scholarly journals Modeling the biogeochemical impact of atmospheric phosphate deposition from desert dust and combustion sources to the Mediterranean Sea

2017 ◽  
Author(s):  
Camille Richon ◽  
Jean-Claude Dutay ◽  
François Dulac ◽  
Rong Wang ◽  
Yves Balkanski
Keyword(s):  
Mediterranean Sea ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Primary Source ◽  
Biogeochemical Model ◽  
Chemical Transport Model ◽  
Chl A ◽  
The North ◽  
The Mediterranean ◽  
The Impact

Abstract. We used phosphate deposition from natural dust, anthropogenic combustion and wildfires simulated for the year 2005 by a global atmospheric chemical transport model (LMDz–INCA) as additional sources of external nutrient for a high resolution regional coupled dynamical–biogeochemical model of the Mediterranean Sea. In general, dust is considered as the main atmospheric source of phosphorus, but the LMDz–INCA model suggests that combustion is dominant over natural dust as an atmospheric source of phosphate (the bioavailable form of phosphorus in seawater) for the Mediterranean Sea. According to the atmospheric transport model, anthropogenic phosphate deposition from combustion (Pcomb) brings on average 40.5 10−6 mol PO4 m−2 year−1 over the entire Mediterranean Sea for the year 2005 and is the primary source over the northern part (101 10−6 mol PO4 m−2 year−1 from combustion deposited in 2005 over the North Adriatic against 12.4 10−6 from dust). Lithogenic dust brings 17.2 10−6 mol PO4 m−2 year−1 on average over the Mediterranean Sea in 2005 and is the primary source of atmospheric phosphate to the southern Mediterranean basin in our simulations (31.8 10−6 mol PO4 m−2 year−1 from dust deposited in 2005 on average over the South Ionian basin against 12.4 10−6 from combustion). We examine separately the different soluble phosphorus (PO4) sources and their respective fluxes variability and evaluate their impacts on marine surface biogeochemistry (phosphate concentrations, Chl a, primary production). The impacts of the different phosphate deposition sources on the biogeochemistry of the Mediterranean are found localized, seasonally varying and small, but yet statistically significant. The impact of the different sources of phosphate on the biogeochemical cycles is remarkably different and should be accounted for in modeling studies.

scholarly journals Modeling the biogeochemical impact of atmospheric phosphate deposition from desert dust and combustion sources to the Mediterranean Sea

2018 ◽  
Vol 15 (8) ◽  
pp. 2499-2524 ◽  
Author(s):  
Camille Richon ◽  
Jean-Claude Dutay ◽  
François Dulac ◽  
Rong Wang ◽  
Yves Balkanski
Keyword(s):  
Mediterranean Sea ◽  
Transport Model ◽  
Source Region ◽  
Primary Source ◽  
Biogeochemical Model ◽  
Deposition Flux ◽  
Chemical Transport Model ◽  
Northern Adriatic ◽  
Flux Variability ◽  
The Mediterranean

