Effects of surface heating on precipitation over the Tibetan Plateau and its eastern margin

The high terrain of the Tibetan Plateau(TP)has a very important impact on the weather and climate of China,East Asia,South Asia,and even the Northern Hemisphere.However,in recent years,the reasons for the decrease in precipitation in the southeastern edge of the plateau have resulted in cutting-edge research regarding the impact of the TP and its surrounding areas on downstream weather and climate.In this study,the spatial and temporal distribution of surface heat flux and precipitation were analyzed from 1998 to 2022,and the possible mechanism of the decrease of precipitation in the eastern edge of the plateau is explored.The main conclusions are as follows:The annual average sensible heat flux in the TP and its east side is positive,with an average of 33.73 W/m^(2).The annual average latent heat flux is positive,with an average of 42.71 W/m^(2).Precipitation has a similar annual average and seasonal distribution,with modest amounts in the northwest and substantial amounts in the southeast.The average annual accumulated precipitation is 670.69 mm.The first mode of the Empirical Orthogonal Function(EOF)shows that sensible heat flux decreases first,then increases,and then finally decreases during 1998–2022.The modes show the opposite trend in middle part of the plateau.The latent heat flux initially decreases,then increases,and finally decreases in the western plateau and near Sichuan Basin.The mode,however,displays the opposite tendency throughout the rest of the region.The precipitation in the north and south sides of the plateau has decreased since 2013,which is consistent with the changing trend of sensible heat flux.In the rest of the region,the change trend is not obvious.The sensible heat of the main body of the plateau and its east side and Sichuan Basin is negatively correlated with precipitation,that is,when sensible heat flux of the main body of the plateau and its east side and Sichuan Basin is more(less),local precipitation is less(more).The latent heat of the main body of the plateau and its east side,Sichuan Basin is positively correlated with precipitation,indicating that when latent heat flux of the main body of the plateau and its east side,Sichuan Basin is more(less),local precipitation is more(less).

Influence of South Asian Biomass Burning on Ozone and Aerosol Concentrations Over the Tibetan Plateau

In this work,the influence of South Asian biomass burning emissions on O_(3) and PM_(2.5)concentrations over the Tibetan Plateau(TP)is investigated by using the regional climate chemistry transport model WRF-Chem.The simulation is validated by comparing meteorological fields and pollutant concentrations against in situ observations and gridded datasets,providing a clear perspective on the spatiotemporal variations of O_(3) and PM_(2.5)concentrations across the Indian subcontinent,including the Tibetan Plateau.Further sensitivity simulations and analyses show that emissions from South Asian biomass burning mainly affect local O_(3) concentrations.For example,contribution ratios were up to 20%in the Indo-Gangetic Plain during the pre-monsoon season but below 1%over the TP throughout the year 2016.In contrast,South Asian biomass burning emissions contributed more than 60%of PM_(2.5)concentration over the TP during the pre-monsoon season via significant contribution of primary PM_(2.5)components(black carbon and organic carbon)in western India that were lofted to the TP by westerly winds.Therefore,it is suggested that cutting emissions from South Asian biomass burning is necessary to alleviate aerosol pollution over the TP,especially during the pre-monsoon season.

Cryosphere evapotranspiration in the Tibetan Plateau:A review

Land surface actual evapotranspiration is an important process that influences the Earth's energy and water cycles and determines the water and heat transfer in the soil-vegetation-atmosphere system.Meanwhile,the cryosphere's hydrological process is receiving extensive attention,and its water problem needs to be understood from multiple perspectives.As the main part of the Chinese cryosphere,the Tibetan Plateau faces significant climate and environmental change.There are active interaction and pronounced feedback between the environment and ETa in the cryosphere.This article mainly focuses on the research progress of ETa in the Tibetan Plateau.It first reviews the ETa process,characteristics,and impact factors of typical underlying surfaces in the Tibetan Plateau(alpine meadows,alpine steppes,alpine wetlands,alpine forests,lakes).Then it compares the temporal and spatial variations of ETa at different scales.In addition,considering the current greening of cryosphere vegetation due to climate change,it discusses the relationship between vegetation greening and transpiration to help clarify how vegetation activities are related to the regional water cycle and surface energy budget.

