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Debating about the climate warming

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Progress in Natural Science:Materials International 2006年第1期16卷 1-6页

作者： WANG Shaowu1, LUO Yong2, ZHAO Zongci2, DONG Wenje2 and YANG Bao3 (1.Department of Atmospheric Sciences, School of Physics, Peking University, beijing 100871, china 2. Laboratory for climate Studies, china meteorological administration, beijing 100081, china 3. Institute of Cold and Arid Regions Environmental and Engineering, Chinese Academy of Sciences, Lanzhou 730000, china) Department of Atmospheric Sciences School of Physics Peking University Beijing 100871 China Laboratory for climate Studies China Meteorological Administration Beijing 100081 China Institute of Cold and Arid Regions Environmental and Engineering Chinese Academy of Sciences Lanzhou 730000 China

Debating about the climate warming is reviewed. Discussions have focused on the validity of the temperature reconstruction for the last millennium made by Mann et al. Arguments against and for the reconstruction are introduced. Temperature reconstructions by other authors are examined, including the one carried out by Wang et al. in 1996. It is concluded that: (1) Ability of reproducing temperature variability of time scale less than 10 a is limited, so no sufficient evidence proves that the 1990s was the warmest decade, and 1998 was the warmest year over the last millennium. (2) All of the temperature reconstructions by different authors demonstrate the occurrence of the MWP (Medieval Warm Period) and LIA (Little Ice Age) in low frequency band of temperature variations, though the peak in the MWP and trough in LIA varies from one reconstruction to the others. Therefore, terms of MWP and LIA can be used in studies of climate change. (3) The warming from 1975 to 2000 was significant, but we do not know if it was the strongest for the last millennium, which needs to be proved by more evidence.

关键词： climate warming MWP LIA the 20th century.

Numerical simulation of topography effects on the “00.7” severe rainfall in beijing

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Progress in Natural Science:Materials International 2005年第9期15卷 818-826页

作者： ZHANG Chaolin1**, JI Chongping1, KUO Yinghwa2, FAN Shuiyong1, XUAN Chunyi3 and CHEN Min1(1. Institute of Urban Meteorology, china meteorological administration, beijing 100089, china 2. Mesoscale and Microscale Meteorology Division, national center for Atmospheric Research, Boulder, CO 80307-3000, USA 3. beijing meteorological Bureau, beijing 100089, china) Institute of Urban Meteorology China Meteorological Administration Beijing 100089 China Mesoscale and Microscale Meteorology Division National Center for Atmospheric Research Boulder CO 80307-3000 United States beijing meteorological Bureau Beijing 100089 China

In an effort to study the severe rainfall event of 4—5th July 2000 in beijing (with 24h accumulated precipitation of 240 mm), we perform numerical simulations to investigate this event using the MM5v3.6 model. The model is initialized with the MM5/WRF 3DVAR analysis, which incorporates the ground-based GPS precipitable water vapor, automatic and conventional meteorological observations in its assimilation step. For 24 h accumulated precipitation forecast, the threat scores are 0.72, 0.76, 0.67 and 0.63, for thresholds of 1, 5, 10, and 20 mm, respectively. Holding other factors unchanged, sensitivity experiments were conducted with different topographic resolutions of 110, 50 and 3.7 km to investigate the topographic effects on precipitation over the beijing area. In these sensitivity experiments, we attempt to preserve the realistic orographic distribution in the model topography under the condition of keeping the dynamic-thermodynamic consistency of the initial model atmosphere to the extent possible. Results indicate that the unique topographic distribution and variations in the beijing area play an important role in determining the location, distribution and intensity of heavy precipitation.

关键词： topography heavy rainfall 3DVAR ground-based GPS numerical simulation.

