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A Modeling Study of Seasonal Variation of Atmospheric Aerosols over east asia

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Advances in Atmospheric Sciences 2012年第1期29卷 101-117页

作者：李嘉伟韩志伟 Key laboratory of regional climate-environment Research for temperate east asia Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029

In this study, a regional air quality model system （RAQMS） was applied to investigate the spatial distributions and seasonal variations of atmospheric aerosols in 2006 over east asia. Model validations demonstrated that RAQMS was able to reproduce the evolution processes of aerosol components reasonably well. Ground-level PM10 （particles with aerodynamic diameter ≤10 μm） concentrations were highest in spring and lowest in summer and were characterized by three maximum centers： the Taklimakan Desert （-1000 μg m^-3）, the Gobi Desert （-400 μg m^-3）, and the Huabei Plain （- 300 μg m^-3） of China. Vertically, high PM10 concentrations ranging from 100 μg m-3 to 250 μg m-3 occurred from the surface to an altitude of 6000 m at 30°-45°N in spring. In winter, the vertical gradient was so large that most aerosols were restricted in the boundary layer. Both sulfate and ammonium reached their highest concentrations in autumn, while nitrate reached its maximum level in winter. Black carbon and organic carbon aerosol concentrations reached maximums in winter. Soil dust were strongest in spring, whereas sea salt exerted the strongest influence on the coastal regions of eastern China in summer. The estimated burden of anthropogenic aerosols was largest in winter （1621 Gg） and smallest in summer （1040 Gg）. The sulfate burden accounted for -42% of the total anthropogenic aerosol burden. The dust burden was about twice the anthropogenic aerosol burden, implying the potentially important impacts of the natural aerosols on air quality and climate over east asia.

关键词： east asia aerosol components model simulation spatial distribution seasonal variation,column burden

Characteristics of Elemental Composition of PM_(2.5) in the Spring Period at Tongyu in the Semi-arid Region of Northeast China

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Advances in Atmospheric Sciences 2008年第6期25卷 922-931页

作者：张仁健符淙斌韩志伟朱崇抒 Key laboratory of regional climate-environment Research for temperate east asia Institute of Atmospheric Physics Chinese Academy of Sciences START Regional Center for Temperate East Asia SKLLQG Institute of Earth Environment Chinese Academy of Sciences

Continuous observations of mass concentration and elemental composition of aerosol particles （PM2.5） were conducted at Tongyu, a semi-arid site in Northeast China in the spring of 2006. The average mass concentration of PM2.5 at Tongyu station was 260.9±274.4 μg m^-3 during the observation period. Nine dust events were monitored with a mean concentration of 528.0±302.7 μgm^-3. The PM2.5 level during non- dust storm （NDS） period was 111.65±63.37 μg m^-3. High mass concentration shows that fine-size particles pollution was very serious in the semi-arid area in Northeast China. The enrichment factor values for crust elements during the dust storm （DS） period are close to those in the NDS period, while the enrichment factor values for pollution elements during the NDS period are much higher than those in the DS period, showing these elements were from anthropogenic sources. The ratios of dust elements to Fe were relative constant during the DS period. The Ca/Fe ratio in dust aerosols at Tongyu is remarkably different from that observed in other source regions and downwind regions. Meteorological analysis shows that dust events at Tongyu are usually associated with dry, low pressure and high wind speed weather conditions. Air mass back-trajectory analysis identified three kinds of general pathways were associated with the aerosol particle transport to Tongyu, and the northwest direction pathway was the main transport route.

