scholarly journals Anthropogenic agent implicated as a prime driver of shift in precipitation in eastern China in the late 1970s

2013 ◽  
Vol 13 (24) ◽  
pp. 12433-12450 ◽  
Author(s):  
T. Wang ◽  
H. J. Wang ◽  
O. H. Otterå ◽  
Y. Q. Gao ◽  
L. L. Suo ◽  
...  
Keyword(s):  
Indian Ocean ◽  
20Th Century ◽  
Yangtze River ◽  
East Asian ◽  
Eastern China ◽  
Summer Precipitation ◽  
Northern China ◽  
Yangtze River Valley ◽  
Interdecadal Shift ◽  
Asian Summer

Abstract. Observation shows that eastern China experienced an interdecadal shift in the summer precipitation during the second half of the 20th century. The summer precipitation increased in the middle and lower reaches of the Yangtze River valley, whereas it decreased in northern China. Here we use a coupled ocean–atmosphere general circulation model and multi-ensemble simulations to show that the interdecadal shift is mainly caused by the anthropogenic forcing. The rapidly increasing greenhouse gases induce a notable Indian Ocean warming, causing a westward shift of the western Pacific subtropical high (WPSH) and a southward displacement of the East Asia westerly jet (EAJ) on an interdecadal timescale, leading to more precipitation in Yangtze River valley. At the same time the surface cooling effects from the stronger convection, higher precipitation and rapidly increasing anthropogenic aerosols contribute to a reduced summer land–sea thermal contrast. Due to the changes in the WPSH, the EAJ and the land–sea thermal contrast, the East Asian summer monsoon weakened resulting in drought in northern China. Consequently, an anomalous precipitation pattern started to emerge over eastern China in the late 1970s. According to the model, the natural forcing played an opposite role in regulating the changes in WPSH and EAJ, and postponed the anthropogenically forced climate changes in eastern China. The Indian Ocean sea surface temperature is crucial to the response, and acts as a bridge to link the external forcings and East Asian summer climate together on a decadal and longer timescales. Our results further highlight the dominant roles of anthropogenic forcing agents in shaping interdecadal changes of the East Asian climate during the second half of the 20th century.

scholarly journals Anthropogenic forcing of shift in precipitation in Eastern China in late 1970s

2013 ◽  
Vol 13 (5) ◽  
pp. 11997-12032 ◽  
Author(s):  
T. Wang ◽  
H. J. Wang ◽  
O. H. Otterå ◽  
Y. Q. Gao ◽  
L. L. Suo ◽  
...  
Keyword(s):  
East Asian Summer Monsoon ◽  
Yangtze River ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Eastern China ◽  
Summer Precipitation ◽  
Northern China ◽  
Yangtze River Valley ◽  
Interdecadal Shift ◽  
Asian Summer

Abstract. Observation shows that eastern China has experienced an interdecadal shift in the summer precipitation during the second half of the 20th century. The summer precipitation increased in the middle and lower reaches of the Yangtze River Valley, whereas it decreased in northern China. Here we use a coupled ocean–atmosphere general circulation model and multi-ensemble simulations to show that the interdecadal shift is mainly caused by the combined effect of increasing global greenhouse gases and regional aerosol emissions over China. The rapidly increasing greenhouse gases induce tropical warming and a westward shift of the western Pacific subtropical high, leading to more precipitation in Yangtze River Valley. At the same time the aerosol cooling effect over land contributes to a reduced summer land–sea thermal contrast and therefore to a weakened East Asian summer monsoon and to drought in northern China. Consequently, an anomalous precipitation pattern starts to emerge in eastern China in late 1970s. Our results highlight the important role of anthropogenic forcing agents in shaping the weakened East Asian summer monsoon and associated anomalous precipitation in eastern China.

Interdecadal Connection between Arctic Temperature and Summer Precipitation over the Yangtze River Valley in the CMIP5 Historical Simulations

2020 ◽  
Author(s):  
Yuefeng Li ◽  
L. Ruby Leung
Keyword(s):  
High Latitude ◽  
Yangtze River ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Summer Precipitation ◽  
Yangtze River Valley ◽  
The Yangtze River ◽  
Surface Warming ◽  
Asian Summer ◽  
Arctic Temperature

