Editorial Type:
Article
Article Type:
Research Article

Performance Evaluation of an Integrated Open-Path Eddy Covariance System in a Cold Desert Environment

Wei Wang Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China
Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Wei Wang in
Current site
Google Scholar
PubMed Close
,
Jiaping Xu Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Jiaping Xu in
Current site
Google Scholar
PubMed Close
,
Yunqiu Gao Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Yunqiu Gao in
Current site
Google Scholar
PubMed Close
,
Ivan Bogoev Research and Development, Campbell Scientific, Inc., Logan, Utah

Search for other papers by Ivan Bogoev in
Current site
Google Scholar
PubMed Close
,
Jian Cui Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Jian Cui in
Current site
Google Scholar
PubMed Close
,
Lichen Deng Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Lichen Deng in
Current site
Google Scholar
PubMed Close
,
Cheng Hu Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Cheng Hu in
Current site
Google Scholar
PubMed Close
,
Cheng Liu Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Cheng Liu in
Current site
Google Scholar
PubMed Close
,
Shoudong Liu Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Shoudong Liu in
Current site
Google Scholar
PubMed Close
,
Jing Shen Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Jing Shen in
Current site
Google Scholar
PubMed Close
,
Xiaomin Sun Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China

Search for other papers by Xiaomin Sun in
Current site
Google Scholar
PubMed Close
,
Wei Xiao Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Wei Xiao in
Current site
Google Scholar
PubMed Close
,
Guofu Yuan Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China

Search for other papers by Guofu Yuan in
Current site
Google Scholar
PubMed Close
, and
Xuhui Lee Yale–NUIST Center on Atmospheric Environment, Nanjing University of Information Science and Technology, Nanjing, China
School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut

Search for other papers by Xuhui Lee in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Nov 2016
DOI:
https://doi.org/10.1175/JTECH-D-15-0149.1
Page(s):
2385–2399
Restricted access

We are aware of a technical issue preventing figures and tables from showing in some newly published articles in the full-text HTML view.
While we are resolving the problem, please use the online PDF version of these articles to view figures and tables.

Abstract

Performance evaluation of an integrated eddy covariance (EC) instrument called the IRGASON, with a separated EC for reference, was conducted in a desert riparian Populus euphratica stand in the lower Tarim River basin in northwestern China. The separated EC consisted of an open-path gas analyzer and a sonic anemometer separated by 20 cm. The IRGASON integrates an open-path gas analyzer and a sonic anemometer into the same sensing volume, thus eliminating sensor separation in comparison to the traditional open-path EC setup. Integrating the infrared gas analyzer’s sensing head into the sensing volume of the sonic anemometer had negligible effects on wind speed and friction velocity observations of the IRGASON. Physiologically unreasonable daytime CO2 uptake was observed by both systems during the cold winter season (mean air temperature of −6.7°C), when the trees were dormant without any photosynthetic activities. The mean midday CO2 flux was −1.65 and −1.61 μmol m−2 s−1 for the IRGASON and the separated EC setup, respectively. No evidence was found for sensor self-heating as the cause of the apparent uptake CO2 flux. Instead, the uptake CO2 flux appeared to be an artifact of the spectroscopic effect of the IRGASON’s gas analyzer. After adjusting for this spectroscopic effect using a relationship with the sensible heat flux, the wintertime IRGASON CO2 flux became physiologically reasonable (mean value of −0.04 μmol m−2 s−1).

Supplemental information related to this paper is available at the Journals Online website: http://dx.doi.org/10.1175/JTECH-D-15-0149.s1.

