HIAPER performance requirements include a maximum operating altitude of at least 50,000 feet, a scientific payload of 6,600 pounds, a minimum flight endurance of ten hours and a range of greater than 6,000 nautical miles.
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Progress has
been made in the procurement of a new high-altitude airplane,
called HIAPER. In summer 1999, NCAR/UCAR staff prepared a Draft
Request for Proposal (RFP), which includes the HIAPER Requirements
Document (HRD), the Proposal Evaluation Plan (PEP) and an Aircraft
Characterization Evaluation (ACE) document. The document was sent to
the vendors for review in November 1999 and March 2000. NCAR
organized a second Vendors Conference from 4-5 April 2000 in Boulder
to allow for final questions, several of which led to revisions
in the document. All in all, six evolving drafts of the RFP were
posted on the HIAPER
web site where they were available to potential vendors and
interested community members before the RFP was formally issued on 19
June 2000. Proposals from the vendors were due on 15 September 2000.
A French/US Instrumentation Workshop was held in Washington, D.C. from
6 to 8 June 2000 to discuss the state of airborne measurements and
science and instrumentation needs for the next several years. The
HIAPER Evaluation and Selection Team (EST) was appointed by the
Director of ATD and began evaluation of proposals received in
accordance with the Evaluation and Selection Plan in late FY 2000. A
final recommendation for award from the EST is expected by the end of
this calendar year. |
HIAPER performance requirements include a maximum operating altitude of at least 50,000 feet, a scientific payload of 6,600 pounds, a minimum flight endurance of ten hours and a range of greater than 6,000 nautical miles. |
| The HIAPER Advisory Committee (HAC), comprised of members of the atmospheric research community, was appointed in early September 2000 by the Director of NCAR and convened for its first meeting on 19 September 2000. An internal review of the EST recommendation by NSF/UCAR/NCAR and the HAC will be completed in mid FY 2001. The draft subcontract will be submitted to NSF for review and approval mid FY 2001. Because sufficient funding is not available, UCAR plans to award the contract in calendar year 2001. | |
Aircraft Improvements to the NSF/NCAR C-130 |
The NASA/AMES C-130 (front) was obtained from NASA to provide low-time engines and spare parts. |
| A major airframe inspection was due on the NSR/NCAR C-130 in the last month of FY2000. This inspection, which will extend well into FY2001, requires removal of flight-control surfaces to allow in-depth inspection for airframe corrosion and structural defects. The aircraft will be out of service for three to four months. A C-130B model acquired in FY 1999 from NASA has already provided rack and other specialty items for the NSF/NCAR C-130. The low-time engines from the C-130B were used to replace the high-time engines from the NSF/NCAR C-130. Although this required substantial rewiring of the electrical distribution system, it was a much more cost-effective solution than overhauling the existing engines. The inspection and new engines will substantially enhance the reliability of the NSF/NCAR C-130. The status of the NSF/NCAR C-130 inspection is available on line from the ATD web site. |
Jefferson County Airport Lease and Hangar Space Issues
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UCAR's long-term lease with JeffCo Airport expired on June 30,
2000. The UCAR Contracts Office negotiated with Jefferson County on a
new lease. The new lease is a long-term arrangement with two
significant changes from the current lease: 1) The property at the
airport will be leased annually at current market rates and 2) the
lease will contain explicit special conditions for use and weight
restrictions favorable to the operation of the NSF aircraft. Under
the new terms, Jefferson County agrees to allow UCAR to operate
aircraft having no more than 130,000 pounds gross-take-off weights at
no charge, provided that UCAR stays under the government exemption of
5,000,000 pounds per year. The new lease was signed in early FY
2001. Although expansion of hangar space to accommodate the NSF/NCAR fleet is a high priority, not much progress has been made. The NCAR hangar at JeffCo is too small to accommodate two large airplanes at the same time. As a result, one aircraft is continually exposed to changing weather conditions. Maintenance activities and project preparations are rendered inefficient by the need to shuttle aircraft into and out of the hangar during threatening weather.
