Influence and mechanism of solar radiation intensity on the interdecadal variability of strong Meiyu events during historical periods

Most recent studies on Meiyu over the middle and lower reaches of the Yangtze River(MLRYR)have focused on its interannual variability or the mechanism of certain abnormal events.The influence and physical mechanism of solar radiation intensity on the interdecadal frequency of strong Meiyu events over the MLRYR during historical periods were investigated using reconstructed precipitation data,reconstructed solar radiation data,and model simulation data.First,according to the solar radiation intensity,the Ming and Qing Dynasties(1470-1850)were divided into three periods of strong solar radiation and three periods of weak solar radiation.It was found that during the periods of strong solar radiation,the frequency of strong Meiyu events was significantly higher than that during the periods of weak solar radiation in the reconstructed precipitation data and model simulations.Mechanism analyses show that during the periods of strong solar radiation,the Western Pacific Subtropical High(WPSH)is stronger,and the blocking highs over the middle-high-latitudes are also stronger,which is conducive to the continuous convergence of the southward cold air and the northward warm and humid air flow at the MLRYR.Therefore,a circulation spatial pattern conducive to the occurrence of strong Meiyu events is then induced.The probability distributions of precipitation also show that,during periods of strong solar radiation,changes in circulation patterns cause the probability distribution of precipitation to shift significantly to the right,increasing the probability of strong Meiyu events occurring on the right side of the probability distribution.

One-pot calcination synthesis of Cd_(0.5)Zn_(0.5)S/g-C_(3)N_(4) photocatalyst with a step-scheme heterojunction structure

Cd_(0.5)Zn_(0.5)S/g-C_(3)N_(4)(CZS/CN)step-like heterojunction composites were facilely synthesized by annealing a sandwich of cadmium-zinc-thiourea precursors in one pot.The types of the used raw materials and the preparation procedure were simplified as much as possible in this work.The obtained hybrid exhibited enlarged specific surface area and higher separation/transfer efficiency of charge carriers compared to pure Cd_(0.5)Zn_(0.5)S and g–C_(3)N_(4),thus exhibited much enhanced photocatalytic efficiency for dye degradation under visible-light irradiation.The interfacial charge-transfer mechanism of the formed step-scheme(Sscheme)heterojunction between Cd_(0.5)Zn_(0.5)S and g–C_(3)N_(4) were carefully investigated and discussed.This work could widen the application prospect of the Cd_(x)Zn_(1-x)S/g-C_(3)N_(4) composite and provide new ideas to the design and fabrication of novel heterojunctions with robust photocatalytic performance.