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GIS-based analysis of forest degradations in Baihe Forestry Bureau,northeast china

Science china(Technological sciences) 2006年第z1期49卷 167-176页

作者： ZHOU Li, DAI Limin , Guofan Shao, XU Dong, WANG Hui & BAI Jianwei Institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, china Graduate University of chinese academy of sciences, beijing 100101, china Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA Department of City Development, Jinan University, Jinan 250002, china academy of Forest Inventory and Planning, State Forestry administration, beijing 100714, china Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China

Forests in the Changbai Mountains are important timber sources for economic development of the society and provide ecological services in northeast china. In order to strengthen forest resource management, this paper analyzed management-induced changes in forest structure, tree species composition and forest landscape pattern from 1987 to 2000 for Baihe Forestry Bureau in Jilin Province based on digitized forest parcel maps and forest survey data. The results suggested that the area of Mature, High-Stocking, and Close-Canopy Forests decreased by 31.4%, 55.9% and 10.7% respectively; volume of Mixed Forest, the native forest vegetation type, decreased by 17.8%;the number of patches increased tremendously but the mean patch density decreased sharply for Mature, High-Stocking, Close-Canopy, and Mixed Forests. All the changes in forest structure, species composition, and landscape pattern indicated severe degradations going on with the forests in Baihe Forestry Bureau. Because of the effect of degradation to forest services, restoring forest resources and protecting biodiversity has become urgently important. The strategies of sustainable forest management need to be worked out and implemented.

关键词： geographic information system, forest management, Changbai Mountains, forest change, forest decline.

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THE ALTERNATE-SEASONAL CORRELATION OF LONG—RANGE WEATHER PROCESS

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Acta meteorologica Sinica 1992年第4期6卷 462-469页

作者： Lin Xuechun Zhang Ruixue chinese academy of meteorological sciences,beijing 100081

In this paper,the correlation of meteorological elements at an interval of 5—7 months,i.e.,the alternate-seasonal correlation,is thoroughly *** results show that the alternate-seasonal correlation is an important phenome- non in the long-range weather process,and it has a significant latitude effect and seasonal ***,the relation between this phenomenon and SST in the North Pacific is discussed.

关键词： alternate-seasonal correlation circulation characteristics Pacific temperature index(PTI)

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标准传递中日射表光谱误差的模拟计算

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太阳能学报 1996年第3期17卷 226-230页

作者：王炳忠中国气象科学研究院

工作直接日射表一般都有窗口，而标准直接日射表却没有窗口。校准时，由于窗口都有一定的波长范围，必然会截去部分日射，利用ＬＯＷＴＲＡＮ６对其影响进行了光谱模拟计算。结果表明，石英玻璃窗口的影响不大，相对误差一般均在±１％... 详细信息

工作直接日射表一般都有窗口，而标准直接日射表却没有窗口。校准时，由于窗口都有一定的波长范围，必然会截去部分日射，利用ＬＯＷＴＲＡＮ６对其影响进行了光谱模拟计算。结果表明，石英玻璃窗口的影响不大，相对误差一般均在±１％以内；如果采用ＷＧ２９５窗口，则其影响不容忽视。利用ＬＯＷＴＲＡＮ６并配合Ｉｑｂａｌ方法，对总日射表进行类似的研究表明，窗口对总日射表的影响不像直接日射表那样明显，相对误差一般均不超过±１％。根据光谱计算结果，认为与分光总日射表配合使用的总日射表在校准时，作一标准用的直接日射表应加上ＷＧ２９５窗口，以便与其它分光总日射表的长波端的截止波长一致，否则将会引起１－２％的系统误差。

关键词：辐射表窗口模拟计算光谱误差太阳辐射

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Distinguished Effects of Interannual Salinity Variability on the Development of the Central-Pacific El Ni o Events

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Atmospheric and Oceanic Science Letters 2012年第2期5卷 123-127页

作者： ZHENG Fei 1,WAN Li-Ying 2,and WANG Hui 3 1 International Center for Climate and Environment Science (ICCES),Institute of Atmospheric Physics,chinese academy of sciences,beijing 100029,china 2 Key Laboratory of Research on Marine Hazards Forecasting,National Marine Environmental Forecasting Center,beijing 100081,china 3 National meteorological Center,beijing 100081,china International Center for Climate and Environment Science (ICCES) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Key Laboratory of Research on Marine Hazards Forecasting National Marine Environmental Forecasting Center Beijing 100081 China National meteorological Center Beijing 100081 China

El Nio events in the central equatorial Pacific (CP) are gaining increased attention,due to their increasing intensity within the global warming *** physical processes have been identified in the climate system that can be responsible for the modulation of El Nio,especially the effects of interannual salinity *** this work,a comprehensive data analysis is performed to illustrate the effects of interannual salinity variability using surface and subsurface salinity fields from the Met Office ENSEMBLES (EN3) quality controlled ocean *** is demonstrated that during the developing phase of an El Nio event,a negative sea surface salinity (SSS) anomaly in the western-central basin acts to freshen the mixed layer (ML),decrease oceanic density in the upper ocean,and stabilize the upper *** related oceanic processes tend to reduce the vertical mixing and entrainment of subsurface water at the base of the ML,which further enhances the warm sea surface temperature (SST) anomalies associated with the El Nio ***,the effects of interannually variable salinity are much more significant during the CP-El Nio than during the eastern Pacific (EP) El Nio,indicating that the salinity effect might be an important contributor to the development of CP-El Nio events.

