The large-scale forcing data for the ARM MJO Investigation Experiment (AMIE) on Gan Island in the Maldives are now available for use and evaluation by the cloud modeling community. AMIE-Gan was conducted during the period October 2011 to March 2012 in conjunction with the Dynamics of the Madden-Julian Oscillation (DYNAMO) and Cooperative Indian Ocean experiment on intraseasonal variability in the Year 2011 (CINDY2011) campaigns. The goal of AMIE-Gan is to collect necessary data for studies of the initiation, propagation, and evolution of MJO and the associated convective clouds.

Due to the lack of a sounding array at Gan Island, the forcing data for AMIE-Gan was developed based on European Centre for Medium-Range Weather Forecasts (ECMWF) analyses, which were then constrained with observed surface rainfall through the constrained variational objective analysis approach described in Zhang and Lin 1997, Zhang et al. 2001, and Xie et al. 2004. Three versions of the forcing data are provided, which were constrained by surface precipitation retrieved from SMART-R, S-POL, and TRMM precipitation radar measurements, respectively, to address uncertainties in surface rainfall. Currently, the forcing data cover the period from 11/13/2011 to 12/13/2011, which contained the second major MJO observed during the DYNAMO-AMIE period. The forcing data represent an average over the analysis domain of about 150 km radius centered at Gan Island, comparable to the SMART-R precipitation radar coverage. The data are available in both ASCII and netCDF formats.

As always, feedback and use of the data are welcomed and encouraged. For questions, or to report data problems, please contact Shaocheng Xie, Renata McCoy, or Yunyan Zhang.

To access the AMIE-Gan forcing data set, log into the ARM Data Archive. (Go here to request an account).