@article{doughty_keany_wiebe_rey-sanchez_carter_middleby_cheesman_goulden_rocha_miller_et al._2023, title={Tropical forests are approaching critical temperature thresholds}, volume={8}, ISSN={["1476-4687"]}, DOI={10.1038/s41586-023-06391}, journal={NATURE}, author={Doughty, Christopher E. and Keany, Jenna M. and Wiebe, Benjamin C. and Rey-Sanchez, Camilo and Carter, Kelsey R. and Middleby, Kali B. and Cheesman, Alexander W. and Goulden, Michael L. and Rocha, Humberto R. and Miller, Scott D. and et al.}, year={2023}, month={Aug} }
 @article{doughty_keany_wiebe_rey-sanchez_carter_middleby_cheesman_goulden_rocha_miller_et al._2023, title={Tropical forests are approaching critical temperature thresholds}, volume={8}, ISSN={["1476-4687"]}, DOI={10.1038/s41586-023-06391-z}, journal={NATURE}, author={Doughty, Christopher E. and Keany, Jenna M. and Wiebe, Benjamin C. and Rey-Sanchez, Camilo and Carter, Kelsey R. and Middleby, Kali B. and Cheesman, Alexander W. and Goulden, Michael L. and Rocha, Humberto R. and Miller, Scott D. and et al.}, year={2023}, month={Aug} }
 @article{baldocchi_keeney_rey-sanchez_fisher_2022, title={Atmospheric humidity deficits tell us how soil moisture deficits down-regulate ecosystem evaporation}, volume={159}, ISSN={0309-1708}, url={http://dx.doi.org/10.1016/j.advwatres.2021.104100}, DOI={10.1016/j.advwatres.2021.104100}, abstractNote={Knowing how actual evaporation is down-regulated from potential evaporation during periods with soil moisture deficits is one of the greatest challenges towards computing evaporation everywhere on a regular basis. We propose the hypothesis that vegetated landscapes transmit information on soil moisture deficits through its down-regulation of evaporation, which in turn affects the humidification and growth of the planetary boundary layer. To test this hypothesis, we examined how the evaporative fraction, defined as the ratio between actual and potential evaporation, corresponds with the soil moisture stress index, defined as the relative humidity with a power law dependence on vapor pressure deficit times a parameter, β. We tested the parameterized soil moisture stress index with direct eddy covariance measurements of actual evaporation and computations of potential evaporation based on meteorological conditions, averaged on monthly time steps. The analysis was conducted on a dataset obtained from 144 FLUXNET sites. These sites spanned much of the world's climates and biomes and contained over 5900 months of observations. Observations of the evaporative fraction fit the model of the soil moisture stress index best for semi-arid and arid ecosystems, and least for the humid and wet ecosystems. Consequently, a significant relationship between measurements of the evaporative fraction and soil moisture stress index held for about one-half of the population of sites. Under this condition, the median value of the parameter, β, was 1.41. To investigate the mechanism of this empirical soil moisture stress index, we diagnosed it with a coupled evaporation-planetary boundary layer model. The soil moisture stress index is strongly related to surface resistance, as defined by inverting Penman-Monteith equation. Consequently, this index provides an independent estimate of surface resistance based on easy to measure mean monthly weather conditions like relative humidity and temperature. Thereby, this soil moisture stress index has potential to be applied to weather, climate and biogeochemical models and the interpretation of satellite derived evaporation products, like the one provided by the ECOSTRESS mission.}, journal={Advances in Water Resources}, publisher={Elsevier BV}, author={Baldocchi, Dennis D. and Keeney, Nicole and Rey-Sanchez, Camilo and Fisher, Joshua B.}, year={2022}, month={Jan}, pages={104100} }
 @article{rey‐sanchez_arias‐ortiz_kasak_chu_szutu_verfaillie_baldocchi_2022, title={Detecting Hot Spots of Methane Flux Using Footprint‐Weighted Flux Maps}, volume={127}, ISSN={2169-8953 2169-8961}, url={http://dx.doi.org/10.1029/2022JG006977}, DOI={10.1029/2022JG006977}, abstractNote={Abstract}, number={8}, journal={Journal of Geophysical Research: Biogeosciences}, publisher={American Geophysical Union (AGU)}, author={Rey‐Sanchez, Camilo and Arias‐Ortiz, Ariane and Kasak, Kuno and Chu, Housen and Szutu, Daphne and Verfaillie, Joseph and Baldocchi, Dennis}, year={2022}, month={Aug} }
 @article{kong_ryu_liu_dechant_rey-sanchez_shortt_szutu_verfaillie_houborg_baldocchi_2022, title={Matching high resolution satellite data and flux tower footprints improves their agreement in photosynthesis estimates}, volume={316}, ISSN={0168-1923}, url={http://dx.doi.org/10.1016/j.agrformet.2022.108878}, DOI={10.1016/j.agrformet.2022.108878}, abstractNote={Mapping canopy photosynthesis in both high spatial and temporal resolution is essential for carbon cycle monitoring in heterogeneous areas. However, well established satellites in sun-synchronous orbits such as Sentinel-2, Landsat and MODIS can only provide either high spatial or high temporal resolution but not both. Recently established CubeSat satellite constellations have created an opportunity to overcome this resolution trade-off. In particular, Planet Fusion allows full utilization of the CubeSat data resolution and coverage while maintaining high radiometric quality. In this study, we used the Planet Fusion surface reflectance product to calculate daily, 3-m resolution, gap-free maps of the near-infrared radiation reflected from vegetation (NIRvP). We then evaluated the performance of these NIRvP maps for estimating canopy photosynthesis by comparing with data from a flux tower network in Sacramento-San Joaquin Delta, California, USA. Overall, NIRvP maps captured temporal variations in canopy photosynthesis of individual sites, despite changes in water extent in the wetlands and frequent mowing in the crop fields. When combining data from all sites, however, we found that robust agreement between NIRvP maps and canopy photosynthesis could only be achieved when matching NIRvP maps to the flux tower footprints. In this case of matched footprints, NIRvP maps showed considerably better performance than in situ NIRvP in estimating canopy photosynthesis both for daily sum and data around the time of satellite overpass (R2 = 0.78 vs. 0.60, for maps vs. in situ for the satellite overpass time case). This difference in performance was mostly due to the higher degree of consistency in slopes of NIRvP-canopy photosynthesis relationships across the study sites for flux tower footprint-matched maps. Our results show the importance of matching satellite observations to the flux tower footprint and demonstrate the potential of CubeSat constellation imagery to monitor canopy photosynthesis remotely at high spatio-temporal resolution.}, journal={Agricultural and Forest Meteorology}, publisher={Elsevier BV}, author={Kong, Juwon and Ryu, Youngryel and Liu, Jiangong and Dechant, Benjamin and Rey-Sanchez, Camilo and Shortt, Robert and Szutu, Daphne and Verfaillie, Joe and Houborg, Rasmus and Baldocchi, Dennis D.}, year={2022}, month={Apr}, pages={108878} }
