Aerosols, Clouds, Convection, andPrecipitation (ACCP)
Orbital Summary✓✓✓Traceability to 2017 NASA Decadal Survey
Weather & Air Quality Panel

Climate Variability and Change Panel

Hydrological Cycle Panel

W-1 (MI): Planetary Boundary
Layer Dynamics.

C-2 (MI): Climate Feedbacksand Forcings.

H-1 (MI): Coupling the Water
and Energy Cycles.

W-2 (MI): Larger Range
Environmental Predictions.

C-5 (I-VI): Aerosols and Aerosol
Cloud Interactions.

C-8 (I): Causes and Effects ofPolar Amplification.

W-4 (MI): Convective StormFormation Processes.

W-5 (MI): Air Pollution
Processes and Distribution.
W-6 (I): Air Pollution Processes
and Trends.
W-9 (I): Role of Cloud
Microphysical Processes.
W-10 (I): Clouds and RadiativeForcing.

Most Important
Very Important
Important

DS Science Themes

Overarching Goal
Characterize the Role of Aerosols, Clouds, & Precipitationin Weather, Climate, and Air Quality Prediction

W-4 Convective Storm Processes

W-5 Air Quality Processes
and Distribution

C-2 Climate Sensitivity:
Cloud Feedback, Aerosol Forcing

Small Scale Processes
DS Science Questions

Condensation
Collision/Coalescence
Riming/Freezing
Precipitation

W-4 Convective Storm ProcessesEmissions
Humidification(Chemical Transformations)

W-5 Air Quality Processes
and Distribution

Nucleation, Condensation
Collision/Coalescence
Precipitation

C-2 Climate Sensitivity:
Cloud Feedback, Aerosol Forcing

Large Scale Processes
Small Scale Processes
DS Science Questions

GlobalAir-quality

Condensation
Collision/Coalescence
Riming/Freezing
Precipitation

W-4 Convective Storm Processes

Large-scale
Transport

Emissions
Humidification(Chemical Transformations)

W-5 Air Quality Processes
and Distribution

Nucleation, Condensation
Collision/Coalescence
Precipitation

C-2 Climate Sensitivity:
Cloud Feedback, Aerosol Forcing

Measurement Needs
Large Scale Processes
Small Scale Processes
DS Science Questions

GlobalAir-quality

Vertical Motion
Cloud &Precipitation Properties
Rainfall Extremes
Latent HeatingCondensation
Collision/Coalescence
Riming/Freezing
Precipitation

W-4 Convective Storm Processes

Large-scale
Transport

Aerosol Properties
Cloud/Precipitation Properties
Radiative Fluxes

Aerosol Microphysicaland Radiative Properties

Emissions
Humidification(Chemical Transformations)

W-5 Air Quality Processes
and Distribution

Nucleation, Condensation
Collision/Coalescence
Precipitation

C-2 Climate Sensitivity:
Cloud Feedback, Aerosol Forcing

Large Scale Processes

Measurement Needs

minuteAerosol Properties
Cloud/Precipitation Properties
Radiative Fluxes

Nucleation, Condensation
Collision/Coalescence
Precipitation

Emissions
Humidification(Chemical Transformations)

W-4 Convective Storm Processes

secondLarge-scale
Transport

Aerosol Microphysicaland Radiative Properties

Condensation
Collision/Coalescence
Riming/Freezing
Precipitation

Small Scale Processes
DS Science Questions

GlobalAir-quality

Vertical Motion
Cloud &Precipitation Properties
Rainfall Extremes
Latent Heating

C-2 Climate Sensitivity:
Cloud Feedback, Aerosol Forcing

W-5 Air Quality Processes
and Distribution

hourdayweekmonthyearcentury

Architecture Recommendation—Dual Orbit Constellation

Science Implementation Strategies

Polar Orbit
Inclined Orbit

Inclined Orbit

1st launch of inclined orbit ~2028
2nd launch of polar orbit ~2029-30

Inclined Orbit• W-, Ku-band Doppler radar• Microwave radiometer (118-880 GHz)
• 532 and 1064 nm backscatter lidar• Polarimeter (> 5 angles, > 6 channels)• Time-differenced tandem stereo camera
Polar Orbit• W- & Ka-band Doppler radar• Microwave radiometer (118-880 GHz)
• 532 nm HSRL, 1064 nm backscatter lidar• Polarimeter (550 km swath, 0.5 km resolution)• Spectrometers (UV-VIS-NIR-SWIR, LWIR-FIR)→ LWIR-FIR Spec. contributed by CSA

The 5 “First-Evers” of ACCP
1. Global Observations of Convective
Vertical Motion
2. Global Profiles of Aerosol Properties(absorption, type, size, number)
3. Co-located Dynamics, Cloud AND
Precipitation Microphysics and Aerosol
Characteristics
4. Low Cloud and Aerosol Plume Dynamics
5. Diurnal Variability of Clouds and Aerosols

Doppler Capabilities
Next generation Doppler technology

W-Band Doppler Velocity

Polar: WD, KaD band with dual antennas(displaced phase center antenna)
Inclined: W (single antenna), KuD (DPCA)

Ka-Band Doppler Velocity

WRF Model Truth
JAXA
Ku-Band
Doppler
Velocity
Ku-Band
Doppler
Velocity

Radar simulations performed by Pavlos Kollias

051015km

202503051015km

2025

Radar: Profiling Near-Surface Precipitation-30-16-9-2-30

50.9

0.9

0.0
05-30

10-23

15km

-1620-925-2

30

5dBZ

km

0.60.0-2

ACCP Radar
radar13+resolution

0.90.3-9

CloudSat resolution
1.20.3-16dBZ

1.20.6-23dBZ

1.2kmkm40x50 m resolution-230.605-30

10-2315km-162025-9-2300.0051015km

2025-30-23-16

CloudSat
CloudSat

Simulation ofCloudSat
CloudSatresolution
and candidate A/CCP
1.2
radar
sampling for a DYCOMS-II RF02

-9-2

ACCP
radarRadar
13+

1000

1000

800

800

0-30

510-2315km-1620-925-2dBZ

Courtesy of Matt Lebsock

30

600

Height [km]0.0Height [km]km0.90.6

Cloud Base

400

600

Cloud Base

400

52000-30

200-20-10dBZ

01030

5dBZ

0.3

50.3dBZ

Sacrificing detection sensitivity
to achieve higher resolution
improves near surface profiling

300-30-20-10dBZ

0105Lidar Capabilities (Daytime)
CALIPSO Simulation
Aircraft dataCirrus Clouds

Aerosol Layer
ACCP-Backscatter Lidar Simulation

ACCP-HSRL Simulation

Simulations produced by ACCP Lidar Working GroupMotion Field from Tandem Stereo Cameras
From time-differenced cloudtop measurements (40 meter
footprint, 100 km swath):

Horizontal wind field

Horizontal divergence field

Cloud-top vertical motions
From R. Marchand, A. Davis, L. Forster, and M. Kurowski

Summary• ACCP study initiated in 2018 with involvement of 5 NASA centers + academia• JAXA, CNES, CSA, and DLR also participated in the study• Study concluded in April 2021
• > 15 architecture concepts studied in some detail• Top 3 architectures submitted to NASA HQ with recommendation for dual-orbit concept• Several ACCP elements:• Orbital• Sub-orbital• Modeling• ACCP is envisioned as one element of an Earth Observing system, combined with:• PoR (Geo-Ring, etc)
• Surface, Biology and Geology (SBG), Mass Change, Surface Deformation