A mathematical model for predicting coupled heat and water movement in unsaturated soil

An investigation was conducted to develop a comprehensive moisture model for predicting non-isothermal moisture conditions in soils. An extensive literature review indicated that a model based on the Philip and de Vries equations for non-isothermal moisture movement and heat conduction would give the best results. By using numerical methods, the implicit finite difference approximations to the moisture movement and heat-transfer equations were programmed for computer solution of water content and temperature in the soil with time. Validation studies indicate that the moisture model can be used to predict accurately moisture conditions in the soil. The model was validated by using hydraulic data from laboratory studies conducted on soil columns compacted with AASHO A-3 and AASHO A-4 soil. The application of the moisture model to the study of non-isothermal moisture movement in the field is demonstrated. The influence of parameters such as water table depth, precipitation, and soil hydraulic properties on soil moisture content are shown by use of the moisture model. The model is shown to be applicable to a wide range of boundary conditions and that it predicts the moisture-temperature regime with time in soils utilizing climatic input data.     

The orientation of the solar rotation axis from Doppler velocity observations

Mt. Wilson observations of solar velocity fields have been examined for evidence that the rotation axis of the nonmagnetic gas at the solar surface is oriented differently than the axis found by Carrington (1863) from sunspot observations. No difference is found with an accuracy of 0°.15 in the angle of inclination of the axis to the ecliptic.     

Fabry-Perot determinations of midlatitude F-region neutral winds and temperatures from 1975 to 1979

Fabry-Perot interferometer measurements of the Doppler shifts and widths of the nightglow 630.0 nm line at Laurel Ridge Observatory, Pennsylvania are presented for the period 1975 to 1979, covering both solar minimum and solar maximum conditions. The F-region neutral wind vectors v_n and temperatures T_n deduced from these measurements show both day-to-day changes and overall seasonal patterns in the nocturnal variations during geomagnetically quiet conditions. Divergence in both the meridional and zonal horizontal flow is noted on occasion. The v_n results are compared with models including only solar EUV heating and those with EUV plus a high latitude heat source. The aggregate v_n data for solar cycle minimum conditions agree best with model predictions for winter zonal and equinoctal meridional winds and worst for winter meridional and summer zonal winds. At solar cycle maximum the predicted, rapid transition at equinox from summer to winter wind patterns and vice-versa is observed. The T_n data are in reasonable agreement with the MSIS model predictions.     

A GEOGRAPHY OF RESEARCH-GRANT GETTING IN GEOGRAPHY

Geographers have become increasingly interested in who receives grants for basic research and why. Northeastern U.S. universities, and especially private universities in the Northeast, dominated those of all other regions in the number of proposals submitted to the Geography and Regional Science Program of the National Science Foundation as well as the number of funded projects and total awarded funds during the period 1979–1981. Successful grant applicants submitted proposals that demonstrated excellent potential to make a significant contribution towards improving the theoretical and methodological foundations of geography.     

The magnetic flux in the quiet sun network

The Ca ii K line emission from the quiet Sun network does not vary with the 11-year cycle (White and Livinston, 1981). We confirm this result from direct magnetic measurements. This effect is not simply explained by present empirical models of the evolution of surface magnetic fields.Now at Institute for Astronomy, University of Hawaii, Honolulu, Hawaii 96822, U.S.A.     

A measurement of the helium D3 profile with a birefringent filter

The D₃ line profile in plages on the disk is measured using a birefringent filter. The best fit Gaussian has a 1/e width of 0.4 Å, with negligible instrumental contribution. The D₃ opacity is produced in regions with thermal linewidth -0.1 Å; the much larger observed width indicates large non-thermal motions in the chromosphere.