Upper Ocean Characteristics in the Tropical Indian Ocean from AXBT and AXCTD Measurements

摘要

This study focuses on understanding the coupling processes that take place in air-sea interaction during the active and suppressed phases of Madden-Julian Oscillation, and specifically the initiation of MJO. Data used for this study was gathered by a NOAA WP-3D research aircraft under the framework of the Dynamics of the Madden-Julian Oscillation (DYNAMO) research project. The aircraft-based measurements extended from 01 November to 13 December 2011, when 12 research flights were flown in total. A total of 316 AXBT and 114 AXCTD ocean profilers were deployed, yielding 289 AXBT and 106 AXCTD usable profiles that were used for this thesis. For the first time, in situ measurements were made in this region of the world where MJO is initiated. This thesis documents the data quality control and quality assurance efforts for all measured profiles, especially for the AXCTD profiles. It also provides a first look into the large scale variability in the DYNAMO domain and vicinities, and the time variability of the tropical Indian Ocean during the WP-3D operation period. The measurements of the upper ocean reveal enhanced mixing in the active MJO phase and the presence of a warm, stratified, and variable upper ocean in the suppressed phase of MJO. The AXBT/AXCTD measurements also suggest increased mesoscale variability under active convection. Its feedback with the evolution of tropical convection should be investigated in future research.