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低纬度降水变率，从年际到轨道时间尺度，以更好地了解水文响应中，大尺度大气和海洋动力学，外部强迫，并在尤卡坦半岛（YP）的反馈。驱动亚轨道尺度的气候制度在该地区的机制包括厄尔尼诺/南方涛动，热带气旋和与热带辐合带（ITCZ）的运动相关的降水变化，但现有的古气候记录是矛盾的因果factors.The项目可能会提高降雨敏感性估计，将代表一个独立的模型的经验评估。目前国际气候模式对本世纪末该地区降水变化的估计有很大的差异（相对于今天的-50%到+9%）。 该项目还将支持一个代表性不足的少数民族早期职业科学家，并提供研究的早期经验，以几个本科生。 此外，该研究小组还将为普通观众制作西班牙语和英语版本的教育材料和展览。研究小组将利用YP洞穴的洞穴沉积物重建该地区全新世、末次冰期、海洋同位素阶段（MIS）5和MIS 7至9期间水文变化的特征。特别是，该团队将根据石笋中的δ-18氧同位素对降水变化进行定量重建。 结合可用的湖泊记录从YP，当地的洞穴记录可以提供一个独特的机会，定量重建该地区的降水蒸发平衡。 定量的高分辨率全新世和晚更新世降水记录将：1）提供过去降雨变率的定量估计; 2）测试降雨变率与平均ITCZ变化之间的关系; 3）调查ENSO、热带海面温度和气旋在驱动YP气候状况中的作用;和4）提供热带水文敏感性的估计。研究人员将利用与Rio Secreto Reserve的积极合作，Rio Secreto Reserve是一家商业企业，在YP东海岸的部分淹没洞穴系统，用于教育和外展目的。Rio Secreto的洞穴系统代表了一个理想的洞穴系统，可以重建该地区约30万年前石笋的降水变化。

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.