NAO implicated as a predictor of the surface air temperature multidecadal variability over East Asia

2019 ◽  
Vol 53 (1-2) ◽  
pp. 895-905 ◽  
Author(s):  
Tiejun Xie ◽  
Jianping Li ◽  
Cheng Sun ◽  
Ruiqiang Ding ◽  
Kaicun Wang ◽  
...  
Keyword(s):  
East Asia ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Multidecadal Variability

scholarly journals Influence of the NAO on Wintertime Surface Air Temperature over East Asia: Multidecadal Variability and Decadal Prediction

2021 ◽  
Author(s):  
Jianping Li ◽  
Tiejun Xie ◽  
Xinxin Tang ◽  
Hao Wang ◽  
Cheng Sun ◽  
...  
Keyword(s):  
East Asia ◽  
Air Temperature ◽  
East Asian ◽  
Surface Air Temperature ◽  
Atlantic Multidecadal Oscillation ◽  
Warming Trend ◽  
Decadal Prediction ◽  
Delayed Effect ◽  
Multidecadal Variability ◽  
Cold Events

AbstractIn this paper, we investigate the influence of the winter NAO on the multidecadal variability of winter East Asian surface air temperature (EASAT) and EASAT decadal prediction. The observational analysis shows that the winter EASAT and East Asian minimum SAT (EAmSAT) display strong in-phase fluctuations and a significant 60–80-year multidecadal variability, apart from a long-term warming trend. The winter EASAT experienced a decreasing trend in the last two decades, which is consistent with the occurrence of extremely cold events in East Asia winters in recent years. The winter NAO leads the detrended winter EASAT by 12–18 years with the greatest significant positive correlation at the lead time of 15 years. Further analysis shows that ENSO may affect winter EASAT interannual variability, but does not affect the robust lead relationship between the winter NAO and EASAT. We present the coupled oceanic-atmospheric bridge (COAB) mechanism of the NAO influences on winter EASAT multidecadal variability through its accumulated delayed effect of ∼15 years on the Atlantic Multidecadal Oscillation (AMO) and Africa-Asia multidecadal teleconnection (AAMT) pattern. An NAO-based linear model for predicting winter decadal EASAT is constructed on the principle of the COAB mechanism, with good hindcast performance. The winter EASAT for 2020–34 is predicted to keep on fluctuating downward until ∼2025, implying a high probability of occurrence of extremely cold events in coming winters in East Asia, followed by a sudden turn towards sharp warming. The predicted 2020/21 winter EASAT is almost the same as the 2019/20 winter.

scholarly journals Contribution of SST change to multidecadal global and continental surface air temperature trends between 1910 and 2013

2019 ◽  
Vol 54 (3-4) ◽  
pp. 1295-1313
Author(s):  
Yidan Xu ◽  
Jianping Li ◽  
Cheng Sun ◽  
Xiaopei Lin ◽  
Hailong Liu ◽  
...  
Keyword(s):  
Air Temperature ◽  
North Atlantic ◽  
Surface Air Temperature ◽  
Western Pacific ◽  
Multidecadal Variability ◽  
The North ◽  
Temperature Trends ◽  
Community Atmosphere Model ◽  
Community Earth System Model ◽  
Goddard Institute

AbstractThe global mean surface air temperature (GMST) shows multidecadal variability over the period of 1910–2013, with an increasing trend. This study quantifies the contribution of hemispheric surface air temperature (SAT) variations and individual ocean sea surface temperature (SST) changes to the GMST multidecadal variability for 1910–2013. At the hemispheric scale, both the Goddard Institute for Space Studies (GISS) observations and the Community Earth System Model (CESM) Community Atmosphere Model 5.3 (CAM5.3) simulation indicate that the Northern Hemisphere (NH) favors the GMST multidecadal trend during periods of accelerated warming (1910–1945, 1975–1998) and cooling (1940–1975, 2001–2013), whereas the Southern Hemisphere (SH) slows the intensity of both warming and cooling processes. The contribution of the NH SAT variation to the GMST multidecadal trend is higher than that of the SH. We conduct six experiments with different ocean SST forcing, and find that all the oceans make positive contributions to the GMST multidecadal trend during rapid warming periods. However, only the Indian, North Atlantic, and western Pacific oceans make positive contributions to the GMST multidecadal trend between 1940 and 1975, whereas only the tropical Pacific and the North Pacific SSTs contribute to the GMST multidecadal trend between 2001 and 2013. The North Atlantic and western Pacific oceans have important impacts on modulating the GMST multidecadal trend across the entire 20th century. Each ocean makes different contributions to the SAT multidecadal trend of different continents during different periods.

