3D Cloud Field Variation Associated with MJO Cycle from the AMIE Field Campaign

Category: Field Campaigns

The Madden-Julian Oscillation (MJO) is an intraseasonal fluctuation in the global tropics with a cycle of 30–60 days (Madden and Julian 1971, 1972). It is characterized by eastward propagation of regions of enhanced and suppressed tropical rainfall, associated with distinct patterns of lower and upper atmospheric circulation anomalies in the tropics. However, the processes responsible for the onset of heavy precipitation and its propagation are still poorly understood. The mechanism by which convection organizes into mesoscale cloud field is little-known. DYNAMO/CINDY2011/AMIE (ARM MJO Investigation Experiment) afford the opportunity to study MJO initiation and evolution.

Deployed multiple wavelength precipitation and cloud radars such as C-POL, SWACR, KAZR, and NCAR S-band dual-polarized (S-Pol) radar and ARM long-term observations at the Manus site offer vertical distribution of cloud fields and allow testing of several of the current hypotheses related to MJO initiation and evolution. We study the convection spectral broadening and heavy precipitation initiation with the composite cloud fields in a function of MJO cycle. These data coupled with simulation studies will provide a basis to improve the representation of the MJO in large-scale climate and weather forecast models.

This poster will be displayed at ASR Science Team Meeting.