Publications

@article{acp-21-951-2021,

title = {Aircraft-based inversions quantify the importance of wetlands and livestock for Upper Midwest methane emissions},

author = {X Yu and D B Millet and K C Wells and D K Henze and H Cao and T J Griffis and E A Kort and G Plant and M J Deventer and R K Kolka and D T Roman and K J Davis and A R Desai and B C Baier and K McKain and A C Czarnetzki and A A Bloom},

url = {https://acp.copernicus.org/articles/21/951/2021/},

doi = {10.5194/acp-21-951-2021},

year  = {2021},

date = {2021-01-01},

journal = {Atmospheric Chemistry and Physics},

volume = {21},

number = {2},

pages = {951--971},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1029/2020GL090996,

title = {Simultaneous Measurements of O3 and HCOOH Vertical Fluxes Indicate Rapid In-Canopy Terpene Chemistry Enhances O3 Removal Over Mixed Temperate Forests},

author = {Michael P Vermeuel and Patricia A Cleary and Ankur R Desai and Timothy H Bertram},

url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL090996},

doi = {https://doi.org/10.1029/2020GL090996},

year  = {2021},

date = {2021-01-01},

journal = {Geophysical Research Letters},

volume = {48},

number = {3},

pages = {e2020GL090996},

abstract = {Abstract Dry deposition, the second largest removal process of ozone (O3) in the troposphere, plays a role in controlling the natural variability of surface O3 concentrations. Terrestrial ecosystems remove O3 either through stomatal uptake or nonstomatal processes. In chemical transport models, nonstomatal pathways are roughly constrained and may not correctly capture total O3 loss. To address this, the first simultaneous eddy covariance measurements of O3 and formic acid (HCOOH), a tracer of in-canopy oxidation of biogenic terpenes, were made in a mixed temperate forest in Northern Wisconsin. Daytime maximum O3 deposition velocities, vd (O3), ranged between 0.5 and 1.2 cm s−1. Comparison of observed vd (O3) with observationally constrained estimates of stomatal uptake and parameterized estimates of cuticular and soil uptake reveal a large (10%–90%) residual nonstomatal contribution to vd (O3). The residual downward flux of O3 was well correlated with measurements of HCOOH upward flux, suggesting unaccounted for in-canopy gas-phase chemistry.},

note = {e2020GL090996 2020GL090996},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{CHU2021108350,

title = {Representativeness of Eddy-Covariance flux footprints for areas surrounding AmeriFlux sites},

author = {Housen Chu and Xiangzhong Luo and Zutao Ouyang and Stephen W Chan and Sigrid Dengel and Sébastien C Biraud and Margaret S Torn and Stefan Metzger and Jitendra Kumar and Altaf M Arain and Tim J Arkebauer and Dennis Baldocchi and Carl Bernacchi and Dave Billesbach and Andrew T Black and Peter D Blanken and Gil Bohrer and Rosvel Bracho and Shannon Brown and Nathaniel A Brunsell and Jiquan Chen and Xingyuan Chen and Kenneth Clark and Ankur R Desai and Tomer Duman and David Durden and Silvano Fares and Inke Forbrich and John A Gamon and Christopher M Gough and Timothy Griffis and Manuel Helbig and David Hollinger and Elyn Humphreys and Hiroki Ikawa and Hiroki Iwata and Yang Ju and John F Knowles and Sara H Knox and Hideki Kobayashi and Thomas Kolb and Beverly Law and Xuhui Lee and Marcy Litvak and Heping Liu and William J Munger and Asko Noormets and Kim Novick and Steven F Oberbauer and Walter Oechel and Patty Oikawa and Shirley A Papuga and Elise Pendall and Prajaya Prajapati and John Prueger and William L Quinton and Andrew D Richardson and Eric S Russell and Russell L Scott and Gregory Starr and Ralf Staebler and Paul C Stoy and Ellen Stuart-Haëntjens and Oliver Sonnentag and Ryan C Sullivan and Andy Suyker and Masahito Ueyama and Rodrigo Vargas and Jeffrey D Wood and Donatella Zona},

