scholarly journals Low-Pressure Systems and Extreme Precipitation in Southeast and East Asian Monsoon Regions

2020 ◽  
pp. 1-46
Author(s):  
Yujia You ◽  
Mingfang Ting
Keyword(s):  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
Extreme Rainfall ◽  
Low Pressure ◽  
Central China ◽  
Subtropical High ◽  
The Tibetan Plateau ◽  
Economic Implications ◽  
Low Pressure Systems

AbstractUnderstanding the physical mechanisms behind the secular trends of summer rainfall extremes over the heavily populated Southeast and East Asian monsoon regions is not only of scientific importance but also of considerable socio-economic implications. In this study, the relevance of the excessive-rain producing low-pressure systems (LPSs) to extreme rainfall is quantified. Using an objective feature-tracking algorithm, the synoptic-scale LPSs are identified and tracked in the 40-year ECMWF Interim reanalysis. The region experiences approximately 16 terrestrial and 18 marine LPSs each summer. The terrestrial LPSs form near the downwind side of the Tibetan Plateau and travel northeastward toward jet latitudes. The marine LPSs form over the western North Pacific Ocean and migrate along the western periphery of the subtropical high. While both types of LPSs account for a large portion of upper-tail rainfall, the terrestrial LPSs predominantly impact the extreme rainfall over inland areas, and the marine LPSs primarilyaffect the coastal regions where they frequently make landfall. The historical extreme rainfall trend during 1979-2018 is aligned with the changes in LPS tracks. The decreasing number of northeastward-moving terrestrial LPSs leads to an extreme rainfall dipole with negative trends in north-central China and positive trends in southern China, while the increasing number of northward-recurving marine LPSs enhances the extreme rainfall in the eastern China coast but suppresses it over the South China Sea. These trends are driven dynamically by the weakening of the monsoonal southwesterlies and the eastward retreat of the subtropical high, which are likely attributable to anthropogenic forcings.

scholarly journals Changes in Paleovegetation and Paleoclimate in China Since the Late Middle Pleistocene: A Case Study of the Dajiuhu Basin

2021 ◽  
Vol 13 (9) ◽  
pp. 4848
Author(s):  
Liwei Wu ◽  
Xinling Li ◽  
Qinghai Xu ◽  
Manyue Li ◽  
Qiufeng Zheng ◽  
...  
Keyword(s):  
Grain Size ◽  
Asian Monsoon ◽  
East Asian Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Central China ◽  
Middle Pleistocene ◽  
Pollen Record ◽  
The Difference ◽  
Late Middle Pleistocene

The East Asian monsoon system is an important part of global atmospheric circulation; however, records of the East Asian monsoon from different regions exhibit different evolutionary rhythms. Here, we show a high-resolution record of grain size and pollen data from a lacustrine sediment core of Dajiuhu Lake in Shennongjia, Hubei Province, China, in order to reconstruct the paleovegetation and paleoeclimate evolution of the Dajiuhu Basin since the late Middle Pleistocene (~237.9 ka to the present). The results show that grain size and pollen record of the core DJH-2 are consistent with the δ18O record of stalagmites from Sanbao Cave in the same area, which is closely related to the changes of insolation at the precessional (~20-kyr) scale in the Northern Hemisphere. This is different from the records of the Asian summer monsoon recorded in the Loess Plateau of North China, which exhibited dominant 100-kyr change cyclicities. We suggest that the difference between paleoclimatic records from North and South China is closely related to the east–west-oriented mountain ranges of the Qinling Mountains in central China that blocked weakened East Asia summer monsoons across the mountains during glacial periods.

scholarly journals Combined high- and low-latitude forcing of East Asian monsoon precipitation variability in the Pliocene warm period

2020 ◽  
Vol 6 (46) ◽  
pp. eabc2414
Author(s):  
Yichao Wang ◽  
Huayu Lu ◽  
Kexin Wang ◽  
Yao Wang ◽  
Yongxiang Li ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
Central China ◽  
Critical Threshold ◽  
Monsoon Precipitation ◽  
Low Latitude ◽  
Monsoon Variability ◽  
Precipitation Record ◽  
Response To Temperature