 @article{morin_riley_grant_mekonnen_stefanik_sanchez_mulhare_villa_wrighton_bohrer_2022, title={Water level changes in Lake Erie drive 21st century CO2 and CH4 fluxes from a coastal temperate wetland}, volume={821}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2022.153087}, abstractNote={Wetland water depth influences microbial and plant communities, which can alter the above- and below-ground carbon cycling of a wetland. Wetland water depths are likely to change due to shifting precipitation patterns, which will affect projections of greenhouse gas emissions; however, these effects are rarely incorporated into wetland greenhouse gas models. Seeking to address this gap, we used a mechanistic model, ecosys, to simulate a range of water depth scenarios in a temperate wetland, and analyzed simulated predictions of carbon dioxide (CO2) and methane (CH4) fluxes over the 21st century. We tested our model using eddy covariance measurements of CO2 and CH4 fluxes collected at the Old Woman Creek National Estuarine Research Reserve (OWC) during 2015 and 2016. OWC is a lacustrine, estuarine, freshwater, mineral-soil marsh. An empirical model found that the wetland water depth is highly dependent on the water depth of the nearby Lake Erie. Future wetland surface water depths were modeled based on projection of Lake Erie's water depth using four separate NOAA projections, resulting in four wetland water-depth scenarios. Two of the four 21st century projections for Lake Erie water depths used in this study indicated that the water depth of the wetland would remain nearly steady; however, the other two indicated decreases in the wetland water depth. In our scenario where the wetland dries out, we project the wetland's climatological warming effect will decrease due to smaller CH4 fluxes to the atmosphere and larger CO2 uptake by the wetland. We also found that increased water level can lower emissions by shifting the site towards more open water areas, which have lower CH4 emissions. We found that decreased water depths would cause more widespread colonization of the wetland by macrophyte vegetation. Using an empirical relationship, we also found that further drying could result in other, non-wetland vegetation to emerge, dramatically altering soil carbon cycling. In three of our four projections, we found that in general the magnitude of CO2 and CH4 fluxes steadily increase over the next 100 years in response to higher temperatures. However, in our driest simulations, we projected a different response due to increased oxidation of soil carbon, with CH4 emissions decreasing substantially from an annual cumulative peak of 224.6 to a minimum of 104.7 gC m-2 year-1. In that same simulation, net cumulative flux of CO2 changed from being a sink of 56.5 gC m-2 year-1 to a source of 369.6 gC m-2 year-1 over the same period, despite a temperature increase from 13.7 °C to 14.2 °C. This temperature shift in our other three cases with greater water depths increased the source strength of CH4 and the sink strength of CO2. We conclude that the magnitude of wetland greenhouse-gas fluxes depended on the water depth primarily as it affected the areal percentage of the wetland available for plant colonization, but dramatic decreases in water depths could cause significant reductions in the wetland CH4 fluxes, while simultaneously altering the wetland vegetation.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Morin, Timothy H. and Riley, William J. and Grant, Robert F. and Mekonnen, Zelalem and Stefanik, Kay C. and Sanchez, A. Camilo Rey and Mulhare, Molly A. and Villa, Jorge and Wrighton, Kelly and Bohrer, Gil}, year={2022}, month={May} }
 @article{rey‐sanchez_wharton_vilà‐guerau de arellano_paw u_hemes_fuentes_osuna_szutu_ribeiro_verfaillie_et al._2021, title={Evaluation of Atmospheric Boundary Layer Height From Wind Profiling Radar and Slab Models and Its Responses to Seasonality of Land Cover, Subsidence, and Advection}, volume={126}, ISSN={2169-897X 2169-8996}, url={http://dx.doi.org/10.1029/2020JD033775}, DOI={10.1029/2020JD033775}, abstractNote={Abstract}, number={7}, journal={Journal of Geophysical Research: Atmospheres}, publisher={American Geophysical Union (AGU)}, author={Rey‐Sanchez, Camilo and Wharton, Sonia and Vilà‐Guerau de Arellano, Jordi and Paw U, Kyaw Tha and Hemes, Kyle S. and Fuentes, Jose D. and Osuna, Jessica and Szutu, Daphne and Ribeiro, João Vinicius and Verfaillie, Joseph and et al.}, year={2021}, month={Mar} }
 @misc{delwiche_knox_malhotra_fluet-chouinard_mcnicol_feron_ouyang_papale_trotta_canfora_et al._2021, title={FLUXNET-CH4: A global, multi-ecosystem dataset and analysis 
of methane seasonality from freshwater wetlands}, url={http://dx.doi.org/10.5194/essd-2020-307}, DOI={10.5194/essd-2020-307}, abstractNote={Abstract. Methane (CH4) emissions from natural landscapes constitute roughly half of global CH4 contributions to the atmosphere, yet large uncertainties remain in the absolute magnitude and the seasonality of emission quantities and drivers. Eddy covariance (EC) measurements of CH4 flux are ideal for constraining ecosystem-scale CH4 emissions, including their seasonality, due to quasi-continuous and high temporal resolution of flux measurements, coincident measurements of carbon, water, and energy fluxes, lack of ecosystem disturbance, and increased availability of datasets over the last decade. Here, we 1) describe the newly published dataset, FLUXNET-CH4 Version 1.0, the first global dataset of CH4 EC measurements (available at https://fluxnet.org/data/fluxnet-ch4- community-product/). FLUXNET-CH4 includes half-hourly and daily gap-filled and non gap-filled aggregated CH4 fluxes and meteorological data from 79 sites globally: 42 freshwater wetlands, 6 brackish and saline wetlands, 7 formerly drained ecosystems, 7 rice paddy sites, 2 lakes, and 15 uplands. Then, we 2) evaluate FLUXNET-CH4 representativeness for freshwater wetland coverage globally, because the majority of sites in FLUXNET-CH4 Version 1.0 are freshwater wetlands and because freshwater wetlands are a substantial source of total atmospheric CH4 emissions; and 3) provide the first global estimates of the seasonal variability and seasonality predictors of freshwater wetland CH4 fluxes. Our representativeness analysis suggests that the freshwater wetland sites in the dataset cover global wetland bioclimatic attributes (encompassing energy, moisture, and vegetation-related parameters) in arctic, boreal, and temperate regions, but only sparsely cover humid tropical regions. Seasonality metrics of wetland CH4 emissions vary considerably across latitudinal bands. In freshwater wetlands (except those between 20° S to 20° N) the spring onset of elevated CH4 emissions starts three days earlier, and the CH4 emission season lasts 4 days longer, for each degree C increase in mean annual air temperature. On average, the onset of increasing CH4 emissions lags soil warming by one month, with very few sites experiencing increased CH4 emissions prior to the onset of soil warming. In contrast, roughly half of these sites experience the spring onset of rising CH4 emissions prior to the spring increase in gross primary productivity (GPP). The timing of peak summer CH4 emissions does not correlate with the timing for either peak summer temperature or peak GPP. Our results provide seasonality parameters for CH4 modeling, and highlight seasonality metrics that cannot be predicted by temperature or GPP (i.e., seasonality of CH4 peak). The FLUXNET-CH4 dataset provides an open-access resource for CH4 flux synthesis, has a range of applications, and is unique in that it includes coupled measurements of important CH4 drivers such as GPP and temperature. Although FLUXNET-CH4 could certainly be improved by adding more sites in tropical ecosystems and by increasing the number of site-years at existing sites, it is a powerful new resource for diagnosing and understanding the role of terrestrial ecosystems and climate drivers in the global CH4 cycle. All seasonality parameters are available at https://doi.org/10.5281/zenodo.4408468. Additionally, raw FLUXNET-CH4 data used to extract seasonality parameters can be downloaded from https://fluxnet.org/data/fluxnet-ch4-community-product/, and a complete list of the 79 individual site data DOIs is provided in Table 2 in the Data Availability section of this document.
