English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We investigate the sensitivity of aerosol representationin the regional climate model RegCM4 for two dust parameterizations for theperiod 2007–2014 over the Sahara and the Mediterranean. We apply twodiscretization methods of the dust size distribution keeping the total massconstant: (1) the default RegCM4 4-bin approach, where the size range of eachbin is calculated using an equal, logarithmic separation of the total sizerange of dust, using the diameter of dust particles, and (2) a newlyimplemented 12-bin approach with each bin defined according to anisogradient method where the size ranges are dependent on the dry depositionvelocity of dust particles. Increasing the number of transported dust sizebins theoretically improves the representation of the physical properties ofdust particles within the same size bin. Thus, more size bins improve thesimulation of atmospheric processes. The radiative effects of dust over thearea are discussed and evaluated with the CALIPSO dust optical depth (DOD).This study is among the first studies evaluating the vertical profile ofsimulated dust with a pure dust product. Reanalysis winds from ERA-Interimand the total precipitation flux from the Climate Research Unit (CRU) observational gridded databaseare used to evaluate and explain the discrepancies between model andobservations. The new dust binning approach increases the dust column burdenby 4 and 3 % for fine and coarse particles, respectively, whichincreases DOD by 10 % over the desert and the Mediterranean. Consequently,negative shortwave radiative forcing (RF) is enhanced by more than 10 % at the top of theatmosphere and by 1 to 5 % on the surface. Positive longwave RFlocally increases by more than 0.1 W m<sup>−2</sup> in a large portion ofthe Sahara, the northern part of the Arabian Peninsula and the MiddleEast. The four-bin isolog method is to some extent numerically efficient,nevertheless our work highlights that the simplified representation of thefour-bin approach produces less dust optical depth and RF, a fact that should be taken into account by future studies of the same region

Impact of dust size parameterizations on aerosol burden and radiative forcing in RegCM4