Instrument

DLH
Diode Laser Hygrometer

The Diode Laser Hygrometer (DLH) is an in situ airborne hygrometer developed by NASA’s Langley Research Center (LaRC). It uses tunable diode laser absorption to measure atmospheric water vapor. DLH operates in the near-infrared at around 1.4 μm and has a measurement rate of 100 Hz. It provides accurate water vapor measurements even when flying through clouds.

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

Temperature/Humidity

Measurement/Variables

Earth Science > Atmosphere > Atmospheric Water Vapor

Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Water Vapor

Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity > Relative Humidity

Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity

Vertical Measurement Regions

Lower Stratosphere, Troposphere

Temporal Resolution

100 Hz

Spatial Resolution

Point

Measurement Frequency

214 THz

Calibration Details

https://doi.org/10.1029/2002JD003156

Online Information

https://airbornescience.nasa.gov/instrument/Diode_Laser_Hygrometer

Lead Investigator
Glenn S. Diskin
Technical Contact
Glenn S. Diskin
Instrument Maker
LaRC
Funding Source
Currently unavailable
Overview Publications
Overview Publication
Repositories
- Atmospheric Science Data Center (ASDC)
- Oak Ridge National Laboratory DAAC (ORNL)

Instrument Operation

Platform

Campaigns, where the platform was used with this instrument

DC-8

Douglas DC-8

46 Campaigns · 184 Instruments

SEAC4RS

Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys

2013

North America including portions of Canada, Mexico and the Gulf of Mexico

view all deployment dates

· 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

· 26 Data Products

INTEX-NA

Intercontinental Chemical Transport Experiment - North America

2004—2006

North America, Gulf of Mexico, North Pacific Ocean, North Atlantic Ocean

view all deployment dates

· 21 Data Products

DC3

Deep Convective Clouds & Chemistry

2012

Northeastern Colorado, West Texas to Central Oklahoma, Northern Alabama

view all deployment dates

· 19 Data Products

ARCTAS

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

2008

Alaska, Western Canada, California

view all deployment dates

· 27 Data Products

NAMMA

NASA African Monsoon Multidisciplinary Analyses

2006

Cape Verde Islands, Atlantic Ocean

view all deployment dates

· 22 Data Products

TEFLUN

TExas and FLorida UNderflights

1998

Texas, Florida

view all deployment dates

· 0 Data Products

TC4

Tropical Composition, Cloud and Climate Coupling

2007

Costa Rica, tropical Eastern Pacific

view all deployment dates

· 3 Data Products

KORUS-AQ

Korean United States - Air Quality

2016

South Korean peninsula, including surrounding seas

view all deployment dates

· 20 Data Products

ATom

Atmospheric Tomography Mission

2016—2018

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

view all deployment dates

· 56 Data Products

FIREX-AQ

Fire Influence on Regional to Global Environments and Air Quality

2019

Northwestern and Southeastern US

view all deployment dates

· 28 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

view all deployment dates

· 25 Data Products

ASCENDS Airborne

Active Sensing of CO2 Emissions over Nights, Days, and Seasons

2010—2017

United States, Canada

view all deployment dates

· 5 Data Products

AEROMMA

Atmospheric Emissions and Reactions Observed from Megacities to Marine Areas

2023

Urban regions across the western and eastern United States

view all deployment dates

· 0 Data Products

PEM

Pacific Exploratory Mission

1991—1999

Pacific Ocean

view all deployment dates

· 51 Data Products

PAVE

Polar Aura Validation Experiment

2005

Northeastern United States, Eastern Canada

view all deployment dates

· 0 Data Products

IceBridge

Operation IceBridge

2009—2021

Greenland, Antarctica, Alaska, Arctic Sea

view all deployment dates

Deployment Dates

Start Date	End Date
2009-10-16	2010-02-16
2009-03-31	2009-06-02
2009-08-19	2009-09-06
2010-03-22	2010-05-26
2010-08-21	2010-08-29
2010-10-20	2011-02-26
2011-03-16	2011-05-30
2011-08-16	2011-09-12
2011-10-07	2011-12-23
2012-03-14	2012-05-24
2012-08-14	2012-08-30
2012-10-12	2013-01-26
2013-03-20	2013-05-28
2013-06-17	2013-08-30
2013-10-31	2013-11-14
2013-11-19	2013-11-28
2014-03-12	2014-05-24
2014-08-19	2014-08-23
2014-10-16	2014-11-22
2015-03-19	2015-05-22
2015-08-20	2015-08-29
2015-09-22	2015-10-29
2015-09-23	2015-10-22
2016-04-19	2016-05-28
2016-07-13	2016-09-15
2016-10-14	2016-11-18
2017-03-09	2017-05-31
2017-07-17	2017-09-20
2017-10-29	2017-12-16
2018-03-22	2018-05-30
2018-08-17	2018-08-29
2018-10-10	2018-11-16
2019-04-03	2019-05-16
2019-09-04	2019-09-28
2019-10-23	2019-11-20
2020-05-21	2020-06-13
2021-05-02	2021-05-13

· 82 Data Products

SONEX

Subsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment

1997

North Atlantic Ocean, Ireland, Newfoundland, Bangor, Maine, Azores

view all deployment dates

· 10 Data Products

SOLVE

SAGE III Ozone Loss and Validation Experiment

1999—2003

Arctic, Kiruna, Sweden

view all deployment dates

· 32 Data Products

HIWC

High Ice Water Content Radar Study

2015—2022

Southeastern United States, Florida, Atlantic Ocean, Gulf of Mexico, Southern California, Hawaii, Pacific Ocean

