@inproceedings{11880,
  abstract     = {Given a directed graph and a source vertex, the fully dynamic single-source reachability problem is to maintain the set of vertices that are reachable from the given vertex, subject to edge deletions and insertions. It is one of the most fundamental problems on graphs and appears directly or indirectly in many and varied applications. While there has been theoretical work on this problem, showing both linear conditional lower bounds for the fully dynamic problem and insertions-only and deletions-only upper bounds beating these conditional lower bounds, there has been no experimental study that compares the performance of fully dynamic reachability algorithms in practice. Previous experimental studies in this area concentrated only on the more general all-pairs reachability or transitive closure problem and did not use real-world dynamic graphs.

In this paper, we bridge this gap by empirically studying an extensive set of algorithms for the single-source reachability problem in the fully dynamic setting. In particular, we design several fully dynamic variants of well-known approaches to obtain and maintain reachability information with respect to a distinguished source. Moreover, we extend the existing insertions-only or deletions-only upper bounds into fully dynamic algorithms. Even though the worst-case time per operation of all the fully dynamic algorithms we evaluate is at least linear in the number of edges in the graph (as is to be expected given the conditional lower bounds) we show in our extensive experimental evaluation that their performance differs greatly, both on generated as well as on real-world instances.},
  author       = {Hanauer, Kathrin and Henzinger, Monika H and Schulz, Christian},
  booktitle    = {2020 Symposium on Algorithm Engineering and Experiments},
  location     = {Salt Lake City, UT, United States},
  pages        = {106--119},
  publisher    = {Society for Industrial and Applied Mathematics},
  title        = {{Fully dynamic single-source reachability in practice: An experimental study}},
  doi          = {10.1137/1.9781611976007.9},
  year         = {2020},
}

@inproceedings{11881,
  abstract     = {We introduce the fastest known exact algorithm for the multiterminal cut problem with k terminals. In particular, we engineer existing as well as new data reduction rules. We use the rules within a branch-and-reduce framework and to boost the performance of an ILP formulation. Our algorithms achieve improvements in running time of up to multiple orders of magnitudes over the ILP formulation without data reductions, which has been the de facto standard used by practitioners. This allows us to solve instances to optimality that are significantly larger than was previously possible.},
  author       = {Henzinger, Monika H and Noe, Alexander and Schulz, Christian},
  booktitle    = {2020 Symposium on Algorithm Engineering and Experiments},
  location     = {Salt Lake City, UT, United States},
  pages        = {42--55},
  publisher    = {Society for Industrial and Applied Mathematics},
  title        = {{Shared-memory branch-and-reduce for multiterminal cuts}},
  doi          = {10.1137/1.9781611976007.4},
  year         = {2020},
}

@article{11889,
  abstract     = {We study the problem of computing a minimum cut in a simple, undirected graph and give a deterministic 𝑂(𝑚log2𝑛loglog2𝑛) time algorithm. This improves on both the best previously known deterministic running time of 𝑂(𝑚log12𝑛) (Kawarabayashi and Thorup [J. ACM, 66 (2018), 4]) and the best previously known randomized running time of 𝑂(𝑚log3𝑛) (Karger [J. ACM, 47 (2000), pp. 46--76]) for this problem, though Karger's algorithm can be further applied to weighted graphs. Moreover, our result extends to balanced directed graphs, where the balance of a directed graph captures how close the graph is to being Eulerian. Our approach is using the Kawarabayashi and Thorup graph compression technique, which repeatedly finds low conductance cuts. To find these cuts they use a diffusion-based local algorithm. We use instead a flow-based local algorithm and suitably adjust their framework to work with our flow-based subroutine. Both flow- and diffusion-based methods have a long history of being applied to finding low conductance cuts. Diffusion algorithms have several variants that are naturally local, while it is more complicated to make flow methods local. Some prior work has proven nice properties for local flow-based algorithms with respect to improving or cleaning up low conductance cuts. Our flow subroutine, however, is the first that both is local and produces low conductance cuts. Thus, it may be of independent interest.},
  author       = {Henzinger, Monika H and Rao, Satish and Wang, Di},
  issn         = {1095-7111},
  journal      = {SIAM Journal on Computing},
  number       = {1},
  pages        = {1--36},
  publisher    = {Society for Industrial & Applied Mathematics},
  title        = {{Local flow partitioning for faster edge connectivity}},
  doi          = {10.1137/18m1180335},
  volume       = {49},
  year         = {2020},
}