url = {https://www.sciencedirect.com/science/article/pii/S0168192321000332},

doi = {https://doi.org/10.1016/j.agrformet.2021.108350},

issn = {0168-1923},

year  = {2021},

date = {2021-01-01},

journal = {Agricultural and Forest Meteorology},

volume = {301-302},

pages = {108350},

abstract = {Large datasets of greenhouse gas and energy surface-atmosphere fluxes measured with the eddy-covariance technique (e.g., FLUXNET2015, AmeriFlux BASE) are widely used to benchmark models and remote-sensing products. This study addresses one of the major challenges facing model-data integration: To what spatial extent do flux measurements taken at individual eddy-covariance sites reflect model- or satellite-based grid cells? We evaluate flux footprints—the temporally dynamic source areas that contribute to measured fluxes—and the representativeness of these footprints for target areas (e.g., within 250–3000 m radii around flux towers) that are often used in flux-data synthesis and modeling studies. We examine the land-cover composition and vegetation characteristics, represented here by the Enhanced Vegetation Index (EVI), in the flux footprints and target areas across 214 AmeriFlux sites, and evaluate potential biases as a consequence of the footprint-to-target-area mismatch. Monthly 80% footprint climatologies vary across sites and through time ranging four orders of magnitude from 103 to 107 m2 due to the measurement heights, underlying vegetation- and ground-surface characteristics, wind directions, and turbulent state of the atmosphere. Few eddy-covariance sites are located in a truly homogeneous landscape. Thus, the common model-data integration approaches that use a fixed-extent target area across sites introduce biases on the order of 4%–20% for EVI and 6%–20% for the dominant land cover percentage. These biases are site-specific functions of measurement heights, target area extents, and land-surface characteristics. We advocate that flux datasets need to be used with footprint awareness, especially in research and applications that benchmark against models and data products with explicit spatial information. We propose a simple representativeness index based on our evaluations that can be used as a guide to identify site-periods suitable for specific applications and to provide general guidance for data use.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{10.3897/rio.7.e63850,

title = {BII-Implementation: The causes and consequences of plant biodiversity across scales in a rapidly changing world},

author = {Jeannine Cavender-Bares and Peter B Reich and Philip A Townsend and Arindam Banerjee and Ethan Butler and Ankur Desai and Amanda Gevens and Sarah E Hobbie and Forest Isbell and Etienne Laliberté and José Eduardo Meireles and Holly Menninger and Ryan P Pavlick and Jesús Pinto-Ledezma and Caitlin Potter and Meredith C Schuman and Nathan Springer and Artur Stefanski and Pankaj Trivedi and Amy Trowbridge and Laura Williams and Charles G Willis and Ya Yang},

url = {https://doi.org/10.3897/rio.7.e63850},

doi = {10.3897/rio.7.e63850},

year  = {2021},

date = {2021-01-01},

journal = {Research Ideas and Outcomes},

volume = {7},

pages = {e63850},

publisher = {Pensoft Publishers},

abstract = {The proposed Biology Integration Institute will bring together two major research institutions in the Upper Midwest—the University of Minnesota (UMN) and University of Wisconsin-Madison (UW)—to investigate the causes and consequences of plant biodiversity across scales in a rapidly changing world—from genes and molecules within cells and tissues to communities, ecosystems, landscapes and the biosphere. The Institute focuses on plant biodiversity, defined broadly to encompass the heterogeneity within life that occurs from the smallest to the largest biological scales. A premise of the Institute is that life is envisioned as occurring at different scales nested within several contrasting conceptions of biological hierarchies, defined by the separate but related fields of physiology, evolutionary biology and ecology. The Institute will emphasize the use of ‘spectral biology’—detection of biological properties based on the interaction of light energy with matter—and process-oriented predictive models to investigate the processes by which biological components at one scale give rise to emergent properties at higher scales. Through an iterative process that harnesses cutting edge technologies to observe a suite of carefully designed empirical systems—including the National Ecological Observatory Network (NEON) and some of the world’s longest running and state-of-the-art global change experiments—the Institute will advance biological understanding and theory of the causes and consequences of changes in biodiversity and at the interface of plant physiology, ecology and evolution.INTELLECTUAL MERITThe Institute brings together a diverse, gender-balanced and highly productive team with significant leadership experience that spans biological disciplines and career stages and is poised to integrate biology in new ways. Together, the team will harness the potential of spectral biology, experiments, observations and synthetic modeling in a manner never before possible to transform understanding of how variation within and among biological scales drives plant and ecosystem responses to global change over diurnal, seasonal and millennial time scales. In doing so, it will use and advance state-of-the-art theory. The institute team posits that the designed projects will unearth transformative understanding and biological rules at each of the various scales that will enable an unprecedented capacity to discern the linkages between physiological, ecological and evolutionary processes in relation to the multi-dimensional nature of biodiversity in this time of massive planetary change. A strength of the proposed Institute is that it leverages prior federal investments in research and formalizes partnerships with foreign institutions heavily invested in related biodiversity research. Most of the planned projects leverage existing research initiatives, infrastructure, working groups, experiments, training programs, and public outreach infrastructure, all of which are already highly synergistic and collaborative, and will bring together members of the overall research and training team.BROADER IMPACTSA central goal of the proposed Institute is to train the next generation of diverse integrative biologists. Post-doctoral, graduate student and undergraduate trainees, recruited from non-traditional and underrepresented groups, including through formal engagement with Native American communities, will receive a range of mentoring and training opportunities. Annual summer training workshops will be offered at UMN and UW as well as training experiences with the Global Change and Biodiversity Research Priority Program (URPP-GCB) at the University of Zurich (UZH) and through the Canadian Airborne Biodiversity Observatory (CABO). The Institute will engage diverse K-12 audiences, the general public and Native American communities through Market Science modules, Minute Earth videos, a museum exhibit and public engagement and educational activities through the Bell Museum of Natural History, the Cedar Creek Ecosystem Science Reserve (CCESR) and the Wisconsin Tribal Conservation Association.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{YANG2021125959,

