Open AccessClimate‐driven exceedance of total (wet + dry) nitrogen (N) + sulfur (S) deposition to forest soil over the conterminous U.S
Author(s) -
Sun Jian,
Fu Joshua S.,
Lynch Jason A.,
Huang Kan,
Gao Yang
Publication year - 2017
Publication title -
earth's future
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.641
H-Index - 39
ISSN - 2328-4277
DOI - 10.1002/2017ef000588
Subject(s) - deposition (geology) , nitrogen , environmental science , soil water , climate change , hydrology (agriculture) , sulfur , atmospheric sciences , environmental chemistry , soil science , chemistry , ecology , geology , sediment , geomorphology , geotechnical engineering , organic chemistry , biology
Nitrogen (N) and sulfur (S) depositions are much mitigated over the conterminous U.S. ( CONUS ) but deposition exceedance still exists on forest soil. In addition, the empirical approach is usually used but only provides a spatially constant critical load ( CL ). Therefore, the CL derived from steady‐state mass balance equation is used to study the CL exceedance on forest soil over the CONUS . The multimodel mean ( MMM ) of global climate‐chemistry models in 2000s indicates that total (wet + dry) N deposition alone over 10.32% of forest soil exceeds the CL , but a higher percent (30.16%) is observed by the N + S deposition, which highlights the necessity of considering S deposition. In 2050s, less CL ‐exceeded forest soil is projected and the exceedance amount is lower as well, mainly attributed to the strong reduction of projected NO X and SO 2 emissions. By first projecting the future CL due to the climate change, the CL exceedance could further decrease as the air temperature is projected to increase rapidly and lead to higher CL in the future. The CL exceedance by N deposition alone is likely to be dominated by NO y in 2000s but NH X in 2050s because of the enhanced NH 3 emission. Moreover, both in 2000s and 2050s, using the CL generated by different aggregation methods can cause up to 33 times difference between the corresponding CL exceedance. This suggests that several regions are under the marginal threat of either N or N + S deposition and different CL can influence the results significantly.