Instrument

CAPS
Cloud Aerosol and Precipitation Spectrometer

The Cloud Aerosol and Precipitation Spectrometer (CAPS) is an in situ airborne spectrometer manufactured by Droplet Measurement Technologies. It combines the Cloud Imaging Probe (CIP), the Cloud and Aerosol Spectrometer (CAS), and the Hotwire Liquid Water Content (LWC) Sensor into a single instrument. CAPS measures the size distribution of aerosols, clouds, and liquid particles from 50 to 1600 μm, with a data collection rate of 1 Hz. It can also capture images of cloud particles and measure temperature, pressure, and LWC.

NASA's DC-8 flying laboratory passes Antarctica's tallest peak, Mount Vinson, on Oct. 22, 2012, during a flight over the continent to measure changes in the massive ice sheet and sea ice. Credit: NASA/Michael Studinger (Photography courtesy NASA Images)

Overview

Instrument Details

Measurement Type

Spectrometer/Radiometer

Measurement/Variables

Earth Science > Atmosphere > Aerosols

Earth Science > Atmosphere > Aerosols > Aerosol Particle Properties

Earth Science > Atmosphere > Clouds > Cloud Microphysics > Particle Size Distribution

Earth Science > Atmosphere > Precipitation > Droplet Size

Earth Science > Atmosphere > Clouds > Cloud Microphysics > Cloud Droplet Concentration/size

Earth Science > Atmosphere > Clouds > Cloud Microphysics

Earth Science > Atmosphere > Precipitation

Earth Science > Atmosphere > Clouds > Cloud Microphysics > Cloud Liquid Water/ice

Earth Science > Atmosphere > Clouds

Vertical Measurement Regions

Troposphere

Temporal Resolution

1 Hz

Spatial Resolution

Point

Measurement Frequency

438 THz

Calibration Details

https://www.arm.gov/publications/tech_reports/handbooks/doe-sc-arm-tr-246.pdf

Online Information

Lead Investigator
Andrew Heymsfield
Technical Contact
Andrew Heymsfield
Instrument Maker
Droplet Measurement Technologies
Funding Source
Office of Naval Research Small Business Innovation Research Program
Overview Publications
Overview Publication
Repositories
- Atmospheric Science Data Center (ASDC)
- Global Hydrology Resource Center DAAC (GHRC)

Instrument Operation

Platform

Campaigns, where the platform was used with this instrument

DC-8

Douglas DC-8

46 Campaigns · 184 Instruments

GRIP

Genesis and Rapid Intensification Processes

2010

Tropical Atlantic, Gulf of Mexico, Eastern North Pacific, Caribbean Sea

view all deployment dates

· 24 Data Products

SARP

Student Airborne Research Program

2009—2025

Southern California, Virginia

Ongoing

view all deployment dates

Deployment Dates

Start Date	End Date
2025-06-15	2025-08-02
2025-06-22	2025-08-09
2009-07-12	2009-08-13
2010-06-20	2010-07-30
2011-06-19	2011-07-29
2012-06-17	2012-08-10
2013-06-09	2013-08-02
2014-06-15	2014-08-08
2015-06-14	2015-08-07
2016-06-12	2016-08-05
2017-06-18	2017-08-11
2018-06-18	2018-08-10
2019-06-16	2019-08-09
2021-12-03	2021-12-10
2022-06-12	2022-08-05
2023-06-11	2023-08-04
2023-06-18	2023-08-11
2024-06-16	2024-08-09
2024-06-23	2024-08-16

· 25 Data Products

ARCTAS

Arctic Research of the Composition of the Troposphere from Aircraft and Satellites

2008

Alaska, Western Canada, California

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· 27 Data Products

NAMMA

NASA African Monsoon Multidisciplinary Analyses

2006

Cape Verde Islands, Atlantic Ocean

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· 22 Data Products

TC4

Tropical Composition, Cloud and Climate Coupling

2007

Costa Rica, tropical Eastern Pacific

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· 2 Data Products

ATom

Atmospheric Tomography Mission

2016—2018

Western Arctic, South Pacific, Atlantic Ocean, Greenland, Central North America

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· 56 Data Products

AMISA

Arctic Mechanisms of Interaction Between the Surface and Atmosphere

2008

Arctic: Scandinavia and Greenland

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· 0 Data Products

FIREX-AQ

Fire Influence on Regional to Global Environments and Air Quality

2019

Northwestern and Southeastern US

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· 27 Data Products

TRACE

Transport and Atmospheric Chemistry near the Equator

1992—2001

Brazil, Southern Africa, Tropical Atlantic, Central & Western Regions of the Pacific Ocean Basin

