Atmosphere wind speed averages

It should be emphasized that Figure 3.5 presents the mean zonal wind, that is, the wind speed averaged over longitude and time. In addition, local variations in the wind speed and direction are observed. These dynamical disturbances are associated with the presence of atmospheric waves (see Section 3.4). The propagation of these waves through the atmospheric medium is determined by the basic state of the atmospheric fluid at the same time, the dissipation of the waves tends to modify the basic state itself. Beside radiatively forced seasonal variations,... 

Introduction Gas dispersion (or vapor dispersion) is used to determine the consequences of a release of a toxic or flammable material. Typically, the calculations provide an estimate of the area affected and the average vapor concentrations expected. In order to make this determination, one must know the release rate of the gas (or the total quantity released) and the atmospheric conditions (wind speed, time of day, cloud cover). 

Atmospheric Conditions - Normal average wind speed, ambient air temperature, air density, relative humidity. 

The weather data are based on thousands of observations of wind speed, wind direction and atmospheric stability taken over the desired averaging interval at local weather bureau stations. 

The deposition velocities depend on the size distribution of the particulate matter, on the frequency of occurrence and intensity of precipitation, the chemical composition of the particles, the wind speed, nature of the surface, etc. Typical values of and dj for particles below about 1 average residence time in the atmosphere for such particles is a few days. 

The degree of meteorological data required for performing the analysis depends on the accuracy of the results desired. A single weather condition (combination of atmospheric stability and wind speed) can be used, however, it is usually impossible to isolate a single average condition that adequately represents all weather conditions. Many risk analyses use at least two weather conditions one stable (e.g., 2 m/s, stability F) and the other characteristic of average conditions (e.g., 5 m/s, stability D). 

The average particle size distributions for four predominantly crustal elements, Al, Si, Ca, and Ti, are shown in Figure 3. They are essentially identical. It should be pointed out that the downturn of the relative concentrations above 8 ymad (impactor stage 6) is the combined result of the actual distribution of particle sizes in the atmosphere and the efficiency with which these very coarse particles can enter (upward) into the cascade impactor. This efficiency must decrease with increasing particle size and generally depend on inlet design and wind speed. Nevertheless, it is important to note here that the patterns of the four elements are similar, implying a common aerosol source. 

Earths climate is different than Earths weather. Weather includes those atmospheric conditions that change from hour to hour or day to day, such as temperature, rain, wind speed, or cloud cover. Climate, on the other hand, is weather over time, the long-term patterns or trends in worldwide temperature, rain, and cloud cover, among other conditions. It is a worldwide look at weather averaged over thousands of years. 

The information on the quantities of combusted materials, and on aerosol and elemental carbon production, which is collected in Tables II-V, has been combined in Table VI to derive the state of the atmosphere during the nuclear war. We assume that the war would last for only a few days the aerosol particles would also be given off to the atmosphere in such a short time. Most fire produced aerosol would initially be located between 30°N and 60 N, where most of the nuclear targets are located. If the nuclear explosions would occur over a period of three days, the fire plumes produced on the West and East coast of the US and over Europe (including the USSR) could cover most of the 30-60°N latitude belt, except the Pacific Ocean. This is based on an average westerly wind speed of 20 m/s in tbe middle and upper troposphere (Oort and Rasmussen, 1971). Spread in South-North direction within the latitude zone should... 

One commonly used suite of models that is based on Gaussian plume modeling is the Industrial Source Complex (ISC) Dispersion Models (US EPA, 1995). This suite includes both a short-term model (ISCST), which calculates the hourly air pollutant concentrations in an area surrounding a source, as well as a long-term model (ISCLT), which calculates the average air pollutant concentrations over a year or longer. ISCLT uses meteorological data summarized by frequency for 16 radial sectors (22.5° each) this data format is referred to as a stability array (STAR). Within each sector of STAR, joint frequencies of wind direction, wind speed, and atmospheric stability class are provided. 

More recent investigations on the mean atmospheric circulation patterns have shown that there are typical circulation patterns that trigger MBls and are necessary for their occurrence (Matthaus and Schinke, 1994). One of the basic conditions linked to major events is, on average, a mean continuous increase in wind speed from westerly directions over several weeks as, for instance, very distinctly observed in 1951 (Wyrtki, 1954) and 1993 (Matthaus and Lass, 1995). This increase begins about 2 weeks before the main inflow period and reaches maximum values on the day before the overflow of water with salinities >17 psu across the Darss Sill. The higher the mean wind speed and its duration during the main inflow period, the stronger the inflow. 

This problem is a first-order attempt to quantify the possible anthropogenic perturbation of the northern hemisphere (NH) marine sulfur cycle. First, assume that present-day anthropogenic sulfur emissions result in 20 Tg S/year being transported from North America to the atmosphere over the NH Atlantic and 10 Tg S/year being transported from Asia to the atmosphere over the NH Pacific. Assume a uniform concentration in the N-S direction, average westerly wind speeds... 

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