Sumida, Tokyo Sumida, Tokyo , literally "Ink Field", is a special ward located in Tokyo Metropolis, Japan. The English translation of its Japanese self-designation is Sumida City. As of May 1, 2015, the ward has an estimated population of 257,300, and a population density of 18,690 persons per km². The total area is 13.77 km². Sumida is in the northeastern part of the mainland portion of Tokyo. The Sumida and Arakawa are the major rivers, and form parts of its boundaries. Its neighbors are all special wards: Adachi to the north; Arakawa to the northwest; Katsushika to the east; Edogawa to the
Arakawa grids grid cell, e.g., at the grid center or at the grid corners. The Arakawa A-grid is the only unstaggered grid type. The "staggered" Arakawa B-grid separates the evaluation of the two sets of quantities. e.g., one might evaluate velocities at the grid center and masses at grid corners. The "staggered" Arakawa C-grid further separates evaluation of vector quantities compared to the Arakawa B-grid. e.g., instead of evaluating both east-west (u) and north-south (v) velocity components at the grid center, one might evaluate the u components at the centers of the left and right grid faces, and the v components at