Ground-based Observing Ground-based Observing System for Climate Change System for Climate Change

Monitoring Monitoring

Tom AckermanTom Ackerman

Lecture II.6Lecture II.6

TopicsTopics

Why do we need ground-based Why do we need ground-based observations for climate and what observations for climate and what would we do with them?would we do with them?

What is measurement synergy all What is measurement synergy all about?about?

To be addedTo be added

Results from Monday discussionResults from Monday discussion

GCOS Position on Ground-based GCOS Position on Ground-based Observations for ClimateObservations for Climate

Primary tool is satellite(s)Primary tool is satellite(s) Surface and in situ observations only Surface and in situ observations only

needed forneeded for• Calibration and validationCalibration and validation• Measurement of parameters that cannot be Measurement of parameters that cannot be

measured by satellite (“biodiversity, measured by satellite (“biodiversity, groundwater, carbon sequestration, subsurface groundwater, carbon sequestration, subsurface ocean”)ocean”)

• Long time series for diagnosis of global change Long time series for diagnosis of global change (“surface temperature, precipitation and water (“surface temperature, precipitation and water resources, weather and other natural hazards, resources, weather and other natural hazards, … pollutants”)… pollutants”)

GCOS Position – Surface networksGCOS Position – Surface networks

GCOS surface network (GSN)GCOS surface network (GSN)• Measure in situ (surface) observations of Measure in situ (surface) observations of

surface temperature, humidity, wind speed and surface temperature, humidity, wind speed and directiondirection

• Mention “surface radiation (e. g., sunshine Mention “surface radiation (e. g., sunshine duration)”duration)”

• Approximately 1000 stations world wideApproximately 1000 stations world wide• Over ocean – volunteer ships, buoys (fixed and Over ocean – volunteer ships, buoys (fixed and

floating)floating)• Baseline Surface Radiation Network (BSRN) Baseline Surface Radiation Network (BSRN)

should be enhanced (currently a volunteer should be enhanced (currently a volunteer network of 39 stationsnetwork of 39 stations

BSRN LocationsBSRN Locations

GCOS Position – Surface networksGCOS Position – Surface networks

GCOS surface network (GSN)GCOS surface network (GSN) GCOS Upper Air Network (GUAN)GCOS Upper Air Network (GUAN)

• Radiosonde T, q, wind (~150 stations)Radiosonde T, q, wind (~150 stations)• Cloud properties from surface observerCloud properties from surface observer• Commercial aviation Commercial aviation

Global Atmospheric Watch (GAW)Global Atmospheric Watch (GAW)• CO2, CH4, O3, other GHGs, aerosolCO2, CH4, O3, other GHGs, aerosol• ~33 stations, some ship measurements~33 stations, some ship measurements

So, what’s wrong with this picture?So, what’s wrong with this picture?

A Minority Report and ProposalA Minority Report and Proposal

Acknowledgements to Acknowledgements to Jim Coakley (OSU) and Chuck Long (PNNL)Jim Coakley (OSU) and Chuck Long (PNNL)

Two underlying premisesTwo underlying premises

Understanding and addressing climate Understanding and addressing climate change will be a critical societal problem for change will be a critical societal problem for the next several decadesthe next several decades• The most important issues will be The most important issues will be water availabilitywater availability

and and energy production and useenergy production and use

Climate change is a global problem and must Climate change is a global problem and must be attacked with globally integrated models be attacked with globally integrated models and observationsand observations

Some Limitations of Satellite Some Limitations of Satellite ObservationsObservations

Surface fluxes of energy and Surface fluxes of energy and moisturemoisture

Properties of low-level clouds in Properties of low-level clouds in multi-layered systemsmulti-layered systems

Aerosols below and mixed with cloud Aerosols below and mixed with cloud layerslayers

Absorption of solar energy by Absorption of solar energy by aerosolsaerosols

More?More?

Role of ground-based observationsRole of ground-based observations

Continuous observations of cloud, aerosol and Continuous observations of cloud, aerosol and radiative properties at high temporal resolution radiative properties at high temporal resolution that facilitate the understanding of cloud and that facilitate the understanding of cloud and aerosol processes (aerosol processes (Improvement of atmospheric Improvement of atmospheric physicsphysics))

Alternative climatologies of radiation, cloud, and Alternative climatologies of radiation, cloud, and aerosol quantities crucial to climate change aerosol quantities crucial to climate change science (science (Model and satellite comparisonModel and satellite comparison))

Critical datasets to test the surface and cloud Critical datasets to test the surface and cloud properties retrieved from satellite observations properties retrieved from satellite observations ((EvaluationEvaluation))

A means for evaluating the performance of A means for evaluating the performance of satellite instruments over the lifetime of the satellite instruments over the lifetime of the satellite (satellite (CalibrationCalibration))

Level 1 stationsLevel 1 stations

Basic surface observation site – BSRN typeBasic surface observation site – BSRN type Measurements ofMeasurements of

• Surface energy fluxesSurface energy fluxes• Surface state variablesSurface state variables• Column aerosol propertiesColumn aerosol properties

