CAS Institute of Tibetan Plateau Research

Beijing, China

CAS Institute of Tibetan Plateau Research

Beijing, China
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Human life and the entire ecosystem of South East Asia depend upon the monsoon climate and its predictability. More than 40% of the earths population lives in this region. Droughts and floods associated with the variability of rainfall frequently cause serious damage to ecosystems in these regions and, more importantly, injury and loss of human life. The headwater areas of seven major rivers in SE Asia, i.e. Yellow River, Yangtze, Mekong, Salween, Irrawaddy, Brahmaputra and Ganges, are located in the Tibetan Plateau. Estimates of the Plateau water balance rely on sparse and scarce observations that cannot provide the required accuracy, spatial density and temporal frequency. Fully integrated use of satellite and ground observations is necessary to support water resources management in SE Asia and to clarify the roles of the interactions between the land surface and the atmosphere over the Tibetan Plateau in the Asian monsoon system. The goal of this project is to: 1. Construct out of existing ground measurements and current / future satellites an observing system to determine and monitor the water yield of the Plateau, i.e. how much water is finally going into the seven major rivers of SE Asia; this requires estimating snowfall, rainfall, evapotranspiration and changes in soil moisture; 2. Monitor the evolution of snow, vegetation cover, surface wetness and surface fluxes and analyze the linkage with convective activity, (extreme) precipitation events and the Asian Monsoon; this aims at using monitoring of snow, vegetation and surface fluxes as a precursor of intense precipitation towards improving forecasts of (extreme) precipitations in SE Asia. A series of international efforts initiated in 1996 with the GAME-Tibet project. The effort described in this proposal builds upon 10 years of experimental and modeling research and the consortium includes many key-players and pioneers of this long term research initiative.

Hou J.,CAS Institute of Tibetan Plateau Research | D'Andrea W.J.,Lamont Doherty Earth Observatory | Liu Z.,University of Hong Kong
Quaternary Science Reviews | Year: 2012

There is a great deal of controversy regarding the fate of glaciers and ice fields on the Tibetan Plateau in the face of continued anthropogenic global warming. Paleoclimate reconstructions and spatial analyses aimed at mapping past climate changes are the key to understanding the climatic response of the Tibetan Plateau to changing conditions. Specifically, the numerous lakes distributed across the Tibetan Plateau can provide high-resolution (spatial and temporal) climate reconstructions to investigate past changes in the climate system. In this paper, we review the primary limitation to exploiting these valuable paleoclimate archives: errors in radiocarbon-based age models. We review the techniques that have been used to estimate 14C reservoir ages on the Tibetan Plateau and compile the published 14C reservoir ages to examine their spatial and temporal patterns and to assess the imposed chronological uncertainties. Using site-specific evaluations of Bangong Co and Lake Qinghai, we demonstrate that 14C age model uncertainties permit equally probable and contrasting interpretations of existing paleoclimate records. We also examine 14C-induced uncertainties in the spatial climatic response on the Tibetan Plateau to (1) the termination of the Last Glacial Maximum and (2) the Holocene Thermal Maximum. We conclude with recommendations for reducing uncertainties in future lake-based paleoclimate studies on the Tibetan Plateau. © 2012 Elsevier Ltd.

Gao Y.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Cuo L.,CAS Institute of Tibetan Plateau Research | Zhang Y.,U.S. National Center for Atmospheric Research
Journal of Climate | Year: 2014

Changes in moisture as represented by P - E (precipitation 2 evapotranspiration) and the possible causes over the Tibetan Plateau (TP) during 1979-2011 are examined based on the Global Land Data Assimilation Systems (GLDAS) ensemble mean runoff and reanalyses. It is found that the TP is getting wetter as a whole but with large spatial variations. The climatologically humid southeastern TP is getting drier while the vast arid and semiarid northwestern TP is getting wetter. The Clausius-Clapeyron relation cannot be used to explain the changes in P - E over the TP. Through decomposing the changes in P - E into three major components-dynamic, thermodynamic, and transient eddy components-it is noted that the dynamic component plays a key role in the changes of P - E over the TP. The thermodynamic component contributes positively over the southern and central TP whereas the transient eddy component tends to reinforce (offset) the dynamic component over the southern and parts of the northern TP (central TP). Seasonally, the dynamic component contributes substantially to changes in P - E during the wet season, with small contributions from the thermodynamic and transient eddy components. Further analyses reveal the poleward shift of the East Asian westerly jet stream by 0.7° and poleward moisture transport as well as the intensification of the summer monsoon circulation due to global warming, which are shown to be responsible for the general wetting trend over the TP. It is further demonstrated that changes in local circulations that occur due to the differential heating of the TP and its surroundings are responsible for the spatially varying changes in moisture over the TP. © 2014 American Meteorological Society.

