Enabling Innovative Field Experiments and Measurement Campaigns

Two ASU grad students, Bryan Paris and Brad Busby launch a balloon that gather sounding data in support of CuPIDO - Cumulus Photographic Investigation and Doppler Observations experiment - that took place in the Santa Catalina mountains near Tucson, AZ in July and August, 2006. The purpose of CuPIDO is to examine the development of the earliest stages of the thunderstorms. The clouds begin to form over the highest peaks each morning and the reliability of the formation makes these areas natural "cloud laboratories". The sounding data that was gathered by this balloon and the radar data gathered by the high-resolution radar aboard the University of Wyoming King Air during this experiment may help researchers improve the forecast models used by the National Weather Service and ultimately provide more accurate and timely warnings.

The accuracy, robustness, and performance of weather, climate, and chemistry models depend on sound theory and accurate measurements. EOL’s leadership in the area of field program planning and implementation is considered the crown jewel of its achievements.  EOL maintains a large suite of state-of-the-art NSF-funded Lower Atmospheric Observing Facilities (LAOF), without which collection and analysis of data and subsequently, understanding of atmospheric and earth processes would be impossible.

Maintaining a large degree of flexibility and responsiveness, EOL serves as the coordination point for scientific field campaigns, offering services ranging from advice and consultation during the initial stages of the planning process to the development of field design and project implementation plans, the provision of tailored and specialized logistics support, the fielding, operation and maintenance of scientific instrumentation in the field, real-time data communication development and support, organizational and operational management to achieve the scientific objectives as well as the coordination of educational activities related to field projects. 

• Virtual Operations Center - [Highlight]
• Facilities Assessment
• EOL User Workshop
• Field Programs
• T-REX
• MIRAGE
• IMPEX
• CuPIDO
• T-AMMA
• REFRACTT
• BUFEX I
• KESS
• Planned Field Programs
• Observing Facilities Assesment Panel
• USCG Healy Support
• Instrumentation Improvements
  • REAL
  • S-Pol

Virtual Operations Center [Highlight]

The VOC enabled feedback loop. The VOC is essentially a field operations center that resides on the Internet itself, where participants can interact from wherever in the world they happen to be. The feedback loop is centered on integrated observational data displays and near–real time computer model outputs will be created, and the updated information will facilitate continuous, interactive planning as day-to-day missions are carried out.

Field experiments in the atmospheric sciences have grown in complexity, in part due to enhanced capabilities of our observing platforms and models as well as more available access to a whole array of new operational networks (e.g. satellites, mesonets, weather service radars, etc.) and forecasting products. During a field campaign, these data are sent to an on-site Operations Center and used in the real-time direction of observing platforms and subsequent analysis to plan future missions. Advances in communications and information technology provide an opportunity to significantly improve our ability to meet the science-driven requirements of these centers, now and in the future. 

In FY06, EOL staff submitted a proposal to NSF for the VOC to use in field experiments in the atmospheric sciences. The VOC seeks to formally address the challenges of building these centers in using new technologies that are being developed across UCAR by providing new capabilities in visualization, forecast model assimilation, real-time data management and network-based collaborative tools which will lead to more efficient use of our observing platforms and improved field project datasets. The VOC will also expand the field participation of interested researchers, staff, students and others at remote sites.In FY06 EOL engaged in extensive collaboration with staff across UCAR, to gain insight into community needs and in May 2006 we formally submitted the proposal to the NSF. EOL anticipates a funding decision by the NSF in early FY07 after which staff will build prototypes for the VOC and engage the community in the first VOC workshop.

For more information see this item in the FY05 NCAR Annual Report

Facilities Assessment

In order to provide NSF and NCAR with a detailed understanding of all existing and emerging observational facilities, EOL is leading an effort to "take stock" of all observational facilities available across the community, including government agencies, universities, national laboratories, international organizations, and private companies. The goal of this assessment is a web-based inventory available to all investigators seeking specs, allocation process, availability and location of the observing systems. EOL will maintain and update this web based asset for the community. The assessment will include both instruments that are supported and made available to the community and those that are not generally accessible, for example, those only available to the principal investigator. A comprehensive survey like this has never been done before.