Abstract. Daily modeled fields of phosphate deposition to the Mediterranean from natural dust, anthropogenic combustion and wildfires were used to assess the effect of this external nutrient on marine biogeochemistry. The ocean model used is a high-resolution (1∕12°) regional coupled dynamical–biogeochemical model of the Mediterranean Sea (NEMO-MED12/PISCES). The input fields of phosphorus are for 2005, which are the only available daily resolved deposition fields from the global atmospheric chemical transport model LMDz-INCA. Traditionally, dust has been suggested to be the main atmospheric source of phosphorus, but the LMDz-INCA model suggests that combustion is dominant over natural dust as an atmospheric source of phosphate (PO4, the bioavailable form of phosphorus in seawater) for the Mediterranean Sea. According to the atmospheric transport model, phosphate deposition from combustion (Pcomb) brings on average 40.5×10−6 mol PO4 m−2 yr−1 over the entire Mediterranean Sea for the year 2005 and is the primary source over the northern part (e.g., 101×10−6 mol PO4 m−2 yr−1 from combustion deposited in 2005 over the north Adriatic against 12.4×10−6 from dust). Lithogenic dust brings 17.2×10−6 mol PO4 m−2 yr−1 on average over the Mediterranean Sea in 2005 and is the primary source of atmospheric phosphate to the southern Mediterranean Basin in our simulations (e.g., 31.8×10−6 mol PO4 m−2 yr−1 from dust deposited in 2005 on average over the south Ionian basin against 12.4×10−6 from combustion). The evaluation of monthly averaged deposition flux variability of Pdust and Pcomb for the 1997–2012 period indicates that these conclusions may hold true for different years. We examine separately the two atmospheric phosphate sources and their respective flux variability and evaluate their impacts on marine surface biogeochemistry (phosphate concentration, chlorophyll a, primary production). The impacts of the different phosphate deposition sources on the biogeochemistry of the Mediterranean are found localized, seasonally varying and small, but yet statistically significant. Differences in the geographical deposition patterns between phosphate from dust and from combustion will cause contrasted and significant changes in the biogeochemistry of the basin. We contrast the effects of combustion in the northern basin (Pcomb deposition effects are found to be 10 times more important in the northern Adriatic, close to the main source region) to the effects of dust in the southern basin. These different phosphorus sources should therefore be accounted for in modeling studies.

scholarly journals Impact of air–sea coupling on the climate change signal over the Iberian Peninsula

2021 ◽  
Author(s):  
Alba de la Vara ◽  
William Cabos ◽  
Dmitry V. Sein ◽  
Claas Teichmann ◽  
Daniela Jacob
Keyword(s):  
Climate Change ◽  
Iberian Peninsula ◽  
Mediterranean Sea ◽  
Large Scale ◽  
Regional Distribution ◽  
Coupled Model ◽  
Climate Change Signal ◽  
The North ◽  
The Mediterranean ◽  
The Impact

AbstractIn this work we use a regional atmosphere–ocean coupled model (RAOCM) and its stand-alone atmospheric component to gain insight into the impact of atmosphere–ocean coupling on the climate change signal over the Iberian Peninsula (IP). The IP climate is influenced by both the Atlantic Ocean and the Mediterranean sea. Complex interactions with the orography take place there and high-resolution models are required to realistically reproduce its current and future climate. We find that under the RCP8.5 scenario, the generalized 2-m air temperature (T2M) increase by the end of the twenty-first century (2070–2099) in the atmospheric-only simulation is tempered by the coupling. The impact of coupling is specially seen in summer, when the warming is stronger. Precipitation shows regionally-dependent changes in winter, whilst a drier climate is found in summer. The coupling generally reduces the magnitude of the changes. Differences in T2M and precipitation between the coupled and uncoupled simulations are caused by changes in the Atlantic large-scale circulation and in the Mediterranean Sea. Additionally, the differences in projected changes of T2M and precipitation with the RAOCM under the RCP8.5 and RCP4.5 scenarios are tackled. Results show that in winter and summer T2M increases less and precipitation changes are of a smaller magnitude with the RCP4.5. Whilst in summer changes present a similar regional distribution in both runs, in winter there are some differences in the NW of the IP due to differences in the North Atlantic circulation. The differences in the climate change signal from the RAOCM and the driving Global Coupled Model show that regionalization has an effect in terms of higher resolution over the land and ocean.

scholarly journals Influences of hydroxyl radicals (OH) on top-down estimates of the global and regional methane budgets

2020 ◽  
Author(s):  
Yuanhong Zhao ◽  
Marielle Saunois ◽  
Philippe Bousquet ◽  
Xin Lin ◽  
Antoine Berchet ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Climate Models ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Temporal Variations ◽  
Oh Radicals ◽  
Chemical Transport Model ◽  
Top Down ◽  
Ch4 Emissions ◽  
The Impact

