1
|
Liang M, Zhang Y, Ma Q, Yu D, Chen X, Cohen JB. Dramatic decline of observed atmospheric CO 2 and CH 4 during the COVID-19 lockdown over the Yangtze River Delta of China. J Environ Sci (China) 2023; 124:712-722. [PMID: 36182176 PMCID: PMC9515762 DOI: 10.1016/j.jes.2021.09.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/01/2021] [Accepted: 09/26/2021] [Indexed: 06/16/2023]
Abstract
The temporal variation of greenhouse gas concentrations in China during the COVID-19 lockdown in China is analyzed in this work using high resolution measurements of near surface △CO2, △CH4 and △CO concentrations above the background conditions at Lin'an station (LAN), a regional background station in the Yangtze River Delta region. During the pre-lockdown observational period (IOP-1), both △CO2 and △CH4 exhibited a significant increasing trend relative to the 2011-2019 climatological mean. The reduction of △CO2, △CH4 and △CO during the lockdown observational period (IOP-2) (which also coincided with the Chinese New Year Holiday) reached up to 15.0 ppm, 14.2 ppb and 146.8 ppb, respectively, and a reduction of △CO2/△CO probably due to a dramatic reduction from industrial emissions. △CO2, △CH4 and △CO were observed to keep declining during the post-lockdown easing phase (IOP-3), which is the synthetic result of lower than normal CO2 emissions from rural regions around LAN coupled with strong uptake of the terrestrial ecosystem. Interestingly, the trend reversed to gradual increase for all species during the later easing phase (IOP-4), with △CO2/△CO constantly increasing from IOP-2 to IOP-3 and finally IOP-4, consistent with recovery in industrial emissions associated with the staged resumption of economic activity. On average, △CO2 declined sharply throughout the days during IOP-2 but increased gradually throughout the days during IOP-4. The findings showcase the significant role of emission reduction in accounting for the dramatic changes in measured atmospheric △CO2 and △CH4 associated with the COVID-19 lockdown and recovery.
Collapse
Affiliation(s)
- Miao Liang
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China
| | - Yong Zhang
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China.
| | - Qianli Ma
- Lin'an Atmospheric Regional Background Station, China Meteorological Administration (CMA), Hangzhou 311307, China
| | - Dajiang Yu
- Longfengshan Regional Background Station, China Meteorological Administration (CMA), Heilongjiang 150200, China
| | - Xiaojian Chen
- Shanxi Meteorological Information Center, China Meteorological Administration (CMA), Shanxi 030000, China
| | - Jason Blake Cohen
- School of Environment and Spatial Informatics, China University of Mining and Technology, Xuzhou, 221116, China
| |
Collapse
|
2
|
Diurnal and Seasonal Variations of Carbon Dioxide (CO2) Concentration in Urban, Suburban, and Rural Areas around Tokyo. ATMOSPHERE 2018. [DOI: 10.3390/atmos9100367] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Site environments and instrumental characteristics of carbon dioxide (CO2) measurements operated by local governments in the Kanto Plain, the center of which is Tokyo, were summarized for this study. The observation sites were classified into environments of three types: urban, suburban, and woodland. Based on a few decades of accumulated hourly data, the diurnal and seasonal variations of CO2 concentrations were analyzed as a composite of anomalies from annual means recorded for each site. In urban areas, the highest concentrations appear before midnight in winter. The second peak corresponds to the morning rush hour and the strengthening of the inversion layer. Suburban areas can be characterized as having the highest concentration before dawn and the lowest concentration during the daytime in summer in association with the activation of respiration and photosynthesis of vegetation. In these areas, concentration peaks also appear during the morning rush hour. Woodland areas show background features, with the highest concentration in early spring, which are higher than the global background by about 5 ppmv.
