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What is the relationship between aerosol concentration, clouds, and precipitation?

ACID Group:

Shy Afanador

Hasnaa Hossam

Lucas Hornung

Shujun Zhou

Shan Gu

Shreya Joshi

Mirtha Allain

Ruoyu Zhang

DATA 23/05/2025

Mentors:

Sid Gupta

Sean Freeman

Chongai Kuang

Bill Gustafson

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Structure of talk

Shy: @shy: Talk about when convection and precipitation: Cloud, Storm and rain on May 9 night
Mirtha:Talk about how size distribution is changing and why. 30 seconds. Size distribution changes evening of 9
Shujun: CCN concentration: Particles are less activating after 9 eve
When is precipitation
Shreya: What particles we see BC particles. Support same observation
Shan: The source of particles change.
Possible explanation is : Random change in source of aerosols or the rain is scavenging the more activating particles that is hence causing the particles to be less activating

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Time

Seinfeld J H, ea.al. PNAS, 2016，

B Stevens, et.al. Nature, 2009.

More and Smaller CCN

Increased CCN creates more, smaller droplets, distributing the same water content among many particles.

Reflecting More Sunlight

Smaller droplets increase cloud surface area,

scattering more sunlight back into space.

Lifetime Effect

Smaller droplets reduce rainfall formation, extending cloud lifetime and decreasing precipitation.

Introduction

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Reflectivity and Vertical Speeds

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Cloud Contents

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Cloud Contents

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Time period

[2]

[3]

[4]

[5]

[6]

[1]

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Aerosol concentration

[3]

[6]

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Chemical composition

[3]

[6]

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Cell Tracking

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Aerosol size distribution

[1]

[2]

[3]

[4]

[5]

[6]

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Particles are less activating after May 9, 09 UTC, WHY?

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Extinction coefficient

Scattering coefficient

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More scattering

More burning contribution

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Particles are less activating after May 9, 09 UTC, due to the increase black carbon.

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48-hour HYSPLIT Back Trajectories Ending on May 9th at 00:00 UTC (Tracing Back to May 7th)

Air parcels originate predominantly from the southwest across all altitudes, with limited pressure variation observed along the trajectories, indicating minimal vertical displacement during transport.

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Limited pressure change along the trajectories in all altitudes indicating predominantly horizontal transport with minimal vertical displacement.

48-hour HYSPLIT Back Trajectories Ending on May 10th at 00:00 UTC (Tracing Back to May 8th)

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On May 10th, 2025, evidence from multi-platform observations over the BNF site indicates active aerosol-cloud interactions associated with vertically transported air masses.

The trajectory of 1000 - 2000m exhibit a clear pressure drop, indicating upward motion favorable for cloud condensation.

Previous radar reflectivity confirm intense cloud development and hydrometeor growth.�
Consistent with wind profile with increasing vertical wind speeds and directional shear. �
transported aerosols were entrained into the cloud system, activated as CCN, and participated in deep cloud evolution and potential precipitation formation on May 10.�

48-hour HYSPLIT Back Trajectories Ending on May 11th at 00:00 UTC (Tracing Back to May 9th)

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96-hour HYSPLIT Back Trajectories Ending on May 11th at 00:00 UTC (Tracing Back to May 7th)

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Conclusion

The clouds and storm build up on the 9-10th May.
The aerosol properties change between the days.
9th May acts as a transition period.
The clouds could be causing less activating interstitial particles through scavenging or a random change in particle source

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References

Sid Gupta, Sean Freeman, Chongai Kuang and Bill Gustafson

Koontz, A., Sedlacek, A., & Smith, S. Cavity Attenuated Phase Shift Extinction Monitor (AOSCAPS3W), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL,USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1406888

Kuang, C., Singh, A., Howie, J., Salwen, C., & Hayes, C. Scanning mobility particle sizer (AOSSMPS), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1476898

Koontz, A., Flynn, C., Uin, J., Jefferson, A., Andrews, E., Salwen, C., & Hayes, C. Nephelometer (AOSNEPHDRY), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1228051

Kyrouac, J., Shi, Y., & Tuftedal, M. Surface Meteorological Instrumentation (MET), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility.

https://doi.org/10.5439/1786358

Sedlacek, A., & Ermold, B. Single Particle Soot Photometer (AOSSP2XR), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/2507427

Koontz, A., Uin, J., Andrews, E., Enekwizu, O., Hayes, C., & Salwen, C. Cloud Condensation Nuclei Particle Counter (AOSCCN2COLA), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1323892

Koontz, A., Uin, J., Andrews, E., Enekwizu, O., Hayes, C., & Salwen, C. Cloud Condensation Nuclei Particle Counter (AOSCCN2COLB), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1323893

Koontz, A., Kuang, C., Andrews, E., Hayes, C., Singh, A., & Salwen, C. Condensation Particle Counter (AOSCPCF), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1352536

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References

Zhu, Z. Video Disdrometer (VDIS), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL,AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1992988

Keeler, E., Burk, K., & Kyrouac, J. Balloon-Borne Sounding System (SONDEWNPN),2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1595321

Shippert, T., Newsom, R., Riihimaki, L., & Zhang, D. Doppler Lidar VerticalVelocity Statistics (DLPROFWSTATS4NEWS), 2025-05-08 to 2025-05-11, BankheadNational Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead NationalForest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1178583

Feng, Y.-C., Lindenmaier, I., Matthews, A., Wendler, T., Melo de Castro, V.,Deng, M., & Rocque, M. Ka ARM Zenith Radar (KAZR2CFRGE), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF),Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1891991

Hardin, J., Giangrande, S., & Zhou, A. Laser Disdrometer Quantities (LDQUANTS),2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1432694

Newsom, R., & Zhang, D. Raman LIDAR Vertical Profiles (RLPROFMERGE2NEWS),2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1325950

Kyrouac, J., Shi, Y., & Tuftedal, M. Surface Meteorological Instrumentation (MET), 2025-05-08 to 2025-05-11, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (Main Site) (M1).Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1786358

Bharadwaj, N., Collis, S., Hardin, J., Isom, B., Lindenmaier, I., Matthews, A., Nelson, D., Feng, Y.-C., Rocque, M., Wendler, T., & Castro, V. C-Band Scanning ARM Precipitation Radar (CSAPR2CFR), 2025-05-08 to 2025-05-09, Bankhead National Forest, AL, USA; Long-term Mobile Facility (BNF), Bankhead National Forest, AL, AMF3 (for CSAPR2 near Main Site) (S3). Atmospheric Radiation Measurement (ARM) User Facility. https://doi.org/10.5439/1467901

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