@article{11894,
  abstract     = {Graph sparsification aims at compressing large graphs into smaller ones while preserving important characteristics of the input graph. In this work we study vertex sparsifiers, i.e., sparsifiers whose goal is to reduce the number of vertices. We focus on the following notions: (1) Given a digraph 𝐺=(𝑉,𝐸) and terminal vertices 𝐾⊂𝑉 with |𝐾|=𝑘, a (vertex) reachability sparsifier of 𝐺 is a digraph 𝐻=(𝑉𝐻,𝐸𝐻), 𝐾⊂𝑉𝐻 that preserves all reachability information among terminal pairs. Let |𝑉𝐻| denote the size of 𝐻. In this work we introduce the notion of reachability-preserving minors (RPMs), i.e., we require 𝐻 to be a minor of 𝐺. We show any directed graph 𝐺 admits an RPM 𝐻 of size 𝑂(𝑘3), and if 𝐺 is planar, then the size of 𝐻 improves to 𝑂(𝑘2log𝑘). We complement our upper bound by showing that there exists an infinite family of grids such that any RPM must have Ω(𝑘2) vertices. (2) Given a weighted undirected graph 𝐺=(𝑉,𝐸) and terminal vertices 𝐾 with |𝐾|=𝑘, an exact (vertex) cut sparsifier of 𝐺 is a graph 𝐻 with 𝐾⊂𝑉𝐻 that preserves the value of minimum cuts separating any bipartition of 𝐾. We show that planar graphs with all the 𝑘 terminals lying on the same face admit exact cut sparsifiers of size 𝑂(𝑘2) that are also planar. Our result extends to flow and distance sparsifiers. It improves the previous best-known bound of 𝑂(𝑘222𝑘) for cut and flow sparsifiers by an exponential factor and matches an Ω(𝑘2) lower-bound for this class of graphs.},
  author       = {Goranci, Gramoz and Henzinger, Monika H and Peng, Pan},
  issn         = {1095-7146},
  journal      = {SIAM Journal on Discrete Mathematics},
  number       = {1},
  pages        = {130--162},
  publisher    = {Society for Industrial & Applied Mathematics},
  title        = {{Improved guarantees for vertex sparsification in planar graphs}},
  doi          = {10.1137/17m1163153},
  volume       = {34},
  year         = {2020},
}

@article{11954,
  abstract     = {The combination of nickel and photocatalysis has unlocked a variety of cross-couplings. These protocols rely on a few photocatalysts that can only convert a small portion of visible light (<500 nm) into chemical energy. The high-energy photons that excite the photocatalyst can result in unwanted side reactions. Dyes that absorb a much broader spectrum of light are not applicable because of their short-lived singlet excited states. Here, we describe a self-assembling catalyst system that overcomes this limitation. Immobilization of a nickel catalyst on dye-sensitized titanium dioxide results in a material that catalyzes carbon–heteroatom and carbon–carbon bond formations. The modular approach of dye-sensitized metallaphotocatalysts accesses the entire visible light spectrum and allows tackling selectivity issues resulting from low wavelengths strategically. The concept overcomes current limitations of metallaphotocatalysis by unlocking the potential of dyes that were previously unsuitable.},
  author       = {Reischauer, Susanne and Strauss, Volker and Pieber, Bartholomäus},
  issn         = {2155-5435},
  journal      = {ACS Catalysis},
  number       = {22},
  pages        = {13269–13274},
  publisher    = {American Chemical Society},
  title        = {{Modular, self-assembling metallaphotocatalyst for cross-couplings using the full visible-light spectrum}},
  doi          = {10.1021/acscatal.0c03950},
  volume       = {10},
  year         = {2020},
}

