Hydroclimate of northeast Mexico since the Last Glacial Maximum and possible influence of the Caribbean Low-Level Jet

The rise in average temperature of Mexico has been consistent with persistent droughts over the last decades and socio-economic disruptions in key agricultural regions. This study provided new hydroclimate data up to the Last Glacial Maximum (LGM) with a paleoclimate record from the Cieneguilla Basin of northeast Mexico. A multi-proxy approach reconstructed the millennial-to-orbital scale near-surface processes, including the hydrological balance-driven watershed erosion and evaporation-induced salinity at western limit of the Sierra Madre Oriental Mountains, and revealed a distinct transition from an overall wetter deglaciation to drier Holocene. Its resemblance with reconstructed dynamics of the Great Plains low-level jet (GPLLJ) in south-central US supported possible role of the Caribbean Low-Level Jet (CLLJ) in moisture transport. Wetter conditions over the deglaciation aligned with a phase of more spring insolation, less autumn insolation, cooler SSTs in Gulf of Mexico and tropical Atlantic, and strong GPLLJ. The early-to-middle Holocene aridification, in phase with less spring insolation and weak GPLLJ, was marked by reduced erosion, enhanced carbonate deposition and higher contribution from isotopically enriched organic matter likely from the drought tolerant C 4 /CAM plants. The early Holocene aridification across northeast Mexico and contemporary warming in tropical Atlantic might be revealing the diminished influence of meridional CLLJ flow, possibly from a shifting North Atlantic Subtropical High.