Browsing by Subject "ENERGY-BALANCE CLOSURE"

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  • Mallick, Kaniska; Toivonen, Erika; Trebs, Ivonne; Boegh, Eva; Cleverly, James; Eamus, Derek; Koivusalo, Harri; Drewry, Darren; Arndt, Stefan K.; Griebel, Anne; Beringer, Jason; Garcia, Monica (2018)
    Thermal infrared sensing of evapotranspiration (E) through surface energy balance (SEB) models is challenging due to uncertainties in determining the aerodynamic conductance (g(A)) and due to inequalities between radiometric (T-R) and aerodynamic temperatures (T-0). We evaluated a novel analytical model, the Surface Temperature Initiated Closure (STIC1.2), that physically integrates T-R observations into a combined Penman-Monteith Shuttleworth-Wallace (PM-SW) framework for directly estimating E, and overcoming the uncertainties associated with T0 and gA determination. An evaluation of STIC1.2 against high temporal frequency SEB flux measurements across an aridity gradient in Australia revealed a systematic error of 10-52% in E from mesic to arid ecosystem, and low systematic error in sensible heat fluxes (H) (12-25%) in all ecosystems. Uncertainty in TR versus moisture availability relationship, stationarity assumption in surface emissivity, and SEB closure corrections in E were predominantly responsible for systematic E errors in arid and semi-arid ecosystems. A discrete correlation (r) of the model errors with observed soil moisture variance (r = 0.33-0.43), evaporative index (r = 0.77-0.90), and climatological dryness (r = 0.60-0.77) explained a strong association between ecohydrological extremes and T-R in determining the error structure of STIC1.2 predicted fluxes. Being independent of any leaf-scale biophysical parameterization, the model might be an important value addition in working group (WG2) of the Australian Energy and Water Exchange (OzEWEX) research initiative which focuses on observations to evaluate and compare biophysical models of energy and water cycle components. Plain Language Summary Evapotranspiration modeling and mapping in arid and semi-arid ecosystems are uncertain due to empirical approximation of surface and atmospheric conductances. Here we demonstrate the performance of a fully analytical model which is independent of any leaf-scale empirical parameterization of the conductances and can be potentially used for continental scale mapping of ecosystem water use as well as water stress using thermal remote sensing satellite data.d
  • Lind, Saara E.; Shurpali, Narasinha J.; Peltola, Olli; Mammarella, Ivan; Hyvonen, Niina; Maljanen, Marja; Raty, Mari; Virkajarvi, Perttu; Martikainen, Pertti J. (2016)
    One of the strategies to reduce carbon dioxide (CO2) emissions from the energy sector is to increase the use of renewable energy sources such as bioenergy crops. Bioenergy is not necessarily carbon neutral because of greenhouse gas (GHG) emissions during biomass production, field management and transportation. The present study focuses on the cultivation of reed canary grass (RCG, Phalaris arundinacea L.), a perennial bioenergy crop, on a mineral soil. To quantify the CO2 exchange of this RCG cultivation system, and to understand the key factors controlling its CO2 exchange, the net ecosystem CO2 exchange (NEE) was measured from July 2009 until the end of 2011 using the eddy covariance (EC) method. The RCG cultivation thrived well producing yields of 6200 and 6700 kg DW ha(-1) in 2010 and 2011, respectively. Gross photosynthesis (GPP) was controlled mainly by radiation from June to September. Vapour pressure deficit (VPD), air temperature or soil moisture did not limit photosynthesis during the growing season. Total ecosystem respiration (TER) increased with soil temperature, green area index and GPP. Annual NEE was -262 and -256 g C m(-2) in 2010 and 2011, respectively. Throughout the study period from July 2009 until the end of 2011, cumulative NEE was -575 g C m(-2). Carbon balance and its regulatory factors were compared to the published results of a comparison site on drained organic soil cultivated with RCG in the same climate. On this mineral soil site, the RCG had higher capacity to take up CO2 from the atmosphere than on the comparison site.
