1. Introduction
1
Jing M. Chen 1 , Feng Deng 1 , Misa Ishizawa 1 , Chiu-Wai Yuen 1 , Gang Mo 1 , Kaz Higuchi 2 , and Douglas Chen 1 Department of Geography, University of Toronto, 100 St. George Street, Toronto, Ontario, Canada M5S 3G3 2 Air Quality Research Division, Environment Canada, Toronto, Ontario, Canada M3H 5T4 A NESTED GLOBAL INVERSION SYSTEM WITH A FOCUS ON NORTH AMERICA: COMPARISON WITH 1994-2003 BOTTOM-UP RESULTS IN CANADA 1. Introduction Based on the existing TransCom inversion for 22 global regions, we developed a nested global inversion system for estimating carbon fluxes for 30 regions in North America (2 of the 22 regions are divided into 30). Irregular boundaries of these 30 regions are delineated based partially on ecosystem types and partially on provincial/state borders, so that the major ecosystems in North America are separated (Deng et al., 2007). Synthesis Bayesian inversions are conducted on monthly time steps from 1994 to 2003 using CO 2 concentration measurements at 83 coastal and continental stations located over the globe (GlobalView database). Responses of these stations to carbon fluxes from the 50 regions are simulated using the transport model from the National Institute of Environmental Studies (NIES) of Japan driven by the National Center for Environmental Prediction (NCEP) meteorology. Terrestrial carbon flux fields used as a priori to constrain the inversion are obtained from CASA, while the Boreal Ecosystem Productivity Simulator (BEPS) is used with NIES to produce the response function. Bottom-up modeling for Canada’s forests and wetlands over the 1901-2003 period has been carried out using the Integrated Terrestrial Ecosystem Carbon Cycle Model (InTEC), which integrates disturbance and non-disturbance (climate, nitrogen, CO 2 ) effects on the carbon cycle. Bottom-up results indicate that sinks in Canada’s forests and wetlands varied from -0.045 to 0.165 Pg C/y. 2. Nested Global Inverse Modeling (Top-down) 2.1 Regions: The global surface is divided into 30 regions in North America and 20 regions for the rest of the globe (Fig. 1). The 20 regions are the same as those used in TransCom 3. 2.2 Models • NIES (National Institute of Environmental Studies of Japan), a transport model, driven by NCEP wind fields • BEPS, an ecosystem model, driven by global LAI in 2003 retrieved using VEGETATION 10-day synthesis imagery and 6-hourly NCEP meteorological data from 1992 to 2004. Fig. 1. Distribution of 30 regions in North America and 20 regions for the rest of the globe. 83 baseline and continental CO2 measurements stations are used in the inversion. 3. Remote Sensing-Based Ecosystem Modeling for Canada (Bottom-up) Bottom-up modeling for Canada’s forests and wetlands over the 1901-2000 period was previously conducted in annual time steps at 1 km resolution using the Integrated Terrestrial Ecosystem Carbon Cycle Model (InTEC). The input spatial data include land cover, leaf area index, fire scar, soil texture, 100 year climate, nitrogen deposition, and forest stand age. A Canada-wide forest stand age map in 1998 was derived by combining a recent forest inventory, a large fire polygon database, and fire scars dated using remote sensing images. This bottom-up modeling is recently improved through: (i) reducing the modeling time steps from annual to monthly, and (ii) incorporating a simple hydrological model to consider the mutual baseflow among pixels and its effects on soil moisture, net primary productivity and heterotrophic respiration. This hydrological model is validated using over 80 non-regulated river discharge station data. 4. Results and Analysis 4.1 Top-down results Two versions of GlobalView data are used in the inversion. The 2004 version produces the daily mean CO 2 concentration at the continental sites for all historical measurements, while the 2005 version uses the mid-afternoon average of CO 2 concentration. Due to the planetary boundary layer dynamics, the 2005 version gives smaller CO 2 concentrations than that in the 2004 version, and the difference can influence inversion considerably. The carbon source and sink distribution among the 30 regions, inverted using the 2004 version of GlobalView data, are shown in Fig. 4, and the corresponding distribution for the global 50 regions is shown in Fig. 5. The inversion results show that the terrestrial carbon sink in North America varied in the range from 0.534 to 1.112 ± 0.20 Pg C/y during the 1992-2003 period, with Canada showing sinks in the range from 0.004 to 0.313 ± 0.15 Pg C/y. 4.2 Top-down and bottom-up comparison The coarse spatial distribution pattern of terrestrial carbon sinks and