The Global Sea Level Observing System (GLOSS) is a network of tide gauges around the world that was established to monitor the global sea level change. Over 70 countries participate in this network. Sea level data is useful for coastal protection during events such as storm surges; providing flood warning and monitoring tsunamis; tide tables for port operations, fishermen, and recreation; and research into sea level change and ocean circulation. The core stations (~300) of GLOSS are shown below with their active status.