Corresponding author address: Dr. Xuhui Lee, Sara Shallenberger Brown Professor of Meteorology, School of Forestry and Environmental Studies, Yale University, Kroon Hall, 195 Prospect Street, New Haven, CT 06511. E-mail: xuhui.lee@yale.edu

Abstract

Performance evaluation of an integrated eddy covariance (EC) instrument called the IRGASON, with a separated EC for reference, was conducted in a desert riparian Populus euphratica stand in the lower Tarim River basin in northwestern China. The separated EC consisted of an open-path gas analyzer and a sonic anemometer separated by 20 cm. The IRGASON integrates an open-path gas analyzer and a sonic anemometer into the same sensing volume, thus eliminating sensor separation in comparison to the traditional open-path EC setup. Integrating the infrared gas analyzer’s sensing head into the sensing volume of the sonic anemometer had negligible effects on wind speed and friction velocity observations of the IRGASON. Physiologically unreasonable daytime CO2 uptake was observed by both systems during the cold winter season (mean air temperature of −6.7°C), when the trees were dormant without any photosynthetic activities. The mean midday CO2 flux was −1.65 and −1.61 μmol m−2 s−1 for the IRGASON and the separated EC setup, respectively. No evidence was found for sensor self-heating as the cause of the apparent uptake CO2 flux. Instead, the uptake CO2 flux appeared to be an artifact of the spectroscopic effect of the IRGASON’s gas analyzer. After adjusting for this spectroscopic effect using a relationship with the sensible heat flux, the wintertime IRGASON CO2 flux became physiologically reasonable (mean value of −0.04 μmol m−2 s−1).

Supplemental information related to this paper is available at the Journals Online website: http://dx.doi.org/10.1175/JTECH-D-15-0149.s1.

Corresponding author address: Dr. Xuhui Lee, Sara Shallenberger Brown Professor of Meteorology, School of Forestry and Environmental Studies, Yale University, Kroon Hall, 195 Prospect Street, New Haven, CT 06511. E-mail: xuhui.lee@yale.edu
Save
Cover Journal of Atmospheric and Oceanic Technology
Journal of Atmospheric and Oceanic Technology

  • Amiro, B., 2010: Estimating annual carbon dioxide eddy fluxes using open-path analysers for cold forest sites. Agric. For. Meteor., 150, 1366–1372, doi:10.1016/j.agrformet.2010.06.007.

    • Search Google Scholar
    • Export Citation

  • Amiro, B., Orchansky A. , and Sass A. , 2006: A perspective on carbon dioxide flux measurements using an open-path infrared gas analyzer in cold environments. 27th Conf. on Agricultural and Forest Meteorology, San Diego, CA, Amer. Meteor. Soc., P4.7. [Available online at https://ams.confex.com/ams/BLTAgFBioA/techprogram/paper_110015.htm.]

  • Baldocchi, D., 2014: Measuring fluxes of trace gases and energy between ecosystems and the atmosphere—The state and future of the eddy covariance method. Global Change Biol., 20, 3600–3609, doi:10.1111/gcb.12649.

    • Search Google Scholar
    • Export Citation

  • Baldocchi, D., Finnigan J. , Wilson K. , Paw U K. T. , and Falge E. , 2000: On measuring net ecosystem carbon exchange over tall vegetation on complex terrain. Bound.-Layer Meteor., 96, 257–291, doi:10.1023/A:1002497616547.

    • Search Google Scholar
    • Export Citation

  • Blanken, P., Williams M. , Burns S. , Monson R. , Knowles J. , Chowanski K. , and Ackerman T. , 2009: A comparison of water and carbon dioxide exchange at a windy alpine tundra and subalpine forest site near Niwot Ridge, Colorado. Biogeochemistry, 95, 61–76, doi:10.1007/s10533-009-9325-9.

    • Search Google Scholar
    • Export Citation

  • Bogoev, I., 2014: Improved eddy flux measurements by open-path gas analyzer and sonic anemometer co-location. Geophysical Research Abstracts, Vol. 16, Abstract EGU2014-199. [Available online at http://meetingorganizer.copernicus.org/EGU2014/EGU2014-199.pdf.]

  • Bogoev, I., Helbig M. , and Sonnentag O. , 2015: On the importance of high-frequency air-temperature fluctuations for spectroscopic corrections of open-path carbon dioxide flux measurement. Geophysical Research Abstracts, Vol. 17, Abstract EGU2015-2333. [Available online at http://meetingorganizer.copernicus.org/EGU2015/EGU2015-2333.pdf.]