sources derived from top-down modeling (Fig. 4) resembles, to certain extent, the fine spatial distribution through bottom-up modeling (Fig. 3). However, the top-down results show considerably larger sinks than the bottom-up results (Fig. 6). Replacing the 2004 version of GlobalView data with the 2005 version further increases the top-down sinks (Fig. 6). Theoretically, the 2005 version would match better with the setup of the transport model NIES, which uses the monthly average day-time mixed layer height to represent the transport within the mixed layer. However, we found that the low Fig. 3. Net biome productivity (NBP) for Canada’s forests and wetlands averaged for the 1994-2003 period, simulated using InTEC at 1 km resolution in monthly time steps from 1901 to 2003. Note the correspondence of NBP with forest age shown in Fig. 2. Old forests are close to carbon neutral, young forests are carbon sources, and mid age (30-80 years old) forests are generally carbon sinks. Wetlands are carbon sinks. Climate change induced longer growing seasons and better nutrient conditions and hence larger sinks. These climate changes effects are so far stronger in the south than in the north. b Fig 2. Forest age map derived using forest inventory around 1990 (processed to 10 km resolution), large fire polygons from 1959 to 1996 (gridded to 1 km resolution), and fire scar and age detected using VEGETATION images in 1998 at 1 km resolution. This forest age map allows for the first order estimation of disturbance and regrowth. References: Brenkert, A.L. 1998. Carbon dioxide emission estimates from fossil-fuel burning, hydraulic cement production, and gas flaring for 1995 on a one degree grid cell basis,http://cdiac.esd.ornl.gov/ndps/ndp058a.html, Carbon Dioxide Inf. Anal. Cent., Oak Ridge, Natl. Lab., Oak Ridge, Tenn. Deng, F., J. M. Chen, C.-W. Yuen, M. Ishizawa, G. Mo, K. Higuchi, D. Chan, B. Chen, and S. Maksyutov. 2007. Global monthly CO 2 flux inversion with focus over North America. Tellus (in press). GLOBALVIEW-CO2: Cooperative Atmospheric Data Integration Project – Carbon Dioxide. CD-ROM, NOAA CMDL, Boulder, Colorado [Also available on Internet via anonymous FTP to ftp.cmdl.noaa.gov, Path: ccg/co2/GLOBALVIEW], 2005. Marland, G., T.A. Boden, and R. J. Andres. 2006. Global, Regional, and National CO 2 Emissions. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A . Takahashi, T., R. Wanninkhof, R. A. Feely, et al. 1999. Net sea-air CO 2 flux over the global oceans: An improved estimate based on the sea-air pCO 2 difference, in Proceedings of the 2nd International Symposium on CO2 in the Oceans, the 12th global oceans: An improved estimate based on the sea-air pCO2 difference, in Proceedings of Fig. 4. The annual net CO 2 flux (NBP) of the 30 regions in North America, averaged for the 1994-2003 period. Fig. 6. Year-by-year comparison of bottom-up and top-down NBP results. The 2005 version of the GlobalView data result in larger sinks than the 2004 version. Acknowledgement: This research was supported by the Canadian Foundation for Climate and Atmospheric Sciences. From April 2007, it will become part of the Canadian Carbon Program. The availability of GlobalView dataset on the FTP site is greatly appreciated. D ecadalC Flux change ofC anada's forests and w etlands -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Flux (Pg C /yr) Top-dow n,G V04 Top-dow n,G V05 B ottom -up Poster presented at the Joint North America Carbon Program meeting, Colorado Spring, January 25-26 2.3 Key Datasets • Globalview baseline station CO 2 data + tall towers (2004 and 2005 versions, separately). 83 stations (Fig. 1) • Ocean carbon balance (Takahashi et al., 1999) • Global field of fossil fuel emission in 1995 (Brenkert, 1998), + national emission inventories in from 1995 to 2003 (Marland et al., 2006) • CASA NEP results averaged for 1994- 2003 as the a priori for all years for bottom-up constraint Fig. 5. The annual net CO2 flux (NBP) of the 50 regions of the globe, averaged for the 1994-2003 period, inverted using the 2004 version of the GlobalView data. summer CO 2 values over the continental sites in the 2005 version can induce even larger sinks if their errors are assumed to be the same as those in the 2004 version. In order to use the continental sites in the inversion in a compatible manner, a transport model that can resolve the diurnal mixed layer dynamics would be needed. Environment Environnement Canada Canada
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A NESTED GLOBAL INVERSION SYSTEM WITH A FOCUS ON NORTH AMERICA: COMPARISON WITH 1994-2003 BOTTOM-UP RESULTS IN CANADA. Jing M. Chen 1 , Feng Deng 1 , Misa Ishizawa 1 , Chiu-Wai Yuen 1 , Gang Mo 1 , Kaz Higuchi 2 , and Douglas Chen 2 - PowerPoint PPT Presentation
