Influence of dry‐season vegetation variability on Sahelian dust during 2002–2015

Kergoat, Laurent; Guichard, Françoise; Pierre, Caroline; Vassal, C.

doi:10.1002/2016gl072317

Cited by 20 publications

(18 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The main impact of rainfall on wind erosion operates through dry vegetation during the late dry season and beginning of the next rainy season (i.e., dry stalks and litter from the previous vegetation cycle, while the new green vegetation mass is still very low) because most wind erosion occurs during this period of the year when total vegetation amounts are low and large wind speeds are frequent. Thus, wind erosion depends on the previous vegetation maximum, which depends on the rainfall amount and distribution during the previous rainy season (e.g., Kergoat et al, 2017). Annual horizontal fluxes are anticorrelated (although correlation coefficients are often not significant at the 0·10 level) with the vegetation maximum mass of the previous year for most scenarios (R = À0·39 to À0·94, except for LongC Mil).…”

Section: Interannual Variability Of Wind Erosionmentioning

confidence: 99%

Impact of Agropastoral Management on Wind Erosion in Sahelian Croplands

Pierre

Kergoat

Hiernaux³

et al. 2017

Land Degrad Dev

Self Cite

View full text Add to dashboard Cite

In the Sahel, climate change and demographic growth are raising major concerns about the ability of crop yields to support the local population. Agropastoral management affects wind erosion (e.g., through crop residue management and tillage practices, which modify surface characteristics), which itself substantially affects soil fertility and thus crop yields. There is therefore a need to assess the potential impact of the main Sahelian cropping practices – like sowing, manuring, and crop residue management – on wind erosion. Using a modeling approach adapted to an experimental site located in southwestern Niger over the period 2006–2012, and scenarios that describe a set of agropastoral practices, the impacts of these practices on wind erosion are simulated and compared. The results indicate that horizontal fluxes differ by a factor of 10 among scenarios, with annual horizontal fluxes ranging from 121 to 1,317 kg m−1. Modeled wind erosion is most sensitive to the mass of crop residues in the late dry season, but different practices dealing with crop growth or with crop residue management may result in fluxes of the similar magnitude. The collection of the crop residues after grain harvest increases wind erosion, whereas grazing might have mixed effects, probably further mediated by the mobility of livestock as a response to forage availability. The seasonal dynamics of the monthly cumulated horizontal fluxes vary depending on practice; however, the annual cumulated horizontal fluxes are closely correlated with meteorological conditions such as wind speed and rainfall in the previous year. Copyright © 2017 John Wiley & Sons, Ltd.

show abstract

Section: Interannual Variability Of Wind Erosionmentioning

confidence: 99%

Impact of Agropastoral Management on Wind Erosion in Sahelian Croplands

Pierre

Kergoat

Hiernaux³

et al. 2017

Land Degrad Dev

Self Cite

View full text Add to dashboard Cite

show abstract

“…At that time agricultural soils are bare, and thus, it is the time of the year during which they are the most erodible (Abdourhamane Touré et al, ; Pierre et al, ). In the same way, during this period, due to pasture and/or natural decomposition, rangelands exhibit a minimum residue of the vegetation of the previous year and thus are also potentially more erodible than at any other time of the year (Kergoat et al, ; Pierre et al, ). This suggests that at least in this part of the Sahel, there is a near perfect conjunction between the period of the year during which the soil surface is the most erodible and the period during which the frequency of strong winds is maximum.…”

Section: Resultsmentioning

confidence: 99%

Dust Uplift Potential in the Central Sahel: An Analysis Based on 10 years of Meteorological Measurements at High Temporal Resolution

et al. 2017

View full text Add to dashboard Cite

A 10 year data set of wind speed and precipitation recorded in two Sahelian stations located in Niger and Mali is used to investigate the duration and the diurnal and seasonal cycles of high wind speeds and Dust Uplift Potential (DUP). The results indicate that high wind speeds, those greater than the threshold wind velocity required to initiate wind erosion (TWV) over a bare soil occurred in the middle and late morning during the dry and wet seasons but also at nighttime during the wet season. However, the morning wind speeds are only slightly greater than TWV leading to low DUP. On the opposite, the high wind velocities associated to the nocturnal mesoscale convective systems crossing the Sahel during the wet season are responsible for the highest potential wind erosion events. This leads to a strong seasonality of DUP with more than 70% occurring in less than 90 days, from mid‐April to mid‐July. The duration of the high wind speed events is very short since more than 80% last for less than 3 h, suggesting that the frequency of the observations performed in SYNOP meteorological stations is not sufficient to correctly quantify the contribution of such events to DUP. Finally, by combining precipitation and DUP, we estimated that precipitation should have a relatively limited role in terms of inhibition of wind erosion in this region with precipitation only affecting 25% of total DUP.