  • Bowling, D. R., Bethers-Marchetti S. , Lunch C. K. , Grote E. E. , and Belnap J. , 2010: Carbon, water, and energy fluxes in a semiarid cold desert grassland during and following multiyear drought. J. Geophys. Res., 115, G04026, doi:10.1029/2010JG001322.

    • Search Google Scholar
    • Export Citation

  • Burba, G. G., McDermitt D. K. , Grelle A. , Anderson D. J. , and Xu L. , 2008: Addressing the influence of instrument surface heat exchange on the measurements of CO2 flux from open-path gas analyzers. Global Change Biol., 14, 1854–1876, doi:10.1111/j.1365-2486.2008.01606.x.

    • Search Google Scholar
    • Export Citation

  • Cabral, O. M. R., Gash J. H. C. , Rocha H. R. , Marsden C. , Ligo M. A. V. , Freitas H. C. , Tatsch J. D. , and Gomes E. , 2011: Fluxes of CO2 above a plantation of Eucalyptus in southeast Brazil. Agric. For. Meteor., 151, 49–59, doi:10.1016/j.agrformet.2010.09.003.

    • Search Google Scholar
    • Export Citation

  • Campbell Scientific, Inc., 2016: IRGASON integrated CO2 and H2O open-path gas analyzer and 3-D sonic anemometer. Instruction Manual, 72 pp.

  • Chen, Y. N., Zilliacus H. , Li W. H. , Zhang H. F. , and Chen Y. P. , 2006: Ground-water level affects plant species diversity along the lower reaches of the Tarim River, western China. J. Arid Environ., 66, 231–246, doi:10.1016/j.jaridenv.2005.11.009.

    • Search Google Scholar
    • Export Citation

  • Detto, M., Verfaillie J. , Anderson F. , Xu L. , and Baldocchi D. , 2011: Comparing laser-based open- and closed-path gas analyzers to measure methane fluxes using the eddy covariance method. Agric. For. Meteor., 151, 1312–1324, doi:10.1016/j.agrformet.2011.05.014.

    • Search Google Scholar
    • Export Citation

  • Edson, J. B., and Coauthors, 2011: Direct covariance measurement of CO2 gas transfer velocity during the 2008 Southern Ocean Gas Exchange Experiment: Wind speed dependency. J. Geophys. Res., 116, C00F10, doi:10.1029/2011JC007022.

    • Search Google Scholar
    • Export Citation

  • El-Madany, T. S., Griessbaum F. , Fratini G. , Juang J. Y. , Chang S. C. , and Klemm O. , 2013: Comparison of sonic anemometer performance under foggy conditions. Agric. For. Meteor., 173, 63–73, doi:10.1016/j.agrformet.2013.01.005.

    • Search Google Scholar
    • Export Citation

  • Else, B. G. T., Papakyriakou T. N. , Galley R. J. , Drennan W. M. , Miller L. A. , and Thomas H. , 2011: Wintertime CO2 fluxes in an Arctic polynya using eddy covariance: Evidence for enhanced air-sea gas transfer during ice formation. J. Geophys. Res., 116, C00G03, doi:10.1029/2010JC006760.

    • Search Google Scholar
    • Export Citation

  • Garratt, J. R., 1992: The Atmospheric Boundary Layer. Cambridge Atmospheric and Space Science Series, Cambridge University Press, 316 pp.

  • Grelle, A., and Burba G. , 2007: Fine-wire thermometer to correct CO2 fluxes by open-path analyzers for artificial density fluctuations. Agric. For. Meteor., 147, 48–57, doi:10.1016/j.agrformet.2007.06.007.

    • Search Google Scholar
    • Export Citation

  • Ham, J. M., and Heilman J. L. , 2003: Experimental test of density and energy-balance corrections on carbon dioxide flux as measured using open-path eddy covariance. Agron. J., 95, 1393–1403, doi:10.2134/agronj2003.1393.