Collapse
|
3
|
Wei S, Yi C, Fang W, Hendrey G. A global study of GPP focusing on light-use efficiency in a random forest regression model. Ecosphere 2017. [DOI: 10.1002/ecs2.1724] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Suhua Wei
- School of Earth and Environmental Sciences; Queens College; City University of New York; 65-30 Kissena Boulevard Flushing New York 11367 USA
- The Graduate Center; City University of New York; New York New York 10016 USA
| | - Chuixiang Yi
- School of Earth and Environmental Sciences; Queens College; City University of New York; 65-30 Kissena Boulevard Flushing New York 11367 USA
- The Graduate Center; City University of New York; New York New York 10016 USA
| | - Wei Fang
- School of Earth and Environmental Sciences; Queens College; City University of New York; 65-30 Kissena Boulevard Flushing New York 11367 USA
| | - George Hendrey
- School of Earth and Environmental Sciences; Queens College; City University of New York; 65-30 Kissena Boulevard Flushing New York 11367 USA
- The Graduate Center; City University of New York; New York New York 10016 USA
| |
Collapse
|
4
|
Liu S, Zhuang Q, Chen M, Gu L. Quantifying spatially and temporally explicit
CO
2
fertilization effects on global terrestrial ecosystem carbon dynamics. Ecosphere 2016. [DOI: 10.1002/ecs2.1391] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Shaoqing Liu
- Department of Earth, Atmospheric, and Planetary Sciences Purdue University West Lafayette Indiana 47907 USA
| | - Qianlai Zhuang
- Department of Earth, Atmospheric, and Planetary Sciences Purdue University West Lafayette Indiana 47907 USA
- Department of Agronomy Purdue University West Lafayette Indiana 47907 USA
| | - Min Chen
- Department of Global Ecology Carnegie Institution for Science Stanford California 94305 USA
| | - Lianhong Gu
- Environmental Sciences Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA
| |
Collapse
|
5
|
Pérez IA, Sánchez ML, García MÁ, Pardo N. An experimental relationship between airflow and carbon dioxide concentrations at a rural site. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 533:432-438. [PMID: 26179780 DOI: 10.1016/j.scitotenv.2015.06.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 05/29/2015] [Accepted: 06/28/2015] [Indexed: 06/04/2023]
Abstract
The influence of airflow on CO2 concentrations is considered. Two years of measurements recorded with a Picarro G1301 analyser during the night at a rural site were used. Three concentration groups were formed and were related to wind speed. Yearly, directional, and hourly evolution indicated that the isolated contribution of factors affecting CO2 concentrations proves hard to evaluate. Two approaches to airflow based on average wind and a rotating residual were considered. Around two thirds of observations corresponded to anticyclonic rotations. Firstly, circular hodographs of rotating residuals indicated that wavelengths were in the mesoscale range. The greatest concentrations were linked to the lowest wind speeds and no prevailing directions were revealed by the roundness calculation in a spatial analysis using hexagonal cells. Secondly, composite hodographs for anticyclonic turnings were calculated, the greatest concentrations being associated to hodographs with a pronounced curvature. Moreover, these were successfully parameterised using two models. A harmonic function was first used, which satisfactorily fitted hodographs linked to low and intermediate concentrations. The second model initially described the wind direction of residuals with the error function since its change was slow in early and late night-time. Residuals were later parameterised with a second order logarithmic spiral. This procedure successfully fitted the most curved hodographs of low and high concentrations.
Collapse
Affiliation(s)
- Isidro A Pérez
- Department of Applied Physics, Faculty of Sciences, University of Valladolid, Paseo de Belén, 7, 47011 Valladolid, Spain.
| | - M Luisa Sánchez
- Department of Applied Physics, Faculty of Sciences, University of Valladolid, Paseo de Belén, 7, 47011 Valladolid, Spain
| | - M Ángeles García
- Department of Applied Physics, Faculty of Sciences, University of Valladolid, Paseo de Belén, 7, 47011 Valladolid, Spain
| | - Nuria Pardo
- Department of Applied Physics, Faculty of Sciences, University of Valladolid, Paseo de Belén, 7, 47011 Valladolid, Spain
| |
Collapse
|
6
|
Desai AR. Influence and predictive capacity of climate anomalies on daily to decadal extremes in canopy photosynthesis. PHOTOSYNTHESIS RESEARCH 2014; 119:31-47. [PMID: 24078353 DOI: 10.1007/s11120-013-9925-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 09/12/2013] [Indexed: 06/02/2023]
Abstract
Significant advances have been made over the past decades in capabilities to simulate diurnal and seasonal variation of leaf-level and canopy-scale photosynthesis in temperate and boreal forests. However, long-term prediction of future forest productivity in a changing climate may be more dependent on how climate and biological anomalies influence extremes in interannual to decadal variability of canopy ecosystem carbon exchanges. These exchanges can differ markedly from leaf level responses, especially owing to the prevalence of long lags in nutrient and water cycling. Until recently, multiple long-term (10+ year) high temporal frequency (daily) observations of canopy exchange were not available to reliably assess this claim. An analysis of one of the longest running North American eddy covariance flux towers reveals that single climate variables do not adequately explain carbon exchange anomalies beyond the seasonal timescale. Daily to weekly lagged anomalies of photosynthesis positively autocorrelate with daily photosynthesis. This effect suggests a negative feedback in photosynthetic response to climate extremes, such as anomalies in evapotranspiration and maximum temperature. Moisture stress in the prior season did inhibit photosynthesis, but mechanisms are difficult to assess. A complex interplay of integrated and lagged productivity and moisture-limiting factors indicate a critical role of seasonal thresholds that limit growing season length and peak productivity. These results lead toward a new conceptual framework for improving earth system models with long-term flux tower observations.
