On the skydeck at Atqasuk, the new met pack (above right) and GPS receiver (circled at left) acquire data for the SuomiNet.

At the North Slope of Alaska, the ACRF operates a research site in the remote town of Atqasuk, Alaska, to provide continental Arctic data to the climate research community. The Atqasuk site is proving useful to climate modelers since this inland site is more homogenous and uniform than coastal sites during summer months. Enhancements to the instrument suite in Atqasuk last year led to a recent addition that solidified Atqasuk’s position on the international science map as a key site for atmospheric measurements. On July 15, 2007, Atqasuk instruments began providing meteorological data to SuomiNet, an international network of global positioning system (GPS) receivers. These receivers are 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 geographical information. The low-cost addition of the Atqasuk site to SuomiNet provides an additional meteorological datastream for use by the science community.

In 2006, scientific partners installed a GPS receiver at the ACRF Atqasuk site to provide a highly accurate geographic reference. The same type of GPS receiver is deployed at ACRF’s Tropical Western Pacific sites at Manus, Nauru Island, and Darwin, Australia, on behalf of SuomiNet. The relatively minor addition of a “met pack”—for measuring barometric pressure, temperature, and relative humidity—to the GPS receiver qualified the Atqasuk site for inclusion in the SuomiNet community. The same model of met pack is also deployed at 15 extended facilities at the ACRF Southern Great Plains site that are part of the SuomiNet. Estimates of precipitable water vapor at 30-minute intervals are now included in the gec30suomigpsX1.c1 data files available from the ARM Archive.

To ensure that ACRF precipitation measurements are as accurate as possible, the SGP rain gauges (white cylinder above left) are inspected every two weeks, are statically calibrated in the field every six months, and will now be dynamically calibrated on an annual basis using the system shown above.

The ACRF fills a unique position in the scientific community by obtaining long-term continuous measurements of cloud and radiation properties critical to climate modeling. Central to this mission is the ability to maintain and quickly repair instruments, as well as providing integrated instrument calibration processes to ensure ACRF provides high quality data products. In the past 15 years of operations, the ACRF Southern Great Plains (SGP) site has developed many onsite repair and calibration capabilities that have led to increased efficiencies and cost savings that benefit not just the SGP site and its users, but the other ACRF sites as well. In the past year, enhancements to various components of the site’s Radiometer Calibration Facility further increase its ability to provide timely and accurate data to the scientific user community.

A dynamic rain gauge calibration procedure was implemented in 2007. A basic rain gauge calibration is done by dripping a known amount of water into the gauge and reading the amount of water measured. However, this procedure does not take into account errors that might occur during a heavy rainfall event, a common occurrence during spring and summer in Oklahoma. A dynamic rain gauge calibration compares known “rainfall rates” generated by computer-controlled equipment to rates measured by the gauge being calibrated. Differences can then be accounted for in the rain gauge data processing.

The equipment necessary to calibrate multifilter rotating shadowband radiometers and other similar sensors was also recently acquired at the SGP. Because each instrument has seven detectors that require calibration and characterization at all solar viewing angles (sunrise to sunset), a very precise calibration setup is required, as well as a significant amount of time to complete the procedure. Calibration procedures have been formalized, staff training has been completed, and some calibration activities have already begun. This enhancement adds a significant and important calibration capability to the ACRF.

Applications are invited for a two-year fixed-term postdoctoral research fellow position to work on furthering our understanding of the land-sea contrast in tropical atmospheric convection and to improve its representation in global models. The successful applicant should be an active researcher with a Ph.D. (or equivalent) in atmospheric science or a related discipline. Salary range for a Research Fellow Level A will be $58,271 - $62,550 per annum and the location is the Clayton campus. Please send inquiries to Professor Christian Jakob, Tel: +61-3-9905-4461, Fax: +61-3-9905-4403, Email: christian.jakob@sci.monash.edu.au

Applicants should send a curriculum vitae, research interests and experience, list of publications, together with names and contact addresses of three references by email to Professor Christian Jakob, School of Mathematical Sciences, Monash University, by September 28.

The University of North Dakota’s (UND) Department of Atmospheric Sciences is seeking qualified applicants for a tenure-track faculty position in the area of Radar Meteorology. This faculty member will be expected to teach courses at the graduate and undergraduate levels, maintain a program of externally-funded research and direct graduate student research. A Ph.D. in atmospheric sciences or a related discipline is required. A proven record of publication and external funding and demonstrated expertise in teaching is highly desirable. This position will be filled at the Assistant/Associate Professor level, depending on qualifications.

