Available articles

Aerosol Indirect Effects on Warm Clouds in the Grid-Point Atmospheric Model of IAP LASG (GAMIL)

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Shi Xiang-Jun; Wang Bin; Liu Xiao-Hong; et al. - Science Press, 2010

Aerosol indirect effects on warm clouds are estimated in the Grid-point Atmospheric Model of IAP LASG (GAMIL) with a new two-moment cloud microphysics scheme using two different physically-based aerosol activation parameterizations: Abdul-Razzak and Ghan, and Nenes and Seinfeld. The annual global mean changes in shortwave cloud forcing from preindustrial times to present day (a measure of the aerosol indirect effects) estimated from these two parameterizations are remarkably similar: 0.76 W m-2 with the Abdul-Razzak and Ghan parameterization, and 0.78 W m-2 with the Nenes and Seinfeld paramete ...

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Aerosol Indirect Effects on Warm Clouds in the Grid-Point Atmospheric Model of IAP LASG (GAMIL)

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10043

Xiang-Jun Shi ; Bin Wang ; Xiao-Hong Liu ; Ming-Huai Wang ; Li-Juan Li ; Li Dong

in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.237-241

Aerosol indirect effects on warm clouds are estimated in the Grid-point Atmospheric Model of IAP LASG (GAMIL) with a new two-moment cloud microphysics scheme using two different physically-based aerosol activation parameterizations: Abdul-Razzak and Ghan, and Nenes and Seinfeld. The annual global mean changes in shortwave cloud forcing from preindustrial times to present day (a measure of the aerosol indirect effects) estimated from these two parameterizations are remarkably similar: 0.76 W m-2 with the Abdul-Razzak and Ghan parameterization, and 0.78 W m-2 with the Nenes and Seinfeld parameterization. Physically-based parameterizations can provide robust representations of aerosol effects on droplet nucleation, meaning that aerosol activation is no longer the most uncertain factor in modeling aerosol indirect effects.

Language(s): English

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Tags: Aerosols ; Atmosphere ; Impact studies ; Warm cloud ; Observations ; Region II - Asia Add tag

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An Arctic Sea Ice Simulation Using an Ocean-Ice Coupled Model

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Sun Hong-Chuan; Zhou Guang-Qing - Science Press, 2010

This paper evaluates the simulation of Arctic sea ice states using an ocean-ice coupled model that employs LASG/IAP (the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics/ the Institute of Atmospheric Physics) Climate Ocean Model (LICOM) and the sea-ice model from the Bergen Climate Model (BCM). It is shown that the coupled model can reasonably reproduce the major characteristics of the mean state, annual cycle, and inter-annual variability of the Arctic sea ice concentration. The coupled model also shows biases that were generally pre-sented in ...

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An Arctic Sea Ice Simulation Using an Ocean-Ice Coupled Model

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10046

Hong-Chuan Sun ; Guang-Qing Zhou

in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.219-223

This paper evaluates the simulation of Arctic sea ice states using an ocean-ice coupled model that employs LASG/IAP (the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics/ the Institute of Atmospheric Physics) Climate Ocean Model (LICOM) and the sea-ice model from the Bergen Climate Model (BCM). It is shown that the coupled model can reasonably reproduce the major characteristics of the mean state, annual cycle, and inter-annual variability of the Arctic sea ice concentration. The coupled model also shows biases that were generally pre-sented in other models, such as the underestimation of summer sea ice concentration and thickness as well as the unsatisfactory sea ice velocity. Sensitivity experiments indicate that the insufficient performance of the ocean model at high latitudes may be the main reason for the biases in the coupled model. The smoother and the fake “island”, which had to be used due to the model’s grid in the North Pole region, likely caused the ocean model’s weak performance. Sea ice model thermodynamics are also responsible for the sea ice simulation biases. There-fore, both the thermodynamic module of the sea ice com-ponent and the model grid of the ocean component need to be further improved.

