On the impact of aerosols on soil erosion

Nissan, Hannah; Toumi, Ralf

doi:10.1002/2013gl058289

Cited by 5 publications

(3 citation statements)

References 30 publications

(53 reference statements)

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“…We do not find an amplified sensitivity of total JJAS soil erosion to aerosols compared with the precipitation response, as was suggested by earlier idealised simulations of convective and orographic rainfall (Nissan and Toumi, ). At the hourly level, the definition of rainfall erosivity as the product of two positively correlated variables, rainfall kinetic energy flux and surface runoff rate (Eq.…”

Section: Resultssupporting

confidence: 85%

“…As attempts are made to curb emissions of aerosol pollutants, policy makers should be informed about how these changes could affect a range of outcomes, including precipitation amount but also ecosystem services, agriculture and health. It might be anticipated that any change in erosion would mirror shifts in rainfall, but an idealised model study found that an increase in aerosol concentrations resulted in a change in rainfall erosivity which was amplified relative to the change in precipitation (Nissan and Toumi, ). Thus there is evidence to suggest that the agricultural impact of future measures to reduce emissions could be larger than anticipated.…”

Section: Introductionmentioning

confidence: 99%

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Regional modelling of rainfall erosivity: sensitivity of soil erosion to aerosol emissions

Nissan

Toumi

2016

Quart J Royal Meteoro Soc

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A rainfall erosivity scheme is implemented into the widely used regional atmosphere-land model, WRF. Rainfall erosivity is parametrized from hourly precipitation and surface runoff in a high resolution (4 km) convection-permitting model. The scheme is used to examine the potential effects of changes in atmospheric aerosol concentrations on soil erosion in a case-study of northern India and the surrounding countries for the 2010 monsoon season, using a model which isolates the indirect effect on cloud microphysics only. This study offers a preliminary investigation into this emerging topic, but longer simulations would be needed to establish a robust signal.Summer precipitation is reduced in most areas and the monsoon circulation weakens for increases in cloud condensation nuclei concentrations. This can be attributed to localised cloud microphysical changes in the northeast of India, which induce a dynamic response opposing the monsoon circulation. The two regions of greatest decrease in erosion with increasing aerosol are in the Western Ghats and the Ganges Delta, both significant cropland areas. However, the effect is not uniform, with isolated local increases in soil erosion. These results suggest that, while efforts to reduce anthropogenic aerosol emissions may improve water availability for crops through enhanced rainfall, these benefits are likely to be tempered by an increase in soil erosion, though robust local changes were difficult to predict.

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Section: Resultssupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Regional modelling of rainfall erosivity: sensitivity of soil erosion to aerosol emissions

Nissan

Toumi

2016

Quart J Royal Meteoro Soc

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“…In M12, suppression of precipitation with increasing aerosol loading was seen. In another WRF study with configurations of the simulations nearly identical to that of M12 except for the wind profile, Nissan and Toumi (2013) showed an increase in precipitation when aerosol loading increases. Van den Heever and Cotton (2007) showed a strong dependence of aerosol-cloud interaction on the background aerosol concentration.…”

Section: Introductionmentioning

confidence: 91%

Sensitivity study of the aerosol effects on a supercell storm throughout its lifetime

Takeishi

Storelvmo

2014

Preprint

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<p><strong>Abstract.</strong> An increase in atmospheric aerosol loading could alter the microphysics, dynamics, and radiative characteristics of deep convective clouds. Earlier modeling studies have shown that the effects of increased aerosols on the amount of precipitation from deep convective clouds are model-dependent. This study aims to understand the effects of increased aerosol loading on a deep convective cloud throughout its lifetime with the use of the Weather Research and Forecasting (WRF) model as a cloud-resolving model (CRM). It simulates an idealized supercell thunderstorm with 8 different aerosol loadings, for three different cloud microphysics schemes. Variation in aerosol concentration is mimicked by varying either cloud droplet number concentration or the number of activated cloud condensation nuclei. We show that the sensitivity to aerosol loading is dependent on the choice of microphysics scheme. For the schemes that are sensitive to aerosols loading, the production of graupel via riming of snow is the key factor determining the precipitation response. The formulation of snow riming depends on the microphysics scheme and is usually a function of two competing effects, the size effect and the number effect. In many simulations, a decrease in riming is seen with increased aerosol loading, due to the decreased droplet size that lowers the riming efficiency drastically. This decrease in droplet size also results in a delay in the onset of precipitation, as well as so-called warm rain suppression. Although these characteristics of convective invigoration (Rosenfeld et al., 2008) are seen in the first few hours of the simulations, variation in the accumulated precipitation mainly stems from graupel production rather than convective invigoration. These results emphasize the importance of accurate representations of graupel formation in microphysics schemes.</p>

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