Research progress on behaviors and environmental effects of mercury in the cryosphere of the Tibetan Plateau:a critical review

The behavior and fates of environmental pollutants within the cryosphere and the associated environmental impacts are of increasing concerns in the context of global warming.The Tibetan Plateau(TP),also known as the"Third Pole",represents one of the most important cryospheric regions in the world.Mercury(Hg)is recognized as a global pollutant.Here,we summarize the current knowledge of Hg concentration levels,pools and spatio-temporal distribution in cryospheric environments(e.g.,glacier,permafrost),and its transfer and potential cycle in the TP cryospheric region.Transboundary transport of anthropogenic Hg from the surrounding heavily-polluted regions,such as South and Southeast Asia,provides significant sources of atmospheric Hg depositions onto the TP cryosphere.We concluded that the melting of the cryosphere on the TP represents an increasing source of Hg and brings a risk to the TP environment.In addition,global warming acts as an important catalyst accelerating the release of legacy Hg from the melting cryosphere,adversely impacting ecosystems and biological health.Furthermore,we emphasize on the remaining gaps and proposed issues needed to be addressed in future work,including enhancing our knowledge on some key release pathways and the related environmental effects of Hg in the cryospheric region,integrated observation and consideration of Hg distribution,migration and cycle processes at a key region,and uses of Hg isotopic technical and Hg models to improve the understanding of Hg cycling in the TP cryospheric region.

The Growth of Two Species of Subalpine Co-nifer Saplings in Response to Soil Warming and Inter-Competition in Mt. Gongga on the South-Eastern Fringe of the Qinghai-Tibetan Plateau, China

In conjunction with global climate change, soil temperatures have been recorded to be increasing more rapidly than air temperatures at Mt. Gongga, China. Plant density is also increasing, and a means of combining the effects of changes in soil temperature and competition on the growth and regeneration of the constructive coniferous species seedlings in the subalpine ecotones is needed. Thus, a split-plot design experiment was conducted with Sargent spruce (Picea brachytyla) and Purple cone spruce (P. purpurea) saplings, using four soil temperatures (control Tsoil = 11.9℃ ± 0.3℃, low Tsoil = 13.4℃ ± 0.140℃, intermediate Tsoil = 15.4℃ ± 0.1℃, high Tsoil = 16.4℃ ± 0.2℃) and three plant densities (one, two and three saplings per pot), in the subalpine ecotone. Soil temperatures were controlled through a cable heating system. After two growing seasons under the soil temperature treatments, 107 Sargent spruce saplings and 110 of the same-aged Purple cone spruce saplings were harvested. The results showed that Sargent spruce grew faster and with a greater biomass productivity than Purple cone spruce. Increased soil temperature significantly increased leaf biomass, branch biomass, above-ground biomass, and total plant biomass for developing crown architecture in Sargent spruce, whereas plant competition (i.e., higher density) notably caused a decline in leaf biomass, branch biomass, and above-ground biomass. Purple cone spruce did not respond to either an increases in soil temperature or plant competition. Neither plant species was influenced by the interaction of soil temperature and plant competition. These results suggest that Sargent spruce may expand the upper and lower limits of its distribution as global warming continues, but the expansion is likely to be restricted by plant competition in the future, including that from Purple cone spruce. Below-ground, fine root biomass does not change with soil warming although other sized roots do in both species. This signifies that light availability is more important in the acclimation of Sargent spruce to the changing environments than soil nutrient availability. Purple cone spruce is unaffected by the complex changing environment, suggesting that this spruce may stably grow and continue to thrive in the subalpine ecotone in future scenarios of climate change.

