We analyze output from a domain-filling forward trajectory model in order to better understand the annual cycle of water vapor entering the stratosphere. To do this, we determine the minimum water vapor saturation mixing ratio along each trajectory (the final dehydration point or FDP) and assume that the parcel carries that much water vapor into the stratosphere. In the annual average, the tropical Western Pacific, equatorial Africa and South America, and Southeast Asia are found to be the locations of the most frequent FDPs. Looking at individual seasons, we find that FDPs in the tropical western Pacific tend to occur in the summer hemisphere, with FDPs over South America and Africa occurring predominantly during the boreal winter. During boreal summer, a dehydration maximum occurs in the Asian monsoon region. In the annual average, FDP maxima occur at 99 and 84 hPa. Looking at individual seasons, we find that FDPs occur at higher altitudes (centered at 84 hPa) during boreal winter and at lower altitudes (99 hPa) during boreal summer. The annual cycle in FDP altitude combines with the annual cycle in tropical tropopause layer temperatures to generate the observed annual variations in water vapor entering the stratosphere.

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The effect of increased stratospheric dust on the polarization and intensity of sunlight scattered by the terrestrial atmosphere in the spectral region near the ultraviolet transmission cutoff is examined. Particular interest is given to radiation reflected to space or transmitted to the surface in the direction perpendicular to the incident solar beam in a plane containing the sun and the local vertical. Theoretical results are presented from radiative transfer calculations using a simple single scattering model and a four layer model in which ground reflection and multiple scattering were treated. Results show that the polarization state of transmitted radiation of .2975 μ for an incident solar zenith angle of 70° is sensitive to dust loading above 50 mb. The depolarization caused by a moderate increase in stratospheric dust loading is found to be roughly comparable to that caused by ground reflection and tropospheric aerosol. The polarization of light reflected to space is found to be very sensitive to high altitude dust scattering while being much less sensitive to other sources of depolarization. Results show that increasing the amount of stratospheric dust can cause either an increase or a decrease in the daily dosage of ultraviolet radiation at the surface, depending on the altitude profile of the dust, the latitude and the season. Preliminary experimental results or polarization monitoring by a ground-based instrument are presented and discussed. Sky light polarization ratios in the direction normal to the solar beam at .2975 μ and .300 μ based on data collected in the spring and summer of 1980 from the roof of the Physics-Atmospheric Sciences building on the campus of The University of Arizona are presented and discussed. The stratospheric dust problem is considered in terms of stratospheric aerosol enhancement resulting from volcanic activity.

No description available.

Through the 21st century, global-mean stratospheric ozone abundances are projected to increase due to decreasing chlorine and bromine concentrations (as a consequence of the Montreal Protocol for Substances that Deplete the Ozone Layer), and continued CO₂-induced cooling of the stratosphere. Along with CO₂, anthropogenic emissions of the greenhouse gases N₂O and CH₄ are projected to increase, thus increasing their atmospheric concentrations. Consequently, reactive nitrogen species produced from N₂O and reactive hydrogen species produced from CH₄ are expected to play an increasingly important role in determining stratospheric ozone concentrations. Chemistry-climate model simulations were performed using the NIWA-SOCOL (National Institute of Water and Atmospheric Research - SOlar Climate Ozone Links) model, which tracks the contributions to ozone loss from a prescribed set of catalytic cycles, including the ozone-depleting nitrogen and hydrogen cycles, over latitude, longitude, pressure and time. The results provide a comprehensive picture of how stratospheric ozone may evolve through the 21st century under a range of greenhouse gas emissions scenarios, and quantitatively extend concepts that had previously been understood only qualitatively.

Thesis (Ph. D.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (p. [127]-142). Also available via the World Wide Web.

Thesis (M. Sc)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (p. 85-90). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 104-115).

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

This literature review analyses and discusses different theories and results regarding impact of volcanic eruptions on climate change in Earth's history. Present global warming has been attributed to anthropogenic emissions of greenhouse gases, mainly carbon dioxide, however changes in global temperatures have occurred before the onset of anthropogenic emissions. Certain prehistoric climate changes are thought to be caused by emissions of volcanic gases to the atmosphere. Many studies have investigated the connection between volcanic events and subsequent changes in global temperatures. A majority have concluded that volcanic sulfur dioxide is the main direct and indirect climate forcing gas influencing temperatures over time. Increased volcanic activity over the last 15 years is thought to be an inhibiting factor on present global warming. This is supported by evidence of past volcanic events preceding global cooling and warming periods during Holocene and prehistoric times. Further, there are indications that factors such as geographical position, season, gas composition, magnitude and duration of an eruption influences the extent of the climate forcing.Records of climate such as ice cores and tree growth rings and isotopic characterization have made it possible to identify volcano eruptions over time and determine the identity of the erupting volcano. Past and present data from these can be used to gain a better understanding of past climate changes as well as making predictions about future changes as a result volcanic eruptions. However, accuracy regarding temporal and spatial resolution of these records is of great importance for the validity of the results.