                        }, publisher={Copernicus GmbH}, author={Delwiche, Kyle B. and Knox, Sara Helen and Malhotra, Avni and Fluet-Chouinard, Etienne and McNicol, Gavin and Feron, Sarah and Ouyang, Zutao and Papale, Dario and Trotta, Carlo and Canfora, Eleonora and et al.}, year={2021}, month={Jan} }
 @article{delwiche_knox_malhotra_fluet-chouinard_mcnicol_feron_ouyang_papale_trotta_canfora_et al._2021, title={FLUXNET-CH4: a global, multi-ecosystem dataset and analysis of methane seasonality from freshwater wetlands}, volume={13}, ISSN={["1866-3516"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85111811543&partnerID=MN8TOARS}, DOI={10.5194/essd-13-3607-2021}, abstractNote={Abstract. Methane (CH4) emissions from natural landscapes constitute
roughly half of global CH4 contributions to the atmosphere, yet large
uncertainties remain in the absolute magnitude and the seasonality of
emission quantities and drivers. Eddy covariance (EC) measurements of
CH4 flux are ideal for constraining ecosystem-scale CH4
emissions due to quasi-continuous and high-temporal-resolution CH4
flux measurements, coincident carbon dioxide, water, and energy flux
measurements, lack of ecosystem disturbance, and increased availability of
datasets over the last decade. Here, we (1) describe the newly published
dataset, FLUXNET-CH4 Version 1.0, the first open-source global dataset of
CH4 EC measurements (available at
https://fluxnet.org/data/fluxnet-ch4-community-product/, last access: 7 April 2021). FLUXNET-CH4
includes half-hourly and daily gap-filled and non-gap-filled aggregated
CH4 fluxes and meteorological data from 79 sites globally: 42
freshwater wetlands, 6 brackish and saline wetlands, 7 formerly drained
ecosystems, 7 rice paddy sites, 2 lakes, and 15 uplands. Then, we (2) evaluate FLUXNET-CH4 representativeness for freshwater wetland coverage
globally because the majority of sites in FLUXNET-CH4 Version 1.0 are
freshwater wetlands which are a substantial source of total atmospheric
CH4 emissions; and (3) we provide the first global estimates of the
seasonal variability and seasonality predictors of freshwater wetland
CH4 fluxes. Our representativeness analysis suggests that the
freshwater wetland sites in the dataset cover global wetland bioclimatic
attributes (encompassing energy, moisture, and vegetation-related
parameters) in arctic, boreal, and temperate regions but only sparsely
cover humid tropical regions. Seasonality metrics of wetland CH4
emissions vary considerably across latitudinal bands. In freshwater wetlands
(except those between 20∘ S to 20∘ N) the spring onset
of elevated CH4 emissions starts 3 d earlier, and the CH4
emission season lasts 4 d longer, for each degree Celsius increase in mean
annual air temperature. On average, the spring onset of increasing CH4
emissions lags behind soil warming by 1 month, with very few sites experiencing
increased CH4 emissions prior to the onset of soil warming. In
contrast, roughly half of these sites experience the spring onset of rising
CH4 emissions prior to the spring increase in gross primary
productivity (GPP). The timing of peak summer CH4 emissions does not
correlate with the timing for either peak summer temperature or peak GPP.
Our results provide seasonality parameters for CH4 modeling and
highlight seasonality metrics that cannot be predicted by temperature or GPP
(i.e., seasonality of CH4 peak). FLUXNET-CH4 is a powerful new resource
for diagnosing and understanding the role of terrestrial ecosystems and
climate drivers in the global CH4 cycle, and future additions of sites
in tropical ecosystems and site years of data collection will provide added
value to this database. All seasonality parameters are available at
https://doi.org/10.5281/zenodo.4672601 (Delwiche et al., 2021).
Additionally, raw FLUXNET-CH4 data used to extract seasonality parameters
can be downloaded from https://fluxnet.org/data/fluxnet-ch4-community-product/ (last access: 7 April 2021), and a complete
list of the 79 individual site data DOIs is provided in Table 2 of this paper.
                    }, number={7}, journal={EARTH SYSTEM SCIENCE DATA}, author={Delwiche, Kyle B. and Knox, Sara Helen and Malhotra, Avni and Fluet-Chouinard, Etienne and McNicol, Gavin and Feron, Sarah and Ouyang, Zutao and Papale, Dario and Trotta, Carlo and Canfora, Eleonora and et al.}, year={2021}, month={Jul}, pages={3607–3689} }
 @article{irvin_zhou_mcnicol_lu_liu_fluet-chouinard_ouyang_knox_lucas-moffat_trotta_et al._2021, title={Gap-filling eddy covariance methane fluxes: Comparison of machine learning model predictions and uncertainties at FLUXNET-CH4 wetlands}, volume={308-309}, ISSN={0168-1923}, url={http://dx.doi.org/10.1016/j.agrformet.2021.108528}, DOI={10.1016/j.agrformet.2021.108528}, abstractNote={Time series of wetland methane fluxes measured by eddy covariance require gap-filling to estimate daily, seasonal, and annual emissions. Gap-filling methane fluxes is challenging because of high variability and complex responses to multiple drivers. To date, there is no widely established gap-filling standard for wetland methane fluxes, with regards both to the best model algorithms and predictors. This study synthesizes results of different gap-filling methods systematically applied at 17 wetland sites spanning boreal to tropical regions and including all major wetland classes and two rice paddies. Procedures are proposed for: 1) creating realistic artificial gap scenarios, 2) training and evaluating gap-filling models without overstating performance, and 3) predicting half-hourly methane fluxes and annual emissions with realistic uncertainty estimates. Performance is compared between a conventional method (marginal distribution sampling) and four machine learning algorithms. The conventional method achieved similar median performance as the machine learning models but was worse than the best machine learning models and relatively insensitive to predictor choices. Of the machine learning models, decision tree algorithms performed the best in cross-validation experiments, even with a baseline predictor set, and artificial neural networks showed comparable performance when using all predictors. Soil temperature was frequently the most important predictor whilst water table depth was important at sites with substantial water table fluctuations, highlighting the value of data on wetland soil conditions. Raw gap-filling uncertainties from the machine learning models were underestimated and we propose a method to calibrate uncertainties to observations. The python code for model development, evaluation, and uncertainty estimation is publicly available. This study outlines a modular and robust machine learning workflow and makes recommendations for, and evaluates an improved baseline of, methane gap-filling models that can be implemented in multi-site syntheses or standardized products from regional and global flux networks (e.g., FLUXNET).}, journal={Agricultural and Forest Meteorology}, publisher={Elsevier BV}, author={Irvin, Jeremy and Zhou, Sharon and McNicol, Gavin and Lu, Fred and Liu, Vincent and Fluet-Chouinard, Etienne and Ouyang, Zutao and Knox, Sara Helen and Lucas-Moffat, Antje and Trotta, Carlo and et al.}, year={2021}, month={Oct}, pages={108528} }
