Figure - available from: Global Biogeochemical Cycles
This content is subject to copyright. Terms and conditions apply.
Mean annual precipitation (MAP, mm yr⁻¹) determines the direction and strength of the correlation between mean monthly precipitation and (a) mean monthly tropospheric nitrogen dioxide (NO2) vertical column density (VCD) (2005–2017) and (b) mean monthly atmospheric ammonia (NH3) VCD (2008–2017) for 0.25° grid cells over all of continental Africa. Precipitation values are from Tropical Rainfall Measuring Mission, and NO2 and NH3 data are from Ozone Monitoring Instrument and Infrared Atmospheric Sounding Interferometer, respectively. Lighter shades of copper represent a higher density of grid cells.
Source publication
Ammonia (NH3) and nitrogen oxides (NOx: nitrogen dioxide [NO2] + nitric oxide [NO]) play important roles in atmospheric chemistry. Throughout most of Africa, emissions of these gases are predominantly from soils and biomass burning. Here we use observations of tropospheric NO2 vertical column densities (VCDs) from the Ozone Monitoring Instrument fr...
Similar publications
The tropospheric hydroxyl radical (TOH) is a key player in regulating oxidation of various compounds in Earth’s atmosphere. Despite its pivotal role, the spatiotemporal distributions of OH are poorly constrained. Past modeling studies suggest that the main drivers of OH, including NO2, tropospheric ozone (TO3), and H2O(v), have increased TOH global...
Ozone (O3), an important and ubiquitous trace gas, protects lives from harm of solar ultraviolet (UV) radiation in the stratosphere but is toxic to living organisms in the troposphere. Additionally, tropospheric O3 is a key oxidant, and source of other oxidants (e.g, OH and NO3 radicals) for various volatile organic compounds (VOC). Recently, highl...
Ambient measurements of nitryl chloride (ClNO2) were performed at a rural site in Germany covering 3 periods in winter, summer, and autumn 2019 as part of the JULIAC campaign (Jülich Atmospheric Chemistry Project) that aimed for understanding the photochemical processes in air masses typical for mid-west Europe. Measurements were conducted at 50 m...
Surface ozone pollution in South Korea has increased over the past two decades, despite efforts to decrease emissions, and is pervasively in exceedance of the maximum daily 8-hr average (MDA8) standard of 60 ppb. Here, we investigate the 2015–2019 trends in surface ozone and NO2 concentrations over South Korea and the Seoul Metropolitan Area (SMA),...
Surface ozone pollution in South Korea has increased over
the past 2 decades, despite efforts to decrease emissions, and is
pervasively in exceedance of the maximum daily 8 h average (MDA8) standard
of 60 ppb. Here, we investigate the 2015–2019 trends in surface ozone and
NO2 concentrations over South Korea and the Seoul metropolitan area (SMA),
fo...
Citations
... This is because the change of NH 3 emissions alone will lead to a lower values of aerosol δ 15 N-NH 4 + in summer, as the non-fossil fuel related emissions (with lower δ 15 N-NH 3 , Table 1) are expected to be higher in summer than in winter due to higher temperatures, agricultural activities, and biomass burning (e.g. forest fires) (Gilliland et al., 2003;Gilliland et al., 2006;Hickman et al., 2021). On the other hand, the seasonal variation of precursors suggests that acid gas concentrations are lower in summer than in winter (such as in Fig. S3), and the higher temperatures and lower relative humidity in summer favor the gas-phase partitioning of NH 3 and HNO 3 , which will lead to lower f values in summer (Stelson and Seinfeld, 1982;Tang et al., 2021) and ultimately results in a stronger equilibrium fractionation effect in summer. ...
... As the soil emissions and biomass burning (e.g. forest fires) increase in summer and decrease in winter (Gilliland et al., 2003;Gilliland et al., 2006;Hickman et al., 2021), their contributions to atmospheric NH 4 + also exhibit a higher fraction in summer and a lower fraction in winter, which is exactly supported by our seasonal source partitioning result ( Fig. 4C and D) and the best correlation between NH 4 + and NO 3 − than other ions (Fig. 5). Therefore, the reduction of vehicle emissions due to the strict lockdown increases the importance of nonfossil fuel related emission sources in Changsha, which play a key role in determining the seasonal pattern of δ 15 N-NH 4 + during the lockdown. ...
... Satellite observations of NH 3 have now become widely available, allowing analysis of the entire global atmospheric distribution of NH 3 and its temporal variability (e.g. Hickman et al. (2021), Shephard et al. (2020), Van Damme et al. (2021), Wang et al. (2021)). Using model assimilation and inversion, satellite data is being used to estimate regional and global NH 3 emission and deposition budgets (e.g. ...
... The high concentrations in West Africa, which is one of the major global NH 3 hotspots (Van Damme et al., 2018), are likely the result of biomass burning emissions. Biomass burning emissions tend to drive seasonal variation in NH 3 vertical column densities (VCDs) in West Africa, with the largest emissions occurring late in the dry season and early rainy season (Hickman et al., 2021b). In addition to local emissions, biomass burning emissions and their reactive products are transported to the coast of West Africa during both the Northern Hemisphere rainy season, when they are transported from central and Southern Africa, and during the dry season, when they are transported from biomass burning regions to the east (Sauvage et al., 2007). ...
