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2017 Vol. 34, No. 10

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Preface to the Special Issue on Commemorating the Centenary of Duzheng YE's Birth
Jiang ZHU
2017, 34(10): 1135-1136. doi: 10.1007/s00376-017-7002-9
The Pioneering Works of Professor Duzheng YE on Atmospheric Dispersion, Tibetan Plateau Meteorology, and Air-Sea Interaction
Ngar-Cheung LAUInstitute of Environment, Energy and Sustainability, and Department of Geography and Resource Management, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
2017, 34(10): 1137-1149. doi: 10.1007/s00376-017-6256-6
This paper provides an overview of the impacts of the original works of Professor Duzheng YE on a selected set of observational and model studies with which the present author has been associated over the past several decades. The main themes of these works include atmospheric energy dispersion, air-land interactions over the Tibetan Plateau, and El Niño-related air-sea coupling over East Asia. The dispersive behavior of observed atmospheric fluctuations accompanying cold surge events in East Asia is demonstrated. Cold air outbreaks over Korea and southern China are coincident with the successive downstream development of troughs and ridges, with the group velocity of such wave packets being notably faster than the phase propagation speed of individual troughs and ridges. In a more general context, dispersive features are also discernible from lagged teleconnection charts and cross-spectra of observed and model-simulated geopotential height variations on 10-30-day time scales. Using the output from a high-resolution general circulation model, the relative contributions of condensational, sensible, and radiative heating to the atmospheric energy budget over the Tibetan Plateau are documented. The rapid changes of the upper tropospheric Tibetan anticyclone and East Asian mei-yu ("plum rain") precipitation band associated with the development of the Asian monsoon system are described. The principal anomalies in sea level pressure, surface wind, precipitation and sea surface temperature over southeastern China and the Philippine Sea region during El Niño events are presented. The contributions of remote El Niño-related forcing and local air-sea interaction to the occurrence of these anomalies are assessed.
On Multi-Level Thinking and Scientific Understanding
Michael Edgeworth McINTYRE
2017, 34(10): 1150-1158. doi: 10.1007/s00376-017-6283-3
Professor Duzheng YE's name has been familiar to me ever since my postdoctoral years at MIT with Professors Jule CHARNEY and Norman PHILLIPS, back in the late 1960s. I had the enormous pleasure of meeting Professor YE personally in 1992 in Beijing. His concern to promote the very best science and to use it well, and his thinking on multi-level orderly human activities, reminds me not only of the communication skills we need as scientists but also of the multi-level nature of science itself. Here I want to say something (a) about what science is; (b) about why multi-level thinking——and taking more than one viewpoint——is so important for scientific as well as for other forms of understanding; and (c) about what is meant, at a deep level, by "scientific understanding" and trying to communicate it, not only with lay persons but also across professional disciplines. I hope that Professor YE would approve.
From Climate to Global Change: Following the Footprint of Prof. Duzheng YE's Research
Congbin FU
2017, 34(10): 1159-1168. doi: 10.1007/s00376-017-6300-6
To commemorate 100 years since the birth of Professor Duzheng YE, this paper reviews the contribution of Ye and his research team to the development from climate to global change science in the past 30 or so years, including: (1) the role of climate change in global change; (2) the critical time scales and predictability of global change; (3) the sensitive regions of global changetransitional zones of climate and ecosystems; and (4) orderly human activities and adaptation to global change, with a focus on the development of a proactive strategy for adaptation to such change.
Formation and Variation of the Atmospheric Heat Source over the Tibetan Plateau and Its Climate Effects
Guoxiong WU, Bian HE, Anmin DUAN, Yimin LIU, Wei YU
2017, 34(10): 1169-1184. doi: 10.1007/s00376-017-7014-5
To cherish the memory of the late Professor Duzheng YE on what would have been his 100th birthday, and to celebrate his great accomplishment in opening a new era of Tibetan Plateau (TP) meteorology, this review paper provides an assessment of the atmospheric heat source (AHS) over the TP from different data resources, including observations from local meteorological stations, satellite remote sensing data, and various reanalysis datasets. The uncertainty and applicability of these heat source data are evaluated. Analysis regarding the formation of the AHS over the TP demonstrates that it is not only the cause of the atmospheric circulation, but is also a result of that circulation. Based on numerical experiments, the review further demonstrates that land-sea thermal contrast is only one part of the monsoon story. The thermal forcing of the Tibetan-Iranian Plateau plays a significant role in generating the Asian summer monsoon (ASM), i.e., in addition to pumping water vapor from sea to land and from the lower to the upper troposphere, it also generates a subtropical monsoon-type meridional circulation subject to the angular momentum conservation, providing an ascending-air large-scale background for the development of the ASM.
