Status report on the key climate variables technical supplement to the
Download 0.61 Mb.
|
- Navigate this page:
- Issues and priorities
- References
Current capabilityMost SOM values are derived from organic carbon (SOC) because the quantitative determination of SOM has high variability and questionable accuracy (Nelson and Sommers, 1982). Before data are compared or shared in a common database, the different methods have to be considered and possible calibrations considered. The most common procedures are: wet digestion, dry combustion and loss-on-ignition techniques. Another issue is that only rarely has any distinction been made between the three major SOM pools, yet most recent climate models distinguish these three pools, clearly limiting the use of such data. Future SOM data measurements need to consider these implications. Issues and priorities
ReferencesAjtay, G.L., P. Ketner and P. Duvigneaud (1979). Terrestrial primary production and phytomass. pp. 129-181 In: B. Bolin, E.T. Degnes, S. Kempe and P. Ketner, eds. The Global Carbon Cycle. Wiley, Chichester, UK. Amthor, J.S. (1995) Terrestrial higher-plant response to increasing atmospheric CO2 in relation to the global carbon cycle. Global Change Biology 1, 243-274. Amthor, J.S. and members of the Ecosystems Working Group (1998) Terrestrial Ecosystem Responses to Global Change: a research strategy. ORNL Technical Memorandum 1998/27, Oak Ridge National Laboratory, Oak Ridge, Tennessee. 37 pp. Borken, W., Xu, Y.-J., Davidson, E. A., and Beese, F. (2002) Site and temporal variation of soil respiration in European beech, Norway spruce, and Scots pine forests. Global Change Biology, 8, 1205-1216. Botkin, D.B. and L.G. Simpson (1990) Biomass of the North American boreal forest. Biogeochemistry 9, 161-174. FAO (1996) Production Yearbook, Volume 50. United Nations Food and Agriculture organization, Rome. Gallie, E.A. (1993). "Calibrating optical models of lake water colour using lab measurements - preliminary results." In The 16th Symposium on Remote Sensing, Sherbrooke, Que., 7-10 June, 1993: 119-123. Gallie, E.A. (1994). "Optical calibration parameters for water-colour models from Swan Lake, Northern Ontario." Canadian Journal of Remote Sensing, 20: 156-161. Gallie, E.A.( 1997). "Variation in the specific absorption of dissolved organic carbon in Northern Ontario lakes. Ocean optics XIII. Ed. by S.G. Ackleson and R. Frouin. In Proceedings of SPIE 2963: 417-422. Gorham, E. (1995) The biogeochemistry of northern peatlands and its possible responses to global warming. pp. 169-187. In: G.M. Woodwell and F.T. McKenzie, eds. Biotic Feedbacks in the Global Climate System. Oxford University Press, New York. Lieth, H.F.H. (1975) Primary production of the major vegetation units of the world. In: Primary Productivity of the Biosphere (H. Lieth, and R.H. Whittaker, eds.). Ecological Studies 14. Springer-Verlag, New York and Berlin. pp. 203-215. Nelson, D.W., & Sommers, L. E. (1982). Total carbon, organic carbon, and organic matter. In A. L. Page (Ed.), Methods of Soil Analysis. Part 2: Chemical and Microbiological Properties (pp. 539-580). Madison, WI: Soil Science Society of America. Nepstad, D.C., C.R. de Carvalho, E.A. Davidson, P.H. Jipp, P.A. Lefabvre, G.H. Negreiros, E.D. da Silva, T.A. Stone, S.E. Trumbore and S. Vieira (1994) The role of deep roots in the hydrological and carbon cycles of Amazonian forests and pastures. Nature 372, 666-669. Page, S.E., Siegert, F., Rieleys, J.O., Beohm, H.-D.V., Jaya, A., Limin, S. (2002) The amount of carbon released from peat and forest fires in Indonesia during 1997. Nature 420, 61-65. Parton W.J., Scurlock, J.M.O., Ojima, D.S., Schimel, D.S., Hall, D.O. and SCOPEGRAM Group Members (1995) Impact of climate change on grassland production and soil carbon world-wide. Global Change Biology 1, 13-22. Post, W. M., King, A. W., and S. D. Wullschleger 1996. Soil organic matter models and global estimates of soil organic carbon. pp. 201-222. In P. Smith, J. Smith and D. Powlson (eds.) Evaluation of Soil Organic Matter Models Using Existing Long-Term Datasets. Springer-Verlag, Berlin. Zinke P.J., Stangenburger A.G., Post W.M., Emmanuel W.R. & Olson J.S. (1984). World-wide organic soil carbon and nitrogen data. Environmental Sciences Division, publication no.2212. Oak Ridge National Lab/ US Department of Energy. Variable: Methane emissions Main climate application This is needed for climate change detection and estimation of national greenhouse gas (GHG) inventories. Methane is about 20 times more powerful than CO2, and global emissions are rising. The current direct radiative forcing of 0.48 Wm-2 from CH4 is 20% of the total from all of the long-lived and globally mixed GHGs. Terrestrial ecosystems account for about 70% of anthropogenic emissions, largely from irrigated rice (though now flattening off), ruminant production and biomass burning. There are large uncertainties about some present and future emissions, which constrain climate change detection, modelling and impact prediction. Contributing baseline GCOS observations No baseline GCOS observations but emissions are sensitive to temperature and precipitation so GCOS surface network important. Other contributing observations FAO soil map of the world and AEZ data. FAO AGROSTAT for land cover and land use data including rice area and ruminant numbers. IRRI for rice production systems. TOPC fire area and the Global Fire Product. IGBP experiments and programmes e.g. IGAC and LUCC. Significant data management issues Lack of agreed protocols. Analysis products Improved time series for emissions from rice and ruminants. Current capability Accuracy of present estimates is of the order of 50% (rice area generally 5%; ruminant numbers 5-25%; average emission factors 30-50%). There is some atmospheric monitoring through the NOAA/CMDL air sampling network. The International Rice Research Institute (IRRI) operates a network for methane from rice, but there is limited monitoring of methane from other wetlands/peatlands. Spatial and temporal aspects of vegetation fires can now be monitored well through the combination of different Earth observing systems/satellites and sensors but information gaps on the emission factors. Fairly close agreement between inverse modelling and inventory estimates but the latter suffer from large data uncertainties e.g. in amount of biomass burnt. Measurement of changes in isotope ratios in ice cores can estimate emission trends with high accuracy and a few sites can be representative of large regions of the globe. Issues and priorities
Variable: Non-C greenhouse gases emissions Directory: pages -> prog prog -> Regional Association IV (North America, Central America and the Caribbean) Hurricane Operational Plan prog -> Review of the ra IV hurricane operational plan prog -> Cyclone programme prog -> World meteorological organization prog -> World meteorological organization technical document prog -> Regional Association IV (North America, Central America and the Caribbean) Hurricane Operational Plan prog -> World meteorological organization ra IV hurricane committee thirty-fourth session prog -> World meteorological organization ra IV hurricane committee thirty-third session prog -> Review of the past hurricane season prog -> Ra IV hurricane committee thirty-fourth session ponte vedra beach, fl, usa Download 0.61 Mb. Share with your friends:
|