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The NCAR Electra is 40 years old and is slowly approaching the end of
its lifespan. Once HIAPER joins the NCAR/NSF fleet, the Electra
will be taken out of service. Even though NCAR has a second,
spare-parts aircraft, parts and service contractor availability are
becoming an increasing concern. Since the airplane carries the NCAR
ELDORA, it will be necessary to find a substitute aircraft platform
for the radar to keep it available to the scientific research
community. In September 2000, NCAR met with the aircraft group of the
ONR Naval Research Lab to discuss the possibility of mounting ELDORA
on a NRL P-3 aircraft. The installation of ELDORA on any aircraft
will include physical installation of the radar, including
transmitters, receivers, data system, pressure bulkhead pass-throughs,
and rotodome, possible modifications to the aircraft
power-distribution system, and possible changes to ELDORA or other
research instrumentation on the aircraft. Due to modern technology it
is very likely that the ELDORA data system could be replaced with a
smaller, less power consuming, system which could fit in a single
aircraft rack saving space and 200+ pounds of payload. The response
from NRL was positive and negotiations will be continued in FY
2001.
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One of the ONR/NRL P-3s. NCAR has started negotiations with NRL about a new home for the ELDORA airborne Doppler radar, presently installed on the NCAR Electra. |
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ATD continued to provide substantial aircraft dropsonde data system
support to the USAF. ATD provided engineering services
and logistical support for ten GPS dropsonde
systems installed on USAF C-130 aircraft. ATD also provided
additional Sat-Com software development for the capability to send and
receive messages, installation of new system printers, and software
and hardware updates. ATD fabricated one GPS dropsonde system and
spares for delivery to Vaisala under its executed Memorandum of
Agreement and has been asked to fabricate another system including
spares. In FY 1999, ATD began development of the next-generation, automated GPS dropsonde system for use with high-altitude and non-piloted aircraft. The system currently used on all research aircraft requires significant operator involvement in dropsonde preparation, launch and data capture, which limits its range of aircraft application. The next-generation dropsonde contains a code-correlating GPS receiver that internally processes GPS position, reducing the onboard hardware requirements. In FY 2000, ATD worked closely with NASA on a design to incorporate an automatic launcher into an ER-2 belly pod, a concept that will also be applied to the new NSF/NCAR aircraft HIAPER. |
A GPS Dropsonde after launch from an airplane. |
| ICARUSS, also known as "Driftsonde", is a new atmospheric sounding system proposed for use in The Hemispheric Observing Systems Research and Predictability Experiment (THORPEX) in FY 2005 with a Pre-THORPEX experiment in FY 2003. ICARUSS will employ a thin polyethylene balloon to lift 44 kg payload of 24 dropsondes and system electronics to an altitude of 100 to 75 mb (53,000 - 60,000 feet). The balloon then will drift with prevailing upper-level winds. Dropsondes released every six hours will telemeter the data back to the balloon where it will be processed and stored. A compressed data set will then be sent via satellite to a ground station and on to the THORPEX control center for further processing. In FY 2000, a preliminary design of ICARUSS was developed by ATD and the first prototype system is scheduled to be built and tested in FY 2001. If the initial deployment is successful, several more prototypes may be built for a test program to track hurricanes from two island sites in the Caribbean in FY 2001. |
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ELDORA development in FY
2000 was limited to correcting several hardware-related problems that
surfaced during MAP. All other plans, such as development of
real-time CAPPI and dual-Doppler wind retrieval capabilities and the
rewriting of the post-processing data correction algorithm using
targets in the "no ground clutter" circle had to be postponed to FY
2001. ATD continued to work with the NSF to find a long-term home for
ELDORA after the Electra will be retired from service.
