Search

In the present paper, we made an investigation of extreme rainfall events for 1860―1909 in the Korean Peninsula, and the possible atmospheric circulation state by comparing recent rainfall variability with atmospheric circulation indices. In the present study, very significant historical rainfall records and flood damage records since the mid-19th century, modern rainfall records and global climate reanalysis data were applied. Results show: (1) Pentad extreme rainfall events had undergone a clear decrease, with an abrupt falling after shifting point of 1879―1880. (2) The monthly frequencies of extreme rainfall events revealed remarkable descent trends for June–October, which changed from 29 time/pentad to 7.3 time/pentad on average, especially for July–September. (3) Almost all climate zones except for northern land displayed significant decreasing trends, nevertheless no clear incidence of extreme rainfall event was found over the typical pluvial regions. (4) Through an analogue method by comparing the extreme precipitation weather and the atmospheric mechanism for recent decades (1961―2016), we suggested that West Pacific Subtropical High had experienced a strengthen change for the past period and the typhoon-related torrential rain processes had been suppressed for the study area, and the upper air jet stream might have been displaced poleward during 1860―1909. This study made a first investigation of the extreme rainfall events since the mid-19th century applying both instrumental and documental records in the study area, and some significant findings were obtained, which will help in understanding extreme climate variability and its mechanism of late 19th century and early 20th century in the Korean Peninsula. • Several main climate variables which are related to SR-NPKP were investigated. • 13 indices having a close connection with the variability of SR-NPKP were obtained. • Neural network model was proposed for 1-yr lag prediction of SR-NPKP. [ABSTRACT FROM AUTHOR]

Amino acids in rain samples offer important information on their origin and roles in biogeochemical cycling. This paper describes the development and validation of an alternative analytical procedure for amino acids in atmospheric precipitation using gas chromatography coupled with mass spectrometry (GC–MS). The method detection limits (MDLs) of these amino acids ranged from 1.46 ng L−1 (Proline) to 135 ng L−1 (Arginine), which were much lower than previous methods like high-performance liquid chromatography (HPLC) and comparable to those with liquid chromatography-tandem mass spectrometry (LC-MS/MS). None of the target analytes were detected in blank samples, which was attributed to the optimized pretreatment protocol we adopted. We conclude that the GC–MS based technique developed in this study possesses advantage due to low detection limits. We further demonstrate the applicability of this method by analyzing rain samples from the background atmosphere of the Tibetan Plateau (TP). Similar relative abundances of amino acids were found in the TP rains, marine rains and Arctic ice. The correlations between FAAs and water- soluble ions in the Tibetan Plateau rainwaters showed that the FAAs were most likely originated from biomass burning. Given the similarity of snow and rain samples, our method also provides potential for the future analysis of amino acids in glacier ice cores. • A GC–MS analytical method for amino acids in precipitation was performed and optimized. • The developed method was characterized with high sensitivity and selectivity, while low blank value. • This is the first time that free amino acids were determined in the Tibetan Plateau rain. [ABSTRACT FROM AUTHOR]