LIMS Instrument Package (LIP) balloon experiment: Nimbus 7 satellite correlative temperature, ozone, water vapor, and nitric acid measurements

The Limb Infrared Monitor of the Stratosphere (LIMS) LIP balloon experiment was used to obtain correlative temperature, ozone, water vapor, and nitric acid data at altitudes between 10 and 36 kilometers. The performance of the LIMS sensor flown on the Nimbus 7 Satellite was assessed. The LIP consists of the modified electrochemical concentration cell ozonesonde, the ultraviolet absorption photometric of ozone, the water vapor infrared radiometer sonde, the chemical absorption filter instrument for nitric acid vapor, and the infrared radiometer for nitric acid vapor. The limb instrument package (LIP), its correlative sensors, and the resulting data obtained from an engineering and four correlative flights are described

Ice nucleation processes in upper tropospheric wave-clouds observed during SUCCESS

We have compared in situ measurements near the leading-edges of wave-clouds observed during the SUCCESS experiment with numerical simulations. Observations of high supersaturations with respect to ice (> 50%) near the leading edge of a very cold wave cloud (T < -60°C) are approximately consistent with recent theoretical and laboratory studies suggesting that large supersaturations are required to homogeneously freeze sulfate aerosols. Also, the peak ice crystal number densities observed in this cloud (about 4 cm¯³) are consistent with the number densities calculated in our model. In the warmer wave-cloud (T ~ -37°C) relatively large ice number densities were observed (20-40 cm¯³). Our model calculations suggest that these large number densities are probably caused by activation of sulfate aerosols into liquid droplets followed by subsequent homogeneous freezing. If moderate numbers of effective heterogeneous freezing nuclei (0.5-1cm¯³) had been present in either of these clouds, then the number densities of ice crystals and the peak relative humidities should have been lower than the observed values

Environmental conditions required for contrail formation and persistance

The ambient temperatures and humidities required for contrail formation and persistence are determined from in situ measurements during the Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) experiment. Ambient temperatures and water vapor concentrations were measured with the meteorological measurement system, a laser hygrometer, and a cryogenic hygrometer (all onboard the DC-8). The threshold temperatures are compared with theoretical estimates based on simple models of plume evolution. Observed contrail onset temperatures for contrail formation are shown to be 0-2 K below the liquid-saturation threshold temperature, implying that saturation with respect to liquid water must be reached at some point in the plume evolution. Visible contrails observed during SUCCESS persisted longer than a few minutes only when substantial ambient supersaturations with respect to ice existed over large regions. On some occasions, contrails formed at relatively high temperatures (> -50°C) due to very high ambient supersaturations with respect to ice (of the order of 150%). These warm contrails usually formed in the presence of diffuse cirrus. Water vapor from sublimated ice crystals that entered the engine was probably necessary for contrail formation in some of these cases. At temperatures above about -50°C, contrails can only form if the ambient air is supersaturated with respect to ice, so these contrails should persist and grow.Copyrighted by American Geophysical Union

Uptake of NOy on wave-cloud ice particles

In flight through a wave cloud during SUCCESS on 2 May 1996, simultaneous forward- and aft- facing NOy inlets were used to infer the amount of condensed-phase NOy present on ice particles that were up to a few minutes old. Condensed-phased amounts were 25-75 pptv, or 10-20% of gas-phase NOy. Given the rapid HNO₃ uptake on ice observed in the laboratory, a model calculation implies that virtually all of the gas-phase HNO₃ will be depleted in the first 1-2 minutes after the appearance of ice. Thus the NOy observations are consistent with the laboratory results only of the ambient HNO₃/NOy ratio is 10-20%.Copyright 1998 by the American Geophysical Union

Prevalence of ice-supersaturated regions in the upper troposphere : implications for optically thin ice cloud formation

In situ measurements of water vapor and temperature from recent aircraft campaigns have provided evidence that the upper troposphere is frequently supersaturated with respect to ice. The peak relative humidities with respect to ice (RHI) occasionally approached water saturation at temperatures ranging from -40°C to -70°C in each of the campaigns. The occurrence frequency of ice supersaturation ranged from about 20% to 45%. Even on flight segments when no ice crystals were detected, ice supersaturation was measured about 5-20% of the time. A numerical cloud model is used to simulate the formation of optically thin, low ice number density cirrus clouds in these supersaturated regions. The potential for scavenging of ice nuclei (IN) by these clouds is evaluated. The simulations suggest that if less than about 5 x 10¯³ to 2 x 10¯² cm¯³ ice nuclei are present when these supersaturations are generated, then the cirrus formed should be subvisible. These low ice number density clouds scavenge the IN from the supersaturated layer, but the crystals sediment out too rapidly to prevent buildup of high supersaturations. If higher numbers of' ice nuclei are present, then the clouds that form are visible and deposition growth of the ice crystals reduces the RHI down to near 100%. Even if no ice clouds form increasing the RHI from 100% to 150% between 10 and 10.5 km results in a decrease in outgoing longwave radiative flux at the top of the atmosphere of about 8 W m¯². If 0.02-0.1 cm¯³ IN are present, the resulting cloud radiative forcing reduces the net radiative flux several watts per square meter further. Given the high frequency of supersaturated regions without optically thick clouds in the upper troposphere, there is a potential for a climatically important class of optically thin cirrus with relatively low ice crystal number densities. The optical properties of these clouds will depend very strongly on the abundance of ice nuclei in the upper troposphere

United States Bureau of Mines Bulletin 312

From Introduction: "This report presents the results of an investigation of the physical properties and characteristics of bauxite, with special reference to the possibility of applying commercial methods of concentration to low-grade bauxite.

United States Bureau of Mines Bulletin 5159

Report issued by the Bureau of Mines over investigations of coking coal reserves of Marion County, Tennessee. Testing to determine suitability for producing metallurgical coke is also presented. This report includes tables, maps, and illustrations

United States Bureau of Mines Bulletin 278

From Introduction: "The Birmingham district holds large deposits of red hematite, coal, and flux extends from Springville on the northeast to below on the southwest. The work was begun in July, 1923, and ores from a number of points within the Birmingham district have since been studied. A method of magnetic concentration has been investigated which, it is believed, will successfully remove a large part of the gangue and incur only a small loss of iron