Atmospheric ammonia (NH3) is a precursor to fine particulate matter and a source of nitrogen (N) deposition that can adversely affect ecosystem health. The main sources of NH3 – agriculture and biomass burning – are undergoing are or expected to undergo substantial changes in Africa. Although evidence of increasing NH3 over parts of Africa has been observed, the mechanisms behind these trends are not well understood. Here we use observations of atmospheric NH3 vertical column densities (VCDs) from the Infrared Atmospheric Sounding Interferometer (IASI) along with other satellite observations of the land surface and atmosphere to evaluate how NH3 concentrations have changed over Africa from 2008 through 2018, and what has caused those changes. In West Africa NH3 VCDs are observed to increase during the late dry season, with increases of over 6 % yr−1 in Nigeria during February and March (p
In recent years, atmospheric ammonia (NH3) concentrations have increased in China. Ammonia control has become one of the next hot topics in air pollution mitigation with the increasing cost of acid gas emission reduction. In this study, using Infrared Atmospheric Sounding Interferometer (IASI) satellite observations, we analyzed the spatiotemporal distribution, the urban-rural gradient of the vertical column densities (VCDs) of NH3 and the contribution of influencing factors (meteorology, social, atmospheric acid gases, and NH3 emissions) in China from 2008 to 2019 using hotspot analysis, circular gradient analysis, geographical and temporal weighted regression, and some other methods. Our results showed that NH3 VCDs in China have significantly increased (31.88 %) from 2008 to 2019, with the highest occurring in North China Plain. The average NH3 VCDs in urban areas were significantly higher than those in rural areas, and the urban-rural gap in NH3 VCDs was widening. The results of circular gradient analysis showed an overall decreasing trend in NH3 VCDs along the urban-rural gradient. We used a geographically and temporally weighted regression model to analyze the contribution of various influencing factors to NH3 VCDs: meteorology (30.13 %), social (27.40 %), atmospheric acid gases (23.20 %), and NH3 emissions (19.28 %) factors. The results showed substantial spatiotemporal differences in the influencing factors. Atmospheric acid gas was the main reason for the increase in NH3 VCDs from 2008 to 2019. A more thorough understanding of the spatiotemporal distribution, urban-rural variations, and factors influencing NH3 in China will aid in developing control strategies to reduce PM2.5.
Ammonia (NH3) is an important atmospheric constituent. It plays a role in air quality and climate through the formation of ammonium sulfate and ammonium nitrate particles. It has also an impact on ecosystems through deposition processes. About 85 % of NH3 global anthropogenic emissions are related to food and feed production and, in particular, to the use of mineral fertilizers and manure management. Most global chemistry transport models (CTMs) rely on bottom-up emission inventories, which are subject to significant uncertainties. In this study, we estimate emissions from livestock by developing a new module to calculate ammonia emissions from the whole agricultural sector (from housing and storage to grazing and fertilizer application) within the ORCHIDEE (Organising Carbon and Hydrology In Dynamic Ecosystems) global land surface model. We detail the approach used for quantifying livestock feed management, manure application, and indoor and soil emissions and subsequently evaluate the model performance. Our results reflect China, India, Africa, Latin America, the USA, and Europe as the main contributors to global NH3 emissions, accounting for 80 % of the total budget. The global calculated emissions reach 44 Tg N yr−1 over the 2005–2015 period, which is within the range estimated by previous work. Key parameters (e.g., the pH of the manure, timing of N application, and atmospheric NH3 surface concentration) that drive the soil emissions have also been tested in order to assess the sensitivity of our model. Manure pH is the parameter to which modeled emissions are the most sensitive, with a 10 % change in emissions per percent change in pH. Even though we found an underestimation in our emissions over Europe (−26 %) and an overestimation in the USA (+56 %) compared with previous work, other hot spot regions are consistent. The calculated emission seasonality is in very good agreement with satellite-based emissions. These encouraging results prove the potential of coupling ORCHIDEE land-based emissions to CTMs, which are currently forced by bottom-up anthropogenic-centered inventories such as the CEDS (Community Emissions Data System).
Ammonia (NH3) is an important atmospheric constituent. It plays a role in air quality and climate through the formation of ammonium sulfate and ammonium nitrate particles. It has also an impact on ecosystems through deposition processes. About 85 % of NH3 global anthropogenic emissions are related to food and feed production and, in particular, to the use of mineral fertilizers and manure management. Most global chemistry transport models rely on bottom-up emission inventories subject to significant uncertainties. In this study, we estimate emissions from livestock by developing a new module to calculate ammonia emissions coming from the whole agricultural sector (from housing and storage to grazing and fertilizer applications) within the global land surface model ORCHIDEE. We detail the approach used for quantifying livestock feeding management, manure applications, and indoor and soil emissions and evaluate the model performance. Our results reflect China, India, Africa, Latin America, the USA, and Europe as the main contributors to the global NH3 emissions accounting for 80 % of the total budget. The global calculated emissions reach 44 Tg/yr over the 2005–2015 period, which is within the range estimated by previous work. Key parameters (pH of the manure, timing of the N application, atmospheric NH3 surface concentration, etc...) which drive the soil emissions have also been tested in order to assess the sensibility of our model. Manure pH is the parameter to which modeled emissions are the most sensitive with a 10 % change in emissions per % change in pH. Even though we found an under-estimation in our emissions over Europe (−26 %) and an over-estimation in the USA (+56 %) compared to previous work, other hot-spot regions are consistent. The calculated emissions seasonality is in very good agreement with satellite-based emissions. These encouraging results prove the potential of coupling ORCHIDEE land-based emissions to CTMs, which are currently forced by bottom-up anthropogenic-centered inventories such as CEDS.