For more information see this item in the FY05 NCAR Annual Report

EOL User Workshop

EOL is finding new ways to reach out and get direct feedback from the community we serve. To that end, FY06 marked the beginning of a plan for a multi-day EOL User Workshop tentatively scheduled for early Summer 2007. While planning for this first in a series of workshops has just begun, the main goal of this meeting is to closely interact with EOL’s user community on issues related to EOL support and services including field campaigns, data management systems, airborne and ground based instrumentation as well as new developments and the implementation of new technology.

Field Programs

In FY06, EOL assisted in the implementation and conduct of two major field campaigns: MIRAGE and T-REX field operations. Services entailed the provision of essential field staff such as Operations Directors and Aircraft Coordinators, assistance in mission planning, coordination with aviation and military institutions, platform coordination, coordination of operational and science meetings and overall information dissemination and communications. EOL also provided logistics support to both programs, including arrangements required for fielding scientific and technical personnel and equipment, international arrangements, permits and clearances, shipping and customs, contracts and leases, meteorological support, communications, security and safety issues, as well as financial services and local staffing.

EOL staff also provided advice to the scientific steering groups of several large-scale projects in their initial planning stages. By actively participating in project-related planning activities, EOL helped shape the ideas for several large projects including the Westerns Atlantic Tropical Transition and Genesis Experiment (WATTAGE), The Sierra Hydrometeorology Atmospheric River Experiment (SHARE), the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX II) ,and the Convective and Orographically-Induced Precipitation Studies (COPS).

Terrain-induced Rotor Experiment (T-REX)

	EOL's Gary Granger sets up part of the Mobile Integrated Sounding System (MISS) during T-REX. The sounding system measures winds, temperatures, and other weather variables. It is giving researchers insights into severe types of atmospheric turbulence, including mountain waves and rotors, that form over the Sierra Nevada and other mountain ranges.

T-REX was the second phase of a coordinated effort to explore the structure and evolution of atmospheric rotors, as well as associated phenomena in complex terrain. T-REX field activities took place in the Owens Valley, CA in March and April 2006. Owens Valley lies to the east of the southern Sierra Nevada, which is the tallest, steepest, quasi two-dimensional topographic barrier in the contiguous United States. Mountain waves and attendant rotors are know to reach particularly striking amplitude and strength there. A network of about 135 different ground-based in situ and remote sensing measurements were deployed both upwind and within the Owens Valley during the two month period, with most of them centered on Independence, CA. T-REX was also the first “official” field campaign for the NSF/NCAR G-V (HIAPER), which flew at very high altitudes in the upper troposphere and lower stratosphere deploying dropsondes and making in situ flight level measurements. Accompanying it at the mid-altitude tropospheric levels was the BAe146 jet from the United Kingdom and at lower altitudes, the University of Wyoming King Air turbo-prop aircraft, carrying a cloud radar.

In addition to the G-V, EOL provided a large number of NSF facilities and supporting services during the project including one MGAUS system that provided soundings upstream of the southern Sierra Nevada in the vicinity of Visalia, CA; three Integrated Sounding Systems, including the first deployment of the improved Mobile ISS (MISS) in the Owens Valley; three Integrated Surface Flux Facilities (ISFF) for the first time using 120 ft ROM towers; the REAL lidar; Field Project Support staff for operations planning and coordination; and Data Management and Field Support.

In summary, T-REX conducted a successful field campaign, with an above average number of mountain wave events and rotors. One surprise was that the G-V encountered much less turbulence at high altitudes than forecast by models, especially during cases of strong wave breaking on 16 and 26 April 2006.

Megacity Impacts on Regional and Global Environments (MIRAGE)

	NSF/NAR C-130 Chief Pilot Henry Boynton (r) and Pilot Ed Ringleman (l) conduct a pre-flight briefing with their crew during MIRAGE. Based in Veracruz, on the Gulf of Mexico, the aircraft carried an extensive chemistry package to sample the aerosols and gases that comprise the pollution plume over Mexico City.

In March 2006, EOL supported the MIRAGE project, spear headed by lead scientist Sasha Madronich (NCAR/ACD). The focus of the campaign was Mexico City, the second largest metropolitan area in the Americas and infamous for its air pollution. “Attracted” by the dull haze that hangs over the city most days, researchers from close to 50 universities and organizations descended on Mexico City for one of the most complex chemistry campaigns ever undertaken. While previous studies primarily focused on the characterization and amount of pollutants emitted in the atmosphere, the MIRAGE researchers were specifically interested in the chemical and physical transformation of air pollutants as aerosols and gases interact while a plume is moving downwind, and how those plumes may impact regional and global air quality, climate, and ecosystems.

