A Cloud-Based System for Monitoring Water Quality in Tuul River from Space
Misheel Orgil1*, Bolorchuluun Chogsom1, and Zaya Chinbat2

1Department of Geography, National University of Mongolia, Mongolia
2The united graduate school of Agricultural science, Gifu University, Japan

Abstract

The Tuul River is an essential water source for the water supply and ecological sustainability of Ulaanbaatar. In this study, using Sentinel-2 satellite imagery data from April 21, 2025, the water quality of the Tuul River was assessed using physical parameters such as turbidity, color, and hydrogen ion concentration in accordance with national standards such as MNS ISO 5667:2001, MNS 0900:2018, MNS 4586:2024, and MNS 3900:1986. For this purpose, the Modified Normalized Difference Water Index (MNDWI), the Normalized Difference Turbidity Index (NDTI), which indicate the state of water quality, were calculated. The results of the field survey conducted on April 20, 2025 were compared and verified with the results of physicochemical measurements and analyses taken within the framework of the Water Quality Study of the Tuul River in the Ulaanbaatar City Area project implemented by the Institute of Chemistry and Chemical Technology in 2021. Using the Google Earth Engine platform, it was demonstrated that large amounts of data can be processed over a wide range of space and time, regardless of computer power, and that this methodology can support and in some cases replace field research.

Keywords: Water quality, physical parameters, turbidity, color, hydrogen ion

Topic: Topic B: Applications of Remote Sensing