المؤلفون: Cooke, Colin A., Emmerton, Craig A., Drevnick, Paul E.

المصدر: In Environmental Pollution 1 March 2024 344

المؤلفون: Virkkala, Anna-Maria, Natali, Susan M, Rogers, Brendan M, Watts, Jennifer D, Savage, Kathleen, Connon, Sara June, Mauritz, Marguerite, Schuur, Edward AG, Peter, Darcy, Minions, Christina, Nojeim, Julia, Commane, Roisin, Emmerton, Craig A, Goeckede, Mathias, Helbig, Manuel, Holl, David, Iwata, Hiroki, Kobayashi, Hideki, Kolari, Pasi, López-Blanco, Efrén, Marushchak, Maija E, Mastepanov, Mikhail, Merbold, Lutz, Parmentier, Frans-Jan W, Peichl, Matthias, Sachs, Torsten, Sonnentag, Oliver, Ueyama, Masahito, Voigt, Carolina, Aurela, Mika, Boike, Julia, Celis, Gerardo, Chae, Namyi, Christensen, Torben R, Bret-Harte, M Syndonia, Dengel, Sigrid, Dolman, Han, Edgar, Colin W, Elberling, Bo, Euskirchen, Eugenie, Grelle, Achim, Hatakka, Juha, Humphreys, Elyn, Järveoja, Järvi, Kotani, Ayumi, Kutzbach, Lars, Laurila, Tuomas, Lohila, Annalea, Mammarella, Ivan, Matsuura, Yojiro, Meyer, Gesa, Nilsson, Mats B, Oberbauer, Steven F, Park, Sang-Jong, Petrov, Roman, Prokushkin, Anatoly S, Schulze, Christopher, St. Louis, Vincent L, Tuittila, Eeva-Stiina, Tuovinen, Juha-Pekka, Quinton, William, Varlagin, Andrej, Zona, Donatella, Zyryanov, Viacheslav I

المصدر: Earth System Science Data. 14(1)

مصطلحات موضوعية: Earth Sciences, Physical Geography and Environmental Geoscience, Atmospheric Sciences, Geoinformatics, Geochemistry, Atmospheric sciences, Physical geography and environmental geoscience

الوصف: Past efforts to synthesize and quantify the magnitude and change in carbon dioxide (CO2) fluxes in terrestrial ecosystems across the rapidly warming Arctic-boreal zone (ABZ) have provided valuable information but were limited in their geographical and temporal coverage. Furthermore, these efforts have been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting their potential to be used in large-scale carbon budget assessments. To bridge these gaps, we developed a standardized monthly database of Arctic-boreal CO2 fluxes (ABCflux) that aggregates in situ measurements of terrestrial net ecosystem CO2 exchange and its derived partitioned component fluxes: gross primary productivity and ecosystem respiration. The data span from 1989 to 2020 with over 70 supporting variables that describe key site conditions (e.g., vegetation and disturbance type), micrometeorological and environmental measurements (e.g., air and soil temperatures), and flux measurement techniques. Here, we describe these variables, the spatial and temporal distribution of observations, the main strengths and limitations of the database, and the potential research opportunities it enables. In total, ABCflux includes 244 sites and 6309 monthly observations; 136 sites and 2217 monthly observations represent tundra, and 108 sites and 4092 observations represent the boreal biome. The database includes fluxes estimated with chamber (19% of the monthly observations), snow diffusion (3%) and eddy covariance (78%) techniques. The largest number of observations were collected during the climatological summer (June-August; 32%), and fewer observations were available for autumn (September-October; 25%), winter (December-February; 18%), and spring (March-May; 25%). ABCflux can be used in a wide array of empirical, remote sensing and modeling studies to improve understanding of the regional and temporal variability in CO2 fluxes and to better estimate the terrestrial ABZ CO2 budget. ABCflux is openly and freely available online (Virkkala et al., 2021b, 10.3334/ORNLDAAC/1934). Copyright:

وصف الملف: application/pdf

URL الوصول: https://escholarship.org/uc/item/66w7n3cw

المؤلفون: Emmerton, Craig A.^{Aff1, Aff2, IDs1002102200745w_cor1}, Drevnick, Paul E., Serbu, Jessica A., Cooke, Colin A.^{Aff1, Aff4}, Graydon, Jennifer A., Reichert, Megan, Evans, Marlene S., McMaster, Mark E.

المصدر: Ecosystems. 26(1):114-133

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المؤلفون: Virkkala, Anna Maria, Aalto, Juha, Rogers, Brendan M., Tagesson, Torbern, Treat, Claire C., Natali, Susan M., Watts, Jennifer D., Potter, Stefano, Lehtonen, Aleksi, Mauritz, Marguerite, Schuur, Edward A.G., Kochendorfer, John, Zona, Donatella, Oechel, Walter, Kobayashi, Hideki, Humphreys, Elyn, Goeckede, Mathias, Iwata, Hiroki, Lafleur, Peter M., Euskirchen, Eugenie S., Bokhorst, Stef, Marushchak, Maija, Martikainen, Pertti J., Elberling, Bo, Voigt, Carolina, Biasi, Christina, Sonnentag, Oliver, Parmentier, Frans Jan W., Ueyama, Masahito, Celis, Gerardo, St.Louis, Vincent L., Emmerton, Craig A., Peichl, Matthias, Chi, Jinshu, Järveoja, Järvi, Nilsson, Mats B., Oberbauer, Steven F., Torn, Margaret S., Park, Sang Jong, Dolman, Han, Mammarella, Ivan, Chae, Namyi, Poyatos, Rafael, López-Blanco, Efrén, Christensen, Torben Røjle, Kwon, Min Jung, Sachs, Torsten, Holl, David, Luoto, Miska