    • Search Google Scholar
    • Export Citation

  • Haslwanter, A., Hammerle A. , and Wohlfahrt G. , 2009: Open-path vs. closed-path eddy covariance measurements of the net ecosystem carbon dioxide and water vapour exchange: A long-term perspective. Agric. For. Meteor., 149, 291–302, doi:10.1016/j.agrformet.2008.08.011.

    • Search Google Scholar
    • Export Citation

  • Helbig, M., Humphreys E. , Bogoev I. , Quinton W. L. , Wischnweski K. , and Sonnentag O. , 2015: Effects of biased CO2 flux measurements by open-path sensors on the interpretation of CO2 flux dynamics at contrasting ecosystems. Geophysical Research Abstracts, Vol. 17, Abstract EGU2015-281-1. [Available online at http://meetingorganizer.copernicus.org/EGU2015/EGU2015-281-1.pdf.]

  • Hirata, R., Hirano T. , Saigusa N. , Fujinuma Y. , Inukai K. , Kitamori Y. , Takahashi Y. , and Yamamoto S. , 2007: Seasonal and interannual variations in carbon dioxide exchange of a temperate larch forest. Agric. For. Meteor., 147, 110–124, doi:10.1016/j.agrformet.2007.07.005.

    • Search Google Scholar
    • Export Citation

  • Horst, T. W., Semmer S. R. , and Maclean G. , 2015: Correction of a non-orthogonal, three-component sonic anemometer for flow distortion by transducer shadowing. Bound.-Layer Meteor., 155, 371–395, doi:10.1007/s10546-015-0010-3.

    • Search Google Scholar
    • Export Citation

  • Horst, T. W., Vogt R. , and Oncley S. P. , 2016: Measurements of flow distortion within the IRGASON integrated sonic anemometer and CO2/H2O gas analyzer. Bound.-Layer Meteor., 160, 1–15, doi:10.1007/s10546-015-0123-8.

    • Search Google Scholar
    • Export Citation

  • Ikawa, H., and Oechel W. C. , 2015: Temporal variations in air-sea CO2 exchange near large kelp beds near San Diego, California. J. Geophys. Res. Oceans, 120, 50–63, doi:10.1002/2014JC010229.

    • Search Google Scholar
    • Export Citation

  • Jamieson, J. A., McFee R. , Plass G. , Grube R. , and Richards R. , 1963: Infrared Physics and Engineering. Inter-University Electronics Series, Vol. 1, McGraw-Hill, 673 pp.

  • Järvi, L., and Coauthors, 2009: Comparison of net CO2 fluxes measured with open-and closed-path infrared gas analyzers in an urban complex environment. Boreal Environ. Res., 14, 499–514.

    • Search Google Scholar
    • Export Citation

  • Järvi, L., Nordbo A. , Junninen H. , Riikonen A. , Moilanen J. , Nikinmaa E. , and Vesala T. , 2012: Seasonal and annual variation of carbon dioxide surface fluxes in Helsinki, Finland, in 2006–2010. Atmos. Chem. Phys., 12, 8475–8489, doi:10.5194/acp-12-8475-2012.

    • Search Google Scholar
    • Export Citation

  • Kaimal, J. C., and Finnigan J. J. , 1994: Atmospheric Boundary Layer Flows: Their Structure and Measurement. Oxford University Press, 289 pp.

  • Kondo, F., Ono K. , Mano M. , Miyata A. , and Tsukamoto O. , 2014: Experimental evaluation of water vapour cross-sensitivity for accurate eddy covariance measurement of CO2 flux using open-path CO2/H2O gas analysers. Tellus, 66B, 23803, doi:10.3402/tellusb.v66.23803.

    • Search Google Scholar
    • Export Citation

  • Lafleur, P. M., and Humphreys E. R. , 2008: Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada. Global Change Biol., 14, 740–756, doi:10.1111/j.1365-2486.2007.01529.x.

    • Search Google Scholar
    • Export Citation

  • Lee, X., and Massman W. , 2011: A perspective on thirty years of the Webb, Pearman and Leuning density corrections. Bound.-Layer Meteor., 139, 37–59, doi:10.1007/s10546-010-9575-z.