East Asian monsoon variability in the Pliocene warm world has not been sufficiently studied because of the lack of direct records. We present a high-resolution precipitation record from Pliocene fluvial-lacustrine sequences in the Weihe Basin, Central China, a region sensitive to the East Asian monsoon. The record shows an abrupt monsoon shift at ~4.2 million years ago, interpreted as the result of high-latitude cooling, with an extratropical temperature decrease across a critical threshold. The precipitation time series exhibits a pronounced ~100–thousand year periodicity and the presence of precession and half-precession cycles, which suggest low-latitude forcing. The synchronous phase but mismatched amplitudes of the East Asian monsoon precipitation proxy and eccentricity suggest a nonlinear but sensitive precipitation response to temperature forcing in the Pliocene warm world. These observations highlight the role of high- and low-latitude forcing of East Asian monsoon variations on tectonic and orbital time scales.

Aeolian delivery to Ulleung Basin, Korea (Japan Sea), during development of the East Asian Monsoon through the last 12 Ma

2019 ◽  
Vol 157 (5) ◽  
pp. 806-817 ◽  
Author(s):  
CH Anderson ◽  
RW Murray ◽  
AG Dunlea ◽  
L Giosan ◽  
CW Kinsley ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
Japan Sea ◽  
Gobi Desert ◽  
Taklimakan Desert ◽  
The Tibetan Plateau ◽  
Chinese Loess ◽  
Source Regions ◽  
The Pacific

AbstractWe reconstruct the provenance of aluminosilicate sediment deposited in Ulleung Basin, Japan Sea, over the last 12 Ma at Site U1430 drilled during Integrated Ocean Drilling Program Expedition 346. Using multivariate partitioning techniques (Q-mode factor analysis, multiple linear regressions) applied to the major, trace and rare earth element composition of the bulk sediment, we identify and quantify four aluminosilicate components (Taklimakan, Gobi, Chinese Loess and Korean Peninsula), and model their mass accumulation rates. Each of these end-members, or materials from these regions, were present in the top-performing models in all tests. Material from the Taklimakan Desert (50–60 % of aluminosilicate contribution) is the most abundant end-member through time, while Chinese Loess and Gobi Desert components increase in contribution and flux in the Plio-Pleistocene. A Korean Peninsula component is lowest in abundance when present, and its occurrence reflects the opening of the Tsushima Strait at c. 3 Ma. Variation in dust source regions appears to track step-wise Asian aridification influenced by Cenozoic global cooling and periods of uplift of the Tibetan Plateau. During early stages of the evolution of the East Asian Monsoon, the Taklimakan Desert was the major source of dust to the Pacific. Continued uplift of the Tibetan Plateau may have influenced the increase in aeolian supply from the Gobi Desert and Chinese Loess Plateau into the Pleistocene. Consistent with existing records from the Pacific Ocean, these observations of aeolian fluxes provide more detail and specificity regarding the evolution of different Asian source regions through the latest Cenozoic.

scholarly journals Assessing the Reliability of Global Monsoon Low Pressure System Track Datasets for the East Asian Monsoon

2021 ◽  
Author(s):  
Yanhong Zhang ◽  
Xiaohui Shi ◽  
Min Wen
Keyword(s):  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
Three Dimensional ◽  
Low Pressure ◽  
Dimensional Structure ◽  
Observation Data ◽  
Pressure System ◽  
Global Monsoon ◽  
Low Pressure System

Abstract Limited by the lack of atmospheric observation data over the ocean and the absence of a comprehensive set of track data for monsoon low pressure systems (MLPSs), an in-depth understanding of the activity of East Asian MLPSs has not been acquired. In recent years, advancements in satellite remote sensing and data assimilation techniques have enabled the creation of numerous high-resolution global reanalysis datasets. Additionally, with the improvement of tracking algorithms, two sets of global MLPS track data (HB2015 and VB2020) have been published. This study seeks to understand the fidelity of the two datasets with respect to the East Asian monsoon. The genesis location, movement path, and three-dimensional structure of the East Asian MLPSs obtained using HB2015 and VB2020 are compared, and the atmospheric circulation conditions of typical MLPSs are analyzed. The results show that both datasets are able to generate MLPSs with identical structure for the East Asian Monsoon, and they provide similar results in terms of the location and monthly frequency. Compared to the HB2015, the VB2020 adopts a more stringent set of thresholds for the determination of the MLPS genesis and extinction and a more rigorous tracking algorithm. Therefore, it yields a lower count of MLPSs with significantly shorter lifetimes. However, the MLPSs identified by the VB2020 all have cyclonic circulations in the proximity of their central areas as they continue their movement. In this sense, the results generated by the VB2020 are more consistent with the observed MLPSs and hence are more reliable. However, the tracking can end prematurely with this dataset.