المصدر: Global Change Biology BECC: Biodiversity and Ecosystem services in a Changing Climate MERGE: ModElling the Regional and Global Earth system. 27(17):4040-4059

مصطلحات موضوعية: Arctic, CO balance, empirical, greenhouse gas, land, permafrost, remote sensing, Naturvetenskap, Geovetenskap och miljövetenskap, Natural Sciences, Earth and Related Environmental Sciences

الوصف: The regional variability in tundra and boreal carbon dioxide (CO2) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990–2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to analyze the spatial patterns and drivers of CO2 fluxes and test the accuracy and uncertainty of different statistical models. CO2 fluxes were upscaled at relatively high spatial resolution (1 km2) across the high-latitude region using five commonly used statistical models and their ensemble, that is, the median of all five models, using climatic, vegetation, and soil predictors. We found the performance of machine learning and ensemble predictions to outperform traditional regression methods. We also found the predictive performance of NEE-focused models to be low, relative to models predicting GPP and ER. Our data compilation and ensemble predictions showed that CO2 sink strength was larger in the boreal biome (observed and predicted average annual NEE −46 and −29 g C m−2 yr−1, respectively) compared to tundra (average annual NEE +10 and −2 g C m−2 yr−1). This pattern was associated with large spatial variability, reflecting local heterogeneity in soil organic carbon stocks, climate, and vegetation productivity. The terrestrial ecosystem CO2 budget, estimated using the annual NEE ensemble prediction, suggests the high-latitude region was on average an annual CO2 sink during 1990–2015, although uncertainty remains high.

URL الوصول: https://lup.lub.lu.se/record/5eb7eac8-80c0-4c81-8b3d-6621ae9ad588
http://dx.doi.org/10.1111/gcb.15659

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المؤلفون: Emmerton, Craig A., Cooke, Colin A., Hustins, Sarah, Silins, Uldis, Emelko, Monica B., Lewis, Ted, Kruk, Mary K., Taube, Nadine, Zhu, Dongnan, Jackson, Brian, Stone, Michael, Kerr, Jason G., Orwin, John F.

المصدر: In Water Research 15 September 2020 183

المؤلفون: Wang, Ran, Gamon, John A., Emmerton, Craig A., Springer, Kyle R., Yu, Rong, Hmimina, Gabriel

المصدر: In Agricultural and Forest Meteorology 15 February 2020 281

المؤلفون: Oh, Youmi, Stackhouse, Brandon, Lau, Maggie CY, Xu, Xiangtao, Trugman, Anna T, Moch, Jonathan, Onstott, Tullis C, Jørgensen, Christian J, D'Imperio, Ludovica, Elberling, Bo, Emmerton, Craig A, St. Louis, Vincent L, Medvigy, David

المصدر: Geophysical Research Letters. 43(10)

مصطلحات موضوعية: Meteorology & Atmospheric Sciences

وصف الملف: application/pdf

URL الوصول: https://escholarship.org/uc/item/5593j8mw

المؤلفون: Wang, Ran, Gamon, John A, Emmerton, Craig A, Li, Haitao, Nestola, Enrica, Pastorello, Gilberto Z, Menzer, Olaf

المصدر: Remote Sensing. 8(3)

مصطلحات موضوعية: Physical Geography and Environmental Geoscience, Earth Sciences, Engineering, Geomatic Engineering, Atmospheric Sciences, Life Below Water, biomass, eddy covariance, remote sensing, grassland, biodiversity, Classical Physics, Atmospheric sciences, Physical geography and environmental geoscience, Geomatic engineering

الوصف: Grasslands play important roles in ecosystem production and support a large farming and grazing industry. An accurate and efficient way is needed to estimate grassland health and production for monitoring and adjusting management to get sustainable products and other ecosystem services. Previous studies of grasslands have shown varying relationships between productivity and biodiversity, with most showing either a positive or a hump-shaped relationship where productivity peaks at intermediate diversity. In this study, we used airborne imaging spectrometry combined with ground sampling and eddy covariance measurements to estimate the spatial pattern of production and biodiversity for two sites of contrasting productivity in a southern Alberta prairie ecosystem. Resulting patterns revealed that more diverse sites generally had greater productivity, supporting the hypothesis of a positive relationship between production and biodiversity for this site. We showed that the addition of evenness to richness (using the Shannon Index of dominant species instead of the number of dominant species alone) improved the correlation with optical diversity, an optically derived metric of biodiversity based on the coefficient of variation in spectral reflectance across space. Similarly, the Shannon Index was better correlated with productivity (estimated via NDVI (Normalized Difference Vegetation Index)) than the number of dominant species alone. Optical diversity provided a potent proxy for other more traditional biodiversity metrics (richness and Shannon index). Coupling field measurements and imaging spectrometry provides a method for assessing grassland productivity and biodiversity at a larger scale than can be sampled from the ground, and allows the integrated analysis of the productivity-biodiversity relationship over large areas.

URL الوصول: https://escholarship.org/uc/item/2cd2r8bq