scholarly journals Quantifying the contribution of anthropogenic influence to the East Asian winter monsoon in 1960–2012

2019 ◽  
Author(s):  
Xin Hao ◽  
Shengping He ◽  
Huijun Wang ◽  
Tingting Han
Keyword(s):  
East Asia ◽  
Air Temperature ◽  
General Circulation ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Surface Air Temperature ◽  
Winter Monsoon ◽  
Anthropogenic Influence ◽  
Anthropogenic Forcing ◽  
Asian Winter Monsoon

Abstract. The East Asian winter monsoon (EAWM) can be greatly influenced by many factors that can be classified as anthropogenic forcing and natural forcing. Here we explore the contribution of anthropogenic influence to the change in the EAWM over the past decades. Under all forcings observed during 1960–2013 (All-Hist run), the atmospheric general circulation model is able to reproduce the climatology and variability of the EAWM-related surface air temperature and 500 hPa geopotential height, and shows a statistically significant decreasing EAWM intensity with a trend coefficient of ∼−0.04 yr−1 which is close to the observed trend. By contrast, the simulation, which is driven by the same forcing as All-Hist run but with the anthropogenic contribution to them removed, shows no decreasing trend in the EAWM intensity. By comparing the simulations under two different forcing scenarios, we further reveal that the responses of the EAWM to the anthropogenic forcing include a rise of 0.6 ° in surface air temperature over the East Asia as well as weakening of the East Asia trough, which may result from the poleward expansion and intensification of the East Asian jet forced by the change of temperature gradient in the troposphere. Additionally, compared with the simulation without anthropogenic forcing, the frequency of strong (weak) EAWM occurrence is reduced (increased) by 45 % (from 0 to 10/7). These results indicate that the weakening of the EAWM during 1960–2013 may be mainly attributed to the anthropogenic influence.

Evaluation of MM5 and HadGEM3-RA hindcast in the CORDEX East Asia Phase Ⅱ: near-surface air temperature

2020 ◽  
Author(s):  
Seok-Woo Shin ◽  
Dong-Hyun Cha ◽  
Taehyung Kim ◽  
Gayoung Kim ◽  
Changyoung Park ◽  
...  
Keyword(s):  
East Asia ◽  
Air Temperature ◽  
Climate Models ◽  
Extreme Values ◽  
Regional Climate ◽  
Surface Air Temperature ◽  
Regional Climate Models ◽  
Near Surface ◽  
The Mean ◽  
Cordex East Asia

<p>Extreme temperature can have a devastating impact on the ecological environment (i.e., human health and crops) and the socioeconomic system. To adapt to and cope with the rapidly changing climate, it is essential to understand the present climate and to estimate the future change in terms of temperature. In this study, we evaluate the characteristics of near-surface air temperature (SAT) simulated by two regional climate models (i.e., MM5 and HadGEM3-RA) over East Asia, focusing on the mean and extreme values. To analyze extreme climate, we used the indices for daily maximum (Tmax) and minimum (Tmin) temperatures among the developed Expert Team on Climate Change Detection and Indices (ETCCDI) indices. In the results of the CORDEX-East Asia phase Ⅰ, the mean and extreme values of SAT for DJF (JJA) tend to be colder (warmer) than observation data over the East Asian region. In those of CORDEX-East Asia phase Ⅱ, the mean and extreme values of SAT for DJF and JJA have warmer than those of the CORDEX-East Asia phase Ⅰ except for those of HadGEM3-RA for DJF. Furthermore, the Extreme Temperature Range (ETR, maximum value of Tmax - minimum value of Tmin) of CORDEX-East Asia phase Ⅰ data, which are significantly different from those of observation data, are reduced in that of CORDEX-East Asia phase Ⅱ. Consequently, the high-resolution regional climate models play a role in the improvement of the cold bias having the relatively low-resolution ones. To understand the reasons for the improved and weak points of regional climate models, we investigated the atmospheric field (i.e., flow, air mass, precipitation, and radiation) influencing near-surface air temperature. Model performances for SAT over East Asia were influenced by the expansion of the western North Pacific subtropical high and the location of convective precipitation in JJA and by the contraction of the Siberian high, the spatial distribution of snowfall and associated upwelling longwave radiation in DJF.</p>

