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Examining the effect of ice dynamic changes on subglacial hydrology through modelling of a synthetic Antarctic glacier 通过模拟南极合成冰川考察冰动力变化对冰下水文的影响
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-21 DOI: 10.1017/jog.2023.65
Anna-Mireilla Hayden, Christine F. Dow
Abstract Hydrologic pathways beneath ice sheets and glaciers play an important role in regulating ice flow. Antarctica has experienced, and will continue to experience, changes in ice dynamics and geometry, but the associated changes in subglacial hydrology have received less attention. Here, we use the GlaDS subglacial hydrology model to examine drainage evolution beneath an idealised Antarctic glacier in response to steepening ice surface slopes, accelerating ice velocities and subglacial lake drainages. Ice surface slope changes exerted a dominant influence, redirecting basal water to different outlet locations and substantially increasing channelised discharge crossing the grounding line. Faster ice velocities had comparatively negligible effects. Subglacial lake drainage results indicated that lake refilling times play a key role in drainage system evolution, with lake flux more readily accommodated following shorter refilling times. Our findings are significant for vulnerable Antarctic regions currently experiencing dynamic thinning since subglacial water re-routing could destabilise ice shelves through enhanced sub-shelf melting, potentially hastening irreversible retreat. These changes could also affect subglacial lake activity. We, therefore, emphasise that including a nuanced and complex representation of subglacial hydrology in ice-sheet models could provide critical information on the timing and magnitude of sea-level change contributions from Antarctica.
冰盖和冰川下的水文通道在调节冰流中起着重要作用。南极洲已经经历并将继续经历冰的动力和几何形状的变化,但冰下水文的相关变化受到的关注较少。在这里,我们使用GlaDS冰下水文模型来研究理想南极冰川下的排水演变,以响应冰面斜坡变陡、冰速加速和冰下湖泊排水。冰面坡度的变化发挥了主导作用,将基底水重新定向到不同的出口位置,并大大增加了穿越接地线的渠化流量。相对而言,更快的冰速影响可以忽略不计。冰下湖泊排水结果表明,湖泊填填时间对流域系统演化起关键作用,填填时间越短,湖泊通量越容易被调节。我们的研究结果对目前正在经历动态变薄的脆弱南极地区具有重要意义,因为冰下水的重新输送可能通过加强冰下融化而破坏冰架的稳定,可能加速不可逆转的退缩。这些变化也可能影响冰下湖泊的活动。因此,我们强调,在冰盖模型中加入细致而复杂的冰下水文,可以提供关于南极对海平面变化贡献的时间和幅度的关键信息。
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引用次数: 0
Simulating the processes controlling ice-shelf rift paths using damage mechanics 用损伤力学模拟控制冰架断裂路径的过程
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-21 DOI: 10.1017/jog.2023.71
Alex Huth, Ravindra Duddu, Benjamin Smith, Olga Sergienko
Abstract Rifts are full-thickness fractures that propagate laterally across an ice shelf. They cause ice-shelf weakening and calving of tabular icebergs, and control the initial size of calved icebergs. Here, we present a joint inverse and forward computational modeling framework to capture rifting by combining the vertically integrated momentum balance and anisotropic continuum damage mechanics formulations. We incorporate rift–flank boundary processes to investigate how the rift path is influenced by the pressure on rift–flank walls from seawater, contact between flanks, and ice mélange that may also transmit stress between flanks. To illustrate the viability of the framework, we simulate the final 2 years of rift propagation associated with the calving of tabular iceberg A68 in 2017. We find that the rift path can change with varying ice mélange conditions and the extent of contact between rift flanks. Combinations of parameters associated with slower rift widening rates yield simulated rift paths that best match observations. Our modeling framework lays the foundation for robust simulation of rifting and tabular calving processes, which can enable future studies on ice-sheet–climate interactions, and the effects of ice-shelf buttressing on land ice flow.
