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Clouds as Sources and Sinks in the Life...

Student Spotlight: Zoe Pierrat

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Upcoming Seminar

Clouds as Sources and Sinks in the Life Cycle of the Pristine Aerosol

Wed, Dec 2, 2020

Zoom Seminar

Speaker: Meinrat O. Andreae

Institution(s): Max Planck Institute for Chemistry & Scripps Institution of Oceanography

Abstract:

We are conducting long-term measurements at two sites that experience extended periods of near-pristine conditions, one in Central Siberia (ZOTTO), the other in the Central Amazon Basin (ATTO). At both sites, we find the classical type of nucleation events (“bananas”) to be exceedingly rare, in contrast to sites that experience more significant anthropogenic influence. This calls in question the source of new particles in the regions represented by our remote sites.

Observations during the ACRIDICON-CHUVA aircraft campaign over the Amazon Basin showed high aerosol concentrations in the upper troposphere (UT), with number concentrations (normalized to standard conditions) often exceeding those in the boundary layer (BL) by one or two orders of magnitude.

Aerosol enhancements in the UT were consistently observed on all flights, using several aerosol metrics, including condensation nuclei (CN), cloud condensation nuclei (CCN), and chemical species mass concentrations. These UT aerosols were different in their composition and size distribution from the aerosol in the BL, making convective transport of particles unlikely as a source. The regions in the immediate outflow of deep convective clouds were depleted in aerosol particles, confirming the convective clouds as sinks of atmospheric aerosols. In contrast, dramatically enhanced small (<90 nm diameter) aerosol number concentrations were found in UT regions that had experienced outflow from deep convection in the preceding 24-48 hours. We also found elevated concentrations of larger (>90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN.

Our findings suggest that aerosol production takes place in the UT from volatile material brought up by deep convection, which is converted to condensable species in the UT. Subsequently, downward mixing and transport of upper tropospheric aerosol may be a source of particles to the BL, where they increase in size by the condensation of biogenic volatile organic carbon (BVOC) oxidation products. This may be an important source of aerosol particles in the remote and pristine troposphere, where aerosol nucleation and new particle formation is not commonly observed. We propose that this may have been the dominant process supplying secondary aerosols in the pristine atmosphere, making clouds the dominant control of both removal and production of atmospheric particles.

Zoom: https://ucla.zoom.us/j/98770296517 (must be signed-in to Zoom to join meeting)

Email congjoco@atmos.ucla.edu for password

Blanca Alvarez	Graduate Student	balvarez [at] atmos.ucla.edu
Tersi Arias	Graduate Student	tersiarias [at] atmos.ucla.edu
Alex Arnold	Graduate Student
Catherine Banach		cbanach [at] atmos.ucla.edu
Marco Sandoval Belmar	Graduate Student	marcsandovalb [at] atmos.ucla.edu
Nathaniel Brockway	Graduate Student	nwbrock [at] atmos.ucla.edu
Zhijiong Cao	Graduate Student	czj9763 [at] g.ucla.edu
Santiago Giraldo Cardenas	Graduate Student	santigiraldoc [at] atmos.ucla.edu
Daniel Clements	Graduate Student	dclements [at] atmos.ucla.edu
Jackson Darke	Graduate Student	jdarke40 [at] atmos.ucla.edu
Xiuyuan Ding	Graduate Student	dingxy [at] atmos.ucla.edu
Todd Emmenegger	Graduate Student	temmen [at] atmos.ucla.edu
Alyson Fritzmann		afritzmann [at] ucla.edu
Bowen Ge		gebowen [at] ucla.edu
Sara Graves		saragraves [at] ucla.edu
Paige Hoel	Graduate Student	paigehoel [at] atmos.ucla.edu
Calvin Howes	Graduate Student	calvinhowes [at] atmos.ucla.edu
Yue Huang	Graduate Student	yhuang [at] atmos.ucla.edu
Sarah Johnson	Graduate Student	sjohnson [at] atmos.ucla.edu
Ning Kang		nkang20 [at] atmos.ucla.edu
Yi-Hung Kuo	Graduate Student	yhkuo [at] atmos.ucla.edu
Danny Leung	Graduate Student	dannymleung [at] g.ucla.edu
Jiawen Li	Graduate Student	jiawen0110 [at] atmos.ucla.edu
Bessie Liu	Graduate Student	bessieliu [at] ucla.edu
Weiming Ma	Graduate Student	mawei [at] atmos.ucla.edu
Donglai Ma	Graduate Student	dma96 [at] atmos.ucla.edu
Gavin Madakumbura	Graduate Student	gavindayanga [at] atmos.ucla.edu
Daniel McCoy	Graduate Student	demccoy [at] atmos.ucla.edu
Matthew McKinney	Graduate Student	mmckinney [at] atmos.ucla.edu
Jordyn Moscoso	Graduate Student	jmoscoso [at] atmos.ucla.edu
Zoe Pierrat	Graduate Student	zpierra [at] atmos.ucla.edu
Mingxin Qu	Graduate Student	mingxin23 [at] atmos.ucla.edu
De'Marcus Robinson	Graduate Student	demarcu1.robinson [at] atmos.ucla.edu
Rodrigo Rodakoviski	Graduate Student	rodakoviski [at] atmos.ucla.edu
Jiaqi Shen	Graduate Student	jqshen [at] ucla.edu
Zhan Shi		zhanshi1997 [at] gmail.com
Clara Si	Graduate Student	csi [at] atmos.cula.edu
Dominique Stumbaugh		NSTUMBAUGH07 [at] GMAIL.COM
Katie Tuite	Graduate Student	ktuite [at] atmos.ucla.edu
Francis Turney	Graduate Student	fturney [at] ucla.edu
Sarah Worden	Graduate Student
Kyongwon (Kevin) Yoo	Graduate Student	kyongwonyoo93 [at] atmos.ucla.edu
Ken Zhao	Graduate Student	kzhao [at] atmos.ucla.edu
Zewen Zheng	Graduate Student	zewenzheng [at] atmos.ucla.edu
Kuilin Zhu		kuilin [at] g.ucla.edu

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