Improved vegetation distribution and emission data for Africa south of the equator were developed for the Southern African Regional Science Initiative (SAFARI 2000) and combined with biogenic volatile organic compound (BVOC) emission measurements to estimate BVOC emissions for the southern African region. BVOC emissions were estimated for southern Africa on a monthly basis over a one-year period by combining GIS layers of vegetation, LAI, and climate with a biogenic emissions model, GLOBEIS (Guenther et al., 1993; Guenther, 1999). Model input data included: vegetation data (Rutherford et al., 2000); species emission capacity data (Greenberg et al., 2003; Guenther et al., 1996; Harley et al., 2003; Klinger et al., 1998; Otter et al., 2002; Serca et al., 2001; Wiedinmyer et al., 2004); LAI data (1987-88 ISLSCP LAI; Sellers et al., 1994); cloud cover (MODIS LAI cloud mask); and temperature data (NOAA NCDC data).
Model output includes emissions estimates for isoprene, light-dependent monoterpene, stored monoterpene, and other volatile organic compounds by land cover category and by vegetation type (g C m-2 mo-1). Emissions were modeled for a summer (January) and a winter (July) month in 2001. Monthly and annual total emissions per constituent for the year 2001 were also calculated.
The data files containing the model outputs are ASCII comma-delimited files. Graphics (.jpgs) included with this data set show the distribution of light dependent monoterpene emissions across southern Africa during January, the average monthly isoprene emissions over southern Africa in January and in July, and the average monthly stored monoterpene emissions over southern Africa in January and in July.
Cite this data set as follows:
Otter, L. 2004. SAFARI 2000 Estimated BVOC Emissions for Southern African Land Cover Types. Data set. Available on-line [http://daac.ornl.gov/] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/764.
Greenberg, J. P., A. Guenther, P. Harley, L. Otter, E. M. Veenendaal, C. N. Hewitt, A. E. James, and S. M. Owen. 2003. Eddy flux and leaf-level measurements of biogenic VOC emissions from mopane woodland of Botswana. J. Geophys. Res., 108(D13): 8466, doi:10.1029/2002JD002317.
Guenther, A., P. Zimmerman, P. Harley, R. Monson, and R. Fall. 1993. Isoprene and monoterpene emission rate variability: Model evaluation and sensitivity analysis. J. Geophys. Res., 98: 12609-12617.
Guenther, A. 1999. Modeling biogenic volatile organic compound emissions to the atmosphere. In: Hewitt, C. N. (ed.). Reactive Hydrocarbons in the Atmosphere, pp. 97-118. Academic Press, California.
Guenther, A., L. B. Otter, P. Zimmerman, J. Greenberg, R. Scholes, and M. C. Scholes. 1996. Biogenic hydrocarbon emissions from southern Africa savannas. J. Geophys. Res., 101: 25,859-25,865.
Harley, P., L. Otter, A. Guenther, and J. Greenberg. 2003. Micrometeorological and leaf-level measurements of isoprene emissions from a southern African savanna. J. Geophys. Res., 108(D13), 8468, doi:10.1029/2002JD002592.
Klinger, L. F., J. Greenberg, A. Guenther, G. Tyndall, P. Zimmerman, M. M'Bangui, J. M. Moutsambote, and D. Kenfack. 1998. Patterns of volatile organic compound emissions along a savanna-rainforest gradient in central Africa. J. Geophys. Res., 103: 1443-1454.
Otter, L. B., A. Guenther, and J. Greenberg. 2002. Seasonal and spatial variations in biogenic hydrocarbon emissions from southern African savannas and woodland. Atmos. Environ., 36: 4265-4275.
Otter, L., A. Guenther, C. Wiedinmyer, G. Fleming, P. Harley, and J. Greenberg. 2003. Spatial and temporal variations in biogenic volatile organic compound emissions for Africa south of the equator. J. Geophys. Res., 108(D13), 8505, doi:10.1029/2002JD002609.
Rutherford, M. C., P. O'Farrel, K. Goldberg, G. F. Midgley, L. W. Powrie, S. Ringrose, W. Mattheson, and J. Timberlake. 2000. SAFARI 2000: Sub-project 6: Species composition of southern African vegetation, NBI Report. National Botanical Institute, Claremont, South Africa.
Sellers, P. J., C. O. Los, C. J. Tucker, C. O. Justice, D. A. Dazlich, G. J. Collatz, and D. A. Randall. 1994. A global 1 by 1 degree NDVI data set for climate studies, 2. The generation of global fields of terrestrial biophysical parameters from the NDVI. Int. J. Remote Sens., 15: 3519-3545.
Serca, D., A. Guenther, L. Klinger, L. Vierling, P. Harley, A. Druilhet, J. Greenberg, B. Baker, W. Baugh, C. Bouka-Biona, and J. Loemba-Ndembi. 2001. EXPRESSO flux measurements at upland and lowland Congo tropical forest site. Tellus, 53B: 220-234.