裂缝是沿冰架横向传播的全层裂缝。它们造成冰架的削弱和板状冰山的崩解,并控制崩解冰山的初始大小。在这里,我们提出了一个联合的逆正演计算模型框架,通过结合垂直积分动量平衡和各向异性连续损伤力学公式来捕捉裂谷。我们结合裂谷-翼面边界过程来研究裂谷路径如何受到来自海水的裂谷-翼面壁面压力、侧翼之间的接触以及可能在侧翼之间传递应力的冰的影响。为了说明该框架的可行性,我们模拟了与2017年A68平板冰山崩解相关的最后2年裂缝传播。研究发现,裂谷路径会随着冰缘条件和裂谷两侧接触程度的变化而变化。与较慢的裂谷扩大速率相关的参数组合产生了与观测结果最匹配的模拟裂谷路径。我们的建模框架为裂谷和板状崩解过程的稳健模拟奠定了基础,这可以为未来研究冰盖-气候相互作用以及冰架支撑对陆地冰流的影响奠定基础。
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引用次数: 0
Ground penetrating radar in temperate ice: englacial water inclusions as limiting factor for data interpretation 温带冰的探地雷达:冰川水包裹体作为数据解释的限制因素
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-21 DOI: 10.1017/jog.2023.68
Christophe Ogier, Dirk-Jan van Manen, Hansruedi Maurer, Ludovic Räss, Marian Hertrich, Andreas Bauder, Daniel Farinotti
Abstract Ground penetrating radar (GPR) has been extensively used in glaciology to infer glacier's ice thickness, liquid water content, water drainage pathways, and other properties. The interpretation of such GPR data is not always straightforward and for temperate glaciers, the signal is often affected by strong scattering and attenuation. It has often been suggested that such effects originate from englacial water inclusions, since water and ice have a large contrast in their di-electric permittivity. To investigate such effects quantitatively, we perform an extensive numerical modeling study of GPR signals. By exploring how different liquid water contents (LWC) and water-inclusions size affect the GPR signal, we show that their effects are much larger than the potential presence of a wet snowpack or a heterogeneous distribution of ice permittivity. In particularly, we show that the presence of such water inclusions is a necessary and sufficient condition for reproducing the typical characteristics of GPR data acquired in the field. Further, we find that for 25 MHz GPR antennas, a bulk LWC $gtrsim$ 0.2%, associated with decimeters-scale water inclusions already limits bedrock detectability for ice thicknesses $gtrsim 100$ m. Since these values are typical for Alpine glaciers, they clarify why the quality of GPR data is often poor in such environments.
摘要探地雷达(GPR)在冰川学中得到了广泛的应用,可以推断冰川的冰厚、液态水含量、排水路径等性质。这种探地雷达数据的解释并不总是直截了当的,对于温带冰川,信号经常受到强烈散射和衰减的影响。由于水和冰的介电常数有很大的差别,因此经常有人提出这种效应是由冰川的水包裹体引起的。为了定量研究这种影响,我们对探地雷达信号进行了广泛的数值模拟研究。通过探索不同液态水含量(LWC)和水包裹体大小对探地雷达信号的影响,我们发现它们的影响远远大于可能存在的湿积雪或冰介电常数的非均匀分布。特别是,我们表明,这种水包裹体的存在是再现在现场获得的GPR数据的典型特征的必要和充分条件。此外,我们发现,对于25 MHz GPR天线,大量LWC为0.2%,与分米尺度的水夹杂物相关,已经限制了基岩对冰厚度100 m的可探测性。由于这些值对于高山冰川来说是典型的,它们阐明了为什么GPR数据的质量在这种环境中往往很差。
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引用次数: 0
A novel laser melting sampler for discrete, sub-centimeter depth-resolved analyses of stable water isotopes in ice cores 一种新型激光熔化采样器,用于冰芯中稳定水同位素的离散,亚厘米深度分辨分析
3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-19 DOI: 10.1017/jog.2023.52
Yuko Motizuki, Yoichi Nakai, Kazuya Takahashi, Junya Hirose, Yu Vin Sahoo, Masaki Yumoto, Masayuki Maruyama, Michio Sakashita, Kiwamu Kase, Satoshi Wada, Hideaki Motoyama, Yasushige Yano
Abstract We developed a novel laser melting sampler (LMS) for ice cores to measure the stable water isotope ratios (δ 18 O and δD) as temperature proxies at sub-centimeter depth resolutions. In this LMS system, a 2 mm diameter movable evacuation nozzle holds an optical fiber through which a laser beam irradiates the ice core. The movable nozzle intrudes into the ice core, the laser radiation meanwhile melts the ice cylindrically, and the meltwater is pumped away simultaneously through the same nozzle and transferred to a vial for analysis. To avoid isotopic fractionation of the ice through vaporization, the laser power is adjusted to ensure that the temperature of the meltwater is always kept well below its boiling point. A segment of a Dome Fuji shallow ice core (Antarctica), using the LMS, was then demonstrated to have been discretely sampled with a depth resolution as small as 3 mm: subsequent analysis of δ 18 O, δD, and deuterium excess ( d ) was consistent with results obtained by hand segmentation within measurement uncertainties. With system software to control sampling resolution, the LMS will enable us to identify temperature variations that may be detectable only at sub-centimeter resolutions in ice cores.
