• Assessment of NEMO simulated surface current with HF radar along Andhra Pradesh coast

• # Fulltext

https://www.ias.ac.in/article/fulltext/jess/130/0069

• # Keywords

HF radar; NEMO; surface currents; southwest monsoon.

• # Abstract

Simulating upper layer of Bay of Bengal through three-dimensional ocean circulation models is a challenging task. In this study, the surface current from the Nucleus European Modelling of Ocean (NEMO) based global ocean assimilation system is assessed against the high frequency (HF) radar data along the Andhra Pradesh coast on a daily scale during southwest monsoon 2016. The temporal variation of NEMO simulated surface current with HF radar data shows that the NEMO model captures the zonal current better than the meridional current. Both NEMO and HF radar show that the mean surface current average over latitude (15.8$^{\circ}$–16.3$^{\circ}$N) is westward for zonal surface current and southward for meridional current with maximum at 40–60 km away from the coast. Further, the monthly mean HF radar derived surface current indicates the strong south-westward flow of surface current dominated during July 2016 with speed more than 50 cm/s which is also well simulated by NEMO analysis. It also captures the cold core eddy during 15–25 July 2016 with very small north-eastward shift with respect to HF radar. The scatter plot of collocated surface zonal and meridional current average over the box (81.5–82.5$^{\circ}$E; 15.5–16.5$^{\circ}$N) clearly shows that NEMO analysis has the correlation of more than 0.5 for both zonal and meridional current.

$\bf{Highlights}$

$\bullet$ The simulation of upper layer of Bay of Bengal (BoB) through three dimensional ocean circulation models is a challenging task. In this study, the surface current from the high resolution NEMO based global ocean assimilation system is compared against the observed High Frequency (HF) radar data along the Andhra Pradesh Coast during the southwest monsoon 2016.

$\bullet$ NEMO analysis captures the mean and variability of surface current very well with HF radar. However, it underestimates the mean surface current which may be due to coarser model resolution and complex non-linear processes in the coastal region.

$\bullet$ The strong cold core eddy during 15–25 July 2016 is observed along the coast which is well simulated in NEMO model with small north-eastward shift with respect to HF radar.

$\bullet$ The scatter plot of collocated surface current from NEMO analysis and HF radar data average over the Andhra Pradesh Coast (APCO; 81.5–82.5$^{\circ}$E; 15.5–16.5$^{\circ}$N) clearly shows that NEMO analysis has the correlation of more than 0.5 for surface current.

• # Author Affiliations

1. National Centre for Medium Range Weather Forecasting, Ministry of Earth Sciences, Noida, UP 201 309, India.
2. Department of Geophysics, Banaras Hindu University, Varanasi, UP, India.

• # Journal of Earth System Science

Volume 130, 2021
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019