MIRAGE was one of four simultaneous field campaigns collectively called the Megacity Initiative: Local and Global Research Observations or MILAGRO. NSF, DOE, NASA and several other agencies funded the participation and operation of six aircraft, three ground sites, balloons, sondes, lidars, and several weather and chemical models. EOL staff participated in the campaign with the NSF/NCAR C-130, conducting coordinated flights with other aircraft. Based in Veracruz, east of the capital on the Gulf of Mexico, the aircraft carried an extensive chemistry package to sample the aerosols and gases that comprised the pollution plume. In addition to supporting C-130 flight operations, EOL staff was also responsible for operational and systems support at the Operations Center in Veracruz and worked closely with UCAR E&O to assist in an extensive educational component.

Overall, the campaign was scientifically very successful. Scientists encountered a multitude of different pollution conditions which was not limited to urban pollution but also includes smoke from regional and agricultural fires and dust events.

Intercontinental and Megacity Pollution Experiment (IMPEX)

EOL also supported the second MILAGRO segment – IMPEX, which focused on intercontinental pollutant transport. Two weeks after the end of MIRAGE, the NSF/NCAR C-130 joined the NASA DC-8 in Seattle, WA to examine the transport, evolution, and impact of Asian pollution on North America. With a similar payload as MIRAGE, investigators measured key species related to the chemical and physical transformations of gaseous and aerosol pollutants as the Asian plume approached the northwest Pacific coast. The NASA DC-8 was equipped to make similar measurements at some mid point in the air mass’s transit of the Pacific.

Cumulous Photogrammetric, In-Situ and Doppler Observations (CuPIDO)

CuPIDO researchers sought to examine the development of the earliest stages of the thunderstorms that form during the summer monsoon season over the Catalina Mountains in southern Arizona. In the area, thunderstorm clouds begin to form over the highest peaks each morning and the reliability of the formation makes these areas natural "cloud laboratories". In contrast to conventional “storm chasing” where investigators intercept the weather systems, researchers measured conditions prior to the storms beginning and monitored the way that the initial, shallow clouds interacted with and modifed the environment as they developed. The information gained during this experiment will help improve the forecast models used by the National Weather Service and ultimately provide more accurate and timely warnings. EOL supported CuPIDO with 10 ISFF and 2 MGAUS systems. The University of Wyoming King Air, a small, dual engine aircraft that carries a high-resolution radar also captured data.

THORPEX - African Monsoon Multidisciplinary Analyses (T-AMMA)

Eight driftsondes were launched from Niger, Africa in August and September 2006 in support of the hurricane genesis research during the THORPEX portion of the African Monsoon Multidisciplinary Analyses (T-AMMA) project. Each driftsonde gondola dropped between 20 and 40 of the new miniature sondes during thier flights, which lasted about six to seven days in the air, crossing Africa and the majority of allowable air space in the Atlantic before being cut down.

In Summer 2006, EOL conducted a pilot field experiment to explore the roots of hurricane genesis. T-AMMA was also first ever driftsonde field campaign, proving the concept of a stratospheric balloon carrying a gondola of dropsondes to be released on command at very high altitudes. Working closely with the French space agency CNES, the project took place in August and September 2006 in Zinder, Niger in Sub-Saharan Africa. A total of eight gondolas were launched during the project with each driftsonde gondola dropping between 20 and 40 of the new miniature sondes. Each balloon spent about six to seven days in the air, crossing Africa and the majority of allowable air space in the Atlantic before being cut down. The driftsondes sampled troughs in easterly waves and made multiple measurements in the forecast area of tropical cyclogenesis. T-AMMA piggy-backed on the bigger AMMA project, which tries to improve the knowledge and understanding of the West African Monsoon (WAM) and its variability. The majority of AMMA's scientific goals are driven by a societal need for improved predictions of the WAM due to its impact on West African nations. EOL also provided a dropsonde system on the NASA DC-8 during the NASA portion of AMMA.

Refractivity Experiment For H2O Research And Collaborative operational Technology Transfer (REFRACTT)

The REFRACTT experiment was conducted from June through August 2006 in northeastern Colorado. Very high resolution measurements of water vapor variability and transport in the convective boundary layer were obtained by SPOL, CHILL, several GPS receivers and one MGAUS system. One of the scientific objectives of REFRACTT was to assess potential improvements these measurements may have in numerical model forecasts of quantitative precipitation. The applications goal focused on collecting radar refractivity data on the NEXRAD (WSR-88D) radars and to demonstrate the forecast value of this field to NWS forecasters. The ultimate, longterm goal is to implement radar refractivity measurements on the national network of operational radars.

