Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we prese...

Published data and analyses from temperate and tropical aquatic systems are used to summarize knowledge about the potential impact of land-use alteration on the nitrogen biogeochemistry of tropical aquatic ecosystems, identify important patterns and recommend key needs for research. The tropical N-cycle is traced from pre-disturbance conditions through the phases of disturbance, highlighting ma...

[1] The response of hurricane frequency to climate changes in an aquaplanet configuration of a 50-km resolution atmospheric general circulation model is examined. The lower boundary condition is an energetically consistent slab ocean with a prescribed cross-equatorial ocean heat flux, which breaks the hemispheric symmetry and moves the Intertropical Convergence Zone (ITCZ) off the equator. In t...

Recent studies with climate models have demonstrated the power of extratropical forcing in causing the intertropical convergence zone (ITCZ) to shift northward or southward, and paleoclimate data supports the notion that there have been large shifts in the ITCZ over time. It is shown that similar notions apply to slab ocean simulations of global warming. Nine slab ocean model simulations from d...

Abstract. The Ptolemaic era (305–30 BCE) is an important period of Ancient Egyptian history known for its material and scientific advances, but also intermittent political social unrest in the form (sometimes widespread) revolts against elites. While role environmental pressures has long been overlooked this history, ice-core-based volcanic histories have identified as experiencing multiple not...

A meso-scale model was used to understand and describe the dynamical processes driving high ozone concentrations observed during both dry and monsoon season in monthly climatologies profiles over Lagos (Nigeria, 6.6 N, 3.3 E), obtained with the MOZAIC airborne measurements (ozone and carbon monoxide). This study focuses on ozone enhancements observed in the upper-part of the lower troposphere, ...

Abstract Precipitation often happens along organized filaments or bands of moisture such as convergence zones. Recent regional studies have shown that these arise from synoptic-scale mixing features known attracting Lagrangian coherent structures (LCSs). In this study, we present a climatology and investigate its covariability with precipitation on temporal scales ranging weekly to interannual....

Title of Dissertation: THEORETICAL AND NUMERICAL STUDIES OF TROPICAL CYCLONE DEVELOPMENT Chanh Q. Kieu, Doctor of Philosophy, 2008 Dissertation directed by: Professor Da-Lin Zhang Department of Atmospheric and Oceanic Science Part I of this dissertation is devoted to a theoretical study of tropical cyclones (TCs), in which a class of exact solutions is obtained. These solutions capture well man...

In this thesis, we have developed several zonally-symmetric models with explicit hydrological cycles to investigate important physical processes involving "monsoon-like" circulations, based on the assumption that actual monsoons can be simplified as twodimensional thermally-direct circulations. First, we examine the response of moist zonally-symmetric atmospheres to specified subtropical surfac...