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Temperature and wind data are presented from 70 small meteorological sounding rockets launched from eight selected launch sites in the Western Hemisphere. Table 1 gives a complete listing of the launch sites involved and the altitude of temperature and wind observations successfully completed.
Simultaneous Mariner and Explorer data are used in the present paper to show that the large-scale gradient in the bulk velocity of the solar wind observed by Coles (1972) is a heliographic latitude gradient. A value of roughly 15 km/sec/deg for the gradient is derived by a correlation technique employed by Coleman and Rosenberg (1971). A simple model of the velocity/latitude dependence is developed and is shown to be consistent with a direct comparison of the observed Mariner and Explorer velocities. The gradient inferred from the Mariner and Explorer data is compared with values obtained from corresponding analyses of Vela and IPS data.
A CO2 cloud tracking technique to determine simultaneous heights and velocities of cloud motion winds is presented. Using animated CO2 channel imagery from VAS (Visible Infrared Spin-Scan Radiometer Atmospheric Sounder), multi-level cloud situations are separated into high, middle and low level cloud motion wind vectors by the CO2 slicing method. The VAS CO2 channel radiometric values are used in the CO2 absorption method to assign quantitative heights to the cloud vectors; cloud top pressures are determined from the ratio of the deviations in cloud produced radiances and the corresponding clear air values for three CO2 channels in a radiative transfer equation formulation. Two case studies are presented that show CO2 cloud-motion wind vectors to be in good agreement with radiosonde wind observations and CO2 cloud heights to be within a 50 mb rms deviation of radiosonde, bispectral and stereo height determinations.
Disturbances in the heliosphere which occurred during two of the most active periods of the sun during the present solar cycle, in June and July 1982 and April and May 1978, are qualitatively simulated using the method of Hakamada and Akasofu (1982). A first-order spatial and temporal construction of flare-generated shocks and their multiple interactions with each other and with cororating interaction regions is obtained. A comparison of the results with solar wind observations from Pioneer 10, 11, and 12 suggests that some major flares occurred behind the solar disk during the two periods. The present method provides some qualitative information on how such a series of intense solar flares can greatly disturb both the inner and outer heliospheres. A long-lasting effect on cosmic rays which occurs in conjunction with such disturbances is discussed.
The two major disturbances in the heliosphere during the present sunspot cycle, the event of June to August, 1982, and the event of April to June, 1978, are simulated by the method developed by Hakamada and Akasofu (1982). Specifically, an attempt was made to simulate the effects of six major flares from three active regions in June and July, 1982, and April and May, 1978. A comparison of the results with the solar wind observations at Pioneer 12 (approximately 0.8 au), ISEE-3 (approximately 1 au), Pioneer 11 (approximately 7 to 13 au) and Pioneer 10 (approximately 16 to 28 au) suggests that some major flares occurred behind the disk of the sun during the two periods. The method provides qualitatively some information as to how such a series of intense solar flares can greatly disturb both the inner and outer heliospheres. A long lasting effect on cosmic rays is discussed in conjunction with the disturbed heliosphere.
The deflection of the Gulf Stream caused by a topographic feature - the Charleston Bump, located offshore of Savannah, Georgia - results in a quasi-stationary cyclonic eddy - the Charleston Gyre which is situated over the continental slope east of Charleston and Cape Romain. Occasionally, the upwelling associated with this eddy produces an enhancement in the surface layer primary production that is great enough to be detected by the Nimbus 7 coastal zone color scanner (CZCS). In this note a CZCS image with simultaneous hydrography, current, and wind observations is presented that documents an unusual manifestation of the gyre. In addition to the CZCS image a Seasat synthetic aperture radar (SAR) image is included that clearly indicates the presence of the eddy adjacent to the Gulf Stream front.
The present multivariate analysis method for surface pressure and winds incorporates ship wind observations into the analysis of surface pressure. For the specific case of 0000 GMT, on February 3, 1979, the additional data resulted in a global rms difference of 0.6 mb; individual maxima as larse as 5 mb occurred over the North Atlantic and East Pacific Oceans. These differences are noted to be smaller than the analysis increments to the first-guess fields.
Two microbursts that occurred simultaneously and were produced by two neighboring storms on June 22, 1982 have been examined using Doppler radar analyses and PAM surface network wind observations. The development of the microbursts is described, and the probable importance of forcing mechanisms is considered. It is found that a sounding conductive to deep convection with a very dry, unstable boundary layer gives rise to hail storms which produce microbursts associated with high-reflectivity cores. The two microbursts were associated with intensifying shafts of very high reflectivities. Convergence into the area of downdraft within the dry layer just below the cloud base, evidence of low reflectivity notches in the neighborhood of the microburst downdrafts, and subsaturated surface conditions in the microburst outflows suggest active evaporation processes may be an important source of energy for these two microbursts.
A method by which satellite and surface measurements can be compared in order to validate satellite wind observations is presented. The regression method requires knowledge of the expected differences (due to atmospheric variability and differing averaging) between perfect satellite and perfect buoy measurements. A model for estimating these differences is described. The regression method is applied to comparisons between Seasat Scatterometer (SASS) and U.S. National Data Buoy Office buoy data. Comparisons indicating a dependence of SASS accuracy on sea-surface temperature are summarized.
