Estimating water levels caused by a tropical storm along the Bangladesh coast: A numerical approach

Gour Chandra Paul; Irfan Raju; Md Zakir Hossain; Tauhida; Md Nuruzzaman; Mst Rupale Khatun; Md Emran Ali

doi:10.1016/j.heliyon.2023.e19901

Estimating water levels caused by a tropical storm along the Bangladesh coast: A numerical approach

Heliyon. 2023 Sep 7;9(10):e19901. doi: 10.1016/j.heliyon.2023.e19901. eCollection 2023 Oct.

Authors

Gour Chandra Paul¹, Irfan Raju², Md Zakir Hossain³, Tauhida⁴, Md Nuruzzaman⁵, Mst Rupale Khatun^{1

5}, Md Emran Ali^{1

6}

Affiliations

¹ Department of Mathematics, University of Rajshahi, Rajshahi, 6205, Bangladesh.
² Department of Arts and Sciences, Bangladesh Army University of Science and Technology, Saidpur Cantonment, Saidpur 5310, Bangladesh.
³ Department of Basic Sciences and Humanities, University of Asia Pacific, Dhaka, 1205, Bangladesh.
⁴ Department of Computer Science Engineering, Northern University Bangladesh, Dhaka, 1230, Bangladesh.
⁵ Department of Mathematics, Rajshahi University of Engineering & Technology, Rajshahi, 6204, Bangladesh.
⁶ Department of Textile Engineering, Northern University Bangladesh, Dhaka, 1230, Bangladesh.

Abstract

In this study, water levels resulting from the dynamic interaction of tide and surge are estimated by solving a 2-D vertically integrated shallow water equations numerically. To solve the equations on the specific 2-D grid, the explicit Leapfrog scheme is implemented, adopting a staggered Arakawa C-grid. The domain's complex land-sea interface is approximated through the stair-step method in order to employ the finite difference technique. To incorporate the complexity of the domain with a considerably high accuracy and to reduce computational cost, one-way nested grid models are embraced. The Meghna River freshwater discharge is incorporated into the innermost child model. A stable tidal regime over the region of interest is generated by applying the four vital tidal constituents, namely $M_{2}$ (principal lunar semidiurnal), $S_{2}$ (principal solar semidiurnal), $O_{1}$ (principal lunar diurnal) and $K_{1}$ (luni-solar diurnal) in the southern open boundary of the outermost model. This previously effectuated tidal regime is used as the initial state of the sea in getting total water levels due to the dynamic interaction of tide and surge. Numerical experiments are performed with the storm AILA that hit the coast of Bangladesh on May 25, 2009. The simulated results are found to closely match observed and reported data.

Keywords: AILA; Leapfrog scheme; Nested scheme; Shallow water equations.