<p>This study assesses the ability of the Coupled Model Intercomparison Project phase 5 (CMIP5) simulations in capturing the interdecadal precipitation enhancement over the Yangtze River valley (YRV) and investigates the contributions of Arctic temperature and mid- to high-latitude warming to the interdecadal variability of the East Asian summer monsoon rainfall. Six CMIP5 historical simulations including models from the Canadian Centre for Climate Modeling and Analysis (CCCma), the Beijing Climate Center, the Max Planck Institute for Meteorology, the Meteorological Research Institute, the Met Office Hadley Centre, and NCAR are used. The NCEP–NCAR reanalysis and observed precipitation are also used for comparison.Among the sixCMIP5 simulations, only CCCma can approximately simulate the enhancement of interdecadal summer precipitation over the YRV in 1990–2005 relative to 1960–75; the various relationships between the summer precipitation and surface temperature (Ts), 850-hPa winds, and 500-hPa height field (H500); and the relationships between Ts and H500 determined using regression, correlation, and singular value decomposition (SVD) analyses. It is found that CCCma can reasonably simulate the interdecadal surface warming over the boreal mid- to high latitudes in winter, spring, and summer. The summer Baikal blocking anomaly is postulated to be the bridge that links the winter and spring surface warming over the mid- to high latitude and Arctic with the enhancement of summer precipitation over the YRV. Models that missed some or all of these relationships found in CCCma and the reanalysis failed to simulate the interdecadal enhancement of precipitation over the YRV. This points to the importance of Arctic and mid- to high-latitude processes on the interdecadal variability of the East Asian summer monsoon and the challenge for global climate models to correctly simulate the linkages.</p>

scholarly journals Interdecadal Connection between Arctic Temperature and Summer Precipitation over the Yangtze River Valley in the CMIP5 Historical Simulations

2013 ◽  
Vol 26 (19) ◽  
pp. 7464-7488 ◽  
Author(s):  
Yuefeng Li ◽  
L. Ruby Leung ◽  
Ziniu Xiao ◽  
Min Wei ◽  
Qingquan Li
Keyword(s):  
High Latitude ◽  
Yangtze River ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Summer Precipitation ◽  
Yangtze River Valley ◽  
The Yangtze River ◽  
Surface Warming ◽  
Asian Summer ◽  
Arctic Temperature

Abstract This study assesses the ability of the Coupled Model Intercomparison Project phase 5 (CMIP5) simulations in capturing the interdecadal precipitation enhancement over the Yangtze River valley (YRV) and investigates the contributions of Arctic temperature and mid- to high-latitude warming to the interdecadal variability of the East Asian summer monsoon rainfall. Six CMIP5 historical simulations including models from the Canadian Centre for Climate Modeling and Analysis (CCCma), the Beijing Climate Center, the Max Planck Institute for Meteorology, the Meteorological Research Institute, the Met Office Hadley Centre, and NCAR are used. The NCEP–NCAR reanalysis and observed precipitation are also used for comparison. Among the six CMIP5 simulations, only CCCma can approximately simulate the enhancement of interdecadal summer precipitation over the YRV in 1990–2005 relative to 1960–75; the various relationships between the summer precipitation and surface temperature (Ts), 850-hPa winds, and 500-hPa height field (H500); and the relationships between Ts and H500 determined using regression, correlation, and singular value decomposition (SVD) analyses. It is found that CCCma can reasonably simulate the interdecadal surface warming over the boreal mid- to high latitudes in winter, spring, and summer. The summer Baikal blocking anomaly is postulated to be the bridge that links the winter and spring surface warming over the mid- to high latitude and Arctic with the enhancement of summer precipitation over the YRV. Models that missed some or all of these relationships found in CCCma and the reanalysis failed to simulate the interdecadal enhancement of precipitation over the YRV. This points to the importance of Arctic and mid- to high-latitude processes on the interdecadal variability of the East Asian summer monsoon and the challenge for global climate models to correctly simulate the linkages.

scholarly journals Impacts of East Asian Summer and Winter Monsoon on Interannual Variations of Mass Concentrations and Direct Radiative Forcing of Black Carbon over Eastern China

2016 ◽  
Author(s):  
Yu Hao Mao ◽  
Hong Liao
Keyword(s):  
Black Carbon ◽  
Radiative Forcing ◽  
Southern China ◽  
East Asian ◽  
Eastern China ◽  
Northern China ◽  
Winter Monsoon ◽  
Interannual Variations ◽  
Direct Radiative Forcing ◽  
Asian Summer