Agency: European Commission | Branch: FP7 | Program: CSA-CA | Phase: SPA.2012.1.3-02 | Award Amount: 2.78M | Year: 2013

CORE-CLIMAX will coordinate the identification of available physical measurements, which can be reconciled with previously existing data records, to form long time series. It will help to substantiate how GMES observations and products can contribute to climate change analyses, by establishing the extent to which GMES observations complement existing Climate Data Records (CDR). With GCOS, GMES and ESA CCI projects, and EUMETSAT including its Satellite Application Facility (SAF) network, coordination will also take place with specific efforts to be undertaken by new FP7 GMES projects to further upgrade their product catalogues to include this climate relevant validation and information and lay the observational basis for service activities. CORE-CLIMAX will identify the integration of ECVs into the reanalysis chain by proposing a feedback mechanism ensuring that the results of the re-analysis process get appropriately reflected into updates of the ECVs. Together with intercomparing different reanalyses, CORE-CLIMAX will contribute to establish a European truly coupled gridded re-analysis which incorporates full exchanges and interactions between atmosphere, ocean, land, including the hydrological cycle. Specific objectives: 1 Coordinate with GMES ongoing activities and contribute to the formulation of the GMES climate service theme (GCOS, FP7 GMES and climate change projects, ESA CCI projects, EUMETSAT including its SAF network and EUMETNET as part of the European Meteorological Infrastructure) 2 Propose a structured process for delivering ECVs through the stepped and quality controlled elaboration of CDR, the latter being derived from prioritisation of the most appropriate input data sets; 3 Propose a validation process aiming at qualifying the accuracy of the climate variables; 4 Propose a feedback mechanism ensuring that the results of the re-analysis process get appropriately reflected into updates of the CDR; 5 Propose a process to compare reanalyses.

Nie J.,Lanzhou University | Nie J.,CAS Institute of Tibetan Plateau Research
Geochemistry, Geophysics, Geosystems | Year: 2011

Earth's climate over the last one million years experienced several ∼100-kyr glacial cycles, but no simple forcing mechanism has been identified. Numerous studies have tried to explain strong 100-kyr glacial cycles without recognizable forcing, which has come to be known as the 100-kyr problem. Few studies have examined 100-kyr band paleoclimatic signals before 1 Ma. A recent study has demonstrated that benthic oxygen and carbon isotope records are phase-locked and amplitude-coupled at the 100-kyr band, but that neither is phase-locked to and amplitude-coupled with the 100-kyr eccentricity signal between 3 and 1 Ma. This phasing and amplitude mismatch of the 100-kyr band between 3 and 1 Ma between marine records and the eccentricity forcing signal has been called the "late Pliocene-early Pleistocene 100-kyr problem." However, it remains unknown whether terrestrial paleoclimate records are consistent with marine records at the 100-kyr band. Here I show that loess monsoon records from China are amplitude-coupled with benthic oxygen and carbon isotope records at the 100-kyr band, but not with the 100-kyr eccentricity forcing between 3 and 1 Ma. This observation provides further evidence in support of a free 100-kyr oscillation as the cause of the 100-kyr band amplitude variability in paleoclimatic records between 3 and 1 Ma. In contrast, benthic oxygen isotope records and loess monsoon records at the 100-kyr band are not amplitude-coupled with 100-kyr benthic carbon isotope records over the last 0.4 million years, indicating that the late Pleistocene 100-kyr climatic cycles may not result exclusively from a free oscillation. Copyright 2011 by the American Geophysical Union.

Zeng L.,Chinese Academy of Geological Sciences | Gao L.-E.,Chinese Academy of Geological Sciences | Xie K.,CAS Institute of Tibetan Plateau Research | Liu-Zeng J.,CAS Institute of Tibetan Plateau Research
Earth and Planetary Science Letters | Year: 2011

