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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 2006 and 2007 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

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

Climate change tendency and grassland vegetation response during the growth season in Three-River Source Region

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Science china Earth Sciences 2010年第10期53卷 1506-1512页

作者： QIAN Shuan1,FU Yang2 & PAN FeiFei3 1 National meteorological Center,Beijing 100081,china 2 Qinghai meteorological Research institute,Xining 810001,china 3 Department of Geography,University of North Texas,Denton,TX 76203,USA National meteorological Center Beijing China Qinghai meteorological Research institute Xining China Department of Geography University of North Texas Denton USA

Climate change,climate suitablity change for grassland vegetation,and grassland response to climate change during the growth season are studied systematically by using meteorological data of temperature,precipitation,and length of sunlight from 1961 to 2007,NOAA/AVHRR NDVI from 1982 to 2006,and observations of grass height,biomass,and coverage in enclosed grassland from 1994 to *** models are developed to evaluate climate change and the climatic suitability of grassland vegetation *** temperature,accumulative precipitation,and length of sunlight during the growth season increased from 1961 to 2007 at rates of 0.24°C/10 yr,2.32 mm/10 yr,and 2.81 h/10 yr,*** increase rates of ave-rage temperature between April and May,and between June and August are 0.17 and 0.30°C/10 yr;accumulative rainfall between April and May increased at a rate of 2.80 mm/10 yr,and accumulative rainfall between June and August decreased at a rate of 0.38 mm/10 yr;the increase rates of accumulative length of sunlight between April and May,and between June and August are 2.15 and 1.2 h/10 *** climatic suitability of grassland vegetation growth showed an increasing trend,and the increase rate between April and May is greater than that between June and *** NDVI observations from 1982 to 2006 and measurements of grass height,dry biomass,and coverage from 1994 to 2006 show that the climate change has resulted in an increase in plant productivity of the grassland in Three-River Source *** some protection measures are taken as soon as possible,the deteriorated grassland in Three-River Source Region can recover.

关键词： climate change climate suitability change grassland vegetation Three-River Source Region

CO_2 background concentration in the atmosphere over the Chinese mainland

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Chinese Science Bulletin 2002年第14期47卷 1217-1220页

作者： WANG Gengchen, WEN Yupu, KONG Qinxin, REN Lixin & WANG Mulininstitute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, china Academy of meteorological Sciences, china meteorological administration, Beijing 100086, china institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Academy of meteorological Sciences China Meteorological Administration Beijing China

Based on the long-term monitoring data on CO2 concentration, variation trend and characteristics of CO2 background concentration in the atmosphere over the Chinese mainland are analyzed. Results show that the increasing trend of CO2 background concentration in the atmosphere over the Chinese mainland has appeared during the period of 1991-2000. The average annual CO2 growth increment is 1.59μL/L, and the average annual CO2 growth rate is 0.44%. Distinct seasonal variations of CO2 background concentration are observed, and the averaged amplitude of CO2 seasonal variations is 10.35μL/L. Regional variation characteristics of CO2 background concentration in the atmosphere and possible impact of human activities on these variations over the Chinese mainland are discussed as well.

关键词： CO2 background concentration Chinese mainland CO2 growth rate CO2 seasonal variation CO2 regional variation CO2 variation trend.

Some characteristics of the atmosphere during an adiabatic process

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Progress in Natural Science:Materials International 2006年第6期16卷 644-648页

作者： GAO Li, LI Jianping and REN Hongli (LASG, institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, china Graduate School of Chinese Academy of Sciences, Beijing 100049, china National Climate Center, Laboratory of Climate Studies, china meteorological administration, Beijing 100081, china) LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate School of Chinese Academy of Sciences Beijing 100049 China National Climate Center Laboratory of Climatic Studies China Meterological Administration Beijing 100081 China

Some important characteristics of the atmosphere during an adiabatic process are investigated, which include the invariability of atmospheric entropy range and local surface potential temperature, the conservation of the atmospheric mass intervened between any isentropic surface and the ground, and the isentropic surface intersecting with the ground. The analysis shows that the atmospheric reference state (ARS) for investigation on available potential energy (APE) should be defined objectively as the state which could be approached from the existing atmosphere by adiabatic adjustment, and be related to initial atmospheric state before adjustment. For the initial atmosphere state at any time, its corresponding ARS is different from the one at another time. Based on the above-mentioned conclusions, the reference state proposed by Lorenz cannot be obtained physically, so a new conception, the conditional minimum total potential energy, is put forward in order to objectively investigate atmospheric APE.

