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Persistent anomalous flows over the subtropical western Pacific insummer

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Chinese Science Bulletin 1998年第8期43卷 672-675页

作者： ZHUANG Shiyu\+1 and JI Liren\+2 1. national meteorological Centre, china meteorological administration, beijing 100081, china 2. LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100080, china national meteorological Ccntre China Meteomlcgical Administration Beijing China LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The distribution of global persistent anomalies shows that the subtropical western Pacific is a key region with high_frequency occurrence of persistent anomalies. Analyses of streamfunction anomalies, OLR anomalies etc. suggest that the convective heating related to Indian monsoon might be responsible for the development of WPA. The results of numerical experiment by two linear barotropic models support the observation.

关键词： persistent anomalies subtropical high Indian monsoon anomalous forcing.

Principle and application of three-band gradient difference vegetation index

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Science china Earth Sciences 2005年第2期48卷 241-249页

作者： TANG Shihao, ZHU Qijiang, WANG Jindi, ZHOU Yuyu & ZHAO Feng Research center for Remote Sensing and GIS, Department of Geography, beijing Normal University, beijing 100875, china national Satellite meteorological center, china meteorological administration, beijing 100081, china Research center for Remote Sensing and GIS Department of Geography Beijing Normal University Beijing China national Satellite meteorological center China Meteorological Administration Beijing China

Vegetation index is a simple, effective and experiential measurement of terrestrial vegetation activity, and plays a very important role in qualitative and quantitative remote sensing. Aiming at shortages of current vegetation indices, and starting from the analysis of vegetation spectral characteristics, we put forward a new vegetation index, the three-band gradient difference vegetation index (TGDVI), and established algorithms to inverse crown cover fraction and leaf area index (LAI) from it. Theoretical analysis and model simulation show that TGDVI has high saturation point and the ability to remove the influence of background to some degree, and the explicit functional relation with crown cover fraction and LAI can be established. Moreover, study shows that TGDVI also has the ability to partly remove the influence of thin cloud. Experiment in the Shunyi District, beijing, china shows that reasonable result can be reached using the vegetation index to retrieve LAI. We also theoretically analyzed the reason why the normalized difference vegetation index (NDVI) owns the low saturation point, and show that it is determined by the definition of NDVI and the characteristic of vegetation spectra, and is unavoidable to some degree. Meanwhile, through model simulation, we also indicate that the relationship between simple ratio vegetation index (SR) and LAI closes to a piecewise linear one instead of a linear one, which is mainly caused by the influence of background and different change rates of reflectance in red and infrared bands with LAI increasing.

关键词： vegetation index, remote sensing, LAI, crown cover fraction, remote sensing inversion.

Progress in china’s climate change study in the 20th century

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Journal of Geographical Sciences 2004年第S1期 5-13页

作者： ZHAI Panmao1,2, CHAO Qingchen1,2, ZOU Xukai1,2(1. Laboratory for climate Studies, china meteorological administration, beijing 100081, china 2. national climate center, china meteorological administration, beijing 100081, china)

Studies on the 20th century climate change in china have revealed that under the background of global warming over the past century, climate in china has also experienced significant change with mean annual temperature increased by about 0.5 oC. More reliable results for the latter part of the 20th century indicate that the largest warming occurred in Northwest china, North china and Northeast china, and the warming in winter is most significant. Although no obvious increase or decrease trends were detected for mean precipitation over china in the past half century, regional differences are very distinct. In the middle and lower reaches of the Yangtze River, precipitation increased, while that in the Yellow River Basin markedly decreased. Studies suggest that climate change in china seems to be related not only with the internal factors such as ENSO, PDO, and the others, but also with the anthropogenic effects such as greenhouse gas emissions, and land use. The future climate change studies in china seem to be important in narrowing understanding the nature of china's climate change and its main causes, since it is significant for projection and for impact assessment of climate change in the future.