Abstract. The hydroxyl radical (OH), which is the dominant sink of methane (CH4), plays a key role to close the global methane budget. Previous research that assessed the impact of OH changes on the CH4 budget mostly relied on box modeling inversions with a very simplified atmospheric transport and no representation of the heterogeneous spatial distribution of OH radicals. Here using a variational Bayesian inversion framework and a 3D chemical transport model, LMDz, combined with 10 different OH fields derived from chemistry-climate models (CCMI experiment), we evaluate the influence of OH burden, spatial distribution, and temporal variations on the global CH4 budget. The global tropospheric mean CH4-reaction-weighted [OH] ([OH]GM-CH4) ranges 10.3–16.3 × 105 molec cm−3 across 10 OH fields during the early 2000s, resulting in inversion-based global CH4 emissions between 518 and 757 Tg yr−1. The uncertainties in CH4 inversions induced by the different OH fields are comparable to, or even larger than the uncertainty typically given by bottom-up and top-down estimates. Based on the LMDz inversions, we estimate that a 1 %-increase in OH burden leads to an increase of 4 Tg yr−1 in the estimate of global methane emissions, which is about 25 % smaller than what is estimated by box-models. The uncertainties in emissions induced by OH are largest over South America, corresponding to large inter-model differences of [OH] in this region. From the early to the late 2000s, the optimized CH4 emissions increased by 21.9 ± 5.7 Tg yr−1 (16.6–30.0 Tg yr−1), of which ~ 25 % (on average) is contributed by −0.5 to +1.8 % increase in OH burden. If the CCMI models represent the OH trend properly over the 2000s, our results show that a higher increasing trend of CH4 emissions is needed to match the CH4 observations compared to the CH4 emission trend derived using constant OH. This study strengthens the importance to reach a better representation of OH burden and of OH spatial and temporal distributions to reduce the uncertainties on the global CH4 budget.

scholarly journals Oxygen budget of the north-western Mediterranean deep- convection region

2021 ◽  
Vol 18 (3) ◽  
pp. 937-960
Author(s):  
Caroline Ulses ◽  
Claude Estournel ◽  
Marine Fourrier ◽  
Laurent Coppola ◽  
Fayçal Kessouri ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Mediterranean Sea ◽  
Atmospheric Oxygen ◽  
Deep Convection ◽  
Western Mediterranean ◽  
Biogeochemical Model ◽  
The North ◽  
Oxygen Budget ◽  
The Mediterranean ◽  
North Western

Abstract. The north-western Mediterranean deep convection plays a crucial role in the general circulation and biogeochemical cycles of the Mediterranean Sea. The DEWEX (DEnse Water EXperiment) project aimed to better understand this role through an intensive observation platform combined with a modelling framework. We developed a three-dimensional coupled physical and biogeochemical model to estimate the cycling and budget of dissolved oxygen in the entire north-western Mediterranean deep-convection area over the period September 2012 to September 2013. After showing that the simulated dissolved oxygen concentrations are in a good agreement with the in situ data collected from research cruises and Argo floats, we analyse the seasonal cycle of the air–sea oxygen exchanges, as well as physical and biogeochemical oxygen fluxes, and we estimate an annual oxygen budget. Our study indicates that the annual air-to-sea fluxes in the deep-convection area amounted to 20 molm-2yr-1. A total of 88 % of the annual uptake of atmospheric oxygen, i.e. 18 mol m−2, occurred during the intense vertical mixing period. The model shows that an amount of 27 mol m−2 of oxygen, injected at the sea surface and produced through photosynthesis, was transferred under the euphotic layer, mainly during deep convection. An amount of 20 mol m−2 of oxygen was then gradually exported in the aphotic layers to the south and west of the western basin, notably, through the spreading of dense waters recently formed. The decline in the deep-convection intensity in this region predicted by the end of the century in recent projections may have important consequences on the overall uptake of atmospheric oxygen in the Mediterranean Sea and on the oxygen exchanges with the Atlantic Ocean, which appear necessary to better quantify in the context of the expansion of low-oxygen zones.