Bunny Fence Experiment (BUFEX I)

BuFEX I was the first of two field campaigns that focus on the influence of land use and landscape heterogeneity on atmospheric circulation and cloud formation. With its 700 km long distinct, sharp boundary between croplands and undisturbed vegetation areas, SW Australia is an ideal location for studying human induced landscape heterogeneity and natural, undisturbed environment, and their impact on climate, cloud formation and regional hydrology. The project was conducted in December 2005 near Perth Australia. Two mobile GAUS systems collected high quality upper air soundings data in support of the overall science objectives. A second field phase, covering winter-time conditions, is planned for Summer 2007.

Kuroshio Extension System Study (KESS)

Students from universities in Japan and Hawaii prepare to launch a balloon during the Kuroshio Extension System Study (KESS) In June and July of 2006. This oceanographic project focused on the Kuroshio Extension (KE) region east of Japan, which is a vigorously meandering boundary between warm subtropical and cold northern waters of the Pacific. GAUS sounding data collected will help in gaining new insights into atmospheric boundary layer adjustments to sharp sea surface temperature fronts, the formation and variations of fog and stratus cloud deck north of the KE, and the ocean's role in determining and maintaining storm tracks.

One GAUS system was installed on the RV Melville to support a primarily oceanographic project that focused on the Kuroshio Extension (KE) region east of Japan. The KE is a vigorously meandering boundary between the warm subtropical and cold northern waters of the Pacific. A second, important feature consists of a recirculation gyre that exists to the south of the KE. The overall goal of this program, which was part of CLIVAR, was to identify and quantify the dynamic and thermodynamic processes that govern the variability of and the interaction between the KE and the gyre. The area was chosen because it is one of the most intense air-sea exchange regions where the warm Kuroshio waters encounter the cold dry air masses coming from the Asian continent. It has been shown that variations in the KE system strongly affect North American climate. GAUS data collected will help gaining new insights into atmospheric boundary layer adjustments to sharp sea surface temperatures fronts, the formation and variations of fog and stratus cloud deck north of the KE, and the ocean's role in determining and maintaining storm tracks.

Planned Field Programs

Structure and Evolution of Diurnal Cold Air Pools and Seiches in Small Closed Basins (METCRAX)
EOL will provide one ISS and seven ISFF in support of the METCRAX experiment, which will take place in October 2006 in Arizona. The project is designed to investigate the meso- and micro-scale structure and evolution of the stable boundary layer within, above and in the vicinity of the Arizona Meteor Crater. The crater was chosen as it represents an ideal, simple-shaped, and small closed basin cut into a nearly homogeneous plane. The experiment calls for continuous monitoring of the wind, moisture and temperature structure of the air flow approaching the Meteor Crater and the responses to the flow within.

Inhibition of Snowfall by Pollution Aerosols (ISPA 2006)
ISPA studies the link between pollution aerosols and snowfall rates in the Mount Werner area, near Steamboat Springs, Colorado. For the second time, the project will use the EOL ISS-MAPR facility in early 2007 to obtain temperature and humidity profiles with altitude, cloud top height and temperature, depths of the snow layer, crystal fall speed and riming extent. The 2007 study will use the CSU-RAMS mesoscale model to forecast cloud properties, processes, precipitation formation and precipitation rates.

Canopy Horizontal Array Turbulence Study (CHATS)
The objective of CHATS is to make spatial measurements of the velocity and scalar turbulence fields in a uniformly vegetated canopy using arrays of sonic anemometer/thermometers augmented with fast response water vapor and carbon dioxide sensors. With this spatial information, the three-dimensional fields of velocity and scalar fluctuations will be studied to quantify turbulence transport processes and coherent structures throughout the canopy layer. CHATS will add to the data that were collected during two previous, related field programs – HATS and OHATS.