 @article{helbig_gerken_beamesderfer_baldocchi_banerjee_biraud_brown_brunsell_burakowski_burns_et al._2021, title={Integrating continuous atmospheric boundary layer and tower-based flux measurements to advance understanding of land-atmosphere interactions}, volume={307}, ISSN={0168-1923}, url={http://dx.doi.org/10.1016/j.agrformet.2021.108509}, DOI={10.1016/j.agrformet.2021.108509}, abstractNote={The atmospheric boundary layer mediates the exchange of energy, matter, and momentum between the land surface and the free troposphere, integrating a range of physical, chemical, and biological processes and is defined as the lowest layer of the atmosphere (ranging from a few meters to 3 km). In this review, we investigate how continuous, automated observations of the atmospheric boundary layer can enhance the scientific value of co-located eddy covariance measurements of land-atmosphere fluxes of carbon, water, and energy, as are being made at FLUXNET sites worldwide. We highlight four key opportunities to integrate tower-based flux measurements with continuous, long-term atmospheric boundary layer measurements: (1) to interpret surface flux and atmospheric boundary layer exchange dynamics and feedbacks at flux tower sites, (2) to support flux footprint modelling, the interpretation of surface fluxes in heterogeneous and mountainous terrain, and quality control of eddy covariance flux measurements, (3) to support regional-scale modeling and upscaling of surface fluxes to continental scales, and (4) to quantify land-atmosphere coupling and validate its representation in Earth system models. Adding a suite of atmospheric boundary layer measurements to eddy covariance flux tower sites, and supporting the sharing of these data to tower networks, would allow the Earth science community to address new emerging research questions, better interpret ongoing flux tower measurements, and would present novel opportunities for collaborations between FLUXNET scientists and atmospheric and remote sensing scientists.}, journal={Agricultural and Forest Meteorology}, publisher={Elsevier BV}, author={Helbig, Manuel and Gerken, Tobias and Beamesderfer, Eric R. and Baldocchi, Dennis D. and Banerjee, Tirtha and Biraud, Sébastien C. and Brown, William O.J. and Brunsell, Nathaniel A. and Burakowski, Elizabeth A and Burns, Sean P. and et al.}, year={2021}, month={Sep}, pages={108509} }
 @article{anderson_yang_xue_knipper_yang_gao_hain_kustas_cawse-nicholson_hulley_et al._2021, title={Interoperability of ECOSTRESS and Landsat for mapping evapotranspiration time series at sub-field scales}, volume={252}, ISSN={0034-4257}, url={http://dx.doi.org/10.1016/j.rse.2020.112189}, DOI={10.1016/j.rse.2020.112189}, abstractNote={Land-surface temperature retrieved from thermal infrared (TIR) remote sensing has proven to be a valuable constraint in surface energy balance models for estimating evapotranspiration (ET). For optimal utility in agricultural water management applications, frequent thermal imaging (<4-day revisit) at sub-field (100 m or less) spatial resolution is desired. While, the current suite of Landsat satellites (7 and 8) provides the required spatial resolution, the 8-day combined revisit can be inadequate to capture rapid changes in surface moisture status or crop phenology, particularly in areas of persistent cloud cover. The new ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) mission, with an average 4-day revisit interval and nominal 70-m resolution, provides a valuable research platform for augmenting Landsat TIR sampling and for investigating TIR-based ET mapping mission requirements more broadly. This study investigates the interoperability of Landsat and ECOSTRESS imaging for developing ET image timeseries with high spatial (30-m) and temporal (daily) resolution. A data fusion algorithm is used to fuse Landsat and ECOSTRESS ET retrievals at 30 m with daily 500-m retrievals using TIR data from the Moderate Resolution Imaging Spectroradiometer (MODIS) over target agricultural sites spanning the United States.The added value of the combined multi-source dataset is quantified in comparison with daily flux tower observations collected within these target domains. In addition, we investigate ET model performance as a function of ECOSTRESS view angle, overpass time, and time separation between TIR and Landsat visible to shortwave infrared (VSWIR) data acquisitions used to generate land-surface temperature, leaf area index, and albedo inputs to the surface energy balance model. The results demonstrate the value of the higher temporal sampling provided by ECOSTRESS, especially in areas that are frequently impacted by cloud cover. Limiting usage to ECOSTRESS scenes collected between 9:00 a.m. to 5:00 p.m. and nadir viewing angles <20° yielded daily (24-h) ET retrievals of comparable quality to the well-tested Landsat baseline. We also discuss challenges in using land-surface temperature from a thermal free-flyer system for ET retrieval, which may have ramifications for future TIR water-use mapping missions.}, journal={Remote Sensing of Environment}, publisher={Elsevier BV}, author={Anderson, Martha C. and Yang, Yang and Xue, Jie and Knipper, Kyle R. and Yang, Yun and Gao, Feng and Hain, Chris R. and Kustas, William P. and Cawse-Nicholson, Kerry and Hulley, Glynn and et al.}, year={2021}, month={Jan}, pages={112189} }
 @article{kasak_valach_rey-sanchez_kill_shortt_liu_dronova_mander_szutu_verfaillie_et al._2020, title={Experimental harvesting of wetland plants to evaluate trade-offs between reducing methane emissions and removing nutrients accumulated to the biomass in constructed wetlands}, volume={715}, ISSN={0048-9697}, url={http://dx.doi.org/10.1016/j.scitotenv.2020.136960}, DOI={10.1016/j.scitotenv.2020.136960}, abstractNote={Constructed wetlands built for water treatment often need biomass harvesting to remove nutrients from the system. Usually harvesting is done during the peak growing season to maximize the amount of nutrients removed from the system. This, however, can create huge methane fluxes that escape from plant tissues to the atmosphere. We used manual chambers and eddy covariance measurements to analyze the increase in methane emissions due to the harvesting of two common wetland species, Typha spp. and Schoenoplectus spp., in two climatically different constructed wetlands in Estonia and California. In addition, we determined the biomass nutrient and carbon concentrations from harvested biomass. We found that harvesting during the summer season, e.g. June and August, resulted in a significant release of methane at both sites. At the California site, baseline median methane emissions were 217.6 nmol m−2 s−1, and harvesting resulted in increases to 395.4 nmol m−2 s−1 that decreased to baseline emission within three days. Footprint modeling demonstrated that the emission increases measured by eddy covariance were dominated by contributions from the cut area to the total footprint signal. At the Estonian site, harvesting resulted in methane increases of 15.9 nmol m−2 s−1 to 110.4 nmol m−2 s−1 in August. However, in September and October the emission was significantly lower. Plant biomass analyses showed clear temporal dynamics in terms of nutrient concentration, being highest in summer and lowest in winter. Our experiments indicate that the optimal time for aboveground biomass harvesting is at the end of the growing season before nutrient translocation to belowground plant structures begins coinciding with lowest methane emissions. Therefore, strategic planning of the harvest timing may help reduce greenhouse gas emissions from managed wetlands and thus improve their multi-faceted ecological benefit.}, journal={Science of The Total Environment}, publisher={Elsevier BV}, author={Kasak, K. and Valach, A.C. and Rey-Sanchez, C. and Kill, K. and Shortt, R. and Liu, J. and Dronova, I. and Mander, Ü. and Szutu, D. and Verfaillie, J. and et al.}, year={2020}, month={May}, pages={136960} }
 @article{liu_zhou_valach_shortt_kasak_rey‐sanchez_hemes_baldocchi_lai_2020, title={Methane emissions reduce the radiative cooling effect of a subtropical estuarine mangrove wetland by half}, volume={26}, ISSN={1354-1013 1365-2486}, url={http://dx.doi.org/10.1111/gcb.15247}, DOI={10.1111/gcb.15247}, abstractNote={Abstract}, number={9}, journal={Global Change Biology}, publisher={Wiley}, author={Liu, Jiangong and Zhou, Yulun and Valach, Alex and Shortt, Robert and Kasak, Kuno and Rey‐Sanchez, Camilo and Hemes, Kyle S. and Baldocchi, Dennis and Lai, Derrick Y. F.}, year={2020}, month={Jul}, pages={4998–5016} }
 @article{baldocchi_ryu_dechant_eichelmann_hemes_ma_sanchez_shortt_szutu_valach_et al._2020, title={Outgoing Near‐Infrared Radiation From Vegetation Scales With Canopy Photosynthesis Across a Spectrum of Function, Structure, Physiological Capacity, and Weather}, volume={125}, ISSN={2169-8953 2169-8961}, url={http://dx.doi.org/10.1029/2019JG005534}, DOI={10.1029/2019JG005534}, abstractNote={Abstract}, number={7}, journal={Journal of Geophysical Research: Biogeosciences}, publisher={American Geophysical Union (AGU)}, author={Baldocchi, Dennis D. and Ryu, Youngryel and Dechant, Benjamin and Eichelmann, Elke and Hemes, Kyle and Ma, Siyan and Sanchez, Camilo Rey and Shortt, Robert and Szutu, Daphne and Valach, Alex and et al.}, year={2020}, month={Jul} }