The Department of Atmospheric Sciences is part of the John D. Odegard School of Aerospace Sciences at UND. The undergraduate program leading to a B.S. in Atmospheric Sciences was started in 1983 and now has approximately 60 majors. A Master of Science program was begun in the fall of 1998 and a Ph.D. program in the fall of 2006; 20 students are now enrolled in these graduate programs. Facilities include a 5-cm wavelength Doppler weather radar with dual polarization capability and two instrumented ground research sites. We are also planning to acquire a research aircraft platform. Additional information can be found on our web site: http://www.atmos.und.edu.

A review of applications will begin 1 November, 2007, and the position will remain open until filled. Salary will be commensurate with experience. Please send a curriculum vitae, statement of professional goals and the names and addresses of at least three professional references to: Prof. Michael Poellot, Chair of Search Committee, Atmospheric Sciences, Clifford Hall Room 400, 4149 University Avenue Stop 9006, Grand Forks, ND 58202-9006. Phone: 701-777-3180; Fax: 701-777-5032; Email: poellot@atmos.und.edu.

The Department of Atmospheric and Oceanic Sciences at McGill University is seeking
outstanding applicants for a tenure-track Assistant Professor position in the area of
atmosphere-ocean general circulation modeling. The successful applicant will be
expected to develop an active research program, supervise graduate students, and teach a
variety of undergraduate and graduate courses. Depending on the qualifications of the
successful candidate, hiring may be possible at either the Associate or Full Professor
level.

Preference will be given to candidates whose area of expertise is climate-change
dynamics.

A Ph. D. in atmospheric or oceanic sciences or a closely-related field is required.
McGill University is an English-speaking university located in Montreal, one of North
America’s most cosmopolitan cities. For more information about McGill University and
the Department of Atmospheric and Oceanic Sciences, please see http://www.mcgill.ca/meteo.

A hard copy (not via email) of the applicant’s curriculum vitae, research proposal, and
teaching statement should be sent to:

Dr. John R. Gyakum, Chair
Department of Atmospheric and Oceanic Sciences

McGill University
805 Sherbrooke Street West

Montreal, QC H3A 2K6
Canada
514-398-3760; fax: 514-398-6115

Candidates should also arrange to have three letters of reference sent directly to the above
address. In accordance with Canadian employment and immigration regulations, this
advertisement is directed to Canadian citizens and permanent residents of Canada.
However, applications from all outstanding candidates will be considered. McGill
University is committed to equity in employment.
The preferred starting date for this position is September 1, 2008.
Review of the applications will begin in December 2007 and continue until the position
is filled.

A 2-channel microwave radiometer (left) and a 12-channel microwave radiometer profiler (right) are part of a larger collection of instruments deployed at the ARM Mobile Facility site in Heselbach, Germany, in 2007.

Microwave radiometers (MWRs) are instruments used to measure emissions of water vapor and liquid water molecules in the atmosphere at specific microwave frequencies. Different MWRs are used to measure various frequencies, but the accuracy of all their retrievals is somewhat suspect, particularly when clouds are “thin”—less than 100 gm 2. In June 2007, a 6-month field campaign began at the ARM Mobile Facility site in Heselbach, Germany, to help scientists to unravel the different types of uncertainties inherent in the various radiometer measurements retrievals. Called the Cloud Microwave Validation Experiment, scientists will compare measurements from numerous MWRs deployed by both the ARM Mobile Facility and European collaborators taking part in the Convective and Orographic Precipitation Study (COPS). Their goal is to conduct intercomparisons between the instruments and to assess the data from multiple instruments for possible explanations as to the unresolved microwave uncertainties.

From the tropics to the Arctic, 50% or more of the clouds have liquid water paths below the 100gm 2 limit. Because the Earth’s radiative energy balance is particularly sensitive to small changes in the cloud liquid water path, small uncertainties in their optical properties can easily affect changes in the local radiative energy balance. For the climate research and modeling community, resolving such uncertainties would have a huge impact on related science issues, such as cloud radiative impacts and aerosol indirect effects.

In support of COPS, the ARM Mobile Facility instrument suite includes a variety of MWRs, including a 2-channel MWR, a 12-channel MWR profiler, and a new 90/150 GHz MWR. Collocated at the ARM Mobile Facility site are a European 90/150 GHz MWR and a 14-channel profiling MWR. In addition, water vapor and temperature-profiling information from frequent radiosonde launches, plus retrievals from a water vapor differential absorption lidar and temperature profiles from a Raman lidar will be available from the COPS deployment. Observations from this collection of instruments will produce an excellent database to address the unresolved microwave uncertainties.

The ARM Mobile Facility is hosting several guest instruments during COPS to support related but separate field campaigns. See the ACRF field campaign website for more information.