scholarly journals The Expected Impact of Marine Energy Farms Operating in Island Environments with Mild Wave Energy Resources—A Case Study in the Mediterranean Sea

Inventions ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 33
Author(s):  
Liliana Rusu ◽  
Florin Onea ◽  
Eugen Rusu
Keyword(s):  
Mediterranean Sea ◽  
Wind Turbines ◽  
Electricity Production ◽  
Time Interval ◽  
Target Area ◽  
Sea State ◽  
The North ◽  
Marine Energy ◽  
The Mediterranean ◽  
The Impact

A particularity of island areas is that they are subjected to strong sea state conditions that can have a severe impact on the beach stability, while on the other hand, they rely mainly on diesel combustion for electricity production which in the long run is not a sustainable solution. The aim of this work is to tackle these two issues, by assessing the impact of a hybrid marine energy farm that may operate near the north-western part of Giglio Island in the Mediterranean Sea. As a first step, the most relevant environmental conditions (wind and waves) over a 27-year time interval (January 1992–December 2018) were identified considering data coming from both ERA5 and the European Space Agency Climate Change Initiative for Sea State. An overview of the electricity production was made by considering some offshore wind turbines, the results showing that even during the summertime when there is a peak demand (but low wind resources), the demand can be fully covered by five wind turbines defined each by a rated power of 6 MW. The main objective of this work is to assess the coastal impact induced by a marine energy farm, and for this reason, various layouts obtained by varying the number of lines (one or two) and the distance between the devices were proposed. The modelling system considered has been already calibrated in the target area for this type of study while the selected device is defined by a relatively low absorption property. The dynamics of various wave parameters has been analysed, including significant wave height, but also parameters related to the breaking mechanics, and longshore currents. It was noticed that although the target area is naturally protected by the dominant waves that are coming from the south-western sector, it is possible to occur extreme waves coming from the north-west during the wintertime that can be efficiently attenuated by the presence of the marine energy farm.

scholarly journals Oxygen budget for the north-western Mediterranean deep convection region

2020 ◽  
Author(s):  
Caroline Ulses ◽  
Claude Estournel ◽  
Marine Fourrier ◽  
Laurent Coppola ◽  
Fayçal Kessouri ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Mediterranean Sea ◽  
Atmospheric Oxygen ◽  
Deep Convection ◽  
Western Mediterranean ◽  
Biogeochemical Model ◽  
The North ◽  
Oxygen Budget ◽  
The Mediterranean ◽  
North Western

Abstract. The north-western Mediterranean deep convection plays a crucial role in the general circulation and biogeochemical cycles of the Mediterranean Sea. The DEWEX (DEnse Water EXperiment) project aimed to better understand this role through an intensive observation platform combined with a modelling framework. We developed a 3 dimensional coupled physical and biogeochemical model to estimate the cycling and budget of dissolved oxygen in the entire north-western Mediterranean deep convection area over the period September 2012 to September 2013. After showing that the simulated dissolved oxygen concentrations are in a good agreement with the in situ data collected from research cruises and Argo floats, we analyze the seasonal cycle of the air-sea oxygen exchanges, as well as physical and biological oxygen fluxes, and we estimate an annual oxygen budget. Our study indicates that the annual air-to-sea fluxes in the deep convection area amounted to 20 mol m−2 yr−1. 88 % of the annual uptake of atmospheric oxygen, i.e. 18 mol m−2, occurred during the intense vertical mixing period. The model shows that an amount of 27 mol m−2 of oxygen, injected at the sea surface and produced through photosynthesis, was transferred under the euphotic layer, mainly during deep convection. An amount of 20 mol m−2 of oxygen was then gradually exported in the aphotic layers to the south and west of the western basin, notably, through the spreading of dense waters recently formed. The decline in the deep convection intensity in this region predicted by the end of the century in recent projections, may have important consequences on the overall uptake of atmospheric oxygen in the Mediterranean Sea and on the oxygen exchanges with the Atlantic Ocean, that appear necessary to better quantify in the context of the expansion of low-oxygen zones.