@article{11966,
  abstract     = {The front cover artwork is provided by the group of Dr. Bartholomäus Pieber at the Max Planck Institute of Colloids and Interfaces (Germany). The image symbolizes the activation of a heterogeneous photocatalyst by visible light and its application for organic synthesis. Read the full text of the Review at 10.1002/cptc.202000014.},
  author       = {Gisbertz, Sebastian and Pieber, Bartholomäus},
  issn         = {2367-0932},
  journal      = {ChemPhotoChem},
  number       = {7},
  pages        = {454--454},
  publisher    = {Wiley},
  title        = {{Heterogeneous photocatalysis in organic synthesis}},
  doi          = {10.1002/cptc.202000137},
  volume       = {4},
  year         = {2020},
}

@article{11969,
  abstract     = {Photochemistry enables new synthetic means to form carbon–heteroatom bonds. Photocatalysts can catalyze carbon–heteroatom cross-couplings by electron or energy transfer either alone or in combination with a second catalyst. Photocatalyst-free methods are possible using photolabile substrates or by generating photoactive electron donor-acceptor complexes. This review summarizes and discusses the strategies used in light-mediated carbon–heteroatom bond formations based on the proposed mechanisms.},
  author       = {Cavedon, Cristian and Seeberger, Peter H. and Pieber, Bartholomäus},
  issn         = {1099-0690},
  journal      = {European Journal of Organic Chemistry},
  number       = {10},
  pages        = {1379--1392},
  publisher    = {Wiley},
  title        = {{Photochemical strategies for carbon–heteroatom bond formation}},
  doi          = {10.1002/ejoc.201901173},
  volume       = {2020},
  year         = {2020},
}

@article{11978,
  abstract     = {Dual photocatalysis and nickel catalysis can effect cross-coupling under mild conditions, but little is known about the in situ kinetics of this class of reactions. We report a comprehensive kinetic examination of a model carboxylate O-arylation, comparing a state-of-the-art homogeneous photocatalyst (Ir(ppy)3) with a competitive heterogeneous photocatalyst (graphitic carbon nitride). Experimental conditions were adjusted such that the nickel catalytic cycle is saturated with excited photocatalyst. This approach was designed to remove the role of the photocatalyst, by which only the intrinsic behaviors of the nickel catalytic cycles are observed. The two reactions did not display identical kinetics. Ir(ppy)3 deactivates the nickel catalytic cycle and creates more dehalogenated side product. Kinetic data for the reaction using Ir(ppy)3 supports a turnover-limiting reductive elimination. Graphitic carbon nitride gave higher selectivity, even at high photocatalyst-to-nickel ratios. The heterogeneous reaction also showed a rate dependence on aryl halide, indicating that oxidative addition plays a role in rate determination. The results argue against the current mechanistic hypothesis, which states that the photocatalyst is only involved to trigger reductive elimination.},
  author       = {Malik, Jamal A. and Madani, Amiera and Pieber, Bartholomäus and Seeberger, Peter H.},
  issn         = {1520-5126},
  journal      = {Journal of the American Chemical Society},
  number       = {25},
  pages        = {11042--11049},
  publisher    = {American Chemical Society},
  title        = {{Evidence for photocatalyst involvement in oxidative additions of nickel-catalyzed carboxylate O-arylations}},
  doi          = {10.1021/jacs.0c02848},
  volume       = {142},
  year         = {2020},
}

@article{11979,
  abstract     = {Dual photoredox/nickel-catalysed C–N cross-couplings suffer from low yields for electron-rich aryl halides. The formation of catalytically inactive nickel-black is responsible for this limitation and causes severe reproducibility issues. Here, we demonstrate that catalyst deactivation can be avoided by using a carbon nitride photocatalyst. The broad absorption of the heterogeneous photocatalyst enables wavelength-dependent control of the rate of reductive elimination to prevent nickel-black formation during the coupling of cyclic, secondary amines and aryl halides. A second approach, which is applicable to a broader set of electron-rich aryl halides, is to run the reactions at high concentrations to increase the rate of oxidative addition. Less nucleophilic, primary amines can be coupled with electron-rich aryl halides by stabilizing low-valent nickel intermediates with a suitable additive. The developed protocols enable reproducible, selective C–N cross-couplings of electron-rich aryl bromides and can also be applied for electron-poor aryl chlorides.},
  author       = {Gisbertz, Sebastian and Reischauer, Susanne and Pieber, Bartholomäus},
  issn         = {2520-1158},
  journal      = {Nature Catalysis},
  number       = {8},
  pages        = {611--620},
  publisher    = {Springer Nature},
  title        = {{Overcoming limitations in dual photoredox/nickel-catalysed C–N cross-couplings due to catalyst deactivation}},
  doi          = {10.1038/s41929-020-0473-6},
  volume       = {3},
  year         = {2020},
}