Sequestration of carbon as carbonate in the critical zone：insights from the Himalayas and Tibetan Plateau

The carbon pool stored in soil carbonate is comparable to the soil organic carbon.Therefore,secondary calcite precipitation in supersaturated catchment could be an important,yet poorly constrained,carbon sink within the modern global carbon cycle.The chemical analysis of some dissolved species transported by rivers,such as elevated Sr/Ca and Mg/Ca ratios but also heavy stable Ca isotopic compositions,witness the formation of secondary calcite in rivers draining arid regions.However,in areas affected by active tectonics and rapid physical erosion,co-variations in the fluvial Sr/Ca and Mg/Ca ratios could also be related to incongruent carbonate weathering processes.Here,we present a model to assess the roles played by incongruent carbonate dissolution and secondary calcite precipitation in modern weathering processes.We tested and applied the model to rivers draining the Himalayan–Tibetan region.The results suggest that regional aridity in the drainage basin promotes carbon sequestration as secondary carbonate but that for a given runoff,incongruent dissolution of carbonate possibly related to rapid physical erosion amplifies such sequestration.The isotopic compositions(^(13)C/^(12)C and^(18)O/^(16)O)of detrital carbonate transported by the main rivers in South and South-East Tibet imply that around 1%of the suspended material transported by those rivers corresponds to secondary carbonate and can represent between 5%and 15%of the alkalinity flux.Most of these alkalinity transported as particulate material is,nevertheless related to the weathering of carbonate lithologies and is also subjected to dissolution prior its final storage in sedimentary basins.However,on glacial-interglacial timescale this will amplify the significant role of mountain weathering on climatic variations.

Determination of Land Surface Heat Fluxes at Different Temporal Scales over the Tibetan Plateau

Surface energy budget components(such as net radiation flux,sensible heat flux,latent heat flux and soil heat flux)at multiple temporal scales have significant meaning for understanding the energy and water cycle over the Tibetan Plateau(TP).In the framework of ESA-MOST Dragon Programme 4,the surface energy balance system(SEBS)was tested and used to derive surface heat fluxes at different temporal scales over the TP by a combination use of geostationary satellite(FY-2 C)data,polar orbiting satellite(SPOT/VGT,Terra/MODIS)data and ITPCAS forcing data.The validation results show there is a good agreement between derived heat fluxes and in situ measurements from Third Pole Environment Observation and Research Platform(TPEORP),which means the feasibility to derive surface heat fluxes over heterogeneous landscapes by a combination use of geostationary and polar orbiting satellite data in SEBS.The diurnal,seasonal and inter-annual variation characteristics were also clearly identified through analyses of derived turbulent fluxes.

Atmospheric insight to climatic signals of δ^18O in a Laohugou ice core in the northeastern Tibetan Plateau during 1960–2006

Ice documentation and response to prominent warming, especially after the 1990s, is further investigated because it is concerned whether ice records have absence. A δ^18O series of a Laohugou （LHG） shallow ice core （20.12 m） in the northeastern Tibetan Plateau was reconstructed covering the period of 1960–2006. The ice core δ^18O record had sig-nificant positive correlations with the warm season （May–September） air temperatures at adjacent meteorological stations and the 500 hPa temperatures in boreal China, indicating that the δ^18O record could be considered a credible proxy of regional temperature. A clear, cold temperature event in 1967 and rapid warming after the 1990s were captured in the LHG δ^18O series, revealing that it could record extreme air-temperature events on both regional and global scales. The LHG δ^18O variations had evident positive correlations with both the summer surface outgoing longwave radiation （OLR） in the Mongolia region and the summer meridional wind at 500 hPa in the LHG region during 1960–2006, suggesting that the increased OLR in the Mongolia region might have intensified the Mongolia Low and expanded the pressure gradient to the LHG region （the Shulehe High）, which would have pushed the westerlies further north and suppressed southward incursions of cold air into the LHG region, and thus augmented the temperature rise. The regional atmospheric circulation difference （1985–2006 minus 1960–1984） suggested that the anticyclone in the Mongolia region might have developed the easterly wind, which transported warmer air from the east toward the LHG region and weakened the cold penetration of the westerlies, resulting in the temperature rise since the middle 1980s.