title = {A Bayesian adaptive reservoir operation framework incorporating streamflow non-stationarity},

author = {Guang Yang and Benjamin Zaitchik and Hamada Badr and Paul Block},

url = {https://www.sciencedirect.com/science/article/pii/S0022169421000068},

doi = {https://doi.org/10.1016/j.jhydrol.2021.125959},

issn = {0022-1694},

year  = {2021},

date = {2021-01-01},

journal = {Journal of Hydrology},

volume = {594},

pages = {125959},

abstract = {Water reservoir operating rules are typically derived based on the assumption of streamflow stationarity, however, this assumption could be undermined by climate change. Adaptive reservoir operation is one of the most effective strategies to support water resources management under non-stationarity, yet until now, adaptive strategies considering non-stationarity across multiple time scales are rarely investigated. We propose an adaptive reservoir operation framework that incorporates streamflow non-stationarity across time scales simultaneously. Specifically, we first decompose the streamflow into four frequency categories to detect non-stationarity features through reservoir operation simulations. Next, we incorporate the non-stationarity information from each frequency category into adaptive reservoir operation by using Bayesian Model Averaging. We apply this framework to reservoir operation of the Grand Ethiopian Renaissance Dam on the Blue Nile River and evaluate its effectiveness with streamflow simulated from 21 general circulation models (GCMs) for two greenhouse gases emission scenarios. We find that streamflow non-stationarity from all GCMs varies by future period and frequency category. The proposed Bayesian adaptive reservoir operation framework can detect streamflow non-stationarity across all frequency categories and predominantly outperforms conventional adaptive strategies, especially in terms of firm power output. In general, firm output increases under the Bayesian framework as the power generation reliability increases. The proposed framework offers a robust approach to identify adaptive strategies for reservoir operation to address streamflow non-stationarity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1111/ele.13667,

title = {Forest responses to last-millennium hydroclimate variability are governed by spatial variations in ecosystem sensitivity},

author = {Christine R Rollinson and Andria Dawson and Ann M Raiho and John W Williams and Michael C Dietze and Thomas Hickler and Stephen T Jackson and Jason McLachlan and David JP Moore and Benjamin Poulter and Tristan Quaife and Jörg Steinkamp and Mathias Trachsel},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.13667},

doi = {https://doi.org/10.1111/ele.13667},

year  = {2020},

date = {2020-12-29},

journal = {Ecology Letters},

volume = {24},

number = {3},

pages = {498-508},

abstract = {Abstract Forecasts of future forest change are governed by ecosystem sensitivity to climate change, but ecosystem model projections are under-constrained by data at multidecadal and longer timescales. Here, we quantify ecosystem sensitivity to centennial-scale hydroclimate variability, by comparing dendroclimatic and pollen-inferred reconstructions of drought, forest composition and biomass for the last millennium with five ecosystem model simulations. In both observations and models, spatial patterns in ecosystem responses to hydroclimate variability are strongly governed by ecosystem sensitivity rather than climate exposure. Ecosystem sensitivity was higher in models than observations and highest in simpler models. Model-data comparisons suggest that interactions among biodiversity, demography and ecophysiology processes dampen the sensitivity of forest composition and biomass to climate variability and change. Integrating ecosystem models with observations from timescales extending beyond the instrumental record can better understand and forecast the mechanisms regulating forest sensitivity to climate variability in a complex and changing world.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Cohen2020,

title = {Divergent consensuses on Arctic amplification influence on midlatitude severe winter weather},

author = {J Cohen and X Zhang and J Francis and T Jung and R Kwok and J Overland and T J Ballinger and U S Bhatt and H W Chen and D Coumou and S Feldstein and H Gu and D Handorf and G Henderson and M Ionita and M Kretschmer and F Laliberte and S Lee and H W Linderholm and W Maslowski and Y Peings and K Pfeiffer and I Rigor and T Semmler and J Stroeve and P C Taylor and S Vavrus and T Vihma and S Wang and M Wendisch and Y Wu and J Yoon},