Collapse
|
7
|
Marr LC, Moore TO, Klapmeyer ME, Killar MB. Comparison of NO(x) fluxes measured by eddy covariance to emission inventories and land use. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1800-1808. [PMID: 23316911 DOI: 10.1021/es303150y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Uncertainty in emission inventories remains a critical limitation of air quality modeling and management. Using eddy covariance, we measured surface-atmosphere exchange fluxes of nitrogen oxides (NO(x)) at the neighborhood scale at 13 sites in the Norfolk, Virginia area to estimate emissions, to evaluate official inventories, and to quantify relationships between emissions and land use. Average daytime fluxes ranged from 0.4 μg m(-2) s(-1) at a site near open water to 9.5 μg m(-2) s(-1) at a site dominated by vehicle traffic. NO(x) fluxes were correlated with both road density and medium- plus high-intensity development, confirming that both motor vehicles and sources associated with development are responsible for NO(x) emissions in urban areas. Spatially averaged NO(x) fluxes measured by eddy covariance agreed to within 3% with the National Emission Inventory (NEI) but were 2.8 times higher than those in the corresponding grid cell of an emission inventory developed for air quality modeling. These average fluxes were 4.6, 4.5, and 1.7 μg m(-2) s(-1), respectively. Uncertainty in the inventories appears to be dominated by the nonroad mobile source category. It is especially important to know NO(x) emissions accurately because in certain photochemical regimes, reducing NO(x) emissions can exacerbate secondary pollutant formation.
Collapse
Affiliation(s)
- Linsey C Marr
- Via Department of Civil and Environmental Engineering, Virginia Tech, 411 Durham Hall, Blacksburg, Virginia 24061, USA.
| | | | | | | |
Collapse
|
8
|
Dang X, Lai CT, Hollinger DY, Schauer AJ, Xiao J, Munger JW, Owensby C, Ehleringer JR. Combining tower mixing ratio and community model data to estimate regional-scale net ecosystem carbon exchange by boundary layer inversion over four flux towers in the United States. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jg001554] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
9
|
Wang G, Huang J, Guo W, Zuo J, Wang J, Bi J, Huang Z, Shi J. Observation analysis of land-atmosphere interactions over the Loess Plateau of northwest China. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jd013372] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
10
|
Aubinet M. Eddy covariance CO2 flux measurements in nocturnal conditions: an analysis of the problem. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2008; 18:1368-1378. [PMID: 18767616 DOI: 10.1890/06-1336.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A detailed analysis of the various processes at work in stable boundary layers was made. It pointed out that two main mechanisms may affect eddy covariance measurements in stable conditions and that their impacts were different. On one hand, intermittent turbulence produces strongly nonstationary events during which the validity of turbulent transport and storage measurements is uncertain. On the other hand, during breeze and drainage flow events, significant advection takes place and competes with turbulent flux and storage. Intermittent turbulence questions both the ability of eddy covariance systems to adequately capture turbulent flux and storage and the representativeness of the measurements. Ability of the systems to capture the fluxes could be improved by adapting the averaging time period or the high pass filtering characteristics. However, beyond this, the question of representativeness of the flux remains open as the flux measured during an intermittent turbulence event represents not only the source term, but also the removal of CO2 that built up in the control volume and that cannot be simply related to the source term. In these conditions, the u* discrimination is likely to be insufficient and should be completed with a stationarity criterion. Further research should allow determining better selection criteria. Advection occurs mainly in presence of flows associated with topographical slopes (drainage flows) or with land use changes (breezes). Direct advection measurements were performed at several sites, but the results were shown to be strongly site dependent. A classification based on the general flow pattern and on the source intensity evolution along streamlines was proposed here. Five different patterns were identified that helped to classify the different observations. The classification was found to be a fairly good fit for the observations. This could serve as a tool to better understand and quantify the fluxes at sites subjected to repeatable patterns.