  • Carrara, Arnaud; Kolari, Pasi; de Beeck, Maarten Op; Arriga, Nicola; Berveiller, Daniel; Dengel, Sigrid; Ibrom, Andreas; Merbold, Lutz; Rebmann, Corinna; Sabbatini, Simone; Serrano-Ortiz, Penelope; Biraud, Sebastien C. (2018)
    Solar radiation is a key driver of energy and carbon fluxes in natural ecosystems. Radiation measurements are essential for interpreting ecosystem scale greenhouse gases and energy fluxes as well as many other observations performed at ecosystem stations of the Integrated Carbon Observation System (ICOS). We describe and explain the relevance of the radiation variables that arc monitored continuously at ICOS ecosystems stations and define recommendations to perform these measurements with consistent and comparable accuracy. The measurement methodology and instruments are described including detailed technical specifications. Guidelines for instrumental set up as well as for operation, maintenance and data collection arc defined considering both ICOS scientific objectives and practical operational constraints. For measurements of short-wave (solar) and long wave (infrared) radiation components, requirements for the ICOS network are based on available well-defined state-of-the art standards (World Meteorological Organization, International Organization for Standardization). For photosynthetically active radiation measurements, some basic instrumental requirements are based on the performance of commercially available sensors. Since site specific conditions and practical constraints at individual ICOS ecosystem stations may hamper the applicability of standard requirements, we recommend that ICOS develops mid-tern coordinated actions to assess the effective level of uncertainties in radiation measurements at the network scale.
  • Pastorello, Gilberto; Trotta, Carlo; Canfora, Eleonora; Chu, Housen; Christianson, Danielle; Cheah, You-Wei; Poindexter, Cristina; Chen, Jiquan; Elbashandy, Abdelrahman; Humphrey, Marty; Isaac, Peter; Polidori, Diego; Ribeca, Alessio; van Ingen, Catharine; Zhang, Leiming; Amiro, Brian; Ammann, Christof; Arain, M. Altaf; Ardo, Jonas; Arkebauer, Timothy; Arndt, Stefan K.; Arriga, Nicola; Aubinet, Marc; Aurela, Mika; Baldocchi, Dennis; Barr, Alan; Beamesderfer, Eric; Marchesini, Luca Belelli; Bergeron, Onil; Beringer, Jason; Bernhofer, Christian; Berveiller, Daniel; Billesbach, Dave; Black, Thomas Andrew; Blanken, Peter D.; Bohrer, Gil; Boike, Julia; Bolstad, Paul V.; Bonal, Damien; Bonnefond, Jean-Marc; Bowling, David R.; Bracho, Rosvel; Brodeur, Jason; Bruemmer, Christian; Buchmann, Nina; Burban, Benoit; Burns, Sean P.; Buysse, Pauline; Cale, Peter; Cavagna, Mauro; Cellier, Pierre; Chen, Shiping; Chini, Isaac; Christensen, Torben R.; Cleverly, James; Collalti, Alessio; Consalvo, Claudia; Cook, Bruce D.; Cook, David; Coursolle, Carole; Cremonese, Edoardo; Curtis, Peter S.; D'Andrea, Ettore; da Rocha, Humberto; Dai, Xiaoqin; Davis, Kenneth J.; De Cinti, Bruno; de Grandcourt, Agnes; De Ligne, Anne; De Oliveira, Raimundo C.; Delpierre, Nicolas; Desai, Ankur R.; Di Bella, Carlos Marcelo; di Tommasi, Paul; Dolman, Han; Domingo, Francisco; Dong, Gang; Dore, Sabina; Duce, Pierpaolo; Dufrene, Eric; Dunn, Allison; Dusek, Jiri; Eamus, Derek; Eichelmann, Uwe; ElKhidir, Hatim Abdalla M.; Eugster, Werner; Ewenz, Cacilia M.; Ewers, Brent; Famulari, Daniela; Fares, Silvano; Feigenwinter, Iris; Feitz, Andrew; Fensholt, Rasmus; Filippa, Gianluca; Fischer, Marc; Frank, John; Galvagno, Marta; Gharun, Mana; Gianelle, Damiano; Gielen, Bert; Gioli, Beniamino; Gitelson, Anatoly; Goded, Ignacio; Goeckede, Mathias; Goldstein, Allen H.; Gough, Christopher M.; Goulden, Michael