The Yucatán Peninsula (YP) has a complex hydroclimate with many proposed drivers of interannual and longer-term variability, ranging from coupled ocean–atmosphere processes to frequency of tropical cyclones. The mid-Holocene, a time of higher Northern Hemisphere summer insolation, provides an opportunity to test the relationship between YP precipitation and ocean temperature. Here, we present a new, ∼annually resolved speleothem record of stable isotope (δ¹⁸O and δ¹³C) and trace element (Mg/Ca and Sr/Ca) ratios for a section of the mid-Holocene (5.2–5.7 kyr BP), before extensive agriculture began in the region. A meter-long stalagmite from Río Secreto, a cave system in Playa del Carmen, Mexico, was dated using U–Th geochronology and layer counting, yielding multidecadal age uncertainty (median 2SD of ±70 years). New proxy data were compared to an existing late Holocene stalagmite record from the same cave system, allowing us to examine changes in hydrology over time and to paleoclimate records from the southern YP. The δ¹⁸O, δ¹³C, and Mg/Ca data consistently indicate higher mean precipitation and lower precipitation variability during the mid-Holocene compared to the late Holocene. Despite this reduced variability, multidecadal precipitation variations were persistent in regional hydroclimate during the mid-Holocene. We therefore conclude that higher summer insolation led to increased mean precipitation and decreased precipitation variability in the northern YP but that the region is susceptible to dry periods across climate mean states. Given projected decreases in wet season precipitation in the YP’s near future, we suggest that climate mitigation strategies emphasize drought preparation.

中文翻译：

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全新世中尤卡坦半岛降水量变异性降低的证据

尤卡坦半岛（YP）的水文气候复杂，并提出了许多年际和长期变化的驱动因素，从海洋-大气耦合过程到热带气旋的发生频率不等。全新世中期，即北半球夏季较高的日照时间，为检验YP降水与海洋温度之间的关系提供了机会。在这里，我们提出稳定同位素的一个新的，~annually解决钟乳石记录（δ ¹⁸ O和δ ¹³C）和全新世中段（5.2-5.7 yr BP）之前某个区域的一部分的痕量元素（Mg / Ca和Sr / Ca）之比。来自墨西哥卡门海滩洞穴系统RíoSecreto的一米长石笋使用U-Th年代学和层计数法定年，产生年代际不确定性（中位数2SD为±70年）。将新的代理数据与同一洞穴系统中现有的晚全新世石笋记录进行了比较，从而使我们能够检查水文随时间的变化并与南部YP的古气候记录相比较。的δ ¹⁸ O，δ ¹³C和Mg / Ca数据始终表明，与全新世晚期相比，全新世中期的平均降水量更高，降水变异性更低。尽管变率降低，但全新世中期区域水气候仍存在数十年的降水变化。因此，我们得出的结论是，较高的夏季日照导致北部YP地区平均降水增加，而降水变异性降低，但是该地区在整个气候平均状态下都处于干旱期。鉴于预计在YP的近期湿季降水将减少，我们建议气候减缓策略强调干旱准备。