Within the Himalayan collisional belt, granotoids occur along two sub-parallel belts, the Northern Himalayan Gneiss Domes (NHGD) and the High Himalayan Crystalline Series (HHCS). In the Yardoi area of NHGD, two-mica granite, a new type granite occurs in the core of the Yardoi gneiss dome (YGD), Dala and Quedang from north to south, and extends at least 50km long. These granites have similar mineral composition, elemental and radiogenic isotope geochemistry, and age of formation. SHRIMP zircon U/Pb dating indicates that the Yardoi and the Quedang two-mica granites formed at 42.6±1.1Ma and 42.8±0.6Ma, respectively, similar to the Dala pluton. These two-mica granites have (1) high SiO2 (>68wt.%), Al2O3 (>15wt.%), and A/CNK(>1.0); (2) relatively high Sr and LREE, but low Y(<10ppm) and Yb (<1ppm); (3) high Sr/Y (>40 and up to 250) and La/Yb (>30); (4) very weak or no Eu anomalies; and (5) as compared with those in the Himalayan leucogranites, low initial Sr (87Sr/86Sr(i)<0.7120) and similarly unradiogenic Nd (εNd(i)=-8.9--15.0) isotopic compositions. These granites have initial Sr and Nd isotope compositions similar to those in the amphibolites but significantly different from those in the metapelite and granitic gneiss. Two-mica granites from the Yardoi area are of peraluminous granite with relatively high Na/K and Sr/Y ratios. Such features are distinct from those in the younger leucogranites along the HHCS as well as in the NHGD, and require melting of source consisting dominantly of amphibolite at thickened crustal conditions. This is also supported by the presence of amphibolites with similar Sr and Nd isotope compositions, and similar ages of metamorphism. Two-mica granites of similar age also occur in the other NHGD gneiss domes and along the HHCS belt, implying that Mid-Eocene melting of thickened crustal materials was widespread and might be a primary factor that led to the formation of high density materials (e.g. eclogitic rocks) beneath the Tethyan Himalaya. © 2011 Elsevier B.V.

The behaviour of rare earth elements (REEs) and yttrium (Y) during chemical weathering processes has been investigated on a 4.05 m thick terra rossa profile over dolomite on the Yunnan-Guizhou Plateau, China. In this profile, ferromanganese concretions and gibbsite spots coexist in the terra rossa solum. Analyses of REEs, Y, Zr, F, S, and TOC, as well as mineralogical studies, were conducted on a suite of ferromanganese concretions, gibbsite spots, terra rossas, dolomites, and insoluble residues from the underlying dolomite. These analyses helped us to understand the mobilization, redistribution, and fractionation of REEs and Y during chemical weathering. The REEs and Y are mobilized and redistributed during the terra rossa formation. REEs, except for Ce, are removed from the upper and middle profiles, transferred downwards, and then precipitated in the base profile, resulting in remarkable enrichment in the terra rossa near the weathering front. The significant increase of pH near the weathering front was responsible for REE (excluding Ce) and Y enrichment in the base profile. Y is quite mobile during extreme chemical weathering, and most of it was carried away from the profile. Because of very efficient oxidative fractionation of Ce, a significant positive Ce anomaly in terra rossa was found in the middle of the profile, whereas the terra rossa near the weathering front exhibited notably negative Ce anomalies. Moreover, the presence of cerianite and its content in the ferromanganese concretions can explain the markedly positive Ce anomaly and the variation of Ce/Ce * values with depth. In profile, these Ce anomalies are characteristic of the geochemical environment, especially the redox condition. Studies of REE distribution in the ferromanganese concretions, gibbsite spots, and surrounding terra rossa revealed that significant REE fractionation occurred. REEs and Y were preferentially concentrated in the ferromanganese concretions rather than in the gibbsite spots. The water-rock interaction resulted in M-type tetrad effects in some of the ferromanganese concretions, gibbsite spots, and terra rossa samples. In addition, the tetrad effect in terrestrial weathering processes likely played an important role in the fractionation of REEs and Y, such as Y-Ho, Sm-Nd, and the Eu anomaly change. © 2010 Elsevier B.V. All rights reserved.

Xu X.,CAS Institute of Tibetan Plateau Research | Yi C.,CAS Institute of Tibetan Plateau Research
Global and Planetary Change | Year: 2014

Knowledge of the Little Ice Age (LIA) on the Tibetan Plateau (TP) is of critical importance for understanding the climate changes over the past millennium. However, the data associated with the extents and chronologies of TP LIA moraines are highly dispersed in literature. Lack of systematic integration of these data hampers us to further understand the nature of the LIA, especially from a perspective of whole TP. The paper reviews multiple types of dating on LIA moraines to examine the timing and nature of the LIA on the TP. These include ages of radiocarbon 14C, lichenometry, and cosmogenic radionuclide (CRN), by which we can cross-date the same or morphostratigraphically similar landforms. LIA moraines on the TP are usually present a few hundred to thousand meters beyond the contemporary glaciers. The morphological and stratigraphic evidence indicates multiple periods of glacier advance during the last millennium (LIA). At present, available chronology evidence allows to fully compare the timing of the LIA maximum extents. The glaciers reached and retreated from their LIA maximum extents by an asynchronous pattern between different parts of the TP. The majority of glaciers advanced to their LIA maximum extents at late-14th and early-14th century on the southern and northwestern TP, respectively. The glaciers retreated from their LIA maximum extents during 16th to early-18th, late-14th to early-15th and early-16th century on the southern, northwestern, and northeastern TP, respectively. In addition, the glacier advance period of late-18th to early-19th centuries and retreat period of late-19th century are common on the whole TP. Comparison with ice core records suggests that on the TP, the glacier fluctuations responded more strongly to temperature than to precipitation. By comparison of the LIA chronologies from a global perspective, this paper also concludes that the LIA maximum extents occurred commonly earlier on the TP than in North Atlantic and Southern Hemisphere regions, despite of the variability in the timing of LIA maximum extents on the TP and in the North Atlantic regions. Further, more chronology programs, especially in the central TP, are necessarily needed to improve our understanding of the LIA glacier fluctuations. © 2014 Elsevier B.V.

