Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 157-165).

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 157-165). Also available in electronic version.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 140-146).

Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Guosheng Liu, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed June 8, 2006). Document formatted into pages; contains xi, 85 pages. Includes bibliographical references.

Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, September 2006. / Thesis Advisor(s): Tom Murphree, Rebecca Stone. "September 2006." Includes bibliographical references (p. 61-62). Also available in print.

Thesis (M.S.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology; and the Woods Hole Oceanographic Institution), 2006. / Bibliography: p. 75.

Thesis (M.Sc.)(Meteorology)--University of Pretoria, 2006. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

<p> Deep convection is an important component of atmospheric circulations that affects many aspects of weather and climate. Therefore, improved understanding and realistic simulations of deep convection are critical to both operational and climate forecasts. Large-eddy simulations (LESs) often are used with observations to enhance understanding of convective processes. This study develops and evaluates a nested-LES method using the Weather Research and Forecasting (WRF) model. Our goal is to evaluate the extent to which the WRF nested-LES approach is useful for studying deep convection during a real-world case. The method was applied on 2 September 2013, a day of continental convection having a robust set of ground and airborne data available for evaluation. A three domain mesoscale WRF simulation is run first. Then, the finest mesoscale output (1.35 km grid length) is used to separately drive nested-LES domains with grid lengths of 450 and 150 m. Results reveal that the nested-LES approach reasonably simulates a broad spectrum of observations, from reflectivity distributions to vertical velocity profiles, during the study period. However, reducing the grid spacing does not necessarily improve results for our case, with the 450 m simulation outperforming the 150 m version. We find that simulated updrafts in the 150 m simulation are too narrow to overcome the negative effects of entrainment, thereby generating convection that is weaker than observed. Increasing the sub-grid mixing length in the 150 m simulation leads to deeper, more realistic convection, but comes at the expense of delaying the onset of the convection. Overall, results show that both the 450 m and 150 m simulations are influenced considerably by the choice of sub-grid mixing length used in the LES turbulence closure. Finally, the simulations and observations are used to study the processes forcing strong midlevel cloud-edge downdrafts that were observed on 2 September. Results suggest that these downdrafts are forced by evaporative cooling due to mixing near cloud edge and by vertical perturbation pressure gradient forces acting to restore mass continuity around neighboring updrafts. We conclude that the WRF nested-LES approach provides an effective method for studying deep convection for our real-world case. The method can be used to provide insight into physical processes that are important to understanding observations. The WRF nested-LES approach could be adapted for other case studies in which high-resolution observations are available for validation.</p>

<p> Upper-tropospheric thermodynamic processes can play an important role in tropical cyclone (TC) structure and evolution. Despite its importance, until recently few <i>in-situ</i> observations were available in the upper levels of TCs. Two recent field campaigns&mdash;the National Aeronautics and Space Administration (NASA) Hurricane and Severe Storm Sentinel (HS3) and the Office of Naval Research Tropical Cyclone Intensity (TCI) experiment&mdash;provided a wealth of high-altitude observations within TCs. These observations revealed that the upper-level static stability and tropopause structure of TCs can change dramatically with both space and time. </p><p> The TCI dropsonde dataset collected during the rapid intensification (RI) of Hurricane Patricia (2015) revealed dramatic changes in tropopause height and temperature within the storm's inner core. These changes in tropopause structure were accompanied by a systematic decrease in tropopause-layer static stability over the eye. Outside of the eye, however, an initial decrease in static stability just above the tropopause was followed by an increase in static stability during the latter stages of RI. </p><p> Idealized simulations were conducted to examine the processes that might have been responsible for the tropopause variability observed in Hurricane Patricia. A static stability budget analysis revealed that three processes&mdash;differential advection, vertical gradients of radiative heating, and vertical gradients of turbulent mixing&mdash;can produce the observed variability. These results support the theoretical assumption that turbulent mixing plays a fundamental role in setting the upper-level potential temperature stratification in TCs. The existence of turbulence in the upper troposphere of TCs is corroborated by the presence of low-Richardson number layers in a large number of rawinsonde observations. These layers were more common in hurricanes than in weaker TCs, as hurricanes were characterized by both smaller static stability and larger vertical wind shear in the upper troposphere. </p><p> HS3 dropsondes deployed within and around TC Nadine (2012) observed two distinct upper-level stability maxima within the storm's cirrus canopy. Outside of the cirrus canopy, however, only one stability maximum was present in the upper levels. This maximum, just above the tropopause, was stronger over the cirrus canopy than outside of the cirrus canopy. Observations from a large rawinsonde dataset also show this structure, with a stronger temperature inversion located above the tropopause within regions of cold cirrus than outside of cold cirrus. It is hypothesized that vertical gradients of radiative heating, differential advection within the upper-tropospheric outflow layer, and vertical gradients of turbulence all could contribute to producing multiple stability maxima and the stronger temperature inversions in the lower stratosphere. </p><p>