    • Search Google Scholar
    • Export Citation

  • Lee, X., Finnigan K. T. , and Paw U K. T. , 2005: Coordinate systems and flux bias error. Handbook of Micrometeorology: A Guide for Surface Flux Measurement and Analysis, X. Lee, W. Massman, and B. Law, Eds., Atmospheric and Oceanographic Sciences Library, Vol. 29, Kluwer Academic Publishers, 33–66.

  • LI-COR, Inc., 2010: LI-7700 open path CH4 gas analyzer instruction manual. 11/2010 980-11617, LI-COR Biosciences, 12 pp. [Available online at https://www.licor.com/env/pdf/gas_analyzers/7700/7700_brochure.pdf.]

  • Loescher, H. W., and Coauthors, 2005: Comparison of temperature and wind statistics in contrasting environments among different sonic anemometer–thermometers. Agric. For. Meteor., 133, 119–139, doi:10.1016/j.agrformet.2005.08.009.

    • Search Google Scholar
    • Export Citation

  • Lund, M., and Coauthors, 2015: Low impact of dry conditions on the CO2 exchange of a Northern-Norwegian blanket bog. Environ. Res. Lett., 10, 025004, doi:10.1088/1748-9326/10/2/025004.

    • Search Google Scholar
    • Export Citation

  • Ma, J., Wang Z.-Y. , Stevenson B. A. , Zheng X.-J. , and Li Y. , 2013: An inorganic CO2 diffusion and dissolution process explains negative CO2 fluxes in saline/alkaline soils. Sci. Rep., 3, 2025, doi:10.1038/srep02025.

    • Search Google Scholar
    • Export Citation

  • Marcolla, B., and Coauthors, 2011: Climatic controls and ecosystem responses drive the inter-annual variability of the net ecosystem exchange of an alpine meadow. Agric. For. Meteor., 151, 1233–1243, doi:10.1016/j.agrformet.2011.04.015.

    • Search Google Scholar
    • Export Citation

  • Marushchak, M. E., and Coauthors, 2013: Carbon dioxide balance of subarctic tundra from plot to regional scales. Biogeosciences, 10, 437–452, doi:10.5194/bg-10-437-2013.

    • Search Google Scholar
    • Export Citation

  • McDermitt, D., and Coauthors, 2011: A new low-power, open-path instrument for measuring methane flux by eddy covariance. Appl. Phys., 102B, 391–405, doi:10.1007/s00340-010-4307-0.

    • Search Google Scholar
    • Export Citation

  • Miller, L. A., and Coauthors, 2011: Carbon dynamics in sea ice: A winter flux time series. J. Geophys. Res., 116, C02028, doi:10.1029/2011JC007143.

    • Search Google Scholar
    • Export Citation

  • Moore, C. J., 1986: Frequency response corrections for eddy correlation systems. Bound.-Layer Meteor., 37, 17–35, doi:10.1007/BF00122754.

    • Search Google Scholar
    • Export Citation

  • Nakai, T., Iwata H. , Harazono Y. , and Ueyama M. , 2014: An inter-comparison between Gill and Campbell sonic anemometers. Agric. For. Meteor., 195–196, 123–131, doi:10.1016/j.agrformet.2014.05.005.

    • Search Google Scholar
    • Export Citation

  • Ono, K., Miyata A. , and Yamada T. , 2008: Apparent downward CO2 flux observed with open-path eddy covariance over a non-vegetated surface. Theor. Appl. Climatol., 92, 195–208, doi:10.1007/s00704-007-0323-3.

    • Search Google Scholar
    • Export Citation

  • Peel, M. C., Finlayson B. L. , and McMahon T. A. , 2007: Updated world map of the Köppen-Geiger climate classification. Hydrol. Earth Syst. Sci., 11, 1633–1644, doi:10.5194/hess-11-1633-2007.