@article{11980,
  abstract     = {Small organic radicals are ubiquitous intermediates in photocatalysis and are used in organic synthesis to install functional groups and to tune electronic properties and pharmacokinetic parameters of the final molecule. Development of new methods to generate small organic radicals with added functionality can further extend the utility of photocatalysis for synthetic needs. Herein, we present a method to generate dichloromethyl radicals from chloroform using a heterogeneous potassium poly(heptazine imide) (K-PHI) photocatalyst under visible light irradiation for C1-extension of the enone backbone. The method is applied on 15 enones, with γ,γ-dichloroketones yields of 18–89%. Due to negative zeta-potential (−40 mV) and small particle size (100 nm) K-PHI suspension is used in quasi-homogeneous flow-photoreactor increasing the productivity by 19 times compared to the batch approach. The resulting γ,γ-dichloroketones, are used as bifunctional building blocks to access value-added organic compounds such as substituted furans and pyrroles.},
  author       = {Mazzanti, Stefano and Kurpil, Bogdan and Pieber, Bartholomäus and Antonietti, Markus and Savateev, Aleksandr},
  issn         = {2041-1723},
  journal      = {Nature Communications},
  publisher    = {Springer Nature},
  title        = {{Dichloromethylation of enones by carbon nitride photocatalysis}},
  doi          = {10.1038/s41467-020-15131-0},
  volume       = {11},
  year         = {2020},
}

@article{11986,
  abstract     = {Carbon nitride materials have emerged as an efficient and sustainable class of heterogeneous photocatalysts, particularly when paired with nickel in dual catalytic cross-coupling reactions. Performing these transformations on larger scales using a continuous process is difficult due to the problems associated with handling solids in flow. By combining an oscillatory pump with a microstructured plug flow photoreactor, a stable suspension of the photocatalyst can be maintained, circumventing clogging of the reactor channels. Through careful tuning of the oscillator properties, the residence time distribution (RTD) was optimized, whilst maintaining a stable catalyst suspension. Short residence times (20 min) were achieved using optimized conditions and the recyclability of the photocatalyst was demonstrated over 10 cycles with no loss of activity. During a stable 4.5 hour scale-out demonstration, the model substrate could be isolated on 12 g scale (90% yield, 2.67 g h−1). Moreover, the method was applied for the gram scale synthesis of an intermediate of the active pharmaceutical ingredient tetracaine.},
  author       = {Rosso, Cristian and Gisbertz, Sebastian and Williams, Jason D. and Gemoets, Hannes P. L. and Debrouwer, Wouter and Pieber, Bartholomäus and Kappe, C. Oliver},
  issn         = {2058-9883},
  journal      = {Reaction Chemistry and Engineering},
  number       = {3},
  pages        = {597--604},
  publisher    = {Royal Society of Chemistry},
  title        = {{An oscillatory plug flow photoreactor facilitates semi-heterogeneous dual nickel/carbon nitride photocatalytic C–N couplings}},
  doi          = {10.1039/d0re00036a},
  volume       = {5},
  year         = {2020},
}

