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Dense fog events in the Yangtze Delta and their climatic characteristics

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Progress in Natural Science:Materials International 2007年第7期17卷 821-827页

作者： Zhou Zijiang~(**) Zhu Yanjun Ju Xiaohui (national meteorological{2. centre,Beijing 100081,china) [a]national meteorological{2. centre Beijing China

Based on daily observation records of fog and atmospheric visibility from 2. meteorological stations in the Yangtze Delta in the period from 1954 to 2.05,the identification standard of dense fog events(DFE)has been proposed in this paper,a quite complete time series of DFEs for the delta constructed,and the climate characteristics of these events analyzed *** results showed that there were 564 typical DFEs in the delta from 1954 to *** most frequent season for DFEs was from October to next April,when the number of the events accounted for 89.9% of the annual total,while the least frequent season was summer,when the number only accounted for 1.6% of the total due to higher temperature and more convective weather in the *** the Yangtze Delta, DFEs occurred less and were weaker in the 1960s,but turned to increase from the end of the 1970s to the beginning of the 1980s,with an abrupt change in ***,DFEs occurred more frequently,intensively,and indeterministically,and in particular,most fre- quently in the 1980s and intensively in the *** both the frequency and intensity of DFEs decline apparently in the period of 2.00—2.05 in the delta.

关键词： the Yangtze Delta dense fog events(DFE) inter-annual variation Mann-Kendall method running-t test

Arabian Peninsula-North Pacific Oscillation and its association with the Asian summer monsoon

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Science china Earth Sciences 2008年第7期51卷 1001-1012页

作者： SUN JianQi1, YUAN Wei2.& GAO YuZhong3 1 Nansen-Zhu International Research centre, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 10002.,{2. 2.2. meteorological administration Training centre, Beijing 100081,{2. 3 Heilongjiang meteorological Observatory, Harbin 150030,{2. 1. Nansen-Zhu International Research centre Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. china meteorological{2. Training centre Beijing 100081 China 3. Heilongjiang meteorological Observatory Harbin 150030 China

Using correlation and EOF analyses on sea level pressure from 57-year NCEP-NCAR reanalysis data, the Arabian Peninsula-North Pacific Oscillation (APNPO) is identified. The APNPO reflects the co-variability between the North Pacific high and South Asian summer monsoon low. This teleconnec- tion pattern is closely related to the Asian summer monsoon. On interannual timescale, it co-varies with both the East Asian summer monsoon (EASM) and South Asian summer monsoon (SASM); on decadal timescale, it co-varies with the EASM: both exhibit two abrupt climate changes in the middle 1960s and the late 1970s respectively. The possible physical process for the connections between the APNPO and Asian summer monsoon is then explored by analyzing the APNPO-related atmospheric circulations. The results show that with a strong APNPO, the Somali Jet, SASM flow, EASM flow, and South Asian high are all enhanced, and an anomalous anticyclone is produced at the upper level over northeast china via a zonal wave train. Meanwhile, the moisture transportation to the Asian monsoon regions is also strengthened in a strong APNPO year, leading to a strong moisture convergence over India and northern china. All these changes of circulations and moisture conditions finally result in an anoma- lous Asian summer monsoon and monsoon rainfall over India and northern china. In addition, the APNPO has a good persistence from spring to summer. The spring APNPO is also significantly corre- lated with Asian summer monsoon variability. The spring APNPO might therefore provide valuable in- formation for the prediction of Asian summer monsoon.

关键词： Arabian Peninsula-North Pacific Oscillation East Asian summer monsoon South Asian summer monsoon wave train abrupt climate change

Possible mechanism of the effect of convection over Asian-Australian “land bridge” on the East Asian summer monsoon onset

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Science china Earth Sciences 2006年第11期49卷 1223-1232页