Experimental and theoretical study of mechanical properties of root-soil interface for slope protection

Plant roots mechanically enhance the strength of soil and improve slope stability through anchoring.Given the popularization of ecological slope-protection technology,a quantitative study of how roots help to anchor soil is highly pertinent.The object of the present study is thus to investigate how roots and soil combine to affect the mechanical properties of the root-soil interface.Toward this end,pullout experiments of cedar roots of different diameters in soils of different density were conducted.The experimental results show that the maximum pullout force increases significantly with increasing root diameter,but only slightly increases with increasing soil density,which indicates that the root diameter has a greater impact on the maximum pullout force than soil density.Next,based on studies of fiber-reinforced composites,a root-soil pull-out model was proposed to study the evolution of shear stress on root-soil interface.This approach ensures that the model accurately reflects the dynamic stress distribution evolution at the root-soil interface and can calculate the pullout process of embedded root from soil.The accuracy of the model is verified by comparing the calculated results with experimental results.Finally,how soil density and root diameter affect the anchoring force was analyzed.The results indicate that the maximum anchoring force increases linearly with increasing root diameter,but nonlinearly with increasing soil density until reaching a fixed value.These results show that the root soil pull-out model has significant practical value in slope protection.

Assessment of prospective hazards resulting from the 2017 earthquake at the world heritage site Jiuzhaigou Valley, Sichuan, China

On August 8, 2017, a Ms = 7.0 magnitude earthquake occurred in the Jiuzhaigou Valley, in Sichuan Province, China(N: 33.20°, E: 103.82°). Jiuzhaigou Valley is an area recognized and listed as a world heritage site by UNESCO in 1992. Data analysis and field survey were conducted on the landslide, collapse, and debris flow gully, to assess the coseismic geological hazards generated by the earthquake using an unmanned aerial vehicle(UAV), remote-sensing imaging, laser range finders, geological radars, and cameras. The results highlighted the occurrence of 13 landslides, 70 collapses, and 25 potential debris flow gullies following the earthquake. The hazards were classified on the basis of their size and the potential property loss attributable to them. Consequently, 14 large-scale hazards, 30 medium-sized hazards, and 64 small hazards accounting for 13%, 28%, and 59% of the total hazards, respectively, were identified. Based on the variation tendency of the geological hazards that ensued in areas affected by the Kanto earthquake(Japan), Chi-chi earthquake(Taiwan China), and Wenchuan earthquake(Sichuan China), the study predicts that, depending on the rain intensity cycle, the duration of geological hazard activities in the Jiuzhaigou Valley may last over ten years and will gradually decrease for the following five to ten yearsbefore returning to pre-earthquake levels. Thus,necessary monitoring and early warning systems must be implemented to ensure the safety of residents,workers and tourists during the construction of engineering projects and reopening of scenic sites to the public.

Timing and Processes of Ore Formation in the Qingchengzi Polymetallic Orefield, Northeast China: Evidence from 40Ar/39Ar Geochronology

The Qingchengzi orefield is a large polymetallic ore concentration area in the Liaodong peninsula,northeastern China,that includes twelve Pb-Zn deposits and five Au-Ag deposits along its periphery.The ore-forming age remains much disputed,which prevents the identification of the relationship between the mineralization and the associated magmatism.In this paper,we quantitatively present the feasibility of making ore mineral 40Ar/39Ar dating and report reliable 40Ar/39Ar ages of lamprophyre groundmass,K-feldspar and sphalerite from the Zhenzigou deposit.Direct and indirect methods are applied to constrain the timing of mineralization,which plays a vital role in discussing the contribution of multistage magmatism to ore formation.The low-potassium sphalerite yielded an inverse isochron age of 232.8±41.5 Ma,which features a relatively large uncertainty.Two lamprophyre groundmasses got reliable inverse isochron ages of 193.2±1.3 Ma and 152.3±1.5 Ma,respectively.K-feldspar yielded a precise inverse isochron age of 134.9±0.9 Ma.These four ages indicate that the mineralization is closely associated with Mesozoic magmatism.Consequently,regarding the cooling age of the earliest Mesozoic Shuangdinggou intrusion(224.2±1.2 Ma)as the initial time of mineralization,we can further constrain the age of the sphalerite to 224–191 Ma.These new and existing geochronological data,combined with the interaction cutting or symbiotic relationship between the lamprophyre veins and ore veins,suggest that the Pb-Zn-Au-Ag mineralization in the Qingchengzi orefield mainly occurred during three periods:the late Triassic(ca.224–193 Ma),the late Jurassic(ca.167–152 Ma)and the early Cretaceous(ca.138–134 Ma).This polymetallic deposits are shown to have been formed during multiple events coinciding with periods of the Mesozoic magmatic activity.In contrast,the Proterozoic magmatism and submarine exhalative and hydrothermal sedimentation in the Liaolaomo paleorift served mainly to transport and concentrate the ore-forming substances at the Liaohe Group with no associated Pb-Zn-Au-Ag mineralization.