Collapse
Affiliation(s)
- Marc Aubinet
- Faculté Universitaire des Sciences Agronomiques de Gembloux, Unité de Physique des Biosystèmes, 8 Avenue de la Faculté, B-5030 Gembloux, Belgium.
| |
Collapse
|
11
|
Yi C, Anderson DE, Turnipseed AA, Burns SP, Sparks JP, Stannard DI, Monson RK. The contribution of advective fluxes to net ecosystem exchange in a high-elevation, subalpine forest. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2008; 18:1379-1390. [PMID: 18767617 DOI: 10.1890/06-0908.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The eddy covariance technique, which is used in the determination of net ecosystem CO2 exchange (NEE), is subject to significant errors when advection that carries CO2 in the mean flow is ignored. We measured horizontal and vertical advective CO2 fluxes at the Niwot Ridge AmeriFlux site (Colorado, USA) using a measurement approach consisting of multiple towers. We observed relatively high rates of both horizontal (F(hadv)) and vertical (F(vadv)) advective fluxes at low surface friction velocities (u(*)) which were associated with downslope katabatic flows. We observed that F(hadv) was confined to a relatively thin layer (0-6 m thick) of subcanopy air that flowed beneath the eddy covariance sensors principally at night, carrying with it respired CO2 from the soil and lower parts of the canopy. The observed F(vadv) came from above the canopy and was presumably due to the convergence of drainage flows at the tower site. The magnitudes of both F(hadv) and F(vadv) were similar, of opposite sign, and increased with decreasing u(*), meaning that they most affected estimates of the total CO2 flux on calm nights with low wind speeds. The mathematical sign, temporal variation and dependence on u(*) of both F(hadv) and F(vadv) were determined by the unique terrain of the Niwot Ridge site. Therefore, the patterns we observed may not be broadly applicable to other sites. We evaluated the influence of advection on the cumulative annual and monthly estimates of the total CO2 flux (F(c)), which is often used as an estimate of NEE, over six years using the dependence of F(hadv) and F(vadv) on u(*). When the sum of F(hadv) and F(vadv) was used to correct monthly F(c), we observed values that were different from the monthly F(c) calculated using the traditional u(*)-filter correction by--16 to 20 g C x m(-2) x mo(-1); the mean percentage difference in monthly Fc for these two methods over the six-year period was 10%. When the sum of F(hadv) and F(vadv) was used to correct annual Fc, we observed a 65% difference compared to the traditional u(*)-filter approach. Thus, the errors to the local CO2 budget, when F(hadv) and F(vadv) are ignored, can become large when compounded in cumulative fashion over long time intervals. We conclude that the "micrometeorological" (using observations of F(hadv) and F(vadv)) and "biological" (using the u(*) filter and temperature vs. F(c) relationship) corrections differ on the basis of fundamental mechanistic grounds. The micrometeorological correction is based on aerodynamic mechanisms and shows no correlation to drivers of biological activity. Conversely, the biological correction is based on climatic responses of organisms and has no physical connection to aerodynamic processes. In those cases where they impose corrections of similar magnitude on the cumulative F(c) sum, the result is due to a serendipitous similarity in scale but has no clear mechanistic explanation.
Collapse
Affiliation(s)
- Chuixiang Yi
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309-0334, USA
| | | | | | | | | | | | | |
Collapse
|
12
|
Tóta J, Fitzjarrald DR, Staebler RM, Sakai RK, Moraes OMM, Acevedo OC, Wofsy SC, Manzi AO. Amazon rain forest subcanopy flow and the carbon budget: Santarém LBA-ECO site. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jg000597] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Julio Tóta
- Instituto Nacional de Pesquisas da Amazônia, Manaus; Amazonas Brazil
| | - David R. Fitzjarrald
- Atmospheric Sciences Research Center; University at Albany, State University of New York; Albany New York USA
| | - Ralf M. Staebler
- Air Quality Research Branch, Environment Canada; Toronto, Ontario Canada
| | - Ricardo K. Sakai
- Atmospheric Sciences Research Center; University at Albany, State University of New York; Albany New York USA
| | - Osvaldo M. M. Moraes
- Departamento de Física; Universidade Federal de Santa Maria, Santa Maria; Rio Grande do Sul Brazil
| | - Otávio C. Acevedo
- Departamento de Física; Universidade Federal de Santa Maria, Santa Maria; Rio Grande do Sul Brazil
| | - Steven C. Wofsy
- Department of Earth and Planetary Sciences; Harvard University; Cambridge Massachusetts USA
| | - Antonio O. Manzi
- Instituto Nacional de Pesquisas da Amazônia, Manaus; Amazonas Brazil
| |
