ESSO - Indian National Centre for Ocean Information Services

Overview and Background

The Continental Tropical Convergence Zone (CTCZ) programme is the sequel to the successful Bay of Bengal Monsoon Experiment (BOBMEX) in 1999 and Arabian Sea Monsoon Experiment (ARMEX) in 2002 and 2003 under the Indian Climate Research Programme (ICRP), which was launched in 1996 as a coordinated effort to further our understanding of our climate and improve the prediction skill. The CTCZ programme will focus on understanding the variability of convection/rainfall over the Indian monsoon zone. A major objective of the CTCZ programme is understanding the variability of the large-scale monsoon rainfall associated with space-time variation of the CTCZ on subseasonal and interannual scales, its links with variation of the cloud systems over the oceans surrounding the Indian subcontinent, the role of land-surface-vegetation-atmosphere interactions and the contributions of the interactions between convective systems of cloud scale, meso-scale, and synoptic and planetary scales.

Under the CTCZ programme, special efforts will be made to elucidate the nature of the cloud systems over land and measure critical components of water and heat balance in selected basins/watersheds to understand the impact of land surface processes and gain insight into genesis of cloud systems and their propagations over land and water. As there are strong links between the variation in monsoon rainfall and convection over the surrounding oceans, it is very important to analyze the data from ocean-based platforms such as buoys, ARGO floats, etc. and also conduct special observations over the critical regions of the oceans. Thus, a multi-pronged approach involving field experiments, analysis of existing data from conventional platforms as well as satellites, buoys, and ARGO floats, and theoretical studies with process models, complex atmospheric general circulation models, as well as coupled ocean-atmosphere models has been adopted for attaining this challenging objective.

The CTCZ programme is envisaged as is a multi-institutional programme under the leadership of the Ministry of Earth Sciences with major contributions from the different institutions under the ministry such as IMD, IITM, INCOIS, NIOT, Department of Space (and the organizations/institutes under ISRO), the Indian Air Force (IAF), the Indian Navy, Department of Science and Technology as well as scientific institutions such as the National Institution of Oceanography under CSIR, Indian Institute of Science, Indian Institutes of Technology and various universities. The science and implementation plans have been prepared by the CTCZ-SSC. A proposal for the CTCZ programme under MoES for carrying out special observational and modeling studies during 2011-2013 to achieve the scientific objectives was prepared by the scientists interested in participating in the CTCZ programme, namely, the atmospheric and oceanic sciences community. After review by the members of the CTCZ-SSC and outside experts, the proposal was revised, taking into account the comments/suggestions received. The revised proposal was discussed at the meeting of the CTCZ-SSC and approved. The proposal recommended by the CTCZ-SSC for the CTCZ programme for support from MoES is presented here.