摘要研制了一种新型的冰芯激光熔化采样器(LMS),用于测量亚厘米深度分辨率下稳定水同位素(δ 18o和δ d)的温度。在这个LMS系统中,一个直径2毫米的可移动疏散喷嘴容纳一根光纤,激光束通过该光纤照射冰芯。移动喷嘴侵入冰芯,激光辐射同时使冰圆柱状融化,融化水通过同一喷嘴同时被抽走并转移到小瓶中进行分析。为了避免冰在蒸发过程中产生同位素分馏,需要调整激光功率,以确保融水的温度始终保持在远低于沸点的水平。随后,使用LMS对Dome Fuji(南极洲)浅层冰芯的一段进行了离散采样,深度分辨率小至3毫米:随后对δ 18o、δ d和氘过量(d)的分析与测量不确定度内手工分割得到的结果一致。通过控制采样分辨率的系统软件,LMS将使我们能够识别只有在冰芯的亚厘米分辨率下才能检测到的温度变化。
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引用次数: 0
Estimating the elastic modulus of landfast ice from wave observations 由波浪观测估计陆面冰的弹性模量
IF 3.4 3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-06 DOI: 10.1017/jog.2023.63
J. Voermans, J. Rabault, A. Marchenko, T. Nose, T. Waseda, A. Babanin
Progress in our understanding of wave–ice interactions is currently hindered by the lack of in situ observations and information of sea-ice properties, including the elastic modulus. Here, we estimate the effective elastic modulus of sea ice using observations of waves in ice through the deployment of three open-source geophone recorders on landfast sea ice. From observations of low-frequency dispersive waves, we obtain an estimate of the effective elastic modulus in the range of 0.4–0.7 GPa. This is lower than the purely elastic modulus of the ice estimated at 1 GPa as derived from in situ beam experiments. Importantly, our experimental observation is significantly lower than the default value currently in use in wave models. While our estimate is not representative for all sea ice, it does indicate that considerably more measurements are required to provide confidence in the development of parameterizations for this complex sea-ice property for wave models.
目前,由于缺乏海冰特性(包括弹性模量)的现场观测和信息,我们对波浪-冰相互作用的理解进展受到阻碍。在这里,我们通过在登陆海冰上部署三个开源地震检波器记录器,利用冰中波浪的观测来估计海冰的有效弹性模量。根据低频色散波的观测,我们获得了0.4–0.7 GPa范围内的有效弹性模量的估计值。这低于根据现场梁实验估计的1GPa的冰的纯弹性模量。重要的是,我们的实验观测值明显低于目前波浪模型中使用的默认值。虽然我们的估计并不代表所有海冰,但它确实表明,需要更多的测量来为波浪模型的这种复杂海冰特性的参数化发展提供信心。
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引用次数: 1
Quantified mass loss of the Laohugou ice core and its precipitation signal during 1961–2005 at high elevation in the northeastern Tibetan Plateau 青藏高原东北部高海拔老虎沟冰芯1961-2005年量化质量损失及其降水信号
IF 3.4 3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-06 DOI: 10.1017/jog.2023.51
W. Du, Shichang Kang, Ji-zu Chen, Weijun Sun, Xiang Qin, Zhenming Ji, Wenxuan Sun, Yanan Qiu
Ice records provide a qualitative rather than a quantitative indication of the trend of climate change. Using the bulk aerodynamic method and degree day model, this study quantified ice mass loss attributable to sublimation/evaporation (S/E) and meltwater on the basis of integrated observations (1960–2006) of glacier-related and atmospheric variables in the northeastern Tibetan Plateau. During 1961–2005, the average annual mass loss in the ice core was 95.33 ± 20.56 mm w.e. (minimum: 78.97 mm w.e. in 1967, maximum: 146.67 mm w.e. in 2001), while the average ratio of the revised annual ice accumulation was 21.2 ± 7.7% (minimum: 11.0% in 1992, maximum 44.8% in 2000). A quantitative formula expressing the relationship between S/E and air temperature at the monthly scale was established, which could be extended to estimation of S/E changes of other glaciers in other regions. The elevation effect on alpine precipitation determined using revised ice accumulation and instrumental data was found remarkable. This work established a method for quantitative assessment of the temporal variation in ice core mass loss, and advanced the reconstruction of long-term precipitation at high elevations. Importantly, the formula established for reconstruction of S/E from temperature time series data could be used in other regions.