关键词： dust aerosol mass concentration elemental composition transport pathway

Multimodel Ensemble Forecasts for Precipitations in China in 1998

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Advances in Atmospheric Sciences 2008年第1期25卷 72-82页

作者：柯宗建董文杰张培群 Key laboratory of regional climate-environment for temperate east asia Institute of Atmospheric Physics Chinese Academy of Sciences laboratory for climate Studies National Climate Center China Meteorological Administration

Different multimodel ensemble methods are used to forecast precipitations in China, 1998, and their forecast skills are compared with those of individual models. Datasets were obtained from monthly simulations of eight models during the period of January 1979 to December 1998 from the “climate of the 20th Century Experiment” （20C3M） for the Fourth IPCC Assessment Report. climate Research Unit （CRU） data were chosen for the observation analysis field. Root mean square （RMS） error and correlation coeffi-cients （R） are used to measure the forecast skills. In addition, superensemble forecasts based on different input data and weights are analyzed. Results show that for original data, superensemble forecasting based on multiple linear regression （MLR） performs best. However, for bias-corrected data, the superensemble based on singular value decomposition （SVD） produces a lower RMS error and a higher R than in the MLR superensemble. It is an interesting result that the SVD superensemble based on bias-corrected data performs better than the MLR superensemble, but that the SVD superensemble based on original data is inferior to the corresponding MLR superensemble. In addition, weights calculated by different data formats are shown to affect the forecast skills of the superensembles. In comparison with the MLR superensemble, a slightly significant effect is present in the SVD superensemble. However, both the SVD and MLR superensembles based on different weight formats outperform the ensemble mean of bias-corrected data.

关键词： precipitation multimodel ensemble China

Comparisons of urban-related warming in Beijing using different methods to calculate the daily mean temperature

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Science China Earth Sciences 2019年第4期62卷 693-702页

作者： Deming ZHAO Jian WU CAS Key laboratory of regional climate-environment for temperate east asia Institute of Atmospheric PhysicsChinese Academy of Sciences Department of Atmospheric Science Yunnan University

To evaluate the contribution of urban surface expansion to regional warming using different methods to calculate the daily mean surface air temperature(SAT), satellite-based images displaying urban surface expansion over the past 37 years(1980–2016) across China were collected for use in nested numerical experiments using the weather research and forecasting(WRF) regional climate model. The contribution of urban surface expansion to urban-related warming was determined using the daily mean SAT averages based on four time records each day(00, 06, 12, and 18 h UTC, T_4) and averages of the SAT maximum(Tmax) and minimum(Tmin)(Txn). The contribution of urban surface expansion to urban-related warming(relative value) in Beijing was 0.110°C per decade(22.8% of total warming) for T_4 and 0.094°C per decade(20.2%) for Txn. The values obtained when using T_4 were larger than those obtained when using Txn. Differences in the urban-related warming calculated using T_4 and Txncould be attributed to the smaller changing trends in Txnin the urban-surface expansion experiment, which resulted from a large changing trend in Tminand a much smaller changing trend in Tmax. The changes in the diurnal cycle of the energy budget due to urban surface expansion induced changes in the diurnal cycle of SAT, as evidenced by the four time records each day, as well as Tmaxand Tmin. This was especially true for periods of intense urban surface expansion, although the annual mean SAT calculated using Txnwas larger than that calculated using T_4. The increase in impervious area(walls, streets, etc.) due to urban surface expansion, as well as the widespread use of building materials with a large heat capacity resulted in a marked increase in ground heat flux in the daytime. This restricted the increase in SAT in the daytime, but promoted it at night. The increases in SAT due to urban surface expansion were not symmetrical, being smaller in the daytime and larger at night.

关键词： Urban surface expansion Surface air temperature Daily mean temperature Changing trend Urban-related warming

Correlations between North Atlantic Oscillation Index in winter and eastern China Flood/Drought Index in summer in the last 530 years

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Chinese Science Bulletin 2005年第21期50卷 2505-2516页

作者： FU Congbin & ZENG Zhaomei Key laboratory of regional climate-environment for temperate east asia, Institute of Atmospheric Physics, Chinese Academy of Sciences START regional Center for temperate east asia, Beijing 100029, China Key laboratory of regional climate-environment for temperate east asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China START regional Center for temperate east asia Beijing 100029 China

