scholarly journals Annual Cycle of East Asian Precipitation Simulated by CMIP6 Models

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 24
Author(s):  
Yuhan Yan ◽  
Congwen Zhu ◽  
Boqi Liu ◽  
Song Jiang

Annual cycle is fundamental in the East Asian monsoon (EAM) systems, profoundly governing the spatiotemporal distribution of the East Asian rainfall. The present study identified the dominant modes of the annual cycle in the East Asian rainfall based on the Fourier harmonic analysis and the Empirical Orthogonal Function (EOF) decomposition. We evaluated the performance of the first two leading modes (i.e., EOF-1 and EOF-2) in historical experiments (1979–2014) of the 21 released climate models of phase six of the Coupled Model Intercomparison Project (CMIP6). Comparing with the observation, although the CMIP6 models yield the essential fidelity, they still show considerable systematic biases in the amplitude and phase of the annual cycle, especially in east and south China. Most models exhibit substantial phase delays in the EOF-2 mode of the annual cycle. Some specific models (BCC-ESM1, CanESM5, and GFDL-CM4) exhibiting better performance could capture the observed annual cycle and the underlying physics in climatology and interannual variability. The limited fidelity of the EOF-2 mode of the EAM annual cycle primarily hinders the monsoon variability simulation and thus the reliable future projection. Therefore, the dominant modes of the EAM annual cycle act as the evaluate benchmark in the EAM modelling framework. Their improvement could be one possible bias correction strategy for decreasing the uncertainty in the CMIP6 simulation of the EAM.

2020 ◽  
Vol 6 (46) ◽  
pp. eabc2414
Author(s):  
Yichao Wang ◽  
Huayu Lu ◽  
Kexin Wang ◽  
Yao Wang ◽  
Yongxiang Li ◽  
...  

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.


2015 ◽  
Vol 28 (15) ◽  
pp. 5908-5921 ◽  
Author(s):  
Cheng Qian ◽  
Xuebin Zhang

Abstract The annual cycle is the largest variability for many climate variables outside the tropics. Whether human activities have affected the annual cycle at the regional scale is unclear. In this study, long-term changes in the amplitude of surface air temperature annual cycle in the observations are compared with those simulated by the climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5). Different spatial domains ranging from hemispheric to subcontinental scales in mid- to high-latitude land areas for the period 1950–2005 are considered. Both the optimal fingerprinting and a nonoptimal detection and attribution technique are used. The results show that the space–time pattern of model-simulated responses to the combined effect of anthropogenic and natural forcings is consistent with the observed changes. In particular, models capture not only the decrease in the temperature seasonality in the northern high latitudes and East Asia, but also the increase in the Mediterranean region. A human influence on the weakening in the temperature seasonality in the Northern Hemisphere is detected, particularly in the high latitudes (50°–70°N) where the influence of the anthropogenic forcing can be separated from that of the natural forcing.


2019 ◽  
Vol 5 (3) ◽  
pp. 233-244 ◽  
Author(s):  
Jasti S. Chowdary ◽  
Kaiming Hu ◽  
G. Srinivas ◽  
Yu Kosaka ◽  
Lin Wang ◽  
...  

2021 ◽  
Author(s):  
Mengqian Lu ◽  
Mengxin Pan ◽  
Lun Dai ◽  
Tat Fan Cheng

<p>2020 was exceedingly difficult for humans. As the world was experienced surge waves of COVID19, East Asia was also facing a one in a century, record-breaking flood,  as the result of a super 47-day Meiyu/Baiu stage of East Asian summer monsoon. As East Asian monsoons (EAM) follow a yearly cyclical pattern, we wonder which stage(s) were collateral damages of the extended Meiyu. Was it an early termination of the anomalous dry Spring, or was it a delayed northward propagation of the rain belt, i.e. late Mid-summer? The hypothesis stems from our recent finding (Dai et al., 2020) that the duration of the Spring stage is informative for the onset of Meiyu, while the duration of Meiyu is negatively correlated with that of Mid-summer, i.e., the longer the Meiyu, the shorter the Mid-summer. To verify this, we first positioned the 2020 pre-Meiyu, Meiyu, Mid-summer stages in the 40-year climatology annual cycle (Dai et al., 2020). Although neither the onset nor the termination was beyond the 40-year variance, Meiyu indeed hastened to arrive but postponed its departure. Rain belt stalled over the Yangtze river basin and southern Japan since mid-June; until the end of July, a planetary-scale anomalous high pressure band was in place encompassing the Arabian sea and north Pacific. It hindered the South Asian monsoonal flow to the South China Sea, curbing the northward propagation of the rain belt with assistance by both southeast-ward shift of South Asian High and lower level high pressure system persistent over the northern China. With these observations, we put forward a framework of ocean-atmosphere coupled mechanisms that traces back to the summer in 2019, and reveal the climate teleconnection and circulation systems that pave the road to the 2020 super Meiyu. With this study, we address the question of whether the 2020 super Meiyu was a “black swan” or a manifestation of ongoing systematic changes of the EAM annual cycle?</p><p> </p><p> </p><p> </p><p>Reference</p><p>Dai, L., Cheng, T. F., & Lu, M. (2020). Define East Asian monsoon annual cycle via a self‐organizing map‐based approach. Geophysical Research Letters, 47. e2020GL089542. https://doi.org/10.1029/2020GL089542</p>


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.


Sign in / Sign up

Export Citation Format

Share Document