scispace - formally typeset

ReportDOI

ACRF Instrumentation Status: New, Current, and Future September 2006

01 Sep 2006-

AbstractThe purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development. New information is highlighted in blue text.

Summary (14 min read)

Jump to: [Introduction][1.1 90/150 GHz Microwave Radiometer][1.2.1 New Micro-Pulse Lidars][1.2.2 Upgrade Earlier Type-4 Micro-Pulse Lidars][1.3 Radar Wind Profiler][1.4 Infrared Sky Imager][1.5 Cimel Sun Photometer for Atmospheric Radiation Measurement Program Mobile Facility][1.6 Cloud Condensation Nuclei Counter for Southern Great Plains][1.7 Add Multi-Filter Radiometers to Cessna 206 (In-situ Aerosol Profiling aircraft)][1.8 Hot Plate Total Precipitation Sensor][1.9 Energy Balance Bowen Ratio Station at Darwin][2.1 Atmospherically Emitted Radiance Interferometer][2.1.1 Windows and Rapid-Sampling Upgrade][2.2 Aerosol Observing System][2.3 Balloon-Borne Sound System][2.3.1 Two-Per-Day Radiosonde Launches at Barrow][2.3.3 Make Atmospheric Radiation Measurement Program-Barrow Soundings Available to the Global Telecommunication System][2.4.1 Pyrgeometer Calibration Improvements][2.4.2 Radiometer Calibration Facility Data Acquisition System Replacement (deferred to][2.5 Carbon Dioxide Flux System][2.6 Carbon Monoxide System (CO)][2.7.1 Internet Data Transfer][2.9 Energy Balance Bowen Ratio Station][2.10 Eddy Correlation Station][2.10.1 Add Wetness Sensors][2.11 G-Band (183.3 GHz) Water Vapor Radiometer][2.12 Global Positioning System (SuomiNet)][2.13 In-situ Aerosol Profiling][2.13.1 Add Ozone Analyzer to In-situ Aerosol Profiles Suite][2.14 InfraRed Thermometer][2.15 Multi-Filter Rotating Shadowband Radiometer and Related Systems (MFR, GNDMFR, NIMFR)][2.15.1 Filter-Detectors][2.15.2 Multi-Filter Rotating Shadowband Radiometer Calibration and Data Processing Improvements][2.15.3 Data Logger Replacement][2.16.1 Processor Upgrades][2.16.2 Add Polarization at Barrow][2.16.3 Spare Traveling Wave Tubes][2.16.4 Millimeter Wave Cloud Radar Spectra Processing][2.16.5 Refurbish Millimeter Wave Cloud Radar Antennas][2.17 Micro-Pulse Lidar][2.17.1 Retrofit Spectra-Physics Lasers][2.18 MicroWave Radiometer][2.18.1 Unify MicroWave Radiometer Connectors][2.19 MicroWave Radiometer Profiller][2.21.1 Add Automatic Alignment System][2.22 Rotating Shadowband Spectrometer][2.23 Radar Wind Profiler – 915 MHz][2.23.1 Upgrade to Digital Receivers][2.24 Radar Wind Profiler – 50 MHz][2.25.1 Replace In-Ground Sensor Arrays][2.26 Shortwave Spectrometer (SWS)][2.27 Surface Meteorological Instrumentation (SMET, SMOS, SURTHREF, THWAPS, MET, ORG, PWS)][2.27.1 Develop Dynamic Rain Gauge Calibration Facility][2.27.2 Create Atmospheric Radiation Measurement Program Climate Research Facility Wind Sensor Repair Facility][2.27.3 Upgrade T/RH Probes and Wind Sensors for NSA Met Systems][2.28 Tandem Differential Mobility Analyzer][2.29 Total Sky Imager][2.30 Meteorological Tower Systems][2.32 W-band (95 GHz) Atmospheric Radiation Measurement Program Cloud Radar][2.32.2 Controller Modification][3.1 Atmospheric Radiation Measurement Program Volume-Imaging Array][3.3 Absolute Scanning Radiometer][3.4 High-Resolution Oxygen A-Band and Water-Band Spectrometer][3.5 Rotating Shadowband Spectrometer Overhaul][3.6 Narrow Field of View Radiometer for Atmospheric Radiation Measurement Program Mobile Facility][3.7 Add 1.6 :m Channel to Multi-Filter Rotating Shadowband Radiometer and Narrow Field of View][3.9 Future Microwave Radiometers][3.10 Modified Muti-Filter Rotating Shadowband Radiometer for Liquid Water Path][3.11 Infrared Thermometers for the Southern Great Plains Extended Facility Sites][4.1 Oxygen A-Band Spectrometer (FY 2005)][4.3 Instrumentation for Remotely Sensing Aerosol Optical Properties – Aerosol Phase Function (FY 2006)] and [4.5 Radiometer Radiosonde (FY 2006 National Science Foundation Solicitation)]

Introduction

  • The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status.
  • New information is highlighted in blue text.

1.1 90/150 GHz Microwave Radiometer

  • The need for greater sensitivity (and therefore higher frequency) microwave channels to more accurately measure liquid water paths in thin clouds than the current 23.8/31.4 GHz instruments permit has been extensively discussed.
  • Based on a technical evaluation of three proposals submitted for evaluation, Radiometer Physics, GmbH (RPG) (http://www.radiometer-physics.de) has been selected as the supplier with an option to purchase a second instrument (Engineering Change Order [ECO]-00491).
  • The second instrument will be deployed with the ARM Mobile Facility (AMF) to Germany in 2007.
  • Installation has been rescheduled for 18-20 October.

1.2.1 New Micro-Pulse Lidars

  • Combined with the upgrades described below, this will permit a new (or like new) MPL and an older type MPL to be deployed at each site (SGP-Central Facility [CF], NSA-Barrow, Tropical Western Pacific [TWP]-Darwin, TWP-Manus, TWP-Nauru, and AMF).
  • The new type-4b models will use a Photonics YAG laser with a shorter pulse width to achieve a minimum detection height of ~90 m rather than the 150-300 m detection height of the YLF laser in the earlier type-4b models.
  • The new systems will all have the ability to measure depolarization.
  • STATUS – Two of three upgraded systems have been delivered to SGP.

1.2.2 Upgrade Earlier Type-4 Micro-Pulse Lidars

  • Because the LiteCycles laser is no longer supported, the type-4 acquired in 2004 will be upgraded to a 4b, which involves engineering modifications in addition to replacing the laser; the 4b-YLF models acquired in 2005 will be upgraded to 4b-YAG by replacing the laser only.
  • These systems all have the ability to measure depolarization.
  • STATUS – Two of three upgraded systems have been delivered to SGP.
  • The laser for the remaining system exhibited low output power and has been returned to the laser manufacturer for examination/reworking.
  • Following acceptance testing, two of these MPLs will be sent to TWP (Manus and Nauru); the remaining system will serve as a spare.