关键词： th century climate change china

Ocean color products retrieval and validation around china coast with MODIS

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Acta Oceanologica Sinica 2010年第4期29卷 21-27页

作者： SUN Lingt GUO Maohua WANG Xiaomei Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites China Meteorological Administration （LRCVES/CMA） National Satellite Meteorological Center China Meteorological Administration Beijing 100081 China national Satellite Ocean Application Service State Oceanic Administration Beijing 100081 China

Waters along china coast are very turbid with high concentrations of suspended sediment nearly all the time,especially at the Hangzhou Bay,the Changjiang （Yangtze） River Estuary and the shoal along Jiangsu *** these turbid and optically complex waters,the standard MODIS ocean color products tend to have invalid *** the water-leaving radiances in the near-infrared （NIR） are significant resulting from the strong scattering of suspended particles,the standard MODIS atmospheric correction algorithm often gets no results or produces significant *** because of the complex water optical properties,the OC3 model used in the standard MODIS data processing tends to get extremely high chlorophyll-a （Chl-a） *** this paper,we present an atmospheric correction approach using MODIS short wave infrared （SWIR） bands based on the fact that water-leaving radiances are negligible in the SWIR region because of the extreme strong absorption of water even in turbid waters.A regional Chl-a concentration estimation model is also constructed for MODIS from in situ *** algorithms are applied to MODIS Aqua data processing in the china coastal *** situ data collected in the Yellow Sea and the East china Sea in spring and autumn,2003 are used to validate the *** good results have been *** is noted that water-leaving reflectance in the NIR bands are significant in waters along the china coast with high sediment *** satellite derived and in-situ reflectance spectra can match in the turbid waters along china coast,and there is relatively good linear relationship between satellite derived and in-situ *** RMSE value of Rrs（λ） is 0.0031 sr ？1 for all the nine ocean color bands （412 to 869 nm）.The satellite-derived Chl-a value is in the reasonable range and the root mean square percentage difference is 46.1%.

关键词： ocean color atmospheric correction chlorophyll-a MODIS china coastal region validation

Multiple time scale evaluation of the energy balance during the maize growing season,and a new reason for energy imbalance

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Science china Earth Sciences 2009年第1期52卷 108-117页

作者： GUO JianXia1,2,BIAN LinGen3 & DAI YongJiu2 1 meteorological Observation center of china meteorological administration,beijing 100081,china 2 State Key Laboratory of Remote Sensing Science,School of Geography and Remote Sensing Science,beijing Normal University,beijing 100875,china 3 Chinese Academy of meteorological Sciences,beijing 100081,china meteorological Observation center of china meteorological administration Beijing China State Key Laboratory of Remote Sensing Science School of Geography and Remote Sensing Science Beijing Normal University Beijing China Chinese Academy of meteorological Sciences Beijing China

Energy imbalance is a common problem associated with the measurement of surface energy using the eddy covariance *** the evaluation of the energy balance,people usually pay more attention to the statistical result that the effective energy(the sum of sensible and latent heat) is systematically lower than the available energy(the difference of net radiation and ground heat flux).However,little attention has been paid to the existence of the reversed situation when the effective energy is larger than the available energy or their contribution to the overall energy closure *** this paper,based on the analysis of the energy balance on multiple time scales across the maize growth season,we conclude that the non-synchronization of energy components is the main reason for the existence of the reversed *** shifting the phase of the effective energy components half an hour ahead,the rates of energy closure over all time scales are improved and dramatically reduce the number of the half-hourly samples when the energy ratio exceeds 1 or is below *** to the characteristics of the energy distribution and transformation over multiple time scales,latent heat is always the main type of energy cost,and the residual of the energy balance increases with the growth of the maize plant surpassing the sensible heat for seventy *** is suggested that the heat storage and photosynthetic energy play an important role in the energy balance during the growing period of maize.