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The Electra in flight with ELDORA mounted on the tail. |
SABL while being put in a C-130 pod. | ATD continued its efforts in FY 2000 to upgrade SABL to operate in a cross-track scanning mode from within a C-130 pod. ATD also improved the sensitivity of SABL, concentrating on reduction of noise in the IR channel by developing better methods for alignment, and by constructing a hard target range at the Marshall field site. Commercial marine radar for use as eye safety radar for SABL, on the NSF/NCAR C-130 and the Electra, was researched but will have to be delayed until FY 2001. |
| An open-path, near-IR tunable diode laser (TDL) spectrometer originally developed by NASA's Jet Propulsion Laboratory for use on high aircraft platforms has been modified by ATD for use on the NSF/NCAR C-130 in the lower troposphere and in the boundary layer. The resulting water vapor laser hygrometer (LH) is tuned to water vapor absorption features near 1.37 µm and uses a shorter path length than employed in the earlier instruments. The NSF/NCAR C-130 LH was flown on about 25 flights, spanning water vapor concentration range from 0.005 g/kg to 10 g/kg. Data from the TOPSE and Sea Salinity mission flights are currently being analyzed and compared with the standard water vapor measurements. The data are being used for better insight into the true water vapor concentrations without influence from condensed phase water in the atmosphere. In FY 2000, work was done to accommodate the very high water vapor concentrations found during warm periods and in the tropics at low altitudes. The necessary laboratory hardware and procedures have been developed for the calibration of the LH over the pressure and water vapor gradients anticipated with use on the NSF/NCAR C-130. A method for scanning over both a strong and weak water vapor absorption lines within a single laser scan is used to cover the dynamic range that is necessary. Initial evaluation of the system indicated that the LH significantly improves existing capabilities and will eventually replace the cryogenic dewpoint sensor. In addition, work was done to improve instrument calibration curves and to evaluate the potential for high rate (8 Hz) measurements. |
 The Laser Hygrometer, attached to the outside of the NSF/NCAR C-130 aircraft, is an open-path diode laster tuned to measure water vapor near 1.37 um. Measuring water vapor in the atmosphere is one of the hardest tasks to accomplish. |
The Low Turbulence Inlet attached to the outside of the NSF/NCAR C-130 aircraft, allows researchers to collect large particles and aerosols. | In July 2000, scientists from the Universities of Hawaii and Denver tested the new porous-diffuser low-turbulence inlet (LTI), developed at the University of Denver with the help of the Design and Fabrication Services group. The LTI was flown with three other inlets on the NCAR/NSF C-130 in the Caribbean, using both dust and sea salt to test aerosols. Aerosols were analyzed using bulk chemical analysis of ions on filters, scanning electron microscopy of filters, TSI aerodynamic particle sizers and FSSP-3000 optical particle counters. Results showed that the LTI consistently admitted more particles to the airplane than did either the NCAR Community Aerosol Inlet or a shrouded solid-diffuser/curved-tube inlet. The LTI represents a significant advance in the ability to sample populations of large particles from aircraft. Its efficiency is near enough to unity to enable defendable studies of the distributions and impacts of both mineral dust and sea salt. |
Carbon monoxide measurement capability was significantly improved by replacing the aging gas filter correlation analyzer with a commercially available instrument that operates on the principle of vacuum UV resonance fluorescence and provides a detection limit of 2 ppbv and a 1-second or better time response. When fully implemented this will improve NCAR measurement capability in two ways, reducing the detection limit by a factor of 15 over the currently supported CO instrument, with a concomitant factor of 30-60 improvement in time response.
Evaluation and improvement of the RAF precision CO2 instrument has also been initiated. Changes have been implemented to improve the precision of this non-dispersive infrared absorption instrument to approach the state-of-the-art. Steve Wofsy's group at Harvard leads the community in this area, and discussions held with the Harvard group and with the Tans group at CMDL have been helpful in defining areas where improvement would be possible. Preliminary results from summer test flights indicate a typical precision of 70 ppbv.
Improvements were also achieved in the performance of the fast- and slow-response ozone instruments. Optically flat windows were installed in the slow-response instruments to eliminate transient problems encountered during intervals of rapidly changing humidity. The fast-response ozone instrument was modified to achieve performance specifications, which more closely match the requirements for eddy correlation flux measurements. In bench testing, the instrument now shows an approximately 5-Hz time response with a concomitant 1 ppbv detection limit.