The role of surface air temperature over the east Asia on the early and late Indian Summer Monsoon Onset over Kerala

2020 ◽  
Author(s):  
Devanil Choudhury ◽  
Debashis Nath ◽  
Wen Chen
Keyword(s):  
East Asia ◽  
Air Temperature ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Late Onset ◽  
Southern China ◽  
Surface Air Temperature ◽  
Monsoon Onset ◽  
Low Level ◽  
Summer Monsoon Onset

<p>We investigated the physical mechanism for late Indian Summer Monsoon onset over Kerala<br>(MOK). 14 early and 9 late onset years are selected based on the criteria when the onset is 5 days or<br>more prior and after normal onset date (i.e 1 st June according to India Meteorological Department)<br>respectively. Then, we perform composite analyses of mean May monthly and daily evolution during<br>early and late onset years to examine the differences in monsoon circulation features prior to the MOK.<br>We find that advection of Surface Air Temperature (SAT) from the northern to the southern China and<br>the eastern Tibetan Plateau (TP) plays an important role to modulate the MOK processes. In the late<br>onset years, more low-level jet (LLJ) from the Bay of Bengal (BOB) divert towards the east Asia before<br>the onset, which is due to an extension of the low sea level pressure and high SAT over the east Asia<br>(eastern TP, east-central China). This strengthens the low-level convergence and upper level divergence<br>over the eastern TP and southern China. As a result, a significant amount of moisture from the BOB<br>is transported towards the eastern TP and southern China. Thereby, a comparatively weaker LLJ and<br>deficit low-level moisture supply over the eastern BOB maintain the key roles in modulating the MOK<br>processes.</p>

scholarly journals The Internal Multidecadal Variability of SST in the Pacific and Its Impact on Air Temperature and Rainfall over Land in the Northern Hemisphere

Atmosphere ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 153
Author(s):  
Hua Chen ◽  
Donglin He ◽  
Zhiwei Zhu
Keyword(s):  
Northern Hemisphere ◽  
Air Temperature ◽  
Critical Role ◽  
Surface Air Temperature ◽  
Ensemble Empirical Mode Decomposition ◽  
Near Surface ◽  
Multidecadal Variability ◽  
The North ◽  
Mode Decomposition ◽  
The Pacific

Based on the centennial-scale observations and re-analyses, this paper employs the ensemble empirical mode decomposition to separate the internal multidecadal variability (IMV) from the externally-forced variability of sea surface temperature (SST), and then defines new indices that represent the IMV of SST in the North Pacific (NPIMV) and South Pacific (SPIMV), respectively. The spatial structure of NPIMV/SPIMV shows remarkably positive SST anomaly only in the index-defined region; meanwhile, the temporal evolutions of NPIMV and SPIMV are uncorrelated, indicating their independence of each other. Both NPIMV and SPIMV play a critical role in the near-surface air temperature and rainfall over land in the Northern hemisphere, especially in the season when their intensity is the strongest. It is through teleconnection wave trains that NPIMV and SPIMV exert influences on remote regions. Results from another two rainfall datasets are found to be consistent in the majority of the Northern hemisphere in response to NPIMV/SPIMV, yet disagreement exists in certain regions due to large uncertainties of rainfall datasets.

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