 @article{villa_ju_stephen_rey‐sanchez_wrighton_bohrer_2020, title={Plant‐mediated methane transport in emergent and floating‐leaved species of a temperate freshwater mineral‐soil wetland}, volume={65}, ISSN={0024-3590 1939-5590}, url={http://dx.doi.org/10.1002/lno.11467}, DOI={10.1002/lno.11467}, abstractNote={Abstract}, number={7}, journal={Limnology and Oceanography}, publisher={Wiley}, author={Villa, Jorge A. and Ju, Yang and Stephen, Taylor and Rey‐Sanchez, Camilo and Wrighton, Kelly C. and Bohrer, Gil}, year={2020}, month={Jun}, pages={1635–1650} }
 @article{russell_vines_bohrer_johnson_villa_heltzel_rey-sanchez_matthes_2020, title={Quantifying CH4 concentration spikes above baseline and attributing CH4 sources to hydraulic fracturing activities by continuous monitoring at an off-site tower}, volume={228}, ISSN={1352-2310}, url={http://dx.doi.org/10.1016/j.atmosenv.2020.117452}, DOI={10.1016/j.atmosenv.2020.117452}, abstractNote={Hydraulic fracturing (hydrofracking) for natural gas has increased rapidly in the area of the Marcellus Shale in the last thirty years and estimates of CH4 emissions from hydrofracking operations are still uncertain. Previous studies on CH4 emissions at hydrofracking operations have used bottom-up approaches collected at discrete timepoints or discrete aerial surveys covering a wide spatial area, constraining the temporal scale of inference regarding these emissions. This project monitored atmospheric CH4 concentrations and stable carbon isotopes at a half-hourly temporal resolution from a 20-m tower downwind of a hydrofracking well pad in West Virginia for eighteen months. We collected four months of baseline observations prior to onsite well development to construct an empirical artificial neural-network model of baseline CH4 concentrations. We compared measured CH4 concentrations against the ANN-modeled CH4 baseline to identify CH4 concentration spikes that coincided with different stages of onsite well development, from the baseline period through fracking. CH4 concentration spikes were significantly more frequent than baseline conditions during the vertical drilling and fracking phases of operations. We found that the median magnitude of CH4 concentration spikes during the vertical drilling phase was 316% larger than that of the baseline phase, and the median magnitude of CH4 concentration spikes was 509% larger in the hydraulic stimulation (fracking) stage compared to the baseline phase. We also partitioned the sources of measured CH4 concentrations to biogenic ruminant and geologic shale gas isotopic signatures by measuring 13CH4 gas at high temporal resolution and using a source-partitioning 13CH4 model. The measured median value of half-hourly CH4 concentration spikes attributed to a geologic shale gas isotopic origin was 27% larger than the median CH4 concentration spikes attributed to ruminants, and the maximum half-hourly CH4 concentration spike attributed to shale gas was up to 179% higher than maximum CH4 concentration spike for ruminant-dominated half-hours. This study developed a framework for off-site, single tower measurements to identify CH4 concentration spikes associated with the phases of unconventional natural gas well development in a complex CH4 emissions airshed.}, journal={Atmospheric Environment}, publisher={Elsevier BV}, author={Russell, Sarah J. and Vines, Chante’ D. and Bohrer, Gil and Johnson, Derek R. and Villa, Jorge A. and Heltzel, Robert and Rey-Sanchez, Camilo and Matthes, Jaclyn H.}, year={2020}, month={May}, pages={117452} }
 @article{ma_eichelmann_wolf_rey-sanchez_baldocchi_2020, title={Transpiration and evaporation in a Californian oak-grass savanna: Field measurements and partitioning model results}, volume={295}, ISSN={0168-1923}, url={http://dx.doi.org/10.1016/j.agrformet.2020.108204}, DOI={10.1016/j.agrformet.2020.108204}, abstractNote={As the eddy-covariance technique enables intensive measurements of evapotranspiration (ET) at the ecosystem level, the interest in further partitioning ET into two main process-based components transpiration (T) and surface evaporation (E) □ is increasing. Although models for partitioning tower-measured ET have been developed, their reliability for different types of ecosystems still requires extensive validations. From 2001 to 2019, we measured CO2 and H2O vapor fluxes over an oak-grass savanna landscape from three eddy-covariance towers (i.e., one over an oak woodland; the other two over annual grasslands under tree canopy and in open area). Annual ET (± standard deviation) from the oak woodland, understory grassland, and open grassland was 419±85 mm, 167±36 mm, 324±43 mm, respectively. The differences between the above- and below-canopy ET indicated that oak canopy transpiration (Toak) was 281±48 mm year−1, accounting for 67±8% of the total ET of the woodland. The Toak/ET ratio varied in seasons, similar to the pattern of oak's leaf area index but opposite to that of soil moisture. We then tested two ET-partitioning models: Scott's long-term-regression-interception (LTRI) model (Scott and Biederman, 2017) and Zhou's quantile-regression-maximum-slope (QRMS) model (Zhou et al., 2016). Even though we expected that the two models would give divergent results since theiremo working principles, both models captured reasonable magnitudes and seasonal patterns of the T/ET ratio, as suggested by tower measurements. The study confirms that the LTRI and QRMS models are applicable for savanna ecosystems, but some modifications are necessary for tree dominated areas. In combination with field and modeling approaches, this study improves our understanding on the contributions of transpiration and evaporation to total ET from ecosystems with vertical vegetation layers.}, journal={Agricultural and Forest Meteorology}, publisher={Elsevier BV}, author={Ma, Siyan and Eichelmann, Elke and Wolf, Sebastian and Rey-Sanchez, Camilo and Baldocchi, Dennis D.}, year={2020}, month={Dec}, pages={108204} }
 @article{grau-andrés_davies_rey-sanchez_slater_2019, place={DE}, title={Bryophyte community composition and diversity are indicators of hydrochemical and ecological gradients in temperate kettle hole mires in Ohio, USA}, volume={24}, ISSN={1819-754X}, url={https://doi.org/10.19189/MaP.2019.APG.StA.1783}, DOI={10.19189/MaP.2019.APG.StA.1783}, abstractNote={The Ohio Agricultural Research and Development Center of The Ohio State University (SEEDS grant)}, number={24}, journal={Mires and Peat}, publisher={International Mire Conservation Group and International Peatland Society}, author={Grau-Andrés, R. and Davies, G.M. and Rey-Sanchez, C. and Slater, J.}, year={2019}, month={Dec}, pages={1–15} }
 @article{rey-sanchez_posada_2019, title={Effect of temporally heterogeneous light on photosynthetic light use efficiency, plant acclimation and growth in Abatia parviflora}, volume={46}, ISSN={1445-4408}, url={http://dx.doi.org/10.1071/FP18279}, DOI={10.1071/FP18279}, abstractNote={
Individual leaves have a unique instantaneous photosynthetic photon flux density (PPFD) at which net photosynthetic light use efficiency (ϵL, the ratio between net photosynthesis and PPFD) is maximised (PPFDϵmax). When PPFD is above or below PPFDϵmax, efficiency declines. Thus, we hypothesised that heterogeneous PPFD conditions should increase the amount of time leaves photosynthesise at a PPFD different than PPFDϵmax and result in reduced growth. To date, this prediction has not been rigorously tested. Here, we exposed seedlings of Abatia parviflora Ruiz & Pav to light regimes of equal total daily irradiance but with three different daily time courses of PPFD: constant PPFD (No_H), low heterogeneity (Low_H) and high heterogeneity (High_H). Mean ϵL, leaf daily photosynthesis and plant growth were all significantly higher in No_H and Low_H plants than in High_H plants, supporting our hypothesis. In addition, mean ϵL was positively related to final plant biomass. Unexpectedly, High_H plants had more etiolated stems and more horizontal leaves than No_H and Low_H plants, possibly due to exposure to low PPFD in the morning and afternoon. In conclusion, PPFD heterogeneity had an important effect on average ϵL, photosynthesis and growth, but also on allocation and plant morphology.