url = {https://www.nature.com/articles/s41558-019-0662-y},

doi = {10.1038/s41558-019-0662-y},

issn = {1758-6798},

year  = {2020},

date = {2020-12-23},

journal = {Nature Climate Change},

volume = {10},

number = {1},

pages = {20-29},

abstract = {The Arctic has warmed more than twice as fast as the global average since the late twentieth century, a phenomenon known as Arctic amplification (AA). Recently, there have been considerable advances in understanding the physical contributions to AA, and progress has been made in understanding the mechanisms that link it to midlatitude weather variability. Observational studies overwhelmingly support that AA is contributing to winter continental cooling. Although some model experiments support the observational evidence, most modelling results show little connection between AA and severe midlatitude weather or suggest the export of excess heating from the Arctic to lower latitudes. Divergent conclusions between model and observational studies, and even intramodel studies, continue to obfuscate a clear understanding of how AA is influencing midlatitude weather.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1111/geb.13238,

title = {Caught in a bottleneck: Habitat loss for woolly mammoths in central North America and the ice-free corridor during the last deglaciation},

author = {Yue Wang and Chris Widga and Russell W Graham and Jenny L McGuire and Warren Porter and David Wårlind and John W Williams},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/geb.13238},

doi = {https://doi.org/10.1111/geb.13238},

year  = {2020},

date = {2020-12-19},

journal = {Global Ecology and Biogeography},

volume = {30},

number = {2},

pages = {527-542},

abstract = {Abstract Aim Identifying how climate change, habitat loss, and corridors interact to influence species survival or extinction is critical to understanding macro-scale biodiversity dynamics under changing environments. In North America, the ice-free corridor was the only major pathway for northward migration by megafaunal species during the last deglaciation. However, the timing and interplay among the late Quaternary megafaunal extinctions, climate change, habitat structure, and the opening and reforestation of the ice-free corridor have been unclear. Location North America. Time period 15–10 ka. Major taxa studied Woolly mammoth (Mammuthus primigenius). Methods For central North America and the ice-free corridor between 15 and 10 ka, we used a series of models and continental-scale datasets to reconstruct habitat characteristics and assess habitat suitability. The models and datasets include biophysical and statistical niche models Niche Mapper and Maxent, downscaled climate simulations from CCSM3 SynTraCE, LPJ-GUESS simulations of net primary productivity (NPP) and woody cover, and woody cover based upon fossil pollen from Neotoma. Results The ice-free corridor may have been of limited suitability for traversal by mammoths and other grazers due to persistently low productivity by herbaceous plants and quick reforestation after opening 14 ka. Simultaneously, rapid reforestation and decreased forage productivity may have led to declining habitat suitability in central North America. This was possibly amplified by a positive feedback loop driven by reduced herbivory pressures, as mammoth population decline led to the further loss of open habitat. Main conclusions Declining habitat availability south of the Laurentide Ice Sheet and limited habitat availability in the ice-free corridor were contributing factors in North American extinctions of woolly mammoths and other large grazers that likely operated synergistically with anthropogenic pressures. The role of habitat loss and attenuated corridor suitability for the woolly mammoth extinction reinforce the critical importance of protected habitat connectivity during changing climates, particularly for large vertebrates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zhang2020,

title = {Integrating climate prediction and regionalization into an agro-economic model to guide agricultural planning},

author = {Ying Zhang and Liangzhi You and Donghoon Lee and Paul Block},

url = {https://doi.org/10.1007/s10584-019-02559-7},

doi = {10.1007/s10584-019-02559-7},

issn = {1573-1480},

year  = {2020},

date = {2020-12-02},

journal = {Climatic Change},

volume = {158},

number = {3},

pages = {435-451},

abstract = {Advanced skill in seasonal climate prediction coupled with sectoral decision models can provide decision makers with opportunities to benefit or reduce unnecessary losses. Such approaches are particularly beneficial to rainfed agriculture, the livelihood choice for the majority of the world's poor population, for which yields are highly sensitive to climate conditions. However, a notable gap still exists between scientific communities producing predictions and the end users who may actually realize the benefits. In this study, an interdisciplinary approach connecting climate prediction to agricultural planning is adopted to address this gap. An ex ante evaluation of seasonal precipitation prediction is assessed using an agro-economic equilibrium model to simulate Ethiopia's national economy, accounting for interannual climate variability and prediction-guided agricultural responses. Given the high spatial variability in Ethiopian precipitation, delineation of homogeneous climatic regions (i.e., regionalization) is also considered in addition to growing season precipitation prediction. The model provides perspectives across various economic indices (e.g., gross domestic product, calorie consumption, and poverty rate) at aggregated (national) and disaggregated (zonal) scales. Model results illustrate the key influence of climate on the Ethiopian economy, and prospects for positive net benefits under a prediction-guided agricultural planning (e.g., reallocation of crop types) strategy, as compared with static business-as-usual agricultural practices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1029/2019JG005623,

