Onset and Evolution of Upwelling along the West Coast of India

To describe the onset and evolution of upwelling along the south west coast of India, authors collected a series of conductivity temperature depth measurements on board INS Sagardhwani extending from 7 °N – 15 °N during the period extending from February 2017 - October 2017. In this paper we utilised the undulations of the 23 °C isotherm as a proxy to study the upwelling phenomenon. The upward movement of the waters at the southern tip off India (77.5 °E) in the subsurface levels was observed to commence from late February 2017 in depths around 80 m and by the end of May 2017, it is observed to rise rapidly to the surface. The upwelled waters reach the surface during the 2nd week of July all along the Indian coast, and then intensified during August 2017. Beyond 12 °N maximum upwelling is seen in July and thereafter in early August 2017 upwelling was intense till October 2017

Observed Inter annual Variability of Upwelling Characteristics during 2016 2017 A Study using Princeton Ocean Model

Oceanographic observations carried out during 2016 and 2017 onboard INS Sagardhwani in the Southeastern Arabian sea are used to study the inter-annual variability of the upwelling. In 2016, the strong upwelling signatures are noticed in the observations (SST < 27°C and strong up-slopping of isotherms) as well as in the satellite derived sea level anomaly data. Whereas in 2017 the low sea level in June (-2 cm) are weakened during the mid of July (+3 cm) along the southern track (8 °N and 9 °N). This decrease in the strength in 2017 can be attributed to two major reasons. One is the presence of an anti-cyclonic eddy along the coast (8.5 °N, 76.5 °E) weakens the upwelling processes and second is the weak northerly component of the wind compared to 2016. In addition, Lakshadweep low is less prominent and situated towards the southern side (around 7°N) of its usual region of occurrence in 2017. The inter-annual variability of upwelling during July 2016 and 2017 is investigated using the 3D ocean model Princeton Ocean Model. Experiments with model in different combinations of forcing reveals that the alongshore wind component is the major parameter influencing the upwelling characteristics during these periods

Effect of Azimuthal Asymmetry Caused by Upwelling on 3D Ocean Acoustic Propagation

3-D underwater parabolic equation model based on implicit finite difference method has been implemented for South Eastern Arabian Sea (SEAS). The bathymetric and geo-acoustic features have been integrated in the model for a 50 km circular region in SEAS. The model can simulate the effects of azimuthal variation in oceanographic features and compute azimuthally coupled pressure due to an omni-directional source. The azimuthal variation in oceanographic conditions can be observed during an upwelling event. In the first case study, the effect of upwelling event on three-dimensional acoustic propagation has been studied by using sound speed profile data derived from INS Sagardhwani observations. The difference in Transmission loss mosaic for upslope and downslope propagation is due to bathymetry as well as upwelling. In the second case study, the effect of upwelling only, is studied by running a model corresponding to range independent sound speed profile field and range dependent bathymetry. It was observed that during this upwelling event, the transmission loss is higher at longer ranges during upslope propagation than downslope propagation. This is due to the increase in the thickness of sonic layer duct as acoustic wave propagates from shallow to deep water. The effect of azimuthal variation

Formulation of an Empirical Relation between Chlorophyll and Sea Surface Temperature in the Southeastern Arabian Sea

Present study formulates an empirical relation between sea surface temperature (SST) and chlorophyll (Chl) in the Southeastern Arabian Sea using data collected during 2017. SST was found to decrease due to upwelling of cold nutrient rich waters, thus causing enhancement of Chl in the coastal and nearshore waters. Based on this, an empirical relationship exists which is inversely correlated during peak upwelling and intense biological production. The linear regression generated a significant correlation coefficient (0.52 ≤ R2 ≥ 0.64) in the month of July, August and October. Although other factors influence Chl, SST can be considered as a significant indicator of biological production with respect to seasonal upwelling. Among the empirical relations, a definite single equation requires the assessment of subsurface Chl to reveal the underlying relationship

Development of a simple enzyme-linked immunosorbent assay for quantitative estimation of aflatoxin B1 albumin adduct in humans

In the present study, high titred polyclonal antibodies were produced against synthetic AFB1-lys and developed a simple indirect competitive (IC)-ELISA for quantitative estimation of AFB1-lys adducts in human serum albumin. IC-ELISA was validated by testing 250 blood samples that include 85 HBV positive samples from unidentified subjects from the Apollo Health City, Hyderabad, and 165 blood samples collected from ICRISAT campus, Hyderabad, India. All the samples that were positive to AFB1-lys were from HBV-positive subjects, indicating a potential risk of hepatocellular carcinoma in 4.8% of the subjects tested in the present study. This validation confirms the suitability of IC-ELISA, which is simple, cost-effective and enables high-throughput analysi