冰记录提供了气候变化趋势的定性而非定量指示。本研究采用整体空气动力学方法和度日模型,在对青藏高原东北部冰川相关和大气变量的综合观测(1960-2006)的基础上,量化了升华/蒸发(S/E)和融水造成的冰质量损失。1961年至2005年间,冰芯的平均年质量损失为95.33±20.56毫米(1967年最小:78.97毫米,2001年最大:146.67毫米),而修正后的年积冰平均比例为21.2±7.7%(1992年最小:11.0%,2000年最大:44.8%)。建立了一个表示月尺度S/E与气温关系的定量公式,该公式可推广到其他地区其他冰川S/E变化的估计。使用修正的冰积累和仪器数据确定的海拔对高山降水的影响是显著的。这项工作建立了一种定量评估冰芯质量损失时间变化的方法,并提出了高海拔地区长期降水的重建方法。重要的是,根据温度-时间序列数据建立的S/E重建公式可以用于其他区域。
{"title":"Quantified mass loss of the Laohugou ice core and its precipitation signal during 1961–2005 at high elevation in the northeastern Tibetan Plateau","authors":"W. Du, Shichang Kang, Ji-zu Chen, Weijun Sun, Xiang Qin, Zhenming Ji, Wenxuan Sun, Yanan Qiu","doi":"10.1017/jog.2023.51","DOIUrl":"https://doi.org/10.1017/jog.2023.51","url":null,"abstract":"\u0000 Ice records provide a qualitative rather than a quantitative indication of the trend of climate change. Using the bulk aerodynamic method and degree day model, this study quantified ice mass loss attributable to sublimation/evaporation (S/E) and meltwater on the basis of integrated observations (1960–2006) of glacier-related and atmospheric variables in the northeastern Tibetan Plateau. During 1961–2005, the average annual mass loss in the ice core was 95.33 ± 20.56 mm w.e. (minimum: 78.97 mm w.e. in 1967, maximum: 146.67 mm w.e. in 2001), while the average ratio of the revised annual ice accumulation was 21.2 ± 7.7% (minimum: 11.0% in 1992, maximum 44.8% in 2000). A quantitative formula expressing the relationship between S/E and air temperature at the monthly scale was established, which could be extended to estimation of S/E changes of other glaciers in other regions. The elevation effect on alpine precipitation determined using revised ice accumulation and instrumental data was found remarkable. This work established a method for quantitative assessment of the temporal variation in ice core mass loss, and advanced the reconstruction of long-term precipitation at high elevations. Importantly, the formula established for reconstruction of S/E from temperature time series data could be used in other regions.","PeriodicalId":15981,"journal":{"name":"Journal of Glaciology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43247250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Detection and characterization of discontinuous motion on Thompson Glacier, Canadian High Arctic, using synthetic aperture radar speckle tracking and ice-flow modeling 利用合成孔径雷达散斑跟踪和冰流建模探测和表征加拿大北极高地汤普森冰川的不连续运动
IF 3.4 3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-06 DOI: 10.1017/jog.2023.67
Giovanni Corti, B. Rabus, G. Flowers
We investigate unusual discontinuous glacier motion on Thompson Glacier, Umingmat Nunaat, Arctic Canada, using synthetic aperture radar (SAR) images and ice-flow modeling. A novel intensity-rescaling scheme is developed to reduce errors in high-resolution speckle tracking, resulting in a ~25% improvement in accuracy. Interferometric SAR (InSAR) and speckle tracking using high resolution RADARSAT-2 data indicate velocity discontinuities of up to 1 cm d−1 across deep and longitudinally extensive supraglacial channels on Thompson Glacier. We use a cross-sectional finite-element ice-flow model to determine the conditions under which velocity discontinuities of the observed magnitude and signature are possible. The modeling suggests that discontinuous motion across (long and straight) supraglacial channels can occur without ice fracture and under a wide variety of glacier thermal structures, including in fully temperate glaciers. Despite the wide range of conditions conducive to discontinuous motion, the form we observe requires that the associated channels be deep, longitudinally extensive and located in regions of lateral shearing. We speculate that these combined conditions are rare except on polythermal glaciers, where drainage features such as moulins are comparatively scarce and lower deformation rates allow channels to incise consistently and persist over many years.