show abstract

“…In addition to that, dust emissions is further complicated by suppressing influences of soil moisture (Fécan et al, 1998) and vegetation cover, including brown vegetation from a previous rainy period (Kergoat et al, 2017), which can vary on relatively small time and spatial scales. This is particularly acute in the semiarid Sahel with its seasonal vegetation, also creating large variations in surface roughness (Cowie et al, 2013).…”

Section: User Requirements For Desert Mineral Dust Emissionsmentioning

confidence: 99%

“…Finally, the dust-focused satellite data should be complemented by improved spaceborne assessments of soil moisture, vegetation cover (green and brown), and soil mineralogy to better characterize varying conditions in source regions (Kergoat et al, 2017). For soil mineralogy, airborne and spaceborne spectroscopic mapping (such as DLR En-MAP and upcoming NASA-EMIT missions) provides a new resource to determine the relative abundance of the key dust source minerals with sufficient detail and coverage, but this resource has been virtually unexplored in the context of dust modeling.…”

Section: User Requirements For Desert Mineral Dust Emissionsmentioning

confidence: 99%

Status and future of numerical atmospheric aerosol prediction with a focus on data requirements

et al. 2018

View full text Add to dashboard Cite

Abstract. Numerical prediction of aerosol particle properties has become an important activity at many research and operational weather centers. This development is due to growing interest from a diverse set of stakeholders, such as air quality regulatory bodies, aviation and military authorities, solar energy plant managers, climate services providers, and health professionals. Owing to the complexity of atmospheric aerosol processes and their sensitivity to the underlying meteorological conditions, the prediction of aerosol particle concentrations and properties in the numerical weather prediction (NWP) framework faces a number of challenges. The modeling of numerous aerosol-related parameters increases computational expense. Errors in aerosol prediction concern all processes involved in the aerosol life cycle including (a) errors on the source terms (for both anthropogenic and natural emissions), (b) errors directly dependent on the meteorology (e.g., mixing, transport, scavenging by precipitation), and (c) errors related to aerosol chemistry (e.g., nucleation, gas-aerosol partitioning, chemical transformation and growth, hygroscopicity). Finally, there are fundamental uncertainties and significant processing overhead in the diverse observations used for verification and assimilation within these systems. Indeed, a significant component of aerosol forecast development consists in streamlining aerosol-related observations and reducing the most important errors through model development and data assimilation. Aerosol particle observations from satellite-and groundbased platforms have been crucial to guide model development of the recent years and have been made more readily available for model evaluation and assimilation. However, for the sustainability of the aerosol particle prediction activities around the globe, it is crucial that quality aerosol observations continue to be made available from different platforms (space, near surface, and aircraft) and freely shared. This paper reviews current requirements for aerosol observations in the context of the operational activities carried out at various global and regional centers. While some of the requirements are equally applicable to aerosol-climate, the focus here is on global operational prediction of aerosol properties such as mass concentrations and optical parameters. It is also recognized that the term "requirements" is loosely used here given the diversity in global aerosol observing systems and that utilized data are typically not from operational sources. Most operational models are based on bulk schemes that do not predict the size distribution of the aerosol particles. Others are based on a mix of "bin" and bulk schemes with limited capability of simulating the size information. However the next generation of aerosol operational models will output both mass and number density concentration to provide a more complete description of the aerosol population. A brief overview of the state of the art is provided with an introduction on the importance of ...

show abstract

Influence of dry‐season vegetation variability on Sahelian dust during 2002–2015

Cited by 20 publications

References 45 publications

Impact of Agropastoral Management on Wind Erosion in Sahelian Croplands

Impact of Agropastoral Management on Wind Erosion in Sahelian Croplands

Dust Uplift Potential in the Central Sahel: An Analysis Based on 10 years of Meteorological Measurements at High Temporal Resolution

Status and future of numerical atmospheric aerosol prediction with a focus on data requirements

Contact Info

Product

Resources

About