Assessment of the Met Office dust forecast model using observations from the GERBILS campaign

Johnson, Ben; Brooks, M. E.; Walters, David; Woodward, Stephanie; Christopher, S. A.; Schepanski, Kerstin

doi:10.1002/qj.736

Cited by 36 publications

(22 citation statements)

References 62 publications

(84 reference statements)

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“…Indeed, the very different model responses to the different dust representations shown in Fig. 21 highlight that despite numerous advances made in characterising the physical and optical properties of mineral dust aerosol in a number of aircraft and ground-based measurement campaigns (Haywood et al, , 2003aJohnson et al, 2011) large uncertainties still remain. Further constraining these uncertainties is key for an accurate representation of the dust radiative impacts in both NWP and climate models.…”

Section: Discussionmentioning

confidence: 99%

Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model

et al. 2014

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Abstract. The inclusion of the direct and indirect radiative effects of aerosols in high-resolution global numerical weather prediction (NWP) models is being increasingly recognised as important for the improved accuracy of shortrange weather forecasts. In this study the impacts of increasing the aerosol complexity in the global NWP configuration of the Met Office Unified Model (MetUM) are investigated. A hierarchy of aerosol representations are evaluated including three-dimensional monthly mean speciated aerosol climatologies, fully prognostic aerosols modelled using the CLASSIC aerosol scheme and finally, initialised aerosols using assimilated aerosol fields from the GEMS project. The prognostic aerosol schemes are better able to predict the temporal and spatial variation of atmospheric aerosol optical depth, which is particularly important in cases of large sporadic aerosol events such as large dust storms or forest fires. Including the direct effect of aerosols improves model biases in outgoing long-wave radiation over West Africa due to a better representation of dust. However, uncertainties in dust optical properties propagate to its direct effect and the subsequent model response. Inclusion of the indirect aerosol effects improves surface radiation biases at the North Slope of Alaska ARM site due to lower cloud amounts in highlatitude clean-air regions. This leads to improved temperature and height forecasts in this region. Impacts on the global mean model precipitation and large-scale circulation fields were found to be generally small in the short-range forecasts. However, the indirect aerosol effect leads to a strengthening of the low-level monsoon flow over the Arabian Sea and Bay of Bengal and an increase in precipitation over Southeast Asia. Regional impacts on the African Easterly Jet (AEJ) are also presented with the large dust loading in the aerosol climatology enhancing of the heat low over West Africa and weakening the AEJ. This study highlights the importance of including a more realistic treatment of aerosol-cloud interactions in global NWP models and the potential for improved global environmental prediction systems through the incorporation of more complex aerosol schemes.

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Section: Discussionmentioning

confidence: 99%

Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model

et al. 2014

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“…A full description is included in Woodage et al (2010); some tuning of the dust emission parameters was required to produce realistic dust loadings in HiGAM. Note that the scheme is not the same as the HadGEM2 scheme described in Johnson et al (2011), although they are both stages along the development path from the original Woodward (2001) formulation. Dust is fully interactive with representation of direct dust radiative effects and feedbacks.…”

Section: Higem Modelmentioning

confidence: 99%

Examination of long‐wave radiative bias in general circulation models over North Africa during May–July

Allan

Woodage

Milton

et al. 2010

Quart J Royal Meteoro Soc

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“…Extensive studies over the Sahara region also highlight the relevance in use of high-resolution numerical models for simulation of such events (e.g. Knippertz et al, 2009;Marsham et al, 2011;Johnson et al, 2011;Solomos et al, 2012;Tegen et al, 2013;Schepanski et al 2013). …”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of "an American haboob"

et al. 2014

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Abstract.A dust storm of fearful proportions hit Phoenix in the early evening hours of 5 July 2011. This storm, an American haboob, was predicted hours in advance because numerical, land-atmosphere modeling, computing power and remote sensing of dust events have improved greatly over the past decade. High-resolution numerical models are required for accurate simulation of the small scales of the haboob process, with high velocity surface winds produced by strong convection and severe downbursts. Dust productive areas in this region consist mainly of agricultural fields, with soil surfaces disturbed by plowing and tracks of land in the high Sonoran Desert laid barren by ongoing draught.Model simulation of the 5 July 2011 dust storm uses the coupled atmospheric-dust model NMME-DREAM (Nonhydrostatic Mesoscale Model on E grid, Janjic et al., 2001; Dust REgional Atmospheric Model, Nickovic et al., 2001;Pérez et al., 2006) with 4 km horizontal resolution. A mask of the potentially dust productive regions is obtained from the land cover and the normalized difference vegetation index (NDVI) data from the Moderate Resolution Imaging Spectroradiometer (MODIS). The scope of this paper is validation of the dust model performance, and not use of the model as a tool to investigate mechanisms related to the storm. Results demonstrate the potential technical capacity and availability of the relevant data to build an operational system for dust storm forecasting as a part of a warning system. Model results are compared with radar and other satellitebased images and surface meteorological and PM 10 observations. The atmospheric model successfully hindcasted the position of the front in space and time, with about 1 h late arrival in Phoenix. The dust model predicted the rapid uptake of dust and high values of dust concentration in the ensuing storm. South of Phoenix, over the closest source regions (∼25 km), the model PM 10 surface dust concentration reached ∼2500 µg m −3 , but underestimated the values measured by the PM 10 stations within the city. Model results are also validated by the MODIS aerosol optical depth (AOD), employing deep blue (DB) algorithms for aerosol loadings. Model validation included Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), equipped with the lidar instrument, to disclose the vertical structure of dust aerosols as well as aerosol subtypes. Promising results encourage further research and application of high-resolution modeling and satellite-based remote sensing to warn of approaching severe dust events and reduce risks for safety and health.

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Assessment of the Met Office dust forecast model using observations from the GERBILS campaign

Cited by 36 publications

References 62 publications

Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model

Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model

Examination of long‐wave radiative bias in general circulation models over North Africa during May–July

Numerical simulation of "an American haboob"

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Assessment of the Met Office dust forecast model using observations from the GERBILS campaign

Cited by 36 publications

References 62 publications

Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model

Impacts of increasing the aerosol complexity in the Met Office global numerical weather prediction model

Examination of long‐wave radiative bias in general circulation models over North Africa during May–July

Numerical simulation of &quot;an American haboob&quot;

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Numerical simulation of "an American haboob"