title = {Comparing Spatial and Temporal Variation of Lake-Atmosphere Carbon Dioxide Fluxes Using Multiple Methods},

author = {Angela K Baldocchi and David E Reed and Luke C Loken and Emily H Stanley and Hayley Huerd and Ankur R Desai},

url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JG005623},

doi = {https://doi.org/10.1029/2019JG005623},

year  = {2020},

date = {2020-12-02},

journal = {Journal of Geophysical Research: Biogeosciences},

volume = {125},

number = {12},

pages = {e2019JG005623},

abstract = {Abstract Lakes emit globally significant amounts of carbon dioxide (CO2) to the atmosphere, but quantifying these rates for individual lakes is extremely challenging. The exchange of CO2 across the air-water interface is driven by physical, chemical, and biological processes in both the lake and the atmosphere that vary at multiple spatial and temporal scales. None of the methods we use to estimate CO2 flux fully capture this heterogeneous gas exchange. Here, we compared concurrent CO2 flux estimates from a single lake based on commonly used methods. These include floating chambers (FCs), eddy covariance (EC), and two concentration gradient-based methods labeled fixed (F-pCO₂) and spatial (S-pCO₂). At the end of summer, cumulative carbon fluxes were similar between EC, F-pCO₂, and S-pCO₂ methods (−4, −4, and −9.5 gC m−2), while methods diverged in directionality of fluxes during the fall turnover period (−50, 43, and 38 gC m−2). Collectively, these results highlight the discrepancies among methods and the need to acknowledge the uncertainty when using any of them to approximate this heterogeneous flux.},

note = {e2019JG005623 2019JG005623},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{POE2020108188,

title = {Geospatial coherence of surface-atmosphere fluxes in the upper Great Lakes region},

author = {Jeralyn Poe and David E Reed and Michael Abraha and Jiquan Chen and Kyla M Dahlin and Ankur R Desai},

url = {https://www.sciencedirect.com/science/article/pii/S0168192320302902},

doi = {https://doi.org/10.1016/j.agrformet.2020.108188},

issn = {0168-1923},

year  = {2020},

date = {2020-12-01},

journal = {Agricultural and Forest Meteorology},

volume = {295},

pages = {108188},

abstract = {Surface-atmosphere fluxes are known to vary at multiple time scales, but uncertainty is high as to how fluxes change spatially within regions. With an increase in the number of eddy covariance towers, we are now able to examine the geospatial coherence of ecosystem fluxes, using time-series correlation. Eighteen sites from Michigan and Wisconsin were used in this study, ranging from 100 m to 600 km apart. Surface-atmosphere fluxes from a six-month period were used to quantify spatial coherence on a pair-wise basis. Using geospatial statistics, carbon and sensible heat (H) fluxes were found to be 95% correlated directly outside of their flux footprint and 56% correlated up to a distance of ~35 km. Latent (LE) and momentum (τ) fluxes were less correlated, 83% directly outside of their flux footprint and 40% at a distance of ~130 km albeit, at a much larger spatial distance than for the carbon and sensible heat fluxes. All fluxes showed strong spectral resonance at diel and seasonal timescales, with 1-, 2- and 3-month periods being common modes of variability among H, LE, and τ fluxes. Results based on Empirical Orthogonal Function show distinct transitions of net ecosystem exchange from fall to winter before photosynthesis or respiration while H and τ do not exhibit coherent trends. This work demonstrates the potential of quantifying geospatial coherence of surface-atmosphere fluxes in the Midwestern United States, with the ability to predict fluxes beyond the spatial limit of a single flux tower footprint. Ultimately, expanding the flux measurements to larger scales would allow better spatial scaling of terrestrial surface-atmosphere fluxes between tower footprint and modeling or remote sensing scales.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Alkama_2020,

title = {Wind amplifies the polar sea ice retreat},

author = {Ramdane Alkama and Ernest N Koffi and Stephen J Vavrus and Thomas Diehl and Jennifer Ann Francis and Julienne Stroeve and Giovanni Forzieri and Timo Vihma and Alessandro Cescatti},

