North American monsoon precipitation reconstructed from tree‐ring latewood

Abstract

The North American monsoon is a major focus of modern and paleoclimate research, but relatively little is known about interannual‐ to decadal‐scale monsoon moisture variability in the pre‐instrumental era. This study draws from a new network of subannual tree‐ring latewood width chronologies and presents a 470‐year reconstruction of monsoon (June–August) standardized precipitation for southwestern North America. Comparison with an independent reconstruction of cool‐season (October–April) standardized precipitation indicates that southwestern decadal droughts of the last five centuries were characterized not only by cool‐season precipitation deficits but also by concurrent failure of the summer monsoon. Monsoon drought events identified in the past were more severe and persistent than any of the instrumental era. The relationship between winter and summer precipitation is weak, at best, and not time stable. Years with opposing‐sign seasonal precipitation anomalies, as noted by other studies, were anomalously frequent during the mid to late 20th century.

Earlywood and Latewood Widths of Picea chihuahuana Show Contrasting Sensitivity to Seasonal Climate

“…The spatial correlations between EW-LW chronologies and SPEI ( Figure 5) agree with findings published regarding several pine species coexisting in a nearby area [32]. This confirms the existence of large spatial signals between EW and drought severity across semi-arid areas of Northern Mexico and the Southern USA confirming the value of seasonal wood production as climate proxies in this region [17,18]. Such broad-scale patterns seem to be connected to the ENSO (El Niño Southern Oscillation) variability since droughts are often connected with La Niña episodes [32,50,51].…”

The Influence of Monsoon Climate on Latewood Growth of Southwestern Ponderosa Pine

“…use of monsoon precipitation and its relationship to latewood growth. Dendrochronological [25,[36][37][38][39][40] and isotopic [24,26,27,33,41,42] analyses suggest utilization of monsoon precipitation for latewood production. Furthermore, at the ecosystem-scale, monsoon-season gross primary productivity in northern Arizona ponderosa pine forests is positively related to the amount of precipitation during this season [43].…”

Precipitation Intensity Effects on Groundwater Recharge in the Southwestern United States

“…Thus, as argued by Alley and Konikow [32], a decrease in groundwater storage can, in part, be explained by a change in the recharge behaviors in wells across the southwestern United States. It remains unknown, however, if the apparent change in the precipitation intensity is a function of climate-scale variability [79] or climate change [80].…”