Sumida, Tokyo International schools: Sumida maintains sister-city relationships with Seodaemun-gu, Seoul, South Korea, and with Shijingshan District, Beijing, China. 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
Arakawa grids Arakawa grids The Arakawa grid system depicts different ways to represent and compute orthogonal physical quantities (especially velocity- and mass-related quantities) on rectangular grids used for Earth system models for meteorology and oceanography. For example, the Weather Research and Forecasting Model uses the Arakawa Staggered C-Grid in its atmospheric calculations when using the ARW core. The five Arakawa grids (A-E) were first introduced in Arakawa and Lamb 1977. For an image of the five grids, see the following picture, or Fig. 1 in Purser and Leslie 1988. The "unstaggered" Arakawa A-grid evaluates all quantities at the same point on each