This liquid water plot from SSM/I global data shows long cloud bands and areas of scattered convection (red), including a fairly extensive cloud system in the vicinity of Manus Island in the Tropical Western Pacific (indicated by the white rectangle). (Larger image.)

For several years, the ARM Program has collected global satellite data for wind speed, precipitable water vapor, cloud liquid water, and rain rate over the ocean. From ascending and descending satellite passes, these data represent atmospheric state information that is useful for driving and diagnosing climate models, particularly in the tropics. The data sets, produced twice a day by Remote Sensing Systems (RSS), come from Special Sensor Microwave/Imagers (SSM/I) on board satellites involved in the U.S. Air Force’s Defense Meteorological Satellites Program. ACRF data systems staff recently completed a major effort in reviewing the needs for this data and converting it to NetCDF (network common data format) with associated image files for enhanced usability.

In 2002, RSS updated the algorithm used to produce the SSM/I data sets, followed soon thereafter by a reprocessing of all data from 1996. ACRF data systems staff used this opportunity to review ARM science needs and make any desired enhancements their SSM/I data collection script prior to replacing the associated data in the Archive. Two science needs became apparent: ARM trajectory work to determine tropical cirrus cloud origins, and rainfall measurements in the tropics. By increasing the longitudinal and latitudinal boundaries by 15 degrees, the expanded data would include much of the equatorial Indian Ocean, providing a broader frame of reference for research at the ACRF Tropical Western Pacific locale. To enhance user friendliness of the information, the satellite data were converted to NetCDF format. Quantities derived from the SSM/I data, including precipitable water vapor, are stored as a function of local equatorial crossing time (time of satellite overpass), latitude, and longitude. The data sets now also include thumbnail and full resolution images as rendered by the SSM/I.

With the conversion of the expanded satellite sensor data to NetCDF files complete, the new preprocessed data from 1996-01-01 through 2004-06-30 is now available from the Data Archive. The SSM/I data will be processed monthly on a 2-month delay, to allow time for sensor drift corrections to pre-applied by RSS.

With a new school year looming, ACRF staff involved in the Education and Outreach Program worked with the ARM communications team to develop and implement an updated Education website. The redesigned website includes updated content and a fresh look to complement the recent ARM website redesign. For continuity, the website still features the familiar faces of Professor Polar Bear, Teacher Turtle, and PI Prairie Dog (each representing an ACRF site), but now provides easier navigation and great new learning activities.

Targeted at students, the Study Hall webpage includes a variety of activities and information designed to pique the scientific interests of kids in grades K-12.

The Education website is now divided into three specialized and easy-to-navigate sections: Homeroom, Study Hall, and Teachers’ Lounge. Homeroom features information about ACRF education and outreach efforts, providing news, events and publications. Study Hall is a resource for students, containing quizzes, activities, and commonly asked questions and answers about climate, weather, and global warming. This area also includes a new “Just for Fun” page that offers coloring pages, word seeks, and more. The Teachers’ Lounge provides teachers with sample lesson plans, activity ideas, and valuable background information.

A DOE stipulation for ACRF funding is to provide educational resources to anyone interested in learning more about climate sciences, weather, research techniques, or instrumentation. To this end, the website serves as a cost effective and globally accessible reference. In addition, Education and Outreach staff frequently participate in targeted public education venues such as WeatherFest, and work closely with communities that host ACRF sites.

The Southern Great Plains site celebrates 10 years of continuous data!

A milestone for the global climate research community comes from the U.S. Department of Energy research facility at the Southern Great Plains site. This year marks the 10-year anniversary of the world’s largest and most extensive climate research field site for studying the effects of clouds and solar radiation on Earth’s atmosphere.

“Our overarching scientific objective is to improve scientific understanding of the fundamental physics related to interactions between clouds and radiative processes in the atmosphere,” said Wanda Ferrell, program director for the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Program. “The data set provided by 10 years of continuous measurements represents a major contribution in research related to climate observations as well as for advancing climate modeling efforts going on around the world.”

To read more about this milestone, see the full press release.

