The ITCZ (Intertropical Convergence Zone) is a geographic band with ascendant air circulation and heavy rain, sometimes referred to as the ?thermal equator?. This zone is a dominant atmospheric and oceanic feature of global climate, and its variability dominates the climate of the tropics and subtropics where most of the global population lives. Over the oceans, where it the ITCZ is narrowest and best developed, the position of the ITCZ moves seasonally between 5°S and 5°N following the maximum summer season radiation. These migrations are responsible for well-known climate phenomenon such as monsoons and seasonal droughts. Recent paleoceanographic and paleoclimate data have documented large excursions of the ITCZ in the past. Over the last 30,000 years the ITCZ has shifted rapidly (within decades to centuries) and dramatically away from its historical mean position. Past ITCZ excursions over these timescales may have been as large as ±10-15° latitude, and the climate changes in the (sub)tropics were very large indeed. The emergence of the modern day Saharan desert roughly 5,000 years age from what was previously a well-watered, lake-filled terrain is one such example. This drying of North African led to the depopulation of North Africa, and the rise of urban, stratified civilizations along the Nile Valley and the emergence of Phaeronic culture.
The objective of this work is to determine the relative sensitivity of the ITCZ position to known changes in high-latitude global ice volume and low-latitude orbital radiation forcing. Understanding sensitivity of ITCZ to known, natural climate changes is necessary to estimate possible future climate changes in a warming world. Funding of this project will support a post-doctoral researcher and undergraduate research assistants from underrepresented groups.