scholarly journals New constraints on terrestrial and oceanic sources of atmospheric methanol

2008 ◽  
Vol 8 (2) ◽  
pp. 7609-7655 ◽  
Author(s):  
D. B. Millet ◽  
D. J. Jacob ◽  
T. G. Custer ◽  
J. A. de Gouw ◽  
A. H. Goldstein ◽  
...  
Keyword(s):  
Transport Model ◽  
Primary Source ◽  
Anthropogenic Source ◽  
Aircraft Measurements ◽  
Terrestrial Plants ◽  
Chemical Transport Model ◽  
Plant Source ◽  
The North ◽  
Broadleaf Tree ◽  
Surface Measurements

Abstract. We use a global 3-D chemical transport model (GEOS-Chem) to interpret new aircraft, surface, and oceanic observations of methanol in terms of the constraints that they place on the atmospheric methanol budget. Recent measurements of methanol concentrations in the ocean mixed layer (OML) imply that in situ biological production must be the main methanol source in the OML, dominating over uptake from the atmosphere. It follows that oceanic emission and uptake must be viewed as independent terms in the atmospheric methanol budget. We deduce that the marine biosphere is a large primary source (85 Tg y−1) of methanol to the atmosphere and is also a large sink (101 Tg y−1), comparable in magnitude to atmospheric oxidation by OH (88 Tg y−1). The resulting atmospheric lifetime of methanol in the model is 4.7 days. Aircraft measurements in the North American boundary layer imply that terrestrial plants are a much weaker source than presently thought, likely reflecting an overestimate of broadleaf tree emissions, and this is also generally consistent with surface measurements. We deduce a terrestrial plant source of 80 Tg y−1, comparable in magnitude to the ocean source. The aircraft measurements show a strong correlation with CO (R2=0.51–0.61). We reproduce this correlation in the model with the reduced plant source, which also confirms that the anthropogenic source of methanol must be small. Our reduced plant source also provides a better simulation of methanol observations over tropical South America.

scholarly journals The impact of multi-species surface chemical observations assimilation on the air quality forecasts in China

2018 ◽  
Author(s):  
Zhen Peng ◽  
Lili Lei ◽  
Zhiquan Liu ◽  
Jianning Sun ◽  
Aijun Ding ◽  
...  
Keyword(s):  
Air Quality ◽  
Transport Model ◽  
Initial Conditions ◽  
Yangtze River Delta ◽  
River Delta ◽  
Chemical Transport Model ◽  
The North ◽  
Surface Measurements ◽  
Haze Episode ◽  
The Impact

Abstract. An Ensemble Kalman Filter data assimilation (DA) system has been developed to improve air quality forecasts using surface measurements of PM10, PM2.5, SO2, NO2, O3 and CO together with an online regional chemical transport model, WRF-Chem (Weather Research and Forecasting with Chemistry). This DA system was applied to simultaneously adjust the chemical initial conditions (ICs) and emission inputs of the species affecting PM10, PM2.5, SO2, NO2, O3 and CO concentrations during an extreme haze episode that occurred in early October 2014 over the North China Plain. Numerical experimental results indicate that ICs play key roles in PM2.5, PM10 and CO forecasts during the severe haze episode. The 72-h verification forecasts with the optimized ICs and emissions performed very similarly to the verification forecasts with only optimized ICs and the prescribed emissions. For the first-day forecast, near perfect verification forecasts results were achieved. However, with longer range forecasts, the DA impacts decayed quickly. For the SO2 verification forecasts, it was efficient to improve the SO2 forecast via the joint adjustment of SO2 ICs and emissions. Large improvements were achieved for SO2 forecasts with both the optimized ICs and emissions for the whole 72-h forecast range. Similar improvements were achieved for SO2 forecasts with optimized ICs only for just the first 3 h, and then the impact of the ICs decayed quickly. For the NO2 verification forecasts, both forecasts performed much worse than the control run without DA. Plus, the 72-h O3 verification forecasts performed worse than the control run during the daytime, due to the worse performance of the NO2 forecasts, even though they performed better at night. However, relatively favorable NO2 and O3 forecast results were achieved for the Yangtze River delta and Pearl River delta regions.

