June 1, 2016 - October 31, 2017 Paquita Zuidema, U of M

SST

1019

28

20

1021

Ascension DOE AMF1 deploymentLayered Atlantic Smoke Interactions Campaign (LASIC)

June 1, 2016 - October 31, 2017

Paquita Zuidema, U of Miami and many others

SST

1019

28

20

1023

1021

AscensionDOE AMF1 deployment

Layered Atlantic Smoke Interactions Campaign (LASIC)June 1, 2016 - October 31, 2017

AscensionSt. Helena

grey contours- cloud fraction [50-100]%, coloured contour lines - sea surface temperature

2000-2012 IGRA radiosonde monthly-mean profiles

Ascension Island is located in the trade-wind cumulus regime

no good theory yet on what establishes low cloud amount

2002-2011 MODIS climatology: yellow-red AOD; blue-purple contours are cloud fraction; firecounts over land; ERA-I 600 hap winds

Adebiyi et al. 2015

extensive shortwave-absorbing aerosol (smoke) layer over theremote Atlantic from July through October

smoke can either increase (brighten) or decrease (darken) the TOA reflectance, depending

on the underlying surface

varies strongly withaerosol single-scattering-albedo

Remer, 2009

Adebiyi et al., 2015, JCLIM

CERES albedo

MODIS low cloud fraction (yellow-red)

ERA-I

green

pristine polluted10-yr Aug-Sept

composite means

the southeast Atlantic is brighter, when smoke is present overhead: clouds are thicker (Wilcox, 2010) and more of them within a more

stable environment (Loeb&Schuster, 2008)

shortwave-absorbing aerosols above low cloudssupport the cloud deck if the aerosols increase

cloud-top-inversion-level stability (e.g., Johnson, 2004)

main aerosol-cloud interaction is semi-direct effect

LASIC hypotheses & projects

LASIC scientific goals are articulated through the following hypotheses:Hypothesis 1 (H1): The single-scattering albedo of the carbonaceous aerosol overlying Ascension increases during the BB season as has been documented over land.Hypothesis 2 (H2): Low cloud properties at Ascension vary as a function of the amount, vertical distribution, and optical properties of absorbing aerosol aloft that is distinct from meteorology.Hypothesis 3 (H3): Carbonaceous aerosol are present within the Ascension Island boundary layer, where they are capable of affecting cloud microphysics, precipitation susceptibility, and the cloud mesoscale organization.Hypothesis 4 (H4): The evolution of the cloudy boundary layer between St. Helena and Ascension Island varies as a function of the absorbing aerosol loadings aloft as well as large-scale environmental parameters such as sea surface temperature.LASIC science goals and objectives will be achieved by:1.Characterizing the microphysical and optical properties of the carbonaceous aerosol at

Ascension Island as a function of time.2.Characterizing the low cloud properties at Ascension Island as a function of the vertical

location and optical properties of the absorbing aerosol within the atmospheric column, controlled for thermodynamic state and prior cloud evolution.

3.When carbonaceous aerosol is present within the boundary layer, assessing the aerosol size distribution and hygroscopicity, and relating the aerosol properties to the cloud spatial distribution, its microphysics, precipitation susceptibility, and cloud mesoscale organization.

4.Assessing the evolution of the cloudy boundary layer from St. Helena to Ascension Island under a wide range of atmospheric aerosol conditions as well as large-scale environmental conditions.

from left to right: vertical profiles of PCASP accumulation-mode aerosol concentration and the nephelometer scattering coefficient at 0.55 micron indicate aerosol concentrations exceeding 500 cm-3 in the boundary layer, with the potential temperature and water vapor mixing ratio profiles indicating two well-mixed layers. The grey line indicates cloud base height. courtesy of Steve Abel, UK Met Office.

altit

ude

(m)

Ascension Island profile data from SAFARI-UK September 2, 2000 research flight

5

potential temperature

030W

20S

300 320 K

600

700

800

900

1000

400

500

600

700

800

900

400

500

1000

mixing ratio

pres

sure

2 6 10 g/kg

St. Helena

pres

sure

September-October 1000 hPa geopotential height

1.7

1.3

0.9

km

30W 20W 0 10E

10N

0

10S

20S

30S

8

Ascension

St. Helena

Ascension

Sept-Oct 2013 HYSPLIT trajectoires andERA-I surface winds

September-mean profiles from 2000-2012 IGRA radiosondes

https://www.arm.gov/campaigns/amf2016lasic

aerosol instrumentation

chemistry instrumentation

AMF1

3-channel microwave radiometer (MWR3C)* integrated liquid water and water vapor

balloon-borne sounding system (SONDE)*4x/daily increasing to 8x/daily for 2 months

temperature, humidity and wind vertical structure

ceilometer (VCEIL)* cloud base

radar wind profiler (RWP)* wind vertical structure

W-band scanning cloud radar (WSACR)* cloud and precipitation spatial structure

W-band zenith cloud radar (WACR)* cloud and precipitation vertical structure

K-band scanning cloud radar (KASACR)* cloud and precipitation spatial structure

micropulse lidar (MPL)* aerosol vertical structure

atmospheric emitted radiance interferometer (AERI)* cloud liquid water path and effective radii

multifilter rotating shadowband radiometer (MFRSR)* aerosol optical depth

Narrow Field of View (NFOV)* cloud optical depth and effective radius

solar array spectrometer (SASHE & SASZE)* radiative closure

surface energy balance system (SEBS)* surface energy balance. soil moisture and flux measurements are not needed.

surface radiation measurements (SKYRAD, MFR, GNDRAD)* surface radiation balance (overlap with SEBS?)

meteorological instrumentation (MET)* surface air layer properties

optical rain gauge (ORG)* surface rain

tower camera (TWRCAM)* photo imagery

total-sky camera (TSI)* cloud fraction

AMF1 cloud instrumentation

AMF1





















scanning radar boundary-layer RHIstowards documenting cloud vertical structure well

365 m

AMF1





















email list [email protected] contact Jackie Marshall

and/or myselffor inclusion

[email protected]

• opportunities for guest instrumentation• DOE ARM datasets all publicly-available

mailto:[email protected]

mailto:[email protected]?subject=

extra slides

monthly-mean profiles from 2000-2012 IGRA radiosondes

classical double-lobed trade-wind cumulus vertical thermodynamic structuredeepest boundary layer in July, shallowest in November

575 m365 m

improved assessment of diurnal cycle with AMF1 4x/8x daily soundingstowards assessing semi-direct effect on diurnal cycle,

cloudy BL evolution between St. Helena and Ascension

grey contours- cloud fraction [50-100]%, coloured contour lines - sea surface temperaturemonthly-mean profiles from 2000-2012 IGRA radiosondes

UK Met Office* monthly-mean surface wind roses, 2005-2014* *Simon Fox, Ascension Island UK Met Office

MarchFebruaryJanuary April

May AugustJulyJune

September DecemberNovemberOctober

winds consistent, SSE December-March, ESE April-October

Eck et al., 2013

AERONET observations over land suggest BB aerosols become less absorptive from July-November (because of fuel type)

June 1, 2016 - October 31, 2017 Paquita Zuidema, U of M

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