    • Search Google Scholar
    • Export Citation

  • Reverter, B. R., Sánchez-Cañete E. P. , Resco V. , Serrano-Ortiz P. , Oyonarte C. , and Kowalski A. S. , 2010: Analyzing the major drivers of NEE in a Mediterranean alpine shrubland. Biogeosciences, 7, 2601–2611, doi:10.5194/bg-7-2601-2010.

    • Search Google Scholar
    • Export Citation

  • Reverter, B. R., and Coauthors, 2011: Adjustment of annual NEE and ET for the open-path IRGA self-heating correction: Magnitude and approximation over a range of climate. Agric. For. Meteor., 151, 1856–1861, doi:10.1016/j.agrformet.2011.06.001.

    • Search Google Scholar
    • Export Citation

  • Richiardone, R., Manfrin M. , Ferrarese S. , Francone C. , Fernicola V. , Gavioso R. M. , and Mortarini L. , 2012: Influence of the sonic anemometer temperature calibration on turbulent heat-flux measurements. Bound.-Layer Meteor., 142, 425–442, doi:10.1007/s10546-011-9688-z.

    • Search Google Scholar
    • Export Citation

  • Stone, R., 2008: Have Desert Researchers Discovered a Hidden Loop in the Carbon Cycle? Science, 320, 1409–1410, doi:10.1126/science.320.5882.1409.

    • Search Google Scholar
    • Export Citation

  • Wauben, W. M. F., and van Krimpen R. , 2008: Operational test of sonic wind sensors at KNMI. [Available online at http://www.wmo.int/pages/prog/www/IMOP/publications/IOM-96_TECO-2008/P2%2828%29_Wauben_Netherlands.pdf.]

  • Webb, E. K., Pearman G. I. , and Leuning R. , 1980: Correction of flux measurements for density effects due to heat and water vapour transfer. Quart. J. Roy. Meteor. Soc., 106, 85–100, doi:10.1002/qj.49710644707.

    • Search Google Scholar
    • Export Citation

  • Welles, J. M., and McDermitt D. K. , 2005: Measuring carbon dioxide in the atmosphere. Micrometeorology in Agricultural Systems, J. L. Hatfield, J. M. Baker, and M. K. Viney, Eds., Agronomy Series, Vol. 47, American Society of Agronomy, Inc., Crop Science Society of America, Inc., and Soil Science Society of America, Inc. Publishers, 287–320.

  • Welp, L. R., Randerson J. T. , and Liu H. P. , 2007: The sensitivity of carbon fluxes to spring warming and summer drought depends on plant functional type in boreal forest ecosystems. Agric. For. Meteor., 147, 172–185, doi:10.1016/j.agrformet.2007.07.010.

    • Search Google Scholar
    • Export Citation

  • Wohlfahrt, G., Fenstermaker L. F. , and Arnone J. A. III, 2008: Large annual net ecosystem CO2 uptake of a Mojave Desert ecosystem. Global Change Biol., 14, 1475–1487, doi:10.1111/j.1365-2486.2008.01593.x.

    • Search Google Scholar
    • Export Citation

  • Yang, Z.-H., and E Y.-H. , 2000: A phenology research on the main xylophyte in arid desert area—A example on cultivated plants of Minqin desert botanical garden (in Chinese). Acta Bot. Boreali-Occident. Sin., 6, 1102–1109.

    • Search Google Scholar
    • Export Citation

  • Yuan, G. F., Luo Y. , Shao M. A. , Zhang P. , and Zhu X. C. , 2015: Evapotranspiration and its main controlling mechanism over the desert riparian forests in the lower Tarim River Basin. Sci. China Earth Sci., 58, 1032–1042, doi:10.1007/s11430-014-5045-7.

    • Search Google Scholar
    • Export Citation

  • Zhang, J., Lee X. , Song G. , and Han S. , 2011: Pressure correction to the long-term measurement of carbon dioxide flux. Agric. For. Meteor., 151, 70–77, doi:10.1016/j.agrformet.2010.09.004.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 4954 896 199
PDF Downloads 770 191 27