Decadal cimatic variations indicated by dulan tree-ring and comparison with other proxy data in China of the last 2000 years

Based on high-resolution tree-ring data from Dulan area of Qinghai Province, five spells have been divided: the warm period before 230’s A. D., the cold period between 240’s A. D. and 800’s A. D., the significantly warm period between 810’s A. D. and 1070’s, i. e. “Medieval Warm Period”, the cold period including the “Little Ice Age” 1420’ – 1870’s and the warming period since 1880’s. All the eleven coldest or warmest decades and several great abrupt changes took place before the Middle Ages, indicating that climatic system operated in great instability during the period 150’s – 1100’s A. D., Comparison of the tree-ring data with other temperature proxy data from East China, Guliya ice core as well as the south of Qinghai-Xizang Plateau shows that such great climatic events as Eastern Han warm period between the beginning of the 1st century and the previous fifty years of the third century, the cold period covering the span of the Wei, the Jin, and the Southern and Northern dynasties, the well-known “Medieval Warm Period” as well as the “Little Ice Age” appeared in these series such as East China and Dulan area. Only the first two climatic events were recorded conspicuously in Guliya ice core while the “Medieval Warm Period” and “Little Ice Age” is far weaker. Also, the well-defined “Medieval Warm Period” didn’t occurred in the south of Qinghai-Xizang Plateau. The warming since the 20th century is the warmest in the last 2000 years Guliya ice core, the second in Dulan area and East China, but it scarcely seems pronounced in the eastern part of Qinghai-Xizang Plateau. Foundation item: Under the auspices of the projects of the Chinese Academy of Sciences (KZ951-A1-204-02 and KZ951-A1 402-03). Biography: YANG Bao(1971–), male, a native of Yanggao County, Shanxi Province, Ph. D. His research interestinclude global change.     

Climatic variations in the coastal zone — Comparison between the Po River delta (Adriatic Sea,Italy) and the Huanghe River delta (Bohai Sea,China)

The aim of this work is to research the influence of natural climatic changes on the evolution of the coastal zone in modern times and the possible implication of human activities on the configuration of the present coastline. Comparison of data of two very far and different areas, the Po River delta, Adriatic Sea and the Huanghe River delta, Bohai Sea, reveals the planetary diffusion of climatic fluctuations and their effects on coastal evolution. Contribution No. 820 from the Marine Geology Institute, C. N. R., Italy. Contribution No.2207 from the Institute of Oceanology, Academia Sinica. Project supported by the National Natural Science Foundation of China.     

西南地区近21年来NDVI变化特征分析

利用美国国家航天航空局（NASA）归一化植被指数（GIMMS NDVI）资料,初步分析了近21年（1982~2002）来西南地区植被变化特征。结果发现：21年来西南地区植被覆盖状况较好,总体呈增加趋势,同时也存在较明显的季节和区域差异：春季西南大部分地区植被呈较明显的增加趋势。夏季全区NDVI以显著的减小趋势为主,尤以90年代中期以后更为明显。秋季NDVI与夏季类似同样表现为减少趋势,并且范围有所增加。冬季ND-VI以增加为主,存在明显的东西反向特征,东部以减少为主,西部则以增加为主。     

末次间冰期-末次冰期柴达木盆地东部气候演化形式

柴达木盆地第四系富含介形类化石，介形类生物组合可以反映古气候变化。以盆地东部达参1井中的两种主要介形类(Ilyocypris inermis和Cyprideis torasa)的丰度特征为气候指标，对末次间冰期和末次冰期的盆地气候演变形式进行了恢复。认为柴达木盆地东部末次间冰期和末次冰期的气候演化既有着和全球同步的特点，也有着本区域独自的特征。介形类丰度曲线表明：末次间冰期(MIS5)，以Cyprideis torasa为主，整体上为暖型气候，依据介形类特征，又可分为5e，5c．5a三个暖期和5d．5b两个冷期，暖期到冷期都以介形类丰度的大幅突降为特征；末次冰期(MIS4-2)以Ilyocypris inermis为主，整体为冷型气候。其中，早冰阶(MIS4)两种介形类丰度都较低．而间冰阶(MIS3)介形类丰度明显增高，并可划分为3c．3a两个暖期和3b一个冷期。在间冰阶结束之后，介形类大量消失，llyocypris inermis完全灭绝，石盐大范围析出．盆地进入了末次冰期盛冰阶(MIS2)。     