Risk assessment of glacial debris flow on alpine highway under climate change: A case study of Aierkuran Gully along Karakoram Highway

Glacial debris flows(GDFs) often occur in alpine regions that are subject to rapid climate change, and pose a serious threat to road systems. However, the ways that climate change impacts GDF risks along road systems remain poorly understood. Aierkuran Gully, located in eastern Pamir along Karakoram Highway(KKH), is a hotspot for GDF activity and climate change, and was thus selected to investigate the GDF risk to road systems under climate change conditions. Reg CM4.6 climate data for northwestern China were selected as climate projections during baseline(2011–2020) and future periods(2031–2040) under the Representative Concentration Pathway(RCP) 8.5. To reflect the coupling effect of rainfall and melt water that triggers GDF, a glacial hydrological model DETIM that considers both factors was applied to calculate the peak debris flow discharge. A FLO-2D model was calibrated based on high-quality data collected from a detailed field investigation and historical debris flow event. The FLO-2D model was used to simulate the debris flow depth and velocity during baseline and future periods under RCP8.5. The debris flow hazard was analyzed by integrating the maximum flow depth and momentum. Road structure vulnerability was further determined based on the economic value and susceptibility of hazard-affected objects. The GDF risk along KKH was assessed based on the GDF hazard and vulnerability analysis. Our results show that climate change would lead to amplified peak debris flow discharge, trigger highermagnitude GDF, and induce more severe damage and threats to the road system. Compared with the baseline period, the debris flow damage risk for culverts and bridges would increase and the areas that inundate the road and pavement would expand. Our findings provide valuable insights for the development of mitigation strategies to adapt road systems to climate change, especially in alpine regions with highly active GDFs.

Estimating the maximum impact force of dry granular flow based on pileup characteristics

The maximum normal impact resultant force(NIRF)is usually regarded as the sum of the static earth pressure of the dead zone and the dynamic impact pressure of the flowing layer.The influence of the interaction between the flowing layer and dead zone on the impact force is ignored.In this study,we classified two impact models with respect to the pileup characteristics of the dead zone.Then,we employed the discrete element method to investigate the influences of the pileup characteristics on the impact force of dry granular flow on a tilted rigid wall.If the final pileup height is equal to the critical value,the maximum NIRF can be estimated using a hydrostatic model,because the main contribution to the maximum NIRF is the static earth pressure of the dead zone.If the final pileup height is less than the critical value,however,the particles in the dead zone are squeezed along the slope surface by the impact ofthe flowing layer on the dead zone,and because of shear effects,the flowing layer causes an entrainment in the dead zone.This results in a decrease in the volume of the dead zone at the moment of maximum NIRF with increases in the slope angle.As such,the maximum NIRF mainly comprises the instant impact force of the flowing layer,so hydro-dynamic models are effective for estimating the maximum NIRF.Impact models will benefit from further study of the components and distribution of the impact force of dry granular flow.

Female preference promotes asynchronous sex evolution in Elephantiformes

性双型的特征通常被认为产生于种内争夺交配优先权的斗争。例如,现生和化石的雄性长鼻类动物具有较大的体型和较粗壮的上门齿。本研究阐释了如下现象:化石象型类动物(Elephantiformes,长鼻类的主要类群)一些性双型特征与其进化历史具有相关性,而与性别竞争并非直接相关。在中新世的葛氏铲齿象(Platybelodon grangeri)和狭齿嵌齿象(Gomphotherium angustidens)中,雄性比雌性倾向于具有进化中更进步的特征,如同雄性在进化中领先雌性一步。这种现象可能与雌性偏好的机制相耦合。在象型类动物进化的早期(繁荣期),性别选择压促使雄性比雌性产生更加显著的进步特征;然而,在它们进化的晚期(衰退期),性别选择压似乎减弱,性别的异时进化也减少。这种新的发现或许在大型有蹄类的演化过程中有一定的普遍意义,因为那些繁荣的类群中通常性双型显著,如鹿科和牛科;而衰落的类群中通常性双型不显著。