Language(s): English

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Tags: Arctic ; Sea ice ; Glaciology ; Oceans ; Climate simulation Add tag

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Possible Impact of the Boreal Spring Antarctic Oscillation on the North American Summer Monsoon

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Sun Jian-Qi - Science Press, 2010

This study examined the relationship between the boreal spring (April-May) Antarctic Oscillation (AAO) and the North American summer monsoon (NASM) (July-September) for the period of 1979-2008. The results show that these two systems are closely related. When the spring AAO was stronger than normal, the NASM tended to be weaker, and there was less rainfall over the monsoon region. The opposite NASM situation corresponded to a weaker spring AAO. Further analysis explored the possible mechanism for the delayed impact of the boreal spring AAO on the NASM. It was found that the tropical Atlantic s ...

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Possible Impact of the Boreal Spring Antarctic Oscillation on the North American Summer Monsoon

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10041

Jian-Qi Sun

in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.232-236

This study examined the relationship between the boreal spring (April-May) Antarctic Oscillation (AAO) and the North American summer monsoon (NASM) (July-September) for the period of 1979-2008. The results show that these two systems are closely related. When the spring AAO was stronger than normal, the NASM tended to be weaker, and there was less rainfall over the monsoon region. The opposite NASM situation corresponded to a weaker spring AAO. Further analysis explored the possible mechanism for the delayed impact of the boreal spring AAO on the NASM. It was found that the tropical Atlantic sea surface temperature (SST) plays an important role in the connection between the two phenomena. The variability of the boreal spring AAO can produce anomalous SSTs over the tropical Atlantic. These SST anomalies can persist from spring to summer and can influence the Bermuda High, affecting water vapor transportation to the monsoon region. Through these processes, the boreal spring AAO exerts a significantly delayed impact on the amount of NASM precipitation. Thus, information about the boreal spring AAO is valuable for the prediction of the NASM.

Language(s): English

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Tags: North America ; Region IV - North America, Central America and the Caribbean ; Aurora ; Monsoon ; Antarctic Oscillation (AAO) Add tag

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The Relationship between Total Ozone and Local Climate at Kunming Using Dobson and TOMS Data

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Wang Jun; Wang Hui-Jun - Science Press, 2010

This paper uses Dobson spectrometer total ozone data, Total Ozone Mapping Spectrometer (TOMS) data and radiosonde reports from Kunming, which is located in southwest China, from 1980 to 2008 to analyze the total ozone-climate relationship. The total ozone decadal long-term trend and abrupt change were studied using enhanced Dobson data whose missing data were amended by the TOMS data. Stepwise linear regression was used for the selection of the key factors that influence total ozone, including temperatures, geopotential heights, depressions of the dew point, wind velocities, and total solar ra ...

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The Relationship between Total Ozone and Local Climate at Kunming Using Dobson and TOMS Data

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10044

Jun Wang ; Hui-Jun Wang

in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.207-212

This paper uses Dobson spectrometer total ozone data, Total Ozone Mapping Spectrometer (TOMS) data and radiosonde reports from Kunming, which is located in southwest China, from 1980 to 2008 to analyze the total ozone-climate relationship. The total ozone decadal long-term trend and abrupt change were studied using enhanced Dobson data whose missing data were amended by the TOMS data. Stepwise linear regression was used for the selection of the key factors that influence total ozone, including temperatures, geopotential heights, depressions of the dew point, wind velocities, and total solar radiation. The relationship between the selected factors and total ozone was analyzed using the methods of stepwise regression and partial least squares regression (PLSR). Results showed that although the PLSR method was slightly better and more reasonable to study the relationship than stepwise regression, while the two regression results were only slightly different. It was also suggested that local climate, especially local circulation and temperature, were important for the variations in total ozone, and the local climate could almost linearly explain 80% of the variance of total ozone. The relationship also indicated that the abrupt change of total ozone in the year 1994 may be related to abrupt local climate change.