This study identifies the spatial and temporal change of three types of Urban Heat Island (UHI). The Surface Urban Heat Island (SUHI) and Canopy Urban Heat Island (CUHI) are common UHI phenomena; however, the Radiant Urban Heat Island (RUHI) is proposed as a new type of UHI. Surface temperature, air temperature, and mean radiant temperature are used as indicators to measure the SUHI, CUHI, and RUHI respectively. Visual, statistical and microclimate approaches are carried out to increase the spatial and temporal resolution of the UHI modelling. The modelling approaches employ the integration of remote sensing, GIS, and ground measurements to improve the 2D and 3D representation of the UHI. Furthermore, the influencing parameters on the formation of the three types of UHI are investigated. The research aim is to produce an integrated approach that improves the low spatial or temporal coverage of UHI models in the literature. Moreover, it quantifies the causative parameters on the formation of UHI, and proposes mitigation strategies accordingly. London, Baghdad and Birmingham are the study areas of the SUHI, to test the variability of the size, population, Land Use/Cover (LULC), geometry, microclimate, geography, and level of development. Birmingham is chosen to study the CUHI and RUHI, because of the availability of the required data to model these UHIs. The SUHI is carried out between (2000- 2015) by the Land Surface Temperature (LST) of the thermal bands of Landsat, ASTER, MODIS and other auxiliary data. The CUHI, on the hand, is undertaken for two years (June 2012- June 2014) using high density air temperature measurements (HiTemp data), and the RUHI is simulated based on the mean radiant temperature (Tmrt) for four seasonal days that are part of the HiTemp. The integrated approach of the research employs three indictors (LST, air temperature, and Tmrt) to model the UHI which is unprecedented in the literature. Furthermore, within the use of each indicator there is a novel approach. The LST is acquired for three different cities using thermal bands from 1 m to 1000 m spatial resolution by employing diverse satellite and airborne images for about 15 years. The air temperature is hourly measured for two years by over 100 ground stations to produce high spatial and temporal thermal maps, and some of the ground stations are used to simulate the Tmrt. The Tmrt is used for the first time to model the UHI as a new indictor, which upgrades the 2D UHI using LST and air temperature to 3D UHI simulation. The influencing parameters on the formation of three types of UHI derived from the three indicators are identified, and they include many potential factors not investigated together in the literature. The findings of such topic might be useful for decision-makers when building new cities or modifying the existing ones, even the public can know more about their environment. The results show that, London and Birmingham core area usually work as SUHI during the day and night-time. However, Baghdad city exhibits low LST in the daytime except for high density residential area as well as indusial and commercial units. Similarly, Baghdad city becomes a SUHI in the night-time, and the water bodies have high LST during the cold nights for the three cities. Despite the higher diurnal, daytime and night-time LST of Baghdad compared to London and Birmingham, the London SUHI intensities were higher than those of Baghdad. The temporal change of the average LST and SUHI for Birmingham did not show significant change over the study period just like London; however, they both gave high spatial variability. The diurnal averages of SUHI are 9.41, 11.29, and 7.63 ºC for Baghdad, London, and Birmingham (during 2003-2015) respectively. The CUHI appear daytime and night-time in Birmingham urban and suburban areas throughout the different seasons for 56% of the total hours of two years, to reach 13.53 ºC. The simulation of Tmrt show the presence of daytime Radiant Urban Cool Island (RUCI) in the City Centre of Birmingham, while, the night-time induced the development of RUHI. Various influencing parameters contribute to the different types of UHI. The land cover types and anthropogenic heat are the main contributors to the SUHI. Fourteen controllable and uncontrollable predictors control the CUHI development. On the other hand, the radiation fluxes and shadow patterns direct the RUHI formation. Overall, the spatial and temporal behaviour of UHI varies for the different types of UHI. Each type of UHI is controlled by a set of causative parameters, and these might differ based on the type of UHI as well as where and when it occurs.