The time series of winter North Atlantic Oscil-lation Index (NAOI) in the period of 1429-1983 developed by Glueck and summer Flood/Drought Index (FDI) of eastern China in the period of 1470-1999 from 100 stations are used in this paper to study the potential impact of North Atlantic Oscillation on the climate in China. The analysis has ex-plored some significant lag correlations between FDI and NAOI. The maximum positive correlation coefficients be-tween NAOI and area-mean FDI in eastern and northern China lagging 2-3 years reach at 0.001 significance level, and while there are also negative correlation between NAOI and FDI in central and southern China at significance level of 0.05-0.01. The correlation between FDI and NAOI is time-dependent, i.e. the correlation coefficients between two indices vary from period to period. The highest correlation appeared in the period of 1636-1742, around the Little Ice Age, with the significant level of far above 0.001. The second significant period was from 1951 to 1999, at the level of 0.005-0.002. Both the power spectrum analysis and Morlet wavelet transformation have presented an interesting phe-nomenon: the area-mean FDIs in eastern and northern China share almost the same oscillation periods with NAOI in the inter-annual, decadal and centurial scales’ oscillations, i.e. 4-5, about 10, 20-30, around 50 and 80-100 years, etc. The Mann-Kendall Rank Statistic test reveals the significant trend and decadal abrupt changes in the series of area-mean FDIs in eastern and northern China in the past 530 years, while the NAOI in the past 400 years, did not show such trend at the significance level, but presented more frequent changes than those of FDI in China. This difference is per-haps due to the fact that the amplitude of the extremes of reconstructed NAOI series is less than that from instrumen-tal records.

关键词：中国洪水干旱气候变化大西洋振动系数

Analysis of precipitation characteristics of South and North China based on the power-law tail exponents

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Chinese Physics B 2008年第7期17卷 2745-2752页

作者：封国林龚志强支蓉章大全 Department of Physics Yangzhou University Key laboratory of regional climate-environment for temperate east asia Institute of Atmospheric PhysicsChinese Academy of Sciences laboratory for climate Studies National Climate CenterChina Meteorological Administration

Precipitation sequence is a typical nonlinear and chaotic observational series, and studies on precipitation forecasts are restricted to the use of traditional linear statistical methods, especially when analysing the regional characteristics of precipitation. In the context of 20 stations＇ daily precipitation series （from 1956 to 2000） in South China （SC） and North China （NC）, we divide each precipitation series into many self-stationary segments by using the heuristic segmentation algorithm （briefly BG algorithm）. For each station＇s precipitation series, we calculate the exponent of power-law tall （EPT） of the cumulative probability distribution of segments with a length larger than l for precipitation and temperature series. Our results show that the power-law decay of the cumulative probability distribution of stationary segments might be a common attribution for precipitation and other nonstationary time series; the EPT somewhat indicates the precipitation duration and its spatial distribution that might be different from area to area. The EPT in NC is larger than in SC; Meanwhile, EPT might be another effective way to study the abrupt changes in nonlinear and nonstationary time series.

关键词： the power-law exponents precipitation durative abrupt precipitation change

Intercomparison of the Summertime Subtropical High from the ERA-40 and over east Eurasia and the western North Pacific

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Advances in Atmospheric Sciences 2009年第2期26卷 119-131页

作者：赵天保符淙斌 Global Change System for Analysis Research and Training regional Center for temperate east asia Key laboratory of regional climate-environment Research for the temperate east asiaInstitute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029

An intercomparison of summertime （JJA）subtropical geopotential heights from the ERA-40 and NCEP/NCAR reanalysis is specifically conducted over east Eurasia and the western North Pacific. The NCEP/NCAR is obviously lower than the ERA-40 in the mid-to-lower troposphere in most regions of east Eurasia before the mid-1970s, but becomes higher than the ERA-40 after the mid-1970s and thus demonstrates stronger increased trends during the period of 1958-2001. Both reanalyses are lower than the observations in most regions of China. The NCEP/NCAR especially shows tremendously systematic lower values before the mid-1960s and displays abrupt changes before the 1970s. Several indices of the western North Pacific subtropical high （WNPSH）, calculated from both reanalyzed summer geopotential heights, also reveal that the variation trend of the NCEP/NCAR is stronger than that of the ERA-40 in the mid-to-lower troposphere from 1958 to 2001. Through singular value decomposition （SVD） analysis, the summer geopotential heights at 500 hPa from the ERA-40 are better than the NCEP/NCAR counterparts at interacting with the precipitation over the east asian monsoon region. The results indicate that the NCEP/NCAR in the mid-and-lower troposphere may overestimate interdecadal changes and should be used cautiously to study the relationship between the WNPSH and precipitation ove ther east asia Monsoon region before the mid-1970s.