Impacts of climatic change on river runoff in northern Xinjiang of China over last fifty years

The characteristics of climatic change and river runoff, as well as the response of river runoff to climatic change in the northern Xinjiang are analyzed on the basis of the hydrological and meteorological data over the last 50 years by the methods of Mann-Kendall nonparametric test and the nonlinear regression model. The results show that: 1) The temperature and the precipitation increased significantly in the whole northern Xinjiang, but the precipitation displayed no obvious change, or even a decreasing trend in the northern mountainous area of the northern Xinjiang. 2) River runoff varied in different regions in the northern Xinjiang. It significantly increased in the northern slope of the Tianshan Mountains and the north of the northern Xinjiang (p=0.05), while slightly increased in the west of the northern Xinjiang. 3) North Atlantic Oscillation (NAO) affects river runoff by influencing temperature and precipita-tion. The NAO and precipitation had apparent significant correlations with the river runoff, but the temperature did not in the northern Xinjiang. Since the mid-1990s river runoff increase was mainly caused by the increasing temperature in the northern slope of the Tianshan Mountains and the north of the northern Xinjiang. Increased precipitation resulted in increased river runoff in the west of the northern Xinjiang.     

Comparison between reconstructions of global anthropogenic land cover change over past two millennia

Three global datasets, the History Database of the Global Environment (HYDE), Kaplan and Krumhardt (KK) and Pongratz of reconstructed anthropogenic land cover change (ALCC) were introduced and compared in this paper. The HYDE dataset was reconstructed by Goldewijk and his colleagues at the National Institute of Public Health and the Environment in Netherland, covering the past 12 000 years. The KK dataset was reconstructed by Kaplan and his colleagues, the Soil-Vegetation-Atmosphere Research Group at the Institute of Environmental Engineering in Switzerland, covering the past 8000 years. The Pongratz dataset was reconstructed by Pon-gratz and her colleagues at the Max Planck Institute for Meteorology in Germany, covering AD 800-1992. The results show that the reconstructed datasets are quite different from each other due to the different methods used. The three datasets all allocated the historical ALCC according to human population density. The main reason causing the differences among the three datasets lies on the different relationships between population density and land use used in each reconstructed dataset. The KK dataset is better than the other two datasets for two important reasons. First, it used the nonlinear relationship between population density and land use, while the other two used the linear relationship. Second, Kaplan and his colleagues adopted the technological development and intensification parameters and considered the wood harvesting and the long-term fallow area resulted from shifting cultivation, which were neglected in the reconstructions of the other two datasets. Therefore, the KK dataset is more suitable as one of the anthropogenic forcing fields for climate simulation over the past two millennia that is recently concerned by two projects, the National Basic Research Program and the Strategic and Special Frontier Project of Science and Technology of the Chinese Academy of Sciences.     

Formation and evolution of the modem warm current system in the East China Sea and the Yellow Sea since the last deglaciation

To reconstruct the formation and evolution process of the warm current system within the East China Sea (ECS) and the Yellow Sea (YS) since the last deglaciation, the paleoceangraphic records in core DGKS9603, core CSH1 and core YSDPI02, which were retrieved from the mainstream of the Kuroshio Current (KC), the edge of the modem Tsushima Warm Current (TWC) and muddy region under cold waters accreted with the Yellow Sea Warm Current (YSWC) respectively, were synthetically analyzed. The results indicate that the formation and evolution of the modem warm current system in the ECS and the YS has been accompanied by the development of the KC and impulse rising of the sea level since the last deglaciation. The influence of the KC on the Okinawa Trough had enhanced since 16 cal kyr BE and synchronously the modem TWC began to develop with the rising of sea level and finally formed at about 8.5 cal kyr BP. The KC had experienced two weakening process during the Heinrich event 1 and the Younger Drays event from 16 to 8.5 cal kyr BP. The period of 7-6 cal kyr BP was the strongest stage of the KC and the TWC since the last deglaciation. The YSWC has appeared at about 6.4 cal kyr BP. Thus,the warm current system of the ECS and the YS has ultimately formed. The weakness of the KC,indicated by the occurrence of Pulleniatina minimum event (PME) during the period from 5.3 to 2.8 cal kyr BE caused the main stream of the TWC to shift eastward to the Pacific Ocean around about 3 cal kyr BP. The process resulted in the intruding of continent shelf cold water mass with rich nutrients. Synchronously, the strength of the YSWC was relatively weak and the related cold water body was active at the early-mid stage of its appearance against the PME background, which resulted in the quick formation of muddy deposit system in the southeastern YS. The strength of the warm current system in the ECS and the YS has enhanced evidently, and approached to the modern condition gradually since 3 cal kyr BP.     

