Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.5194/acp-17-8189-2017 |
Observation- and model-based estimates of particulate dry nitrogen deposition to the oceans | |
Baker, Alex R.1; Kanakidou, Maria2; Altieri, Katye E.3; Daskalakis, Nikos2; Okin, Gregory S.4; Myriokefalitakis, Stelios2,16; Dentener, Frank5; Uematsu, Mitsuo6; Sarin, Manmohan M.7; Duce, Robert A.8,9; Galloway, James N.10; Keene, William C.10; Singh, Arvind7; Zamora, Lauren11,12; Lamarque, Jean-Francois13; Hsu, Shih-Chieh14; Rohekar, Shital S.1,17; Prospero, Joseph M.15 | |
2017-07-05 | |
发表期刊 | ATMOSPHERIC CHEMISTRY AND PHYSICS
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ISSN | 1680-7316 |
EISSN | 1680-7324 |
出版年 | 2017 |
卷号 | 17期号:13 |
文章类型 | Article |
语种 | 英语 |
国家 | England; Greece; South Africa; USA; Italy; Japan; India; Taiwan; Netherlands |
英文摘要 | Anthropogenic nitrogen (N) emissions to the atmosphere have increased significantly the deposition of nitrate (NO3-) and ammonium (NH4+) to the surface waters of the open ocean, with potential impacts on marine productivity and the global carbon cycle. Global-scale understanding of the impacts of N deposition to the oceans is reliant on our ability to produce and validate models of nitrogen emission, atmospheric chemistry, transport and deposition. In this work, similar to 2900 observations of aerosol NO3- and NH4+ concentrations, acquired from sampling aboard ships in the period 1995-2012, are used to assess the performance of modelled N concentration and deposition fields over the remote ocean. Three ocean regions (the eastern tropical North Atlantic, the northern Indian Ocean and northwest Pacific) were selected, in which the density and distribution of observational data were considered sufficient to provide effective comparison to model products. All of these study regions are affected by transport and deposition of mineral dust, which alters the deposition of N, due to uptake of nitrogen oxides (NOx) on mineral surfaces. Assessment of the impacts of atmospheric N deposition on the ocean requires atmospheric chemical transport models to report deposition fluxes; however, these fluxes cannot be measured over the ocean. Modelling studies such as the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), which only report deposition flux, are therefore very difficult to validate for dry deposition. Here, the available observational data were averaged over a 5 degrees x 5 degrees grid and compared to ACCMIP dry deposition fluxes (Mod-Dep) of oxidised N (NOy) and reduced N (NHx) and to the following parameters from the Tracer Model 4 of the Environmental Chemical Processes Laboratory (TM4): ModDep for NOy, NHx and particulate NO3- and NH4+, and surface-level particulate NO3- and NH4+ concentrations. As a model ensemble, ACCMIP can be expected to be more robust than TM4, while TM4 gives access to speciated parameters (NO3- and NHC4+) that are more relevant to the observed parameters and which are not available in ACCMIP. Dry deposition fluxes (CalDep) were calculated from the observed concentrations using estimates of dry deposition velocities. Model-observation ratios (R-A,R-n), weighted by gridcell area and number of observations, were used to assess the performance of the models. Comparison in the three study regions suggests that TM4 overestimates NO3- concentrations (R-A,R-n = 1.4-2.9) and underestimates NH4+ concentrations (R-A,R-n = 0.5-0.7), with spatial distributions in the tropical Atlantic and northern Indian Ocean not being reproduced by the model. In the case of NH4+ in the Indian Ocean, this discrepancy was probably due to seasonal biases in the sampling. Similar patterns were observed in the various comparisons of CalDep to ModDep (R-A,R-n = 0.6-2.6 for NO3-, 0.6-3.1 for NH4+). Values of R-A,R-n for NHx CalDep-ModDep comparisons were approximately double the corresponding values for NH4+ CalDep-ModDep comparisons due to the significant fraction of gas-phase NH3 deposition incorporated in the TM4 and ACCMIP NHx model products. All of the comparisons suffered due to the scarcity of observational data and the large uncertainty in dry deposition velocities used to derive deposition fluxes from concentrations. These uncertainties have been a major limitation on estimates of the flux of material to the oceans for several decades. Recommendations are made for improvements in N deposition estimation through changes in observations, modelling and model-observation comparison procedures. Validation of modelled dry deposition requires effective comparisons to observable aerosol-phase species' concentrations, and this cannot be achieved if model products only report dry deposition flux over the ocean. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000404774700002 |
WOS关键词 | MINERAL DUST ; ATMOSPHERIC DEPOSITION ; TEMPORAL VARIABILITY ; MARINE AEROSOLS ; PACIFIC-OCEAN ; TRACE-METALS ; GLOBAL OCEAN ; NITRIC-ACID ; CHEMISTRY ; IRON |
WOS类目 | Environmental Sciences ; Meteorology & Atmospheric Sciences |
WOS研究方向 | Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/27285 |
专题 | 地球科学 |
作者单位 | 1.Univ East Anglia, Sch Environm Sci, Ctr Ocean & Atmospher Sci, Norwich, Norfolk, England; 2.Univ Crete, Dept Chem, Environm Chem Proc Lab, POB 2208, Iraklion, Greece; 3.Univ Cape Town, Dept Oceanog, Cape Town, South Africa; 4.Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90024 USA; 5.European Commiss, Joint Res Ctr, Ispra, Italy; 6.Univ Tokyo, Atmosphere & Ocean Res Inst, Ctr Int Collaborat, Chiba, Japan; 7.Phys Res Lab, Geosci Div, Ahmadabad, Gujarat, India; 8.Texas A&M Univ, Dept Oceanog, College Stn, TX 77843 USA; 9.Texas A&M Univ, Dept Atmospher Sci, College Stn, TX USA; 10.Univ Virginia, Dept Environm Sci, Clark Hall, Charlottesville, VA 22903 USA; 11.NASA, Goddard Space Flight Ctr, Climate & Radiat Lab, Greenbelt, MD USA; 12.Univ Maryland, ESSIC, College Pk, MD 20742 USA; 13.Natl Ctr Atmospher Res, NCAR Earth Syst Lab, POB 3000, Boulder, CO 80307 USA; 14.Acad Sinica, Res Ctr Environm Changes, Taipei, Taiwan; 15.Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, 4600 Rickenbacker Causeway, Miami, FL 33149 USA; 16.Univ Utrecht, IMAU, Utrecht, Netherlands; 17.Univ Hertfordshire, Sch Phys Astron & Maths, Hatfield, Herts, England |
推荐引用方式 GB/T 7714 | Baker, Alex R.,Kanakidou, Maria,Altieri, Katye E.,et al. Observation- and model-based estimates of particulate dry nitrogen deposition to the oceans[J]. ATMOSPHERIC CHEMISTRY AND PHYSICS,2017,17(13). |
APA | Baker, Alex R..,Kanakidou, Maria.,Altieri, Katye E..,Daskalakis, Nikos.,Okin, Gregory S..,...&Prospero, Joseph M..(2017).Observation- and model-based estimates of particulate dry nitrogen deposition to the oceans.ATMOSPHERIC CHEMISTRY AND PHYSICS,17(13). |
MLA | Baker, Alex R.,et al."Observation- and model-based estimates of particulate dry nitrogen deposition to the oceans".ATMOSPHERIC CHEMISTRY AND PHYSICS 17.13(2017). |
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