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Solar release time of solar energetic particles and associated acceleration source in corona

Chinese Science Bulletin 2008年第2期53卷 161-168页

作者： LE GuiMing1,2.3,4, TANG YuHua1 & HAN YanBen4 1 Department of Astronomy, Nanjing University, Nanjing 2.0093, china 2.key {2. of Radiometric Calibration and Validation for Environmental Satellites, china meteorological Administration, beijing 100081, china 3 National Center for Space weather, china meteorological Administration, beijing 100081, china 4 National Astronomical Observatories, Chinese {12. of sciences, beijing 100012. china Department of Astronomy Nanjing University Nanjing China key laboratory of Radiometric Calibration and Validation for Environmental Satellites China Meteorological Administration Beijing China National Center for Space weather China Meteorological Administration Beijing China National Astronomical Observatories Chinese Academy of Sciences Beijing China

Solar energetic particles (SEPs) are accelerated in corona at an early phase of solar energetic particle events (SEPE). The acceleration mechanism of SEPs in corona can only be inferred from an analysis of multi-band observational data, as the observation of SEPs is usually made around 1AU. In this context, people have investigated spectrums, charge state, solar release time (SRT), and multi-band data of SEPEs, in an attempt to judge the acceleration mechanism of SEPs. The SRT computation of SEPs is an important and commonly used approach to study the acceleration mechanism of SEPs in corona. This paper reviews some important findings concerning the SRT computation of SEPs, and analyzes different merits of each approach for such calculation, based on a range of SEPE case studies. This paper also analyzes and discusses both possible and actual acceleration mechanisms of a number of SEPEs, by calculating the SRT of the SEPEs. Finally, the paper summarizes the possible problems in studying an acceleration mechanism of SEPEs inferred from the SRT of SEP.

关键词：阳光释放时间加速度电晕太阳耀斑

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Influence of atmospheric heat sources over the Tibetan Plateau and the tropical western North Pacific on the inter-decadal variations of the stratosphere-troposphere exchange of water vapor

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Science china Earth sciences 2008年第8期51卷 1179-1193页

作者： ZHAN RuiFen1,2.LI JianPing2.1Shanghai Typhoon Institute of china meteorological Administration,Shanghai 2.0030,{2. 2.3} key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics(LASG),Institute of Atmospheric Physics,Chinese academy of sciences,beijing 10002.,{2. Shanghai Typhoon Institute of china meteorological Administration Shanghai China state key {2. of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

This study investigates the Stratosphere-Troposphere Exchange(STE) of water vapor,emphasizes its interdecadal variations over Asia in boreal summer,and discusses the influences of atmospheric heat sources over the Tibetan Plateau and the tropical western North Pacific(WNP) on them by using the Wei method with reanalysis data from the European Centre for Medium-Range weather Forecasts(ECMWF) for the years of *** climatology shows that the upward transport of water vapor across the tropopause in boreal summer is the most robust over the joining area of the South Asian Peninsula and Indian-Pacific Oceans(defined as AIPO).The upward transport over there can persistently convey the abundant water vapor into the stratosphere and then influence the distribution and variation of the stratospheric water *** analysis shows that interdecadal variations of the water vapor exchange over the AIPO are significant,and its abrupt change occurred in the mid-1970s and the early *** these three periods,as important channels of the water vapor exchange,the effect of Bay of Bengal-East Asia as well as South china Sea was gradually weakening,while the role of the WNP becomes more and more *** studies show that atmospheric heat sources over the Tibetan Plateau and the WNP are two main factors in determining the interdecadal variations of water vapor *** thermal influences over the Tibetan Plateau and the WNP have been greatly adjusted over the pass 44 *** synthesis influences the interdecadal variations of the water vapor exchange by changing the Asian summer monsoon,but their roles vary with time and *** after 1992.the influence of heat source over the Tibetan Plateau remarkably weakens,while the heat source over the WNP dominates the across-tropopause water vapor *** have important implications for understanding the transport of other components in the atmosphere and estimating the impact of human activities(