关键词： salinity effect CP-E1 Nifio EN3 dataset

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Approximation of dense-n/2-subgraph and table compression problems

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Science china Mathematics 2005年第9期48卷 1223-1233页

作者： XU Dachuan~1 HAN Jiye~2 & DU Dongle~3 1. College of Applied sciences,beijing University of Technology,beijing 100022,china 2. Institute of Applied Mathematics,academy of Mathematics and Systems Science,chinese academy of sciences,beijing 100080,china 3. Faculty of administration,University of New Brunswick,P.O.Box 4400,Fredericton,NB E3B 5A3,Canada College of Applied sciences Beijing University of Technology Beijing 100022 China Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China Faculty of administration University of New Brunswick P.O. Box 4400 Fredericton NB E3B 5A3 Canada

We develop improved approximation algorithms for two NP-hard problems: the dense-n/2-subgraph and table *** on SDP relaxation and advanced rounding techniques,we first propose 0. 5982 and 0. 5970-approximation algorithms respec- tively for the dense-n/2-subgraph problem (DSP) and the table compression problem (TCP). Then we improve these bounds to 0. 6243 and 0. 6708 respectively for DSP and TCP by adding triangle inequalities to strengthen the SDP *** results for TCP beat the 0. 5 bound of a simple greedy algorithm on this problem,and hence answer an open question of Anderson in an affirmative way.

关键词： dense-n/2-subgraph problem(DSP) table compression problem(TCP) SDP approximation ratio

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基于SSM/I被动微波数据的中国积雪深度遥感研究

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山地学报 2008年第1期26卷 59-64页

作者：延昊张佳华中国气象局国家气象中心中国气象科学研究院

通过对积雪和其他地物的被动微波辐射计SSM/I的微波亮温进行波谱分析,提出了一个识别积雪的SSM/I微波检测方法,与MODIS的5d合成积雪范围数据进行了比较,结果表明SSM/I的积雪范围与MODIS基本一致。对提出的SSM/I的微波积雪深度反演方法... 详细信息

通过对积雪和其他地物的被动微波辐射计SSM/I的微波亮温进行波谱分析,提出了一个识别积雪的SSM/I微波检测方法,与MODIS的5d合成积雪范围数据进行了比较,结果表明SSM/I的积雪范围与MODIS基本一致。对提出的SSM/I的微波积雪深度反演方法进行了验证,与2006年冬季每日的中国地面积雪深度观测数据的相关系数R的平方为0.46～0.54,偏差为-0.3～0.8cm,均方根误差rmse为4.4～6.8cm。

关键词：积雪识别积雪深度被动微波辐射计SSM/I MODIS

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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 Laboratory 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 Laboratory on Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China National Marine Environment Forecasting Center Beijing 100081 China State Key Laboratory on Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China National meteorological Center Beijing 100081 China

By utilizing observational data from a 325 m tower of the Institute of Atmospheric Physics (IAP), chinese academy of sciences (CAS) on March 19-29, 2001 and August 11-25, 2003, 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 beijing. 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, 120 and 280 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 120 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 120 m, while 280 m has been above it. The ULBL analysis in conjunction with a sand/dust weather process in beijing in March 2001 indicated that the maximum concentration of Total Suspended Particulates (TSP) at 320 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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Vertical distribution of ozone in the planetary boundary layer at the Ming Tombs, beijing

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Science china Earth sciences 2005年第S2期48卷 55-63页

作者： ZHENG Xiangdong, DING Guoan, YU Haiqing, LIU Yu & XU Xiangde chinese academy of meteorological sciences, Center for Atmospheric Watch and Service, Key Laboratory of Atmospheric Chemistry, china meteorological administration, beijing 100081, china chinese academy of meteorological sciences Center for Atmospheric Watch and Service Key Laboratory of Atmospheric Chemistry China Meteorological Administration Beijing 100081 China

Surface ozone (O3) and vertical O3 distribution in the planetary boundary layer (PBL) at the Ming Tombs (40°17’15"N, 116°12’51"E), beijing during September 7-12, 2001 were measured by ground based measurements and an in-situ tethersonde system. The results indicated that O3 concentration measured at surface level agreed well with that measured by tethersonde system in daytime when active thermal mixing was dominated. Ozone showed the lowest concentration before the sunrise and then gradually increased in the morning and reached the maximum in the afternoon 14:00-17:00 (Ist). After sunset, O3 gradually decreased and resulted in low value below 200-300 m due to surface loss processes and chemical destruction in stable boundary layer characterized by temperature inversions. High O3 was observed whenever there was pollutants transport from the metropolitan areas of beijing. Our analysis suggested the complex terrain of the Ming Tombs region caused pollutants transported from beijing to accumulate in the PBL, and resulted in severe O3 pollution, with a maximum over 160×10-9, when the synoptic conditions was favorable for photochemical O3 production.