Strategy and methodology of dynamical analogue prediction

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Science china Earth Sciences 2007年第10期50卷 1589-1599页

作者： REN HongLi1,2? & CHOU JiFan1 1 College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, china 2 Laboratory for climate Studies, national climate center, china meteorological administration, beijing 100081, china College of Atmospheric Sciences Lanzhou University Lanzhou 730000 China Laboratory for climate Studies National Climate Center China Meteorological Administration Beijing 100081 China College of Atmospheric Sciences Lanzhou University Lanzhou 730000 China

In order to effectively improve numerical prediction level by using current models and data, the strategy and methodology of dynamical analogue prediction (DAP) is deeply studied in the present paper. A new idea to predict the prediction errors of dynamical model on the basis of historical analogue information is put forward so as to transform the dynamical prediction problem into the estimation problem of prediction errors. In terms of such an idea, a new prediction method of final analogue correction of errors (FACE) is developed. Furthermore, the FACE is applied to extra-seasonal prediction experiments on an operational atmosphere-ocean coupled general circulation model. Prediction results of summer mean circulation and total precipitation show that the FACE can to some extent reduce prediction errors, recover prediction variances, and improve prediction skills. Besides, sensitive experiments also show that predictions based on the FACE are evidently influenced by the number of analogues, analogue-selected variables and analogy metric.

关键词： dynamical analogue prediction, prediction strategy, analogue correction of errors, extra-seasonal prediction

Prediction of solar cycle based on the invariant

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Chinese Science Bulletin 2003年第23期48卷 2568-2571页

作者： LIU Shijun, YU Xiaoding & CHEN Yongyi Chinese meteorological administration Training Centre, beijing 100081, china Correspondence should be addressed to Liu Shijun (e-mail: liushj@ ***) Chinese meteorological administration Training Centre Beijing China

A new method of predicting solar activities has been introduced in this paper. The method can predict both the occurrence time and the maximum number of sunspot at the same time. By studying the variation of sunspot, we find that the combination of the several variables was nearly in-variable during the entire solar cycles, as called invariant. And just only by determining the start time of a cycle, we can predict the occurrence time of cycles peak value accurately. Furthermore, according to observational data of the sunspot cycles, it showed that the sunspot maximum number has correlation not only with the prophase variety of the number in the cycle but also with the anaphase of the previous period. So we can introduce an equivalent regression coefficient, which can dynamically self-adapt to different cycle lengths, and effectively solve the inconsistency between the accuracy and the lead-time of the forecast. It can guarantee the satis-fied accuracy and effectively increases the lead-time of the forecast. This method can predict the maximum sunspot number for solar cycle at the approximate half rise of the period. This method predicts that the occurrence time of the maximum sunspot number for cycle 24 will be in January 2011.

关键词：太阳黑子太阳活动周期周期预测地磁指数

meteorological observations on Mount Everest in 2005

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Progress in Natural Science:Materials International 2007年第7期17卷 828-837页

作者： Xie Aihong~(1**) Qin Dahe~1 Ren Jiawen~1 Qin Xiang~1 Xiao Cunde~(1,2) Hou Shugui~1 Kang Shichang~(1,3) Yang Xingguo~(1,4) Jiang Youyan~1 (1.Key Laboratory of Cryosphere and Environment,Cold and Arid Regions Environment and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou 730000,china 2.Chinese Academy of meteorological Science,beijing 100081,china 3.Institute of Tibetan Plateau Research,Chinese Academy of Sciences,beijing 100085,china 4.Gansu Provincial meteorological Bureau,Lanzhou 730000,china) Key Laboratory of Cryosphere and Environment Cold and Arid Regions Environment and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Chinese Academy of meteorological Science Beijing 100081 China Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China Gansu Provincial meteorological Bureau Lanzhou 730000 China

Mount Everest,the highest point on the Earth is often referred to as the earth's third pole as such the place is relatively inaccessible and little is known about its *** April 2005,an automatic weather station was installed at the mountain's North Col(6523 m a.s.l.).According to the observational 10-minute mean and daily records,the meteorological characteristics were analyzed. All the meteorological elements displayed obvious diurnal variations during May 1 to July 22,*** monthly variation of daily meteo- rological elements on Mount Everest coincided with that on Dingri,the closest routine meteorological station,with the high correlation co- efficients of 0.928,0.877,0.682,0.755,0.826 and 0.676(n=83,pmeteorological *** conclusions are much important for research on meteorology and climate changes in the region.