1.3 Radar Wind Profiler

  • Rich Coulter, Argonne National Laboratory A 4-panel 1290 MHz RWP has been ordered from Vaisala for the 2007 AMF deployment in Germany, also known as Mentor.
  • An operating frequency of 1290 MHz was selected to match EU and other global frequency allocations for boundary layer radar profilers.
  • In July the FAA denied a request for a license to operate the new RWP at the SGP for testing prior to the AMF deployment to Germany in April 2007.

1.4 Infrared Sky Imager

  • Mentor: Vic Morris, Pacific Northwest National Laboratory An IR sky imager from Blue Sky Imaging (http://www.aas.org/career/bluesky.html) was deployed at SGP in September 2005 to provide nighttime cloud cover measurements (ECO-00429).
  • Problems with moisture infiltration of the imager necessitated its return to the manufacturer for repair/revision in October 2005.
  • The unit was returned to SGP in late June.
  • STATUS – The new heaters appear to prevent moisture accumulation inside the instrument.
  • The images look reasonable compared with the TSI images.

1.5 Cimel Sun Photometer for Atmospheric Radiation Measurement Program Mobile Facility

  • The Aerosol Working Group endorsed the deployment of a Cimel sun photometer with the AMF.
  • One of which is a spare that could be used for this purpose, Brent Holben (National Aeronautics and Space Administration [NASA] Aerosol Robotic 3 Network [AERONET] principal investigator) has indicated that he would prefer ARM continue to use the spare Cimel to ensure the uninterrupted operation of their three field units.
  • AERONET has agreed to support the new instrument (ECO-00560).
  • August 2006 – The AMF Cimel (station name: Niamey) is now operational.
  • Data may be obtained from the AERONET web page beginning 4 August.

1.6 Cloud Condensation Nuclei Counter for Southern Great Plains

  • John Ogren and Anne Jefferson, National Oceanic and Atmospheric Administration/Earth System Research Laboratory/Global Monitoring Division A CCN counter has been included in the AOS for the AMF, also known as Mentor.
  • A CCN counter for SGP is planned for FY2006.
  • (ECO-00565) STATUS – In September Anne Jefferson installed the CCN counter at SGP.

1.7 Add Multi-Filter Radiometers to Cessna 206 (In-situ Aerosol Profiling aircraft)

  • Currently, spectral albedo measurements are only possible at the SGP central facility using downward facing Multi-Filter Radiometers (MFR) on the 25-m level of the 60-m tower over a wheat field, and on a 10-m tower over the adjoining pasture.
  • By adding a MFR to the Cessna 206 used for the In-situ Aerosol Profile (IAP), routine measurements of surface spectral albedo could be acquired over a broader area around the SGP central facility (ECO-00584).
  • August 2006 – Pat Sheridan held a conference call with Joe Michalsky and MFRSR mentors Gary Hodges and John Schmelzer to choose a suitable location on the aircraft to mount the sensor head and to integrate the data acquisition system.
  • STATUS – Discussions continue regarding where on the aircraft to mount the sensor head.

1.8 Hot Plate Total Precipitation Sensor

  • It also offers the promise of handling under-catchment due to winds.
  • One Total Precipitation Sensor (TPS) was acquired for deployment at Barrow in November 2005.
  • The instrument will be deployed in close proximity to a double fence inter-comparison reference and Geonor gauge deployed by the National Oceanic and Atmospheric Administration (NOAA) Climate Reference Network 4 (CRN).
  • Data collection has been initiated; data ingest development is in progress.

1.9 Energy Balance Bowen Ratio Station at Darwin

  • The Cloud Parameterization and Modeling Working Group recommended deploying an Energy Balance Bowen Ratio (EBBR) station at the TWP-Darwin site in 2006 to provide measurements of the surface energy balance (ECO-00562).
  • This has been cancelled based on a discussion at the 2006 Science Team meeting between the CPMWG and the TWP Site Scientist Team.
  • An alternative would be to support Nigel Tapper and colleagues who have deployed EBBR stations and other instrumentation at more representative sites in the region around Darwin.

2.1 Atmospherically Emitted Radiance Interferometer

  • Jack Demirgian, Argonne National Laboratory Currently there were six AERIs operating, one out of service for repair, and one spare at the University of Wisconsin Space Science and Engineering Center (SSEC), also known as Mentor.
  • Three AERIs are currently still OS/2-based systems producing data every 8 minutes: SGP central facility (SGP-C1), Nauru (TWP-C2), and AMFNiamey.
  • The AERI at Burrow (NSA-C1), at the SGP central facility (SGP-E14), and at Darwin (TWPC3) are Windows XP-based and in 10-seconds rapid sampling mode.

2.1.1 Windows and Rapid-Sampling Upgrade

  • Migration of the AERI software from OS/2 Warp to Windows XP and related computer hardware modernization to enable rapid sampling of the IR spectrum at 10-s intervals was begun in FY 2004 (ECO00286).
  • In FY 2005, 2 AERI systems were upgraded and installed at NSA-Barrow and SGP-CF.
  • Due to the failure of the second Barrow system it will not be upgraded until after the other AERI systems have been upgraded.
  • The AERI deployed with the AMF will be upgraded following the completion of the Niamey deployment then redeployed with the ARMF to Germany.
  • STATUS – The upgraded electronics, Windows WP computer, and software were installed in the AERI at Darwin in September.

2.2 Aerosol Observing System

  • John Ogren and Anne Jefferson, National Oceanic and Atmospheric Administration/Earth System Research Laboratory/Global Monitoring Division AMF – Anne Jefferson traveled to Niamey in August to service the AOS there, also known as Mentor.
  • All AOS instruments are now working properly.
  • SGP – The condensation particle counter stopped measuring particle counts on August 11th.
  • The instrument was shipped back to the mentor for cleaning and was reinstalled in September.

2.3 Balloon-Borne Sound System

  • Barry Lesht, Argonne National Laboratory Over 90% of the soundings done at NSA, SGP, and TWP/C1 exceed the height and pressure targets of 20 km and 50 hPa, also known as Mentor.
  • Ascent rates were generally within acceptable range (4-6 m/s).
  • There is an inverse relationship between ascent rate and altitude at termination.
  • As a result, the NIM and TWP/C2 soundings, which generally had the highest ascent rates, tended to terminate earlier and at lower altitudes than the other ARM soundings.

2.3.1 Two-Per-Day Radiosonde Launches at Barrow

  • Unlike previous months, when over 91% of all ARM soundings terminated normally, the authors had only 81% terminate normally in August.
  • This change reflects possible problems at SGP, where 98% of the soundings done using the primary system terminated normally and only 18% of those done using the backup system terminated normally.
  • Experience at the other ARM sites was much better with normal termination values of about 98% at NSA, 95% at TWP/C2 , and 94% at Niamey.
  • The SGP digiCORA-III failed twice during the month.
  • The system was down again on 8/22, this time because of the failed power supply board.

