ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
The Atmospheric Radiation Measurement (ARM) Program:
An Overview
The Atmospheric Radiation Measurement (ARM) Program:
An Overview
Robert G. EllingsonDepartment of Meteorology
Florida State UniversityTallahassee, FL
Robert G. EllingsonDepartment of Meteorology
Florida State UniversityTallahassee, FL
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
OutlineOutline
• Where did we start?
• What have we done?
• Where are we going?
• Where did we start?
• What have we done?
• Where are we going?
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Where did we start?Where did we start?
1990: The single largest cause of variability in climate models is the treatment of clouds and their coupling to the earth radiation budget– Cess et al., JGR
– Our Changing Planet, USGCRP
=> the cloud parameterization problem
1990: The single largest cause of variability in climate models is the treatment of clouds and their coupling to the earth radiation budget– Cess et al., JGR
– Our Changing Planet, USGCRP
=> the cloud parameterization problem
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM GoalARM Goal
To improve the performance of General Circulation Models (GCMs) by:
• Improving the treatment of radiative transfer under clear sky, general
overcast, and broken cloud conditions
• Improving the parameterization of properties and formation of clouds
To improve the performance of General Circulation Models (GCMs) by:
• Improving the treatment of radiative transfer under clear sky, general
overcast, and broken cloud conditions
• Improving the parameterization of properties and formation of clouds
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM Questions
• If we can specify a cloud field, can we compute the radiative fluxes?
=> Requires knowledge of cloud properties
(3D structure, water path, phase, size,
etc.)
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Need atmospheric observations to
-- test hypothesis in process model studies
-- analyze for empirical relationships and statistical characteristics
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM Questions
• If we can specify a cloud field, can we compute the radiative fluxes?
=> Requires knowledge of cloud properties
(3D structure, water path, phase, size, etc.)
• If we can specify the large-scale atmospheric fields, can we predict the cloud field properties?
=> Requires 3D field of state properties and cloud
field properties
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Need data sets that describe the large scale environment in which clouds form
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM Program ComponentsARM Program Components
• Development of ground-based remote sensing facilities
• Continuous data acquisition and archival• Data analysis• Physical modeling• Parameterization development and testing
• Development of ground-based remote sensing facilities
• Continuous data acquisition and archival• Data analysis• Physical modeling• Parameterization development and testing
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
What have we done?What have we done?
• Sites
• Science
• Sites
• Science
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Location of Current ARM Sites
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Southern Great Plains Site
Central Facility
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Southern Great Plains Central FacilitySouthern Great Plains Central Facility
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
North Slope of Alaska SiteNorth Slope of Alaska Site
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
North Slope of Alaska SiteNorth Slope of Alaska Site
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Tropical Western Pacific SiteTropical Western Pacific Site
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Tropical Western Pacific SiteTropical Western Pacific Site
Manus Island
Nauru
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Instrumentation at SitesInstrumentation at Sites
• 35 GHz Radar (cloud properties)
• Lidar (pulsed laser; particle and thin cloud properties )
• Sky imagers (cloud cover)
• Broad-band and narrow-band radiometers (solar and infrared radiation)
• Microwave radiometer (water vapor and liquid water)
• Meteorology sensors (temp, humidity, winds)
• 35 GHz Radar (cloud properties)
• Lidar (pulsed laser; particle and thin cloud properties )
• Sky imagers (cloud cover)
• Broad-band and narrow-band radiometers (solar and infrared radiation)
• Microwave radiometer (water vapor and liquid water)
• Meteorology sensors (temp, humidity, winds)
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM Science -- Some Examples*ARM Science -- Some Examples*
• Instrument development and data analysis
• Radiation Studies• Model testing and development
* Lots of possible choices!
• Instrument development and data analysis
• Radiation Studies• Model testing and development
* Lots of possible choices!