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· 25 Data Products

AEROMMA

Atmospheric Emissions and Reactions Observed from Megacities to Marine Areas

2023

Urban regions across the western and eastern United States

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· 0 Data Products

CPEX-CV

Convective Processes EXperiment - Cabo Verde

2022

Cabo Verde, Tropical East Atlantic Ocean

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· 10 Data Products

SOLVE

SAGE III Ozone Loss and Validation Experiment

1999—2003

Arctic, Kiruna, Sweden

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· 32 Data Products

DICE

DC-8 Inlet Characterization Experiment

2003

California

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· 0 Data Products

B-200

Beechcraft B-200 King Air

41 Campaigns · 87 Instruments

LPVEx

Light Precipitation Evaluation Experiment

2010

Gulf of Finland

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· 22 Data Products

KORUS-AQ

Korean United States - Air Quality

2016

South Korean peninsula, including surrounding seas

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· 20 Data Products

SARP

Student Airborne Research Program

2009—2025

Southern California, Virginia

Ongoing

view all deployment dates

Deployment Dates

Start Date	End Date
2025-06-15	2025-08-02
2025-06-22	2025-08-09
2009-07-12	2009-08-13
2010-06-20	2010-07-30
2011-06-19	2011-07-29
2012-06-17	2012-08-10
2013-06-09	2013-08-02
2014-06-15	2014-08-08
2015-06-14	2015-08-07
2016-06-12	2016-08-05
2017-06-18	2017-08-11
2018-06-18	2018-08-10
2019-06-16	2019-08-09
2021-12-03	2021-12-10
2022-06-12	2022-08-05
2023-06-11	2023-08-04
2023-06-18	2023-08-11
2024-06-16	2024-08-09
2024-06-23	2024-08-16

· 25 Data Products

Vehicle

21 Campaigns · 68 Instruments

DISCOVER-AQ

Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality

2011—2014

Baltimore MD, San Joaquin Valley CA, Houston TX, Denver CO

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· 77 Data Products

FIREX-AQ

Fire Influence on Regional to Global Environments and Air Quality

2019

Northwestern and Southeastern US

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· 27 Data Products

MOOSE

Michigan-Ontario Ozone Source Experiment

2021

Southern Ontario, Southeastern Michigan

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· 2 Data Products

Mooney

Mooney Ovation

2 Campaigns · 5 Instruments

LMOS

Lake Michigan Ozone Study

2017

Lake Michigan

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· 13 Data Products

WB-57

NASA WB-57

17 Campaigns · 84 Instruments

TC4

Tropical Composition, Cloud and Climate Coupling

2007

Costa Rica, tropical Eastern Pacific

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· 2 Data Products

CR-AVE

Costa Rica Aura Validation Experiment

2006

Costa Rica

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· 0 Data Products

MidCiX

Middle Latitude Cirrus Experiment

2004

South-central United States

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· 0 Data Products

CRYSTAL-FACE

Cirrus Regional Study of Tropical Anvils and Cirrus Layers Florida Area Cirrus Experiment

2002

Southern Florida

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· 0 Data Products

SABRE

Stratospheric Aerosol processes, Budget, and Radiative Effects

2022—2025

Houston, Texas, Fairbanks, Alaska

Ongoing

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· 0 Data Products

ACCLIP

Asian Summer Monsoon Chemical & Climate Impact Project

2022

West Pacific, South Korea

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· 8 Data Products

Onnuri

R/V Onnuri

2 Campaigns · 9 Instruments

KORUS-AQ

Korean United States - Air Quality

2016

South Korean peninsula, including surrounding seas

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· 20 Data Products

KORUS-OC

Korea-United States Ocean Color Study

2016

South Korea, Yellow Sea, East Sea

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· 5 Data Products

Twin Otter

DeHavilland DHC-6-300 Twin Otter

23 Campaigns · 85 Instruments

CRYSTAL-FACE

Cirrus Regional Study of Tropical Anvils and Cirrus Layers Florida Area Cirrus Experiment