2.3.3 Make Atmospheric Radiation Measurement Program-Barrow Soundings Available to the Global Telecommunication System

  • August 2006 – Barry has received a WMO station identifier (70270) for the ACRF Barrow site from NOAA/NWS.
  • Having a permanent station ID for Barrow will facilitate transmittal of Barrow soundings to the GTS.
  • Brian Ermold repaired the SGP GTS transmittal so that data messages are no longer incomplete.

2.4.1 Pyrgeometer Calibration Improvements

  • Tom Stoffel and Ibrahim Reda have initiated an investigation into the source of the bias in the ACRF pyrgeometer blackbody calibration system.
  • Once the source of the bias is determined and corrected a careful validation of the system and a comparison of pyrgreometers calibrated with this and other systems will be conducted (ECO-00559).
  • The source of the calibration bias appears to be due to a 1.5°-2.0°C temperature gradient in the blackbody that develops below -20°C when the viscosity of the silicone oil coolant becomes too great to provide proper mixing.
  • National Renewable Energy Laboratory (NREL) has redesigned and is testing the fluid dispersion manifolds surrounding the blackbody to reduce thermal gradients.
  • In March Joe Michalsky, Ells Dutton, and Ibrahim Reda exchanged groups of pyrgeometers recently calibrated by PMOD/WRC to confirm data analysis methods, and continued evaluating results from three PIRs with 3 dome thermistors, three PIRs with a single dome thermistor, and a CG4 in a round-robin involving NREL and NOAA blackbodies and outdoor characterizations.

2.4.2 Radiometer Calibration Facility Data Acquisition System Replacement (deferred to

  • FY 2007) The data acquisition system in the Radiometer Calibration Facility (RCF) used for annual Broadband Outdoor Radiometer Calibration activities is over ten years old and needs to be updated.
  • NREL has recently replaced their BORCAL data acquisition system using internal funds.
  • The SGP system should be a duplicate of the NREL system for software compatibility and performance assurance.

2.5 Carbon Dioxide Flux System

  • Marc Fischer, Lawrence Berkeley National Laboratory, also known as Mentor.
  • The Carbon Dioxide Flux System instruments at 4, 25, and 60 m on the SGP-CF tower are operating nominally.
  • In July, the soil sensors were re-installed following farm operations.
  • One heat flux plate was damaged by rodents and will be replaced.
  • A problem was also found with the thermometer on the net radiometer, which was sent to the vendor for service and calibration.

2.6 Carbon Monoxide System (CO)

  • Sébastien Biraud, Lawrence Berkeley National Laboratory, also known as Mentor.
  • Sébastien Biraud traveled to SGP Central Facility site (July 18-24, 2006) to perform instrument maintenance and calibration.

2.7.1 Internet Data Transfer

  • The transfer of CSPHOT data from the Cimel instrument to AERONET using geostationary operational environmental satellite or Meteosat will be replaced with an Internet data transfer to improve reliability of the transfer, to permit ACRF personnel to monitor the transfer, and to allow the raw data to be acquired, ingested, and archived for use by ARM Science Team members (ECO-00555).
  • STATUS – Internet data transfer was successfully tested with the new CSPHOT before if was sent to AERONET for calibration.
  • The other four ARM-owned CSPHOTs will require an upgrade to support Internet data transfer.
  • AERONET personnel will install the upgrades when the instruments are returned for annual calibration.

2.9 Energy Balance Bowen Ratio Station

  • David Cook, Argonne National Laboratory All EBBR stations are operating nominally, also known as Mentor.
  • Occasional problems with the automatic exchange mechanism and in-ground sensors are noted.
  • Observed biases between the EBBR net radiometer and Solar Infrared Station radiometer suite are attributed largely to poor longwave sensitivity for low sky temperatures in the EBBR net radiometer.
  • In July a grass fire due to lightning damaged the station at Earlsboro (E27); the AEM was replaced and the instrument was quickly returned to service.
  • Replacement probes are available from the EBBR manufacturer.

2.10 Eddy Correlation Station

  • David Cook, Argonne National Laboratory SGP – All 10 ECOR stations are operating nominally, also known as Mentor.
  • In late May the station at SGP/E1 was removed and shipped to Argonne for evaluation of the serial communication problems between the Infrared Gas Analyzer (IRGA) and the sonic anemometer.
  • Damaged serial port hardware (probably due to a lightning-induced electrical surge) was diagnosed.
  • Optical isolators will be added to all ECOR serial data cables to prevent a recurrence.
  • AMF – The CO2 concentration and flux data from the AMF ECOR are periodically affected by aircraft operations at the adjacent Niamey airport.

2.10.1 Add Wetness Sensors

  • Periods of dew, frost, and precipitation often cause data from the CO2/H2O sensor and sonic anemometer to be incorrect.
  • Adding a wetness indication would provide the data user with a more reliable source of information concerning this condition (ECO-00536).
  • 10 STATUS – Wetness sensors have been received.
  • One has been sent to the mentor for incorporation into a test ECOR system.

2.11 G-Band (183.3 GHz) Water Vapor Radiometer

  • In May the G-Band Water Vapor Radiometer (GVR) was returned to ProSensing for upgrades based on the evaluation of its first year of deployment.
  • These included improving the receiver stability, hardening the radiometer against radio-frequency interference from the nearby distant early warning Line radar, making the serial communication more robust, and eliminating unnecessary connectors in the data cables.
  • The GVR has been returned to Barrow and will be installed in August.

2.12 Global Positioning System (SuomiNet)

  • None (external data provided by SuomiNet/COSMIC) SGP – Telecommunications problems at LeRoy (E3) and El Reno (E19) affected data availability from these SuomiNet stations, also known as Mentor.
  • The temperature/relative humidity sensor associated with the Manus Island system failed in July 2005 but was not discovered until May 2006.
  • The sensor will be replaced on the next service visit to Manus Island.
  • Procedures for routinely examining the data from the SuomiNet systems were developed and implemented in response to these problems.
  • The spare ARM GPS meteorological system currently in use at Barrow will be connected to this receiver once the UAF met system is repaired and returned to Barrow, then the Atqasuk station will be incorporated into SuomiNet to provide precipitable water vapor data.

2.13 In-situ Aerosol Profiling

  • John Ogren and Betsy Andrews, National Oceanic and Atmospheric Administration/Earth System Research Laboratory/Global Monitoring Division, also known as Mentor.
  • In February FAA approval was obtained for the new equipment racks and IAP flights resumed over SGP with the new equipment on March 2, 2006.
  • In May the Lawrence Berkeley National Laboratory’s Continuous Carbon Analyzer was installed on the Cessna 206 and became operational.
  • It appears that water is condensing inside the high (85%) relative humidity nephelometer overnight if it is shut down with 85% RH air in it.

2.13.1 Add Ozone Analyzer to In-situ Aerosol Profiles Suite

  • This instrument is currently being used by GMD to measure vertical profiles of ozone 2-3 times per month at 8 sites in the U.S. on aircraft operated by the North American Carbon Project.
  • It is also included in the NOAA Airborne Aerosol Observatory Cessna 206 that has recently begun obtaining aerosol and trace gas profiles 2-3 times weekly in east-central Illinois.