L.; Graf, Alexander; Griebel, Anne; Gruening, Carsten; Gruenwald, Thomas; Hammerle, Albin; Han, Shijie; Han, Xingguo; Hansen, Birger Ulf; Hanson, Chad; Hatakka, Juha; He, Yongtao; Hehn, Markus; Heinesch, Bernard; Hinko-Najera, Nina; Hoertnagl, Lukas; Hutley, Lindsay; Ibrom, Andreas; Ikawa, Hiroki; Jackowicz-Korczynski, Marcin; Janous, Dalibor; Jans, Wilma; Jassal, Rachhpal; Jiang, Shicheng; Kato, Tomomichi; Khomik, Myroslava; Klatt, Janina; Knohl, Alexander; Knox, Sara; Kobayashi, Hideki; Koerber, Georgia; Kolle, Olaf; Kosugi, Yoshiko; Kotani, Ayumi; Kowalski, Andrew; Kruijt, Bart; Kurbatova, Julia; Kutsch, Werner L.; Kwon, Hyojung; Launiainen, Samuli; Laurila, Tuomas; Law, Bev; Leuning, Ray; Li, Yingnian; Liddell, Michael; Limousin, Jean-Marc; Lion, Marryanna; Liska, Adam J.; Lohila, Annalea; Lopez-Ballesteros, Ana; Lopez-Blanco, Efren; Loubet, Benjamin; Loustau, Denis; Lucas-Moffat, Antje; Lueers, Johannes; Ma, Siyan; Macfarlane, Craig; Magliulo, Vincenzo; Maier, Regine; Mammarella, Ivan; Manca, Giovanni; Marcolla, Barbara; Margolis, Hank A.; Marras, Serena; Massman, William; Mastepanov, Mikhail; Matamala, Roser; Matthes, Jaclyn Hatala; Mazzenga, Francesco; McCaughey, Harry; McHugh, Ian; McMillan, Andrew M. S.; Merbold, Lutz; Meyer, Wayne; Meyers, Tilden; Miller, Scott D.; Minerbi, Stefano; Moderow, Uta; Monson, Russell K.; Montagnani, Leonardo; Moore, Caitlin E.; Moors, Eddy; Moreaux, Virginie; Moureaux, Christine; Munger, J. William; Nakai, Taro; Neirynck, Johan; Nesic, Zoran; Nicolini, Giacomo; Noormets, Asko; Northwood, Matthew; Nosetto, Marcelo; Nouvellon, Yann; Novick, Kimberly; Oechel, Walter; Olesen, Jorgen Eivind; Ourcival, Jean-Marc; Papuga, Shirley A.; Parmentier, Frans-Jan; Paul-Limoges, Eugenie; Pavelka, Marian; Peichl, Matthias; Pendall, Elise; Phillips, Richard P.; Pilegaard, Kim; Pirk, Norbert; Posse, Gabriela; Powell, Thomas; Prasse, Heiko; Prober, Suzanne M.; Rambal, Serge; Rannik, Ullar; Raz-Yaseef, Naama; Reed, David; de Dios, Victor Resco; Restrepo-Coupe, Natalia; Reverter, Borja R.; Roland, Marilyn; Sabbatini, Simone; Sachs, Torsten; Saleska, Scott R.; Sanchez-Canete, Enrique P.; Sanchez-Mejia, Zulia M.; Schmid, Hans Peter; Schmidt, Marius; Schneider, Karl; Schrader, Frederik; Schroder, Ivan; Scott, Russell L.; Sedlak, Pavel; Serrano-Ortiz, Penelope; Shao, Changliang; Shi, Peili; Shironya, Ivan; Siebicke, Lukas; Sigut, Ladislav; Silberstein, Richard; Sirca, Costantino; Spano, Donatella; Steinbrecher, Rainer; Stevens, Robert M.; Sturtevant, Cove; Suyker, Andy; Tagesson, Torbern; Takanashi, Satoru; Tang, Yanhong; Tapper, Nigel; Thom, Jonathan; Tiedemann, Frank; Tomassucci, Michele; Tuovinen, Juha-Pekka; Urbanski, Shawn; Valentini, Riccardo; van der Molen, Michiel; van Gorsel, Eva; van Huissteden, Ko; Varlagin, Andrej; Verfaillie, Joseph; Vesala, Timo; Vincke, Caroline; Vitale, Domenico; Vygodskaya, Natalia; Walker, Jeffrey P.; Walter-Shea, Elizabeth; Wang, Huimin; Weber, Robin; Westermann, Sebastian; Wille, Christian; Wofsy, Steven; Wohlfahrt, Georg; Wolf, Sebastian; Woodgate, William; Li, Yuelin; Zampedri, Roberto; Zhang, Junhui; Zhou, Guoyi; Zona, Donatella; Agarwal, Deb; Biraud, Sebastien; Torn, Margaret; Papale, Dario (2020)
    The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as gap-filled time series, ecosystem respiration and photosynthetic uptake estimates, estimation of uncertainties, and metadata about the measurements, presented for the first time in this paper. In addition, 206 of these sites are for the first time distributed under a Creative Commons (CC-BY 4.0) license. This paper details this enhanced dataset and the processing methods, now made available as open-source codes, making the dataset more accessible, transparent, and reproducible.