url = {https://doi.org/10.1088/1748-9326/abc379},

doi = {10.1088/1748-9326/abc379},

year  = {2020},

date = {2020-12-01},

journal = {Environmental Research Letters},

volume = {15},

number = {12},

pages = {124022},

publisher = {IOP Publishing},

abstract = {The rapid polar sea ice retreat and its drivers are challenging and still unresolved questions in climate change research. In particular, the relationship between near-surface wind speed and sea ice extent remains unclear for two main reasons: (1) observed wind speeds over Polar Regions are very sparse, and (2) simulated winds by climate models are dependent on subjective parameterizations of boundary layer stratification, ultimately leading to large uncertainty. Here, we use observation-based data (passive microwave sea ice concentration and six different reanalysis datasets) together with output from 26 climate models (from the CMIP5 archive) to quantify the relationships between near-surface wind speed and sea ice concentration over the past 40 years. We find strong inverse relationships between near-surface wind speed and sea ice concentration that are consistent among the six reanalysis datasets. The poleward wind component is particularly increasing in years of reduced sea ice concentration, which contributes to the enhancement of the atmospheric (surface oceanic) poleward heat flux by up to 24 ± 1% (29 ± 2%) in the Arctic and 37 ± 3% (51 ± 3%) in the Antarctic seas, therefore boosting the impact of polar sea ice loss and contributing to polar amplification of climate warming. In addition, our results show a marginal contribution of the dynamical (pushing/opening/compacting) effects of wind on sea ice compared to the thermodynamic effects which in turn play a lower role than the associated change in local surface Autumn–Winter turbulent and Spring–Summer radiative fluxes. Climate models generally produce similar results but with lower magnitude, and one model even simulates the opposite relationship wind/sea-ice. Given the rapid changes in polar climate and the potential impacts on the mid-latitudes, it is urgent that model developments make use of evidence from satellite observations and reanalysis datasets to reduce uncertainties in the representation of relationships between polar winds and sea ice.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Calcote2020,

title = {Late-Holocene climate changes linked to ecosystem shifts in the Northwest Wisconsin Sand Plain, USA},

author = {Randy Calcote and Christopher Nevala-Plagemann and Elizabeth A Lynch and Sara C Hotchkiss},

doi = {https://doi.org/10.1177/0959683620972760},

year  = {2020},

date = {2020-11-20},

journal = {The Holocene},

volume = {31},

issue = {3},

pages = {409–420},

abstract = {Records of century-scale climate variability in the Upper Midwest generally agree that moisture availability increased between 4000 and 3000 cal. yr BP (calendar years before present = 1950 CE), and that there were large, frequent droughts 1000–700 cal. yr BP followed by wetter/cooler conditions. Variability among regional sites, however, remains problematic. In this study we reconstruct climate on the Northwest Wisconsin Sand Plain (NWSP), USA, to identify potential climatic drivers of previously documented changes in vegetation and fire regimes. Oak pollen was replaced by pollen from xeric pine taxa at several sites on the NWSP ~1425 cal. yr BP, accompanied by a change to larger, less frequent charcoal peaks. Another major vegetation change occurred ~700 cal. yr BP, when pollen of the more mesic P. strobus L. (white pine) increased and charcoal influx decreased. We used a vegetation-independent lake-level record to determine whether long-term changes in moisture availability were associated with these ecosystem changes. Decreases in percent organic matter in shallow-water sediment cores from Cheney Lake indicate that the lake level decreased sharply ~1500 cal. yr BP, consistent with the interpretation that the changes in vegetation and fire regime were driven by a severe and previously undocumented drought. The lake level rose again, reaching approximately modern levels by 800–700 cal. yr BP, consistent with the hypothesis of cooler/wetter conditions in the Upper Midwest in the past ~700 years and with the expansion of mesic taxa on the NWSP 700 cal. yr BP.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tadesse_2020,

title = {Forest Drought Response Index (ForDRI): A New Combined Model to Monitor Forest Drought in the Eastern United States},

author = {Tsegaye Tadesse and David Hollinger and Yared Bayissa and Mark Svoboda and Brian Fuchs and Beichen Zhang and Getachew Demissie and Brian Wardlow and Gil Bohrer and Kenneth Clark and et al.},

url = {https://www.mdpi.com/2072-4292/12/21/3605},

doi = {10.3390/rs12213605},

issn = {2072-4292},

year  = {2020},

date = {2020-11-03},

journal = {Remote Sensing},

volume = {12},

number = {21},

pages = {3605},

publisher = {MDPI AG},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Breeden01Nov.2020,

title = {Diagnosing the Influence of a Receding Snow Boundary on Simulated Midlatitude Cyclones Using Piecewise Potential Vorticity Inversion},

author = {Melissa L Breeden and Ryan Clare and Jonathan E Martin and Ankur R Desai},