2.14 InfraRed Thermometer

  • Vic Morris, Pacific Northwest National Laboratory InfraRed Thermometers (IRTs) have been deployed at 12 SGP extended facilities (ECO-345), operating at 5 Hz sampling rate, also known as Mentor.
  • IRTs are also part of the SKYRAD and GNDRAD systems at TWP, NSA, and AMF.
  • The IRTs are operating nominally at all sites.
  • IRTs at SGP and TWP report higher sky temperatures than the AERI over the 10-μm passband of the IRT.

2.15.1 Filter-Detectors

  • ACRF has ~50 multi-filter radiometers deployed in a variety of configurations including the MFRSR, the downward-facing MFR, and the NIMFR.
  • The 6 narrow band (10 nm) filter-detectors in almost all of these sensors have degraded over time and are in urgent need of replacement.
  • Perkin-Elmer is producing custom-designed and custom-built filter-detector assemblies to meet ACRF specifications.
  • STATUS – 39 complete sets of filter-detectors were delivered in August and September with additional filter-detectors at most wavelengths.
  • John Schmelzer has begun using these to repair failed sensor heads.

2.15.2 Multi-Filter Rotating Shadowband Radiometer Calibration and Data Processing Improvements

  • Problems with the calibration and data processing of the MFRSRs were revealed during the ALIVE campaign (ECO-00571).
  • Joe Michalsky convened a meeting at Pacific Northwest National Laboratory during the last week of January to discuss the calibration issues and develop a plan to address them.
  • New calibration processing will be implemented based on the consensus procedures developed during the meeting.
  • Collection and ingest development are proceeding but have been delayed by the need to accommodate both the current proprietary data loggers and the new Campbell Scientific data loggers.
  • 13 STATUS – Nighttime measurements were implemented on the MFRSR at the SGP central facility in late July.

2.15.3 Data Logger Replacement

  • The proprietary data loggers supplied with the MFRSRs and related instruments are to be replaced with Campbell Scientific CR1000 data loggers.
  • This will permit them to be more easily maintained.
  • It will also permit modifications to the operation of the instruments and data acquisition to be easily implemented (ECO-00350).
  • The data logger program and output file format are being finalized.
  • STATUS – In 2005, 27 new data loggers were purchased for this replacement.

2.16.1 Processor Upgrades

  • The MMCRs at SGP-central facility and NSA-Barrow have been upgraded with the (now obsolete) C40 digital signal processor.
  • The installations at Manus and Nauru will be done after TWP-ICE.
  • July 2006 – Kevin Widener and Rex Pearson installed the new processor at Manus in June.
  • STATUS – Based on recent discussions, the spare PIRAQ-III processor will be installed in the MMCR at NSA .
  • Because the PIRAQ does not support polarization, the installation of the orthomode transducer at Barrow (see below) is on hold until the next processor upgrade.

2.16.2 Add Polarization at Barrow

  • Modifications to the PIRAQ-III processor will be necessary to support the polarization capability.
  • Polarization will be added during the summer of 2006 using the C40 processor.
  • The modifications to the PIRAQ processor will be completed prior to the upgrade of the SGP system, and then installed at Barrow later in 2006 (ECO-00552).
  • STATUS – The orthomode transducer has been received.
  • Because the PIRAQ processor does not support polarization, the installation of the orthomode transducer at Barrow is on hold until the next processor upgrade.

2.16.3 Spare Traveling Wave Tubes

  • New traveling wave tubes (TWT) will be ordered to replace the TWTs originally delivered with the MMCRs, which are well beyond their rated lifetime and are beginning to fail (ECO-00425).
  • STATUS – The first TWT has been delivered to SGP, incorporated into a TWTA, and sent to Nauru to repair the MMCR there.

2.16.4 Millimeter Wave Cloud Radar Spectra Processing

  • Spectra files produced by the upgraded MMCRs (C40 or PIRAQ-III processors) range from 8 to 15 Gigabytes per day.
  • Algorithms for eliminating clear-sky periods and compressing the files need to be developed and implemented locally (ECO-00391).
  • 15 STATUS – The algorithms have been developed and tested.
  • Karen Johnson is developing a test plan to validate each installation before data are irretrievably discarded.
  • Hardware has been received at SGP for the first installation.

2.16.5 Refurbish Millimeter Wave Cloud Radar Antennas

  • Beginning in 2007, over a three-year period the MMCR antennas will be refurbished and characterized on an antenna range (ECO-00551).
  • This antenna will be swapped for each antenna that is removed from service to be refurbished so that the radar is not out of service for an extended period.

2.17 Micro-Pulse Lidar

  • Albert Mendoza, Pacific Northwest National Laboratory, also known as Mentor.
  • All MPL systems are working well with the exception of the system at Nauru.
  • The system is currently double pulsing: a condition where the laser produces two pulses per trigger instead of one, which can be identified by an artifact in the backscatter data at 0.25 km.
  • The energy monitor of the AMF MPL often detects electronic noise during the nighttime.
  • This is not affecting the backscatter measurements.

2.17.1 Retrofit Spectra-Physics Lasers

  • The type-1 and type-2 units use Spectra-Physics lasers that are no longer supported (except for the AMF unit, which uses a LiteCycles laser that is no longer supported).
  • ARM has one spare Spectra-Physics laser head.
  • Four old Spectra-Physics laser supplies have been retrofitted by Sigma Space to use Coherent F-System laser diode modules and two remain to be retrofitted (ECO-00362).
  • Double pulsing of the lasers retrofitted with Coherent supplies has been occasionally observed in several MPL systems in the field.
  • The type-1 MPL at SGP has been removed from service and its laser diode supply sent to Sigma Space Corp. for upgrade.

2.18 MicroWave Radiometer

  • Maria Cadeddu, Argonne National Laboratory AMF – Fewer RFI spikes were observed in the MWR data this month, also known as Mentor.
  • The sun was observed in the field of view around solar moon.
  • The manufacturer discovered mechanical damage due to being dropped.
  • The instrument will be sent to SGP for comparison with other MWRs to determine whether significant damage was sustained.
  • SGP/B5 – Instrument was returned to the manufacturer to diagnose/repair thermal instability problem.

2.18.1 Unify MicroWave Radiometer Connectors

  • Accordingly, the Impulse connectors are being replaced with the standard connectors used on all other MWRs.
  • The damaged MWR has been repaired, its connectors replaced, and shipped to the manufacturer for connector replacement.
  • After the connectors are replaced the MWR will then be swapped with the unit at Manus.
  • STATUS – SGP technicians have built new cables with the standard connectors to replace the cables with the Impulse connectors at TWP sites.