关键词： Mount Everest meteorological observation Dingri County radiation air temperature relative humidity air pressure wind

Research on the dry intrusion accompanying the low vortex precipitation

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Science china Earth Sciences 2007年第9期50卷 1396-1408页

作者： YAO XiuPing1,2,3, WU GuoXiong1, ZHAO BingKe4, YU YuBin3 & YANG GuiMing2,5 1 LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100029, china 2 Institute of Heavy Rain, china meteorological administration, Wuhan 430074, china 3 china meteorological administration Training center, beijing 100081, china 4 Shanghai Typhoon Institute of china meteorological administration, Shanghai 200030, china 5 national meteorological center of the china meteorological administration, beijing 100081, china LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Institute of Heavy Rain China Meteorological Administration Wuhan 430074 China china meteorological administration Training center Beijing 100081 China LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Shanghai Typhoon Institute of china meteorological administration Shanghai 200030 China china meteorological administration Training center Beijing 100081 China Institute of Heavy Rain China Meteorological Administration Wuhan 430074 China national meteorological center of the china meteorological administration Beijing 100081 China

By employing the 6.7μm satellite vapor cloud images and NCEP/NCAR 1°×1° reanalysis datasets, the characteristics and mechanism of the dry intrusion, as well as its impacts on the low vortex precipita- tion at the Meiyu front are explored in this paper. It is found that the formation,development and main- tenance of the low vortex precipitation at the Meiyu front are closely related to the evolution of the dry intrusion. The dry intrusion is characterized by high potential vorticity (PV), low humidity and cold air. The dry intrusion exhibits as an obvious dark zone on vapor cloud images, an area in which atmos- pheric relative humidity is lower than 60%. However, the features of the dry intrusion on the vapor im- ages are clearer than that of the humidity field, for the former is the digital vapor cloud images with high temporal and spatial resolution, and it can be used to explore the finer characteristics of the develop- ment, evolution and supplement of the intrusion during the development of the low vortex. The dry intrusion impacts accompanying the low vortex precipitation at the Meiyu front come from all levels of the troposphere, with the strongest intrusion located at the upper troposphere. The dry and cold air intrudes the vicinity of the low vortex from the upper isentropic surface to the lower one, slanting eastward from lower to higher level. The low vortex precipitation region is usually situated in front of the dry intrusion where the relative humidity gradient is higher. The research also reveals that the mechanism of the dry intrusion is that the high potential vorticity descends from the upper troposphere to the lower level, therefore, the dry intrusion can be used as an important index of the high PV forcing. To the west of the low vortex precipitation, the upper level northerlies descend across the isentropic surface, then the dry cold advection can trigger the instable development in the mid-low troposphere. The dry intrusion enhances the low vort

关键词： Meiyu front, low vortex precipitation, dry intrusion, mechanisim, vapor image, potential vorticity, relative humidity

Evolution of terraces Ⅰ–Ⅲ along the Anning River, western Sichuan, based on pollen records and terrace structure

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Science china Earth Sciences 2011年第1期54卷 127-135页

作者： CHENG JianWu1,2 1 Institute of Geology, china Earthquake administration, beijing 100039, china 2 Earthquake administration of Gansu Province, Lanzhou 730000, china Institute of Geology China Earthquake Administration Beijing China Earthquake administration of Gansu Province Lanzhou China

This study reconstructs the long-term evolution of river terraces over large spatial scales along the Anning River, western Sichuan, and identifies external factors controlling terrace formation. Pollen record analysis and terrace structure indicate that formation of the middle section of terraces I-III resulted from the interaction of changing climates and uplift of the margins of the Qinghai-Tibet Plateau. The relative influence of climate and uplift in terrace formation changes in different periods. The terraces reveal multiple, gradual uplift events on the eastern Qinghai-Tibet Plateau, which is of great significance for determining uplift mechanisms across the entire plateau.