@article{12188,
  abstract     = {Molecular mechanisms enabling the switching and maintenance of epigenetic states are not fully understood. Distinct histone modifications are often associated with ON/OFF epigenetic states, but how these states are stably maintained through DNA replication, yet in certain situations switch from one to another remains unclear. Here, we address this problem through identification of Arabidopsis INCURVATA11 (ICU11) as a Polycomb Repressive Complex 2 accessory protein. ICU11 robustly immunoprecipitated in vivo with PRC2 core components and the accessory proteins, EMBRYONIC FLOWER 1 (EMF1), LIKE HETEROCHROMATIN PROTEIN1 (LHP1), and TELOMERE_REPEAT_BINDING FACTORS (TRBs). ICU11 encodes a 2-oxoglutarate-dependent dioxygenase, an activity associated with histone demethylation in other organisms, and mutant plants show defects in multiple aspects of the Arabidopsis epigenome. To investigate its primary molecular function we identified the Arabidopsis FLOWERING LOCUS C (FLC) as a direct target and found icu11 disrupted the cold-induced, Polycomb-mediated silencing underlying vernalization. icu11 prevented reduction in H3K36me3 levels normally seen during the early cold phase, supporting a role for ICU11 in H3K36me3 demethylation. This was coincident with an attenuation of H3K27me3 at the internal nucleation site in FLC, and reduction in H3K27me3 levels across the body of the gene after plants were returned to the warm. Thus, ICU11 is required for the cold-induced epigenetic switching between the mutually exclusive chromatin states at FLC, from the active H3K36me3 state to the silenced H3K27me3 state. These data support the importance of physical coupling of histone modification activities to promote epigenetic switching between opposing chromatin states.},
  author       = {Bloomer, Rebecca H. and Hutchison, Claire E. and Bäurle, Isabel and Walker, James and Fang, Xiaofeng and Perera, Pumi and Velanis, Christos N. and Gümüs, Serin and Spanos, Christos and Rappsilber, Juri and Feng, Xiaoqi and Goodrich, Justin and Dean, Caroline},
  issn         = {0027-8424},
  journal      = {Proceedings of the National Academy of Sciences},
  keywords     = {Multidisciplinary},
  number       = {28},
  pages        = {16660--16666},
  publisher    = {Proceedings of the National Academy of Sciences},
  title        = {{The  Arabidopsis epigenetic regulator ICU11 as an accessory protein of polycomb repressive complex 2}},
  doi          = {10.1073/pnas.1920621117},
  volume       = {117},
  year         = {2020},
}

@article{12189,
  abstract     = {Meiotic crossovers (COs) are important for reshuffling genetic information between homologous chromosomes and they are essential for their correct segregation. COs are unevenly distributed along chromosomes and the underlying mechanisms controlling CO localization are not well understood. We previously showed that meiotic COs are mis-localized in the absence of AXR1, an enzyme involved in the neddylation/rubylation protein modification pathway in Arabidopsis thaliana. Here, we report that in axr1-/-, male meiocytes show a strong defect in chromosome pairing whereas the formation of the telomere bouquet is not affected. COs are also redistributed towards subtelomeric chromosomal ends where they frequently form clusters, in contrast to large central regions depleted in recombination. The CO suppressed regions correlate with DNA hypermethylation of transposable elements (TEs) in the CHH context in axr1-/- meiocytes. Through examining somatic methylomes, we found axr1-/- affects DNA methylation in a plant, causing hypermethylation in all sequence contexts (CG, CHG and CHH) in TEs. Impairment of the main pathways involved in DNA methylation is epistatic over axr1-/- for DNA methylation in somatic cells but does not restore regular chromosome segregation during meiosis. Collectively, our findings reveal that the neddylation pathway not only regulates hormonal perception and CO distribution but is also, directly or indirectly, a major limiting pathway of TE DNA methylation in somatic cells.},
  author       = {Christophorou, Nicolas and She, Wenjing and Long, Jincheng and Hurel, Aurélie and Beaubiat, Sébastien and Idir, Yassir and Tagliaro-Jahns, Marina and Chambon, Aurélie and Solier, Victor and Vezon, Daniel and Grelon, Mathilde and Feng, Xiaoqi and Bouché, Nicolas and Mézard, Christine},
  issn         = {1553-7404},
  journal      = {PLOS Genetics},
  keywords     = {Cancer Research, Genetics (clinical), Genetics, Molecular Biology, Ecology, Evolution, Behavior and Systematics},
  number       = {6},
  publisher    = {Public Library of Science (PLoS)},
  title        = {{AXR1 affects DNA methylation independently of its role in regulating meiotic crossover localization}},
  doi          = {10.1371/journal.pgen.1008894},
  volume       = {16},
  year         = {2020},
}