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Total Sky Imager -- NauruTotal Sky Imager -- Nauru
99-07-13 1150 99-07-13 1351
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM Raman LidarARM Raman Lidar
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM Millimeter Cloud Radar (MMCR)ARM Millimeter Cloud Radar (MMCR)
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
35 GHz Radar Reflectivity (Arctic)35 GHz Radar Reflectivity (Arctic)
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Radar dataRadar data
ARM now has 4 radars in operation:• SGP – 4 years of data• TWP Nauru – 2.5 years• TWP Manus – 1+ years• NSA – 2 years
ARM now has 4 radars in operation:• SGP – 4 years of data• TWP Nauru – 2.5 years• TWP Manus – 1+ years• NSA – 2 years
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM Science -- Some Examples*ARM Science -- Some Examples*
• Instrument development and data analysis
• Radiation Studies• Model testing and development
• Instrument development and data analysis
• Radiation Studies• Model testing and development
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
The Radiation QuestionsThe Radiation Questions
Can we compute solar transmission and infrared emission accurately– in a clear atmosphere?
– in an atmosphere with an overcast, single-layer cloud?
– in an atmosphere with broken clouds and/or multiple cloud layers?
Can we compute solar transmission and infrared emission accurately– in a clear atmosphere?
– in an atmosphere with an overcast, single-layer cloud?
– in an atmosphere with broken clouds and/or multiple cloud layers?
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Clear AtmosphereClear Atmosphere
• Yes– Infrared irradiance to < 5 W/m2 (2%)
– Solar direct irradiance to < 0.5%
– Solar diffuse irradiance to < 10 W/m2
(if we account for diffuse radiometer offset)
• Remaining uncertainty probably due to absorption by trace gas species or aerosol
• Yes– Infrared irradiance to < 5 W/m2 (2%)
– Solar direct irradiance to < 0.5%
– Solar diffuse irradiance to < 10 W/m2
(if we account for diffuse radiometer offset)
• Remaining uncertainty probably due to absorption by trace gas species or aerosol
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Single Layer CloudSingle Layer Cloud
• Maybe (anomalous absorption problem)– Question is whether measured atmospheric
absorption in clouds exceeds calculated absorption
– Published articles show both
Measured = 1.5 * Calculated
Measured ~ Calculated
• Maybe (anomalous absorption problem)– Question is whether measured atmospheric
absorption in clouds exceeds calculated absorption
– Published articles show both
Measured = 1.5 * Calculated
Measured ~ Calculated
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Current ARM Role in the ProblemCurrent ARM Role in the Problem
• ARESE II Experiment (March, 2000)– Stratus cloud experiment at SGP site
– Instrument radiation airplane flying above cloud over central facility
– Remote sensing of cloud from ground
– Some in cloud sampling with second aircraft
• Data released to public after examination and evaluation by ARESE science team
• ARESE II Experiment (March, 2000)– Stratus cloud experiment at SGP site
– Instrument radiation airplane flying above cloud over central facility
– Remote sensing of cloud from ground
– Some in cloud sampling with second aircraft
• Data released to public after examination and evaluation by ARESE science team
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Results To DateResults To Date
• Analyzed 3 cloud days• Preliminary results show
measured = 1.1 – 1.15 * calculated• Experimental uncertainty
– In individual measurements: few %
– In net flux (difference): few % to 10 %
• Evaluation continues, group of papers to be submitted by end of summer
• Analyzed 3 cloud days• Preliminary results show
measured = 1.1 – 1.15 * calculated• Experimental uncertainty
– In individual measurements: few %
– In net flux (difference): few % to 10 %
• Evaluation continues, group of papers to be submitted by end of summer
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Broken Clouds Broken Clouds
• Don’t know• Work in progress
– Defining 3D cloud properties
– Developed 3D radiation codes for solar spectrum
– Comparison study of 3D codes
• Don’t know• Work in progress
– Defining 3D cloud properties
– Developed 3D radiation codes for solar spectrum
– Comparison study of 3D codes
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM Education Outreach ProgramARM Education Outreach Program
• ARM Program mandates an education outreach program for each CART site.