关键词： Tibetan Plateau tropical western North Pacific atmospheric heat source STE inter-decadal variations

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Pollution characteristics of atmospheric fine particles and their secondary components in the atmosphere of Shenzhen in summer and in winter

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Science china Chemistry 2006年第5期49卷 466-474页

作者： NIU Yuwen1,2.HE Lingyan1,2.HU Min2.ZHANG Jing2.& ZHAO Yunliang2.1. Shenzhen Graduate School of Peking University,Shenzhen 518055,china 2. state Joint {2. laboratory of Environmental Simulation and Pollution Control,College of Environmental sciences,Peking University,beijing 100871,china Shenzhen Graduate School of Peking University Shenzhen China state Joint key {2. of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing China

Two field measurements for atmospheric fine particles were conducted in Baoan district of Shenzhen during the summer and winter in 2.04. Totally 30 sets of 2. h samples were collected, and then the mass concentrations and chemical compositions were determined. The seasonal varia- tions and secondary pollution characteristics of fine particles during the sampling periods were dis-cussed with meteorological factors. The results show that seasonal variations of atmospheric particles are significant in Shenzhen. The average mass concentrations of PM2.5 and PM10 in summer were 35 μg·m-3 and 57 μg·m-3, respectively, and those in winter were 99 μg·m-3 and 135 μg·m-3, respec-tively. The concentrations of both PM2.5 and PM10 in winter increased 184% and 137%, respectively, compared to those in summer. PM2.5 accounted for 61% and 75% of PM10 in summer and in winter, respectively, indicating severe fine particle pollution in Shenzhen. During the summer and winter sampling periods, the mean OC/EC ratios were 3.4 and 1.6, respectively. The estimated secondary organic carbon (SOC) averagely accounted for 56% and 6% of the total OC in summer and in winter, respectively, which implies a major contribution of SOC to OC in summer. During the continuous high temperature period in summer, both the concentrations and fractions of secondary aerosol compo-nents in PM2.5 were highly elevated, suggesting severe secondary pollution again. The prevailing wind was from South china Sea in summer, and the air quality was good. The prevailing wind in winter was from china's Mainland to the north, and the polluted air mass led to poor air quality.

关键词： PM2.5, mass concentration, secondary pollution, seasonal variation, Shenzhen.

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A novel approach in predicting non-stationary time series by combining external forces

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Science Bulletin 2011年第Z2期 3053-3056页

作者： WANG GeLi 1* , YANG PeiCai 1 , BIAN JianChun 1 & ZHOU XiuJi 2.3 1 laboratory for Middle Atmosphere and Glotal Environment Observation, Institute of Atmospheric Physics, Chinese academy of {2., beijing 10002., china 2.Chinese academy of meteorological {2., beijing 100081, china 3 state key laboratory of severe weather, beijing 100081, china

In this paper, we investigate a novel technique that reconstructs the observed time series and incorporates driving forces. Furthermore, to illustrate and test the technique, we consider a couple of predictive experiments using ideal time series provided by the logistic and Lorenz systems with specific driving forces. The preliminary results show this approach can improve prediction proficiency to some extent, and the external forces play a similar role to that of state variables.

关键词： driving force non-stationary system climate prediction time series prediction

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Changes in the spatial scale of beijing UHI and urban development

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Science china Earth sciences 2005年第Z2期48卷 116-127页

作者： YU Shuqiu, BIAN Lingen & LIN Xuechun state key {2. on severe weather, Chinese academy of meteorological sciences, beijing 100081, china National Climate Center, china meteorological Administration, beijing 100081, china state key {2. on severe weather Chinese Academy of Meteorological Sciences Beijing 100081 China National Climate Center China Meteorological Administration Beijing 100081 China