Abstract. We applied a global three-dimensional chemical transport model (GEOS-Chem) to examine the impacts of the East Asian monsoon on the interannual variations of mass concentrations and direct radiative forcing (DRF) of black carbon (BC) over eastern China (110–125° E, 20–45° N). With emissions fixed at the year 2010 levels, model simulations were driven by the Goddard Earth Observing System (GEOS-4) meteorological fields for 1986–2006 and the Modern Era Retrospective-analysis for Research and Applications (MERRA) meteorological fields for 1980–2010. During the period of 1986–2006, simulated JJA and DJF surface BC concentrations were higher in MERRA than in GEOS-4 by 0.30 µg m−3 (44 %) and 0.77 µg m−3 (54 %), respectively, because of the generally weaker precipitation in MERRA. We found that the strength of the East Asian summer monsoon (EASM, (East Asian winter monsoon, EAWM)) negatively correlated with simulated JJA (DJF) surface BC concentrations (r = –0.7 (–0.7) in GEOS-4 and –0.4 (–0.7) in MERRA), mainly by the changes in atmospheric circulation. Relative to the five strongest EASM years, simulated JJA surface BC concentrations in the five weakest monsoon years were higher over northern China (110–125° E, 28–45° N) by 0.04–0.09 µg m−3 (3–11 %), but lower over southern China (110–125° E, 20–27° N) by 0.03–0.04 µg m−3 (10–11 %). Compared to the five strongest EAWM years, simulated DJF surface BC concentrations in the five weakest monsoon years were higher by 0.13–0.15 µg m−3 (5–8 %) in northern China and by 0.04–0.10 µg m−3 (3–12 %) in southern China. The resulting JJA (DJF) mean all-sky DRF of BC at the top of the atmosphere were 0.04 W m−2 (3 %, (0.03 W m−2, 2 %)) higher in northern China but 0.06 W m−2 (14 %, (0.03 W m−2, 3 %)) lower in southern China. In the weakest monsoon years, the weaker vertical convection led to the lower BC concentrations above 1–2 km in southern China, and therefore the lower BC DRF in the region. The differences in vertical profiles of BC between the weakest and strongest EASM years (1998–1997) and EAWM years (1990–1996) reached up to –0.09 µg m−3 (–46 %) and –0.08 µg m−3 (–11 %) at 1–2 km in eastern China.

scholarly journals Changes in East Asian summer monsoon precipitation during the Holocene deduced from a freshwater flux reconstruction of the Changjiang (Yangtze River) based on the oxygen isotope mass balance in the northern East China Sea

2015 ◽  
Vol 11 (2) ◽  
pp. 265-281 ◽  
Author(s):  
Y. Kubota ◽  
R. Tada ◽  
K. Kimoto
Keyword(s):  
East Asian Summer Monsoon ◽  
Yangtze River ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Summer Precipitation ◽  
Freshwater Flux ◽  
The Holocene ◽  
Middle Holocene ◽  
The Past ◽  
Asian Summer

Abstract. The δ18O of seawater (δ18Ow), an indirect indicator of sea surface salinity (SSS), in the northern East China Sea (ECS) is reconstructed for the Holocene using paired analyses of Mg / Ca ratio and δ18O of planktic foraminiferal tests. According to modern observation, interannual variations in SSS during summer in the northern ECS are mainly controlled by the Changjiang (Yangtze River) discharge, which reflects summer rainfall in its drainage basin. Thus, changes in the summer SSS in the northern ECS are interpreted as reflecting variations in the East Asian summer monsoon (EASM) precipitation in the Changjiang Basin. This interpretation is confirmed by a strong relationship between the SSS in the northern ECS and the Changjiang discharge during the wet season (May–October) based on instrumental salinity records from 1951 to 2000. However, it is difficult to estimate absolute salinity values in the past with high accuracy, because the past salinity–δ18Ow regression slope, end member salinity, and δ18Ow values are not well understood. Here, we conduct δ18Ow mass-balance calculation to estimate the freshwater contribution to the surface water of the northern ECS during the last 7 kyr by assuming a simple mixing between two end members – the seawater and the Changjiang freshwater. The result indicates that there has been no gradual decreasing secular trend in the Changjiang freshwater flux from the middle Holocene to the present day, suggesting that summer insolation in the Northern Hemisphere does not regulate the EASM precipitation in the Changjiang Basin. Instead, internal feedback appears to have been more important during the Holocene. The absence of a decreasing trend in regional summer precipitation over the Changjiang Basin since the middle Holocene is contradictory to Chinese speleothems' δ18O records, suggesting that it is not possible to explain orbital changes in Chinese speleothems' δ18O during the Holocene by changes in summer precipitation, but that such changes are related to other factors such as changes in the moisture source.