Chinese loess and the evolution of the east Asian monsoon

2000 ◽  
Vol 24 (1) ◽  
pp. 75-96 ◽  
Author(s):  
Chun Chang Huang ◽  
Jiangli Pang ◽  
Jingpo Zhao
Keyword(s):  
Climatic Change ◽  
Atmospheric Circulation ◽  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
The Tibetan Plateau ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Chinese Loess ◽  
Climatic Variations

The history of the east Asian monsoon has been reconstructed from proxy records from the aeolian loess-palaeosol sequence in the Loess Plateau. It has been suggested that the monsoonal atmospheric circulation was initiated abruptly at 2.6 M yr BP. From about 1.2 M yrBP, the climate was characterized by contrasts between dry-cold periods brought on by the northwesterly monsoon and humid-warm periods brought about by the southeasterly monsoon. The periodic changes related to the earth’s orbital cycles have been clearly identified. Since about 0.6 M yr BP, the monsoonal climatic variations have become extremely pronounced and these correlate well with the marine isotope stages. The three-step shift in the east Asian monsoon towards greater variation seems to have been caused by the accelerated uplifting of the Tibetan Plateau. Climatic change during the last interglacial-glacial cycle recorded in the loess seems to match the SPECMAP δ18O record exactly. Six episodes of extremely strong dustfall events (brought on by the strengthened northwesterly monsoon winds) have been identified during the last glaciation. The ages of these episodes seem to match the Heinrich events in the North Atlantic and the Dansgaard-Oeschger events in Greenland. It is therefore suggested that the atmospheric circulation in east Asia is very sensitive to climatic change in high latitudes and has been responsive to global climatic change over the last 2.6 M yr. Millennial-scale climatic variations have also been identified in the Holocene loess. The article concludes by suggesting areas of research that might be undertaken in order to improve our understanding of the Chinese loess and of the evolution of the east Asian monsoon.

scholarly journals Heavy Rain-producing Terrestrial Low-Pressure Systems Over East Asian Summer Monsoon Region: Evolution, Energetics, and Trend

2021 ◽  
pp. 1-40
Author(s):  
Yujia You ◽  
Mingfang Ting ◽  
Suzana J. Camargo
Keyword(s):  
Asian Summer Monsoon ◽  
East Asian ◽  
Lower Troposphere ◽  
Summer Rainfall ◽  
Heavy Rain ◽  
Low Pressure ◽  
Environmental Drivers ◽  
The Tibetan Plateau ◽  
Monsoon Region ◽  
Low Pressure Systems

AbstractThe synoptic low-pressure systems (LPSs) formed over the downwind side of the Tibetan Plateau explain a substantial portion of summer rainfall extremes along their paths. Recent studies have found that the total extreme rainfall trend over the East Asian landmass, which features the “south flood-north drought” pattern, can be understood to a great extent by the changes in terrestrial LPSs. Yet, the energy sources fueling these storms and the environmental drivers of their long-term trends remain unclear. Utilizing a probabilistic clustering method, three clusters of terrestrial LPS tracks for the period 1979-2018 are identified. Besides the differences in trajectories that distinguish the clusters into northeastward-migrating and quasi-stationary types, prominent inter-cluster differences are found in the LPS evolution, energetics, and trends. The Lorenz energetics suggest that while condensational heating is indispensable for all three clusters, the migratory type, which has greater intensity and faster development, is more closely tied to baroclinicity. Nonetheless, the summer baroclinicity alone is not enough to sustain these LPSs as these storms dissipate quickly after propagating out of the humid monsoon region and into the drier extratropics. Over time, the occurrences of migratory LPSs decreases, and that of quasi-stationary LPSs increases. Using a Poisson model that links the LPS genesis to local environmental conditions, the decreasing occurrence of migratory LPSs is shown to result from the weakened baroclinicity, whereas the increasing occurrence of quasi-stationary LPSs is primarily driven by enhanced relative humidity and reduced steering flow in the mid-to-lower troposphere over East Asia.

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