The seasonal and interannual variations of beijing urban heat island (UHI) are investigated in this paper using the temperature data from 1960 to 2.00 at 2. meteorological stations in the beijing region, and then the relationship between the intensity and spatial scale of UHI and beijing urbanization indices is analyzed and discussed. Main conclusions are the followings. First, beijing UHI shows obvious seasonal variations, and it is strongest in winter, next in spring and autumn, and least in summer. The seasonal variation of the UHI mainly occurs in the urban area. The UHI intensity at the center of beijing is more than 0.8℃ in winter, and only 0.5℃ in summer. Second, the intensity of beijing HUI exhibits a clear interannual warming trend with its mean growth rate (MGR) being 0.3088℃/10 a. The MGR of HUI is largest in winter, next in spring and autumn, and least in summer, and the urban temperature increase makes a major contribution to the growth of HUI intensity. Third, since the Reform and Opening, the urbanization indices have grown several ten times or even one hundred times, the intensity of HUI has increased dramatically, and its spatial scale also expanded distinctively along with the expansion of urban architectural complexes. Fourth, the interannual variation of urbanization indices is very similar with that of HUI intensity, and their linear correlation coefficients are significant at a more than 0.001 confidence level.

关键词： beijing region, temperature change, heat island effect, HUI spatial scale, human activities.

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Vertical dynamic and thermodynamic characteristics of urban lower boundary layer and its relationship with aerosol concentration over beijing

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Science china Earth sciences 2005年第Z2期48卷 25-37页

作者： ZHOU Mingyu, YAO Wenqing, XU Xiangde & YU Haiqing state key {2. on severe weather, Chinese academy of meteorological sciences, beijing 100081, china National Marine Environment Forecasting Center, beijing 100081, china National meteorological Center, beijing 100081, china state key {2. on severe weather Chinese Academy of Meteorological Sciences Beijing 100081 China National Marine Environment Forecasting Center Beijing 100081 China state key {2. on severe weather Chinese Academy of Meteorological Sciences Beijing 100081 China National meteorological Center Beijing 100081 China

By utilizing observational data from a 32. m tower of the Institute of Atmospheric Physics (IAP), Chinese academy of sciences (CAS) on March 19-2., 2.01 and August 11-2., 2.03, a comprehensive study was conducted on the vertical dynamical and thermodynamic characteristics of the urban lower boundary layer (ULBL) and its relationship with aerosol concentration over {2.. Firstly, a comparative analysis was made on the gradient data (wind, temperature and humidity), ultrasonic data (atmospheric turbulences) and air-quality observations at different tower heights (47, 12. and 2.0 m). Secondly, a diagnosis was made to reveal the major features of normalized variances of velocity and temperature, turbulence kinetic energy as well as their relationship with aerosol concentrations. Furthermore, the characteristics of the ULBL vertical structure and the TSP concentration/distribution variations during a sand/dust weather process were also analyzed. The outcome of the study showed that under unstable stratification, the normalized variances of velocity (σu/u*, σv/u*, σw/u*) and temperature (σT/T*) at 47 and 12. m heights fit the Monin-Obukhov similarity (MOS) framework and the fitting formulas were given out accordingly. According to the stratification parameter (z′/L), the stable ULBL could be divided into 2.zones. With z′/L0.1 and the normalized velocity variances tended to increase along with higher stability, but it remained constant for normalized temperature variances. At daytime, the near-surface layer includes two heights of 47 and 12. m, while 2.0 m has been above it. The ULBL analysis in conjunction with a sand/dust weather process in {2. in March 2.01 indicated that the maximum concentration of Total Suspended Particulates (TSP) at 32. m reached 913.3 μg/m3 and the particles were transported from the upper to lower ULBL, which was apparently rela

关键词： urban boundary layer, turbulence, aerosol concentration, sand/dust weather.