关键词： maize energy balance multiple time scale energy hysteresis

Sensitivity experiments and assessment of climatic changes in china induced by greenhouse effect

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Journal of Environmental Sciences 1990年第4期2卷 73-84页

作者： Zhao Zongci and Ding YihuiAcademy of meteorological Science,State meteorological administration,beijing 100081,china

Climatic changes can be separated into two parts: natural changes -and human activity influenced on climatic changes. The observed data could not only show the effects caused by human activity. Several simulated results as simulated by the GCMs induced by the greenhouse effects in china .have been analysed. It is shown that an obvious warming of about 3-6℃ in winter and 2-5℃ in summer in china as simulated by the GCMs induced by doubling CO2 have been found. There are getting drier or wetter regions in china due to doubled CO2 as simulated by most of models. Comparing the simulated results with the observed data in china, some simulated results are able to be believed. The GCMs should be improved, especially in the regional areas.

关键词： greenhouse effect climatic changes global warming.

A preliminary analysis of physical mechanism of transformation process from a landed typhoon into an extratropical cyclone

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Acta Oceanologica Sinica 1992年第4期11卷 525-535页

作者： Zhang Qiuqing and Ding Yihui 1. national Research center for Marine. Environment Forecasts, beijing 100081, china2. Academy of meteorological Science, State meteorological administration, beijing 100081, china national Research center for Marine Environment Forecasts Beijing 100081 China China

A diagnostic study is performed in the paper on the process of typhoon Norris (1980) transforming into an ex-tratropical cyclone after its landing over Southeast china. The main findings are as follows:The changes of kinetic energy are mainly attributed to the generation due to non-divergent wind. During the early stage of the typhoon landing, there exits only a small quantity of kinetic energy exchanging with the environment. And after it is transformed into an extratropical cyclone, a large amount of kinetic energy is exported from the system toward the *** horizontal and vertical flux-divergence terms of eddy available potenlial energy are the prominent sinks in the budgets of eddy kinetic energy. The generations of eddy kinetic energy due to both the barotropic and baroclinic processes are source terms. The former is remarkable during the initial stage. But after the depression is transformed into an extratropical cyclone, the roles of the generation by the barotropic and baroclinic processes are reversed, 1. e. , the latter has become more significant than the *** heating is the most dominant heat source. The terms of vertical heat flux by cumulus and large-scale motion are the major sinks. And the latter is prominent after the system is transformed into an extratropical cycfone.

关键词： A preliminary analysis of physical mechanism of transformation process from a landed typhoon into an extratropical cyclone

Monitoring of the 2011 spring low ozone events in the Arctic region

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Chinese Science Bulletin 2011年第27期56卷 2893-2896页

作者： LIU NianQing 1,2 , HUANG FuXiang 1,2 WANG WeiHe 1,2 1 national Satellite meteorological center, beijing 100081, china 2 Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites, china meteorological administration, beijing 100081, china national Satellite meteorological center Beijing China Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites China Meteorological Administration Beijing China

Data from FY-3B SBUS and NOAA SBUV/2 were used to monitor ozone levels in the Arctic region from March 1 to April 5, 2011. Results revealed a significant ozone depletion in the area, with total ozone levels between 200-250 DU. The ozone levels recorded were 100-200 DU below normal, and in some parts the levels were as low as 200 DU, indicating a mini ozone-hole. During the sampling period, the ozone depletion area underwent identifiable expansion and detraction, a rotation around the North Pole from the west to the east, and a longitudinal movement from the Pole, spreading to the mid latitudes. The effects of these rare low ozone events were not only felt in the Arctic, but also extended to densely populated areas between Europe and the middle of Russia. In this region, rapidly increasing levels of ultraviolet radiation were detected at the Earth's surface. Given the significant risk that this poses to both the environment and people's health, this occurrence has significant global implications.

关键词：北极地区臭氧水监测事件人口稠密地区中纬度地区 NOAA 调查结果

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

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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 210093, china 2 Key Laboratory 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 Academy 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