CLIvar MOde water Dynamics Experiment (CLIMODE)
The CLIMODE project is another CLIVAR-related oceanographic project that intends to clarify the effect of dynamics of 18 degree water (EDW) by describing the formation, evolution, storage, dispersal and large-scale consequences of EDW. The expected end result is a better understanding of air-sea fluxes in high exchange regions of the ocean and improved ocean physics parameters for inclusion into climate models. The shipborne ISS will contribute to these measurements by providing basic wind and thermodynamic profiles for the boundary layer by providing measurements of vertical wind and Doppler spectra continuously within over the oceans surface.

Ice In Clouds Experiment (ICE-L)
Based at JeffCo airport, the NSF/NCAR C-130 will support the ICE-L experiment from 1 March through 6 April 2007. The scientific goal of the project is to show that under given conditions, direct ice nucleation measurements, or other specific measurable characteristics of aerosols, can be used to predict the number of ice particles formation by nucleation mechanisms in selected clouds. The investigators seek improved quantitative understanding of the roles of thermodynamic pathway, location within the cloud, and temporal dependency.

Pacific Atmospheric Sulfur Experiment (PASE)
PASE is a comprehensive study devoted to the chemistry and physics of sulfur in the lower regime of the remote marine troposphere will be conducted from 1 August to 5 September 2007 east of the island of Kiritimati (Christmas Island). State of the art instruments will be installed on the NSF/NCAR C-130 to make accurate and high speed airborne measurements of sulfur dioxide, dimethyl sulfide, dimethyl sulfoxide, dimethyl sulfone, methane, sulfuric acid, hydroxyl radical, ammonia, water vapor, ozone, hydrogen peroxide, liquid water, temperature, pressure, wind velocity, cloud condensation nuclei, and thesize, composition and thermal properties of aerosols.

OFAP

Twice a year, EOL hosts the Observing Facilities Assessment Panel (OFAP) and coordinates among panel members, PIs, facility providers, EOL staff and NSF to assess the feasibility and cost of NSF-funded field projects. The OFAP is an NCAR-driven community process that provides technical and operational assessment of requests associated with the use of NSF’s Lower Atmospheric Observing Facilities (LAOF) in the field. The panel, which is composed of a diverse pool of scientists with broad-based experience in observational studies of earth system sciences, meets bi-annually at NCAR to provide valuable feedback and evaluation to facility managers and the user community concerning experiment design, data management issues and the appropriate and efficient use of NSF resources as related to a specific field campaign. The comments and technical evaluation presented by the OFAP, together with feasibility analyses and cost estimates provided by facility managers, are taken into consideration before a final decision is made by individual NSF program officers whether to fund a project.

USCG Healy Support

Over the past several years, JOSS/FODM provided data support for a number of Arctic projects, including SHEBA, SBI, and ATLAS. As part of this effort, FODM staff developed expertise in supporting the US Coast Guard icebreaker Healy, which collects data on summer cruises in the Arctic. This support has been requested by the NSF, via the Lamont-Doherty Earth Observatory, on an ongoing basis. In FY 2006 EOL staff have continued to support SBI data meetings, and accompanied the Healy on 2006 shakedown and data collection cruises, assisting with the collection and management of data and the operation of satellite receiving systems. Expertise gathered in this effort promotes the operation of GIS for EOL’s use. It is anticipated that NSF will continue to desire this level of support for 2007 and future years.

Instrumentation Improvements

REAL

NCAR's Raman-shifted Eye-safe Aerosol Lidar (REAL), developed by EOL scientists, is one of the few lidars that can be used in highly populated areas. The eye-safe and scanning capability expands the lidar's applications to include mapping urban atmospheric pollutants, and studies of dispersion very near the surface of the earth. NCAR's REAL was used in the T-REX field project, while another REAL, built by EOL for ITT, was deployed by the Department of Defense for unattended surveillance of aerosols in Washington, DC.

EOL’s Raman-shifted Eye-safe Aerosol Lidar (REAL) made its debut deployment for an NSF sponsored field campaign - T-REX - in March 2006. In spite of its busy operational schedule, EOL staff found time to make many important modifications and improvements to this unique eye-safe lidar to extend its capabilities. EOL scientists and engineers added a robust aerosol backscatter capability, positioning it to become one of the world's only rapidly-scanning, calibrated aerosol lidars in the world. Construction began on a new transportable lidar facility that will allow the use of the sensitive instrument in more remote locations. EOL also began developing backscatter depolarization sensitivity capability on the REAL, which would allow it to sense the actual shape of aerosol and cloud particles. Finally, EOL software engineers have developed sophisticated software which will allow complete control of the system, as well as the aquisition, display and processing of REAL data.

