Modelling the air-surface exchange of ammonia from the field to global scale

The Working Group addressed the current understanding and uncertainties in the processes controlling ammonia (NH3) bi-directional exchange, and in the application of numerical models to describe these processes. As a starting point for the discussion, the Working Group drew on the background document prepared by Flechard et al. (2013)...

Nitrogen: Too much of a vital resource

Nitrogen (N) is a key nutrient, vital for the survival of humans and all other living organisms. While di-nitrogen gas (N2) is abundant in the atmosphere, most organisms are unable to use this chemically unreactive form. First it must be converted or fixed߿ݠinto a reactive form such as ammonia (NH3) or nitrogen oxide (NOx). These and other forms...

Our Nutrient World - The challenge to produce more food and energy with less pollution

Executive Summary Key Points Nutrient Benefits and Threats * The sustainability of our world depends fundamentally on nutrients. In order to feed 7 billion people, humans have more than doubled global land-based cycling of nitrogen (N) and phosphorus (P). * The world’s N and P cycles are now out of balance, causing major environmental, health...

Towards a climate-dependent paradigm of ammonia emission and deposition

Existing descriptions of bi-directional ammonia (NH3) land-atmosphere exchange incorporate temperature and moisture controls, and are beginning to be used in regional chemical transport models. However, such models have typically applied simpler emission factors to upscale the main NH3 emission terms. While this approach has successfully...

The global nutrient challenge: From science to public engagement

Among the many environment and development challenges facing humanity, it is fair to say that nutrients do not currently feature so regularly in the newspapers, radio and television. The media tends to prefer easy single issues which affect our daily lives in a clear-cut way. The role of carbon in climate change is a good example. We all depend...

The shape of nitrogen to come

An analysis reveals the huge impact of human activity on the nitrogen cycle in China. With global use of Earth’s resources rising per head, the findings call for a re-evaluation of the consumption patterns of developed societies.

Towards a climate-dependent paradigm of ammonia emission and deposition

Existing descriptions of bi-directional ammonia (NH3) land–atmosphere exchange incorporate temperature and moisture controls, and are beginning to be used in regional chemical transport models. However, such models have typically applied simpler emission factors to upscale the main NH3 emission terms. While this approach has successfully...

Assessment of Nitrogen Fluxes to Air and Water from Site Scale to Continental Scale

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Regional atmospheric budgets of reduced nitrogen over the British isles assessed using a multi-layer atmospheric transport model

Atmospheric budgets of reduced nitrogen for the major political regions of the British Isles are investigated with a multi-layer atmospheric transport model. The model is validated against measurements of NH3 concentration and is developed to provide atmospheric budgets for defined subdomains of the British Isles. The study shows that NH3...

Measurements and parameterizations of small aerosol deposition velocities to grassland, arable crops, and forest: Influence of surface roughness length on deposition

New micrometeorological measurements of small (0.1-0.2 u diameter) aerosol particle fluxes using the eddy correlation technique are presented for moorland and also for grassland vegetation, the latter measurements being made both before and after cutting of the grassland to observe the resultant change in particle deposition velocity. These data...