Language(s): English

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Tags: China ; Atmospheric circulation ; Climate ; Ozone Add tag

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Diapycnal Mixing in Transient Responses of the Atlantic Meridional Overturning Circulation in an Enhanced Freshwater Perturbation Experiment

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Yu Lei; Gao Yong-Qi; Helge Drange; et al. - Science Press, 2010

It has been reported recently that the simulated Atlantic meridional overturning circulation (AMOC) using the coupled Bergen climate model (BCM) showed initial intensity declines followed by gradual recoveries over a 150-year enhanced freshwater input experiment. Stratification-dependent oceanic diapycnal mixing has been hypothesized as a reason for the simulated recovery of the AMOC. This study investigated the role of diapycnal mixing in transient responses of simulated AMOCs. Our results showed that stratification-dependent diapycnal mixing can cause stronger upwelling of deep water in the ...

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Diapycnal Mixing in Transient Responses of the Atlantic Meridional Overturning Circulation in an Enhanced Freshwater Perturbation Experiment

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10045

Lei Yu ; Yong-Qi Gao ; Drange Helge ; Odd Helge Ottera

in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.201-206

It has been reported recently that the simulated Atlantic meridional overturning circulation (AMOC) using the coupled Bergen climate model (BCM) showed initial intensity declines followed by gradual recoveries over a 150-year enhanced freshwater input experiment. Stratification-dependent oceanic diapycnal mixing has been hypothesized as a reason for the simulated recovery of the AMOC. This study investigated the role of diapycnal mixing in transient responses of simulated AMOCs. Our results showed that stratification-dependent diapycnal mixing can cause stronger upwelling of deep water in the tropical Atlantic than that produced under conditions of fixed diapycnal mixing. Moreover, simulated AMOCs were more sensitive to active stratification-dependent diapycnal mixing than fixed mixing. However, stratification-dependent diapycnal mixing cannot be conclusively singled out as the critical cause of the recoveries of simulated AMOCs under enhanced-freshwater inputs.

Language(s): English

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Tags: Region II - Asia ; China ; Climate model ; Atmospheric circulation ; Climate ; Ocean-atmosphere interaction ; Modelling Add tag

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Comparisons of Low-Level Circulation Characteristics between ECHAM5/MPI-OM Results and NCEP/NCAR Re-Analysis Data in East Asia

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Zhao De-Ming; Fu Cong-Bin - Science Press, 2010

Regional climate models (RCMs) can provide far more precise information than general circulation models (GCMs). However, RCMs depend on GCM results for re-analysis products providing boundary conditions, especially for future climate scenarios. Meanwhile, the capacity of RCMs to reproduce precipitation is strongly connected to its performance on circulation and moisture transport simulations in the low troposphere, which is the key problem with RCMs at present. In the Regional Climate Model Inter-comparison Project for East Asia (RMIP III), the results of ECHAM5/MPI-OM (the European Centre-Ham ...

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Comparisons of Low-Level Circulation Characteristics between ECHAM5/MPI-OM Results and NCEP/NCAR Re-Analysis Data in East Asia