Transcript of 1. Introduction
Jing M. Chen1, Feng Deng1, Misa Ishizawa1, Chiu-Wai Yuen1, Gang Mo1, Kaz Higuchi2, and Douglas Chen2
1Department of Geography, University of Toronto, 100 St. George Street, Toronto, Ontario, Canada M5S 3G32Air Quality Research Division, Environment Canada, Toronto, Ontario, Canada M3H 5T4
A NESTED GLOBAL INVERSION SYSTEM WITH A FOCUS ON NORTH AMERICA:
COMPARISON WITH 1994-2003 BOTTOM-UP RESULTS IN CANADA
1. IntroductionBased on the existing TransCom inversion for 22 global regions, we developed a nested global inversion system for estimating carbon fluxes for 30 regions in North America (2 of the 22 regions are divided into 30). Irregular boundaries of these 30 regions are delineated based partially on ecosystem types and partially on provincial/state borders, so that the major ecosystems in North America are separated (Deng et al., 2007). Synthesis Bayesian inversions are conducted on monthly time steps from 1994 to 2003 using CO2 concentration measurements at 83 coastal and continental stations located over the globe (GlobalView database). Responses of these stations to carbon fluxes from the 50 regions are simulated using the transport model from the National Institute of Environmental Studies (NIES) of Japan driven by the National Center for Environmental Prediction (NCEP) meteorology. Terrestrial carbon flux fields used as a priori to constrain the inversion are obtained from CASA, while the Boreal Ecosystem Productivity Simulator (BEPS) is used with NIES to produce the response function. Bottom-up modeling for Canada’s forests and wetlands over the 1901-2003 period has been carried out using the Integrated Terrestrial Ecosystem Carbon Cycle Model (InTEC), which integrates disturbance and non-disturbance (climate, nitrogen, CO2) effects on the carbon cycle. Bottom-up results indicate that sinks in Canada’s forests and wetlands varied from -0.045 to 0.165 Pg C/y.
2. Nested Global Inverse Modeling (Top-down)2.1 Regions: The global surface is divided into 30 regions in North America and 20 regions for the rest of the globe (Fig. 1). The 20 regions are the same as those used in TransCom 3. 2.2 Models
• NIES (National Institute of Environmental Studies of Japan), a transport model, driven by NCEP wind fields• BEPS, an ecosystem model, driven by global LAI in 2003 retrieved using VEGETATION 10-day synthesis imagery and 6-hourly NCEP meteorological data from 1992 to 2004.
Fig. 1. Distribution of 30 regions in North America and 20 regions for the rest of the globe. 83 baseline and continental CO2 measurements stations are used in the inversion.
3. Remote Sensing-Based Ecosystem Modeling for Canada (Bottom-up)Bottom-up modeling for Canada’s forests and wetlands over the 1901-2000 period was previously conducted in annual time steps at 1 km resolution using the Integrated Terrestrial Ecosystem Carbon Cycle Model (InTEC). The input spatial data include land cover, leaf area index, fire scar, soil texture, 100 year climate, nitrogen deposition, and forest stand age. A Canada-wide forest stand age map in 1998 was derived by combining a recent forest inventory, a large fire polygon database, and fire scars dated using remote sensing images. This bottom-up modeling is recently improved through: (i) reducing the modeling time steps from annual to monthly, and (ii) incorporating a simple hydrological model to consider the mutual baseflow among pixels and its effects on soil moisture, net primary productivity and heterotrophic respiration. This hydrological model is validated using over 80 non-regulated river discharge station data.
4. Results and Analysis
4.1 Top-down results
Two versions of GlobalView data are used in the inversion. The 2004 version produces the daily mean CO2 concentration at the continental sites for all historical measurements, while the 2005 version uses the mid-afternoon average of CO2 concentration. Due to the planetary boundary layer dynamics, the 2005 version gives smaller CO2 concentrations than that in the 2004 version, and the difference can influence inversion considerably.
The carbon source and sink distribution among the 30 regions, inverted using the 2004 version of GlobalView data, are shown in Fig. 4, and the corresponding distribution for the global 50 regions is shown in Fig. 5. The inversion results show that the terrestrial carbon sink in North America varied in the range from 0.534 to 1.112 ± 0.20 Pg C/y during the 1992-2003 period, with Canada showing sinks in the range from 0.004 to 0.313 ± 0.15 Pg C/y.
