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A global inventory of N 2 O emissions from tropical rainforest soils using a detailed biogeochemical model
Author(s) -
Werner C.,
ButterbachBahl K.,
Haas E.,
Hickler T.,
Kiese R.
Publication year - 2007
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2006gb002909
Subject(s) - rainforest , biogeochemical cycle , environmental science , biosphere , soil water , atmospheric sciences , tropics , tropical rainforest , ecosystem , hydrology (agriculture) , climatology , soil science , ecology , geology , biology , geotechnical engineering
Beside agricultural soils, tropical rainforest soils are the main source of atmospheric N 2 O. Current estimates of the global N 2 O source strength of tropical rainforest soils are still based on rather simplistic upscaling approaches and do have a large range of uncertainty. In this study, the biogeochemical ForestDNDC‐tropica model was recalibrated and intensively tested on the site scale prior to inventory calculations. For this, the model was coupled to a newly developed global GIS database holding relevant information on model initialization and driving parameters in 0.25° × 0.25° resolution. On average, the mean annual N 2 O emission source strength of rainforests ecosystems worldwide for the 10‐year‐period 1991–2000 was calculated to be 1.2 kg N 2 O‐N ha −1 yr −1 . Using a total rainforest area of 10.9 × 10 6 km 2 , this amounts to a total source strength of 1.34 Tg N yr −1 . The result of an initialization parameter uncertainty assessment using Latin Hypercube sampling revealed that the global source strength of N 2 O emissions from tropical rainforests may range from 0.88 to 2.37 Tg N yr −1 . Our calculations also show that N 2 O emissions do vary substantially on spatial and temporal scales. Regional differences were mainly caused by differences in soil properties, whereas the pronounced seasonal and interannual variability was driven by climate variability. Our work shows that detailed biogeochemical models are a valuable tool for assessing biosphere‐atmosphere exchange even on a global scale. However, further progress and a narrowing of the uncertainty range do crucially depend on the availability of more detailed field measurements for model testing and an improvement of the quality of spatial data sets on soil and vegetation properties.