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2015 Vol. 32, No. 1

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Special Section to Commemorate the 30th Anniversary of Advances in Atmospheric Sciences
LÜ Daren, ZHU Jiang, Ming XUE
2015, 32(1): 1-1. doi: 10.1007/s00376-014-0012-y
Potential Vorticity and the PV Perspective
2015, 32(1): 2-9. doi: 10.1007/s00376-014-0007-8
This paper highlights some theoretical aspects of potential vorticity (PV) and discusses some of the insights the PV perspective has given us. The topics covered include the nature of PV, its controlling role in the symmetric stability of the atmosphere, its inversion to give the flow field, Rossby waves and their coupling to give baroclinic instability, PV and midlatitude weather systems and, finally, insights into tropical motions.
From MONEX to the Global Monsoon: A Review of Monsoon System Research
DING Yihui, LIU Yanju, SONG Yafang, ZHANG Jin
2015, 32(1): 10-31. doi: 10.1007/s00376-014-0008-7
Substantial progress has been made over the past three decades since the Monsoon Experiments (MONEX) of 1978-79. Here, we review these achievements by highlighting four breakthroughs in monsoon research: (1) The identification of the coupled ocean-land-atmosphere nature of the monsoon in the process of the annual cycle of solar heating; (2) new understanding of the changes in the driving forces of monsoon systems, with anthropogenic factors (climate effects of increased greenhouse gas and aerosol emissions) playing an important role in the regulation of monsoons; (3) detection of the interdecadal- and centennial-scale variability of monsoon systems, and its attribution to the combined impact of global warming and natural (especially oceanic) effects; and (4) the emerging concept of the global monsoon and its long-term variation under the impact of global climate change. All the observational and model-derived evidence demonstrates that the monsoon system, as an important component of the global climate system, has already changed and will continue to change in the future. This picture of an evolving monsoon system poses great challenges for near-term prediction and long-term projection.
Light-absorbing Particles in Snow and Ice: Measurement and Modeling of Climatic and Hydrological impact
Yun QIAN, Teppei J. YASUNARI, Sarah J. DOHERTY, Mark G. FLANNER, William K. M. LAU, MING Jing, Hailong WANG, Mo WANG, Stephen G. WARREN, Rudong ZHANG
2015, 32(1): 64-91. doi: 10.1007/s00376-014-0010-0
Light absorbing particles (LAP, e.g., black carbon, brown carbon, and dust) influence water and energy budgets of the atmosphere and snowpack in multiple ways. In addition to their effects associated with atmospheric heating by absorption of solar radiation and interactions with clouds, LAP in snow on land and ice can reduce the surface reflectance (a.k.a., surface darkening), which is likely to accelerate the snow aging process and further reduces snow albedo and increases the speed of snowpack melt. LAP in snow and ice (LAPSI) has been identified as one of major forcings affecting climate change, e.g. in the fourth and fifth assessment reports of IPCC. However, the uncertainty level in quantifying this effect remains very high. In this review paper, we document various technical methods of measuring LAPSI and review the progress made in measuring the LAPSI in Arctic, Tibetan Plateau and other mid-latitude regions. We also report the progress in modeling the mass concentrations, albedo reduction, radiative forcing, and climatic and hydrological impact of LAPSI at global and regional scales. Finally we identify some research needs for reducing the uncertainties in the impact of LAPSI on global and regional climate and the hydrological cycle.
Arctic Sea Ice and Eurasian Climate: A Review
GAO Yongqi, SUN Jianqi, LI Fei, HE Shengping, Stein SANDVEN, YAN Qing, ZHANG Zhongshi, Katja LOHMANN, Noel KEENLYSIDE, Tore FUREVIK, SUO Lingling
2015, 32(1): 92-114. doi: 10.1007/s00376-014-0009-6
The Arctic plays a fundamental role in the climate system and has shown significant climate change in recent decades, including the Arctic warming and decline of Arctic sea-ice extent and thickness. In contrast to the Arctic warming and reduction of Arctic sea ice, Europe, East Asia and North America have experienced anomalously cold conditions, with record snowfall during recent years. In this paper, we review current understanding of the sea-ice impacts on the Eurasian climate. Paleo, observational and modelling studies are covered to summarize several major themes, including: the variability of Arctic sea ice and its controls; the likely causes and apparent impacts of the Arctic sea-ice decline during the satellite era, as well as past and projected future impacts and trends; the links and feedback mechanisms between the Arctic sea ice and the Arctic Oscillation/North Atlantic Oscillation, the recent Eurasian cooling, winter atmospheric circulation, summer precipitation in East Asia, spring snowfall over Eurasia, East Asian winter monsoon, and midlatitude extreme weather; and the remote climate response (e.g., atmospheric circulation, air temperature) to changes in Arctic sea ice. We conclude with a brief summary and suggestions for future research.