scholarly journals Impacts of East Asian summer and winter monsoons on interannual variations of mass concentrations and direct radiative forcing of black carbon over eastern China

2017 ◽  
Vol 17 (7) ◽  
pp. 4799-4816 ◽  
Author(s):  
Yu-Hao Mao ◽  
Hong Liao ◽  
Hai-Shan Chen
Keyword(s):  
Black Carbon ◽  
Radiative Forcing ◽  
Southern China ◽  
East Asian ◽  
Eastern China ◽  
Northern China ◽  
Interannual Variations ◽  
Direct Radiative Forcing ◽  
Asian Summer ◽  
Mass Concentrations

Abstract. We applied a global three-dimensional chemical transport model (GEOS-Chem) to examine the impacts of the East Asian monsoon on the interannual variations of mass concentrations and direct radiative forcing (DRF) of black carbon (BC) over eastern China (110–125° E, 20–45° N). With emissions fixed at the year 2010 levels, model simulations were driven by the Goddard Earth Observing System (GEOS-4) meteorological fields for 1986–2006 and the Modern Era Retrospective-analysis for Research and Applications (MERRA) meteorological fields for 1980–2010. During the period of 1986–2006, simulated June–July–August (JJA) and December–January–February (DJF) surface BC concentrations were higher in MERRA than in GEOS-4 by 0.30 µg m−3 (44 %) and 0.77 µg m−3 (54 %), respectively, because of the generally weaker precipitation in MERRA. We found that the strength of the East Asian summer monsoon (EASM; East Asian winter monsoon, EAWM) negatively correlated with simulated JJA (DJF) surface BC concentrations (r = −0. 7 (−0.7) in GEOS-4 and −0.4 (−0.7) in MERRA), mainly by the changes in atmospheric circulation. Relative to the 5 strongest EASM years, simulated JJA surface BC concentrations in the 5 weakest monsoon years were higher over northern China (110–125° E, 28–45° N) by 0.04–0.09 µg m−3 (3–11 %), but lower over southern China (110–125° E, 20–27° N) by 0.03–0.04 µg m−3 (10–11 %). Compared to the 5 strongest EAWM years, simulated DJF surface BC concentrations in the 5 weakest monsoon years were higher by 0.13–0.15 µg m−3 (5–8 %) in northern China and by 0.04–0.10 µg m−3 (3–12 %) in southern China. The resulting JJA (DJF) mean all-sky DRF of BC at the top of the atmosphere was 0.04 W m−2 (3 %; 0.03 W m−2, 2 %) higher in northern China but 0.06 W m−2 (14 %; 0.03 W m−2, 3 %) lower in southern China. In the weakest monsoon years, the weaker vertical convection at the elevated altitudes led to the lower BC concentrations above 1–2 km in southern China, and therefore the lower BC DRF in the region. The differences in vertical profiles of BC between the weakest and strongest EASM years (1998–1997) and EAWM years (1990–1996) reached up to −0.09 µg m−3 (−46 %) and −0.08 µg m−3 (−11 %) at 1–2 km in eastern China.

scholarly journals Decreasing Influence of Summer Snow Cover Over the Western Tibetan Plateau on East Asian Precipitation Under Global Warming

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhibiao Wang ◽  
Renguang Wu ◽  
Zhang Chen ◽  
Lihua Zhu ◽  
Kai Yang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
East Asian ◽  
Summer Precipitation ◽  
Northern China ◽  
The Tibetan Plateau ◽  
Western Tibetan Plateau ◽  
Asian Summer ◽  
Tibetan Plateau Snow Cover ◽  
East Asian Summer Precipitation

In recent years, some studies emphasized the influence of western Tibetan Plateau summer snow on the East Asian summer precipitation. With the temperature rise in the past decades, the snow cover over the western Tibetan Plateau in summer has significantly decreased. This raises the question whether the impact of the Tibetan Plateau snow has changed. The present study identifies a prominent change in the influence of the western Tibetan Plateau snow cover on the East Asian summer precipitation. Before the early 2000’s, positive precipitation anomalies extend from the southeastern Tibetan Plateau through the Yangtze River to Japan and Korea and negative anomalies cover southeast China corresponding to more Tibetan Plateau snow cover. After the early 2000’s, with the reduction of snow cover variability, below-normal and above-normal summer precipitation occurs over northern China-Mongolia and northeast Asia, respectively, corresponding to more Tibetan Plateau snow cover. The change in the influence of the Tibetan Plateau snow on the East Asian summer precipitation is associated with an obvious change in the atmospheric circulation anomaly pattern. Before the early 2000’s, the wind anomalies display a south-north contrast pattern with anomalous convergence along the Yangtze River. After the early 2000’s, an anomalous cyclone occupies Northeast China with anomalous southerlies and northerlies over northeast Asia and northern China, respectively. The Tibetan Plateau snow cover variation after the early 2000’s is associated with the northeast Indian summer precipitation. The model experiments confirm that the weakened influence of summer western Tibetan Plateau snow cover on the East Asian atmospheric circulation and precipitation with the reduced snow cover anomalies.