view all deployment dates

· 0 Data Products

ASIA-AQ

Airborne and Satellite Investigation of Asian Air Quality

2024

East and Southeast Asia, Philippines, South Korea, Thailand

view all deployment dates

· 8 Data Products

MILAGRO

Megacity Initiative: Local and Global Research Observations

2006

Mexico City Metropolitan Area

view all deployment dates

· 0 Data Products

TOTE-VOTE

Tropical Ozone Transport Experiment – Vortex Ozone Transport Experiment

1995—1996

Pacific Ocean, Hawaii, Alaska, Iceland, Arctic, Arctic Ocean

view all deployment dates

· 10 Data Products

Global Hawk

6 Campaigns · 30 Instruments

ATTREX

Airborne Tropical Tropopause Experiment

2011—2015

California, Guam, Tropics

view all deployment dates

· 5 Data Products

Citation

Cessna Citation II

11 Campaigns · 26 Instruments

MC3E

Mid-latitude Continental Convective Clouds Experiment

2011

Central Oklahoma, Southern Plains

view all deployment dates

· 34 Data Products

C-23 Sherpa

Short Brothers C-23 Sherpa

4 Campaigns · 22 Instruments

CARAFE

NASA Carbon Atmospheric Flux Experiment

2016—2017

Eastern United States Coast, Mid-Atlantic Region

view all deployment dates

· 1 Data Product

P-3

P-3 Orion

33 Campaigns · 154 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

view all deployment dates

· 77 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

· 26 Data Products

IMPACTS

Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms

2020—2023

Eastern United States

view all deployment dates

· 73 Data Products

ARCSIX

Arctic Radiation-Cloud-Aerosol-Surface Interaction EXperiment

2024

Greenland, Arctic Ocean

view all deployment dates

· 18 Data Products

CAMP2Ex

Clouds, Aerosol, and Monsoon Processes-Philippines Experiment

2019

Philippines

view all deployment dates

· 12 Data Products

MAGEQ

Mid-Atlantic Gas Emissions Quantification

2025

Mid-Atlantic United States

view all deployment dates

· 2 Data Products

Falcon

Dassault Falcon 20-E5

6 Campaigns · 44 Instruments

ACTIVATE

Aerosol Cloud meTerology Interactions oVer the western ATlantic Experiment

2020—2022

Western North Atlantic Ocean

view all deployment dates

· 12 Data Products

WB-57

NASA WB-57

18 Campaigns · 86 Instruments

POSIDON

Pacific Oxidants, Sulfur, Ice, Dehydration, and cONvection

2016

Guam, western Pacific

view all deployment dates

· 0 Data Products

NOVICE

Newly-Operating and Validated Instruments Comparison Experiment

2008

Houston, Texas

view all deployment dates

· 0 Data Products

MACPEX

Mid-latitude Airborne Cirrus Properties Experiment

2011

Central United States

view all deployment dates

· 7 Data Products

SABRE

Stratospheric Aerosol processes, Budget, and Radiative Effects

2022—2025

Houston, Texas, Fairbanks, Alaska

Ongoing

view all deployment dates

· 0 Data Products

ACCLIP

Asian Summer Monsoon Chemical & Climate Impact Project

2022

West Pacific, South Korea