Co-located with sonde sitesCo-located with sonde sites Order of 1000 to 2000 sites globallyOrder of 1000 to 2000 sites globally Site capital cost $75KSite capital cost $75K Site operational costs: $16K/yearSite operational costs: $16K/year

Level 2 SitesLevel 2 Sites

Includes Level 1 site instrumentsIncludes Level 1 site instruments Incorporates highly reliable remote Incorporates highly reliable remote

sensing instruments to measuresensing instruments to measure• Column water vaporColumn water vapor• Cloud base heightCloud base height• Aerosol backscatter profileAerosol backscatter profile• Cloud fraction and occurrenceCloud fraction and occurrence

Order of 100 to 200 sites globallyOrder of 100 to 200 sites globally Additional capital cost: $200KAdditional capital cost: $200K Additional site operational cost: $4KAdditional site operational cost: $4K

Level 3 SitesLevel 3 Sites Includes Level 2 site instrumentsIncludes Level 2 site instruments Like US ARM and European sitesLike US ARM and European sites High end remote sensing sites to measureHigh end remote sensing sites to measure

• Surface propertiesSurface properties• Vertical profiles of aerosol and cloud properties and Vertical profiles of aerosol and cloud properties and

thermodynamic variablesthermodynamic variables• Spectrally-resolved radiances and fluxesSpectrally-resolved radiances and fluxes

Focus on high spatial and temporal resolutionFocus on high spatial and temporal resolution Order of 10 to 20 sites globallyOrder of 10 to 20 sites globally Additional capital cost: $1.5MAdditional capital cost: $1.5M Additional site operational cost: UndeterminedAdditional site operational cost: Undetermined

CAP sitesProcess

Best obs possible

Augmented SitesClimatology

Measured cloud propertiesEnhanced meteorology

Basic surface radiation and meteorology sitesMonitoring

Sfc energy budget, aerosol OD, statistical cloud properties

IncreasingInstrument Complexity

Data volumeCost

Operator training

StrategyStrategy Integrate concept into climate observing system Integrate concept into climate observing system

plans such as GCOSplans such as GCOS Build on existing networksBuild on existing networks

• Sustained support for current sitesSustained support for current sites• Funding to expand observations to under-represented Funding to expand observations to under-represented

areas (oceans, southern hemisphere) => areas (oceans, southern hemisphere) => need much need much better geographical representationbetter geographical representation

Enable scienceEnable science• Shared and accessible data => archive!Shared and accessible data => archive!• Algorithm development and operational applicationAlgorithm development and operational application

From observations to science … From observations to science …

Three level plan implies a progression of Three level plan implies a progression of understanding and interpretationunderstanding and interpretation• More sophisticated measurements clarify what More sophisticated measurements clarify what

we can learn from less sophisticated we can learn from less sophisticated measurementsmeasurements

• Multiple measurements provide additional data Multiple measurements provide additional data that allow us to do more detailed comparisons that allow us to do more detailed comparisons with modelswith models

Top level sites are the key to making the Top level sites are the key to making the entire scheme work! entire scheme work!

The Atmospheric Radiation The Atmospheric Radiation Measurement ProgramMeasurement Program

Sites are prototypes of the Level 3 Sites are prototypes of the Level 3 sitessites

What have we learned from ARM? What have we learned from ARM?

Note: Sites in Europe (e. g., Cabauw, Lindenberg, Palaiseau, Chilbolton) are as well instrumented and scientifically useful as the ARM sites. ARM is a more operational program, so it offers the best model for us to consider here.

Atmospheric Radiation Measurement Atmospheric Radiation Measurement ProgramProgram

GoalGoal

Improve the treatment of cloud and radiation Improve the treatment of cloud and radiation physics in global climate models in order to physics in global climate models in order to improve the climate simulation capabilities of improve the climate simulation capabilities of these modelsthese models

Two fundamental science questionsTwo fundamental science questions

If we can specify the If we can specify the properties of a cloud field, properties of a cloud field, can we compute the can we compute the radiative fluxes?radiative fluxes?

Requires knowledge of cloud Requires knowledge of cloud properties (3D structure, water properties (3D structure, water path, phase, size, etc.)path, phase, size, etc.)

Two fundamental science questionsTwo fundamental science questions

If we can specify the large-If we can specify the large-scale atmospheric fields, scale atmospheric fields, can we predict the cloud can we predict the cloud field properties?field properties?

