Air Weather Service Research Articles

Statistical studies of an effective sunspot number

Two decades ago, the U.S. Air Force Air Weather Service space forecasting group began generating what was termed an effective sunspot number (SSNe) by fitting a model of the critical frequency of the F2 layer (ƒoF2) to observedƒoF2 values. Initially a preprocessing step in a larger analysis package, this parameter has taken on a life of its own and is now used in various applications for both forecasts and specification of the globalƒoF2 field. This paper describes the various ways in which this parameter is calculated, investigates the behavior of this parameter over solar cycle 21 (1976 through 1986), and compares it with other solar‐ionospheric indices, including R12, IF2, IG, and the Ionospheric Prediction Service (IPS) T index.

Finding the Site of the First Soviet Nuclear Test in 1949

Efforts by the U.S. government to detect the first Soviet atomic test began at least as early as 1946. Interception of radioactive debris from the first test was made by the Air Weather Service B-29 weather reconnaissance aircraft, which was equipped to filter particles from the air, on 3 September 1949 at 500 mb east of Kamchatka. The U.S. Weather Bureau was charged with trying to find the likely testing grounds from this first interception and a few later ones. The test site was found using backward air trajectories from the radioactivity detection line and a time of detonation to determine where to stop the backward trajectories. The explosion time, with large error bars, was obtained from radiochemical analysis of the particulate debris. In 1949, best time was estimated to be about 1500 UTC on 27 August. This was then combined with 500-mb backward trajectories to place the likely test site, incorrectly, near the northern part of the Caspian Sea. The uncertainties in the test time and in the calculated...

Solar wind monitor satellite

The need to predict accurately the occurrence of geomagnetic disturbances, which have caused blackouts and damaged power system equipment, is discussed. It is difficult for the US National Oceanic and Atmospheric Administration (NOAA) and the US Air Force Air Weather Service to jointly operate the Space Environment Services Center (SESC), the civil agency responsible for monitoring solar disturbances. The SESC observes the Sun and several geophysical parameters, including the Earth's magnetic field using both ground-based and space-based sensors. This effort is hampered by incomplete information, particularly the lack of information on the fluctuations of the solar wind. The effects of solar storms on man-made systems including radio communication and radar, spacecraft electronics, satellites, pipelines, and geophysical surveys as well as power systems, are described. The solar activity that causes the disturbances is examined. A proposed satellite to monitor the solar wind and improve forecasts is discussed, and the importance of a broad base of user support is stressed. >

Air Force Air Weather Service’s requirements for global meteorological data

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text Douglas A. Moore and Robert E. Peterson, "Air Force Air Weather Service’s requirements for global meteorological data," Appl. Opt. 23, 2474-2476 (1984) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Space Environment Laboratory

The National Oceanic and Atmospheric Administration's (NOAA) Space Environment Laboratory (SEL), along with several other NOAA programs, is slated for a major budget reduction in FY 1985, a reduction which would have a serious impact upon the space environment services now provided by the laboratory.SEL, jointly with the U.S. Air Force's Air Weather Service, operates the Space Environment Services Center (SESC) in Boulder, Colorado. SESC acquires, in near real‐time, world‐wide data on solar activity, on the terrestrial magnetic field, and on energetic particles at geostationary and polar orbiting satellite altitudes. Data are available to SESC from solar observatories operated by both the Air Force and a number of nongovernment organizations, the NOAA geostationary and polar orbiting satellites, and a U.S.‐Canadian magnetometer network.

Earlier warnings may be possible with tornado Doppler

Tornadoes in severe thunderstorms were detected by a powerful Doppler radar in Norman, Oklahoma, more than 20 minutes before they became visible to ground observers, adding at least 10 minutes to the time available for tornado warnings. These experimental observations were part of a cooperative effort by NOAA and the Air Force to test the tornado‐detecting performance of an experimental Doppler radar.Donald W. Burgess of the NOAA National Severe Storms Laboratory, Donald R. Devore of the Oklahoma City Weather Service Forecast Office, and Capt. Joel D. Bonewitz of the Air Weather Service also found that the Doppler radar and its hightechnology data handling and display systems showed unexpected promise in detecting conditions associated with the heavy thunderstorm rains that can produce lethal flash floods.