}, number={7}, journal={Functional Plant Biology}, publisher={CSIRO Publishing}, author={Rey-Sanchez, Camilo and Posada, Juan M.}, year={2019}, pages={684} }
 @article{villa_ju_vines_rey-sanchez_morin_wrighton_bohrer_2019, title={Relationships Between Methane and Carbon Dioxide Fluxes in a Temperate Cattail-Dominated Freshwater Wetland}, volume={124}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85069834504&partnerID=MN8TOARS}, DOI={10.1029/2019JG005167}, abstractNote={Abstract}, number={7}, journal={Journal of Geophysical Research: Biogeosciences}, author={Villa, J.A. and Ju, Y. and Vines, C. and Rey-Sanchez, C. and Morin, T.H. and Wrighton, K.C. and Bohrer, G.}, year={2019}, pages={2076–2089} }
 @article{sanchez_2019, title={Reply to reviewer 1}, volume={7}, url={https://doi.org/10.5194/bg-2019-116-AC1}, DOI={10.5194/bg-2019-116-AC1}, publisher={Copernicus GmbH}, author={Sanchez, Camilo Rey}, year={2019}, month={Jul} }
 @article{sanchez_2019, title={Response to reviewer 2}, volume={7}, url={https://doi.org/10.5194/bg-2019-116-AC2}, DOI={10.5194/bg-2019-116-AC2}, publisher={Copernicus GmbH}, author={Sanchez, Camilo Rey}, year={2019}, month={Jul} }
 @article{xiao_li_he_arain_beringer_desai_emmel_hollinger_krasnova_mammarella_et al._2019, title={Solar-induced chlorophyll fluorescence exhibits a universal relationship with gross primary productivity across a wide variety of biomes}, volume={25}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85060650515&partnerID=MN8TOARS}, DOI={10.1111/gcb.14565}, abstractNote={In our recent study in Global Change Biology (Li et al., ), we examined the relationship between solar-induced chlorophyll fluorescence (SIF) measured from the Orbiting Carbon Observatory-2 (OCO-2) and gross primary productivity (GPP) derived from eddy covariance flux towers across the globe, and we discovered that there is a nearly universal relationship between SIF and GPP across a wide variety of biomes. This finding reveals the tremendous potential of SIF for accurately mapping terrestrial photosynthesis globally.}, number={4}, journal={Global Change Biology}, author={Xiao, J. and Li, X. and He, B. and Arain, M.A. and Beringer, J. and Desai, A.R. and Emmel, C. and Hollinger, D.Y. and Krasnova, A. and Mammarella, I. and et al.}, year={2019}, pages={e4–e6} }
 @article{rey-sanchez_bohrer_slater_li_grau-andrés_hao_rich_davies_2019, title={The ratio of methanogens to methanotrophs and water-level dynamics drive methane exchange velocity in a temperate kettle-hole peat bog}, volume={4}, url={https://doi.org/10.5194/bg-2019-116}, DOI={10.5194/bg-2019-116}, abstractNote={Abstract. Peatlands are a large source of methane (CH4) to the atmosphere, yet the uncertainty around the estimates of CH4 flux from peatlands is large. To better understand the spatial heterogeneity in temperate peatland CH4 emissions and their response to physical and biological drivers, we studied CH4 dynamics throughout the growing seasons of 2017 and 2018 in Flatiron Lake Bog, a kettle-hole peat bog in Ohio. The site is composed of six different hydro-biological zones: an open water zone, four concentric vegetation zones surrounding the open water, and a restored zone connected to the main bog by a narrow channel. At each of these locations, we monitored water level (WL), CH4 pore-water concentration at different peat depths, CH4 fluxes from the ground and from representative plant species using chambers, and microbial community composition with focus here on known methanogens and methanotrophs. Integrated CH4 emissions for the growing season were estimated as 315.4 ± 166 mg CH4 m−2 d−1 in 2017, and 362.3 ± 687 mg CH4 m−2 d−1 in 2018. Median CH4 emission was highest in the open water, then decreased and became more variable through the concentric vegetation zones as the WL dropped, with extreme emission hotspots observed in the Tamarack mixed woodlands (TMW), and low emissions in the restored zone (18.8–30.3 mg CH4 m−2 d−1). Generally, CH4 flux from above-ground vegetation was negligible compared to ground flux (
                        }, publisher={Copernicus GmbH}, author={Rey-Sanchez, Camilo and Bohrer, Gil and Slater, Julie and Li, Yueh-Fen and Grau-Andrés, Roger and Hao, Yushan and Rich, Virginia I. and Davies, G. Matt}, year={2019}, month={Apr} }
 @article{rey-sanchez_bohrer_slater_li_grau-andrés_hao_rich_davies_2019, title={The ratio of methanogens to methanotrophs and water-level dynamics drive methane transfer velocity in a temperate kettle-hole peat bog}, volume={16}, ISSN={1726-4189}, url={http://dx.doi.org/10.5194/bg-16-3207-2019}, DOI={10.5194/bg-16-3207-2019}, abstractNote={Abstract. Peatlands are a large source of methane (CH4) to the
atmosphere, yet the uncertainty around the estimates of CH4 flux from
peatlands is large. To better understand the spatial heterogeneity in
temperate peatland CH4 emissions and their response to physical and
biological drivers, we studied CH4 dynamics throughout the growing
seasons of 2017 and 2018 in Flatiron Lake Bog, a kettle-hole peat bog in
Ohio. The site is composed of six different hydro-biological zones: an open
water zone, four concentric vegetation zones surrounding the open water, and
a restored zone connected to the main bog by a narrow channel. At each of
these locations, we monitored water level (WL), CH4 pore-water
concentration at different peat depths, CH4 fluxes from the ground and
from representative plant species using chambers, and microbial community
composition with a focus here on known methanogens and methanotrophs.
Integrated CH4 emissions for the growing season were estimated as 315.4±166 mgCH4m-2d-1 in 2017 and 362.3±687 mgCH4m-2d-1 in 2018. Median CH4 emission was highest in
the open water, then it decreased and became more variable through the
concentric vegetation zones as the WL dropped, with extreme emission
hotspots observed in the tamarack mixed woodlands (Tamarack) and low
emissions in the restored zone (18.8–30.3 mgCH4m-2d-1).
