Internal waves in the Andaman Sea 2004

Groups of internal waves form semi-circles as they move across the Andaman Sea in this MODIS image. In oceanographic circles, the Sea is well known for its frequent internal waves. As the name suggests, internal waves are waves that occur inside the ocean. The ocean is divided into layers with dense water on the bottom and light water on top. When the tide pulls the dense lower layer over an obstacle like a ridge or rough area on the ocean floor, a wave is formed. The wave, an internal wave, can move between two ocean layers for days and can stretch tens of kilometers in length. The Andaman Sea has strong semidiurnal tides, tides that have two equal highs and two equal lows per lunar day, that are probably responsible for the frequent waves seen in this region. The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite captured this image on February 25, 2004. Indias Andaman Islands are on the left. In the upper right corner, sediment from Myanmars Ayeyarwady River tint the water green and tan.