Evolving Perspectives on Abrupt Seasonal Changes of the General Circulation
Jianhua LU, Tapio SCHNEIDER
2017, 34(10): 1185-1194. doi: 10.1007/s00376-017-7068-4
Professor Duzheng YE (Tu-cheng YEH) was decades ahead of his time in proposing a model experiment to investigate whether abrupt seasonal changes of the general circulation can arise through circulation feedbacks alone, unrelated to underlying inhomogeneities at the lower boundary. Here, we introduce Professor YEH's ideas during the 1950s and 1960s on the general circulation and summarize the results and suggestions of Yeh1959 on abrupt seasonal changes. We then review recent advances in understanding abrupt seasonal changes arising from model experiments like those proposed by Yeh1959. The model experiments show that circulation feedbacks can indeed give rise to abrupt seasonal transitions. In these transitions, large-scale eddies that originate in midlatitudes and interact with the zonal mean flow and meridional overturning circulations in the tropics play central roles.
Modeling Aerosol Climate Effects over Monsoon Asia: A Collaborative Research Program
Wei-Chyung WANG, Guoxing CHEN, Yangyang SONG
2017, 34(10): 1195-1203. doi: 10.1007/s00376-017-6319-8
This paper describes the latest progress of a collaborative research program entitled "Modeling Aerosol Climate Effects over Monsoon Asia", under the Climate Sciences agreement between the U.S. Department of Energy and the Chinese Academy of Sciences (in the early 1980s, Professor Duzheng YE played a critical role in leading and formalizing the agreement). Here, the rationale and approach for pursuing the program, the participants, and research activities of recent years are first described, and then the highlights of the program's key findings and relevant scientific issues, as well as follow-up studies, are presented and discussed.
Differences and Links between the East Asian and South Asian Summer Monsoon Systems: Characteristics and Variability
Ronghui HUANG, Yong LIU, Zhencai DU, Jilong CHEN, Jingliang HUANGFU
2017, 34(10): 1204-1218. doi: 10.1007/ s00376-017-7008-3
This paper analyzes the differences in the characteristics and spatio-temporal variabilities of summertime rainfall and water vapor transport between the East Asian summer monsoon (EASM) and South Asian summer monsoon (SASM) systems. The results show obvious differences in summertime rainfall characteristics between these two monsoon systems. The summertime rainfall cloud systems of the EASM show a mixed stratiform and cumulus cloud system, while cumulus cloud dominates the SASM. These differences may be caused by differences in the vertical shear of zonal and meridional circulations and the convergence of water vapor transport fluxes. Moreover, the leading modes of the two systems' summertime rainfall anomalies also differ in terms of their spatiotemporal features on the interannual and interdecadal timescales. Nevertheless, several close links with respect to the spatiotemporal variabilities of summertime rainfall and water vapor transport exist between the two monsoon systems. The first modes of summertime rainfall in the SASM and EASM regions reveal a significant negative correlation on the interannual and the interdecadal timescales. This close relationship may be linked by a meridional teleconnection in the regressed summertime rainfall anomalies from India to North China through the southeastern part over the Tibetan Plateau, which we refer to as the South Asia/East Asia teleconnection pattern of Asian summer monsoon rainfall. The authors wish to dedicate this paper to Prof. Duzheng YE, and commemorate his 100 th anniversary and his great contributions to the development of atmospheric dynamics.
