\documentclass[10pt]{article}

\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage[section]{placeins}
\usepackage{xcolor}
\usepackage{breakcites}
\usepackage{lineno}
\usepackage{hyphenat}





\PassOptionsToPackage{hyphens}{url}
\usepackage[colorlinks = true,
            linkcolor = blue,
            urlcolor  = blue,
            citecolor = blue,
            anchorcolor = blue]{hyperref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
  \errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother


\usepackage{natbib}




\renewenvironment{abstract}
  {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize}
  {\bigskip}

\titlespacing{\section}{0pt}{*3}{*1}
\titlespacing{\subsection}{0pt}{*2}{*0.5}
\titlespacing{\subsubsection}{0pt}{*1.5}{0pt}


\usepackage{authblk}


\usepackage{graphicx}
\usepackage[space]{grffile}
\usepackage{latexsym}
\usepackage{textcomp}
\usepackage{longtable}
\usepackage{tabulary}
\usepackage{booktabs,array,multirow}
\usepackage{amsfonts,amsmath,amssymb}
\providecommand\citet{\cite}
\providecommand\citep{\cite}
\providecommand\citealt{\cite}
% You can conditionalize code for latexml or normal latex using this.
\newif\iflatexml\latexmlfalse
\providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}%

\AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}}

\usepackage[utf8]{inputenc}
\usepackage[ngerman,english]{babel}



\usepackage{float}








\begin{document}

\title{Modulation of mid-Holocene northern African rainfall by direct and
indirect dust aerosol effects}



\author[1]{Alexander Thompson}%
\author[1]{Christopher Skinner}%
\author[2]{Christopher Poulsen}%
\author[1]{Jiang Zhu}%
\affil[1]{University of Michigan Ann Arbor}%
\affil[2]{University of Michigan}%


\vspace{-1em}



  
  \date{May 08, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
During the mid-Holocene (MH, 6,000 years BP), precessional forcing drove
enhanced monsoon rainfall, expanded vegetation cover, and reduced dust
emissions throughout the African Sahara. The orbital forcing and
feedback of vegetation albedo have been widely studied with climate
models, but are found to be insufficient to explain the magnitude and
location of rainfall anomalies suggested from proxy reconstructions. The
feedback of reduced Saharan dust loading has been less-studied because
Paleoclimate Modelling Intercomparison Project (PMIP) Phase 2/3 models
did not incorporate the decreased MH Saharan dust emissions. Several
recent modeling studies investigated the MH Saharan hydroclimate
response to reduced dust loading; however, their models only resolved
the direct effect from dust aerosols (i.e. direct radiative forcing),
which leaves the contribution from indirect dust aerosol effects (i.e.
dust aerosol-cloud interactions) largely unknown. Here we investigate
the hydroclimate response due to Saharan dust using CESM CAM5-chem,
which includes both the direct and indirect dust aerosol effects. In the
simulations, reduced Saharan dust directly increases monsoon season
(JJAS) net shortwave radiative flux at the surface, which drives
continental warming. Convective clouds and convective precipitation are
subsequently enhanced and, due to the overwhelming convective nature of
this monsoonal region, total Saharan (20--31\selectlanguage{ngerman}°N, 20°W--30°E)
precipitation increases by 11.9\%. However, indirect dust aerosol
effects counteract the increase from convection precipitation. A
reduction in Saharan dust decreases cloud nuclei number concentration
and increases cloud droplet size, which in turn reduces stratus cloud
cover and large-scale stable rainfall. Overall, the decrease in
large-scale stable rainfall due to indirect dust effects reduces total
precipitation by 12.5\%. The total rainfall increase of 0.27 mm/day from
reduced dust is significant but smaller than the response to changes in
vegetation cover (1.19 mm/day). While these results indicate that less
Saharan dust during the MH likely enhanced Saharan rainfall, they also
suggest that a reduction in the indirect effects of dust likely dampened
the overall response of rainfall to the MH dust forcing.%
\end{abstract}\selectlanguage{ngerman}%



\sloppy




\selectlanguage{english}
\FloatBarrier
\end{document}

