Role of Pacific SSTs in improving reconstructed streamflow over the coterminous US

Abstract

Reconstructed annual streamflows using tree-ring chronologies provide useful information on moisture availability during the pre-historic period, but they have limitations in estimating high flows due to the upper bound on soil water holding capacity and trees’ metabolic growth limits. We propose a hybrid approach that uses tree-ring chronologies and climatic indices for improving high flows in 301 basins whose annual streamflows are modulated by ENSO and/or PDO. The hybrid decomposition approach relies on separating the moisture supply into the basin as outside-the-region moisture and within-the-region moisture with the former being estimated by SST indices and the latter being estimated by tree-ring chronologies. Analyses over the 301 stations from coterminous US show that the proposed approach improves the high flows and improves the overall error in the reconstructed streamflows. Potential utility of the improved reconstructed annual streamflows with improved high flows is also discussed.

Understanding the Natural Variability of Still Water Levels in the San Francisco Bay Over the Past 500 yr: Implications for Future Coastal Flood Risk

“…Extreme APC values (and the extreme SWLs they might prompt) are of particular interest for modeling coastal flood risk. So, it is critical to model and propagate the variance of regression residuals (Mukhopadhyay et al., 2018; Razavi et al., 2016). The choice of residual error model plays an important role, especially if there is low‐frequency variability in the residuals not captured in the regression.…”

“…In this study, we explore multi‐timescale natural variability in coastal flooding through innovative uses of the paleorecord to reconstruct plausible sequences of water levels and the likelihood of coastal flood events. Past studies have used a combination of tree rings and marine and nearshore paleo proxies, including geochemical proxies, to reconstruct total seasonal precipitation (Chen et al., 2015; Neukom et al., 2014; Williams et al., 2021), extreme precipitation (Borkotoky et al., 2021; Steinschneider et al., 2016, 2018), regional moisture transport (Mukhopadhyay et al., 2018; Zheng et al., 2021), drought (Baek et al., 2019; McCabe et al., 2008; Woodhouse et al., 2010), global surface temperature (Osman et al., 2021), terrestrial climate (Krapp et al., 2021), SSTs (Emile‐Geay et al., 2013, 2015; Freund et al., 2019), and sea surface salinity (Nurhati et al., 2011). These studies rely on robust relationships between environmental signals embedded within networks of paleo‐proxies and large‐scale oceanic and atmospheric conditions that determine the likelihood of those environmental responses.…”

Long‐range reservoir inflow forecasts using large‐scale climate predictors

“…The effect of climate teleconnection patterns, such as the North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and El NiÑo–Southern Oscillation (ENSO), on streamflow has been widely studied, including in the United States and Canada (Hsieh et al ., 2003; Tootle et al ., 2005; Gobena et al ., 2013; Kalra et al ., 2013; Mukhopadhyay et al ., 2018), Brazil (Calado et al ., 2019), Australia (Sen et al ., 2004), Europe (Hidalgo‐Muñoz et al ., 2015), and Iran (Saghafian et al ., 2013). Yang et al .…”