作者： HE Jinhai1, WEN Min2. DING Yihui3 & ZHANG Renhe2.1. Jiangsu Key Laboratory of meteorological Disaster (KLME), Nanjing Institute of Meteorology, Nanjing University of Informa- tion Science and Technology, Nanjing 2.0044, china 2. State Key Laboratory of Severe Weather (LaSW), Chinese Academy of meteorological Sciences, Beijing 100081, china 3. national Climate Center, Chinese meteorological administration, Beijing 100081, china 1. Jiangsu Key Laboratory of meteorological Disaster (KLME) Nanjing Institute of Meteorology Nanjing University of Information Science and Technology Nanjing 210044 China 2. State Key Laboratory of Severe Weather (LaSW) Chinese Academy of Meteorological Sciences Beijing 100081 China 3. national Climate Center Chinese Meteorological Administration Beijing 100081 China

The Asian-Australian “land bridge” is an area with the most vigorous convection in Asian monsoon region in boreal spring, where the onset and march of convection are well associated with the onset of East Asian summer monsoon. The convection occurs over Indo-china Peninsula as early as mid-April, which exerts critical impact on the evolution of monsoon circulation. Before mid-April there are primarily sensible heatings to the atmosphere over Indo-china Peninsula and Indian Peninsula, so the apparent heating ratios over them decrease with height. However, after mid-April it changes into latent heating over Indo-china Peninsula due to the onset of convection, and the apparent heating ratio increases with height in mid- and lower troposphere. The vertical distribution of heating ratio and its differences between Indo-china Peninsula and Indian Peninsula are the key factors leading to the splitting of boreal subtropical high belt over the Bay of Bengal. Such mechanism is strongly supported by the fact that the evolution of the vertical heating ratio gradient above Indo-china Peninsula leads that of 850 hPa vorticity over the Bay of Bengal. Convections over Indo-china Peninsula and its surrounding areas further increase after the splitting. Since then, there is a positive feedback lying among the convective heating, the eastward retreat of the subtropical high and the march of monsoon, which is a possible mechanism of the advance of summer monsoon and convection from Indo-china Peninsula to South china Sea.

关键词： Asian-Australian 'land bridge', tropical convection, Indo-china Peninsula, the splitting of boreal subtropical high belt, East Asian summer monsoon onset.

Detection of nighttime sea fog/stratus over the Huang-hai Sea using MTSAT-1R IR data

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Acta Oceanologica Sinica 2009年第2期28卷 23-35页

作者： GAO Shanhong WU Wei ZHU Leilei FU Gang HUANG Bin Physical Oceanography Laboratory Ocean University of China Qingdao 266003 China Shandong Provincial meteorological Institute Jinan 250031 China national meteorological Center China Meteorological Administration Beijing 100081 China

A dual channel difference （DCD） method is applied to detect nighttime sea fog/stratus over the Huanghai Sea using the infrared （IR） data of shortwave （3.5-4.0 μm） and longwave （10.3-11.3 μm） channels from the Multi-functional Transport Satellite （MTSAT）-IR, i.e., shortwave minus longwave brightness temperature difference （SLTD）. Twenty-four sea fog events over the Huanghai Sea during March to July of 2.06 and 2.07 are chosen to determine a suitable value of SLTD for nighttime sea fog/stratus detection, and it is found that the value of-5.5-2.5℃ can be taken as a criterion. Two case examples of sea fog events are especially demonstrated in detail utilizing the criterion, and the results show that the derived sea fog/stratus coverage is quite reasonable. This coverage information is very helpful to analyze the formation and evolution of sea fog/stratus during night and can provide sea fog researchers with observational evidences for model results verification. However, more efforts are needed to further obtain vertical extent information of sea fog/stratus and attempt to discriminate between sea fog and stratus.

关键词： Huanghai Sea nighttime sea fog MTSAT-1R dual channel difference method

The onset and advance of the Asian summer monsoon

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Science Bulletin 2006年第1期51卷 80-88页

作者： Lü Junmei1,2.4, ZHANG Qingyun1, TAO Shiyan1 & JU Jianhua3 1. State Key Laboratory of Numerical Modeling for Atmospheric Sci- ences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 10002., china 2. Department of Atmospheric Sciences, Yunnan University, Kunming 650091, china 3. china meteorological administration Training centre, Beijing 100081, china 4. Graduate School of Chinese Academy of Sciences, Beijing 100039, china State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Department of Atmospheric Sciences Yunnan University Kunming 650091 China Graduate School of Chinese Academy of Sciences Beijing 100039 China china meteorological{2. Training centre Beijing 100081 China