关键词： O3 planetary boundary layer beijing.

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The boundary layer characteristics in the heavy fog formation process over beijing and its adjacent areas

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Science china Earth sciences 2005年第Z2期48卷 88-101页

作者： ZHANG Guangzhi, BIAN Lingeng, WANG Jizhi, YANG Yuanqin, YAO Wenqing & XU Xiangde HWL of chinese academy of meteorological sciences, beijing 10008, china National meteorological Center, beijing 100081, china HWL of chinese academy of meteorological sciences Beijing 10008 China National meteorological Center Beijing 100081 China

By utilizing the Atmospheric Boundary Layer (ABL) observational data made available from the project "973" under the auspices of the Ministry of Science and Technology of the People's Republic of china - entitled the beijing City Air Pollution Observation Field Experiment (BECAPEX), including the measurements by a wind profiler, captive airships, tower-based boundary layer wind and temperature gradient observational instruments (ultrasonic anemometers and electronic thermometers), air composition samplers, conventional upper-air, surface and Automatic Weather Stations (AWS) observations, this paper herewith analyzes, in a comprehensive manner, the occurrence of a heavy fog event over beijing in February 2001, including its formation, development, persistence, dynamic and thermodynamic features as well as evolving stratification structures within the boundary layer at different stages. The results suggested: (i) as a typical case of urban heavy fog, before the fog onset over beijing, a temperature inversion existed in the lower atmosphere, the smokes and the pollutants like SO2 and NO2 had been accumulated at a lower level. Proceeding the fog event, with the increase of SO2 and NO2 concentrations, condensability increased sharply. On the contrary, during the fog process, with increasing condensability, SO2 and NO2 concentrations decreased. This indicated that, acting as condensation nucleus, these accumulated pollutants were playing a key role in catalyzing the fog condensation. (ii) By analyzing mean gradient-, pulsation- and turbulence-distribution patterns derived from the wind measurements taken by the aforementioned tower-based instruments, they all indicated that about 10 hours before the fog onset, a signal foretelling potential strong disturbances in the lower boundary layer was detected, and a significant rise of both mean and disturbance kinetic energies was observed, revealing that the low-level wind shear was strengthened before the fog onset, consequentl

关键词： beijing heavy fog, SO2 and NO2, catalyzing fog condensation, disturbance kinetic energy signal.

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A Two-Moment Bulk Microphysics Coupled with a Mesoscale Model WRF:Model Description and First Results

A Two-Moment Bulk Microphysics Coupled with a Mesoscale Mode...

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强化科技基础推进气象现代化——第29届中国气象学会年会

作者： Gao Wenhua 1,Zhao Fengsheng 1,Hu Zhijin 2,and Feng Xuan 1 1 National Satellite meteorological Center,china meteorological administration,beijing 100081 2 chinese academy of meteorological sciences,china meteorological administration,beijing 100081

The chinese academy of meteorological sciences(CAMS) two-moment bulk microphysics scheme was adopted in this study to investigate the representation of cloud and precipitation processes under different environmental *** scheme predicts the mixing ratio of water vapor as well as the mixing ratios and number concentrations of cloud droplets,rain,ice,snow,and graupel.A new parameterization approach to simulate heterogeneous droplet activation was developed in this ***,the improved CAMS scheme was coupled with the Weather Research and Forecasting model(WRF v3.1),which made it possible to simulate the microphysics of clouds and precipitation as well as the cloud-aerosol interactions in selected atmospheric *** rain event occurring on 27-28 December 2008 in eastern china was simulated using the CAMS scheme and three sophisticated microphysics schemes in the WRF *** showed that the simulated 36-h accumulated precipitations were generally agreed with observations,and the CAMS scheme performed well in the southern area of the nested *** radar reflectivity,the averaged precipitation intensity,and the hydrometeor mixing ratios simulated by the CAMS scheme were generally consistent with those from other microphysics *** hydrometeor number concentrations simulated by the CAMS scheme were also close to the experiential values in stratus *** model results suggest that the CAMS scheme performs reasonably well in describing the microphysics of clouds and precipitation in the mesoscale WRF model.

关键词： droplet activation two-moment bulk microphysics WRF coupling

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