我们使用合成孔径雷达(SAR)图像和冰流建模,研究了加拿大北极乌明马特-努纳特汤普森冰川上不寻常的不连续冰川运动。开发了一种新的强度重新缩放方案,以减少高分辨率散斑跟踪中的误差,从而使精度提高约25%。干涉SAR(InSAR)和使用高分辨率RADARSAT-2数据的散斑跟踪表明,汤普森冰川上深层和纵向扩展的冰上通道的速度不连续性高达1 cm d−1。我们使用截面有限元冰流模型来确定观测到的幅度和特征的速度不连续性可能存在的条件。该模型表明,在没有冰破裂的情况下,在各种各样的冰川热结构下,包括在全温带冰川中,可以发生跨越(长而直)冰上通道的不连续运动。尽管有利于不连续运动的广泛条件,但我们观察到的形式要求相关通道是深的、纵向延伸的,并且位于横向剪切区域。我们推测,除了多热冰川外,这些综合条件很少见,多热冰川的排水特征(如丘林)相对较少,较低的变形率使通道能够持续切割并持续多年。
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引用次数: 0
Fifty years of instrumental surface mass balance observations at Vostok Station, central Antarctica 南极中部沃斯托克站50年地表物质平衡仪器观测
IF 3.4 3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-09-04 DOI: 10.1017/jog.2023.53
A. Ekaykin, V. Lipenkov, N. Tebenkova
We present the surface mass balance (SMB) dataset from Vostok Station's accumulation stake farms which provide the longest instrumental record of its kind obtained with a uniform technique in central Antarctica over the last 53 years. The snow build-up values at individual stakes demonstrate a strong random scatter related to the interaction of wind-driven snow with snow micro-relief. Because of this depositional noise, the signal-to-noise ratio (SNR) in individual SMB time series derived at single points (from stakes, snow pits or firn cores) is as low as 0.045. Averaging the data over the whole stake farm increases the SNR to 2.3 and thus allows us to investigate reliably the climatic variability of the SMB. Since 1970, the average snow accumulation rate at Vostok has been 22.5 ± 1.3 kg m−2 yr−1. Our data suggest an overall increase of the SMB during the observation period accompanied by a significant decadal variability. The main driver of this variability is local air temperature with an SMB temperature sensitivity of 2.4 ± 0.2 kg m−2 yr−1 K−1 (11 ± 2% K−1). A covariation between the Vostok SMB and the Southern Oscillation Index is also observed.
我们提供了来自Vostok站积累场场的地表质量平衡(SMB)数据集,该数据集提供了过去53年来在南极洲中部使用统一技术获得的最长仪器记录。单个桩的雪积值表现出与风驱动雪和雪微地形相互作用有关的强随机散射。由于这种沉积噪声,单点(来自木桩、雪坑或铁芯)的单个SMB时间序列的信噪比(SNR)低至0.045。对整个桩场的数据进行平均,将信噪比提高到2.3,从而使我们能够可靠地研究SMB的气候变异性。自1970年以来,Vostok的平均积雪率为22.5±1.3 kg m−2 yr−1。我们的数据表明,在观测期间,SMB总体增加,并伴有显著的年代际变化。这种变化的主要驱动因素是当地气温,SMB温度敏感性为2.4±0.2 kg m−2 yr−1 K−1(11±2% K−1)。在Vostok SMB和南方涛动指数之间也观察到协变。
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引用次数: 1
Bayesian parameter estimation in glacier mass-balance modelling using observations with distinct temporal resolutions and uncertainties 利用不同时间分辨率和不确定性观测资料进行冰川质量平衡模拟中的贝叶斯参数估计
IF 3.4 3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-08-31 DOI: 10.1017/jog.2023.62
Kamilla H. Sjursen, T. Dunse, Antoine Tambue, T. Schuler, L. Andreassen
Empirical glacier mass-balance models are commonly used in assessments of glacier and runoff evolution. Recent satellite-borne geodetic mass-balance observations of global coverage facilitate large-scale model calibration that previously relied on sparse in situ observations of glacier mass change. Geodetic observations constitute temporally aggregated mass-balance signals with significant uncertainty, raising questions about the role of observations with different temporal resolutions and uncertainties in constraining model parameters. We employ a Bayesian approach and demonstrate the sensitivity of parameter values to commonly used mass-balance observations of seasonal, annual and decadal resolution with uncertainties characteristic to in situ and satellite-borne observations. For glaciers along a continentality gradient in Norway, the use of annual mass balances results in around 20% lower magnitude of modelled ablation and accumulation (1960–2020), compared to employing seasonal balances. Decadal mass balance also underestimates magnitudes of ablation and accumulation, but parameter values are strongly influenced by the prior distribution. The datasets yield similar estimates of annual mass balance with different margins of uncertainty. Decadal observations are afflicted with considerable uncertainty in mass-balance sensitivity due to high parameter uncertainty. Our results highlight the importance of seasonal observations when model applications require accurate magnitudes of ablation, e.g. to estimate meltwater runoff.
