hygroscopicity parameter from lasic observations and ......and ruby leung (pnnl) • wrf-hemc with...
TRANSCRIPT
![Page 1: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/1.jpg)
Hygroscopicity parameter from LASIC observations and comparison to models
Pablo SaideDepartment of Atmospheric & Oceanic Sciences (AOS) and
Institute of the Environment and Sustainability (IoES)University of California, Los Angeles (UCLA)
With substantial contributions from Calvin Howes, Paquita Zuidema, Janek Uin, ChongaiKuang, Art Sedlacek, Steve Howell, Steffen Freitag, Amie Dobracki, Mary Kacarab, , Jenny
Wong, Thanos Nenes and the LASIC & ORACLES Science teams
Funding Sources:
1
![Page 2: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/2.jpg)
WRF-CAM5• Obtained through collaboration with Yang Zhang (NC state)
and Ruby Leung (PNNL)• WRF-Chem with CAM5 aerosol and physics:
– MAM3 aerosols (3 aerosol modes)– Fountoukis and Nenes (FN) series cloud droplet activation
(includes giant CCN and dust activation), Niemand et al. (2012) ice nucleation
– UW (Bretherton and Park) Boundary layer scheme– CESM cloud microphysics and cumulus scheme, shallow
cumulus scheme TURNED OFF
36 km resolution
• 36km horizontal, 72 vertical layers, 50 layers below 3km
• QFED Smoke emissions, no inversion, no plume rise
• Started every 5 days from FNL with 3 days of spin-up for each initialization, aerosol initial conditions from previous cycle
2
![Page 3: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/3.jpg)
Ascension black carbon during AugustModel histogram
Obs histogram
ObsFire ONFire OFF
ObsFire ONFire OFF
Model histogram
Obs histogram
2016
2017
3
![Page 4: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/4.jpg)
Computing hygroscopicity parameter (κ)
• Need observed CCN and size distribution
• Integrate the size distribution from the largest bin down to the critical diameter (dc) that matches the measured CCN concentration
• κ can be derived based on CCN supersaturation (SS) and critical diameter
Diameter
Petters and Kreidenweis, ACP 2007
Coun
ts [
#/cc
]
dc
4
![Page 5: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/5.jpg)
Size distribution from LASIC• Can be obtained from
SMPS or UHSAS• UHSAS probably needs
diameter correction due to:– Different refractive
index of aerosol used for calibration (e.g., Brock et al., ACP 2016)
– Potential evaporation of OA (U of Hawaii findings)
• Use SMPS scaled to total aerosol number concentration from CPC(>10nm) over the SMPS scan
% diff CPC-SMPS (Aug 2017)
5
![Page 6: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/6.jpg)
CCN from LASIC • Two columns
– CCNa: 0.1-1.0 SS
– CCNb: 0.4 SS• CCN is often
larger than CPC• Normalize CCN
to match CPC when CCN 0.8 SS ~ CCN 1.0 SS using single correction factor (~12%)
% diff CPC-CCN (Aug 2017)
CPC(10>nm) [#/cc] (Aug 2017)
6
![Page 7: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/7.jpg)
Modeled vs observed κ
(accum. mode)
• Range and variability of κ is similar in model and obs
• Modeled increases in κ during high smoke driven by increases in sea salt and sulfate fraction
7
highmedium low highSmoke load in MBL:
BC
κ
Model fractional composition of accumulation mode
![Page 8: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/8.jpg)
What drives changes in observed κ?
8
Κ (accum. mode)
CPC(10>nm)highmedium low highSmoke load in MBL:
![Page 9: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/9.jpg)
What drives changes in observed κ?
9
Κ by SS
highmedium low highSmoke load in MBL:
High smoke loadMedium smoke load
![Page 10: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/10.jpg)
Next steps
• Assess model representation of the nucleation mode
• Evaluate the model for other variables related to aerosol-cloud interactions: CCN concentrations, vertical velocities, cloud number droplet concentration
• Compare to observations from ORACLES/CLARIFY that took place in the free-troposphere
Thanks! Questions/[email protected] 10
![Page 11: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/11.jpg)
Supporting slides
11
![Page 12: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/12.jpg)
SMPS vs UHSAS critical diameter and kappa
12
![Page 13: Hygroscopicity parameter from LASIC observations and ......and Ruby Leung (PNNL) • WRF-hemC with CAM5 aerosol and physics: – MAM3 aerosols (3 aerosol modes) – Fountoukis and](https://reader033.vdocuments.us/reader033/viewer/2022052103/603d9374e8f0652b867dcdf3/html5/thumbnails/13.jpg)
Mean diameter and GSD evaluation
13