Perturbations to observed ambient neutral densities due to presence of an Orbiting Geophysical Observatory

Perturbations in density of ions and neutral particles in upper atmosphere due to OG

Collection and analysis of radar rainfall and satellite data for the Darwin TRMM experiment

The following subject areas are covered: video cloud camera (purpose, design, operation, data); special observing periods (SOP-2, SOP 2.5 - an extension of SOP-2); Garand algorithm; and warm rain

An investigation of surface albedo variations during the recent sahel drought

Applications Technology Satellite 3 green sensor data were used to measure surface reflectance variations in the Sahara/Sahel during the recent drought period; 1967 to 1974. The magnitude of the seasonal reflectance change is shown to be as much as 80% for years of normal precipitation and less than 50% for drought years. Year to year comparisons during both wet and dry seasons reveal the existence of a surface reflectance cycle coincident with the drought intensity. The relationship between the green reflectance and solar albedo is examined and estimated to be about 0.6 times the reflectance change observed by the green channel

The experimental determination of tyre model parameters

SUMMARY This report describes the analysis of a series of experiments on pneumatic tyres which were designed to test the various hypotheses: regarding the deformed shape of a tyre during the steering process. The experiments consisted of several separate tests first described in Ref. 1 and 2. a) The application of a point lateral force or a moment at one position on the tread band which is restrained at the centre of the wheel, and the measurement of the resulting lateral deflection of each point of the tyre perimeter. b) The application of a uniform force around the tyre perimeter on a hollow cylindrical former and applying a load at the centre of the wheel. c) Direct determination of tread band tension by cutting the tread band and bridging the cut by a dynamometer. d) Estimation of the bending modulus of the tread band by test on sections cut from the tread band. The analysis of the experiments is carried out by first transforming the test results into a Fourier series and determining the spectral content of the bending line with an harmonic analysis. Transfer functions of beam and string models are derived and applied to the test results. A method of considering a three parameter model is described

A study of the economic benefits of meteorological satellite data

Satellite data, while most useful in data poor areas, serves to fine tune forecasts in data rich areas. It consequently has a resulting significant economic benefit because, as previously stated, even one improved forecast per client per year can save each client thousands of dollars. Multiply this by several hundred clients and the dollar savings are sizeable. The great educational value which experience with satellite data gives undoubtedly leads to improved forecasts. Any type of future satellite data delivery system should take into account the needs and facilities of the user community to make it most useful

A biosequence of soils formed from loess and volcanic ash in the Western Kenai Peninsula, Alaska

In the western Kenai Peninsula, Alaska, the well drained Cohoe and Island soils have formed in a mixture of volcanic ash and loess. The Cohoe soils have some properties of Spodosols and support a climax spruce forest. The Island soils are classified as Inceptisols and occupy broad, shallow grass-covered depressions that occur as openings within areas of the forested Cohoe soils, Field evidence indicates that in western Alaska the forest is advancing at the expense of the grasslands. In soils high in volcanic ash or other pyroclastic materials that yield high amounts of amorphous materials, it is sometimes difficult to distinguish between a spodic and a cambic horizon by the kinds of measurements commonly made in the laboratory. Several lines of evidence indicate that Andepts are converted to Spodosols in a relatively short time following their occupation by spruce forest in western Alaska. The main objective of this study was to apply some of the physical and chemical studies which are commonly used to distinguish between spodic and cambic horizons high in amorphous materials. A second objective was to relate the soil forming factor of vegetation to the morphology of these soils. Two transects extending from the grass-covered Island soils to the forested Cohoe soils were chosen near Ninilchik on the southwestern. Kenai Peninsula. Samples from horizons were taken from representative pedons of an Island, a Cohoe, and a transitional soil on the forest grass border. Some of the chemical studies included: (1) cation exchange capacity, (2) exchangeable bases, (3) percent organic carbon, (4) percent nitrogen, (5) extractable acidity, (6) percent free iron, and (7) pH values determined in water paste, N KCl paste, and .0.1M CaCl2. In addition, pH values were determined in 1N NaF. X-ray, DTA, bulk density, and pyrophosphate dithionite extractable C, Fe, and A1 studies were made on the horizons of the sola. Percentage water retention at 15-bars was determined on air-dry, field-moist, and oven-dry samples. Particle size distribution was determined by the standard method of dispersion using hexametaphosphate preceding overnight shaking. In addition, results were compared on air-dry and field-moist samples. On selected horizons, ultrasonic sound was employed as an additional dispersant. The difficulty of wetting and differences in percentage water retention at 15-bars on field-moist and air-dry samples showed that these soils dry irreversibly. Particle size distribution suggested incomplete dispersion by all methods used. X-ray, DTA, and NaF pH values indicated a high content of amorphous material, but not a high content of allophane. The organic fraction was almost as important a part of the active fraction as was the clay in the chemical properties that were measured. Pyrophosphate dithionite extractable C, Fe, and A1 were similar at comparable depths in the three soils studied. The forested Cohoe and Transitional soils have thin albic hori-zons over reddish B horizons that have some properties of spodic horizons; the grass-covered Island soils have thick, dark umbric epipedons. The laboratory studies, however, revealed that the difference in measured properties were small

Application of lightning data to satellite-based rainfall estimation

Information on lightning may improve rain estimates made from infrared images of a geostationary satellite. We address this proposition through a case from the Cooperative Huntsville Meteorological Experiment (COHMEX). During the afternoon and evening of 13 July 1986 waves of showers and thunderstorms developed over and near the lower Tennessee River Valley. For the shower and thunderstorm region within 200 km of the National Weather Service radar at Nashville, Tennessee, we measure cold-cloud area in a sequence of GOES infrared images covering all but the end of the shower and thunderstorm period. From observations of the NASA/Marshall direction-finding network in this small domain, we also count cloud-to-ground lightning flashes and, from scans of the Nashville radar, we calculate volume rain flux. Using a modified version of the Williams and Houze scheme, over an area within roughly 240 km of the radar (the large domain), we identify and track cold cloud systems. For these systems, over the large domain, we measure area and count flashes; over the small domain, we calculate volume rain flux. For a temperature threshold of 235K, peak cloud area over the small domain lags both peak rain flux and peak flash count by about four hours. At a threshold of 226K, the lag is about two hours. Flashes and flux are matched in phase. Over the large domain, nine storm systems occur. These range in size from 300 to 60,000 km(exp 2); in lifetime, from about 2 1/2 h to 6 h or more. Storm system area lags volume rain flux and flash count; nevertheless, it is linked with these variables. In essential respects the associations were the same when clouds were defined by a threshold of 226K. Tentatively, we conclude that flash counts complement infrared images in providing significant additional information on rain flux

Use of microwave satellite data to study variations in rainfall over the Indian Ocean

The University of Wisconsin Space Science and Engineering Center mapped rainfall over the Indian Ocean using a newly developed Scanning Multichannel Microwave Radiometer (SMMR) rain-retrieval algorithm. The short-range objective was to characterize the distribution and variability of Indian Ocean rainfall on seasonal and annual scales. In the long-range, the objective is to clarify differences between land and marine regimes of monsoon rain. Researchers developed a semi-empirical algorithm for retrieving Indian Ocean rainfall. Tools for this development have come from radiative transfer and cloud liquid water models. Where possible, ground truth information from available radars was used in development and testing. SMMR rainfalls were also compared with Indian Ocean gauge rainfalls. Final Indian Ocean maps were produced for months, seasons, and years and interpreted in terms of historical analysis over the sub-continent