Search

Regional patterns of the seasonal weather and atmospheric moisture origins can impact the seasonal activities of extreme precipitation in the eastern United States (eUS). At many locations, tracks of atmospheric moisture can have different influence on timing of extreme precipitation based on the moisture origin source. In this study, we evaluate the contribution of atmospheric rivers (ARs) and their moisture origin sources to the distribution and seasonal effectivity of annual maximum precipitation (AMP) across the eUS during 1950–2021. Our results suggest that AR is a dominant mechanism of AMP in the eUS as it contributes to 75% (31 438 out of 41 976) of total AMP events recorded between 1950 and 2021. The seasonal analysis based on the circular density approach shows that spring, summer, and fall seasons display strong signals of seasonality of AMP-AR events. The spatial patterns of AMP associated with the four major moisture sources (the Pacific Ocean, the Atlantic Ocean, the combined source of the Caribbean Sea and the Gulf of Mexico, and the local source of moisture) reinforce the key role ARs play in transporting water vapor to the eUS from both oceanic and inland originated moisture. The results additionally highlight the importance of moisture subsources (major source subregions) in modulating the seasonality of extreme precipitation in the eUS. [ABSTRACT FROM AUTHOR]

In the eastern United States, the empirical probability distribution of extreme daily precipitation comprises heavy rainfall events stemming from North Atlantic tropical cyclones (TCs). At many locations, these events influence estimates of extreme value statistics (e.g., 100‐year event), thus have important bearing on the sizing of flood protection infrastructure and, in general, flood risk management and preparedness. Consequently, a characterization of location specific and regional patterns in precipitation extremes and changes therein has salience for both scientific and engineering concerns. To this end, analysis of seasonal and annual maximum daily precipitation at 667 long‐term stations across the eastern United States was pursued to ascertain recent changes in the extreme events over the 1950–2011 period. Three key results from this study illuminate less understood facets of recent changes in precipitation extremes: (a) an overall increase in the fraction of seasonal and annual maximum precipitation events linked to TCs, (b) a dramatic increase in the correlation between Accumulated Cyclone Energy Index and the leading principal component of extreme precipitation, and (c) changes in the spatial patterns of regions with highest TC‐related risk for heavy precipitation. [ABSTRACT FROM AUTHOR]

Amongst the present water treatment technologies membrane separation is gaining focus nowadays. Emulsion liquid membrane is one of the advanced strategies used for pollution removal from waste water in which the use of biosurfactant makes this approach eco-friendly technique. The norfloxacin belongs to the fluoroquinolones class of antibiotic and extensively used for urinary tract infections, which is the model pollutant in this study. Saponin was solvent extracted from soapnuts and used as biosurfactant. The main and interactive effects of parameters such as saponin concentration (0.01-0.03 g/100 mL), NaOH concentration (0.25-0.75 M) and Initial Norfloxacin concentration (25-75 mg/L) were investigated using Response Surface Methodology (RSM) - Box Behnken Design (BBD) and Artificial Neural Networks (ANN) design. The results suggested that developed 3-8-1 ANN model evaluated in terms of performance measure (R2: 0.9806, Chi square: 0.02) and error functions (RMSE: 0.11, MAE: 0.09, SEP: 1.16, MPE: 1.76) demonstrated superiority more precisely than the RSM model in terms of both data fitting and prediction capability. The optimal conditions for ELM were found to be: initial norfloxacin concentration 67.65 mg/L, saponin concentration 0.021 mg/100 mL, and NaOH concentration 0.36 M and the extraction efficiency at these parameter settings would be 91.27%. [ABSTRACT FROM AUTHOR]