Requires 3D field of state Requires 3D field of state properties properties andand cloud field cloud field propertiesproperties

ARM Program ComponentsARM Program Components

Development of ground-based remote sensing Development of ground-based remote sensing facilitiesfacilities

Continuous data acquisition and archivalContinuous data acquisition and archival

Data analysisData analysis Physical modelingPhysical modeling Parameterization development and testingParameterization development and testing

Infrastructure

Science

ARM HistoryARM History Program initiated in 1990Program initiated in 1990

• initial science grantsinitial science grants

• Site planning and instrument selection Site planning and instrument selection

USA facility (SGP) data available since 1994USA facility (SGP) data available since 1994

Full instrumentation in 1996Full instrumentation in 1996 Tropical western Pacific site Tropical western Pacific site

• Manus 1996Manus 1996

• Nauru 1998Nauru 1998

• Darwin 2003Darwin 2003

North Slope of Alaska (Pt. Barrow) since 1998North Slope of Alaska (Pt. Barrow) since 1998 ARM Mobile Facility first deployment in 2005ARM Mobile Facility first deployment in 2005

Central Facility

Southern Great Plains Southern Great Plains

Southern Great Plains Central FacilitySouthern Great Plains Central Facility

North Slope of AlaskaNorth Slope of Alaska

North Slope of Alaska – Barrow facilityNorth Slope of Alaska – Barrow facility

Tropical Western PacificTropical Western Pacific

Darwin

Tropical Tropical Western Western

Pacific SitesPacific Sites

Nauru

Darwin

Manus, PNG

The ARM Mobile Facility at Pt. The ARM Mobile Facility at Pt. ReyesReyes

What have we learned in ARM about What have we learned in ARM about ……

Operating ground-based sitesOperating ground-based sites

Continuous measurementsContinuous measurements• Can be done but difficult in remote locationsCan be done but difficult in remote locations• Measurement synergy is key to science successMeasurement synergy is key to science success

Instrument improvement and developmentInstrument improvement and development• Interaction with science community is criticalInteraction with science community is critical

ExpensiveExpensive• But not when compared with science returnBut not when compared with science return

Data acquisition and archivingData acquisition and archiving

Science success depends on a good archiveScience success depends on a good archive Good => reliable, easy to use, responsiveGood => reliable, easy to use, responsive Best metric is Best metric is useruser satisfaction satisfaction Second best metric is data Second best metric is data outflowoutflow

Data analysis Data analysis

Data must be calibrated and quality-controlledData must be calibrated and quality-controlled Continuous dataContinuous data

• Multiple instrumentsMultiple instruments• Multiple sitesMultiple sites• Multiple seasons and yearsMultiple seasons and years

Scientists will find more things to do with the Scientists will find more things to do with the data than you ever imagineddata than you ever imagined

High-resolution atmospheric modelingHigh-resolution atmospheric modeling

Most profitable area of scientific investigationMost profitable area of scientific investigation• GEWEX Cloud System Studies (GCSS) linkGEWEX Cloud System Studies (GCSS) link• Weather forecasting centers (ECMWF, NCEP, etc.)Weather forecasting centers (ECMWF, NCEP, etc.)

Data used for Data used for • Model initializationModel initialization• Model evaluationModel evaluation• Model developmentModel development

Classification studiesClassification studies

Evaluating and improving climate Evaluating and improving climate modelsmodels

Most difficult problemMost difficult problem• Requires a lot of dataRequires a lot of data• Dependent on clever data analysis and understandingDependent on clever data analysis and understanding• Critical issues of spatial and temporal samplingCritical issues of spatial and temporal sampling

We are making significant progress!We are making significant progress!• Model evaluationModel evaluation• Cloud and convection parameterizationsCloud and convection parameterizations

(more about this later!)(more about this later!)

Retrievals, Synergy and RedundancyRetrievals, Synergy and Redundancy In the beginning, there was one measurement In the beginning, there was one measurement

and one retrieved propertyand one retrieved property Lidar backscatter => Cirrus optical depthLidar backscatter => Cirrus optical depth

Required closure assumptions!

Retrievals, Synergy and RedundancyRetrievals, Synergy and Redundancy

Then we added a Then we added a measurement of measurement of Window Window Radiance Radiance

Lidar + I(10 mic) Lidar + I(10 mic) => => and IWP and IWP

Synergy!

Retrievals, Synergy and RedundancyRetrievals, Synergy and Redundancy

Then we added Then we added an an InterferometerInterferometer

Lidar + I(Lidar + I() => ) => , IWP, Deff, IWP, Deff

Synergy!

Redundancy!

Retrievals, Synergy and RedundancyRetrievals, Synergy and Redundancy

Then we added a Then we added a mm radarmm radar

Radar + Lidar + I(Radar + Lidar + I() ) => multiple values => multiple values of of , IWP, Deff , IWP, Deff

Synergy!

Redundancy!

Choice!

Retrievals, Synergy and RedundancyRetrievals, Synergy and Redundancy

Multiple measurements allow us to Multiple measurements allow us to retrieve more pieces of informationretrieve more pieces of information

Observational redundancy allows us to Observational redundancy allows us to address issues of instrument noise address issues of instrument noise

Multiple measurements allow us to Multiple measurements allow us to perform complex retrievals that optimize perform complex retrievals that optimize information based on instrument information based on instrument operational characteristicsoperational characteristics

A priori information based on our A priori information based on our knowledge of atmospheric phenomena can knowledge of atmospheric phenomena can also be folded into the retrieval processalso be folded into the retrieval process