Generally, CH4 flux from above-ground vegetation was negligible
compared to ground flux (<0.4 %), although blueberry plants were
a small CH4 sink. Pore-water CH4 concentrations varied
significantly among zones, with the highest values in the Tamarack zone,
close to saturation, and the lowest values in the restored zone. While the
CH4 fluxes and pore-water concentrations were not correlated with
methanogen relative abundance, the ratio of methanogens to methanotrophs in
the upper portion of the peat was significantly correlated to CH4
transfer velocity (the CH4 flux divided by the difference in CH4 pore-water concentration between the top of the peat profile and the
concentration in equilibrium with the atmosphere). Since ebullition and
plant-mediated transport were not important sources of CH4 and the peat
structure and porosity were similar across the different zones in the bog,
we conclude that the differences in CH4 transfer velocities, and thus
the flux, are driven by the ratio of methanogen to methanotroph relative
abundance close to the surface. This study illustrates the importance of the
interactions between water-level and microbial composition to better
understand CH4 fluxes from bogs and wetlands in general.
                    }, number={16}, journal={Biogeosciences}, publisher={Copernicus GmbH}, author={Rey-Sanchez, Camilo and Bohrer, Gil and Slater, Julie and Li, Yueh-Fen and Grau-Andrés, Roger and Hao, Yushan and Rich, Virginia I. and Davies, G. Matt}, year={2019}, month={Aug}, pages={3207–3231} }
 @article{morin_rey-sánchez_vogel_matheny_kenny_bohrer_2018, title={Carbon dioxide emissions from an oligotrophic temperate lake: An eddy covariance approach}, volume={114}, ISSN={0925-8574}, url={http://dx.doi.org/10.1016/j.ecoleng.2017.05.005}, DOI={10.1016/j.ecoleng.2017.05.005}, abstractNote={In recent years, several studies have suggested that most lakes are net carbon sources to the atmosphere rather than carbon sinks. Quantifying and understanding the environmental drivers of carbon dioxide (CO2) flux from lakes is important in order to have a better understanding of the current and future greenhouse-gas budget of aquatic systems and the global ecosystem as a whole. In this study, we present observations of CO2 fluxes in an oligotrophic lake in Northern Michigan during two full growing seasons. We used the eddy covariance technique to measure continuous fluxes of CO2 and calculate the advective fluxes between the lake and the surrounding forest. We found that, at our measurement location far from shore, to the effects of horizontal advection were significantly lower than EC-observed vertical turbulent fluxes and contributed minimally to estimate of the seasonal totals. We found that during the summers the lake was an overall net carbon source, though at rates at much lower magnitude than nearby terrestrial ecosystems. Using a hierarchical modelling approach, we determined that net carbon flux from the lake is primarily correlated with wind speed, indicating the key role of mixing in the upper water layer. Variables indicative of microbial activity and lake gas storage were more highly correlated with the positive fraction of carbon flux than with carbon uptake.}, journal={Ecological Engineering}, publisher={Elsevier BV}, author={Morin, T.H. and Rey-Sánchez, A.C. and Vogel, C.S. and Matheny, A.M. and Kenny, W.T. and Bohrer, G.}, year={2018}, month={Apr}, pages={25–33} }
 @article{rey-sanchez_morin_stefanik_wrighton_bohrer_2018, title={Determining total emissions and environmental drivers of methane flux in a Lake Erie estuarine marsh}, volume={114}, ISSN={0925-8574}, url={http://dx.doi.org/10.1016/j.ecoleng.2017.06.042}, DOI={10.1016/j.ecoleng.2017.06.042}, abstractNote={Estuarine freshwater marshes can act as an important ecosystem for carbon storage and flux because of its strategic position in a watershed. We monitored CH4 and CO2 fluxes in Old Woman Creek, an estuarine wetland of Lake Erie, Ohio. The eddy covariance (EC) technique was used to measure fluxes of CH4 and CO2 continuously during the growing seasons of 2015 and 2016. Simultaneously, monthly sampling of gas exchange was conducted using non-steady state chambers in four distinct land-cover types in the wetland: open water, emergent vegetation (Typha spp.), floating vegetation (Nelumbo spp.) and mud flats. Chambers and EC measurements were combined to provide estimates of the continuous contributions of each land cover to the total methane emissions of the wetland. In addition, water and meteorological measurements were used to determine the most important environmental drivers of methane flux in the wetland. We found an average rate of emission from the Typha patch, the most abundant vegetated land cover, of 219.4 g CH4 C m−2 y−1, which was much higher than rates reported in similar emergent vegetation types in other wetlands. Mud flats had the highest rates of CH4 emission, followed by Nelumbo and Typha patches, and open water. Mud flats contributed 6.8% of the total CH4 emissions of the wetland despite occupying only 1.5% of the wetland area, whereas open water contributed 16.1% despite occupying 47% of the wetland area. Water temperature and wind speed were the strongest environmental drivers of CH4 flux to the atmosphere. Carbon fluxes were strongly correlated to methane fluxes. Fluctuating water levels above the wetland’s surface had a weak effect on overall CH4 emissions in the wetland, with stronger effects during the night than during the day. Providing an empirical model that predicts the influence of different environmental drivers CH4 emissions in the wetland can aid in the design of estuarine wetlands that retain nutrients and reduce coastal eutrophication while minimizing greenhouse gas emissions.}, journal={Ecological Engineering}, publisher={Elsevier BV}, author={Rey-Sanchez, A.C. and Morin, T.H. and Stefanik, K.C. and Wrighton, K. and Bohrer, G.}, year={2018}, month={Apr}, pages={7–15} }
 @article{sanchez_rey-sánchez_posada_smith_2018, title={Interplay of seasonal sunlight, air and leaf temperature in two alpine páramo species, Colombian Andes}, volume={253-254}, ISSN={0168-1923}, url={http://dx.doi.org/10.1016/j.agrformet.2018.01.033}, DOI={10.1016/j.agrformet.2018.01.033}, abstractNote={Abstract In models of photosynthetic gas exchange, leaf temperature (Tleaf) is often calculated using a combination of derivations of the energy balance equation and measurements of air temperature (Tair). Yet, there are frequently large differences between Tleaf and Tair under natural field conditions, and an energy balance is complicated in complex canopies, especially in tropical ecosystems. In the present study, we aimed to quantify the variation in Tleaf relative to Tair under naturally varying PPFD values in two representative species (Espeletia grandiflora and Chusquea tessellata) of a tropical alpine ecosystem (paramo, Colombian Andes) during both wet and dry seasons. The results of a Structural Equation Model showed that Tleaf was strongly correlated with changes in Tair during both seasons, but large differences (up to 14 °C) occurred between Tair and Tleaf, during the dry season when PPFD varied the most, especially in C. tessellata. Thus, using Tair to proximate Tleaf under variable conditions of incident sunlight could generate substantial errors in estimates of temperature-sensitive physiological processes. These results should be valuable for evaluating the accuracy of carbon and water exchange models within current and future scenarios of climate change in tropical paramos, as well as other ecosystems.}, journal={Agricultural and Forest Meteorology}, publisher={Elsevier BV}, author={Sanchez, Adriana and Rey-Sánchez, A. Camilo and Posada, Juan M. and Smith, William K.}, year={2018}, month={May}, pages={38–47} }
