RAMA: The Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction

Michael J. Mcphaden (1) , Gary Meyers , K. Ando , Y. Masumoto , V. S. N. Murty , M. Ravichandran , F. Syamsudin , Jérôme Vialard (2) , Lianbo Yu , W. Yu

1 PMEL - NOAA Pacific Marine Environmental Laboratory [Seattle]
2 LOCEAN - Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques

A new moored buoy array in the historically data-sparse Indian Ocean provides measurements to advance monsoon research and forecasting. The Ocean Research Vessel Sagar Kanya, operated by the Indian Ministry of Earth Sciences, deploys a NOAA ATLAS mooring in the Indian Ocean. (Photo: M. Craig, NOAA) T he Indian Ocean is unique among the three tropical ocean basins in that it is blocked at 25°N by the Asian landmass. Seasonal heating and cooling of the land sets the stage for dramatic monsoon wind reversals and intense seasonal rains over the Indian subcontinent, Southeast Asia, East Africa, and Australia. The Asian landmass also blocks the ocean to the north, so that currents cannot carry heat from the tropics to higher northern latitudes as in the other oceans. Ocean-atmosphere interactions in the region are highly dynamic, involving seasonal current reversals associated with monsoon wind forcing and significant exchanges of heat across the air-sea interface. The Indian Ocean also receives heat from the Pacific via the Indonesian Throughflow (Gordon 2001) while exporting heat to the Atlantic via the Aguhlas Current system (de Ruijter et al. 1999). Monsoon rains occur each year, supporting agricultural production that provides food for a third of the world's population. These rains are irregular, however, leading to years of drought or flood that have significant socioeconomic consequences (Webster et al. 1999). The failure of Indian summer monsoon rains in 2002 (Waple and Larimore 2003) and excessive rains in equatorial East Africa in late 2006 (Arguez 2007) are recent examples of •

The Indian Ocean is unique among the three tropical ocean basins in that it is blocked at 25 degrees N by the Asian landmass. Seasonal heating and cooling of the land sets the stage for dramatic monsoon wind reversals, strong ocean atmosphere interactions, and intense seasonal rains over the Indian subcontinent, Southeast Asia, East Africa, and Australia. Recurrence of these monsoon rains is critical to agricultural production that supports a third of the world's population. The Indian Ocean also remotely influences the evolution of El Nino-Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), North American weather, and hurricane activity. Despite its importance in the regional and global climate system though, the Indian Ocean is the most poorly observed and least well understood of the three tropical oceans. This article describes the Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction (RAMA), a new observational network designed to address outstanding scientific questions related to Indian Ocean variability and the monsoons. RAMA is a multinationally supported element of the Indian Ocean Observing System (IndOOS), a combination of complementary satellite and in situ measurement platforms for climate research and forecasting. The article discusses the scientific rationale, design criteria, and implementation of the array. Initial RAMA data are presented to illustrate how they contribute to improved documentation and understanding of phenomena in the region. Applications of the data for societal benefit are also described.

Domaines: Géophysique [physics.geo-ph]; Géophysique [physics.geo-ph]; Milieux et Changements globaux

Michael J. Mcphaden, Gary Meyers, K. Ando, Y. Masumoto, V. S. N. Murty, et al.. RAMA: The Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction. Bulletin of the American Meteorological Society, 2009, 90, pp.459. ⟨10.1175/2008BAMS2608.1⟩. ⟨hal-00760280⟩