关键词： Anning River in western Sichuan terrace formation pollen paleoclimate

Forecasting the summer rainfall in North china using the year-to-year increment approach

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Science china Earth Sciences 2009年第4期52卷 532-539页

作者： FAN Ke1, LIN MeiJing1,2 & GAO YuZhong3 1 Nansen-Zhu International Research center, Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100029, china 2 Graduate University of the Chinese Academy of Sciences, beijing 100049, china 3 Heilongjiang meteorological administration, Harbin 150030, china Nansen-Zhu International Research center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of the Chinese Academy of Sciences Beijing China Heilongjiang meteorological administration Harbin China

A new approach to forecasting the year-to-year increment of rainfall in North china in July-August (JA) is proposed. DY is defined as the difference of a variable between the current year and the preceding year (year-to-year increment). NR denotes the seasonal mean precipitation rate over North china in JA. After analyzing the atmospheric circulation anomalies associated with the DY of NR, five key predictors for the DY of NR have been identified. The prediction model for the DY of NR is established by using multi-linear regression method and the NR is obtained (the current forecasted DY of NR added to the preceding observed NR). The prediction model shows a high correlation coefficient (0.8) between the simulated and the observed DY of NR throughout period 1965-1999, with an average relative root mean square error of 19% for the percentage of precipitation rate anomaly over North china. The prediction model makes a hindcast for 2000-2007, with an average relative root mean square error of 21% for the percentage of precipitation rate anomaly over North china. The model reproduces the downward trend of the percentage of precipitation rate anomaly over North china during 1965-2006. Because the current operational prediction models of the summer precipitation have average forecast scores of 60%-70%, it has been more difficult to forecast the summer rainfall over North china. Thus this new approach for predicting the year-to-year increment of the summer precipitation (and hence the summer precipitation itself) has the potential to significantly improve operational forecasting skill for summer precipitation.

关键词： annual increment North china precipitation prediction prediction skill

Study of statistically correcting model CMAQ-MOS for forecasting regional air quality

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Science china Earth Sciences 2005年第S2期48卷 155-172页

作者： XU Jianming, XU Xiangde, LIU Yu, DING Guoan, CHEN Huailiang, HU Jiangkai, ZHANG Jianchun, WU Hao, LI Weiliang, HE Jinhai, YANG Yuanqin & WANG Jiahe Nanjing University of Information Science & Technology, Nanjing 210044, china State Key Laboratory of Severe Weather, Chinese Academy of meteorological Sciences, beijing 100081, china meteorological Bureau of Henan Province, Institute of meteorological Sciences, Zhengzhou 450000, china national meteorological Centre of china meteorological administration, beijing 100081, china national meteorological Information Centre of china meteorological administration, beijing 100081, china Nanjing University of Information Science & Technology Nanjing 210044 China State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China meteorological Bureau of Henan Province Institute of Meteorological Sciences Zhengzhou 450000 China national meteorological Centre of china meteorological administration Beijing 100081 China national meteorological Information Centre of china meteorological administration Beijing 100081 China

Based on analysis of the air pollution observational data at 8 observation sites in beijing including outer suburbs during the period from September 2004 to March 2005, this paper reveals synchronal and in-phase characteristics in the spatial and temporal variation of air pollutants on a city-proper scale at deferent sites; describes seasonal differences of the pollutant emission influence between the heating and non-heating periods, also significantly local differences of the pollutant emission influence between the urban district and outer suburbs, i.e. the spatial and temporal distribution of air pollutant is closely related with that of the pollutant emission intensity. This study shows that due to complexity of the spatial and temporal distribution of pollution emission sources, the new generation Community Multi-scale Air Quality (CMAQ) model developed by the EPA of USA produced forecasts, as other models did, with a systematic error of significantly lower than observations, albeit the model has better capability than previous models had in predicting the spatial distribution and variation tendency of multi-sort pollutants. The reason might be that the CMAQ adopts average amount of pollutant emission inventory, so that the model is difficult to objectively and finely describe the distribution and variation of pollution emission sources intensity on different spatial and temporal scales in the areas, in which the pollution is to be forecast. In order to correct the systematic prediction error resulting from the average pollutant emission inventory in CMAQ, this study proposes a new way of combining dynamics and statistics and establishes a statistically correcting model CMAQ-MOS for forecasts of regional air quality by utilizing the relationship of CMAQ outputs with corresponding observations, and tests the forecast capability. The investigation of experiments presents that CMAQ-MOS reduces the systematic errors of CMAQ because of the uncertainty of pollution e

关键词： CMAQ-MOS point-area combination emission source influence emission inventory air quality.