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Three-year changes of surface albedo of degraded grassland and cropland surfaces in a semiarid area

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Chinese Science Bulletin 2008年第8期53卷 1246-1254页

作者： LIU HuiZhi1↑, TU Gang2.3 & DONG WenJie4 1 state key {2. of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chi- nese academy of sciences, beijing 10002., china 2.{2. of Research for Middle-High Latitude Circulation System and East Asia Monsoon, china meteorological Administration, Changchun 130062. china 3 Institute of meteorological Science of Jilin Province, Changchun 130062. china 4 National Climate Center, beijing 100081, china state key {2. of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China laboratory of Research for Middle-High Latitude Circulation System and East Asia Monsoon China Meteorological Administration Changchun China Institute of meteorological Science of Jilin Province Changchun China National Climate Center Beijing China

Diurnal, seasonal and interannual variations of surface albedo of degraded grassland and cropland surfaces at a semiarid area of Tognyu have been investigated based on the continuous three years observational data from 2.03 to 2.05. The changes of surface albedo with solar elevation angle and soil moisture have been discussed also. It has been found that surface albedo has almost the same diurnal and seasonal variations on degraded grassland and cropland surfaces in the semiarid area, while sur- face albedo is large in winter and small in summer. The diurnal variation of the surface albedo has re- lationship with the weather condition. The diurnal cycle of the surface albedo likes the "U" shape curve in sunny day, while it is low-high after the rain, and high-low after the snow. The surface albedo has large variation in cloudy day, while it has no any variation in overcast day. The large difference of the surface albedo can be 0.04 in winter between two land surfaces, because the snow has large effects on the surface albedo in winter. The rainfall is an important factor in summer on the surface albedo, while the difference of the surface albedo is 0.01 only between two land surfaces. The differences of the surface albedo can also be 0.04 in autumn due to vegetation growing. The seasonal-average surface albeo from 2.03―2.05 is 0.2., 0.2., 0.2., 0.32.respectively in spring, summer, autumn and winter on the degraded grassland surface,while it is 0.2., 0.2., 0.2., 0.33 respectively in spring, summer, autumn and winter on the cropland surface. The surface albedo becomes smaller with the increase of solar elevation angle. When the solar elevation angle is greater than 40°, the surface albedo changes very little and tends to be a constant. The surface albedo has negative exponent functions with soil moisture in the growing season.

关键词：半干旱地区表面反照率土壤湿度草地退化

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Assessment of Dust Aerosol Optical Depth and Shortwave Radiative Forcing over the Northwest Pacific Ocean in Spring Based on Satellite Observations

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Atmospheric and Oceanic Science Letters 2009年第4期 223-228页

作者： CHEN Lin 1,2.SHI Guang-Yu 1,ZHONG Ling-Zhi 3,and TAN Sai-Chun 1 1 state key {2. of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese academy of sciences,beijing 10002.,china 2.key {2. of Radiometric Calibration and Validation for Environmental Satellites (KLRCV),National Satellite Meteorology Center,china meteorological Administration (NSMC/CMA),beijing,100081,china 3 state key {2. of severe weather,Chinese academy of meteorological sciences,beijing 100081,china state key {2. of Numerical Modeling for Atmospheric sciences and Geophysical FluidDynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beo＇ing 100029 China key laboratory of Radiometric Calibration and Validation for Environmental Satellites （KLRCV） National Satellite Meteorology Center China Meteorological Administration （SMC/CMA） Beijing 100081 China state key {2. of severe weather Chinese Academy of Meteorological Sciences Beijing 100081 China

Dust aerosol optical depth (AOD) and its ac-companying shortwave radiative forcing (RF) are usually simulated by numerical ***,by using 9 months of Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol product data in combination with Clouds and the Earth’s Radiant Energy System Single Scanner Footprint (CERES/SSF) data,dust AOD and its shortwave RF were estimated over the cloud-free north-west (NW) Pacific Ocean in the springs of 2.04,2.05,and *** results showed that in this region,the mean dust AOD and its shortwave RF were 0.10 and 5.51 W m 2.*** order to validate the dust AOD de-rived by MODIS,results from the Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model were also used *** correlation coefficient between the monthly averaged dust AOD derived by MODIS measurements and the model simulation results was approximately *** the estimates of the dust AOD and its shortwave RF obtained in this study are based mainly on satellite data,they offer a good reference for numerical models.

