scholarly journals Effects of water table dynamics on regional climate: A case study over east Asian monsoon area

2008 ◽  
Vol 113 (D21) ◽  
Author(s):  
Xing Yuan ◽  
Zhenghui Xie ◽  
Jing Zheng ◽  
Xiangjun Tian ◽  
Zongliang Yang
The Holocene ◽  
2021 ◽  
pp. 095968362199466
Author(s):  
Nannan Li ◽  
Arash Sharifi ◽  
Frank M Chambers ◽  
Yong Ge ◽  
Nathalie Dubois ◽  
...  

High-resolution proxy-based paleoenvironmental records derived from peatlands provide important insights into climate changes over centennial to millennial timescales. In this study, we present a composite climatic index (CCI) for the Hani peatland from northeastern China, based on an innovative combination of pollen-spore, phytolith, and grain size data. We use the CCI to reconstruct variations of the East Asian summer monsoon (EASM) intensity during the Holocene. This is accomplished with complete ensemble empirical mode decomposition (CEEMD), REDFIT, and cross-wavelet coherency analysis to reveal the periodicities (frequencies) of the multi-proxy derived CCI sequences and to assess potential external forcing of the EASM. The results showed that periodicities of ca. 300–350, 475, 600, 1075, and 1875 years were present in the Hani CCI sequence. Those periodicities are consistent with previously published periodicities in East Asia, indicating they are a product of external climate controls over an extensive region, rather than random variations caused by peatland-specific factors. Cross-wavelet coherency analysis between the decomposed CCI components and past solar activity reconstructions suggests that variations of solar irradiation are most likely responsible for the cyclic characteristics at 500-year frequency. We propose a conceptual model to interpret how the sun regulates the monsoon climate via coupling with oceanic and atmospheric circulations. It seems that slight solar irradiation changes can be amplified by coupling with ENSO events, which result in a significant impact on the regional climate in the East Asian monsoon area.


2013 ◽  
Vol 9 (5) ◽  
pp. 2085-2099 ◽  
Author(s):  
R. Zhang ◽  
Q. Yan ◽  
Z. S. Zhang ◽  
D. Jiang ◽  
B. L. Otto-Bliesner ◽  
...  

Abstract. Based on simulations with 15 climate models in the Pliocene Model Intercomparison Project (PlioMIP), the regional climate of East Asia (focusing on China) during the mid-Pliocene is investigated in this study. Compared to the pre-industrial, the multi-model ensemble mean (MMM) of all models shows the East Asian summer winds (EASWs) largely strengthen in monsoon China, and the East Asian winter winds (EAWWs) strengthen in south monsoon China but slightly weaken in north monsoon China in the mid-Pliocene. The MMM of all models also illustrates a warmer and wetter mid-Pliocene climate in China. The simulated weakened mid-Pliocene EAWWs in north monsoon China and intensified EASWs in monsoon China agree well with geological reconstructions. However, there is a large model–model discrepancy in simulating mid-Pliocene EAWW, which should be further addressed in the future work of PlioMIP.


2013 ◽  
Vol 9 (1) ◽  
pp. 1135-1164 ◽  
Author(s):  
R. Zhang ◽  
Q. Yan ◽  
Z. S. Zhang ◽  
D. Jiang ◽  
B. L. Otto-Bliesner ◽  
...  

Abstract. Based on the simulations with fifteen climate models in the Pliocene Model Intercomparison Project (PlioMIP), the regional climate of East Asia (focusing on China) during the mid-Pliocene is investigated in this study. Compared to the pre-industrial, the multi-model ensemble mean (MMM) of all models shows the East Asian summer wind (EASW) largely strengthens in monsoon China, and the East Asian winter wind (EAWW) strengthens in south monsoon China but slightly weakens in north monsoon China in mid-Pliocene. The MMM of all models also illustrates a warmer and wetter mid-Pliocene climate in China. The simulated weakened mid-Pliocene EAWW in north monsoon China and intensified EASW in monsoon China agree well with geological reconstructions. However, the model-model discrepancy in simulating mid-Pliocene East Asian monsoon climate, in particular EAWW, should be further addressed in the future work of PlioMIP.


2020 ◽  
Author(s):  
Bingliang Zhuang ◽  
Tijian Wang ◽  
Shu Li ◽  
Min Xie ◽  
Mengmeng Li ◽  
...  

<p>Black carbon aerosol (BC) has a significant influence on regional climate changes due to its warming effect. Such changes will feedback to BC loadings. Here, the interactions between the BC warming effect and East Asian monsoon (EAM) in both winter (EAWM) and summer (EASM) are investigated using a regional climate model RegCM4, which essentially captures the EAM features and the BC variations in China. The seasonal mean BC optical depth is 0.021 over East Asia during winter, which is 10.5% higher than that during summer. Nevertheless, the BCs direct radiative forcing is 32% stronger during summer (+1.85 W/m<sup>2</sup>). The BC direct effect would induce lower air to warm by 0.11-0.12 K, which causes an meridional circulation anomaly associated with a cyclone at 20-30 <sup>o</sup>N and southerly anomalies at 850 hPa over East Asia. Consequently, the EAM circulation is weakened during winter but enhanced during summer. Precipitation is likely increased, especially in south China during summer (by 3.73%). Compared to BC changes due to EAM interannual variations, BC changes due to its warming effect are as important, but weaker. BC surface concentrations are decreased by 1~3% during both winter and summer, by 1~3%, while the columnar BC is increased in south China during winter. During the strongest monsoon years, the BC loadings are higher at lower latitudes than those during the weakest years, resulting in more southerly meridional circulation anomalies and BC feedbacks during both winter and summer. However, the interactions between the BC warming effect and EAWM/EASM are more intense during the weakest monsoon years.</p>


2018 ◽  
Vol 31 (22) ◽  
pp. 9367-9388 ◽  
Author(s):  
B. L. Zhuang ◽  
S. Li ◽  
T. J. Wang ◽  
J. Liu ◽  
H. M. Chen ◽  
...  

AbstractBlack carbon aerosol (BC) has a significant influence on regional climate changes because of its warming effect. Such changes will feed back to BC loadings. Here, the interactions between the BC warming effect and the East Asian monsoon (EAM) in both winter (EAWM) and summer (EASM) are investigated using a regional climate model, RegCM4, that essentially captures the EAM features and the BC variations in China. The seasonal mean BC optical depth is 0.021 over East Asia during winter, which is 10.5% higher than that during summer. Nevertheless, the BC direct radiative forcing is 32% stronger during summer (+1.85 W m−2). The BC direct effect would induce lower air to warm by 0.11–0.12 K, which causes a meridional circulation anomaly associated with a cyclone at 20°–30°N and southerly anomalies at 850 hPa over East Asia. Consequently, the EAM circulation is weakened during winter but enhanced during summer. Precipitation is likely increased, especially in southern China during summer (by 3.73%). Relative to BC changes that result from EAM interannual variations, BC changes from its warming effect are as important but are weaker. BC surface concentrations are decreased by 1%–3% during both winter and summer, whereas the columnar BC is increased in south China during winter. During the strongest monsoon years, the BC loadings are higher at lower latitudes than those during the weakest years, resulting in more southerly meridional circulation anomalies and BC feedbacks during both winter and summer. However, the interactions between the BC warming effect and EAWM/EASM are more intense during the weakest monsoon years.


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