Selective Reconnaissance Program of the Western North Pacific

Faced with the loss, in November 1971, of the tropical cyclone reconnaissance provided by the U.S. Navy's Fleet Air Reconnaissance Squadron One and proposed reductions in the U.S. Air Force's 54th Weather Reconnaissance Squadron on Guam, a Technique Development Program was established by personnel of the Defense Meteorological Satellite Program (DMSP) site at Guam and the Air Weather Service's 1st Weather Wing in Hawaii. The purpose of this program was to establish the accuracy of satellite-derived tropical cyclone positions and intensity estimates and the resulting usefulness of such information when applied as the basis for warnings issued by the Joint Typhoon Warning Center. The results of this applied research program would determine whether a satellite-aircraft mix could accomplish future reconnaissance requirements. This mix, coined the Selective Reconnaissance Program, has become an established part of tropical cyclone reconnaissance in the western North Pacific. Resulting in a net savings of over ...

Dapp satellite observations of auroras

Figure 1 contains two photographs obtained from a military satellite that is part of the U.S. Air Force's Defense Systems Application Program (DSAP). The U.S. Air Force Air Weather Service Data Acquisition and Processing Program (Dapp) now routinely provides similar satellite photographs to the Environmental Data Service of the U.S. Department of Commerce National Oceanic and Atmospheric Administration at their National Geophysical and Solar Terrestrial Data Center in Boulder, Colorado, for copying and for general distribution. The data center then sends the original photographs to the Air Force Cambridge Research Laboratories for archiving.

The Air Force Global Weather Central operational boundary-layer model

A limited-area seven-layer physical-numerical model for the lower tropospheric region (surface - 1600m) is described. The grid interval, approximately 190km, is half that of the standard numerical weather-prediction grid used in the hemispheric free atmospheric operational model at the Air Force Global Weather Central (AFGWC). This model is an integral part of the complete AFGWC meso-scale (sub-synoptic) numerical analysis and prediction system and is used to provide greater horizontal and vertical resolution in both numerical analyses and forecasts. Important features of this boundary-layer model include: a completely automated objective analysis of input data; the transport of heat and moisture by three-dimensional wind flow; latent heat exchange in water substance phase changes; and eddy fluxes of heat and water vapor. Input data are conventional synoptic surface and upper air reports. Other operational AFGWC prediction models provide input in the form of horizontal wind components at the upper boundary and an estimate of cloudiness above the boundary layer. Forecasts for the lower boundary and surface layer are empirically derived. Despite some approximations which broadly simplify the real planetary boundary-layer processes, operational use for highly weather-sensitive Air Weather Service support indicates that the model is capable of producing accurate detailed forecasts for periods of up to 24h.

The Air Weather Service: its activities, problems, and challenges

the Air Weather Service: its activities, problems, and challenges

The Air Weather Service Winter Trajectory Test Program

Abstract The Winter Trajectory Test Program was conducted as part of the Air Weather Service Forecaster Assistance Program. The objective of this test was to determine if three-dimensional trajectories derived from the output of the Air Force Global Weather Central's six-level model are useful in the preparation of terminal forecasts. Headquarters Air Weather Service personnel evaluated forecasts prepared at detachments located in the central and eastern United States and modified some of these forecasts on the basis of trajectory information. The application of trajectory data improved the four-month verification of the terminal forecasts by 3.1%. Test procedures are discussed, and objective rules developed for the evaluation are presented.

An Experiment in the Use of Satellite Data in a Numerical Cloud Prediction Program

Cloud data derived from TIROS VII photographs over the North Pacific area were used to supplement synoptic surface cloud data in an automated layered-nephanalysis program. During the test period, cloud data from nine TIROS VII orbits were used in the automated layered nephanalyses. These nephanalyses provided additional moisture data input over sparse-data areas to the Air Weather Service Numerical Cloud Prediction program. The total-cloud cover forecasts were improved for 12-, 24- and 36-hr periods. Improvement in the layered-cloud forecasts also was found in the case of moisture decreases at the 700- and 400-mb levels. Other layered-cloud modifications were inconclusive. The importance of establishing a reliable initial moisture field over low-density areas for input to the cloud forecast program was confirmed. Although further refinements must be made in the designation of cloud layers and the merging of satellite cloud data with primary cloud observations, the study showed that satellite cloud data can be effectively processed as input to automated nephanalyses and cloud forecast programs.