Climatic Effects of Air Pollutants over China: A Review
LIAO Hong, CHANG Wenyuan, YANG Yang
2015, 32(1): 115-139. doi: 10.1007/s00376-014-0013-x
Tropospheric ozone (O3) and aerosols are major air pollutants in the atmosphere. They have also made significant contributions to radiative forcing of climate since preindustrial times. With its rapid economic development, concentrations of air pollutants are relatively high in China; hence, quantifying the role of air pollutants in China in regional climate change is especially important. This review summarizes existing knowledge with regard to impacts of air pollutants on climate change in China and defines critical gaps needed to reduce the associated uncertainties. Measured monthly, seasonal, and annual mean surface-layer concentrations of O3 and aerosols over China are compiled in this work, with the aim to show the magnitude of concentrations of O3 and aerosols over China and to provide datasets for evaluation of model results in future studies. Ground-based and satellite measurements of O3 column burden and aerosol optical properties, as well as model estimates of radiative forcing by tropospheric O3 and aerosols are summarized. We also review regional and global modeling studies that have investigated climate change driven by tropospheric O3 and/or aerosols in China; the predicted sign and magnitude of the responses in temperature and precipitation to O3/aerosol forcings are presented. Based on this review, key priorities for future research on the climatic effects of air pollutants in China are highlighted.
Climate Change in the Subtropical Jetstream during 1950-2009
2015, 32(1): 140-148. doi: 10.1007/s00376-014-4156-6
A study of six decades (1950-2009) of reanalysis data reveals that the subtropical jetstream (STJ) of the Southern (Northern) Hemisphere between longitudes 0°E and 180°E has weakened (strengthened) during both the boreal winter (January, February) and summer (July, August) seasons. The temperature of the upper troposphere of the midlatitudes has a warming trend in the Southern Hemisphere and a cooling trend in the Northern Hemisphere. Correspondingly, the north-south temperature gradient in the upper troposphere has a decreasing trend in the Southern Hemisphere and an increasing trend in the Northern Hemisphere, which affects the strength of the STJ through the thermal wind relation. We devised a method of isotach analysis in intervals of 0.1 m s-1 in vertical sections of hemispheric mean winds to study the climate change in the STJ core wind speed, and also core height and latitude. We found that the upper tropospheric cooling of the Asian mid-latitudes has a role in the strengthening of the STJ over Asia, while throughout the rest of the globe the upper troposphere has a warming trend that weakens the STJ. Available studies show that the mid-latitude cooling of the upper troposphere over Asia is caused by anthropogenic aerosols (particularly sulphate aerosols) and the warming over the rest of the global mid-latitude upper troposphere is due to increased greenhouse gases in the atmosphere.
Original Paper
On the Radiative Properties of Ice Clouds: Light Scattering, Remote Sensing, and Radiation Parameterization
Ping YANG, Kuo-Nan LIOU, Lei BI, Chao LIU, Bingqi YI, Bryan A. BAUM
2015, 32(1): 32-63. doi: 10.1007/s00376-014-0011-z
Presented is a review of the radiative properties of ice clouds from three perspectives: light scattering simulations, remote sensing applications, and broadband radiation parameterizations appropriate for numerical models. On the subject of light scattering simulations, several classical computational approaches are reviewed, including the conventional geometric-optics method and its improved forms, the finite-difference time domain technique, the pseudo-spectral time domain technique, the discrete dipole approximation method, and the T-matrix method, with specific applications to the computation of the single-scattering properties of individual ice crystals. The strengths and weaknesses associated with each approach are discussed. With reference to remote sensing, operational retrieval algorithms are reviewed for retrieving cloud optical depth and effective particle size based on solar or thermal infrared (IR) bands. To illustrate the performance of the current solar- and IR-based retrievals, two case studies are presented based on spaceborne observations. The need for a more realistic ice cloud optical model to obtain spectrally consistent retrievals is demonstrated. Furthermore, to complement ice cloud property studies based on passive radiometric measurements, the advantage of incorporating lidar and/or polarimetric measurements is discussed. The performance of ice cloud models based on the use of different ice habits to represent ice particles is illustrated by comparing model results with satellite observations. A summary is provided of a number of parameterization schemes for ice cloud radiative properties that were developed for application to broadband radiative transfer submodels within general circulation models (GCMs). The availability of the single-scattering properties of complex ice habits has led to more accurate radiation parameterizations. In conclusion, the importance of using nonspherical ice particle models in GCM simulations for climate studies is proven.