Dynamic and thermodynamic influences on precipitation in Northeast Mexico on orbital to millennial timescales

A stalagmite hydroclimate record (Tamaulipas, Mexico) from 62.5 to 5.1 ka showed (1) Atlantic and Pacific temperatures impacted precipitation changes and (2) there were dry conditions during Heinrich Stadials, possibly because moisture shifted south. The timing and mechanisms of past hydroclimate change in northeast Mexico are poorly constrained, limiting our ability to evaluate climate model performance. To address this, we present a multiproxy speleothem record of past hydroclimate variability spanning 62.5 to 5.1 ka from Tamaulipas, Mexico. Here we show a strong influence of Atlantic and Pacific sea surface temperatures on orbital and millennial scale precipitation changes in the region. Multiple proxies show no clear response to insolation forcing, but strong evidence for dry conditions during Heinrich Stadials. While these trends are consistent with other records from across Mesoamerica and the Caribbean, the relative importance of thermodynamic and dynamic controls in driving this response is debated. An isotope-enabled climate model shows that cool Atlantic SSTs and stronger easterlies drive a strong inter-basin sea surface temperature gradient and a southward shift in moisture convergence, causing drying in this region.

Automated summary

A stalagmite record from Tamaulipas, Mexico reveals that Atlantic and Pacific temperatures affect precipitation changes, and dry conditions occurred during Heinrich Stadials due to southward moisture shift. However, the timing and mechanisms of past hydroclimate change in northeast Mexico are poorly understood, which hampers the evaluation of climate model performance.