@article{12310,
  abstract     = {Let  be a sequence of points on an elliptic curve defined over a number field K. In this paper, we study the denominators of the x-coordinates of this sequence. We prove that, if Q is a torsion point of prime order, then for n large enough there always exists a primitive divisor. Later on, we show the link between the study of the primitive divisors and a Lang-Trotter conjecture. Indeed, given two points P and Q on the elliptic curve, we prove a lower bound for the number of primes p such that P is in the orbit of Q modulo p.},
  author       = {Verzobio, Matteo},
  issn         = {0022-314X},
  journal      = {Journal of Number Theory},
  keywords     = {Algebra and Number Theory},
  number       = {4},
  pages        = {378--390},
  publisher    = {Elsevier},
  title        = {{Primitive divisors of sequences associated to elliptic curves}},
  doi          = {10.1016/j.jnt.2019.09.003},
  volume       = {209},
  year         = {2020},
}

@article{12593,
  abstract     = {Rock debris can accumulate on glacier surfaces and dramatically reduce glacier melt. The structure of a debris cover is unique to each glacier and sensitive to climate. Despite this, debris cover has been omitted from global glacier models and forecasts of their response to a changing climate. Fundamental to resolving these omissions is a global map of debris cover and an estimate of its future spatial evolution. Here we use Landsat imagery and a detailed correction to the Randolph Glacier Inventory to show that 7.3% of mountain glacier area is debris covered and over half of Earth’s debris is concentrated in three regions: Alaska (38.6% of total debris-covered area), Southwest Asia (12.6%) and Greenland (12.0%). We use a set of new metrics, which include stage, the current position of a glacier on its trajectory towards reaching its spatial carrying capacity of debris cover, to quantify the state of glaciers. Debris cover is present on 44% of Earth’s glaciers and prominent (>1.0 km2) on 15%. Of Earth’s glaciers, 20% have a substantial percentage of debris cover for which the net stage is 36% and the bulk of individual glaciers have evolved beyond an optimal moraine configuration favourable for debris-cover expansion. Use of this dataset in global-scale models will enable improved estimates of melt over 10.6% of the global glacier domain.},
  author       = {Herreid, Sam and Pellicciotti, Francesca},
  issn         = {1752-0908},
  journal      = {Nature Geoscience},
  keywords     = {General Earth and Planetary Sciences},
  number       = {9},
  pages        = {621--627},
  publisher    = {Springer Nature},
  title        = {{The state of rock debris covering Earth’s glaciers}},
  doi          = {10.1038/s41561-020-0615-0},
  volume       = {13},
  year         = {2020},
}

@article{12594,
  abstract     = {Information about end-of-winter spatial distribution of snow depth is important for seasonal forecasts of spring/summer streamflow in high-mountain regions. Nevertheless, such information typically relies upon extrapolation from a sparse network of observations at low elevations. Here, we test the potential of high-resolution snow depth data derived from optical stereophotogrammetry of Pléiades satellites for improving the representation of snow depth initial conditions (SDICs) in a glacio-hydrological model and assess potential improvements in the skill of snowmelt and streamflow simulations in a high-elevation Andean catchment. We calibrate model parameters controlling glacier mass balance and snow cover evolution using ground-based and satellite observations, and consider the relative importance of accurate estimates of SDICs compared to model parameters and forcings. We find that Pléiades SDICs improve the simulation of snow-covered area, glacier mass balance, and monthly streamflow compared to alternative SDICs based upon extrapolation of meteorological variables or statistical methods to estimate SDICs based upon topography. Model simulations are found to be sensitive to SDICs in the early spring (up to 48% variability in modeled streamflow compared to the best estimate model), and to temperature gradients in all months that control albedo and melt rates over a large elevation range (>2,400 m). As such, appropriately characterizing the distribution of total snow volume with elevation is important for reproducing total streamflow and the proportions of snowmelt. Therefore, optical stereo-photogrammetry offers an advantage for obtaining SDICs that aid both the timing and magnitude of streamflow simulations, process representation (e.g., snow cover evolution) and has the potential for large spatial domains.},
  author       = {Shaw, Thomas E. and Caro, Alexis and Mendoza, Pablo and Ayala, Álvaro and Pellicciotti, Francesca and Gascoin, Simon and McPhee, James},
  issn         = {1944-7973},
  journal      = {Water Resources Research},
  keywords     = {Water Science and Technology},
  number       = {8},
  publisher    = {American Geophysical Union},
  title        = {{The utility of optical satellite winter snow depths for initializing a glacio‐hydrological model of a High‐Elevation, Andean catchment}},
  doi          = {10.1029/2020wr027188},
  volume       = {56},
  year         = {2020},
}

