Northern Wind Research Articles

Metamorphic Conditions of an Archean Core Complex in the Northern Wind River Range, Wyoming

Metamorphic Conditions of an Archean Core Complex in the Northern Wind River Range, Wyoming

Basin Analysis Aided by Remote-Sensing Data: Geologic Results in Wind River/Bighorn Basin Area, Wyoming: ABSTRACT

Aircraft and satellite remote-sensing data combined with surface and subsurface geologic and geophysical data have been used to investigate the formation and evolution of Laramide foreland basins in central Wyoming. Quaternary through Holocene geomorphology reveals post-Laramide basin excavation history. Six terrace/pediment surfaces have been recognized in the northern Wind River basin and have been correlated with equivalent surfaces in the Bull Lake and central Wind River basin areas, respectively. Permian through Eocene stratigraphic relationships distinguish late pre-Laramide through Laramide paleogeography. New type sections established in the eastern wind River basin/northern Casper arch area refine lithostratigraphic correlations with: (1) surface sections measured in the southern Bighorn basin and (2) subsurface sections on the southern Casper arch. Structural mapping in the southern Bighorn basin indicates predominantly compressional Laramide deformation. Numerous northeastward-dipping thrust faults that do not appear on published geologic maps have been recognized at the surface and have been confirmed with seismic data. Similar strategies of data acquisition and geologic analysis developed should be applicable in studies of similar foreland basins.

Post-Laramide Uplift and Erosional History of Northern Wind River Basin, Wyoming: ABSTRACT

Landsat Thematic Mapper (TM) multispectral scanner images together with aerial photographs have been used to infer Laramide to Holocene tectonic events along the northern fringe of Wind River basin near Wind River Canyon, Wyoming. TM images reveal the presence of a large system of alluvial fans, terraces, and residual tongue-shaped debris deposits covering an area of 90 mi2 at the base of Copper Mountain. The debris system contains predominantly dark metasedimentary clasts. Both Eocene (Wind River and Wagon Bed Formations) and Quaternary deposits are present, and some Eocene gravel has been reworked into the later units. These deposits contrast sharply in brightness and color with rocks in adjacent areas. Detailed topographic analysis of the terraces and fan remnants disclosed an episodic history of post-Wagon Bed (upper to middle Eocene) End_Page 245------------------------------ uplift and pediment cutting. At least 3 principal stages covering a vertical interval possibly as great as 1,300 ft have been identified. Soil profiles in Quaternary gravels capping the pediments show increase in maturity consistent with age inferred from topographic elevations. These local erosional stages may record tectonic events of regional significance. Their absolute ages need to be determined. End_of_Article - Last_Page 246------------

6300‐Å airglow meridional intensity gradients

Airglow meridional intensity gradients (MIG) that moved from east to west with the antisolar meridian have been observed during times of considerable magnetic activity. The magnitude of the gradient is around 0.1 R/km or more. We believe the MIG phenomenon develops as a result of a velocity gradient that is produced by the meeting of opposing meridional neutral winds. The northern wind system arises from the auroral heating at high latitude that produces meridional winds penetrating to low latitudes in the summer hemisphere. The southern wind system is produced by the equatorial midnight pressure bulge that is formed by the thermal tides of the lower atmosphere combined with the in situ forcing by EUV radiation absorption in the daytime. In a magnetic storm the merging of the two wind systems produces a sharp front over a latitudinal width of several hundred kilometers. North of the front the ionosphere is elevated, and the airglow is weak. South of the front the ionosphere is depressed, and the airglow is enhanced with a surface brightness of the order of 100 R. The conceptual model that evolved from these observations accounts for the overall behavior of the MIG as well as the normal midnight collapse. A simple calculation shows that the MIG can be used to estimate the meridional velocity gradient as well as the magnitude of the winds in the midnight pressure bulge.

Observational study of the interannual variability in certain features of the general circulation

Ten years of northern hemispheric upper air wind data have been applied to the study of year-to-year changes in certain statistics relating to the general circulation. This study focuses upon the yearly mean differential rotation of the atmosphere and the maintenance of its kinetic energy. In connection with the latter, fields of the mean meridional circulation have also been computed on a yearly basis. Some of the major findings are: (1) the range in the yearly values for the relative angular momentum of the whole atmosphere above the northern hemisphere is as large as 25%; (2) large interannual changes in the strength, location, and structure of the mean meridional cells are apparent; (3) the generation of zonal kinetic energy associated with the large-scale horizontal eddy convergence of momentum into the jet varies by as much as a factor of 2 or so in the sample of yearly values. However, the extent to which some of these changes may be associated with yearly changes in the observing station distribution or other sampling and analysis factors is not entirely known.

ON THE WATER TEMPERATURE AND THE CURRENT IN LAKE KIZAKI, NAGANO PREFECTURE, JAPAN

The authors have had limnological researches in Lake Kizaki several times since 1959 intending to make clear the movement of non-steady currents of such a small lake as Kizaki. They measured water temperature, direction and velocity of wind, and movement of “current drags” as an indicator of the movement of late currents. The water temperature was measured by a thermister-type thermometer, wind velocity by a Robinson's cup anemometer and water movement by several current drags kept at the depths of 1, 3, 5, 7, 10 and 15 meters. The authors inquired the distribution of water temperature at each depth as is shown Figs. 3-5, from which they presumed the water movement. Comparing this presumptive movement with that of current drags shown in Figs. 7-9, the following conclusions were reached: The northern and southern winds which are prevailing all the year round decide the movement of nonsteady current. In the summer season, the northern wind gives more remarkable influence on the currents than the southern wind does, not because of the difference of wind velocity but because of the topography around the lake. In the autumn, the partical circulation period, the movement of currents caused by wind is indistinctly recognized. The velocities of currents at the surface and the thermocline layer are low, while those of currents between the surface and the thermocline layers and below the thermocline layer are considerably high.

Meteorological Investigation in the Nursery (2)

In order to obtain the fundamental data about the available shelterhedges, we investigated the climatic factors, chiefly wind velocity and air temperature, near the hedges at Udagawa nursery of Tochigi Prefecture in October 1954. This hedges consisted of Hinoki were 3m high with a width of 1m and void ratio of the hedges was about 10%.The results of field measurements are as follows.(1) The wind velocity at the windward point on 5 times the hedge height reached 116% to the standard wind velocity at the leeward point on 16h (h=the hedge height). At leeward points on 2h, 4h and 8h, 0%, 29% and 55% respectively to the standard wind velocity. We found that the wind velocity was changed remarkably between the shelter-hedge and the leeward point about 4h.This trend was as same as that of evaporation.These measurements were done at 30cm high above ground surface.(2) As to air temperature at 30cm high above ground surface, if it blows the wind, the air temperature near the hedges was higher in the daytime and lower in the night-time than that of other place. But if it does not blow, there was not any difference everywhere.As to ground temperature, it was always high at leeward place near the hedges except the case of rainfall.Above mentioned results were obtained when it blew northern wind.