scholarly journals THE IMPACT OF PRECIPITATION ON WET DEPOSITION OF SULPHUR AND NITROGEN COMPOUNDS

2013 ◽  
Vol 20 (4) ◽  
pp. 733-745 ◽  
Author(s):  
Kinga Wałaszek ◽  
Maciej Kryza ◽  
Anthony J. Dore
Keyword(s):  
Wet Deposition ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Annual Precipitation ◽  
Mean Annual Precipitation ◽  
Emission Data ◽  
The North ◽  
Reduced Nitrogen ◽  
Deposition Of Pollutants ◽  
The Impact

Abstract Atmospheric transport model FRAME has been used in this study to estimate the influence of precipitation on the patterns of wet deposition of oxidised sulphur, oxidised nitrogen and reduced nitrogen in Poland during the years 1981-2005. A constant wind and emission data and year-specific spatially interpolated precipitation data was used in the model. The results show that the correlation coefficient between mean annual precipitation totals and mean wet deposition is above 0.9 for all examined compounds. The spatial patterns of pollutant deposition are similar for all years, with the north-western part of Poland receiving the lowest and the southern, mountainous part, the highest pollutant load. The largest precipitation-induced changes in wet deposition budgets are observed for oxidised sulphur (53% of the average amount between wet and dry year), and smaller for oxidised and reduced nitrogen (30%). Inter-annual precipitation changes cause large variations in the amount of wet deposition of pollutants. This means that the emission abatements may not cause immediate environmental effects, eg reductions in deposition of pollutants and, further ecosystems areas of exceeded critical loads.

scholarly journals New constraints on terrestrial and oceanic sources of atmospheric methanol

2008 ◽  
Vol 8 (23) ◽  
pp. 6887-6905 ◽  
Author(s):  
D. B. Millet ◽  
D. J. Jacob ◽  
T. G. Custer ◽  
J. A. de Gouw ◽  
A. H. Goldstein ◽  
...  
Keyword(s):  
Transport Model ◽  
Primary Source ◽  
Anthropogenic Source ◽  
Aircraft Measurements ◽  
Terrestrial Plants ◽  
Chemical Transport Model ◽  
Plant Source ◽  
The North ◽  
Broadleaf Tree ◽  
Surface Measurements

Abstract. We use a global 3-D chemical transport model (GEOS-Chem) to interpret new aircraft, surface, and oceanic observations of methanol in terms of the constraints that they place on the atmospheric methanol budget. Recent measurements of methanol concentrations in the ocean mixed layer (OML) imply that in situ biological production must be the main methanol source in the OML, dominating over uptake from the atmosphere. It follows that oceanic emission and uptake must be viewed as independent terms in the atmospheric methanol budget. We deduce that the marine biosphere is a large primary source (85 Tg a−1) of methanol to the atmosphere and is also a large sink (101 Tg a−1), comparable in magnitude to atmospheric oxidation by OH (88 Tg a−1). The resulting atmospheric lifetime of methanol in the model is 4.7 days. Aircraft measurements in the North American boundary layer imply that terrestrial plants are a much weaker source than presently thought, likely reflecting an overestimate of broadleaf tree emissions, and this is also generally consistent with surface measurements. We deduce a terrestrial plant source of 80 Tg a−1, comparable in magnitude to the ocean source. The aircraft measurements show a strong correlation with CO (R2=0.51−0.61) over North America during summer. We reproduce this correlation and slope in the model with the reduced plant source, which also confirms that the anthropogenic source of methanol must be small. Our reduced plant source also provides a better simulation of methanol observations over tropical South America.

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