Equatorial Wave Expansion of Instantaneous Flows for Diagnosis of Equatorial Waves from Data: Formulation and Illustration
2017, 34(10): 1219-1234. doi: 10.1007/s00376-017-6323-z
This paper presents a method for expanding horizontal flow variables in data using the free solutions to the shallow-water system as a basis set. This method for equatorial wave expansion of instantaneous flows (EWEIF) uses dynamic constraints in conjunction with projections of data onto parabolic cylinder functions to determine the amplitude of all equatorial waves. EWEIF allows us to decompose an instantaneous wave flow into individual equatorial waves with a presumed equivalent depth without using temporal or spatial filtering a priori. Three sets of EWEIF analyses are presented. The first set is to confirm that EWEIF is capable of recovering the individual waves constructed from theoretical equatorial wave solutions under various scenarios. The other two sets demonstrate the ability of the EWEIF method to derive time series of individual equatorial waves from instantaneous wave fields without knowing a priori exactly which waves exist in the data as well as their spatial and temporal scales using outputs of an equatorial β-channel shallow-water model and ERA-Interim data. The third set of demonstrations shows, for the first time, the continuous evolutions of individual equatorial waves in the stratosphere whose amplitude is synchronized with the background zonal wind as predicted by quasi-biennial oscillation theory.
Variable and Robust East Asian Monsoon Rainfall Response to El Niño over the Past 60 Years (1957-2016)
Bin WANG, Juan LI, Qiong HE
2017, 34(10): 1235-1248. doi: 10.1007/s00376-017-7016-3
Severe flooding occurred in southern and northern China during the summer of 2016 when the 2015 super El Niño decayed to a normal condition. However, the mean precipitation during summer (June-July-August) 2016 does not show significant anomalies, suggesting that —— over East Asia (EA) —— seasonal mean anomalies have limited value in representing hydrological hazards. Scrutinizing season-evolving precipitation anomalies associated with 16 El Niño episodes during 1957-2016 reveals that, over EA, the spatiotemporal patterns among the four categories of El Niño events are quite variable, due to a large range of variability in the intensity and evolution of El Niño events and remarkable subseasonal migration of the rainfall anomalies. The only robust seasonal signal is the dry anomalies over central North China during the El Niño developing summer. Distinguishing strong and weak El Niño impacts is important. Only strong El Niño events can persistently enhance EA subtropical frontal precipitation from the peak season of El Niño to the ensuing summer, by stimulating intense interaction between the anomalous western Pacific anticyclone (WPAC) and underlying dipolar sea surface temperature anomalies in the Indo-Pacific warm pool, thereby maintaining the WPAC and leading to a prolonged El Niño impact on EA. A weak El Niño may also enhance the post-El Niño summer rainfall over EA, but through a different physical process: the WPAC re-emerges as a forced response to the rapid cooling in the eastern Pacific. The results suggest that the skillful prediction of rainfall over continental EA requires the accurate prediction of not only the strength and evolution of El Niño, but also the subseasonal migration of EA rainfall anomalies.
Evolution of Surface Sensible Heat over the Tibetan Plateau Under the Recent Global Warming Hiatus
Lihua ZHU, Gang HUANG, Guangzhou FAN, Xia QU, Guijie ZHAO, Wei HUA
2017, 34(10): 1249-1262. doi: 10.1007/s00376-017- 6298-9
Based on regular surface meteorological observations and NCEP/DOE reanalysis data, this study investigates the evolution of surface sensible heat (SH) over the central and eastern Tibetan Plateau (CE-TP) under the recent global warming hiatus. The results reveal that the SH over the CE-TP presents a recovery since the slowdown of the global warming. The restored surface wind speed together with increased difference in ground-air temperature contribute to the recovery in SH. During the global warming hiatus, the persistent weakening wind speed is alleviated due to the variation of the meridional temperature gradient. Meanwhile, the ground surface temperature and the difference in ground-air temperature show a significant increasing trend in that period caused by the increased total cloud amount, especially at night. At nighttime, the increased total cloud cover reduces the surface effective radiation via a strengthening of atmospheric counter radiation and subsequently brings about a clear upward trend in ground surface temperature and the difference in ground-air temperature. Cloud-radiation feedback plays a significant role in the evolution of the surface temperature and even SH during the global warming hiatus. Consequently, besides the surface wind speed, the difference in ground-air temperature becomes another significant factor for the variation in SH since the slowdown of global warming, particularly at night.