view all deployment dates

· 8 Data Products

B-200

Beechcraft B-200 King Air

42 Campaigns · 87 Instruments

DEVOTE

Development and Evaluation of satellite ValidatiOn Tools by Experimenters

2011

Eastern and Southeastern United States

view all deployment dates

· 5 Data Products

Data Products

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

Campaigns

Platforms

Formats

INTEXA_DC8_AIRCRAFT10.5067/ASDCDAAC/INTEXA/0008

CampaignsIntercontinental Chemical Transport Experiment - North America

PlatformsDouglas DC-8

CAMP2Ex P-3 In-Situ Meteorological and Navigational Data10.5067/Airborne/CAMP2Ex_MetNav_AircraftInSitu_P3_Data_1

CampaignsClouds, Aerosol, and Monsoon Processes-Philippines Experiment

PlatformsP-3 Orion

FormatsICARTT

DC3 In-Situ DC-8 Meteorological and Navigational Data10.5067/ASDC/SUBORBITAL/DC3_MetNav_AircraftInSitu_DC8_Data_1

CampaignsDeep Convective Clouds & Chemistry

PlatformsDouglas DC-8

NAMMA DIODE LASER HYGROMETER (DLH) V1http://dx.doi.org/10.5067/NAMMA/HYGROMETER/DATA201

CampaignsNASA African Monsoon Multidisciplinary Analyses

PlatformsDouglas DC-8

GPM GROUND VALIDATION UND CITATION CLOUD MICROPHYSICS MC3E V1http://dx.doi.org/10.5067/GPMGV/MC3E/MULTIPLE/DATA201

CampaignsMid-latitude Continental Convective Clouds Experiment

PlatformsCessna Citation II

DEVOTE B-200 Aircraft In-Situ Meteorological and Navigational Data10.5067/ASDC/SUBORBITAL/DEVOTE_MetNav_AircraftInSitu_B200_Data_1

CampaignsDevelopment and Evaluation of satellite ValidatiOn Tools by Experimenters

PlatformsBeechcraft B-200 King Air

ACTIVATE Falcon In-Situ Meteorological and Navigational Data10.5067/ASDC/ACTIVATE_MetNav_AircraftInSitu_Falcon_Data_1

CampaignsAerosol Cloud meTerology Interactions oVer the western ATlantic Experiment

PlatformsDassault Falcon 20-E5

FormatsICARTT

FIREX-AQ DC8 In-Situ Meteorological and Navigational Data10.5067/ASDC/FIREXAQ_MetNav_AircraftInSitu_DC8_Data_1

CampaignsFire Influence on Regional to Global Environments and Air Quality

PlatformsDouglas DC-8

FormatsICARTT

KORUS-AQ DC-8 Aircraft In Situ Meteorological and Navigational Data10.5067/ASDC/SUBORBITAL/KORUSAQ_MetNav_AircraftInSitu_DC8_Data_1

CampaignsKorean United States - Air Quality

PlatformsDouglas DC-8

FormatsICARTT

CARAFE: Regional Airborne Greenhouse Gases Eddy Covariance Measurements, 2016-201710.3334/ORNLDAAC/2002

CampaignsNASA Carbon Atmospheric Flux Experiment

PlatformsShort Brothers C-23 Sherpa, Balloon Launch Site

MACPEX WB-57 Aircraft In-situ Water Data10.5067/ASDC/SUBORBITAL/MACPEX_Water_AircraftInSitu_WB57_Data_1

CampaignsMid-latitude Airborne Cirrus Properties Experiment

PlatformsNASA WB-57

SARP 2016 Data10.5067/SUBORBITAL/SARP/DATA001/2016

CampaignsStudent Airborne Research Program

PlatformsDouglas DC-8

FormatsICARTT

SEAC4RS DC-8 Aircraft In-Situ Meteorological and Navigational Data10.5067/ASDC/SUBORBITAL/SEAC4RS_MetNav_AircraftInSitu_DC8_Data_1