2.19 MicroWave Radiometer Profiller

  • Maria Cadeddu, Argonne National Laboratory NSA – In September NSA Site Operations technicians successfully completed a liquid nitrogen calibration of the MWRP, also known as Mentor.
  • AMF – RFI at causes frequent spikes in the MWRP data.
  • The IRT on the MWRP is biased high relative to the SKYRAD IRT by 5-7°C.

2.21.1 Add Automatic Alignment System

  • Due to small thermal gradients in the laser and the lidar enclosure, the alignment of laser beam in the detectors’ field-of-view (FOV) changes with time, which can affect the data quality, sometimes substantially.
  • To address this operationally, the laser beam is swept through the detectors’.
  • FOV using a pico-motor controlled steering mirror to find the optimal location.
  • Licel has recently developed a new product that permits the alignment of the lidar to be actively maintained (ECO-00586).
  • Installation is planned for October or November 2006.

2.22 Rotating Shadowband Spectrometer

  • Peter Kiedron, State University of New York at Albany The Rotating Shadowband Spectrometer (RSS) is operating nominally, also known as Mentor.
  • Automatic processing of calibration data is under development by Peter Kiedron and Jim Schlemmer.

2.23 Radar Wind Profiler – 915 MHz

  • Rich Coulter, Argonne National Laboratory SGP – Currently, the systems at Beaumont (I1) and Medicine Lodge (I2) are operating nominally, though the RASS data at Medicine Lodge are “reflected” at large range gates, also known as Mentor.
  • The phase shifter at the central facility was replaced in February and the interface power supply was repaired.
  • The SGP/C1 (central facility) and SGP/I3 systems are out of service pending the digital receiver upgrades.
  • Maybe the upgraded hardware, LAPXM software, and new computer will help resolve this problem.

2.23.1 Upgrade to Digital Receivers

  • The four 915 MHz RWPs at the SGP are now 9-13 years old and are exhibiting increasingly frequent, strange, and expensive-to-repair failures.
  • This may pose problems for CLASIC, scheduled in 2007.
  • Due 18 to the age of these systems, parts are increasingly difficult to obtain (Vaisala no longer has exact replacements for some items; the available parts must be modified for use in their systems).
  • The systems at SGP/CF and SGP/I3 will be upgraded first, prior to CLASIC.
  • When implemented, this will alleviate the data collection problem associated with the large, growing daily data file that the collection procedure must presently handle and which creates occasional gaps in the spectral data files.

2.24 Radar Wind Profiler – 50 MHz

  • In January the 50 MHz RWP at the SGP ceased transmitting.
  • The transmitter was returned to ATRAD in Australia for diagnosis and repair.
  • After reinstalling the transmitter the output power was still zero.
  • Vaisala has loaned SGP test equipment to help diagnose the problem.

2.25.1 Replace In-Ground Sensor Arrays

  • The in-ground sensors for the SWATS deployed at all 22 SGP Extended Facilities (EFs) are arranged in two redundant vertical arrays so that if/when a sensor fails, there is a redundant sensor at the same level.
  • These sensors cannot be replaced without disturbing the soil and invalidating the measurements at all levels.
  • To address this problem, new redundant sensor arrays will be installed at the SGP EF sites.
  • These will be installed in a phased manner: 5 sites per year over the next 4 years beginning in 2005 with the sites having multiple failed sensors given highest priority.
  • STATUS – Don Bond installed replacement sensor arrays at the first two sites in late March.

2.26 Shortwave Spectrometer (SWS)

  • This instrument replaces the ASD spectrometer that was removed from service in 2003 after repeated hardware problems.
  • A LabSphere integrating sphere has been purchased to permit frequent calibrations to be performed at SGP (ECO-00428).
  • The SWS was deployed at the SGP in April.
  • The data are available from the ARM Archive.

2.27 Surface Meteorological Instrumentation (SMET, SMOS, SURTHREF, THWAPS, MET, ORG, PWS)

  • Mike Ritsche, Argonne National Laboratory SGP (Surface Meteorological Observing Station [SMOS]) – New Vaisala temperature/relative humidity probes ordered (15) to replace old probes no longer supported by Vaisala (EWO-11056), also known as Mentor.
  • TWP (SMET, ORG) – Lower wind sensor at Manus indicates low, may have a bad bearing.
  • ORG at Darwin reports 0.1 mm/hr constantly.
  • AMF (MET, ORG) – In May the ORG was not reporting rainfall and was replaced.

2.27.1 Develop Dynamic Rain Gauge Calibration Facility

  • The tipping bucket rain gauges at the 15 SGP/EF sites with SMOS are currently calibrated using only a “static” calibration: a measured volume of water is poured into the gauge and the number of bucket tips is checked to ensure they correspond.
  • In reality, as the rain rate increases and the bucket tips more frequently some rain is not collected.
  • The purpose of the dynamic calibration is to determine the correction factor as a function of rain rate to account for this behavior (ECO-00495).
  • August 2006 – All necessary components have been received.
  • The University of Iowa has delivered the software they developed.

2.27.2 Create Atmospheric Radiation Measurement Program Climate Research Facility Wind Sensor Repair Facility

  • Rather than return ACRF wind sensors to the manufacturer for repair, it is cost effective and far quicker to perform the repairs and calibrations on-site.
  • Repair facilities will be established at the SGP central facility and the TWP Darwin site (ECO-00561).
  • August 2006 – All necessary components have been received.
  • Testing and repair procedures have been prepared and distributed to the SGP and TWP Site Operations Teams.

2.27.3 Upgrade T/RH Probes and Wind Sensors for NSA Met Systems

  • Ice develops on the wind vanes, cup anemoneters, and aspirator inlets for the temperature and relative humidity sensors, which clog and affect the data quality.
  • To alleviate these problems the mentor has proposed to replace the wind speed and direction sensors at NSA (both Barrow and Atqasuk) with sonic anemometers, and to replace the temperature and relative humidity probes with new, heated probes designed to operate in cold environments (ECO-00595).
  • STATUS – Awaiting prioritization and 2007 funding.

2.28 Tandem Differential Mobility Analyzer

  • Don Collins, Texas A&M University Data from the Tandem Differential Mobility Analyzer (TDMA) are currently acquired and processed by Don Collins, also known as Mentor.
  • Processed data are then delivered to ACRF on a monthly basis and stored in the IOP area of the Archive as “beta-data.”.
  • An ingest is being developed to produce netcdf files for inclusion in the main Archive (ECO-587).

2.29 Total Sky Imager

  • Vic Morris, Pacific Northwest National Laboratory SGP – Operating nominally, also known as Mentor.
  • Birds occasionally perch on system, affecting the imagery.
  • TWP – In mid-May the TSI controller board at Darwin failed.
  • In July the spare was installed, wiring differences were corrected locally, and the system was returned to service in early August.
  • AMF – Sky cover fraction is biased high due to high atmospheric aerosol loading.

2.30 Meteorological Tower Systems

  • David Cook, Argonne National Laboratory 60-m tower at SGP C1 (central facility) – nominal operation, also known as Mentor.
  • 40-m tower at NSA C1 – problems due to ice formation on temperature/humidity sensors and on the wind direction vanes continue.
  • Replacement of these sensors with sonicanemometers is being considered (ECO-00595).