关键词： summertime subtropical high reanalysis comparison and analysis

Some evidence of drying trend over northern China from 1951 to 2004

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Chinese Science Bulletin 2006年第23期51卷 2913-2925页

作者： MA Zhuguo1,2 & FU Congbin1,2 1. Key laboratory of regional climate-environment for temperate east asia, Chinese Academy of Sciences, Beijing 100029, China 2. START regional Center for temperate east asia, Institute of Atmos-pheric Physics, Chinese Academy of Sciences, Beijing 100029, China Key laboratory of regional climate-environment for temperate east asia Chinese Academy of Sciences Beijing China START regional Center for temperate east asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The surface wetness index, Palmer drought sererity index and the retrieval of soil moisture over China were calculated using monthly precipitation and monthly mean surface air temperature. Based on the contrast analysis of the variation of the above three indices and precipitation, the dry/wet spatio-temporal pattern of northern China in the last 54 years was revealed, and the evidence of drying trend over northern China was analyzed, especially. The results show the following four facts: (1) The drying trend is the main characteristic of the eastern part of Northwest China and the central part of North China since the 1980s and it was enhanced in the last 15 years mainly due to the precipitation decrease and the temperature increase; (2) During the last 54 years, there was only one dry/wet shift at the interdecadal scale occurring in the eastern part of Northwest China and the central part of North China in the late 1970s, which was related to 1977/1978 global abrupt change, whereas there were three shifts in Northeast China, one was in the mid 1990s and the other two were in 1965 and 1983, respectively; (3) Unlike the variation trend of other subregions of northern China, the western part of Northwest China is currently located in a relatively wetting period, which is weak-ened due to the temperature increase; (4) The extreme drought frequency is obviously increasing in the eastern part of Northwest China, the central part of North China and Northeast China since the 1980s, which is closely related to the precipitation decrease and temperature increase in these subregions.

关键词：中国北方干燥趋向干旱索引气候背景

Sensitivity of Potential Evapotranspiration Estimation to the Thornthwaite and Penman–Monteith Methods in the Study of Global Drylands

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Advances in Atmospheric Sciences 2017年第12期34卷 1381-1394页

作者： Qing YANG Zhuguo MA Ziyan ZHENG Yawen DUAN Key laboratory of regional climate–environment for temperate east asia Institute of Atmospheric PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences

Drylands are among those regions most sensitive to climate and environmental changes and human-induced *** most widely accepted definition of the term dryland is a ratio,called the Surface Wetness Index(SWI),of annual precipitation to potential evapotranspiration(PET)being below *** is commonly estimated using the Thornthwaite(PET Th)and Penman–Monteith equations(PET PM).The present study compared spatiotemporal characteristics of global drylands based on the SWI with PET Th and PET *** showed vast differences between PET Th and PET PM;however,the SWI derived from the two kinds of PET showed broadly similar characteristics in the interdecadal variability of global and continental drylands,except in North America,with high correlation coefficients ranging from 0.58 to *** was found that,during 1901–2014,global hyper-arid and semi-arid regions expanded,arid and dry sub-humid regions contracted,and drylands underwent interdecadal *** was because precipitation variations made major contributions,whereas PET changes contributed to a much lesser ***,distinct differences in the interdecadal variability of semi-arid and dry sub-humid regions were *** indicated that the influence of PET changes was comparable to that of precipitation variations in the global dry–wet transition ***,the contribution of PET changes to the variations in global and continental drylands gradually enhanced with global warming,and the Thornthwaite method was found to be increasingly less applicable under climate change.

关键词： potential evapotranspiration global drylands Thornthwaite Penman–Monteith