Distribution of dissolved inorganic arsenic and its seasonal variations in the coastal area of the east China sea

Water samples were collected in the coastal area of the Changjiang Estuary on four cruises from August 2002 to May 2003. The seasonal variations of dissolved inorganic arsenic （DIAs） distributions were analyzed. The results showed that the distributions of DIAs were mainly influenced by Water （KSSW）. The concentration of the total dissolved the terrestrial input and the intrusion of the Kuroshio Subsurface inorganic arsenic （TDIAs） decreased consecutively from winter to summer, while it increased in autumn. The distributions of TDIAs showed some relationships with salinity and suspended particulate matter （SPM）. The relationships between DIAs speciation （including arsenite [ As（ Ⅲ ） ] and arsenate [ As（ Ⅴ ） ]）, biological activity and the availabilities of the phosphate were investigated in the study area for the cruise August 2002. The ratio of As （Ⅲ）/TDIAs increased with the decrease of phosphate concentrations. In the bottom water, the As（ Ⅲ ）/TDIAs ratio decreased with the increasing of N/P. The concentration of TDIAs decreased 28.7% approximately after the occurrence of harmful algal blooms （HAB） because of the uptake of arsenate by algae. Further study is needed about the arsenic source/sink relationships in their vertical or horizontal profiles and the uptake mechanism during the occurrence of harmful algal blooms.     

成都平原中西部近40年气候特征及其变化研究

利用成都平原中西部5个气象观测站的降水、温度和日照资料,分析了成都平原中西部降水、温度和日照的分布规律、气候特征及其变化,得出以上地区年平均气温存在准4年的振动周期;1990年以来大部分地区存在降水减少,气温升高,日照减少的现象.     

CLIMATIC TREND INDICATED BY VARIATIONS OF GLACIERS AND LAKES IN THE TIANSHAN MOUNTAINS

ＣＬＩＭＡＴＩＣＴＲＥＮＤＩＮＤＩＣＡＴＥＤＢＹＶＡＲＩＡＴＩＯＮＳＯＦＧＬＡＣＩＥＲＳＡＮＤＬＡＫＥＳＩＮＴＨＥＴＩＡＮＳＨＡＮＭＯＵＮＴＡＩＮＳ￥ＨｕＲｕｊｉ；ＹａｎｇＣｈｕａｎｄｅ；ＭａＨｏｎｇ；ＪｉａｎｇＦｅｎｇｑｉｎｇ（ＸｉｎｊｉａｎｇＩｎ...     

Interannual variations of surface winds over China marginal seas

In a study of surface monsoon winds over the China marginal seas, Sun et al. (2012) use singular value decomposition method to identify regional dominant modes and analyze their interdecadal variability. This paper continues to evaluate the interannual variability of each dominant mode and its relation to various atmospheric, oceanic and land factors. The findings include: 1) The intensity of the winter monsoon over the East China Sea is highly correlated with the Siberian High intensity and anti-correlated with the latitudinal position of the Aleutian Low as well as the rainfall in eastern China, Korean Peninsula and Japan; 2) The western Pacific subtropical high is significantly correlated with the summer monsoon intensity over the East China Sea and anti-correlated with the summer monsoon over the South China Sea; 3) The winter monsoon in a broad zonal belt through the Luzon Strait is dominated by the ENSO signal, strengthening in the La Ni a phase and weakening in the El Ni o phase. This inverse relation exhibits interdecadal shift with a period of weak correlation in the 1980s; 4) Analysis of tidal records validates the interdecadal weakening of the East Asian summer monsoon and reveals an atmospheric bridge that conveys the ENSO signal into the South China Sea via the winter monsoon.     