CampaignsStudies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys

PlatformsDouglas DC-8

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

SARP 2019 Data10.5067/SUBORBITAL/SARP/DATA001/2019

CampaignsStudent Airborne Research Program

PlatformsDouglas DC-8

FormatsICARTT, HDF

INTEXB_DC8_AIRCRAFT10.5067/ASDCDAAC/INTEXB/0008

CampaignsIntercontinental Chemical Transport Experiment - North America

PlatformsDouglas DC-8

ACCLIP WB-57 Meteorological and Navigational Data10.5067/ASDC/SUBORBITAL/ACCLIP_MetNav_AircraftInSitu_WB57_Data_1

CampaignsAsian Summer Monsoon Chemical & Climate Impact Project

PlatformsNASA WB-57

FormatsICARTT

Tropical Ozone Transport Experiment – Vortex Ozone Transport Experiment (TOTE-VOTE) In Situ DC-8 Meteorology and Navigation Data10.5067/ASDC/SUBORBITAL/TOTE-VOTE_MetNav_AircraftInSitu_DC8_Data_1

CampaignsTropical Ozone Transport Experiment – Vortex Ozone Transport Experiment

PlatformsDouglas DC-8

FormatsDC

SASS (Subsonics Assessment) Ozone and NOx Experiment (SONEX) DC-8 In-Situ Meteorological and Navigation Data

CampaignsSubsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment

PlatformsDouglas DC-8

FormatsAmes

SASS (Subsonics Assessment) Ozone and NOx Experiment (SONEX) Merge Data Files10.5067/ASDC/SUBORBITAL/SONEX_Merge_DC8_Data_1

CampaignsSubsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment

PlatformsDouglas DC-8

FormatsAmes

SOLVE I DC-8 Aircraft In-situ Meteorology and Navigational Data10.5067/ASDC/SUBORBITAL/SOLVE1_MetNav_AircraftInSitu_DC8_Data_1

CampaignsSAGE III Ozone Loss and Validation Experiment

PlatformsDouglas DC-8

FormatsOther Ames

SOLVE II DC-8 Aircraft In-situ Meteorology and Navigational Data10.5067/ASDC/SUBORBITAL/SOLVE2_MetNav_AircraftInSitu_DC8_Data_1

CampaignsSAGE III Ozone Loss and Validation Experiment

PlatformsDouglas DC-8

FormatsOther Ames

ACTIVATE Falcon Aircraft Merge Data Files10.5067/ASDC/SUBORBITAL/ACTIVATE_Merge_Data_1

CampaignsAerosol Cloud meTerology Interactions oVer the western ATlantic Experiment

PlatformsDassault Falcon 20-E5

FormatsICARTT

ARCTAS DC-8 Aircraft In-situ Meteorological and Navigational Data10.5067/ASDC/SUBORBITAL/ARCTAS_MetNav_AircraftInSitu_DC8_Data_1

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

PlatformsDouglas DC-8

FormatsICARTT

ATTREX Global Hawk UAS In-Situ Trace Gas Measurements10.5067/ASDC_DAAC/ATTREX/0003

CampaignsAirborne Tropical Tropopause Experiment

PlatformsGlobal Hawk

FormatsICARTT

CAMP2Ex P-3 In-Situ Trace Gas Data10.5067/Airborne/CAMP2Ex_TraceGas_AircraftInSitu_P3_Data_1

CampaignsClouds, Aerosol, and Monsoon Processes-Philippines Experiment

PlatformsP-3 Orion

FormatsICARTT

DISCOVER-AQ Maryland Deployment P-3B Aircraft In Situ Meteorological and Navigational Data10.5067/ASDC/SUBORBITAL/DISCOVERAQ_Maryland_MetNav_AircraftInSitu_P3B_Data_1

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

PlatformsP-3 Orion

FormatsICARTT

DISCOVER-AQ California Deployment P-3B Aircraft In Situ Meteorological and Navigational Data10.5067/ASDC/SUBORBITAL/DISCOVERAQ_California_MetNav_AircraftInSitu_P3B_Data_1

