Madden-Julian oscillation

Five-day moving averages of normalized MJO indices over a period of 6 months.
The Hovmöller diagram shows the distribution along the lines of longitude horizontally and the development over time from top to bottom; reddish colors mark areas of increased convection, bluish colors areas of suppressed convection.
A movement of the areas to the east can be seen.

The Madden-Julian Oscillation (MJO) , named after Roland Madden and Paul Julian of the National Center for Atmospheric Research , was discovered in 1971 and is a circulating phenomenon of the tropical atmosphere (within 20  degrees of latitude on either side of the equator ) between the Indian Ocean and the central Pacific , which has a 30- to 60-day cycle. This coupled ocean-atmosphere system has a major influence on monsoon variability . There are also influences on theRotation period of the earth known.

The anomalous rainy area appears over the western Ind and remains discernible as it migrates eastward until it reaches the colder waters of the eastern Pacific. It reappears over the tropical Atlantic . The wet phase of the MJO is characterized by increased convection and heavier precipitation , in the subsequent dry phase the thunderstorm activity is suppressed.

See also

• El Niño-Southern Oscillation
• North Atlantic Oscillation
• Pineapple Express
• Quasi-two-year oscillation
• Variability of the period of rotation of the earth

literature

• Michael Sujatta: The Madden-Julian Oscillation . ( Memento from July 16, 2014 in the Internet Archive ) (PDF, 434 kB) Meteorological Seminar University of Hamburg , summer semester 2006.
• Roland A. Madden, Paul R. Julian: Observations of the 40-50-day tropical oscillation - A review . In: Monthly Weather Review , Vol. 122, No. 5, May 1994, pp. 814-837, doi : 10.1175 / 1520-0493 (1994) 122 <0814: OOTDTO> 2.0.CO; 2 .
• Eric Hand: The storm monster. In: Spectrum of Science , May 2016, pp. 70–75.

Individual evidence

1. ^ Daily Madden-Julian Oscillation Indices. National Weather Service , Climate Prediction Center (accessed July 24, 2010).
2. ^ KM Weickmann et al .: The atmospheric angular momentum cycle during the Madden-Julian oscillation. In: Monthly Weather Review. Volume 120, 1992, pp. 2252-2263, doi : 10.1175 / 1520-0493 (1992) 120 <2252: TAAMCD> 2.0.CO; 2 .