Long-term record of atmospheric CO<sub xmlns="">2</sub> and stable isotopic ratios at Waliguan Observatory: Seasonally averaged 1991–2002 source/sink signals, and a comparison of 1998–2002 record to the 11 selected sites in the Northern Hemisphere

@article{citeulike:620765, abstract = {This paper investigates seasonally averaged atmospheric CO₂ source or sink signals observed at Waliguan Baseline Observatory (WLG, 36\&deg;17\&\#8242;N, 100\&deg;54\&\#8242;E, 3816 m asl) in western China from 1991 to 2002. Both linear and geometric mean regressions as well as statistical significance test were performed between detrended CO₂ and stable isotope monthly data by means of Keeling Model and Miller-Tans Model. The estimated slope \&\#916;\&\#948;¹³C/\&\#916;CO₂ due to the seasonality in CO₂ and \&\#948;¹³C is (\&\#8722;0.050 \&plusmn; 0.004)\&\#8240; ppm^\&\#8722;1, the mean source/sink isotopic signatures \&\#948;_s (i.e., \&\#948;¹³C_s and \&\#948;¹⁸O_s) are (\&\#8722;26.159 \&plusmn; 1.924)\&\#8240; and (\&\#8722;7.662 \&plusmn; 2.113)\&\#8240;, respectively, and the mean atmospheric \&\#948;¹³C discrimination \&\#948;_dis (i.e., \&\#948;_s minus \&\#948;_bg) where the \&\#948;_bg is the isotopic value of the background atmosphere was (\&\#8722;18.174 \&plusmn; 1.959)\&\#8240; by the Keeling Model, in agreement with results from other continental background sites in the Northern Hemisphere. We suggest that exchange with terrestrial biosphere dominates the observed CO₂, \&\#948;¹³C and \&\#948;¹⁸O seasonal cycles at WLG. In addition, atmospheric CO₂ and \&\#948;¹³C data from 11 selected NH sites in the NOAA ESRL air sampling network from 1998 to 2002 were analyzed and compared to the WLG data for the same period to better address common and specific features observed in this region. The annual cycle amplitude differences, secular and seasonal \&\#916;\&\#948;¹³C/\&\#916;CO₂ discrepancies among sites will be useful to better understand carbon uptake and release especially on the Eurasian continent. The estimated \&\#948;_s during certain times at each specific site could possibly provide useful information on CO₂ fluxes.}, author = {Zhou, Lingxi and White, James W. C. and Conway, Thomas J. and Mukai, Hitoshi and Macclune, Kenneth and Zhang, Xiaochun and Wen, Yupu and Li, Jinlong }, citeulike-article-id = {620765}, doi = {http://dx.doi.org/10.1029/2004GB002431}, journal = {Global Biogeochemical Cycles}, keywords = {carbondioxide, cv\_km, isotopes}, month = {April}, pages = {GB2001+}, posted-at = {2006-05-09 23:24:04}, priority = {0}, title = {Long-term record of atmospheric CO<sub xmlns="">2</sub> and stable isotopic ratios at Waliguan Observatory: Seasonally averaged 1991\&\#8211;2002 source/sink signals, and a comparison of 1998\&\#8211;2002 record to the 11 selected sites in the Northern Hemisphere}, url = {http://dx.doi.org/10.1029/2004GB002431}, volume = {20}, year = {2006} }

TY - JOUR ID - citeulike:620765 L3 - citeulike-article-id:620765 TI - Long-term record of atmospheric CO<sub xmlns="">2</sub> and stable isotopic ratios at Waliguan Observatory: Seasonally averaged 1991&#8211;2002 source/sink signals, and a comparison of 1998&#8211;2002 record to the 11 selected sites in the Northern Hemisphere JF - Global Biogeochemical Cycles VL - 20 SP - GB2001 N2 - This paper investigates seasonally averaged atmospheric CO₂ source or sink signals observed at Waliguan Baseline Observatory (WLG, 36&deg;17&#8242;N, 100&deg;54&#8242;E, 3816 m asl) in western China from 1991 to 2002. Both linear and geometric mean regressions as well as statistical significance test were performed between detrended CO₂ and stable isotope monthly data by means of Keeling Model and Miller-Tans Model. The estimated slope &#916;&#948;¹³C/&#916;CO₂ due to the seasonality in CO₂ and &#948;¹³C is (&#8722;0.050 &plusmn; 0.004)&#8240; ppm^&#8722;1, the mean source/sink isotopic signatures &#948;_s (i.e., &#948;¹³C_s and &#948;¹⁸O_s) are (&#8722;26.159 &plusmn; 1.924)&#8240; and (&#8722;7.662 &plusmn; 2.113)&#8240;, respectively, and the mean atmospheric &#948;¹³C discrimination &#948;_dis (i.e., &#948;_s minus &#948;_bg) where the &#948;_bg is the isotopic value of the background atmosphere was (&#8722;18.174 &plusmn; 1.959)&#8240; by the Keeling Model, in agreement with results from other continental background sites in the Northern Hemisphere. We suggest that exchange with terrestrial biosphere dominates the observed CO₂, &#948;¹³C and &#948;¹⁸O seasonal cycles at WLG. In addition, atmospheric CO₂ and &#948;¹³C data from 11 selected NH sites in the NOAA ESRL air sampling network from 1998 to 2002 were analyzed and compared to the WLG data for the same period to better address common and specific features observed in this region. The annual cycle amplitude differences, secular and seasonal &#916;&#948;¹³C/&#916;CO₂ discrepancies among sites will be useful to better understand carbon uptake and release especially on the Eurasian continent. The estimated &#948;_s during certain times at each specific site could possibly provide useful information on CO₂ fluxes. KW - carbondioxide KW - cv_km KW - isotopes AU - Zhou, Lingxi AU - White, James AU - Conway, Thomas AU - Mukai, Hitoshi AU - Macclune, Kenneth AU - Zhang, Xiaochun AU - Wen, Yupu AU - Li, Jinlong PY - 2006/04/05/ UR - http://dx.doi.org/10.1029/2004GB002431 ER -