@article{12595,
  abstract     = {The seasonal dynamic changes of Tibetan glaciers have seen little prior investigation, despite the increase in geodetic studies of multi-year changes. This study compares seasonal glacier dynamics (“cold” and “warm” seasons) in the ablation zone of Parlung No. 4 Glacier, a temperate glacier in the monsoon-influenced southeastern Tibetan Plateau, by using repeat unpiloted aerial vehicle (UAV) surveys combined with Structure-from-Motion (SfM) photogrammetry and ground stake measurements. Our results showed that the surveyed ablation zone had a mean change of −2.7 m of ice surface elevation during the period of September 2018 to October 2019 but is characterized by significant seasonal cyclic variations with ice surface elevation lifting (+2.0 m) in the cold season (September 2018 to June 2019) but lowering (−4.7 m) in the warm season (June 2019 to October 2019). Over an annual timescale, surface lowering was greatly suppressed by the resupply of ice from the glacier’s accumulation area—the annual emergence velocity compensates for about 55% of surface ablation in our study area. Cold season emergence velocities (3.0 ± 1.2 m) were ~5-times larger than those observed in the warm season (0.6 ± 1.0 m). Distinct spring precipitation patterns may contribute to these distinct seasonal signals. Such seasonal dynamic conditions are possibly critical for different glacier responses to climate change in this region of the Tibetan Plateau, and perhaps further afield.},
  author       = {Yang, Wei and Zhao, Chuanxi and Westoby, Matthew and Yao, Tandong and Wang, Yongjie and Pellicciotti, Francesca and Zhou, Jianmin and He, Zhen and Miles, Evan},
  issn         = {2072-4292},
  journal      = {Remote Sensing},
  number       = {15},
  publisher    = {MDPI},
  title        = {{Seasonal dynamics of a temperate Tibetan glacier revealed by high-resolution UAV photogrammetry and in situ measurements}},
  doi          = {10.3390/rs12152389},
  volume       = {12},
  year         = {2020},
}

@article{12596,
  abstract     = {As glaciers adjust their size in response to climate variations, long-term changes in meltwater production can be expected, affecting the local availability of water resources. We investigate glacier runoff in the period 1955–2016 in the Maipo River basin (4843 km2, 33.0–34.3∘ S, 69.8–70.5∘ W), in the semiarid Andes of Chile. The basin contains more than 800 glaciers, which cover 378 km2 in total (inventoried in 2000). We model the mass balance and runoff contribution of 26 glaciers with the physically oriented and fully distributed TOPKAPI (Topographic Kinematic Approximation and Integration)-ETH glacio-hydrological model and extrapolate the results to the entire basin. TOPKAPI-ETH is run at a daily time step using several glaciological and meteorological datasets, and its results are evaluated against streamflow records, remotely sensed snow cover, and geodetic mass balances for the periods 1955–2000 and 2000–2013. Results show that in 1955–2016 glacier mass balance had a general decreasing trend as a basin average but also had differences between the main sub-catchments. Glacier volume decreased by one-fifth (from 18.6±4.5 to 14.9±2.9 km3). Runoff from the initially glacierized areas was 177±25 mm yr−1 (16±7 % of the total contributions to the basin), but it shows a decreasing sequence of maxima, which can be linked to the interplay between a decrease in precipitation since the 1980s and the reduction of ice melt. Glaciers in the Maipo River basin will continue retreating because they are not in equilibrium with the current climate. In a hypothetical constant climate scenario, glacier volume would reduce to 81±38 % of the year 2000 volume, and glacier runoff would be 78±30 % of the 1955–2016 average. This would considerably decrease the drought mitigation capacity of the basin.},
  author       = {Ayala, Álvaro and Farías-Barahona, David and Huss, Matthias and Pellicciotti, Francesca and McPhee, James and Farinotti, Daniel},
  issn         = {1994-0424},
  journal      = {The Cryosphere},
  keywords     = {Earth-Surface Processes, Water Science and Technology},
  number       = {6},
  pages        = {2005--2027},
  publisher    = {Copernicus Publications},
  title        = {{Glacier runoff variations since 1955 in the Maipo River basin, in the semiarid Andes of central Chile}},
  doi          = {10.5194/tc-14-2005-2020},
  volume       = {14},
  year         = {2020},
}