GEOGRAPHIC ENVIRONMENT CHANGE AND FLOOD CATASTROPHE IN HUAIHE RIVER BASIN DURING LAST 2000 YEARS

ＧＥＯＧＲＡＰＨＩＣ ＥＮＶＩＲＯＮＭＥＮＴ ＣＨＡＮＧＥ ＡＮＤ ＦＬＯＯＤ ＣＡＴＡＳＴＲＯＰＨＥ ＩＮ ＨＵＡＩＨＥ ＲＩＶＥＲ ＢＡＳＩＮ ＤＵＲＩＮＧ ＬＡＳＴ ２０００ ＹＥＡＲＳＹａｎｇＤａｙｕａｎ（杨达源）（ＤｅｐａｒｔｍｅｎｔｏｆＧ...     

Paleo-fluvial sedimentation on the outer shelf of the East China Sea during the last glacial maximum

Evidence from lithology, foraminiferal assemblages, and high-resolution X-ray fluorescence scanning data of core SFK-1 indicates tidally influenced paleo-fluvial sedimentation during the last glacial maximum (LGM) on the outer shelf of the East China Sea. The paleo-fluvial deposits consist of river channel facies and estuarine incised-valley-filling facies. Different reflections on the seismic profile across core SFK-1 suggest that the river channels shifted and overlapped. River channel deposition formed early in the LGM when sea level fell and the estuary extended to the outer shelf. Channel sediments are yellowish-brown in color and rich in foraminifera and shell fragments owing to the strong tidal influence. Following the LGM, the paleo-river mouth retreated and regressive deposition of estuarine and incised-valley-filling facies with an erosion base occurred. The river channel facies and estuarine incised-valley-filling facies have clearly different sedimentary characteristics and provenances. The depositional environment of the paleoriver system on the wide shelf was reconstructed from the foraminiferal assemblages, CaCO₃ content and Ca/Ti ratio. The main results of this study provide further substantial constraints on the recognition of late Quaternary stratigraphy and land-sea interactions on the ECS shelf.     

Interdecadal variations of surface winds over China marginal seas

Long term variability in the surface winds over the marginal seas of China is examined with a dominant-mode singular value decomposition method. Both interannual and interdecadal patterns are found to be seasonally and spatially dependent, with reanalyses and satellite remote sensing data yielding highly consistent results. The study reveals that summer monsoon winds over the East China Sea experienced an interdecadal weakening in the late 1960s and began a persistent recovery in 2005. The study also shows gradual weakening of the winter monsoon in the southern South China Sea by more than 2m/s since the 1960s, with corroboration from coastal climate stations in Borneo. This phenomenon has not been reported in previous monsoon studies.     

Agriculture development-induced surface albedo changes and climatic implications across northeastern China

To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model.Essential natural vegetation records compiled from historical documents and regional optimal surface albedo dataset were used.The results show that the surface albedo decreased by 0.01-0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005-0.015 due to conversions from forests to cropland in the surrounding mountains.As a consequence,in the Northeast China Plain,the surface net radiation increased by 4-8 W/m 2,2-5 W/m 2,and 1-3 W/m 2,and the climate was therefore warmed by 0.1℃-0.2℃、0.1℃-0.2℃、 0.1℃-0.3 ℃ in the spring,autumn and winter,respectively.In the surrounding mountain area,the net radiation decreased by less than 1.5 W/m 2,and the climate was therefore cooled too slight to be detected.In summer,effects of surface albedo changes on climate were closely associated with moisture dynamics,such as evapotranspiration and cloud,instead of being merely determined by surface radiation budget.The simulated summer climatic effects have large uncertainties.These findings demonstrate that surface albedo changes resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the climatic effects in summer could hardly be concluded so far.     

Spatial and temporal variations of Synechococcus and picoeukaryotes in the Taiwan Strait,China

The size-fractionated phytoplankton biomass, and the spatial and temporal variations in abundance of Synechococcus (SYN) and picoeukaryotes (PEUK) were measured in the Taiwan Strait during three cruises (August 1997, February-March 1998, and August 1998). The results show that picophytoplankton and nanophytoplankton dominate the phytoplankton biomass, in average of 38% and 40%, respectively. SYN and PEUK varied over time in abundance and carbon biomass, greater in summer than in winter, in range of (7.70–20...     