url = {https://doi.org/10.1175/MWR-D-20-0056.1},

doi = {10.1175/MWR-D-20-0056.1},

year  = {2020},

date = {2020-11-01},

journal = {Monthly Weather Review},

volume = {148},

number = {11},

pages = {4479-4495},

publisher = {American Meteorological Society},

address = {Boston MA, USA},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mehta2020,

title = {Tree cover and diversity modulate the response of carbon storage to precipitation variability in an Indian semi-arid forest},

author = {Nirav Mehta and Sergio Sanchez and Prashanth Marpu and Ankur Desai and NSR Krishayya},

url = {https://www.researchgate.net/publication/345560730_Tree_cover_and_diversity_modulate_the_response_of_carbon_storage_to_precipitation_variability_in_an_Indian_semi-arid_forest},

doi = {10.18520/cs/v119/i9/1517-1525},

year  = {2020},

date = {2020-11-01},

journal = {Current Science},

volume = {119},

pages = {1517-1525},

abstract = {Water availability is the central limiting factor for vegetation carbon allocation in semi-arid forests. However, the sensitivity of this relationship likely varies as a function of total tree cover and tree diversity. In the present study, a set of re-measured semi-arid forest plots in India were analysed to test how sensitive biomass, productivity and soil organic carbon (SOC) accumulation were to variability in precipitation from plot-level and remote sensing solar-induced fluorescence (SIF) measurements. Variability in mean precipitation at zones I and II impacted tree density, recorded as 150 and 400 trees ha-1 respectively. Results show that low tree cover plots had lower woody biomass NPP (NPPwood) and lower SIF sensitivity to inter-annual variation of precipitation. Increment in NPPwood over a five-year period was significantly smaller (P < 0.05) in zone I (0.21 Mg ha-1 year-1 , CI95, 0.14-0.28) than at zone II (2.44 Mg ha-1 year-1 , CI95, 1.43-3.45). Mean annual SOC increment at 0-5 cm depth varied between 0.13 and 0.75 Mg ha-1 year-1 across the study area. Results highlight the importance of tree cover diversity in modulating the response of semi-arid forests to carbon storage across a precipitation gradient.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{10.3389/frwa.2020.578367,

title = {Retrieving Heterogeneous Surface Soil Moisture at 100 m Across the Globe via Fusion of Remote Sensing and Land Surface Parameters},

author = {Jingyi Huang and Ankur R Desai and Jun Zhu and Alfred E Hartemink and Paul C Stoy and Steven P Loheide and Heye R Bogena and Yakun Zhang and Zhou Zhang and Francisco Arriaga},

url = {https://www.frontiersin.org/article/10.3389/frwa.2020.578367},

doi = {10.3389/frwa.2020.578367},

issn = {2624-9375},

year  = {2020},

date = {2020-10-28},

journal = {Frontiers in Water},

volume = {2},

pages = {38},

abstract = {Successful monitoring of soil moisture dynamics at high spatio-temporal resolutions globally is hampered by the heterogeneity of soil hydraulic properties in space and complex interactions between water and the environmental variables that control it. Current soil moisture monitoring schemes via in situ station networks are sparsely distributed while remote sensing satellite soil moisture maps have a very coarse spatial resolution. In this study, an empirical surface soil moisture (SSM) model was established via fusion of in situ continental and regional scale soil moisture networks, remote sensing data (SMAP and Sentinel-1) and high-resolution land surface parameters (e.g., soil texture, terrain) using a quantile random forest (QRF) algorithm. The model had a spatial resolution of 100 m and performed well under cultivated, herbaceous, forest, and shrub soils (overall R^{2} = 0.524},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1029/2020GL090031,

title = {Spatial Fingerprint of Younger Dryas Cooling and Warming in Eastern North America},

author = {David Fastovich and James M Russell and Stephen T Jackson and Teresa R Krause and Shaun A Marcott and John W Williams},

url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL090031},

doi = {https://doi.org/10.1029/2020GL090031},

year  = {2020},

date = {2020-10-22},

journal = {Geophysical Research Letters},

volume = {47},

number = {22},

pages = {e2020GL090031},

abstract = {Abstract The Younger Dryas (YD, 12.9–11.7 ka) is the most recent, near-global interval of abrupt climate change with rates similar to modern global warming. Understanding the causes and biodiversity effects of YD climate changes requires determining the spatial fingerprints of past temperature changes. Here we build pollen-based and branched glycerol dialkyl glycerol tetraether-based temperature reconstructions in eastern North America (ENA) to better understand deglacial temperature evolution. YD cooling was pronounced in the northeastern United States and muted in the north central United States. Florida sites warmed during the YD, while other southeastern sites maintained a relatively stable climate. This fingerprint is consistent with an intensified subtropical high during the YD and demonstrates that interhemispheric responses were more complex spatially in ENA than predicted by the bipolar seesaw model. Reduced-amplitude or antiphased millennial-scale temperature variability in the southeastern United States may support regional hotspots of biodiversity and endemism.},