4.2 Top-down and bottom-up comparison
The coarse spatial distribution pattern of terrestrial carbon sinks and sources derived from top-down modeling (Fig. 4) resembles, to certain extent, the fine spatial distribution through bottom-up modeling (Fig. 3). However, the top-down results show considerably larger sinks than the bottom-up results (Fig. 6). Replacing the 2004 version of GlobalView data with the 2005 version further increases the top-down sinks (Fig. 6). Theoretically, the 2005 version would match better with the setup of the transport model NIES, which uses the monthly average day-time mixed layer height to represent the transport within the mixed layer. However, we found that the low
Fig. 3. Net biome productivity (NBP) for Canada’s forests and wetlands averaged for the 1994-2003 period, simulated using InTEC at 1 km resolution in monthly time steps from 1901 to 2003. Note the correspondence of NBP with forest age shown in Fig. 2. Old forests are close to carbon neutral, young forests are carbon sources, and mid age (30-80 years old) forests are generally carbon sinks. Wetlands are carbon sinks. Climate change induced longer growing seasons and better nutrient conditions and hence larger sinks. These climate changes effects are so far stronger in the south than in the north.
b
Fig 2. Forest age map derived using forest inventory around 1990 (processed to 10 km resolution), large fire polygons from 1959 to 1996 (gridded to 1 km resolution), and fire scar and age detected using VEGETATION images in 1998 at 1 km resolution. This forest age map allows for the first order estimation of disturbance and regrowth.
References: Brenkert, A.L. 1998. Carbon dioxide emission estimates from fossil-fuel burning, hydraulic cement production, and gas flaring for 1995 on a one degree grid cell basis,http://cdiac.esd.ornl.gov/ndps/ndp058a.html, Carbon Dioxide Inf. Anal. Cent., Oak Ridge, Natl. Lab., Oak Ridge, Tenn.Deng, F., J. M. Chen, C.-W. Yuen, M. Ishizawa, G. Mo, K. Higuchi, D. Chan, B. Chen, and S. Maksyutov. 2007. Global monthly CO2 flux inversion with focus over North America. Tellus (in press). GLOBALVIEW-CO2: Cooperative Atmospheric Data Integration Project – Carbon Dioxide. CD-ROM, NOAA CMDL, Boulder, Colorado [Also available on Internet via anonymous FTP to ftp.cmdl.noaa.gov, Path: ccg/co2/GLOBALVIEW], 2005.Marland, G., T.A. Boden, and R. J. Andres. 2006. Global, Regional, and National CO2 Emissions. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A. Takahashi, T., R. Wanninkhof, R. A. Feely, et al. 1999. Net sea-air CO2 flux over the global oceans: An improved estimate based on the sea-air pCO2 difference, in Proceedings of the 2nd International Symposium on CO2 in the Oceans, the 12th global oceans: An improved estimate based on the sea-air pCO2 difference, in Proceedings of the 2en International Symposium on CO2 in the Oceans, the 12 th global environmental Tsujuba, 12-22 Jaanuary 1999, Tsukuba, Japan, 18-01, 4pp
Fig. 4. The annual net CO2 flux (NBP) of the 30 regions in North America, averaged for the 1994-2003 period.
Fig. 6. Year-by-year comparison of bottom-up and top-down NBP results. The 2005 version of the GlobalView data result in larger sinks than the 2004 version.
Acknowledgement:This research was supported by the Canadian Foundation for Climate and Atmospheric Sciences. From April 2007, it will become part of the Canadian Carbon Program. The availability of GlobalView dataset on the FTP site is greatly appreciated.
Decadal C Flux change of Canada's forests and wetlands
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
Flu
x (P
g C
/yr)
Top-down, GV04
Top-down, GV05
Bottom-up
Poster presented at the Joint North America Carbon Program meeting, Colorado Spring, January 25-26, 2007
2.3 Key Datasets• Globalview baseline station CO2 data + tall towers (2004 and 2005 versions, separately). 83 stations (Fig. 1)• Ocean carbon balance (Takahashi et al., 1999)• Global field of fossil fuel emission in 1995 (Brenkert, 1998), + national emission inventories in from 1995 to 2003 (Marland et al., 2006)• CASA NEP results averaged for 1994-2003 as the a priori for all years for bottom-up constraint
Fig. 5. The annual net CO2 flux (NBP) of the 50 regions of the globe, averaged for the 1994-2003 period, inverted using the 2004 version of the GlobalView data.
summer CO2 values over the continental sites in the 2005 version can induce even larger sinks if their errors are assumed to be the same as those in the 2004 version. In order to use the continental sites in the inversion in a compatible manner, a transport model that can resolve the diurnal mixed layer dynamics would be needed.
Environment EnvironnementCanada Canada