As of this writing, the Ozone instrument is fully operational. The CO
instrument has arrived, and is being tested. The CO2 instrument has
had one successful test flight and final improvements are being made
to the instrument. Further test flights for the three instruments are
planned on the Electra in December. ATD plans to first deploy these
instruments during the ACE-Asia project. After this project, these
instruments should be available for routine deployment.
Cloud and Precipitation Particle Imaging
| ATD enhanced the capability for airborne measurement of ice particles through the purchase of the Cloud Particle Imager (CPI) built by SPEC, Inc. This new device uses state-of-the-art optical technology to obtain high-resolution, high-speed images of cloud and precipitation particles. In FY 2000, software tools for analysis of CPI data were developed and data from several field programs, including the Tropical Rainfall Measuring Mission (TRMM), have been available to test and evaluate this probe. The CPI project is a joint venture between ATD, MMM and several university and government groups involved with the TRMM program and will continue in FY 2001. ATD scientists also continued to collaborate with SPEC, Inc. in the testing and characterization of a new airborne cloud extinctiometer probe for measurement of cloud optical properties by supporting scientific evaluation of test data from a prototype extinctiometer probe developed by SPEC. | 
Close-up of an ice particle. |
| ATD continued work in FY 2000 on software and hardware upgrades to this advanced wind profiling radar. The addition of pulse coding to the software now provides the capability for transmitting more energy with no loss of resolution. Improvements to the control and data collection software have made the radar easier to use and more reliable. Robust wind analysis routines allow the radar to now carry out wind analysis and graphically present the results on the World Wide Web in near real-time. In FY 2000, the addition of PIRAQ to the MAPR hardware was completed, as was the replacement of the existing transmitter with one that should improve the output power by 6-8 dB. Major efforts continue to improve and automate the wind algorithm and the clutter removal software. MAPR observations of the passage of a downslope wind storm in Erie, Colorado (the lee of the Rocky Mountains foothills). Top and center: plots of Signal-to-Noise Ratio and vertical wind speed, with 1 minute resolution. Bottom: horizontal wind in clear air with 5 minute resolution. Note the persistent updraft near 0745 UT and downdraft near 0945UT, and higher frequency oscillations. The persistent features are consistent with a stationary lee wave, and higher frequency motions are progagating waves. |
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TAOS during its maiden flight in VTMX in October 2000. | Development of TAOS was completed in FY 2000 for deployment in the Vertical Transport and Mixing Experiment (VTMX) in Salt Lake City during October 2000. TAOS can be thought of as a portable, instrumented, tall tower, with up to eight sensor modules spaced along up to 1000 meters of line, suspended from a blimp-like balloon. Each module is connected to a single-card computer, eliminating the need for a ground-based processor rack and allowing instructions to be sent from the ground. Data is sent via RF modem to a laptop PC on the ground. |
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In FY 2000, ATD changed the basic BINET design to record data only at
the BINET hub. Analysis of BINET data was simplified since all the
data now reside in the same place and are already linked up in time.
By taking advantage of the connectivity of the Ethernet, ATD improved
its BINET capabilities by adding networking to the system. Several
different Ethernet router systems were purchased so that BINET
communications can be set up in a wide variety of field siting
situations. Full 24-hour duty generators for BINET were refurbished.
A wide-beam variable-gain antenna was also designed and built.
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 BINET data taken during the STEPS program. |
 The High Resolution Doppler Lidar in the lab. | A new frequency feedback loop has been incorporated allowing operation on shipborne and airborne platforms. In addition, the average power has been increased by more than an order of magnitude and the repetition rate has been increased to 1kHz. In FY 2000 the HRDL was modified to measure for the first time latent heat flux profiles and their divergence from an aircraft. During IHOP 2002, HRDL measurements will be taken simultaneously with measurements from a German water vapor DIAL of the German Aerospace Agency (DLR). A new data acquisition board based on PIRAQ III will be developed to allow collecting data with a repetition rate of 2kHz. |