Approximately 20-25 ARM Program scientists will present their research at the 2004 International Radiation Symposium in Busan, South Korea, during the week of August 23-28, 2004. The theme of this year’s symposium is “Current Problems In Atmospheric Radiation.” ARM Program participation in the symposium includes several invited talks, including one by Chief Scientist Tom Ackerman. During the session on Surface Measurements and Field Experiments, he will give an invited talk entitled “Ground-Based Measurements of the Radiative Properties of the Atmosphere: A Look to the Future.” The talk will discuss the advantages of long term data sets provided by the ARM sites, then focus on current and future research using multiple data sets and temporal statistics to understand the atmosphere, as well as the potential for a global network of sites to conduct atmospheric research. Additional ARM scientists will discuss their research during invited talks, presentations, and poster sessions.

Hosted by the Korean Meteorological Society and the Atmospheric Environment Research Institute at Seoul National University, the symposium provides an opportunity for scientist around the world to review the current status of radiative transfer, molecular and aerosol radiative properties, radiation budget, weather and climate applications, and measurements from ground-based stations, balloons, aircrafts, and satellites. According to Hyo-Sang Chung, President of the Korea Meteorological Society, “This Symposium will act as a bridge to strengthen the cooperative relationship among relevant organizations.” Because of the strong international makeup of the ARM Program, this symposium is a key event for furthering collaborations among its scientists around the world.

See the program (a PDF) for a complete list of invited talks, presentations, and posters.

Media Contact: Lynne Roeder, 509.372.4331
Technical Contact: Tom Ackerman, ARM Chief Scientist, 509.372.6032

A milestone for the global climate research community comes from a DOE research facility located in north-central Oklahoma. This year marks the 10-year anniversary of the world’s largest and most extensive climate research field site for studying the effects of clouds and solar radiation on Earth’s atmosphere.

“Our overarching scientific objective is to improve scientific understanding of the fundamental physics related to interactions between clouds and radiative processes in the atmosphere,” said Wanda Ferrell, program director for the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Program. “The data set provided by 10 years of continuous measurements represents a major contribution in research related to climate observations as well as for advancing climate modeling efforts going on around the world.”

The Southern Great Plains (SGP) site was chosen for its relatively homogeneous geography and easy accessibility, wide variability of climate cloud type and surface flux properties, and large seasonal variation in temperature and specific humidity. It was the first of three heavily instrumented research locales established around the globe by the ARM Program. These three locales now make up the ARM Climate Research Facility, a national user facility for conducting climate research.

Scattered among approximately 55,000 square miles of mostly cattle pasture and wheat fields at the SGP site are more than 30 specialized in situ and remote-sensing instrument clusters for measuring surface and atmospheric properties. Data collected by these instruments provide continuous, detailed ground-based measurements about wind speed and direction, water vapor transport, temperature, cloud properties and distribution, radiation flux, and other parameters important to atmospheric research.

“Climate research is focused on long-term trends, both at the regional and global scale,” said Tom Ackerman, chief scientist for the ARM Program. “You can’t make any real progress with pieces of data from here and there. To truly understand what is happening over the long haul, you need data sets that provide continuous measurements spanning long periods of time.”

Though the first set of instruments was installed in 1992, additional capabilities were added in the succeeding few years. The complete suite of permanent instruments at the SGP site provide a 10-year collection of unprecedented data for the scientific community as they investigate the causes and effects of global climate change.

# # #

Additional information about ARM Program Science and the ARM Climate Research Facility
is available at www.arm.gov.

The SuomiNet software integrates a network of global positioning systems to distribute spatially and temporally dense atmospheric data in real-time from broad and diverse regions.

ARM Program scientists are concentrating on developing techniques for obtaining the best possible water vapor measurements under a wide range of conditions (clear/cloudy, day/night, etc.). In 2001, 15 SuomiNet systems were installed at selected facilities at the ACRF Southern Great Plains (SGP) site to obtain these measurements (see photo at right). SuomiNet is an international network of global positioning system (GPS) receivers and meteorological instrument packages, configured and managed to generate near real-time estimates of precipitable water vapor in the atmosphere, total electron content in the ionosphere, and other meteorological and geodetic information. To acquire total column water vapor measurements at its Tropical Western Pacific (TWP) sites, the ACRF is deploying a similar system developed by COSMIC, including GPS and meteorological packages (from Paroscientific).