关键词： available potential energy adiabatic isentropic surface atmospheric reference state conditional minimum total potential energy.

The characteristics of sea fog with different airflow over the Huanghai Sea in boreal spring

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Acta Oceanologica Sinica 2010年第4期29卷 3-12页

作者： HUANG Jian WANG Xin ZHOU Wen HUANG Huijun WANG Dongxiao ZHOU Faxiu institute of Tropical and Marine meteorology China Meteorological Administration Guangzhou 510080 China Guy Carpenter Asia-Pacific Climate Impact Centre School of Energy and Environment City University of Hong Kong Hong Kong China CAS key laboratory of tropical marine environmental dynamics South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China Department of meteorology Ocean University of China Qingdao 262003 China

Using the observations from ICOADS datasets and contemporaneous NCEP/NCAR reanalysis datasets during 1960-2002,the study classifies the airflows in favor of sea fog over the Huanghai （Yellow） Sea in boreal spring （April-May） with the method of trajectory analysis,and analyzes the changes of proportions of warm and cold sea fogs along different paths of *** to the heat balance equation,we investigate the relationships between the marine meteorological conditions and the proportion of warm and cold sea fog along different airflow *** major results are summarized as follows.（1） Sea fogs over the Huanghai Sea in spring are not only warm fog but also cold *** proportion of warm fog only accounts for 44% in April,while increases as high as 57% in May.（2） Four primary airflow paths leading to spring sea fog are *** are originated from the northwest,east,southeast and southwest of the Huanghai Sea,*** occurrence ratios of the warm sea fog along the east and southeast airflow paths are high of 55% and 70%,while these along the southwest and northwest airflow paths are merely 17.9% and 50%.（3） The key physical processes governing the warm/cold sea fog are heat advection transport,longwave radiation cooling at fog top,solar shortwave warming and latent heat flux between airsea interfaces.（4） The characteristics of sea fog along the four airflow paths relate closely to the conditions of water vapor advection,and the vertical distribution of relative humidity.

关键词： spring sea fog over the Huanghai Sea airflow paths water vapor flux heat advection vertical distribution of water vapor

Three-dimensional decomposition method of global atmospheric circulation

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Science china Earth Sciences 2008年第3期51卷 386-402页

作者： LIU HaiTao1,2,3, HU ShuJuan4, XU Ming5 & CHOU JiFan6,7 1 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, china 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, china 3 Beijing Climate Center, Beijing 100089, china 4 Department of Mathematics, Lanzhou University, Lanzhou 730000, china 5 Shanghai Typhoon institute, Shanghai 200030, china 6 Department of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, china 7 china meteorological administration Training Center, Beijing 100089, china State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China Beijing Climate Center Beijing China Department of Mathematics Lanzhou University Lanzhou China Shanghai Typhoon institute Shanghai China Department of Atmospheric Sciences Lanzhou University Lanzhou China china meteorological administration Training Center Beijing China

By adopting the idea of three-dimensional Walker, Hadley and Rossby stream functions, the global atmospheric circulation can be considered as the sum of three stream functions from a global perspective. Therefore, a m... 详细信息

关键词： three-dimensional decomposition of the global atmospheric circulation generalized Walker Hadley and Rossby stream functions existence and uniqueness vertical motion

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 200030,china 2State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG),institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,china Shanghai Typhoon institute of china meteorological administration Shanghai China State Key Laboratory 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

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.