scholarly journals Timescale-dependence of the relationship between the East Asian summer monsoon strength and precipitation over eastern China in the last millennium

2017 ◽  
Author(s):  
Jian Shi ◽  
Qing Yan ◽  
Huijun Wang
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Eastern China ◽  
Summer Precipitation ◽  
Ice Age ◽  
Last Millennium ◽  
Decadal Timescale ◽  
Asian Summer

Abstract. Precipitation/humidity proxies are widely used to reconstruct the historical East Asian summer monsoon (EASM) variation based on the assumption that summer precipitation over eastern China is closely and stably linked to the strength of EASM. However, whether the observed EASM-precipitation relationship (e.g., increased precipitation with a stronger EASM) was stable throughout the past time remains unclear. In this study, we used model outputs from the Paleoclimate Modelling Intercomparison Project Phase Ⅲ and Community Earth System Model to investigate the stability of the EASM-precipitation relationship over the last millennium on different timescales. The model results indicate that the EASM strength (defined as the regionally averaged meridional wind) enhanced in the Medieval Climate Anomaly (MCA; ~ 950–1250 A.D.), during which there was increased precipitation over eastern China, and weakened during the Little Ice Age (LIA; ~ 1500‒1800 A.D.), during which there was decreased precipitation, consistent with precipitation/humidity proxies. However, the simulated EASM-precipitation relationship is only stable on a centennial and longer timescale and is unstable on a multi-decadal timescale. The nonstationary multi-decadal EASM-precipitation relationship broadly exhibits a quasi-60-year period, which may be attributed to the internal variability of the climate system and have no significant correlation to external forcings. Our results have implications for understanding the discrepancy among various EASM proxies on a multi-decadal timescale and highlight the need to rethink reconstructed decadal EASM variations based on precipitation/humidity proxies.

Changing impact of ENSO events on the following summer rainfall in eastern China since the 1950s

2021 ◽  
pp. 1-55
Author(s):  
Linyuan Sun ◽  
Xiu-Qun Yang ◽  
Lingfeng Tao ◽  
Jiabei Fang ◽  
Xuguang Sun
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
North Pacific ◽  
Yangtze River ◽  
El Nino ◽  
East Asian ◽  
Eastern China ◽  
Summer Rainfall ◽  
The Yangtze River ◽  
Enso Events

AbstractThe El Niño-Southern Oscillation (ENSO) events which generally mature in winter profoundly affect the following summer rainfall in eastern China (ECSR), but such an impact can change significantly with decadal background. This study examines how the impact changes since the 1950s by running correlation and regression analyses. It is found that the ENSO’s impact on ECSR has undergone two decadal shifts in the late 1970s and 1990s, respectively. Sequentially, three distinct ENSO-induced ECSR anomaly patterns are categorized, which exhibit both robust and changeable sides. The robust side manifests generally more precipitation in the Yangtze River basin affected by the anomalous tropical western North Pacific anticyclone (WNPAC) in the post-El Niño summer. The changeable side is reflected in the more variable ENSO-induced rainfall anomalies north of the Yangtze River, due to the ENSO-induced different East Asian midlatitude circulation anomalies. Meanwhile, the El Niño-induced drought in South China is enhanced since the late 1970s with the intensification of the anomalous WNPAC. The ENSO’s changing impact on the ECSR stems from the changes of ENSO-induced tropical and midlatitude circulation anomalies over East Asia, which are associated with different zonal (from tropical Pacific to Indian Ocean) and meridional (from tropical Pacific to Midlatitude North Pacific) teleconnections of ENSO-induced SST anomalies. The former affects the intensity and location of the anomalous WNPAC by affecting Indian Ocean capacitor effect and convection anomalies over the tropical Indo-western Pacific. The latter modulates the ocean-to-atmosphere feedback in the midlatitude North Pacific, contributes to different local geopotential anomaly sources, and then directly or indirectly through Rossby wavetrain affects the East Asian midlatitude circulation.

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