REAL Aerosol Backscatter Calibration
Implementaing accurate calibration methods is a challenging task, but a state-of-the-art, scanning lidar with aerosol backscatter calibration can be used by a wide variety of community investigators in areas of exploration that include, but are not limited to: impact of aerosol and clouds on the atmospheric radiation budget, biogenic aerosols, cloud microphysics, and model validation. The calibrated REAL will provide:

• more comprehensive data sets from field experiments that use the lidar;
• higher quality data sets;
• improved understanding and predictability of the role of aerosols on climate change;
• the ability to compare backscatter measurements from different dates and locations;
• the ability to begin assembling trends in aerosol scattering;
• the ability to begin relating aerosol backscatter to other air quality parameters and issue respiratory health warnings;
• the ability to estimate the concentration of weaponized aerosols;
• a technology that has commercial and tech-tranfser value.

EOL staff made first steps in 2006 to add a robust aerosol backscatter calibration capability to EOL’s Raman-shifted Eye-safe Aerosol Lidar (REAL) by identifying a gas with molecular absorption features near REAL’s wavelength. The group determined that hydrogen cyanide (HCN), a common telecommunications reference gas, has the appropriate properties at low pressures.  A single absorption line of HCN will be used to block the Mie/aerosol backscatter in one channel of the receiver and obtain the Rayleigh/molecular intensity. The second step was to determine if REAL’s transmitter was sufficiently stable near the HCN line and able produce laser light with the necessary spectral purity. EOL Engineers and Summer Engineering Intern Tomas Avilez spent most of the summer confirming that it is possible to control REAL’s transmitter to the level necessary. The next steps in FY07 will be to build a custom receiver that will allow the separation of molecular (Rayleigh) from aerosol (Mie) backscattering spectrally and test the system from the lab.  We are planning to have most of the laboratory evaluation complete by February 2007.

New Transportable Lidar Facility
Transporting sensitive lidar equipment over highways by truck and operating high-tech equipment in remote field locations is challenging work. EOL expects this new facility will encourage the use of our lidar systems in field deployments and contribute an attractive new component to the international lidar community, fostering interest and new collaborations in the area of lidar remote sensing. EOL began construction of a new transportable lidar facility in FY06. The new ground-based facility will include two shipping containers and an air-ride trailer. The containers will be transformed into a modern optical laboratory and a data acquisition and system control center. The facility will be available for deploying the next generation REAL as well as other lidar systems, such as those in CAPRIS and resulting from collaborations with other national labs and universities.

The facility will consist of a 48-foot long air-ride flat-bed trailer and two shipping containers custom modified for lidar operations. One “seatainer” will constitute a state-of-the-art optical laboratory and the other will house a data acquisition and system control center. Special care is being given to the design of internal structures so that sensitive laser and optical equipment are not damaged during long shipments—sometimes over rough roads. The new facility will enable fielding of new lidars such as the next generation calibrated REAL, and eventually, any of the CAPRIS lidars. During the first half of FY07, EOL staff will complete fabrication of the container housing the optical laboratory and refurbishment of the trailer and if possible, will complete the command and data acquisition control center.

Polarization Sensitivity on REAL

	Left: the heart of REAL’s receiver: a polarization beam splitter cube separates the parallel and perpendicular components of backscattered radiation into two detection channels.  Right: a scan through two aerosol plumes; one consisting of droplets (blue) and the other crystals (red).

In order to extend the usefulness of REAL to applications requiring information on aerosol type and cloud phase. EOL began developing backscatter depolarization sensitivity capability on REAL.  The motivation for this endeavor was to add the ability to sense the shape of aerosol and cloud particles which can be used to infer whether they are droplets or crystals.  This information is particularly important in studies that require the identification of aerosol type or the phase of clouds. The capability also has significant usefulness in the delineation and discrimination of potentially hazardous aerosol plumes from industrial or military sources. In FY07 we would like to improve the depolarization sensitivity by replacing the gold-coatings on our beam-steering unit mirrors with highly reflective dielectric polarization insensitive coatings.  This will eliminate a small angular-dependence we see in the depolarization ratio measurements. Also, we would like to increase the bandwidth and matching of the detector/amplifier modules in order to improve range resolution and reduce the depol ratio error near sharp aerosol gradients.

