Thesis (M.S. in Meteorology and Oceanography)--Naval Postgraduate School, June 1990. / Thesis Advisor(s): Peng, M.S. ; Chang, C.-P. "June 1990." Description based on signature page as viewed on October 19, 2009. DTIC Identifier(s): Monsoons, Arafura Sea. Author(s) subject terms: Winter monsoon surge, ITCZ, cross equatorial flow, XEF, WAT. Includes bibliographical references (p. 53-54). Also available online.

Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 63-65).

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 75-77).

Thesis (Ph. D.)--University of Hawaii at Manoa, 2002. / Includes bibliographical references (leaves 117-122).

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 80-82).

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 100-104).

Thesis (Ph. D.)--University of Adelaide, 1983. / Includes bibliographical references (leaves 320-343).

Thesis advisor: Corinne I. Wong / The South American Monsoon System is the dominant convective system over tropical South America during austral summer that is critical to a region heavily dependent on agricultural and hydroelectric production. An understanding of the controls on moisture conditions throughout Brazil is critical to assessing recurrent droughts and global climate change responses. An increasing number of monsoon reconstructions from δ¹⁸O records provide insight into last millennium variation of regional monsoon intensity. However, the relationship between past variations in monsoon intensity and local moisture conditions has yet to be investigated. In this study, we develop speleothem ⁸⁷Sr/⁸⁶Sr values as a paleo-moisture proxy from a cave site located in central Brazil. Increasing speleothem ⁸⁷Sr/⁸⁶Sr values and decreasing δ²³⁴U values over the last millennium indicate progressively wetter conditions. A similar trend in monsoon intensity is not evident in δ¹⁸O records from the region, suggesting that monsoon intensity is decoupled from the local moisture conditions through the late Holocene. The potential decoupling between the monsoon and local moisture conditions suggests that processes independent from those governing monsoon intensity may play a critical role in dictating moisture variability in the region. / Thesis (MS) — Boston College, 2016. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

The North American summer monsoon is documented, using precipitation data together with gridded data for outgoing long-wave radiation (OLR), geopotential height and wind at various levels. The upper level divergence field is diagnosed and compared with the precipitation field. A simple wet-dry precipitation index is used to date the monsoon onset at stations with daily precipitation data. The analysis shows that the monsoon rains advance northward rapidly from late June to early July. The monsoon onset is accompanied by the development of a pronounced anticyclone at the jet stream level, by sea-level pressure rises over the southwestern United States, and by decreases in climatological mean rainfall over adjacent regions of the United States, Mexico and the Caribbean. This coherent pattern of rainfall changes, that covers much of North and Central America, is shown to be dynamically consistent with the circulation changes aloft. Hence, the monsoon onset is embedded within a planetary-scale pattern of circulation changes. The demise of the monsoon and the associated upper level anticyclone, which takes place around September of the year, is more gradual than the onset, and it is accompanied by an increase in rainfall throughout much of the surrounding region. The monsoon exhibits substantial interannual variability with regard to intensity and onset date.

The mechanism of the intraseasonal oscillation in the South Asian summer monsoon region (ISO) is examined with a zonally averaged, atmospheric model (2D model), a three dimensional, atmospheric intermediate model (3D model). In both models an ocean mixed layer model is added to examine the influence of air-sea interactions on the characteristics of the ISO. Without the ocean mixed layer, an interaction between the baroclinic and barotropic modes of atmosphere can produce the ISO in both 2D and 3D models. The propagation of precipitation is caused by the phase relationship between convection and the barotropic divergence in the atmosphere. Most importantly, in the northern hemisphere, the vertical advection of July-mean easterly wind shear in regions of convection induces barotropic divergence (convergence) to the north (south) of convection. The resulting moisture convergence in the boundary layer induces the northward propagation of precipitation. The initiation of convection is also produced by the barotropic divergence in the atmosphere. Especially, the strong July-mean vertical motion at IDS causes convergence in the boundary layer between IDS and the equator. The baroclinic mode, on the other hand, acts to enhance existing convection. The differences between the ISO simulated by the 2D model and 3D models are caused by the zonal variation of winds, and atmospheric waves in the 3D model. The zonal divergence of barotropic winds enhances the westward propagation of convection along 18N, and the barotropic mode of zonal advection drives the continuous northward movement of convection across the equator. The continuous northward propagation across the equator is also enhanced by the atmospheric waves, since the Rossby wave response to the heating source in both hemispheres creates a divergence in the baroclinic mode near the equator. The inclusion of air-sea interactions in the 2D and 3D models improves the continuity in the northward propagation of convection. The meridional variation of SST enhances the boundary layer moisture convergence in front of the convection, thereby facilitating the northward propagation of convection. In addition, the SST gradient induced by the dipole type of Rossby-wave-like convection in the Indian ocean may increase the development of convection near the equator. / Thesis (Ph. D.)--University of Hawaii at Manoa, 2002. / Mode of access: World Wide Web. / Includes bibliographical references (leaves 117-122). / Electronic reproduction. / Also available by subscription via World Wide Web / xxii, 240 leaves ill. 29 cm