@article{12597,
  abstract     = {We examine the spatial patterns of near-surface air temperature (Ta) over a melting glacier using a multi-annual dataset from McCall Glacier, Alaska. The dataset consists of a 10-year (2005–2014) meteorological record along the glacier centreline up to an upper glacier cirque, spanning an elevation difference of 900 m. We test the validity of on-glacier linear lapse rates, and a model that calculates Ta based on the influence of katabatic winds and other heat sources along the glacier flow line. During the coldest hours of each summer (10% of time), average lapse rates across the entire glacier range from −4.7 to −6.7°C km−1, with a strong relationship between Ta and elevation (R2 > 0.7). During warm conditions, Ta shows more complex, non-linear patterns that are better explained by the flow line-dependent model, reducing errors by up to 0.5°C compared with linear lapse rates, although more uncertainty might be associated with these observations due to occasionally poor sensor ventilation. We conclude that Ta spatial distribution can vary significantly from year to year, and from one glacier section to another. Importantly, extrapolations using linear lapse rates from the ablation zone might lead to large underestimations of Ta on the upper glacier areas.},
  author       = {Troxler, Patrick and Ayala, Álvaro and Shaw, Thomas E. and Nolan, Matt and Brock, Ben W. and Pellicciotti, Francesca},
  issn         = {1727-5652},
  journal      = {Journal of Glaciology},
  keywords     = {Earth-Surface Processes},
  number       = {257},
  pages        = {386--400},
  publisher    = {Cambridge University Press},
  title        = {{Modelling spatial patterns of near-surface air temperature over a decade of melt seasons on McCall Glacier, Alaska}},
  doi          = {10.1017/jog.2020.12},
  volume       = {66},
  year         = {2020},
}

@article{12598,
  abstract     = {Obtaining detailed information about high mountain snowpacks is often limited by insufficient ground-based observations and uncertainty in the (re)distribution of solid precipitation. We utilize high-resolution optical images from Pléiades satellites to generate a snow depth map, at a spatial resolution of 4 m, for a high mountain catchment of central Chile. Results are negatively biased (median difference of −0.22 m) when compared against observations from a terrestrial Light Detection And Ranging scan, though replicate general snow depth variability well. Additionally, the Pléiades dataset is subject to data gaps (17% of total pixels), negative values for shallow snow (12%), and noise on slopes >40–50° (2%). We correct and filter the Pléiades snow depths using surface classification techniques of snow-free areas and a random forest model for data gap filling. Snow depths (with an estimated error of ~0.36 m) average 1.66 m and relate well to topographical parameters such as elevation and northness in a similar way to previous studies. However, estimations of snow depth based upon topography (TOPO) or physically based modeling (DBSM) cannot resolve localized processes (i.e., avalanching or wind scouring) that are detected by Pléiades, even when forced with locally calibrated data. Comparing these alternative model approaches to corrected Pléiades snow depths reveals total snow volume differences between −28% (DBSM) and +54% (TOPO) for the catchment and large differences across most elevation bands. Pléiades represents an important contribution to understanding snow accumulation at sparsely monitored catchments, though ideally requires a careful systematic validation procedure to identify catchment-scale biases and errors in the snow depth derivation.},
  author       = {Shaw, Thomas E. and Gascoin, Simon and Mendoza, Pablo A. and Pellicciotti, Francesca and McPhee, James},
  issn         = {1944-7973},
  journal      = {Water Resources Research},
  keywords     = {Water Science and Technology},
  number       = {2},
  publisher    = {American Geophysical Union},
  title        = {{Snow depth patterns in a high mountain Andean catchment from satellite optical tristereoscopic remote sensing}},
  doi          = {10.1029/2019wr024880},
  volume       = {56},
  year         = {2020},
}