经验冰川质量平衡模型通常用于评估冰川和径流的演变。最近对全球覆盖范围的卫星测地质量平衡观测促进了大规模的模型校准,以前这种校准依赖于冰川质量变化的稀疏原位观测。大地测量观测构成了具有显著不确定性的时间聚合质量平衡信号,这引发了人们对具有不同时间分辨率和不确定性的观测在约束模型参数方面的作用的质疑。我们采用贝叶斯方法,证明了参数值对季节、年度和十年分辨率的常用质量平衡观测的敏感性,以及对现场和星载观测的不确定性特征。对于挪威大陆性梯度沿线的冰川,与使用季节平衡相比,使用年度质量平衡可使模拟消融和堆积的幅度(1960-2020年)降低约20%。十年质量平衡也低估了消融和积累的幅度,但参数值受到先验分布的强烈影响。数据集产生了具有不同不确定性的年度质量平衡的类似估计。由于高参数不确定性,十年观测在质量平衡灵敏度方面存在相当大的不确定性。我们的研究结果强调了季节性观测的重要性,当模型应用需要精确的消融幅度时,例如估计融水径流。
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引用次数: 0
Surge-type glaciers in Kalaallit Nunaat (Greenland): distribution, temporal patterns and climatic controls Kalaallit Nunaat(格陵兰)的涌浪型冰川:分布、时间模式和气候控制
IF 3.4 3区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2023-08-31 DOI: 10.1017/jog.2023.61
H. Lovell, J. Carrivick, O. King, J. Sutherland, J. Yde, C. M. Boston, Jakub Małecki
We present the first systematic inventory of surge-type glaciers for the whole of Greenland compiled from published datasets and multitemporal satellite images and digital elevation models. The inventory allows us to define the spatial and climatic distribution of surge-type glaciers and to analyse the timing of surges from 1985 to 2019. We identified 274 surge-type glaciers, an increase of 37% compared to previous work. Mapping surge-type glacier distribution by temperature and precipitation variables derived from ERA5-Land reanalysis data shows that the west and east clusters occur in well-defined climatic envelopes. Analysis of the timing of surge active phases during the periods ~1985 to 2000 (T1) and ~2000 to 2019 (T2) suggests that overall surge activity is similar in T1 and T2, but there appears to be a reduction in surging in the west cluster in T2. Our climate analysis shows a coincident increase in mean annual and mean winter air temperature between T1 and T2. We suggest that as glaciers thin under current warming, some surge-type glaciers in the west cluster may be being prevented from surging due to (1) their inability to build-up sufficient mass and (2) a switch from a polythermal to a largely cold-based thermal regime.
我们根据已发表的数据集、多时相卫星图像和数字高程模型编制了整个格陵兰岛涌浪型冰川的第一个系统清单。该清单使我们能够确定涌浪型冰川的空间和气候分布,并分析1985年至2019年涌浪的时间。我们确定了274个激流型冰川,比以前的工作增加了37%。利用ERA5-Land再分析数据得出的温度和降水变量绘制激流型冰川分布图,表明西部和东部冰川群出现在明确的气候包络中。对~1985 ~2000年(T1)和~2000 ~ 2019年(T2)期间浪涌活动期时间的分析表明,在T1和T2期间,总体浪涌活动相似,但在T2期间,西部集群的浪涌似乎有所减少。我们的气候分析显示,在T1和T2之间,年平均气温和冬季平均气温同时上升。我们认为,在当前变暖的情况下,随着冰川变薄,西部冰川群中的一些涌浪型冰川可能会因以下原因而无法涌浪:1)它们无法积累足够的质量;2)从多热状态转变为主要以冷为基础的热状态。
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引用次数: 0
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Journal of Glaciology
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