2002

Southern Florida

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· 0 Data Products

CLASIC07

Cloud and Land Surface Interaction Campaign 2007

2007

Southern Great Plains, Oklahoma, Kansas

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· 7 Data Products

PACE-PAX

Plankton, Aerosol, Cloud, ocean Ecosystem Postlaunch Airborne eXperiment

2024

Southern and Central California

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· 15 Data Products

G-1

Gulfstream-159

4 Campaigns · 45 Instruments

CalWater

2015

California, Sierra Nevada Range

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· 0 Data Products

MILAGRO

Megacity Initiative: Local and Global Research Observations

2006

Mexico City Metropolitan Area

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· 0 Data Products

CARES

Carbonaceous Aerosol and Radiative Effects Study

2010

Central Valley, California

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· 0 Data Products

CHAPS

Cumulus Humilis Aerosol Process Study

2007

Oklahoma City, Oklahoma

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· 0 Data Products

P-3

P-3 Orion

31 Campaigns · 153 Instruments

IMPACTS

Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms

2020—2023

Eastern United States

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· 73 Data Products

Image of a FLUXNET tower in Harvard Forests, Maine

Permanent Land Site

Stationary

67 Campaigns · 103 Instruments

PACE-PAX

Plankton, Aerosol, Cloud, ocean Ecosystem Postlaunch Airborne eXperiment

2024

Southern and Central California

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· 15 Data Products

G-II

Gulfstream II

1 Campaign · 13 Instruments

Wakasa Bay Experiment

2003

Wakasa Bay, Japan, Sea of Japan, Western Pacific Ocean

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· 0 Data Products

Data Products

Filter data products from this instrument by specific campaigns, platforms, or formats.

Campaigns

Platforms

Formats

GRIP CLOUD MICROPHYSICS V1http://dx.doi.org/10.5067/GRIP/MULTIPLE/DATA201

CampaignsGenesis and Rapid Intensification Processes

PlatformsDouglas DC-8

NAMMA CLOUD MICROPHYSICS (CAPS-PIP) V1http://dx.doi.org/10.5067/NAMMA/PROBES/DATA201

CampaignsNASA African Monsoon Multidisciplinary Analyses

PlatformsDouglas DC-8

LMOS Scientific Aviation In-Situ Data10.5067/Suborbital/LMOS/AircraftInSitu_ScientificAviation_Data_1

CampaignsLake Michigan Ozone Study

PlatformsMooney Ovation

GPM GROUND VALIDATION WYOMING KING AIR CLOUD MICROPHYSICS LPVEX V1http://dx.doi.org/10.5067/GPMGV/LPVEX/MULTPLE/DATA202

CampaignsLight Precipitation Evaluation Experiment

PlatformsBeechcraft B-200 King Air

SOLVE II DC-8 Aircraft In-situ Aerosol Data10.5067/ASDC/SUBORBITAL/SOLVE2_Aerosol_AircraftInSitu_DC8_Data_1

CampaignsSAGE III Ozone Loss and Validation Experiment

PlatformsDouglas DC-8

FormatsOther Ames

INTEXA_DC8_AIRCRAFT10.5067/ASDCDAAC/INTEXA/0008

CampaignsIntercontinental Chemical Transport Experiment - North America

PlatformsDouglas DC-8

FIREX-AQ DC-8 In-Situ Cloud Data10.5067/ASDC/FIREXAQ_Cloud_AircraftInSitu_DC8_Data_1

CampaignsFire Influence on Regional to Global Environments and Air Quality

PlatformsDouglas DC-8

FormatsICARTT

FIREX-AQ MACH2 Surface Mobile In-Situ Measurements10.5067/ASDC/FIREXAQ_SurfaceMobile_MACH2_InSitu_Data_1