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

PlatformsP-3 Orion

FormatsICARTT

DISCOVER-AQ Texas Deployment P-3B Aircraft In Situ Meteorological and Navigational Data10.5067/ASDC/SUBORBITAL/DISCOVERAQ_Texas_MetNav_AircraftInSitu_P3B_Data_1

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

PlatformsP-3 Orion

FormatsICARTT

DISCOVER-AQ Colorado Deployment P-3B Aircraft In Situ Meteorological and Navigational Data10.5067/ASDC/SUBORBITAL/DISCOVERAQ_Colorado_MetNav_AircraftInSitu_P3B_Data_1

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

PlatformsP-3 Orion

FormatsICARTT

ASIA-AQ DC-8 In-Situ Meteorology and Navigation Data10.5067/SUBORBITAL/ASIA-AQ/DATA001/DC8/MetNav_AircraftInSitu_1

CampaignsAirborne and Satellite Investigation of Asian Air Quality

PlatformsDouglas DC-8

FormatsICARTT

ARCSIX P-3B In-Situ Meteorology and Navigation Data10.5067/SUBORBITAL/ARCSIX/DATA001/P3B/MetNav_AircraftInSitu_1

CampaignsArctic Radiation-Cloud-Aerosol-Surface Interaction EXperiment

PlatformsP-3 Orion

FormatsICARTT, KML

TRACE-P In Situ DC-8 Meteorology and Navigation Data10.5067/ASDC/SUBORBITAL/TRACE-P/MetNav_AircraftInSitu_DC8_Data_1

CampaignsTransport and Atmospheric Chemistry near the Equator

PlatformsDouglas DC-8

FormatsGTE

PEM Tropics B In-Situ DC-8 Meteorology and Navigation Data10.5067/ASDC/SUBORBITAL/PEM-Tropics-B/MetNav_AircraftInSitu_DC8_Data_1

CampaignsPacific Exploratory Mission

PlatformsDouglas DC-8

FormatsGTE

PEM Tropics A In-Situ DC-8 Meteorology and Navigation Data10.5067/ASDC/SUBORBITAL/PEM-Tropics-A/MetNav_AircraftInSitu_DC8_Data_1

CampaignsPacific Exploratory Mission

PlatformsDouglas DC-8

FormatsGTE

SARP 2018 Data10.5067/SUBORBITAL/SARP/DATA001/2018

CampaignsStudent Airborne Research Program

PlatformsDouglas DC-8

FormatsICARTT

SARP 2022 Data10.5067/SUBORBITAL/SARP/DATA001/2022

CampaignsStudent Airborne Research Program

PlatformsBalloon Launch Site, Douglas DC-8

FormatsICARTT, HDF

SARP 2024 Data10.5067/SUBORBITAL/SARP/DATA001/2024

CampaignsStudent Airborne Research Program

PlatformsBeechcraft B-200 King Air, P-3 Orion

FormatsICARTT, KML

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

CampaignsAtmospheric Tomography Mission

PlatformsDouglas DC-8

FormatsnetCDF

ATom: In Situ Atmospheric Water Vapor from the Diode Laser Hygrometer, Version 210.3334/ORNLDAAC/1937

CampaignsAtmospheric Tomography Mission

PlatformsDouglas DC-8

FormatsICARTT

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

CampaignsAtmospheric Tomography Mission

PlatformsDouglas DC-8

FormatsnetCDF

Diode Laser Hygrometer (DLH) IMPACTS10.5067/IMPACTS/DLH/DATA101

CampaignsInvestigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms

PlatformsP-3 Orion

FormatsASCII

ABoVE/ASCENDS: Active Sensing of CO2, CH4, and Water Vapor, Alaska and Canada, 201710.3334/ORNLDAAC/2050

CampaignsActive Sensing of CO2 Emissions over Nights, Days, and Seasons

PlatformsDouglas DC-8

FormatsICARTT

ABoVE/ASCENDS: Merged Atmospheric CO2, CH4, and Meteorological Data, 201710.3334/ORNLDAAC/2114

CampaignsActive Sensing of CO2 Emissions over Nights, Days, and Seasons

PlatformsDouglas DC-8

FormatsICARTT

DLHDiode Laser Hygrometer

Overview

Instrument Details

Instrument Operation

Data Products

DLH
Diode Laser Hygrometer