• A Critical Evaluation of Correlation Methods in Climatology and Hydrology

      McDonald, James E.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1957-01-25)
      The sampling properties of three types of correlation coefficients are examined critically with reference to the practical problem of selecting a statistic optimally suited to correlation analyses in climatology and hydrology. Reasons are presented for concluding (1) that undue concern has been given the problem of non-normality of underlying frequency distributions, and (ii) that application of significance tests and determinations of confidence limits for the product-moment coefficient, r, are quite adequately achieved through simple use of the standard error of r. It is suggested that the growing tendency in climatology and hydrology to employ unnecessarily elaborate methods stems jointly from characteristic emphasis upon theoretical refinements found 1n most statistics references and from neglect on the part of users of statistics to examine the numerical magnitudes of these refinements in relation to basic data-precision and to desired precision of inference. The properties of a tetrachoric and a rank correlation coefficient are discussed, and it is concluded that in many geophysical applications, especially in cases of moderate sample sizes, the Spearman rank-difference coefficient should be regarded as the preferred correlation statistic. Em- . pirical comparison of these three coefficients are presented for a sample of precipitation data taken from a region (Arizona) where non-normality of precipitation frequency .distributions .. is known to be extreme. The rank difference coefficient is found to lie within one standard error of r for eleven of fourteen cases in this sample. The tetrachoric coefficient is found to be a much poorer estimate of r, yet in thirteen of fourteen cases it yields (on an approximation basis) the same inferences as does r with regard to existence of correlation.
    • A General Description of the Solar Energy Laboratory and its Initial Research Program

      Bliss, Raymond W., Jr.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1959-05-01)
    • A Study of the Trajectories and Diffusion Patterns of Ground-Generated Airborne Particulates under Orographic Wind Flow Conditions

      Kassander, A. Richard, Jr.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1957-05-15)
      In late June and early July, 1956, a series of experiments were performed to determine the wind structure over an orographic barrier and to ascertain whether ground-generated aerosols reach cloud heights in such a situation. Zinc sulphide particles were dispersed in an oil fog from a ground-located fog generator and collections were made using airborne impactors. Particles were found at elevations of at least 14,000 feet at distances out to at least 20 miles. However, "plumes" were found to be considerably broader than had been anticipated and the structure of the wind over a mountain ridge is judged to be substantially more complex than has been assumed in cloud-seeding operations.
    • An Automatic Printing and Totalizing Device for Solar Radiation Measurements

      Kassander, A. Richard, Jr.; Knowles, Lyle L.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1956-03-01)
      A device is presented which performs the time integration operation when hourly totals of incoming solar radiation are desired. This device, which is coupled to a standard self-balancing potentiometer type of recorder, samples the record each minute and prints out the indicated value. After sixty such samples are taken the total is then printed as well as the time of day. The operation starts and stops automatically at pre-set dawn and dusk times.
    • Arizona Statewide Rainfall

      Green, Christine R.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1959-11-30)
      A statistical method of deriving a statewide average annual preciptation value for Arizona has been developed in this study. The techniques employed and several examples showing how these calculations may be used to determine any given year's average rainfall amount for the state or for any smaller state subdivision are presented.
    • Back-Scattering of 3.21-cm Radiation by Water Bubbles

      Battan, Louis J.; Herman, Benjamin M.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1960-08-15)
    • Calculations of Doppler Radar Velocity Spectrum Parameters for a Mixture of Rain and Hail

      Martner, Brooks E.; Battan, Louis J.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1975-02-15)
      The radar reflectivity factors, the reflectivity-weighted mean terminal velocities (VT) and the standard deviations (cr) of the resulting VT Doppler spectra were computed for specified size distributions of rain, dry and wet ice spheres (taken to be hailstones) and rain with hail. Unambiguous estimates of the mean velocity and standard deviation can be obtained from a radar measurement of reflectivity for rain alone and dry ice spheres as a function of maximum sphere size. The results for wet ice spheres are strongly dependent on the thickness of the liquid water coating on the ice core. When rain and hail coexist, large values of reflectivity are associated with large ranges of VT and crv. If the shape of the hail size distribution is known, an independent measurement of the maximwn hailstone diameter or a knowledge of the standard deviation of the observed Doppler velocity spectrum can reduce the uncertainty in estimates of VT.
    • Calculations of Mie Back-Scattering from Melting Ice Spheres

      Herman, Benjamin M.; Battan, Louis J.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1960-09-01)
    • Calculations of Mie Back-Scattering of Microwaves from Ice Spheres

      Herman, Benjamin M.; Battan, Louis J.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1959-12-31)
    • Characteristics of Summer Radar Echoes in Arizona, 1956

      Ackerman, Bernice; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1959-07-08)
      This report describes an investigation of the radar data obtained during the summer of 1956. Descriptions of the evaluation and analysis techniques, of the basic data and of the findings of this study are given in considerable detail. For the convenience of the more casual reader, all discussion and a summary of the findings are contained in sections VI and VII.
    • Characteristics of Updrafts in Thunderstorms

      Battan, Louis J.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1978-08-31)
    • Cloud Photogrammetry with Ground-Located K-17 Aerial Cameras

      Kassander, A. Richard, Jr.; Sims, Lee L.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1956-06-01)
      A technique is presented in which a pair of ground-located K-17 aerial cameras are used on a 1.30 mile baseline to determine cloud ranges to one mile accuracy at 4o miles and cloud height measurements to within 500 feet at this range. Details of the power supply, vacuum supply, and camera synchronization requirements are discussed as well as methods used in analysis. In particular, a detailed discussion is given of the theoretical and practical errors encountered in such a photogrammetric technique.
    • Cloudiness Over the Southwestern United States and its Relation to Astronomical Observing