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10028

De-Ming Zhao ; Cong-Bin Fu

in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.189-194

Regional climate models (RCMs) can provide far more precise information than general circulation models (GCMs). However, RCMs depend on GCM results for re-analysis products providing boundary conditions, especially for future climate scenarios. Meanwhile, the capacity of RCMs to reproduce precipitation is strongly connected to its performance on circulation and moisture transport simulations in the low troposphere, which is the key problem with RCMs at present. In the Regional Climate Model Inter-comparison Project for East Asia (RMIP III), the results of ECHAM5/MPI-OM (the European Centre-Hamburg model version 5/Max Planck Institute Ocean Model, simplified as E5OM here) are used to drive RCMs for the past (1978-2000) climate simulation and future (2038-70) climate scenarios. Therefore, it is necessary to test E5OM’s ability to represent atmospheric circulation, which defines the large-scale circulation for RCMs. Here, comparisons between the E5OM results and NCEP/NCAR (simplified as NCEP) re-analysis data in the low troposphere for the years 1978 to 2000 are performed. The results show that E5OM results can generally reproduce atmospheric circulations in the low troposphere. However, differences can be detected in East Asian summer and winter monsoon simulations. For summer, there is an anti-cyclone circulation for the difference of wind vector at 850 hPa in Southeast China, the Indo-China Peninsula, the South China Sea, and the northwestern Pacific. For winter, due to the weaker northwesterly wind in Northeast Asia, the northeasterly wind from the Indo-China Peninsula to Taiwan in E5OM extends northward with greater intensity than that in NCEP. These differences will have a considerable influence on the low level atmospheric circulation and water vapor transport as well as the location and intensity of the precipitation. Therefore, when E5OM results are to be used as initial and boundary conditions to drive RCMs, the differences between NCEP and E5OM should be considered.

Language(s): English

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Tags: Region II - Asia ; China ; Climate model ; Atmospheric circulation ; Climate ; Modelling Add tag

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Thunder Events in China: 1980-2008

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Zheng Lin-Lin - Science Press, 2010

Using data collected at 517 weather stations in contiguous China over the period 1980-2008, characteristics of thunder events have been investigated. These characteristics include geographical distribution, interdecadal variation, annual variation, and seasonal variation. The areas with the highest frequencies of thunder events are located in the central Tibetan Plateau, Yunnan, Guangxi, and Guangdong. The annual number of thunder days increases from northern to southern China. But the frequency of thunder events over mountains and plateaus is much higher than the frequency of events over plai ...

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Thunder Events in China: 1980-2008

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10027

Lin-Lin Zheng

in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.181-188

Using data collected at 517 weather stations in contiguous China over the period 1980-2008, characteristics of thunder events have been investigated. These characteristics include geographical distribution, interdecadal variation, annual variation, and seasonal variation. The areas with the highest frequencies of thunder events are located in the central Tibetan Plateau, Yunnan, Guangxi, and Guangdong. The annual number of thunder days increases from northern to southern China. But the frequency of thunder events over mountains and plateaus is much higher than the frequency of events over plains in the same latitude. The interdecadal variation of events shows that the frequency of thunder occurrences was highest during the 1980s, decreased during the 1990s, and increased slightly afterwards. Thunder occurrences vary with the season, northward in May and retreating southward in September.

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Tags: China ; History ; Thunderstorm ; Weather Add tag

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Kolmogorov Constants of Atmospheric Turbulence over a Homogeneous Surface

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Cheng Xue-Ling; Wang Bing-Lan; Hu Fei; et al. - Science Press, 2010

In this paper, the authors use ultrasonic data over a homogeneous surface to calculate the Kolmogorov constants of velocity, temperature, CO2, and water vapor. The authors find that the constants are all within the range determined by former experiments and that they are universally independent of the stability.

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Kolmogorov Constants of Atmospheric Turbulence over a Homogeneous Surface

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10033

Xue-Ling Cheng ; Bing-Lan Wang ; Fei Hu ; Rong Zhu

in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.195-200

In this paper, the authors use ultrasonic data over a homogeneous surface to calculate the Kolmogorov constants of velocity, temperature, CO2, and water vapor. The authors find that the constants are all within the range determined by former experiments and that they are universally independent of the stability.

Language(s): English

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Tags: Region II - Asia ; China ; Atmosphere ; Carbon dioxide (CO2) ; Air temperature Add tag

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Analysis of South Asian Monsoons within the Context of Increasing Regional Black Carbon Aerosols

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Mahmood Rashed; Yao Jin-Feng - Science Press, 2010

South Asian monsoons were analyzed within the context of increasing emissions of black carbon (BC) aerosols using a global atmospheric general circulation model. The BC aerosols were allowed to increase only over the south Asian domain to analyze the impacts of regional black carbon over the climatological patterns of monsoons. The black carbon significantly absorbed the incoming short wave radiation in the atmosphere, a result that is consistent with previous studies. Pre-monsoon (March-April-May) rainfall showed positive anomalies, particularly for some coastal regions of India. The summer ( ...