 @article{li_xiao_he_altaf arain_beringer_desai_emmel_hollinger_krasnova_mammarella_et al._2018, title={Solar‐induced chlorophyll fluorescence is strongly correlated with terrestrial photosynthesis for a wide variety of biomes: First global analysis based on OCO‐2 and flux tower observations}, volume={24}, ISSN={1354-1013 1365-2486}, url={http://dx.doi.org/10.1111/gcb.14297}, DOI={10.1111/gcb.14297}, abstractNote={Abstract}, number={9}, journal={Global Change Biology}, publisher={Wiley}, author={Li, Xing and Xiao, Jingfeng and He, Binbin and Altaf Arain, M. and Beringer, Jason and Desai, Ankur R. and Emmel, Carmen and Hollinger, David Y. and Krasnova, Alisa and Mammarella, Ivan and et al.}, year={2018}, month={Jun}, pages={3990–4008} }
 @article{morin_bohrer_stefanik_rey-sanchez_matheny_mitsch_2017, title={Combining eddy-covariance and chamber measurements to determine the methane budget from a small, heterogeneous urban floodplain wetland park}, volume={237-238}, ISSN={0168-1923}, url={http://dx.doi.org/10.1016/j.agrformet.2017.01.022}, DOI={10.1016/j.agrformet.2017.01.022}, abstractNote={Methane (CH4) emissions and carbon uptake in temperate freshwater wetlands act in opposing directions in the context of global radiative forcing. Large uncertainties exist for the rates of CH4 emissions making it difficult to determine the extent that CH4 emissions counteract the carbon sequestration of wetlands. Urban temperate wetlands are typically small and feature highly heterogeneous land cover, posing an additional challenge to determining their CH4 budget. The data analysis approach we introduce here combines two different CH4 flux measurement techniques to overcome scale and heterogeneity problems and determine the overall CH4 budget of a small, heterogeneous, urban wetland landscape. Temporally intermittent point measurements from non-steady-state chambers provided information about patch-level heterogeneity of fluxes, while continuous, high temporal resolution flux measurements using the eddy-covariance (EC) technique provided information about the temporal dynamics of the fluxes. Patch-level scaling parameterization was developed from the chamber data to scale eddy covariance data to a ‘fixed-frame’, which corrects for variability in the spatial coverage of the eddy covariance observation footprint at any single point in time. By combining two measurement techniques at different scales, we addressed shortcomings of both techniques with respect to heterogeneous wetland sites. We determined that fluxes observed by the two methods are statistically similar in magnitude when brought to the same temporal and spatial scale. We also found that open-water and macrophyte-covered areas of the wetland followed similar phenological cycles and emitted nearly equivalent levels of CH4 for much of the year. However, vegetated wetland areas regularly exhibited a stronger late-summer emission peak, possibly due to CH4 transport through mature vegetation vascular systems. Normalizing the eddy covariance data to a fixed-frame allowed us to determine the seasonal CH4 budget of each patch and the overall site. Overall, the macrophyte areas had the largest CH4 fluxes followed by the open water areas. Uncertainties in the final CH4 budget included spatial heterogeneity of CH4 fluxes, the tower footprint, measurement in the data to be scaled, and gap-filling. Of these, the spatial placement of the chambers provided the largest source of uncertainty in CH4 estimates. This reinforces the need to utilize site-level measurements when estimating CH4 fluxes from wetlands as opposed to using only up-scaled point measurements.}, journal={Agricultural and Forest Meteorology}, publisher={Elsevier BV}, author={Morin, T.H. and Bohrer, G. and Stefanik, K.C. and Rey-Sanchez, A.C. and Matheny, A.M. and Mitsch, W.J.}, year={2017}, month={May}, pages={160–170} }
 @article{rey-sánchez_bohrer_morin_shlomo_mirfenderesgi_gildor_genin_2017, title={Evaporation and CO
            <sub>2
            fluxes in a coastal reef: an eddy covariance approach}, volume={3}, ISSN={2096-4129 2332-8878}, url={http://dx.doi.org/10.1080/20964129.2017.1392830}, DOI={10.1080/20964129.2017.1392830}, abstractNote={ABSTRACT}, number={10}, journal={Ecosystem Health and Sustainability}, publisher={American Association for the Advancement of Science (AAAS)}, author={Rey-Sánchez, A. Camilo and Bohrer, Gil and Morin, Timothy H. and Shlomo, Dekel and Mirfenderesgi, Golnazalsadat and Gildor, Hezi and Genin, Amatzia}, year={2017}, month={Oct} }
 @article{angle_morin_solden_narrowe_smith_borton_rey-sanchez_daly_mirfenderesgi_hoyt_et al._2017, title={Methanogenesis in oxygenated soils is a substantial fraction of wetland methane emissions}, volume={8}, ISSN={2041-1723}, url={http://dx.doi.org/10.1038/s41467-017-01753-4}, DOI={10.1038/s41467-017-01753-4}, abstractNote={Abstract}, number={1}, journal={Nature Communications}, publisher={Springer Science and Business Media LLC}, author={Angle, Jordan C. and Morin, Timothy H. and Solden, Lindsey M. and Narrowe, Adrienne B. and Smith, Garrett J. and Borton, Mikayla A. and Rey-Sanchez, Camilo and Daly, Rebecca A. and Mirfenderesgi, Golnazalsdat and Hoyt, David W. and et al.}, year={2017}, month={Nov} }
 @article{rey-sánchez_slot_posada_kitajima_2016, title={Spatial and seasonal variation in leaf temperature within the canopy of a tropical forest}, volume={71}, ISSN={0936-577X 1616-1572}, url={http://dx.doi.org/10.3354/cr01427}, DOI={10.3354/cr01427}, abstractNote={Understanding leaf temperature (Tleaf) variation in the canopy of tropical forests is critical for accurately calculating net primary productivity because plant respiration and net photosynthesis are highly sensitive to temperature. The objectives of this study were to (1) quantify the spatiotemporal variation of Tleaf in a semi-deciduous tropical forest in Panama and (2) create a season-specific empirical model to predict Tleaf in the canopy. To achieve this, we used a 42 m tall construction crane for canopy access and monitored the microenvironment within the canopy of mature, 20−35 m tall trees of 5 tropical tree species during the wet and the dry season. Tleaf was correlated to photosynthetic photon flux density (PPFD) in the wet season but not in the dry season, possibly due to seasonal differences in wind speed, physiology, and canopy phenology. A structural equation model showed that Tleaf is best explained by air temperature (Tair) and PPFD in the wet season, whereas in the dry season, Tair alone predicted most of the variation in Tleaf. These results suggest the utility of an empirical approach to estimate Tleaf variability where simple meteoro logical data are available. This approach can be incorporated in future models of vegetation−atmosphere carbon and water exchange models of mature tropical forests with similar seasonality.}, number={1}, journal={Climate Research}, publisher={Inter-Research Science Center}, author={Rey-Sánchez, AC and Slot, M and Posada, JM and Kitajima, K}, year={2016}, month={Nov}, pages={75–89} }
 @article{slot_rey-sánchez_gerber_lichstein_winter_kitajima_2014, title={Thermal acclimation of leaf respiration of tropical trees and lianas: response to experimental canopy warming, and consequences for tropical forest carbon balance}, volume={20}, ISSN={1354-1013}, url={http://dx.doi.org/10.1111/gcb.12563}, DOI={10.1111/gcb.12563}, abstractNote={Abstract}, number={9}, journal={Global Change Biology}, publisher={Wiley}, author={Slot, Martijn and Rey-Sánchez, Camilo and Gerber, Stefan and Lichstein, Jeremy W. and Winter, Klaus and Kitajima, Kaoru}, year={2014}, month={May}, pages={2915–2926} }
 @article{slot_rey-sánchez_winter_kitajima_2014, title={Trait-based scaling of temperature-dependent foliar respiration in a species-rich tropical forest canopy}, volume={28}, ISSN={0269-8463}, url={http://dx.doi.org/10.1111/1365-2435.12263}, DOI={10.1111/1365-2435.12263}, abstractNote={Summary}, number={5}, journal={Functional Ecology}, publisher={Wiley}, author={Slot, Martijn and Rey-Sánchez, Camilo and Winter, Klaus and Kitajima, Kaoru}, editor={Poorter, LourensEditor}, year={2014}, month={Mar}, pages={1074–1086} }