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Extreme precipitation events, which have intensified with global warming over the past several decades, will become more intense in the future according to model projections. Although many studies have been performed, the occurrence patterns for extreme precipitation events in past and future periods in China remain unresolved. Additionally, few studies have explained how extreme precipitation events developed over the past 58 years and how they will evolve in the next 90 years as global warming becomes much more serious. In this paper, we evaluated the spatiotemporal characteristics of extreme precipitation events using indices for the frequency, quantity, intensity, and proportion of extreme precipitation, which were proposed by the World Meteorological Organization. We simultaneously analyzed the spatiotemporal characteristics of extreme precipitation in China from 2011 to 2100 using data obtained from the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. Despite the fixed threshold, 95th percentile precipitation values were also used as the extreme precipitation threshold to reduce the influence of various rainfall events caused by different geographic locations; then, eight extreme precipitation indices (EPIs) were calculated to evaluate extreme precipitation in China. We found that the spatial characteristics of the eight EPIs exhibited downward trends from south to north. In the periods 1960–2017 and 2011–2100, trends in the EPIs were positive, but there were differences between different regions. In the past 58 years, the extreme precipitation increased in the northwest, southeast, and the Tibet Plateau of China, while decreased in northern China. Almost all the trends of EPIs are positive in the next two periods (2011–2055 and 2056–2100) except for some EPIs, such as intensity of extreme precipitation, which decrease in southeastern China in the second period (2056–2100). This study suggests that the frequency of extreme precipitation events in China will progressively increase, which implies that a substantial burden will be placed on social economies and terrestrial ecological processes. [ABSTRACT FROM AUTHOR]

Measurements of precipitation isotopic composition have been conducted on a daily basis for 1 yr at Bomi, in the southeast Tibetan Plateau, an area affected by the interaction of the southwest monsoon, the westerlies, and Tibetan high pressure systems, as well as at Lhasa, situated west of Bomi. The measured isotope signals are analyzed both on an event basis and on a seasonal scale using available meteorological information and airmass trajectories. The processes driving daily and seasonal isotopic variability are investigated using multidecadal climate simulations forced by twentieth-century boundary conditions and conducted with two different isotopic atmospheric general circulation models [the isotopic version of the Laboratoire de Méétééorologie Dynamique GCM (LMDZiso) and the ECHAM4iso model]. Both models use specific nudging techniques to mimic observed atmospheric circulation fields. The models simulate a wet and cold bias on the Tibetan Plateau together with a dry bias in its southern part. A zoomed LMDZ simulation conducted with ~50-km local spatial resolution dramatically improves the simulation of isotopic compositions of precipitation on the Tibetan Plateau. Simulated water isotope fields are compared with new data and with previous observations, and regional differences in moisture origins are analyzed using back-trajectories. Here, the focus is on relationships between the water isotopes and climate variables on an event and seasonal scale and in terms of spatial and altitudinal isotopic gradients. Enhancing the spatial resolution is crucial for improving the simulation of the precipitation isotopic composition. [ABSTRACT FROM AUTHOR]

Based on the snow cover fraction (SCF) data acquired from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the NASA Terra spacecraft from 2000–2006, statistical analyses are performed to explore the spatial and temporal distribution and variation of the snow cover over the Tibetan Plateau (TP). It is found that the snow persistence over the TP varies in different elevation ranges generally becomes longer with increases in the terrain elevation. In addition, the spatial distribution of the snow cover not only depends on the elevation but also varies with terrain features, such as aspect, slope, and curvature in the local areas. With 7-year observational data, seasonal and interannual variability of snow cover has been detected. There are slight decreasing trends in SFCs from 2000–2006. With MODIS satellite snow-cover fraction data and the National Centers for Environmental Predictions and U.S. Department of Energy NCEP/DOE reanalysis II dataset, the relationship between snow cover anomalies over the TP and the East Asian Summer Monsoon (EASM) is examined. Results indicate that the onset of the EASM is closely associated with snow cover anomalies in the spring. Specifically, a positive (negative) snow cover anomaly is followed by a later (earlier) onset of the EASM. [ABSTRACT FROM AUTHOR]

We illustrate the vast expanse and the connection of anticyclonic flows of the Tibetan high (at the 200 hPa level) to the pole centred hemispheric North Polar anticyclone at the 10 hPa level during 1988. This feature of clockwise flows appears in the form of a tilted cone that appears to connect the Asian summer monsoon to the 10 hPa high. The anticyclonic flow tapers down to the vortex of the cone near the 400 hPa level. The tropical easterly jet of the Asian summer season is found near 10°N, at the 200 hPa level. Summer monsoon rainfall resides on the poleward side of this jet where the circulation carries a large negative relative vorticity. Over these precipitating regions, large-scale upward motion contributes to a transport of negative vorticity into the lower stratosphere. We show that this region of the stratosphere carries the kinematics for a large conversion of anticyclonic shear vorticity into anticyclonic curvature vorticity. Four-dimensional parcel trajectories emanating and rising from this region slowly carve out the hemispheric anticyclonic gyre at the 10 hPa level (i.e.) the North Polar anticyclone. This kinematics plays an important role in establishing this tilted system and a connection with the 10 hPa circulation. [ABSTRACT FROM AUTHOR]

A 107-cm-long lake core was drilled in South Hongshan Lake (35°10′N, 80°04′E, 5060 m a.s.l.) shows 150 yr of environmental change as inferred from ostracoda assemblages. Four species of ostracoda, which belong to four genera, have been identified. The ostracoda distribution in the core can be divided into six ostracoda assemblages as follows: OA1--Ilyocypris biplicata-- Limnocythere inopinata assemblage; OA2--Limnocythere inopinata--Leucocythere mirabilis assemblage; OA3--Leucocythere mirabilis--Limnocythere inopinata assemblage, in which dominant species is Limnocythere inopinata; OA4--Nearly ostracoda free; OA5--Eucypris inflata--Limnocythere inopinata assemblage; and OA6-- Limnocythere inopinata changes from dominant to sole species. These ostracoda assemblages, together with other proxies, imply the following environmental sequence for the past 150 yr in the study area. Shallow moving water appears in A.D. 1850--1884, followed by a warm-humid climate in 1884--1922. Lake level decreased and water temperature supported maximum ostracoda growth in 1922--1946, followed by cooling conditions in 1946--1960. From 1960 to 1980, declining lake level is closely linked with local precipitation. The period since 1982 is characterized by less precipitation and continuous aridity under warming climatic conditions. [ABSTRACT FROM AUTHOR]