• Education outreach must be relevant to the needs of the local and regional communities.
• Content and management of the program has been determined by the CART Site Manager.
• Starting in FY2000, the Education Outreach Program is now integrated across all 3 sites.
• ARM Program mandates an education outreach program for each CART site.
• Education outreach must be relevant to the needs of the local and regional communities.
• Content and management of the program has been determined by the CART Site Manager.
• Starting in FY2000, the Education Outreach Program is now integrated across all 3 sites.
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Check out our Scavenger Hunt !!
http://www.arm.gov/docs/education/
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
NSA Classroom visits NSA Classroom visits
Classroom visits in Barrow
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Curriculum Workshops in the TropicsCurriculum Workshops in the Tropics
ARM scientists and regional collaborators present background materials. Teachers practice activities that demonstrate concepts for later use in their classrooms.
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
TWP Teacher ParticipationTWP Teacher Participation
Manus: “Atmospheric Pressure”
(Module 1, Book 1)
Manus: “Making Clouds”
(Module 2, Book 1)
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
TWP Teacher ParticipationTWP Teacher Participation
Manus: “When Land Ice Melts”
(Module 4, Book 1)
Port Moresby: “Plant Growth and Carbon Dioxide”
(Module 3, Book 2)
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
The educational outreach portion of the ARM Program seeks to provide schools with the materials necessary to use environmental data in the classroom.
ARM data is available online through these web pages.
http://outreach.ocs.ou.edu/arm
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
Is ARM Still Needed?Is ARM Still Needed?
• IPCC Report (2001) cites largest areas of uncertainty in climate change scenarios:– Cloud feedbacks
– Effect of changing particle loading on cloud properties
• Too much of what we have learned is not yet incorporated into climate models
• Climate models need to be evaluated quantitatively and ARM data are part of the necessary tools
• IPCC Report (2001) cites largest areas of uncertainty in climate change scenarios:– Cloud feedbacks
– Effect of changing particle loading on cloud properties
• Too much of what we have learned is not yet incorporated into climate models
• Climate models need to be evaluated quantitatively and ARM data are part of the necessary tools
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM FutureARM Future
• Continue to operate ground-based sites– 10 year time series
– Transition some sites to permanent facility
– Construct mobile facility
• Expand science activities in parameter-ization and model development– ARM Fellows at NCEP and ECMWF
– Promote model comparison studies
– Link to operational testing of climate models
• Continue to operate ground-based sites– 10 year time series
– Transition some sites to permanent facility
– Construct mobile facility
• Expand science activities in parameter-ization and model development– ARM Fellows at NCEP and ECMWF
– Promote model comparison studies
– Link to operational testing of climate models
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
ARM Future (2)ARM Future (2)
• Forge stronger links with national programs in hydrology, human health, and satellite remote sensing
– NASA Earth Observing System (EOS)
– DOE Tropospheric Aerosol Program (TAP)
• Forge links with international programs
– World Climate Research Programme (GEWEX)
– NASA Cloud Radar (Canada) and Lidar (France)
– European Space Agency
• Forge stronger links with national programs in hydrology, human health, and satellite remote sensing
– NASA Earth Observing System (EOS)
– DOE Tropospheric Aerosol Program (TAP)
• Forge links with international programs
– World Climate Research Programme (GEWEX)
– NASA Cloud Radar (Canada) and Lidar (France)
– European Space Agency
ARMARMAtmospheric Radiation MeasurementAtmospheric Radiation Measurement
In Conclusion, ARM …In Conclusion, ARM …
• Has a well defined mission in the climate research community
• Is a highly successful program in terms of its science impact
• Has important questions to address over the next 10 years
• Has a well defined mission in the climate research community
• Is a highly successful program in terms of its science impact
• Has important questions to address over the next 10 years
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