreement with previous studies, we find that heat flux variations drive most of the intraseasonal SST variability in the Bay of Bengal, both in our model (regression coefficient, 0.9, against ~0.25 for wind stress) and in observations (0.8 regression coefficient); ~60% of the heat flux variation is due do shortwave radiation and ~40% due to latent heat flux. On the other hand, both observations and model results indicate a prominent role of dynamical oceanic processes in the Arabian Sea. Wind-stress variations force about 70-100% of SST intraseasonal variations in the Arabian Sea, through modulation of oceanic processes (entrainment, mixing, Ekman pumping, lateral advection). Our ~100 km resolution model suggests that internal oceanic variability (i.e. eddies) contributes substantially to intraseasonal variability at small-scale in the Somali upwelling region, but does not contribute to large-scale intraseasonal SST variability due to its small spatial scale and random phase relation to the active-break monsoon cycle. The effect of oceanic eddies; however, remains to be explored at a higher spatial resolution

International research in graphene-oxide based materials for net-zero energy, military and aeronautic applications catalysed by Tamaulipas, Mexico: A Mini Review

Graphene oxide, as a nanoscopic platform for functional materials, has been extensively studied for several applications. The present Mini Review stresses the collaborative research in graphene-oxide materials pivoted from the Group of Materials and Technologies for Energy, Health, and Environment at an Instituto Politecnico Nacional unit in Tamaulipas, in Northeastern Mexico, with Mexican, Turkish, and British collaborators. This review covers the recent works on photovoltaic and photocatalytic materials, coatings for thermonuclear reactors, and composites and metamaterials for military and aeronautic applications.</p

International research in graphene-oxide based materials for net-zero energy, military and aeronautic applications catalysed by Tamaulipas, Mexico: a Mini Review

Graphene oxide, as a nanoscopic platform for functional materials, has been extensively studied for several applications. The present Mini Review stresses the collaborative research in graphene-oxide materials pivoted from the Group of Materials and Technologies for Energy, Health, and Environment at an Instituto Politecnico Nacional unit in Tamaulipas, in Northeastern Mexico, with Mexican, Turkish, and British collaborators. This review covers the recent works on photovoltaic and photocatalytic materials, coatings for thermonuclear reactors, and composites and metamaterials for military and aeronautic applications.</p

Hydrography and water masses in the southeastern Arabian Sea during March-June 2003

This paper describes the hydrographic observations in the southeastern Arabian Sea (SEAS) during two cruises carried out in March-June 2003 as part of the Arabian Sea Monsoon Experiment. The surface hydrography during March-April was dominated by the intrusion of low-salinity waters from the south; during May-June, the low-salinity waters were beginning to be replaced by the high-salinity waters from the north.There was considerable mixing at the bottom of the surface mixed layer,leading to interleaving of low-salinity and high-salinity layers, The flow paths constructed following the spatial patterns of salinity along the sections mimic those inferred from numerical models. Time-series measurements showed the presence of Persian Gulf and Red Sea Waters in the SEAS to be intermittent during both cruises: they appeared and disappeared during both the fortnight-long time series