关键词： dust aerosols optical depth shortwave radiative forcing northwest Pacific satellite measurements

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Analysis to significant climate change in aerosol influence domain of beijing and its peripheral areas by EOF mode

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Science china Earth sciences 2005年第Z2期48卷 246-261页

作者： SHI Xiaohui, XU Xiangde, ZHANG Shengjun & DING Guoan state key {2. of severe weather, Chinese academy of meteorological sciences, beijing 100081, china Nanjing University of Information Science and Technology, Nanjing 2.0044, china state key {2. of severe weather Chinese Academy of Meteorological Sciences Beijing 100081 China Nanjing University of Information Science and Technology Nanjing 210044 China state key {2. of severe weather Chinese Academy of Meteorological Sciences Beijing 100081 China

Using the total ozone mapping spectrometer (TOMS) aerosol optical depth (AOD) data and the sunshine duration, fog days, low cloud cover (LCC), etc. meteorological data in 1979-2.00 in North china, as well as empirical orthogonal function (EOF) mode statistical analyses method, the winter aerosol distributive character of {2. and peripheral city agglomeration and its influence effect on regional climate are investigated in this paper, especially the relation between aerosol influence effect and distinct change regions of eigenvectors of EOF mode. It is found from analyzing the regional distribution of the long-term averaged winter TOMS AOD that there is a large-scale relatively stable high value zone of aerosol concentration in the valley of the {2. and peripheral U-shape megarelief. A high correlation area of AOD between {2. and its southern peripheral exists in winter, and in this significant region of aerosol interaction, there is 'in-phase' character of the interannual variations of winter AOD, fog days, and LCCs. It indicates that the variations of aerosol in {2. and its peripheral areas have impacts on interannual changes of fog days and LCCs in this area. The EOF analyses of the meteorological data further reveal the climate change regions and long-term trends of winter sunshine duration-reducing, and LCC- and fog days-increasing in North china. The areas of significant changes of the first EOF eigenvectors (FEE) of sunshine duration, fog days, LCCs almost superpose on corresponding marked regions of interdecadal differences between the 1990s and 1980s, and all accord with the S-N zonal high value pattern and high correlation region of winter AOD in {2. and its peripheral areas. Interannual variations of their associated time coefficients (ATC) are in phase with that of regional mean AOD, and both of them have a secular rising trend. Results by EOF mode analyses depict the regional climatic change principal character of winter sunshine dura

关键词： city agglomeration, aerosol, climatic effect, EOF mode, influence domain.

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Typhoon Cloud Image Enhancement by Fuzzy Technique

Typhoon Cloud Image Enhancement by Fuzzy Technique

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第2.届中国气象学会年会灾害天气事件的预警、预报及防灾减灾分会场

作者： Changjiang Zhang1,2. Juan LU1 (1. College of Mathematics, Physics and Information Engineering, Zhejiang Normal University, Jinhua, china 32.004 2. state {2. laboratory of severe weather, Chinese academy of meteorological sciences, beijing, china 100081)

A new kind of image measure function is proposed by combing fuzzy theory with other some measures. We use it as the overall fitness function of genetic algorithm to adaptively optimize the nonlinear transform parameters in the nonlinear transform function. Thus an optimal gray transformation curve is obtained to enhance the region of interest for a typhoon cloud image. Experimental results show that the proposed method has higher adaptability and intelligence. The proposed method is better than the classical image enhancement methods in overall performance. Enhanced typhoon cloud images by the proposed method can be used to accurately locate the center and predict intensity of the typhoon.

关键词： typhoon cloud image enhancement genetic algorithm fuzziness

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