Wiedinmyer, C., A. Guenther, P. Harley, C. N. Hewitt, C. Geron, P. Artaxo, R. Steinbrecher, R., and Rasmussen. 2004. Global organic emissions from vegetation. IN: Granier, C., P. Artaxo, and C. E. Reeves (eds.). Emissions of Atmospheric Trace Compounds, pp. 115-170. Kluwer Academic Publishers, Dordrecht, The Netherlands.
Model output includes files of isoprene, light-dependent monoterpene, stored monoterpene, and other VOC emissions by land use category and vegetation type. Emissions were modeled for a summer (January) and a winter (July) month. Annual and monthly estimates were also calculated. The data files are ASCII comma-delimited files. This data set includes the following files:
annual&monthly_emissions.csv
bvoc_emissions_by_landcover.csv
land_use_emissions.csv
The annual&monthly_emissions.csv data file contains the following columns of data. In addition, it contains the annual total emissions per constituent.
| Column | Description | Units |
|---|---|---|
| Month | Month of Estimate | month |
| Iso | Isoprene Emissions | g C m-2 mo-1 |
| LDMT | Light-dependent monoterpene emissions | g C m-2 mo-1 |
| SMT | Stored monoterpene emissions | g C m-2 mo-1 |
| OVOC | Other VOC emissions | g C m-2 mo-1 |
| LAI | Leaf Area Index | m2 m-2 |
| Temp | Air Temperature | degrees C |
The bvoc_emissions_by_landcover.csv data file contains BVOC emissions estimates for the different vegetation types on the NBI vegetation map (Rutherford et al., 2000) for the study area. The following table describes the contents of the data file:
| Column | Description | Units |
|---|---|---|
| Code | Vegetation type code | numeric |
| NBI Code | Code from NBI map | alphanumeric |
| Description | NBI Map Description of Vegetation | ASCII |
| Ann Iso | Annual Emissions of Isoprene | g C m-2 yr-1 |
| Ann LDMT | Annual Emissions of Light-dependent monoterpenes | g C m-2 yr-1 |
| Ann SMT | Annual Emissions of stored monoterpenes | g C m-2 yr-1 |
| Ann OVOC | Annual Emissions of other VOCs | g C m-2 yr-1 |
| Iso Jan | Isoprene Emissions January 2001 | g C m-2 mo-1 |
| LDMT Jan | Light-dependent monoterpene emissions January 2001 | g C m-2 mo-1 |
| SMT Jan | Stored monoterpene emissions January 2001 | g C m-2 mo-1 |
| OVOC Jan | Other VOC emissions January 2001 | g C m-2 mo-1 |
| Iso Jul | Isoprene Emissions July 2001 | g C m-2 mo-1 |
| LDMT Jul | Light-dependent monoterpene emissions July 2001 | g C m-2 mo-1 |
| SMT Jul | Stored monoterpene emissions July 2001 | g C m-2 mo-1 |
| OVOC Jul | Other VOC emissions July 2001 | g C m-2 mo-1 |
The land_use_emissions.csv file contains contains BVOC emissions estimates for generalized land use and land cover categories in the study area. The following table describes the contents of the data file:
| Column | Description | Units |
|---|---|---|
| Land cover | Generalized land use categories | ASCII |
| Iso Jan | Isoprene Emissions January 2001 | g C m-2 yr-1 |
| LDMT Jan | Light-dependent monoterpene emissions January 2001 | g C m-2 yr-1 |
| SMT Jan | Stored monoterpene emissions January 2001 | g C m-2 yr-1 |
| OVOC Jan | Other VOC emissions January 2001 | g C m-2 yr-1 |
| Total BVOC Jan | Total Biogenic VOC emissions January 2001 | g C m-2 yr-1 |
| Iso Jul | Isoprene Emissions July 2001 | g C m-2 yr-1 |
| LDMT Jul | Light-dependent monoterpene emissions July 2001 | g C m-2 yr-1 |
| SMT Jul | Stored monoterpene emissions July 2001 | g C m-2 yr-1 |
| OVOC Jul | Other VOC emissions July 2001 | g C m-2 yr-1 |
| Total BVOC July | Total Biogenic VOC emissions July 2001 | g C m-2 yr-1 |
Additional graphics are included with the data:
| File Names | Description |
|---|---|
| bvoc_fig1.jpg | Distribution of light dependent monoterpene emissions across southern Africa during January (g C m-2 month-1). White areas indicate no emissions. |
| bvoc_fig2a.jpg | Average monthly isoprene emissions (g C m-2 month-1) over southern Africa in January. |
| bvoc_fig2b.jpg | Average monthly isoprene emissions (g C m-2 month-1) over southern Africa in July. |
| bvoc_fig2c.jpg | Average monthly 'stored' monoterpene emissions (g C m-2 month-1) over southern Africa in January. |
| bvoc_fig2d.jpg | Average monthly 'stored' monoterpene emissions (g C m-2 month-1) over southern Africa in July. |
Additional information about the GLOBEIS model and input data, BVOC emissions modeling results, and data file format is found in the following companion file: http://daac.ornl.gov/daacdata/safari2k/regional/landcover_bvoc_est/comp/landcover_bvoc_est_readme.pdf
2004/9/29
2004/9/29
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