      McDonald, James E.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1958-02-24)
      A number of types of cloudiness statistics for Weather Bureau stations in the southwestern United States are analyzed in terms of their implications for astronomical observatory site-selection. In all but one of the analyses, Yuma proves to be distinctly superior to other stations with respect to clearness of skies. Lack of nearby mountain peaks extending above haze and dust layers plus poor seeing due to inevitably high thermal instability throughout much of the year render the immediate vicinity of Yuma astronomically unattractive, however. Hence the difficult task of comparing the relative cloudiness of the region roughly concentric with Yuma is the practical problem confronting the astronomer seeking new observing sites. Inherent limitations in available types of meteorological observations are disctissed; but these limitations are not precisely defined, since they are not quantitatively known to the meteorologist at present. In view of these uncertain limitations in each individual type of data, the safest procedure becomes that of assembling all possible types of independently observed data and assessing the site problem in terms of the overall implications of all of these data. ~e present report consists chiefly in such an assembly and assessment of meteorological data. In addition, a review of past studies of the site-selection problem is given. It is concluded that during the winter half-year (more significant to astronomical observing than the sunnner half-year for night-duration reasons), the area extending out about 200 miles northeast and east of Yuma 1s the best portion of Arizona for observing sites. Sites in this area will have clearer winter skies than those over coastal southern California, and will: be somewhat superior to those north of the Mogollon Rim where more frequent migratory cyclonic storms increase the mean winter cloudiness to values higher than those found to the south. The southeastern corner of Arizona is unattractive in the summer rainy season (July-August) due to high-frequency of thunderstorms, and equally undesirable in summer is the whole Mogollon Rim whose thunderstorm frequencies are nearly as high, on the average, as those of extreme southeastern Arizona. A rapid westward diminution of summer thunderstorm activity across southern Arizona (due to upper-level flow conditions governing moisture distribution over the Southwest) makes summer conditions increasingly more favorable from Tucson westward to Yuma; and in the winter the entire border area west of Tucson to and beyond Yuma is quite favorable. Haze and dust tops average about 5000 to 6000 ft. msl. in winter and probably 8000 to 10,000 ft. msl. in summer in southern Arizona. Areas of agricultural cultivation, as the Salt River Valley area around Phoenix, have a locally severe transparency problem. The general altitude of the haze and dust layers plus other seeing difficulties leave only a few peaks in southwestern .Arizona as feasible sites. A peak at 5672 ft. in the Harquahalas and Kitt Peak (6875 ft.) in the Quinlans seems to offer the the meteorologically best possibilities in .Arizona. Several California peaks considered by Irwin may be almost as favorable as those in southwestern .Arizona, but no first-order Weather Bureau station data are available for those areas. However, the only peaks above 6000 ft. msl. in the area. west of Yuma are those just south of San Jacinto Peak and these ranges undoubtedly have about as high a winter cloudiness as San Diego, which proves to be distinctly higher than either Tucson or Yuma.
    • Cooperative Punchcard Climatological Program, First Annual Progress Report

      McDonald, James E.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1955-11-15)
    • Cooperative Punchcard Climatological Program, Fourth Annual Progress Report

      Green, Christine R.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1958-11-15)
    • Cooperative Punchcard Climatological Program, Second Annual Progress Report

      DesJardins, Robert B.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1956-11-15)
    • Cooperative Punchcard Climatological Program, Third Annual Progress Report

      DesJardins, Robert B.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1957-11-15)
    • Detection of Hail By Means of Doppler Radar

      Battan, Louis J.; Theiss, John B.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1968-05-01)
      The doppler spectrum obtained by means of a vertically-pointing Xband pulsed doppler radar may yield information on the size distribution of hail in the free atmosphere. It is concluded that the quantity A in the size distribution curve for hail, N = N0-AD e is sometimes more than twice the values 2.27 or 2.93 cm -1 proposed by earlier investigators. It is also shown that when both rain and hail are present the variance of the 2 doppler spectrum may exceed 20 m2 sec-2.
    • Distillation of Saline Water Utilizing Solar Energy in a Multiple-Effect System Consisting of Separate Collector, Evaporator, and Condensor

      Hodges, Carl N.; Kassander, A. Richard, Jr.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1962-04-01)
    • Distribution of Relative Humidity and Dew Point in the Southwestern United States

      Sellers, William D.; Institute of Atmospheric Physics, The University of Arizona (Institute of Atmospheric Physics, University of Arizona (Tucson, AZ), 1960-02-01)
      This report consists of three basic parts. In the first, average monthly values of relative humidity are presented for between one and four hours of the day at 126 weather observing stations in the southwestern United States, including all of Arizona, New Mexico, Colorado, Utah, and Nevada, and parts of California, Texas, Idaho, and Wyoming. The nature, accuracy, and import of these data are discussed briefly. It is shown that the month with lowest average humidities varies systematically from March in central Texas to August in northern Nevada, antedating the westward movement of the Atlantic high pressure system, with its moist unstable air. In the second section, the distribution of dew point over the Southwest is discussed. High values are found on the windward sides of most of the larger mountain ranges, near bodies of water, and in heavily irrigated farmland; low values are concentrated at higher elevations and in the dry desert regions bounded by the Sierra Nevada Mountains to the west and the Rocky Mountains to the east. Hourly data for Arizona indicate that the diurnal variation of dew point is small, with a tendency for the lowest values to occur in the midafternoon in dry regions and in the early morning in moist regions, i.e., those with a surface snow cover or with considerable crop irrigation. The final section outlines a method of estimating the mean relative humidity from the mean temperature. Ordinary linear regression techniques are used, with a correction added to account for the systematic geographical distribution of regression errors.