2.32 W-band (95 GHz) Atmospheric Radiation Measurement Program Cloud Radar

  • Kevin Widener, Pacific Northwest National Laboratory, also known as Mentor.
  • In March the AMF W-band ARM Cloud Radar (WACR) was successfully deployed at Niamey.
  • In April the SGP WACR was returned to service.
  • In May the pulse repetition frequency at Niamey was changed from 10 kHz to 8333.
  • This also decreases the maximum unambiguous Doppler velocity from 8 m/s to 6.6 m/s. Both AMF and SGP WACRs provided 100% uptime during August.

2.32.2 Controller Modification

  • To permit using a corner reflector for calibration, the WACR at SGP will be returned to ProSensing in September for controller firmware modification and RF switch characterization (ECO-00585).
  • A new, larger corner reflector will also be needed.
  • STATUS – In September the SGP WACR was removed and sent to ProSensing for modification.

3.1 Atmospheric Radiation Measurement Program Volume-Imaging Array

  • The ARM Volume-Imaging Array (AVA) is a proposed radar system to be deployed at the ARM SGP site to address the ARM program’s need of mapping 3D cloud and precipitation structures at short to medium ranges (i.e., 20-75 km).
  • Principal elements of the AVA proposal prepared by Pavlos Kolias include: Three networked scanning radars arranged in a triangle with 20-30 km legs: one operating at 35 GHz (same 8.6-mm wavelength as the MMCR) and capable of scanning the vertical region probed by the current MMCR, and two radars operating at 9.4 GHz (3.2-cm wavelength, so-called “X-band”).
  • Development of a useful 3D cloud Value Added Product (VAP) similar to the existing ARSCL but on a regular 3D grid.
  • STATUS – Cost estimates have been prepared for site preparation, installation, and operation support.
  • This proposal will be extensively discussed during the upcoming Science Work Group meetings.

3.3 Absolute Scanning Radiometer

  • To provide an absolute IR flux reference, which could be used to calibrate the Eppley PIRs, Ells Dutton has suggested that ARM develop an Absolute Scanning Radiometer (ASR).
  • This instrument would be functionally equivalent to an ASR developed by Rolf Philipona for the WMO.
  • As such it would participate in WMO inter-comparisons at Davos, Switzerland every five years.
  • Ells Dutton, Tom Stoffel, and Joe Michalsky are planning to develop a specification so that ACRF may send out a request for proposals to identify interest and cost for such an instrument.

3.4 High-Resolution Oxygen A-Band and Water-Band Spectrometer

  • Qilong Min has submitted a proposal to build an A-band spectrometer for ARM following his presentation to the Cloud Properties working group in October 2004 on this topic.
  • The 3-year proposal and budget were sent out for technical reviews.
  • The technical reviews, along with the proposal and budget, were then provided to the STEC.
  • The STEC directed Qilong to present his plan and budget to the Cloud Properties working group at their November 2005 meeting for prioritization.
  • Qilong presented a revised work plan (water-band/cloud phase components removed) and has submitted a revised budget.

3.5 Rotating Shadowband Spectrometer Overhaul

  • Peter Kiedron has demonstrated that the RSS built by Yankee Environmental System is capable of providing valuable measurements of direct, diffuse, and global spectral irradiance.
  • Peter has also identified problems with the RSS that affect the stability of its calibration and the linearity of its response.
  • Peter has recommended that the RSS be removed from service and sent to him at SUNY-Albany for a complete overhaul.

3.6 Narrow Field of View Radiometer for Atmospheric Radiation Measurement Program Mobile Facility

  • The 2-channel Narrow Field of View (NFOV) that was deployed with the AMF at Pt. Reyes has been redeployed at SGP.
  • A second 2-ch NFOV has been suggested for the AMF, although not for the Niger deployment.
  • Science Team members (Alexander Marshak and others) have decided that this is no longer necessary.
  • Due to the deployment of the new SWS at SGP, the 2-channel NFOV at SGP can be deployed with the AMF in 2007.

3.7 Add 1.6 :m Channel to Multi-Filter Rotating Shadowband Radiometer and Narrow Field of View

  • Alexander Marshak has recommended that ARM support the development of a NFOV radiometer at 1.6 µm to permit the retrieval of droplet size distribution.
  • Andy Lacis and colleagues have suggested a 1.6 µm channel be substituted for the unfiltered channel in the MFRSR.
  • A cursory examination of Perkin-Elmer’s web pages reveals Indium-Galium-Arsinide detectors are available that operate in this spectral region.
  • July 2006 – Two InGaAs detectors and two 1.6 µm filters have been purchased to determine the feasibility of implementing them in the MFRSR and/or NFOV.
  • In the MFRSR this filter-detector would replace the unfiltered channel.

3.9 Future Microwave Radiometers

  • The 2-channel MWRs range between 6-13 years old.
  • They are no longer being manufactured; Radiometrics has replaced them with an instrument that sequentially tunes to 5 frequencies in the 22-30 GHz range.
  • It is useful to begin considering replacements for these instruments.
  • RPG offers a comparably priced 3-channel radiometer (23.8, 31.4, 90.0 GHz) that could also be considered because it increases the sensitivity to thin liquid water clouds.
  • It is also desirable to acquire a final, “production” version of the 183 GHz microwave radiometer developed by ProSensing under a U.S. Department of Energy (DOE) SBIR Phase II award and deployed at Barrow since April 2005.

3.10 Modified Muti-Filter Rotating Shadowband Radiometer for Liquid Water Path

  • Qilong Min has proposed to modify the existing MFRSRs to permit him to retrieve liquid water path.
  • Software modifications would be required to position the shadow band at several additional angles near the solar disk; modifications to the shadow band would be needed to either narrow it or increase its distance from the diffuser.
  • A narrower diffuser (and modification to the sensor head) and an improved stepper motor and motor controller have also been proposed.
  • A first phase might utilize a Rotating Shadowband Radiometer loaned to Min from Brookhaven National Laboratory.

3.11 Infrared Thermometers for the Southern Great Plains Extended Facility Sites

  • Some of these have been deployed with the AMF.
  • The DOE SBIR web page is at http://www.er.doe.gov/sbir/.

4.1 Oxygen A-Band Spectrometer (FY 2005)

  • Based on recommendations from the 2004 ARM Science Team meeting breakout session on photon path length measurements, a subtopic requesting the development of an A-band spectrometer was included under the Atmospheric Technology.
  • In May 2005 Dr. Fedor Dimov of Physical Optics Corporation was awarded a Phase I grant for A-band spectrometer development.
  • The Phase II proposal by Kevin Yu and Fedor Dimov was not selected for funding.
  • 2 Eye-Safe Ultraviolet Backscatter Lidar for Detection of Sub-visual Cirrus (FY 2006) Based on recommendations from the 2004 Cloud Properties working group meeting, this subtopic was substituted for the A-band spectrometer subtopic.
  • Phase I funding was awarded to Aculight Corporation: “Eye-Safe ultraviolet Backscatter Lidar for Detection of SubVisual Cirrus” and to Physical Sciences, Inc.: “Field-Worthy ultraviolet Backscatter Lidar for Cirrus Studies.”.

