Holocene hydroclimate of the subtropical Mexico: A state of the art

Abstract

The semiarid and arid subtropical Mexico has heterogeneous modern climate, and its different parts receive rainfall associated with the North American Monsoon (NAM) system, tropical storms, and westerlies. Increase in the number of paleoclimate registers with multidisciplinary studies has improved our understanding of this complex desert ecosystem during the intervals of millennial-scale global climate changes that occurred over the Holocene. This chapter describes and synthesizes the information of vegetation and dynamics of precipitation-desertification reconstructed from biological, physical, and chemical proxies in geological deposits (e.g., lacustrine deposit, paleosol, pack rat midden, sand dune, and speleothem) into four different climate regions (i.e., northeastern Mexico, NAM, desert, and south Baja) of the subtropical Mexico. The proxy records are compared with different climate forcings such as insolation strength, mean position of Intertropical Convergence Zone, El Nino-Southern Oscillation (ENSO) activity, and sea surface temperatures of the Atlantic and Pacific Oceans. Heterogeneity in hydroclimates of these climate regions is evaluated with respect to previously proposed hypotheses and a new hypothesis associated with size of the Atlantic warm pool. Tropical storms and their trajectories played important roles and contributed to the variable hydroclimates. ENSO was the dominant forcing during the late Holocene, and it generally caused reduction in total annual precipitation and enhancement in the aridity. Some parts, however, received more winter precipitation.