The mobilization, redistribution and fractionation of trace elements during chemical weathering processes have been investigated on a 4.05. m thick terra rossa profile overlying dolomite on the Yunnan-Guizhou Plateau, in Southwest China. In this in situ weathering profile, the ferromanganese concretions and the gibbsite spots coexist in the terra rossa saprolite. The mass-balance evaluation reveals that titanium, Nb and Hf in the terra rossa matrix are conservative elements during chemical weathering compared to Zr. The elements of Li, Sc, V, Cr, Fe, Ga, As, Mo, Cs, Ce, Ta, Tl, Pb and Th in the terra rossa matrix include additions from external sources. Beryllium, Mn, Co, Ni, Cu, Rb, Ba and La are depleted in the shallow parts of the terra rossa profile and enriched in the deep parts. The elements of Zn, Sr, Y, Cd, Sn and U in the terra rossa profile are lost during weathering. Compared to the terra rossa matrix, the ferromanganese concretions are significantly enriched in most trace elements, especially Mn, Co, Cd, Ce, Tl and Pb. In contrast, the gibbsite spots are depleted in all trace elements, except for U. The results regarding specific inter-element relationships indicate that most trace elements have different inter-element relationships in the ferromanganese concretions, the gibbsite spots and the terra rossa matrix. This suggests that the behavior of many trace elements during mobilization and redistribution differs from their behavior during incorporation into secondary mineral phases, especially the Mn and Fe oxides and/or oxyhydroxides in the ferromanganese concretions. It is worthy to note that the fractionation between Ce and Mn occurs under intensive chemical weathering conditions. Correspondingly, beryllium exhibits a similar geochemical behavior as that of rare earth elements (except for Ce) and Y during surface weathering. © 2010 Elsevier B.V.

Cai F.,CAS Institute of Tibetan Plateau Research | Ding L.,CAS Institute of Tibetan Plateau Research | Yue Y.,CAS Institute of Tibetan Plateau Research
Earth and Planetary Science Letters | Year: 2011

The provenance of upper Cretaceous strata in the Tethys Himalaya provides critical constraints on the closure time of the Neo-Tethys Ocean and the initial India-Asia collision. This paper reports detailed petrographic studies, in-situ detrital zircon U-Pb ages and Lu-Hf isotopic analyses, whole rock Nd-isotopes, and Cr-spinel electronic microprobe data from upper Cretaceous clastic sedimentary rocks of the Tethys Himalaya near Gyangze, southern Tibet. The Berriasian-Coniacian Jiabula Formation consists of black mudstone, chert and minor quartz arenite, and is dominated by detrital zircons with Archean-Cambrian U-Pb ages which were most likely derived from the Indian continent. Overlying conformably is the Santonian-Maastrichtian Chuangde Formation, which consists of red shale, limestone and chert. The Chuangde Formation is in turn overlain by the late Maastrichtian-late Paleocene Zongzhuo Formation, which is composed of black mudstone and lithic sandstone enclosing various olistoliths of sandstone, limestone and chert. The Rilang conglomerate is a lens which is located within the upper part of the Zongzhuo Formation and consists of an upward-thinning and fining succession of volcanic conglomerate, sandstone and black mudstone. The Zongzhuo Formation and the Rilang conglomerate record an abrupt influx of Cretaceous zircon grains with juvenile Hf isotopic compositions, arc-related Cr-spinels and positive εNd(0) sediments, suggesting an arc and suture-zone provenance. The change in provenance of upper Cretaceous strata from the southern Indian continent to a northern arc and suture zone is attributed to either (1) initial collision between the Indian plate and Lhasa terrane, or (2) initial collision between the Indian plate and an intra-oceanic arc. We prefer option (1) that the initiation of India-Asia collision occurred during Maastrichtian (~70-65Ma). © 2011 Elsevier B.V.

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