Directional seismic response to the complex topography:A case study of 2013 Lushan Ms 7.0 earthquake

Azimuthal variations in site response can provide a good insight into the site amplification and seismic conditions of geohazard occurrences.In this study,multiple directional site response methods,including D-Arias(Directional-Arias),D-SER(Directional-Shaking energy ratio),D-HVSR(Directional-Horizontal to vertical spectral ratio)and D-SSR(Directional–Standard spectral ratio),are adopted to analyse seismic data of the 2013 Lushan Ms 7.0 earthquake captured by the self-established Lengzhuguan(LZG)station which consists of the complex topography of isolated ridge,large mountain and some typical micro-reliefs.The results show that the isolated ridge could cause stronger site responses than the large mountain,and whose pronounced response direction is roughly perpendicular to its ridgeline.With the growth of elevation,the siteresonant frequency decreases.The different microreliefs on the mountain cause different site responses,which present as protruding slope>linear slope.The site response mainly exists on the surficial layer of the mountain and shows that with the increase of the distance to mountain surface,the site response gets weaker,the site resonant frequency gets higher,and the pronounced response direction is perpendicular to its ridgeline.

Improved Land Use and Leaf Area Index Enhances WRF-3DVAR Satellite Radiance Assimilation： A Case Study Focusing on Rainfall Simulation in the Shule River Basin during July 2013

The application of satellite radiance assimilation can improve the simulation of precipitation by numerical weather prediction models. However, substantial quantities of satellite data, especially those derived from low-level（surface-sensitive）channels, are rejected for use because of the difficulty in realistically modeling land surface emissivity and energy budgets.Here, we used an improved land use and leaf area index（LAI） dataset in the WRF-3 DVAR assimilation system to explore the benefit of using improved quality of land surface information to improve rainfall simulation for the Shule River Basin in the northeastern Tibetan Plateau as a case study. The results for July 2013 show that, for low-level channels（e.g., channel 3）,the underestimation of brightness temperature in the original simulation was largely removed by more realistic land surface information. In addition, more satellite data could be utilized in the assimilation because the realistic land use and LAI data allowed more satellite radiance data to pass the deviation test and get used by the assimilation, which resulted in improved initial driving fields and better simulation in terms of temperature, relative humidity, vertical convection, and cumulative precipitation.

The spatial distribution characteristics of shallow fissures of a landslide in the Wenchuan earthquake area

Shallow fissures, being the main infiltration paths of fluid on the surface of a slope, played an important role in the whole process of a landslide. However, the spatial distribution characteristics of fissures in the slope are difficult to be determined. In this study, we attempted to characterize the variation pattern of slope fissures along depth in the Wenchuan earthquake area in Sichuan Province by combining engineering geological investigation, geomorphologic analysis and geophysical investigation. The geophysical methods that were used in this study include Multichannel Analysis of Surface Wave(MASW), Ground Penetrating Radar(GPR) and Electrical Resistivity Tomography(ERT). The results suggested that geophysical parameters(shear wave velocity, electromagnetic signals attenuation and resistivity) could provide valuable information for the spatial network of shallow fissures. Through the verification by engineering geological survey and geophysical sensitivity analysis, this work highlighted that MASW was the most appropriate technique to delineate the propagation of shallow fissures in a gravel soil slope.

