Tropical Moisture Exports, Extreme Precipitation and Floods in Northeast US

Abstract

Abstract.A statistically and physically based framework is put forward that investigates the 10 relationship between Tropical Moisture Exports (TME), and extreme Precipitation and floods in the Northeast United States (N.E. USA). TME correspond to the meridional transport of moist air masses, primarily born in tropical oceanic areas, to higher latitudes; contribute to the global climatology precipitation and its extremes; and are closely related to flood events, especially in the mid-latitudes.The birth process and the steering of TME have seasonal and interannual variability. In this study, we 15 explore how the TME are related to extreme precipitation and floods in the N.E. USA with a focus on seasonal variability and the potential impact of the El Niño Southern Oscillation. Links of TME to large floods events in N.E. USA in different seasons are first identified. The major moisture sources of the TME that contribute to precipitation extremes and floods in N.E. USA are then identified, together with the seasonally and interannually varying characteristics in terms of both TME birth and entrance to the 20 N.E. USA, and their subsequent contribution to extreme precipitation. We show that the extreme daily precipitation events are dominated by extreme TME entering the N.E. USA events in every season.

Hydroclimate drivers and atmospheric teleconnections of long duration floods: An application to large reservoirs in the Missouri River Basin

“…7 days before the antecedent flow condition), for both Cluster1 events and Cluster2 events, in order to understand the atmospheric conditions that lead to high antecedent flow. The analysis of associated moisture release follows the method provided in Lu et al [2013] and Lu and Lall, [2016], using the Tropical Mositure Exports (TME) dataset [Knippertz and Wernli, 2010;Knippertz et al, 2013]. The TME dataset tracks moisture transports that originated in the tropics, between 0˚ and 20˚N, and propagated to higher latitudes up to 7 days, with a 6-hourly updates of a set of meteorological parameters of the moist air parcels.…”

“…Only significant moisture transports were retained in the TME dataset, the detailed selection criteria can be found in Knippertz and Wernli, 2010;Knippertz et al, 2013 andLu et al [2013]. Previous studies [Lu et al, 2013;Lu and Lall, 2016] have shown the utility of this dataset for moisture trajectory tracking and analysis of moisture release, and successfully linked the moisture release directly to extreme precipitation and associated atmospheric circulation patterns. The diagnosis of associated moisture release and moist air tracks entering this study area [115˚W -90˚W, 35˚N -55˚N] followed similar approach as Lu et al [2013] with improvement on the organization of tracks by entering dates rather than their birth dates used in Lu et al [2013].…”

Characterizing the spatial variations and correlations of large rainstorms for landslide study

“…However, the severe storms are highly uncertain and it is difficult to ascertain and predict the future precipitation and extreme rainfall. Lu et al (2013), Lu and Lall (2016), and Najibi et al (2017) suggest a potential direction to further study the associated atmospheric circulation with moisture transport that has improved the predictability of extreme rainfall and flooding in various regions, including western Europe and the Midwest and northeast of the United States. The spatial structure found in this study also indicates that there might be a link between the distribution and the convergence of the moist air into the Hong Kong region.…”

Classification of mechanisms, Climatic Context, Areal Scaling, and Synchronization of floods: the hydroclimatology of floods in the Upper Paraná River Basin, Brazil

“…We explore the Hirschboeck's hypothesis (Hirschboeck (1988)) that exceptional floods in basis of all sizes could be related to anomalies in the large scale atmospheric circulation. This flood hydroclimatology perspective has been applied to identify the moisture transport and large scale climate patterns associated with floods in the United States (Hirschboeck (1988); Budikova et al (2010); Nakamura et al (2013); Lu and Lall (2016); Mallakpour and Villarini (2016)), Europe (Prudhomme and Genevier (2010); Jacobeit et al (2003); Bárdossy and Filiz (2005); Lu et al (2013)) and other parts of the world (Kahana et al (2002)). However, such flood studies focused in South America are nonexistent to our knowledge.…”