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Analysis of South Asian Monsoons within the Context of Increasing Regional Black Carbon Aerosols

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10037

Rashed Mahmood ; Jin-Feng Yao

in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.224-231

South Asian monsoons were analyzed within the context of increasing emissions of black carbon (BC) aerosols using a global atmospheric general circulation model. The BC aerosols were allowed to increase only over the south Asian domain to analyze the impacts of regional black carbon over the climatological patterns of monsoons. The black carbon significantly absorbed the incoming short wave radiation in the atmosphere, a result that is consistent with previous studies. Pre-monsoon (March-April-May) rainfall showed positive anomalies, particularly for some coastal regions of India. The summer (June-July-August) rainfall anomalies were negative over the northern Himalayas, Myanmar, southern China and most of the regions below 20°N due to the decrease in temperature gradients induced by the absorption of BC aerosols. The vertical wind speed anomalies indicated that these regions experienced less convection, which reduces the precipitation efficiency of the monsoon system in South Asia.

Language(s): English

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Tags: Aerosols ; Atmosphere ; Climate ; Monsoon ; Acid rain ; Research ; Region II - Asia ; South East Asia Add tag

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Interannual Variability of Snow Depth over the Tibetan Plateau and Its Associated Atmospheric Circulation Anomalies

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Mao Jiang-Yu - Science Press, 2010

The interannual variability of wintertime snow depth over the Tibetan Plateau (TP) and related atmospheric circulation anomalies were investigated based on observed snow depth measurements and NCEP/NCAR reanalysis data. Empirical orthogonal function (EOF) analysis was applied to identify the spatio-temporal variability of wintertime TP snow depth. Snow depth anomalies were dominated by a monopole pattern over the TP and a dipole structure with opposite anomalies over the southeastern and northwestern TP. The atmospheric circulation conditions responsible for the interannual variability of TP s ...

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Interannual Variability of Snow Depth over the Tibetan Plateau and Its Associated Atmospheric Circulation Anomalies

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10047

Jiang-Yu Mao

in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.213-218

The interannual variability of wintertime snow depth over the Tibetan Plateau (TP) and related atmospheric circulation anomalies were investigated based on observed snow depth measurements and NCEP/NCAR reanalysis data. Empirical orthogonal function (EOF) analysis was applied to identify the spatio-temporal variability of wintertime TP snow depth. Snow depth anomalies were dominated by a monopole pattern over the TP and a dipole structure with opposite anomalies over the southeastern and northwestern TP. The atmospheric circulation conditions responsible for the interannual variability of TP snow depth were examined via regression analyses against the principal component of the most dominant EOF mode. In the upper troposphere, negative zonal wind anomalies over the TP with extensively positive anomalies to the south indicated that the southwestward shift of the westerly jet may favor the development of surface cyclones over the TP. An anomalous cyclone centered over the southeastern TP was associated with the anomalous westerly jet, which is conducive to heavier snowfall and results in positive snow depth anomalies. An anomalous cyclone was observed at 500 hPa over the TP, with an anomalous anticyclone immediately to the north, suggesting that the TP is frequently affected by surface cyclones. Regression analyses revealed that significant negative thickness anomalies exist around the TP from March to May, with a meridional dipole anomaly in March. The persistent negative anomalies due to more winter TP snow are not conducive to earlier reversal of the meridional temperature gradient, leading to a possible delay in the onset of the Asian summer monsoon.

Language(s): English

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Tags: Temperature anomaly ; Atmospheric circulation ; Snow ; Ozone ; Seasonal change ; China ; Tibet, China Add tag

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