The COSMIC system is based on the Trimble netRS receiver, which incorporates a linux system that permits the receiver to be connected directly to the network, eliminating the need for a separate dedicated computer for communication and data transfer.

To ensure compatibility with the existing SuomiNet data processing systems, ACRF operations staff began working with COSMIC representatives in July to configure and test the systems at SGP prior to deployment to the tropics. Siting requirements, such as a clear view of the sky down to an elevation angle of 5 degrees, the need to be away from metal structures, etc., were considered in the testing. Testing was successfully completed, and installation at TWP will occur once the final setup designs and necessary operations and maintenance documents are delivered to site operations staff.

Approximately one megabyte of data for each SuomiNet site will be delivered with the new system each day. These additional data will help ARM researchers quantify improvements to clear sky radiative transfer, which are currently limited by the uncertainty in atmospheric water vapor distribution profiles.

Thanks to quick actions on the part of numerous ACRF operations staff, an Extended Range Atmospheric Emitted Radiance Interferometer (ER-AERI) is on its way to Oliktok Point, Alaska. As part of an ongoing instrument comparison, two ER-AERIs (one a permanent ARM instrument, the other a “visitor”) have been operating side by side since January 2004 at the ACRF North Slope of Alaska’s Barrow site. The visiting ER-AERI (from the University of Wisconsin) and the instrument shelter developed for it at Barrow were slated for barge transport to Oliktok in late August to support ARM’s Mixed Phase Arctic Cloud Experiment (M-PACE). In late July, the team was surprised by a notice from the barge company that their departure date from Barrow had moved up about three weeks, to the August 6 timeframe. Following a flurry of phone calls and some scrambling of schedules, the AERI instrument mentor essentially dropped everything and managed to arrange a flight up to Barrow to disassemble and pack the ER-AERI components in time for the barge trip. The alternative of delaying shipping and transporting the equipment and shelter by plane to Oliktok would have cost around $30K (vs. $3K by barge), potentially precluding the use of the instrument during the experiment.

As part of M-PACE, the ER-AERI will join a suite of remote sensing instruments, aircraft, and balloons (tethersonde and radiosondes) to collect in situ observations of mixed-phase stratus cloud properties. A “typical” AERI measures the spectral radiance of the sky directly above the instrument in the range of 20-3 microns; the ER-AERI is suited for the reduced water vapor concentration in the Arctic atmosphere and viewing into the so-called “dirty window” from 18 to 25 microns. The AERI shelter, which consists of a partitioned insulated shipping container, will also house the radiosonde system and provide onsite shelter for the Oliktok operations crew during the experiment.

Development of the new 2-channel NFOV (right) benefited greatly from a comparison with the original 1-channel version (left).

Development of a new, two-channel narrow field of view (NFOV) radiometer for the ACRF Southern Great Plains site is nearly complete. The two-channel NFOV replaces a similar single-channel instrument that was destroyed by lightning in June 2002, and adds a 673 nm (red) measurement to the measurement at 870 nm (near infrared). Repairs to the original NFOV were completed and calibrated first, so that it could be used to check the calibration of the 2-channel version. This comparison proved to be a very valuable step, as it revealed a subtle electronics problem in the new version that caused a drift in the readings. With the problem solved, completion of the new instrument is imminent, and deployment at SGP is anticipated in September.

Development of the two channel unit required construction of new instrument housing and incorporation of a new data logger. The new NFOV radiometer collects data using a CR10X measurement and control system (from Campbell Scientific). Instrument output consists of a time series of 1-second observations of zenith spectral radiance. These radiance data can be used to characterize the optical properties of clouds. The additional 673 nm radiance measurement is an important element in developing cloud optical depth algorithms and retrieval methods, particularly for broken cloud fields.

Want to participate at the 2004 American Geophysical Union (AGU) Fall Meeting in San Francisco? Then, it is time to submit your abstracts before the September 9 deadline! The Fall Meeting will cover topics in all areas of geophysical sciences and provides an opportunity for researchers, teachers, students, and consultants to present and review the latest issues affecting the Earth, the planets, and their environments in space. It is estimated that 10,000 geophysicists from around the world will attend, and it is a regular meeting that the ARM Program and ARM Climate Research Facility attends. To submit your abstract by September 9, use the Online Submission Form. Abstracts submitted by mail must be received at AGU headquarters by September 1.