The U.S. Department of Energy has integrated an ASSIST II system into the ARM Mobile Facility 2.  The current AMF2 deployement is a six month mission on Gan Island in the Maldives from October 2011 through March 2012 in support of the ARM MJO Investigation Experiment AMIE).  This mission, in conjunction with the international CINDY2011 campaign is designed to test current hypotheses regarding the underlying mechanisms responsible for the Madden-Julian Oscillation (MJO) development in the Indian Ocean. 

 

Deep convection in the tropics plays an important role in driving global circulations and the transport of energy from the tropics to the mid-latitudes. Understanding the mechanisms that control tropical convection is a key to improving climate modeling simulations of the global energy balance. 

 

The MJO dominates tropical intraseasonal variability and has important interactions with the monsoon and El Niño, but there is no agreed upon explanation for the underlying physics that maintain the MJO. Although the MJO is readily observable with a period of approximately 30-60 days, climate models nonetheless have difficulty predicting and accurately describing it.

 

Many climate models do not show well-defined MJO signals, and even those that successfully exhibit the oscillation have problems accurately simulating the amplitude, propagation speed, and/or seasonality of the MJO signal. Therefore, the MJO is a very important modeling target for the ARM modeling community geared specifically toward improving climate models. 

 

The ASSIST II is listed as a critical instrument for this ARM campaign and will be vital to establishing radiative closure and for helping to define the thermodynamic profile of the atmosphere, especially water vapor and temperature.