Collapse
|
13
|
Casso-Torralba P, Vilà-Guerau de Arellano J, Bosveld F, Soler MR, Vermeulen A, Werner C, Moors E. Diurnal and vertical variability of the sensible heat and carbon dioxide budgets in the atmospheric surface layer. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009583] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
14
|
Karipot A, Leclerc MY, Zhang G, Lewin KF, Nagy J, Hendrey GR, Starr G. Influence of nocturnal low-level jet on turbulence structure and CO2flux measurements over a forest canopy. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009149] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
15
|
Effects of Coniferous Plantation Thinning on Annual Interception Evaporation:. ACTA ACUST UNITED AC 2008. [DOI: 10.4005/jjfs.91.94] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
16
|
Gibert F, Schmidt M, Cuesta J, Ciais P, Ramonet M, Xueref I, Larmanou E, Flamant PH. Retrieval of average CO2fluxes by combining in situ CO2measurements and backscatter lidar information. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd008190] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Fabien Gibert
- Institut Pierre Simon Laplace, Laboratoire de Météorologie Dynamique; Ecole Polytechnique; Palaiseau, Cedex France
| | - Martina Schmidt
- Institut Pierre Simon Laplace, Laboratoire des Sciences du Climat et de l’Environnement; UMR CEA/CNRS 1572, ; Gif-sur-Yvette, Cedex France
| | - Juan Cuesta
- Institut Pierre Simon Laplace, Laboratoire de Météorologie Dynamique; Ecole Polytechnique; Palaiseau, Cedex France
| | - Philippe Ciais
- Institut Pierre Simon Laplace, Laboratoire des Sciences du Climat et de l’Environnement; UMR CEA/CNRS 1572, ; Gif-sur-Yvette, Cedex France
| | - Michel Ramonet
- Institut Pierre Simon Laplace, Laboratoire des Sciences du Climat et de l’Environnement; UMR CEA/CNRS 1572, ; Gif-sur-Yvette, Cedex France
| | - Irène Xueref
- Institut Pierre Simon Laplace, Laboratoire des Sciences du Climat et de l’Environnement; UMR CEA/CNRS 1572, ; Gif-sur-Yvette, Cedex France
| | - Eric Larmanou
- INRA Unité Mixte de Recherche INRA/INAPG “Environnement et Grandes Cultures”; Thiverval-Grignon France
| | - Pierre Henri Flamant
- Institut Pierre Simon Laplace, Laboratoire de Météorologie Dynamique; Ecole Polytechnique; Palaiseau, Cedex France
| |
Collapse
|
17
|
Wang JW, Denning AS, Lu L, Baker IT, Corbin KD, Davis KJ. Observations and simulations of synoptic, regional, and local variations in atmospheric CO2. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007410] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
18
|
Chen JM, Chen B, Tans P. Deriving daily carbon fluxes from hourly CO2mixing ratios measured on the WLEF tall tower: An upscaling methodology. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jg000280] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
19
|
Loescher HW, Law BE, Mahrt L, Hollinger DY, Campbell J, Wofsy SC. Uncertainties in, and interpretation of, carbon flux estimates using the eddy covariance technique. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006932] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
20
|
Chen B. Interannual variability in the atmospheric CO2rectification over a boreal forest region. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jd005546] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
21
|
Yi C, Monson RK, Zhai Z, Anderson DE, Lamb B, Allwine G, Turnipseed AA, Burns SP. Modeling and measuring the nocturnal drainage flow in a high-elevation, subalpine forest with complex terrain. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005jd006282] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
22
|
Chen B, Chen JM, Liu J, Chan D, Higuchi K, Shashkov A. A Vertical Diffusion Scheme to estimate the atmospheric rectifier effect. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003jd003925] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Baozhang Chen
- Department of Geography and Program in Planning; University of Toronto; Toronto Ontario Canada
| | - Jing M. Chen
- Department of Geography and Program in Planning; University of Toronto; Toronto Ontario Canada
| | - Jane Liu
- Department of Physics; University of Toronto; Toronto Ontario Canada
| | - Douglas Chan
- Air Quality Research Branch; Meteorological Service of Canada; Toronto Ontario Canada
| | - Kaz Higuchi
- Air Quality Research Branch; Meteorological Service of Canada; Toronto Ontario Canada
| | - Alexander Shashkov
- Air Quality Research Branch; Meteorological Service of Canada; Toronto Ontario Canada
| |
Collapse
|
23
|
Yi C. Observed covariance between ecosystem carbon exchange and atmospheric boundary layer dynamics at a site in northern Wisconsin. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003jd004164] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|