4.3 Instrumentation for Remotely Sensing Aerosol Optical Properties – Aerosol Phase Function (FY 2006)

  • Based on recommendations from the Aerosol working group, this subtopic was added to the aerosol measurements subtopic.
  • Phase I funding was awarded to Aerodyne Research, Inc.: “CAPS-Based Particle Single Scattering Albedo Monitor.”.

4.5 Radiometer Radiosonde (FY 2006 National Science Foundation Solicitation)

  • The objective is to obtain a radiosonde with an onboard radiometer suitable for accounting for the radiative heating of the temperature sensor in the upper atmosphere.
  • The BBHRP focus group provided their requirements to Matt.
  • Global Aerospace representatives have been invited at attend the ARM Radiative Heating Profile Workshop being organized by Warren Wiscombe. 4.6 In-situ Measurement of Cloud Properties with Large Sample Volumes (FY 2007) Warren Wiscombe contributed the following sub-topic and will be the technical contact.
  • These effects, particularly how clouds respond to climate change (the so-called “cloud feedback” problem), are large yet poorly understood from both a measurement and modeling point of view (cf. Stephens 2005).
  • Currently, there is a huge gap in spatial scale between in-situ measurements of cloud properties, typically from aircraft and balloons whose instruments have sample volumes on the order of cubic centimeters, and remote sensing retrievals of cloud properties, which have sample volumes ranging from tens of cubic meters (radar and lidar) to thousands of cubic meters .

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Content maybe subject to copyright    Report

DOE/SC-ARM/P-06-011.3
ACRF Instrumentation Status:
New, Current, and Future
September 2006
James Liljegren
ACRF Instrument Team Coordinator
Work supported by the U.S. Department of Energy,
Office of Science, Office of Biological and Environmental Research

Summary
The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation
Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections:
(1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress
on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research
instrument development. New information is highlighted in blue text.

September 2006, DOE/SC-ARM/P-06-011.3
iii
Contents
1
New Instrumentation........................................................................................................................... 1
1.1 90/150 GHz Microwave Radiometer......................................................................................... 1
1.2 Micro-Pulse Lidar...................................................................................................................... 1
1.2.1 New Micro-Pulse Lidars ..............................................................................................1
1.2.2 Upgrade Earlier Type-4 Micro-Pulse Lidars................................................................2
1.3 Radar Wind Profiler .................................................................................................................. 2
1.4 Infrared Sky Imager................................................................................................................... 2
1.5 Cimel Sun Photometer for Atmospheric Radiation Measurement Program Mobile Facility.... 2
1.6 Cloud Condensation Nuclei Counter for Southern Great Plains ............................................... 3
1.7 Add Multi-Filter Radiometers to Cessna 206............................................................................ 3
1.8 Hot Plate Total Precipitation Sensor ......................................................................................... 3
1.9 Energy Balance Bowen Ratio Station at Darwin ...................................................................... 4
1.10 DigiCORA-III for Manus, Nauru.............................................................................................. 4
2 Existing Instrumentation ..................................................................................................................... 5
2.1 Atmospherically Emitted Radiance Interferometer................................................................... 5
2.1.1 Windows and Rapid-Sampling Upgrade...................................................................... 5
2.2 Aerosol Observing System........................................................................................................ 5
2.2.1 Reconfigure Southern Great Plains Aerosol Observing System .................................. 6
2.3 Balloon-Borne Sound System ................................................................................................... 6
2.3.1 Two-Per-Day Radiosonde Launches at Barrow ...........................................................6
2.3.2 RS92 Radiosondes at Darwin....................................................................................... 6
2.3.3 Make Atmospheric Radiation Measurement Program-Barrow Soundings
Available to the Global Telecommunication System...................................................
6
2.4 Broadband Radiometers ............................................................................................................ 7
2.4.1 Pyrgeometer Calibration Improvements ......................................................................7
2.4.2 Radiometer Calibration Facility Data Acquisition System Replacement ....................7
2.5 Carbon Dioxide Flux System .................................................................................................... 7
2.6 Carbon Monoxide System ......................................................................................................... 8
2.7 Cimel Sun Photometer............................................................................................................... 8
2.7.1 Internet Data Transfer ..................................................................................................8
2.8 Disdrometer............................................................................................................................... 8
2.9 Energy Balance Bowen Ratio Station ....................................................................................... 9
2.10 Eddy Correlation Station ........................................................................................................... 9
2.10.1 Add Wetness Sensors ...................................................................................................9
2.11 G-Band Water Vapor Radiometer........................................................................................... 10
2.12 Global Positioning System ...................................................................................................... 10
2.13 In-situ Aerosol Profiling.......................................................................................................... 11
2.13.1 Add Ozone Analyzer to In-situ Aerosol Profiles Suite .............................................. 11
2.14 InfraRed Thermometer ............................................................................................................ 11
2.15 Multi-Filter Rotating Shadowband Radiometer and Related Systems.................................... 12
2.15.1 Filter-Detectors........................................................................................................... 12
2.15.2 Multi-Filter Rotating Shadowband Radiometer Calibration and Data Processing
Improvements.............................................................................................................
12