note = {e2020GL090031 2020GL090031},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1111/gcb.15409,

title = {Beyond ecosystem modeling: A roadmap to community cyberinfrastructure for ecological data-model integration},

author = {Istem Fer and Anthony K Gardella and Alexey N Shiklomanov and Eleanor E Campbell and Elizabeth M Cowdery and Martin G De Kauwe and Ankur Desai and Matthew J Duveneck and Joshua B Fisher and Katherine D Haynes and Forrest M Hoffman and Miriam R Johnston and Rob Kooper and David S LeBauer and Joshua Mantooth and William J Parton and Benjamin Poulter and Tristan Quaife and Ann Raiho and Kevin Schaefer and Shawn P Serbin and James Simkins and Kevin R Wilcox and Toni Viskari and Michael C Dietze},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.15409},

doi = {https://doi.org/10.1111/gcb.15409},

year  = {2020},

date = {2020-10-19},

journal = {Global Change Biology},

volume = {27},

number = {1},

pages = {13-26},

abstract = {Abstract In an era of rapid global change, our ability to understand and predict Earth's natural systems is lagging behind our ability to monitor and measure changes in the biosphere. Bottlenecks to informing models with observations have reduced our capacity to fully exploit the growing volume and variety of available data. Here, we take a critical look at the information infrastructure that connects ecosystem modeling and measurement efforts, and propose a roadmap to community cyberinfrastructure development that can reduce the divisions between empirical research and modeling and accelerate the pace of discovery. A new era of data-model integration requires investment in accessible, scalable, and transparent tools that integrate the expertise of the whole community, including both modelers and empiricists. This roadmap focuses on five key opportunities for community tools: the underlying foundations of community cyberinfrastructure; data ingest; calibration of models to data; model-data benchmarking; and data assimilation and ecological forecasting. This community-driven approach is a key to meeting the pressing needs of science and society in the 21st century.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1111/1365-2745.13517,

title = {More than one way to kill a spruce forest: The role of fire and climate in the late-glacial termination of spruce woodlands across the southern Great Lakes},

author = {Allison M Jensen and David Fastovich and Ben I Watson and Jacquelyn L Gill and Stephen T Jackson and James M Russell and Joseph Bevington and Katherine Hayes and Katherine B Lininger and Claire Rubbelke and Grace C Schellinger and John W Williams},

url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.13517},

doi = {https://doi.org/10.1111/1365-2745.13517},

year  = {2020},

date = {2020-10-08},

journal = {Journal of Ecology},

volume = {109},

number = {1},

pages = {459-477},

abstract = {Abstract In the southern Great Lakes Region, North America, between 19,000 and 8,000 years ago, temperatures rose by 2.5–6.5°C and spruce Picea forests/woodlands were replaced by mixed-deciduous or pine Pinus forests. The demise of Picea forests/woodlands during the last deglaciation offers a model system for studying how changing climate and disturbance regimes interact to trigger declines of dominant species and vegetation-type conversions. The role of rising temperatures in driving the regional demise of Picea forests/woodlands is widely accepted, but the role of fire is poorly understood. We studied the effect of changing fire activity on Picea declines and rates of vegetation composition change using fossil pollen and macroscopic charcoal from five high-resolution lake sediment records. The decline of Picea forests/woodlands followed two distinct patterns. At two sites (Stotzel-Leis and Silver Lake), fire activity reached maximum levels during the declines and both charcoal accumulation rates and fire frequency were significantly and positively associated with vegetation composition change rates. At these sites, Picea declined to low levels by 14 kyr BP and was largely replaced by deciduous hardwood taxa like ash Fraxinus, hop-hornbeam/hornbeam Ostrya/Carpinus and elm Ulmus. However, this ecosystem transition was reversible, as Picea re-established at lower abundances during the Younger Dryas. At the other three sites, there was no statistical relationship between charcoal accumulation and vegetation composition change rates, though fire frequency was a significant predictor of rates of vegetation change at Appleman Lake and Triangle Lake Bog. At these sites, Picea declined gradually over several thousand years, was replaced by deciduous hardwoods and high levels of Pinus and did not re-establish during the Younger Dryas. Synthesis. Fire does not appear to have been necessary for the climate-driven loss of Picea woodlands during the last deglaciation, but increased fire frequency accelerated the decline of Picea in some areas by clearing the way for thermophilous deciduous hardwood taxa. Hence, warming and intensified fire regimes likely interacted in the past to cause abrupt losses of coniferous forests and could again in the coming decades.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}