A General View of the International Field Experiment CINDY2011 and DYNAMO

The Madden-Julian Oscillation or MJO is known as the dominant intraseasonal mode in the tropics, which has a great impact onto the global climate. In spite of its crucial role in the global climate system, a lack of enough in-situ data in the Indian Ocean, where most MJO-convections appear first, makes difficult to understand the initiation mechanism of the MJO. This situation results in the poor simulation and prediction of the MJO by numerical models. To meet this scientific necessity, an international field experiment “Cooperative Indian Ocean experiment on intraseasonal variability in the Year 2011 (CINDY2011)” has been conducted. In particular, a U.S. project called “Dynamics of the MJO (DYNAMO)”, which is characterized by a tight relationship between observations and numerical studies, plays a central role of this field campaign. Both CINDY2011 and DYNAMO are the endorsed projects by the WCRP/CLIVAR. Besides, U.S. two projects - Atmospheric Radiation Measurement program MJO Investigation Experiment (AMIE) by the Department of Energy, and Littoral Air-Sea Processes experiment (LASP) by the Office of Naval Research - also significantly contribute to the international campaign as inevitable partners. In total, institutes and universities over the ten countries/territories participated in the campaign, including Australia, France, India, Indonesia, Japan, Kenya, Maldives, Papua New Guinea, Seychelles, Singapore, Sri Lanka, Taiwan, U.K. and U.S.

Based on the statistical analyses, observation period and location have been decided to surely capture the intraseasonal variability over the Indian Ocean. The intensive observing period (IOP) has been set to the period from October 2011 through January 2012. In particular, we defined the first two months as a special observing period (SOP) that was designed to resolve the diurnal variation and to study suppressed and/or shallow convection dominant conditions by deploying various radars and by enhancing radiosonde soundings. Furthermore, DYNAMO project continues observations at the Addu Atoll site until the end of March 2012 as an extended observing period in conjunction with AMIE project. During the IOP, we have formed a quadrilateral array for the precise budget analysis with two islands (Gan at 0.7S, 73.2E and Diego Garcia at 7.3S, 72.4E) and two ship-sites at 0, 80.5E and 8S, 80.5E. By considering the seasonal preference of MJO-convection, enhanced soundings at two sites in the northern hemisphere (Male at 4.2N, 73.5E and Colombo at 6.9N, 80.0E) have also been conducted during the SOP. In addition to these special sites, enhanced radiosonde soundings have been carried out at Nairobi and Seychelles as upwind sites, while several radiosonde sites (e.g., Singapore, Indonesia) have provided fine resolution raw data for the campaign. These sounding data have been sent to the meteorological communities immediately after the observation via the global telecommunication system, so that operational centers can use them. As for two ship-sites along the 80E, they were occupied by three ships; R/V Roger Revelle (U.S.), R/V Mirai (Japan), and ORV Sagar Kanya (India). In addition, Indonesian ship Baruna Jaya also joined this campaign to conduct radiosonde sounding over the eastern Indian Ocean along the 8S line.

While various atmospheric measurements have been conducted at sites above mentioned, oceanic observations such as CTD with water sampling, micro-structure profiler, and ADCP, have been conducted on-board the ships. Besides, surface and sub-surface moorings have been deployed along the 78.5E line at 0, 1.5S, 5S, and 10S by the R/V Roger Revelle and Mirai prior to the IOP. A sea-glider and argo floats have also been deployed by these ships. A moored network known as RAMA array, which has been deployed in the Indian Ocean under the guidance of CLIVAR Indian Ocean Panel, also provided basic information on the long-term conditions. During November - December, aircraft observations have also been conducted by U.S. and France groups.

Most of observations have been conducted without severe problems during the campaign. Their status and field report are summarized in the field data catalog provided by the DYNAMO project office (http://www.eol.ucar.edu/projects/dynamo/). It is worth noting that CINDY/DYNAMO data policy regulates that quality controlled data will be open to the public after one-year from the completion of the campaign. Thus, those data will be available from CINDY (http://www.jamstec.go.jp/iorgc/cindy/) and DYNAMO home pages, respectively.

While CINDY/DYNAMO campaign has been conducting, it has already succeeded to capture an MJO event in late October 2011. Some numerical forecasts succeeded in capturing the basic features of convections developed during the IOP. It is highly expected to bring out new knowledge on the MJO from the view points of not only observation analyses but also numerical model studies.