September 2006, DOE/SC-ARM/P-06-011.3
iv
2.15.3
Data Logger Replacement ..........................................................................................13
2.16 Millimeter Cloud Radar........................................................................................................... 13
2.16.1 Processor Upgrades .................................................................................................... 14
2.16.2 Add Polarization at Barrow........................................................................................14
2.16.3 Spare Traveling Wave Tubes ..................................................................................... 14
2.16.4 Millimeter Wave Cloud Radar Spectra Processing ....................................................14
2.16.5 Refurbish Millimeter Wave Cloud Radar Antennas ..................................................15
2.16.6 Radome or Radome Dryer.......................................................................................... 15
2.17 Micro-Pulse Lidar.................................................................................................................... 15
2.17.1 Retrofit Spectra-Physics Lasers.................................................................................. 15
2.18 MicroWave Radiometer .......................................................................................................... 16
2.18.1 Unify MicroWave Radiometer Connectors................................................................ 16
2.19 MicroWave Radiometer Profiller............................................................................................ 16
2.20 Precision Gas System .............................................................................................................. 16
2.21 Raman Lidar............................................................................................................................ 17
2.21.1 Add Automatic Alignment System ............................................................................ 17
2.22 Rotating Shadowband Spectrometer ....................................................................................... 17
2.23 Radar Wind Profiler – 915 MHz ............................................................................................. 17
2.23.1 Upgrade to Digital Receivers ..................................................................................... 17
2.24 Radar Wind Profiler – 50 MHz ............................................................................................... 18
2.25 Soil Water and Temperature System....................................................................................... 18
2.25.1 Replace In-Ground Sensor Arrays ............................................................................. 18
2.26 Shortwave Spectrometer.......................................................................................................... 19
2.27 Surface Meteorological Instrumentation ................................................................................. 19
2.27.1 Develop Dynamic Rain Gauge Calibration Facility................................................... 19
2.27.2 Create Atmospheric Radiation Measurement Program Climate Research Facility
Wind Sensor Repair Facility ......................................................................................
20
2.27.3 Upgrade T/RH Probes and Wind Sensors for NSA Met Systems..............................20
2.28 Tandem Differential Mobility Analyzer.................................................................................. 20
2.29 Total Sky Imager..................................................................................................................... 20
2.30 Meteorological Tower Systems............................................................................................... 21
2.31 Vaisala Ceilmeter .................................................................................................................... 21
2.32 W-band Atmospheric Radiation Measurement Program Cloud Radar ................................... 21
2.32.1 Spare Extended Interaction Klyston Amplifier .......................................................... 21
2.32.2 Controller Modification.............................................................................................. 21
3 Future Instrumentation Planning.......................................................................................................22
3.1 Atmospheric Radiation Measurement Program Volume-Imaging Array................................ 22
3.2 Portable Raman Lidar.............................................................................................................. 22
3.3 Absolute Scanning Radiometer ............................................................................................... 23
3.4 High-Resolution Oxygen A-Band and Water-Band Spectrometer.......................................... 23
3.5 Rotating Shadowband Spectrometer Overhaul ....................................................................... 23
3.6 Narrow Field of View Radiometer for Atmospheric Radiation Measurement Program
Mobile Facility ........................................................................................................................
23
3.7 Add 1.6 :m Channel to Multi-Filter Rotating Shadowband Radiometer and Narrow
Field of View...........................................................................................................................
24

September 2006, DOE/SC-ARM/P-06-011.3
v
3.8
Aerosol Particle Sizing Spectrometer to Replace Optical Particle Counter at
Southern Great Plains..............................................................................................................
24
3.9 Future Microwave Radiometers .............................................................................................. 24
3.10 Modified Muti-Filter Rotating Shadowband Radiometer for Liquid Water Path ................... 24
3.11 Infrared Thermometers for the Southern Great Plains Extended Facility Sites ...................... 25
4 Small Business Innovation Research ................................................................................................ 26
4.1 Oxygen A-Band Spectrometer ................................................................................................ 26
4.2 Eye-Safe Ultraviolet Backscatter Lidar for Detection of Sub-visual Cirrus ........................... 26
4.3 Instrumentation for Remotely Sensing Aerosol Optical Properties –
Aerosol Phase Function...........................................................................................................
26
4.4 Unmanned Aerospace Vehicle-Suitable Cloud Radar............................................................. 26
4.5 Radiometer Radiosonde .......................................................................................................... 26
4.6 In-situ Measurement of Cloud Properties with Large Sample Volumes................................. 27

References
More filters

01 Jan 2005
Abstract: This paper offers a critical review of the topic of cloud–climate feedbacks and exposes some of the underlying reasons for the inherent lack of understanding of these feedbacks and why progress might be expected on this important climate problem in the coming decade. Although many processes and related parameters come under the influence of clouds, it is argued that atmospheric processes fundamentally govern the cloud feedbacks via the relationship between the atmospheric circulations, cloudiness, and the radiative and latent heating of the atmosphere. It is also shown how perturbations to the atmospheric radiation budget that are induced by cloud changes in response to climate forcing dictate the eventual response of the global-mean hydrological cycle of the climate model to climate forcing. This suggests that cloud feedbacks are likely to control the bulk precipitation efficiency and associated responses of the planet’s hydrological cycle to climate radiative forcings. The paper provides a brief overview of the effects of clouds on the radiation budget of the earth– atmosphere system and a review of cloud feedbacks as they have been defined in simple systems, one being a system in radiative–convective equilibrium (RCE) and others relating to simple feedback ideas that regulate tropical SSTs. The systems perspective is reviewed as it has served as the basis for most feedback analyses. What emerges is the importance of being clear about the definition of the system. It is shown how different assumptions about the system produce very different conclusions about the magnitude and sign of feedbacks. Much more diligence is called for in terms of defining the system and justifying assumptions. In principle, there is also neither any theoretical basis to justify the system that defines feedbacks in terms of global–time-mean changes in surface temperature nor is there any compelling empirical evidence to do so. The lack of maturity of feedback analysis methods also suggests that progress in understanding climate feedback will require development of alternative methods of analysis. It has been argued that, in view of the complex nature of the climate system, and the cumbersome problems encountered in diagnosing feedbacks, understanding cloud feedback will be gleaned neither from observations nor proved from simple theoretical argument alone. The blueprint for progress must follow a more arduous path that requires a carefully orchestrated and systematic combination of model and observations. Models provide the tool for diagnosing processes and quantifying feedbacks while observations provide the essential test of the model’s credibility in representing these processes. While GCM climate and NWP models represent the most complete description of all the interactions between the processes that presumably establish the main cloud feedbacks, the weak link in the use of these models lies in the cloud parameterization imbedded in them. Aspects of these parameterizations remain worrisome, containing levels of empiricism and assumptions that are hard to evaluate with current global observations. Clearly observationally based methods for evaluating cloud parameterizations are an important element in the road map to progress. Although progress in understanding the cloud feedback problem has been slow and confused by past analysis, there are legitimate reasons outlined in the paper that give hope for real progress in the future.

789 citations


Journal ArticleDOI
Abstract: Due to the spatially inhomogeneous nature of clouds there are large uncertainties in validating remote sensing retrievals of cloud properties with traditional in situ cloud probes, which have sampling volumes measured in liters. This paper introduces a new technique called in situ cloud lidar, which can measure extinction in liquid clouds with sampling volumes of millions of cubic meters. In this technique a laser sends out pulses of light horizontally from an aircraft inside an optically thick cloud, and wide-field-of-view detectors viewing upward and downward measure the time series of the number of photons returned. Diffusion theory calculations indicate that the expected in situ lidar time series depends on the extinction and has a functional form of a power law times an exponential, with the exponential scale depending on the distance to the cloud boundary. Simulations of 532-nm wavelength in situ lidar time series are made with a Monte Carlo radiative transfer model in stochastically generated inhomogeneous stratocumulus clouds. Retrieval simulations are performed using a neural network trained on three parameters fit to the time series of each detector to predict 1) the extinction at four volume-averaging scales, 2) the cloud geometric thickness, and 3) the optical depth at four averaging scales. Even with an assumed 20% lidar calibration error the rms extinction and optical depth retrieval accuracy is only 12%. Simulations with a dual wavelength lidar (532 and 1550 nm) give accurate retrievals of liquid water content and effective radius. The results of a mountain-top demonstration of the in situ lidar technique show the expected power-law time series behavior.

30 citations