青藏高原西南部塔若错湖泊沉积物记录的近300年来气候环境变化

以青藏高原西南部塔若错的34cm浅湖芯为研究对象,对其沉积物样品进行总有机碳、无机碳、总氮、微量元素、正构烷烃含量及碳氮比等多项指标的分析测定。采用过剩210 Pb和137 Cs计年法对该湖芯进行了定年和沉积速率研究,获得了近300年的连续湖泊沉积环境序列。在明确了各指标气候环境指示意义的前提下,综合对比分析湖芯中各项气候环境指标,并结合定年结果重建了塔若错湖区近300年来的气候环境变化。结果表明:塔若错湖区气候环境变化可分为3个明显阶段:早期为1705～1778年,该地区气候环境温暖湿润,湖区植被广泛发育;中期为1778～1860年,湖区处于小冰期末次阶段,气候环境寒冷而湿润,植被发育受阻;后期为1860年至今,为小冰期结束后偏暖干化时期。其中,后期又可分为3个亚阶段:1860～1924年,湖区气候环境稍暖且干旱,植被稍有发育;1924～1969年,湖区气候环境呈现偏冷干特点,植被发育暂缓;1969年至今,湖区气候回暖,环境干旱化有所缓解,植被开始逐渐发育。在气候冷暖变化上,该湖芯记录与古里雅冰芯记录和青海湖湖泊沉积记录都有较好的可对比性,只是在起讫年代上存在一些差异。     

Formation and evolution of the modern warm current system in the East China Sea and the Yellow Sea since the last deglaciation

To reconstruct the formation and evolution process of the warm current system within the East China Sea (ECS) and the Yellow Sea (YS) since the last deglaciation, the paleoceangraphic records in core DGKS9603, core CSH1 and core YSDP102, which were retrieved from the mainstream of the Kuroshio Current (KC), the edge of the modern Tsushima Warm Current (TWC) and muddy region under cold waters accreted with the Yellow Sea Warm Current (YSWC) respectively, were synthetically analyzed. The results indicate that the formation and evolution of the modern warm current system in the ECS and the YS has been accompanied by the development of the KC and impulse rising of the sea level since the last deglaciation. The influence of the KC on the Okinawa Trough had enhanced since 16 cal kyr BP, and synchronously the modern TWC began to develop with the rising of sea level and finally formed at about 8.5 cal kyr BP. The KC had experienced two weakening process during the Heinrich event 1 and the Younger Drays event from 16 to 8.5 cal kyr BP. The period of 7–6 cal kyr BP was the strongest stage of the KC and the TWC since the last deglaciation. The YSWC has appeared at about 6.4 cal kyr BP. Thus, the warm current system of the ECS and the YS has ultimately formed. The weakness of the KC, indicated by the occurrence of Pulleniatina minimum event (PME) during the period from 5.3 to 2.8 cal kyr BP, caused the main stream of the TWC to shift eastward to the Pacific Ocean around about 3 cal kyr BP. The process resulted in the intruding of continent shelf cold water mass with rich nutrients. Synchronously, the strength of the YSWC was relatively weak and the related cold water body was active at the early-mid stage of its appearance against the PME background, which resulted in the quick formation of muddy deposit system in the southeastern YS. The strength of the warm current system in the ECS and the YS has enhanced evidently, and approached to the modern condition gradually since 3 cal kyr BP. Supported by the National Natural Science Foundation of China (Nos. 90411014 and 40506015), the National major Fundamental Research and Development Project (No. 2007CB815903) and the CAS Pilot Project of the National Knowledge Innovation Program (No. KZCFX3-SW-233)     

遥感降水产品在中国不同气候区的适用性研究

遥感降水产品相对于气象站观测数据能够更好地反映降水的空间分布特征,对其进行不同气候区上的差异性评价对数据产品选择和遥感降水反演算法改进均有重大意义.本文选择中国典型气候区(干旱区、过渡区、湿润区和青藏高原地区),以649个经偏差矫正后的气象站降水数据为标准,评估了5种国际常用的遥感降水产品(CHIRPS v2.0,CM...     

Influence of the Convection over the South China Sea on the Summer Precipitation of Shandong Province

1　Introduction　ShandongProvince ,whichislocatedintheeastofChina ,consistspartlyofpeninsulaandpartlyofinlandwithatotalareaofabout 1 5 0 0 0 0km2 .Lyingfrom34°2 0′Nto 38°2 0′Nandfrom 1 1 4°4 0′Eto 1 2 2°4 0′E ,alltheareabelongstothemoderateregionandtothetypicalAsianmonsoonclimate .SoShandong’ssum merprecipitationaccountsforover 6 0 %oftheannualrainfall,andaccordinglyflood droughtdisastersmain lyoccurinsummer.Moreover,becauseitisgeographi callylocatedinthetransitionalareabetweenthe…