Based on the daily outgoing longwave radiation (OLR) data from national Oceanic and At- mospheric administration (NOAA) satellites, the Cli- mate Prediction Center’s merged analysis of pre- cipitation (CMAP) data and the national Centers for Environmental Prediction/national Center for At- mospheric Research (NCEP/NCAR) reanalysis dataset, the mean intraseasonal variability of the Asian summer monsoon (ASM) is investigated by using power spectrum analysis, band-pass filter, and diagnostic analyses. The processes of the onset and advance of monsoon over the southern part of Indo- china Peninsula, the east coast of Bay of Bengal, the South china Sea and the Indian subcontinent are explored. It is found that there is an abrupt change in OLR, precipitation and zonal wind during the onset and advance of the ASM. It is also indicated that the southern part of Indochina Peninsula and the adja- cent Andaman Sea is the region where the earliest onset of the ASM occurs in the 2.d pentad of May.

关键词： Asian summer monsoon intraseasonal variability onset advance.

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 2.0044, china State Key Laboratory of Severe Weather, Chinese Academy of{2. Sciences, Beijing 100081, china meteorological Bureau of Henan Province, Institute of{2. Sciences, Zhengzhou 450000, china national{2. centre of china{2. {12., 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{2. 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 2.04 to March 2.05, 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.

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{2.,Shanghai 2.0030,china 2.tate Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG),Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 10002.,china 1. Shanghai Typhoon Institute of china meteorological{2. Shanghai 200030 China 2. State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 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

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{2., Beijing 100081, china Correspondence should be addressed to Liu Shijun (e-mail: liushj@ ***) Chinese meteorological administration Training{2.

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 2. will be in January 2.11.

关键词：太阳黑子太阳活动周期周期预测地磁指数

The characteristics of atmospheric CO_2.concentration variation of four national background stations in china

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Science china Earth Sciences 2009年第11期52卷 1857-1863页

作者： LIU LiXin, ZHOU LingXi, ZHANG XiaoChun, WEN Min, ZHANG Fang, YAO Bo & FANG ShuangXi Key Laboratory for Atmospheric Chemistry, centre for Atmosphere Watch and Services (CAWAS), Chinese Academy of Meteoro- logical Sciences (CAMS), china{2. administration (CMA), Beijing 100081, china Key Laboratory for Atmospheric Chemistry Centre for Atmosphere Watch and Services (CAWAS) Chinese Academy of Meteorological Sciences (CAMS) China Meteorological Administration (CMA) Beijing 100081 China

Atmospheric carbon dioxide is an important kind of greenhouse gas which influences global temperature. Its concentration variation could indicate the distribution of human and natural activities in various regions. Through the non-dispersive infrared method, flask sampling of atmospheric CO2.concen- tration was measured weekly at four national background stations including Waliguan, Shangdianzi, Lin’an, and Longfengshan. Based on the data collected from September 2.06 to August 2.07, along with the Waliguan station’s experience on in situ observational data processing, the selection methods for sampling data through the atmospheric background CO2.concentration analysis were preliminarily discussed. On the basis of this result, the variation features of the four typical regions’ atmospheric background CO2.concentration was analyzed for the first time. The results show that the atmospheric CO2.concentration at Waliguan, Shangdianzi, Lin’an, and Longfengshan is 383.5, 385.9, 387.8, and 384.3 ppm, respectively. During the research period, CO2.concentration at the Waliguan station changed slightly. However, the CO2.concentration changed sharply at the Shangdianzi and the Lin’an stations due to the great influence of human activities in the Jingjinji and the Changjiang Delta economic zones, and changed regularly with seasons at Longfengshan station under dual influences of human activities and plant photosynthesis. The results from this study can lay the foundation for more profound studies on atmospheric CO2.concentration level of different areas in china, and could be used to improve the understanding of carbon source and sink distribution.

关键词： atmospheric CO2 flask sampling background data selection CO2 concentration regional difference