Joint tomographic inversion of first-arrival and reflection traveltimes for recovering 2-D seismic velocity structure with an irregular free surface

Irregular surface flattening,which is based on a boundary conforming grid and the transformation between curvilinear and Cartesian coordinate systems,is a mathematical method that can elegantly handle irregular surfaces,but has been limited to obtaining first arrivals only.By combining a multistage scheme with the fast-sweeping method(FSM,the method to obtain first-arrival traveltime in curvilinear coordinates),the reflected waves from a crustal interface can be traced in a topographic model,in which the reflected wavefront is obtained by reinitializing traveltimes in the interface for upwind branches.A local triangulation is applied to make a connection between velocity and interface nodes.Then a joint inversion of first-arrival and reflection traveltimes for imaging seismic velocity structures in complex terrains is presented.Numerical examples all perform well with different seismic velocity models.The increasing topographic complexity and even use of a high curvature reflector in these models demonstrate the reliability,accuracy and robustness of the new working scheme;checkerboard testing illustrates the method's high resolution.Noise tolerance testing indicates the method's ability to yield practical traveltime tomography.Further development of the multistage scheme will allow other later arrivals to be traced and used in the traveltime inversion.

Review of pre-processing technologies for ice cores

High-resolution ice core records covering long time spans enable reconstruction of the past climatic and environmental conditions allowing the investigation of the earth system's evolution. Preprocessing of ice cores has direct impacts on the data quality control for further analysis since the conventional ice core processing is time-consuming, produces qualitative data, leads to ice mass loss, and leads to risks of potential secondary pollution. However, over the past several decades, preprocessing of ice cores has received less attention than the improvement of ice drilling, the analytical methodology of various indices, and the researches on the climatic and environmental significance of ice core records. Therefore, this papers reviews the development of the processing for ice cores including framework, design as well as materials, analyzes the technical advantages and disadvantages of the different systems. In the past, continuous flowanalysis(CFA) has been successfully applied to process the polar ice cores. However, it is not suitable for ice cores outside polar region because of high level of particles, the memory effect between samples, and the filtration before injection. Ice core processing is a subtle and professional operation due to the fragility of the nonmetallic materials and the random distribution of particles and air bubbles in ice cores, which aggravates uncertainty in the measurements. The future developments of CFA are discussed in preprocessing, memory effect, challenge for brittle ice, coupling with real-time analysis and optimization of CFA in the field. Furthermore, non-polluting cutters with many different configurations could be designed to cut and scrape in multiple directions and to separate inner and outer portions of the core. This system also needs to be coupled with streamlined operation of packaging, coding, and stacking that can be implemented at high resolution and rate, avoiding manual intervention. At the same time, information of the longitudinal sections could be scanned andidentified, and then classified to obtain quantitative data. In addition, irregular ice volume and weight can also be obtained accurately. These improvements are recorded automatically via user-friendly interfaces. These innovations may be applied to other paleomedias with similar features and needs.

Estimations of Land Surface Characteristic Parameters and Turbulent Heat Fluxes over the Tibetan Plateau Based on FY-4A/AGRI Data

Accurate estimates of land surface characteristic parameters and turbulent heat fluxes play an important role in the understanding of land-atmosphere interaction. In this study, Fengyun-4A (FY-4A) Advanced Geostationary Radiation Imager (AGRI) satellite data and the China Land Data Assimilation System (CLDAS) meteorological forcing dataset CLDAS-V2.0 were applied for the retrieval of broadband albedo, land surface temperature (LST), radiation flux components, and turbulent heat fluxes over the Tibetan Plateau (TP). The FY-4A/AGRI and CLDAS-V2.0 data from 12 March 2018 to 30 April 2018 were first used to estimate the hourly turbulent heat fluxes over the TP. The time series data of in-situ measurements from the Tibetan Observation and Research Platform were divided into two halves-one for developing retrieval algorithms for broadband albedo and LST based on FY-4A, and the other for the cross validation. Results show the root-mean-square errors (RMSEs) of the FY-4A retrieved broadband albedo and LST were 0.0309 and 3.85 K, respectively, which verifies the applicability of the retrieval method. The RMSEs of the downwelling/upwelling shortwave radiation flux and downwelling/upwelling longwave radiation flux were 138.87/32.78 W m^(−2) and 51.55/17.92 W m^(−2), respectively, and the RMSEs of net radiation flux, sensible heat flux, and latent heat flux were 58.88 W m^(−2), 82.56 W m^(−2) and 72.46 W m^(−2), respectively. The spatial distributions and diurnal variations of LST and turbulent heat fluxes were further analyzed in detail.