The U. S. Air Force Programs in Meteorological Education and Training

HE prime justification for any military T organization during peacetime is training for a national emergency. The Air Weather Service (AWS) is charged with providing environmental support to the operating agencies of the U. S. Air Force (USAF) and to the U. S. Army. Since the Air Force performs its prime mission in the aerospace environment, it is logical that the Air Weather Service must participate actively in a large number of educational and training programs to insure that AWS is capable of providing completely adequate advice concerning the future state of the atmosphere. The success of USAF education and training programs is attested to by how well AWS has performed its mission in Southeast Asia during the present armed conflict. Officer Programs

Maximum Hurricane Surface-Wind Computation with Typhoon-Environment Data Measured by Aircraft

Tests were made during the 1963 typhoon season of a technique for computing maximum typhoon surface winds. The purpose was to estimate the capability of the Air Weather Service WB-47 to accomplish such diagnoses from dropsonde data in the environment of a typhoon and from radar measurements of its wall-cloud radius. Data were collected from WB-50 aircraft, flying at 700 mb, with 173 measurements in 10 typhoons. It is shown that 84 of the computed winds were within 10 per cent of the verifying winds as determined by the Joint Typhoon Warning Center in its operational function.

Numerical Prediction: An Exposition and Review for the Nonspecialist1

1 An address presented at the 155th National Meeting of the AMS. Published with permission of the Commander, Air Weather Service, U. S. Air Force.2 Lt. Colonel, U. S. Air Force.

Weather Reconnaissance by Airborne Time Lapse Camera

The operation, in a high flying airplane, of a simple 16 mm time lapse motion picture camera produces an excellent record of the cloud systems and other visual atmospheric patterns existing over large areas of continent and ocean. Over the past several years such records were obtained from both jet and propeller driven planes through the cooperation of the Boeing Airplane Company and the Air Weather Service, U.S.A.F. with the Munitalp Foundation. For best results it was found that the camera should be mounted at right angles or at 45 degrees with respect to the flight path and with a downward tilt of from five to twenty degrees depending on the cruising height of the plane. A two second interval was found to be suitable for good results with planes with an average speed in the range of 300–600 mph. Intervals of four to even ten seconds are permissible at these speeds for economy or convenience. When such a sequence is viewed as a movie, near clouds move by at a different rate from those in the middle or far distance thus giving an excellent illusion of three dimensions. Successive frames may be selected from a sequence and viewed in a stereoscope to get a three dimensional view of the area photographed. When projcted at sound speed in a movie projector, a film made with a two second interval sequence presents the illusion that the viewer is travelling through the sky at a speed of nearly 29,000 mph.

A Note on the Effect of Aircraft Exhaust on Airport Visibility

On several occasions reports have been received by Headquarters Air Weather Service of deteriorating weather conditions at an air base apparently caused by the landing of a number of jet aircraft. Such an occasion occurred at Goose Bay, Laborador in December, 1954. A detailed analysis has been made of this case and the probable cause of the phenomenon given.

Return of radiosondes requested by USAF Air Weather Service

Return of radiosondes requested by USAF Air Weather Service

A Note on the Effect of Aircraft Exhaust on Airport Visibility

On several occasions reports have been received by Headquarters Air Weather Service of deteriorating weather conditions at an air base apparently caused by the landing of a number of jet aircraft. Such an occasion occurred at Goose Bay, Laborador in December, 1954. A detailed analysis has been made of this case and the probable cause of the phenomenon given.

Low‐temperature fog at the Edmonton Airport as influenced by moisture from the combustion of natural gas

Quarterly Journal of the Royal Meteorological SocietyVolume 82, Issue 351 p. 99-99 Correspondence Low-temperature fog at the Edmonton Airport as influenced by moisture from the combustion of natural gas H. Appleman, H. Appleman Headquarters Air Weather Service, Andrews Air Force Base, Washington, D.C.Search for more papers by this authorG. W. Robertson, G. W. Robertson Dept. of Agriculture, Experimental Farms Service, Ottawa, OntarioSearch for more papers by this author H. Appleman, H. Appleman Headquarters Air Weather Service, Andrews Air Force Base, Washington, D.C.Search for more papers by this authorG. W. Robertson, G. W. Robertson Dept. of Agriculture, Experimental Farms Service, Ottawa, OntarioSearch for more papers by this author First published: January 1956 https://doi.org/10.1002/qj.49708235113AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume82, Issue351January 1956Pages 99-99 RelatedInformation