CampaignsFire Influence on Regional to Global Environments and Air Quality

PlatformsVehicle

FormatsICARTT

FIREX-AQ Merge Data Files10.5067/ASDC/FIREXAQ_Merge_Data_2

CampaignsFire Influence on Regional to Global Environments and Air Quality

PlatformsDouglas DC-8

FormatsICARTT

FIREX-AQ DC-8 In-Situ Aerosol Data10.5067/ASDC/FIREXAQ_Aerosol_AircraftInSitu_DC8_Data_1

CampaignsFire Influence on Regional to Global Environments and Air Quality

PlatformsDouglas DC-8

FormatsICARTT

ACCLIP WB-57 Aircraft In-situ Cloud Data10.5067/ASDC/SUBORBITAL/ACCLIP_Cloud_AircraftInSitu_WB57_Data_1

CampaignsAsian Summer Monsoon Chemical & Climate Impact Project

PlatformsNASA WB-57

FormatsICARTT

ARCTAS DC-8 Aircraft In-situ Cloud Data10.5067/ASDC/SUBORBITAL/ARCTAS_Cloud_AircraftInSitu_DC8_Data_1

CampaignsArctic Research of the Composition of the Troposphere from Aircraft and Satellites

PlatformsDouglas DC-8

FormatsICARTT

MOOSE Aerodyne Mobile Laboratory Measurements10.5067/ASDC/SUBORBITAL/MOOSE/DATA001/Aerodyne-Mobile-Lab_1

CampaignsMichigan-Ontario Ozone Source Experiment

PlatformsVehicle

FormatsICARTT

DISCOVER-AQ Colorado Deployment Mobile Platform Data10.5067/ASDC/SUBORBITAL/DISCOVERAQ_Colorado_Ground_Mobile_Data_1

CampaignsDeriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality

PlatformsVehicle

FormatsICARTT

ATom: Cloud and Coarse Aerosol Measurements from CAPS Instrument, 2016-201810.3334/ORNLDAAC/1981

CampaignsAtmospheric Tomography Mission

PlatformsDouglas DC-8

FormatsICARTT

PACE-PAX Marina Tower In-Situ Aerosol Data10.5067/ASDC/SUBORBITAL/PACE-PAX/Marina-Tower/LARGE-Aerosol_1

CampaignsPlankton, Aerosol, Cloud, ocean Ecosystem Postlaunch Airborne eXperiment

PlatformsPermanent Land Site

FormatsICARTT

SARP 2021 Data10.5067/SUBORBITAL/SARP/DATA001/2021

CampaignsStudent Airborne Research Program

PlatformsDouglas DC-8

FormatsICARTT

SARP-East 2023 Data10.5067/SUBORBITAL/SARP/DATA001/SARP-EAST/2023

CampaignsStudent Airborne Research Program

PlatformsBeechcraft B-200 King Air, Field Site, Balloon Launch Site

FormatsICARTT, netCDF

KORUS-AQ Environmental Protection Agency (EPA) Ground Site Data10.5067/ASDC/SUBORBITAL/KORUSAQ_Ground_EPA_Data_1

CampaignsKorean United States - Air Quality

PlatformsField Site

FormatsHDF, ICARTT

ATom: Merged Atmospheric Chemistry, Trace Gases, and Aerosols10.3334/ORNLDAAC/1581

CampaignsAtmospheric Tomography Mission

PlatformsDouglas DC-8

FormatsnetCDF

ATom: Black Carbon Mass Mixing Ratios from ATom-1 Flights10.3334/ORNLDAAC/1618

CampaignsAtmospheric Tomography Mission

PlatformsDouglas DC-8

FormatsCSV

ATom: In-Situ Measurements of Airflow and Aerosols from Multiple Airborne Campaigns10.3334/ORNLDAAC/1784

CampaignsAtmospheric Tomography Mission

PlatformsDouglas DC-8

FormatsCSV

ATom: Merged Atmospheric Chemistry, Trace Gases, and Aerosols, Version 210.3334/ORNLDAAC/1925

CampaignsAtmospheric Tomography Mission

PlatformsDouglas DC-8

FormatsnetCDF

CAPSCloud Aerosol and Precipitation Spectrometer

Overview

Instrument Details

Instrument Operation

Data Products

CAPS
Cloud Aerosol and Precipitation Spectrometer