P2C2:Collaborative Research: A Speleothem Study of the Paleoclimatology of the Yucatan Peninsula: Testing Modes and Causes of Variability in the North American Tropics

该项目的目标是重建从年际到轨道时间尺度的低纬降水变率，以更好地了解尤卡坦半岛(Yp)中尺度和大尺度大气和海洋动力学、外部强迫和反馈的水文响应。提出的驱动该区域亚轨道尺度气候机制的机制包括ENSO、热带气旋发生和与热带间辐合带(ITCZ)运动有关的降水变化，但现有的古气候记录在因果因素方面相互矛盾。该项目可能会改进降雨敏感性估计，这将代表独立于模型的经验评估。目前的国际气候模型估计，到本世纪末，该区域的降水量变化幅度很大(相对于今天的降水量变化幅度为-50%至+9%)。该项目还将支持一名代表不足的少数民族早期职业科学家，并为几名本科生提供早期研究经验。此外，研究小组将制作西班牙语和英语版本的教材和展品。研究小组将利用青藏高原洞穴中的洞穴洞穴，重建该地区全新世、最后一次冰期、海洋同位素阶段(MIS5)和MIS7至MIS9期间的水文变化特征。特别是，研究小组将根据石笋中的Delta-18Oxygen同位素定量重建降水变化。结合青藏高原现有的湖泊记录，当地的洞穴群记录可能为定量重建该地区的降水到蒸发平衡提供了独特的机会。定量的高分辨率全新世和晚更新世降水记录将：1)提供过去降雨变异性的定量估计；2)测试降雨变异性与平均ITCZ变化之间的关系；3)调查ENSO、热带海面温度和气旋在驱动青藏高原气候机制中的作用；4)提供热带水文敏感性的估计。研究人员将利用与里约秘密保护区的积极合作，该商业企业带领约50,000名游客穿过青藏高原东海岸一个部分被淹没的大型洞穴系统，用于教育和宣传目的。里约塞克莱托的洞穴系统代表了一个理想的洞穴系统，可以从该地区的石笋恢复降水变化，该地区的石笋延伸到现在大约30万年前。

This project's goal is to reconstruct low latitude precipitation variability, from interannual to orbital time scales, to better understand hydrological responses to meso and large-scale atmosphere and ocean dynamics, external forcing, and feedbacks in the Yucatan Peninsula (YP). The mechanisms proposed for driving suborbital scale climate regimes in the region include ENSO, tropical cyclogenesis and shifts in precipitation associated with movements of the Inter Tropical Convergence Zone (ITCZ), but available paleoclimate records are contradictory in terms of causal factors.The project could potentially improve rainfall sensitivity estimates that would represent an empirical assessment independent of models. Current international climate model estimates of precipitation changes in the region by the end of this century vary over a significant range (-50% to +9% relative to today). The project would also support an underrepresented minority early-career scientist and provide an early experience in research to several undergraduate students. In addition, the research team will produce educational materials and exhibits for a general audience in Spanish and English language versions.The research team will use speleothems from caves of the YP to reconstruct the character of hydrological variability in the region during the Holocene, the last glacial interval, marine isotope stage (MIS) 5, and MIS 7 to 9. In particular, the team will make quantitative reconstructions of precipitation changes based on delta-18Oxygen isotopes in stalagmites. In combination with available lacustrine records from the YP, local speleothem records may provide a unique opportunity to quantitatively reconstruct the precipitation to evaporation balance in the region. Quantitative high-resolution Holocene and Late Pleistocene precipitation records will: 1) provide quantitative estimates of past rainfall variability; 2) test the relationship between rainfall variability and shifts in mean ITCZ; 3) investigate the role of ENSO, tropical sea surface temperatures and cyclones in driving climate regimes in the YP; and 4) provide estimates of the sensitivity of tropical hydrology.The researchers will leverage an active collaboration with the Rio Secreto Reserve, a commercial enterprise that leads ~50,000 tourists through a large, partially submerged cave system on the east coast of the YP for education and outreach aims. The cave system of Rio Secreto represents an ideal cave system for reconstructing precipitation changes from stalagmites in the region extending approximately 300,000 years before the present.