The solar cycle dependence of wind parameters below 100 km on the basis of long term continuous ionospheric drift measurements in the low frequency range is discussed. For the meridional prevailing wind no significant variation was found. The same comparison as for winter was done for summer where the previous investigations gave no correlation. Now the radar meteor wind measurement values, too, showed a significant negative correlation of the zonal prevailing wind with solar activity for the years 1976 to 1983. The ionospheric drift measurement results of Collm have the same tendency but a larger dispersion due to the lower accuracy of the harmonic analysis because of the shorter daily measuring interval in summer. Continuous wind observations in the upper mesopause region over more than 20 years revealed distinct long term variations, the origin of which cannot be explained with the present knowledge.
Solar wind observations suggesting wave-particle interactions via ion-cyclotron resonances are reviewed. The required power at high frequencies is presumably supplied via a turbulent cascade. Tu's (1987) model, which considers a turbulent cascade explicitly, is outlined. In the solar atmosphere, resonance absorption is considered. The meanings of the cusp and Alfven resonances are discussed, and it is shown how energy gets pumped into small scales. It is shown that resonance absorption can heat the corona and spicules in a manner consistent with observations, if turbulence provides an eddy viscosity.
The paper presents the results of an ultraviolet survey of stellar winds in 62 Be and 43 normal B stars covering spectral types B0.5-B5 and luminosity classes V-III. Excess wind absorption in Be stars over that detected in normal B stars is found in C IV and Si IV, confirming results of previous surveys. The stars showing excess wind absorption also show one or more shortward-shifted discrete absorption components, suggesting that much of the excess wind absorption is in the form of discrete absorption components. Evidence is presented that the high-velocity and highly ionized stellar wind observed in some Be stars is a function of latitude.
This paper discusses results obtained during the period between August 1981, and February 1983, by the instruments aboard the Dynamic Explorer-2 (DE-2) mission, with emphasis placed on the data obtained through the direct measurements of thermospheric vector neutral winds and ion drifts. The DE-2 instrumentation used to obtain the vector neutral-wind observations is described together with the information obtained on the dynamics of the thermosphere. Special consideration is given to the theoretical model development and the ongoing data-theory comparative studies. The progress made during the first five years of the DE mission is summarized.
Airborne Doppler lidar data obtained by NASA near the top of the PBL in the central valley of California are analyzed. The experimental conditions and quality of the data are described. Wind vectors are produced on a geographic grid divided into 1-km square cells. The resulting wind field has features similar to those seen in ground level wind observations. It is suggested that, although the analysis is labor intensive and cumbersome, it produces a previously unattainable high-resolution depiction of air flow over a broad region.
Calculations of radiative equilibrium temperatures on Triton's rough surface suggest that significant condensation of N2 may be occurring in the northern equatorial regions, despite their relatively dark appearance. The bright frost is not apparent in the Voyager images because it tends to be concentrated in relatively unilluminated facets of the surface. This patchwork of bright frost-covered regions and darker bare ground may be distributed on scales smaller than that of the Voyager resolution; as a result the northern equatorial regions may appear relatively dark. This hypothesis also accounts for the observed wind direction in the Southern Hemisphere because it implies that the equatorial regions are warmer than the south polar regions.
Preliminary scientific findings of the Ulysses mission that was launched in October 1990 and arrived at Jupiter in Februrary 1992 are reviewed. The mission was aimed at using the gravity field of Jupiter to redirect the spacecraft to the sun's polar regions, which will be traversed in 1994 and 1995. Major results include possible entry into the polar cap; the identification of magnetospheric ions originating from Jupiter's ionsphere; Io, and the solar wind; observation of longitudinal asymmetries in density and discrete wave-emitting regions of the Io plasma torus; the presence of counter-streaming ions and electrons, field-aligned currents, and energetic electron and radio bursts in the dusk sector on high-latitude magnetic field lines; and the identification of the magnetic field direction in the dusk sector, which is indicative of tailward convection.
A description of the sea surface height variabilities during 1986-1988 in the tropical Pacific Ocean is presented on the basis of Geosat altimeter data and a tropical Pacific Ocean GCM (OGCM) forced with observed winds from Florida State University. Both data sets are validated against in situ sea-level measurements at 12 selected sea-level stations in the equatorial Pacific and were found to be in good agreement with these measurements with correlation coefficients of 0.69 for Geosat and 0.71 for OGCM. The Geosat altimeter data are capable of describing sea surface height variabilities during 1986-1988 in the tropical Pacific, in particular, the seasonal cycle, the 1987 El Nino and 1988 La Nina episodes, and the December 1986 equatorial Kelvin wave event. The OGCM-simulated surface dynamic height is found to be sensitive to different surface wind products.
The total amount of water that precipitates on large continental regions is supplied by two mechanisms: 1) advection from the surrounding areas external to the region and 2) evaporation and transpiration from the land surface within the region. The latter supply mechanism is tantamount to the recycling of precipitation over the continental area. The degree to which regional precipitation is supplied by recycled moisture is a potentially significant climate feedback mechanism and land surface-atmosphere interaction, which may contribute to the persistence and intensification of droughts. Gridded data on observed wind and humidity in the global atmosphere are used to determine the convergence of atmospheric water vapor over continental regions. A simplified model of the atmospheric moisture over continents and simultaneous estimates of regional precipitation are employed to estimate, for several large continental regions, the fraction of precipitation that is locally derived. The results indicate that the contribution of regional evaporation to regional precipitation varies substantially with location and season. For the regions studied, the ratio of locally contributed to total monthly precipitation generally lies between 0. 10 and 0.30 but is as high as 0.40 in several cases.