Larry L. Tieszen
Bruce K. Wylie
Lawrence B. Flanagan
Albert B. Frank
Marshall R. Haferkamp
Tilden P. Meyers
Jack A. Morgan
Tagir G. Gilmanov
2005
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<p><strong>Aim </strong> Extrapolation of tower CO<sub>2</sub> fluxes will be greatly facilitated if robust relationships between flux components and remotely sensed factors are established. Long-term measurements at five Northern Great Plains locations were used to obtain relationships between CO<sub>2</sub>fluxes and photosynthetically active radiation (<i>Q</i>), other on-site factors, and Normalized Difference Vegetation Index (<i>NDVI</i>) from the SPOT VEGETATION data set.</p>
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<div class="para">
<p><strong>Location </strong> CO<sub>2</sub> flux data from the following stations and years were analysed: Lethbridge, Alberta 1998–2001; Fort Peck, MT 2000, 2002; Miles City, MT 2000–01; Mandan, ND 1999–2001; and Cheyenne, WY 1997–98.</p>
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<p><strong>Results </strong> Analyses based on light-response functions allowed partitioning net CO<sub>2</sub> flux (<i>F</i>) into gross primary productivity (<i>P</i><sub><i>g</i></sub>) and ecosystem respiration (<i>R</i><sub><i>e</i></sub>). Weekly averages of daytime respiration, γ<sub><i>day</i></sub>, estimated from light responses were closely correlated with weekly averages of measured night-time respiration, γ<sub><i>night</i></sub> (<i>R</i><sup>2</sup> 0.64 to 0.95). Daytime respiration tended to be higher than night-time respiration, and regressions of γ<sub><i>day</i></sub> on γ<sub><i>night</i></sub> for all sites were different from 1 : 1 relationships. Over 13 site-years, gross primary production varied from 459 to 2491 g CO<sub>2</sub> m<sup>−2</sup> year<sup>−1</sup>, ecosystem respiration from 996 to 1881 g CO<sub>2</sub> m<sup>−2</sup> year<sup>−1</sup>, and net ecosystem exchange from −537 (source) to +610 g CO<sub>2</sub> m<sup>−2</sup> year<sup>−1</sup> (sink). Maximum daily ecological light-use efficiencies, ɛ<sub><i>d</i>,<i>max</i></sub> = <i>P</i><sub><i>g</i></sub><i>/Q</i>, were in the range 0.014 to 0.032 mol CO<sub>2</sub> (mol incident quanta)<sup>−1</sup>.</p>
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<div class="para">
<p><strong>Main conclusions </strong> Ten-day average <i>P</i><sub><i>g</i></sub> was significantly more highly correlated with <i>NDVI</i> than 10-day average daytime flux, <i>P</i><sub><i>d</i></sub> (<i>R</i><sup>2</sup> = 0.46 to 0.77 for <i>P</i><sub><i>g</i></sub><i>-NDVI</i> and 0.05 to 0.58 for <i>P</i><sub><i>d</i></sub><i>-NDVI</i> relationships). Ten-day average <i>R</i><sub><i>e</i></sub> was also positively correlated with <i>NDVI</i>, with <i>R</i><sup>2</sup>values from 0.57 to 0.77. Patterns of the relationships of <i>P</i><sub><i>g</i></sub> and <i>R</i><sub><i>e</i></sub> with <i>NDVI</i> and other factors indicate possibilities for establishing multivariate functions allowing scaling-up local fluxes to larger areas using GIS data, temporal NDVI, and other factors.</p>
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application/pdf
10.1111/j.1466-822X.2005.00151.x
en
Wiley
Integration of CO2 flux and remotely-sensed data for primary production and ecosystem respiration analyses in the Northern Great Plains: potential for quantitative spatial extrapolation
article