Lidar Data Processing
As REAL has evolved over the last few years, EOL staff have developed software to acquire data, control the system, display the data, and process the data. These pieces have been developed in Labview, IDL, and C with Open GL.   Acquisition, control and display must be done in real-time and have robust communication interfaces with instrument components such as electric motors, position indicators, power meters, etc. In FY07 we will develop software to extract two-dimensional vector motion fields from the REAL scans through advanced feature tracking and correlation methods.  Although the vectors derived from this technique may not be the same as the wind vectors from an in situ or Doppler lidar, they are not substantially different under a majority of conditions and therefore act as a good surrogate for sensing the wind field when Doppler systems are not available and when the other virtues of REAL are required (i.e. range, scan-speed, resolution, etc.) We intend to bring together talent from EOL, IMaGe, and RAL to accomplish this.

S-Pol

S-Pol and CHILL

NSF currently supports two S-band radar systems in the vicinity of Colorado’s Front Range: the CHILL National Radar Facility in Greeley, managed by Colorado State University, and the NCAR S-Pol Facility, managed by NCAR’s EOL.  The S-Pol, with dual-wavelength and dual-polarization radars configuration, is the only transportable radar in the world. It is capable of describing precipitation processes from cloud initiation to precipitation microphysics.  Many operational types of radar are now becoming polarimetric around the world. Perhaps most importantly for the US, the national network of radars will be polarimetric by 2010 -2012. There is a dearth of qualified people who can work with polarimetric radars and their data. The NCAR scientist and engineers play a key role in research, education and development and validation of weather forecast and quantitative precipitation estimation. An important component of this role includes having state-of-the-art radar such as S-Pol at NCAR.

While CHILL and S-Pol already cooperate on many efforts, a more formal combination of those efforts might result in some modest cost savings to both groups, while freeing up some energy to renew pursuit of developments that have long been on the lists of both facilities.  Any formal collaboration, however, should ensure that the best features of the two facilities are not unnecessarily compromised.

There are a few ideas worth pursuing in any extension of cooperation between S-Pol and CHILL.  Some of these efforts, namely, data archiving, radar processor development, sharing antenna and data exchange format are currently underway, or are being discussed, or can be fast-tracked. Another possible collaboration is with NASA via GPM (Global Precipitation Measurement). GPM will advance precipitation measurement capability from space through combined use of active and passive remote-sensing techniques. NASA will be conducting seven or eight GV (Ground Validation) experiments from about 2009 through 2016. Funding would be at about $250K per year. Both the NEXRAD program and the possible NASA GV experiments represent a significant cost sharing of the S-Band radars. Other collaboration may be possible. In this way the S-Band radars remain available to the scientific community while significant cost burden is unloaded from NSF. 

NCAR's S-Pol Radar is set against the majestic backdrop of a summer thundercloud which looms over the front range of the Colorado Rocky Mountains. The radar, along with NCAR's MGAUS sounding system, CSU's CHILL radar and several GPS receivers were deployed during the Refractivity Experiment For H2O Research And Collaborative operational Technology Transfer (REFRACTT) in an effort to improve precipitation forecasts by enhancing the observed field of water vapor.

Ka-band retrieval

S-Pol is being upgraded with the latest radar processor and transmitter for it to continue to serve as a world class facility and as a test-bed for supporting the planned polarization and signal processing upgrades to NWS radar network. After the Rain in Cumulus over the Ocean (RICO) experiment (2004/05), EOL engineering staff determined that the Ka-band radar required significant improvements in the receiver, transmitter, timing subsystem, data acquisition hardware, and processor software. These improvements were vital to the success of the Ka-band participation in the Refractivity Experiment for H2O Research and Collaborative Operational Technology Transfer (REFRACTT).

The Ka-band radar receiver was redesigned to improve the reliability of the system, and electronics was added to aid with system calibration and data quality. The transmitter magnetron was replaced with a longer life magnetron to improve system reliability, and the processor code was modified to accommodate the system changes. In FY07, EOL researchers plan to analyze the data collected during REFRACTT, publicize the capabilities of the Ka-band to the user community, and further improve the system reliability. The data collected during REFRACTT will be used in combination with S-band radar data to retrieve a path integrated value of the water vapor content from the atmospheric attenuation at the two wavelengths. Publication of results from the water vapor retrievals will demonstrate the usefulness of the Ka-band radar to the radar user community. We also plan to write an instrument description paper to publicize the enhanced capabilities of the S-Pol and Ka-band system.