Showing papers on "Haze published in 1973"

Matrix operator theory of radiative transfer. 2: scattering from maritime haze

Abstract: Matrix operator theory is used to calculate the reflected and transmitted radiance of photons that have interacted with plane-parallel maritime haze layers. The results are presented for three solar zenith angles, three values of the surface albedo, and a range of optical thicknesses from very thin to very thick. The diffuse flux at the lower boundary and the cloud albedo are tabulated. The forward peak and other features in the single scattered phase function cause the radiance in many cases to be very different from that for Rayleigh scattering. In particular the variation of the radiance with both the zenith or nadir angle and the azimuthal angle is more marked and the relative limb darkening under very thick layers is greater for haze M than for Rayleigh scattering. The downward diffuse flux at the lower boundary for A = 0 is always greater and the cloud albedo is always less for haze M than for Rayleigh layers.

Venus: Composition and Structure of the Visible Clouds

Abstract: It is proposed that the visible cloud deck on Venus is composed of droplets of sulfuric acid. These are formed by the very rapid photooxidation of carbonyl sulfide in the upper atmosphere. The clouds are best described as an extensive haze since the predicted particulate scale height probably exceeds the gas scale height within the layer. The predicted mixing ratio for water is .000001 (lower limit), and for both carbonyl sulfide and sulfur dioxide it is .0000001 (upper limit); these are in good agreement with observations. Gaps in the layer are not possible unless the planetary scale dynamics produce cloud turnover times of less than a few days. Under these conditions, the water mixing ratio could approach .0001, and the formation of a thin hydrochloric acid haze at high altitude above the main cloud is possible.

Long-Range Transport of Air Pollution: A Case Study, August 1970

Abstract: An air pollution episode during August 1970 over the central United States is examined. By use of surface visibilities and an 850-mb wind trajectory analysis, we observed the pollution to advance as much as 700 mi from the central midwest (source region) into the upper midwest and Great Plains (impact area). A large, nearly stationary high-pressure system over the source region allowed the pollution to accumulate beneath a mid-level subsidence inversion located generally near 700 mb. Southeasterly flow around the backside of the High and the northeasterly flow around a weak Low to the south advected the pollution into the impact area. At times, surface visibilities in parts of the impact area were restricted by haze to as little as 4 mi. Although particulate count data were meager, several stations recorded their highest particulate count of the year during the episode.

Secular increases in summer haziness in the Atlantic provinces

Abstract: Since 1953, there has been a significant increase in the number of hours (May to October) of reported haze, smoke and/or dust at synoptic observing stations in the Atlantic Provinces and Eastern Quebec. Because the increase is associated mainly with south to southwest winds, and because there has in fact been a decrease in particulate emissions in eastern North America during this period, the suggestion is made that the increase in haziness is due to increasing photochemical activity, resulting from greater emissions of gases such as SO2 and NOx from sources along the United States eastern seaboard.

Ozone trend and haze scattering

Abstract: Direct sun observations made with Dobson spectrophotometers at Darwin, Brisbane, Aspendale and Macquarie Island in Australia are used to assess the changing character of haze in the atmosphere using (XAD — XA) values which represent the large particle (larger than air molecules) scattering. It has been observed that at Darwin and Brisbane (XAD — XA) decreases from 1960 to 1970 implying that the smaller size particles are increasing in number in relation to larger size particles. An assessment of the error in the calculation of ozone by this gradual change of haze scattering in the last decade has been made. It is estimated that about 53 per cent of the observed change in XAD value at Brisbane is possibly due to changing haze pattern.

The aureole of a star image

Abstract: Telescope star-image profiles for various observing conditions are compared. Effects of mirror realuminization, secondary support diffraction spikes, and atmospheric haze are shown. A modification to the previously found inverse-square aureole is discussed. Key words: star image profile

Oil-impregnated capacitor

Abstract: An oil-impregnated capacitor has a plastic dielectric with a haze value greater than 20%. The haze results in a higher CSV and breakdown voltage. The plastic can also be roughened.

Inference of total ozone from photometric measurements of sky radiation

Abstract: Ground-based photometric measurements of spectral sky radiation have been made using a simple filter instrument Sky radiation intensities measured in the solar vertical at 3200 and 3600 A are compared to infer total ozone A model of a multiple scattering Rayleigh atmosphere serves as a primary reduction parameter Spectral measurements of all-sky radiance distribution are used to study the effects of haze and clouds on the inference of total ozone The brightness distribution of clear and overcast sky in ultraviolet is also described

Aerocolloid formation from semisolid materials exposed to sunlight.

Abstract: Substances heretofore little considered, to these investigators' knowledge, may contribute significantly to urban atmospheric haze because they are exposed in great quantities to sunlight.

A field investigation and numerical simulation of coastal fog

Abstract: A field investigation of the microphysical and micrometeorological features of fogs occurring near Los Angeles and Vandenberg, California was conducted. Observations of wind speed and direction, temperature, dew point, vertical wind velocity, dew deposition, drop-size distribution, liquid water content, and haze and cloud nucleus concentration were obtained. These observations were initiated in late evening prior to fog formation and continued until the time of dissipation in both advection and radiation fogs. Data were also acquired in one valley fog and several dense haze situations. The behavior of these parameters prior to and during fog are discussed in detail. A two-dimensional numerical model was developed to investigate the formation and dissipation of advection fogs under the influence of horizontal variations in surface temperature. The model predicts the evolution of potential temperature, water vapor content, and liquid water content in a vertical plane as determined by vertical turbulent transfer and horizontal advection. Results are discussed from preliminary numerical experiments on the formation of warm-air advection fog and dissipation by natural and artificial heating from the surface.

Study to demonstrate the feasibility of and determine the optimum method of remote haze monitoring by satellite

Abstract: The author has identified the following significant results. Ground truth data has been obtained in order to determine the amount of haze present at the time of ERTS-1 passes over the Los Angeles area. October 21, 1972 was the haziest day, that was essentially cloud free, to date. At the time of the next pass, November 8, 1972 this area was quite clear. Changes in terrain features are minimized because these were consecutive passes. Digital tapes of the ERTS-1 data from these two days are being analyzed to determine the effects of haze on the data, in order to determine the optimum method for monitoring haze from a satellite. Preliminary results indicate that a slight reduction in contrast and some distortion of spectral signatures are caused by heavy haze. This effect is thought to be sufficient to determine the presence of moderate haze without the benefit of ground truth data. It is significant to note that there is very little degradation of ERTS-1 data caused be a rather heavy haze. For many purposes the data obtained on a hazy day are just as useful as that obtained on a clear day.