M.S. - Meteorology
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Item The relationship between the persistent winter cloud zone and the jet stream in the tropical Southwest Pacific(University of Hawaii at Manoa, 1971) Osborn, Hayward A. L.; MeteorologyThe strength of the sub-tropical jet stream in the south-west Pacific has been rather a mystery. By performing a scale-analysis of the equations of motion simplified equations for synoptic scale motions in the tropics are derived. This allows the determination of vertical velocity, and thus a study of the kinetic energy processes can be made. For the case considered it is found that there is kinetic energy generation within a cloud zone to the north of the jet stream. This energy is transported aloft and southwards towards the jet stream. It is suggested that such a process is partially responsible for the maintenance of the jet stream.Item The sequence of meteorological events at Canton Island during the 1972-1973 El Niño cycle(University of Hawaii at Manoa, 1975) Morris, Victor Franklin.; MeteorologyThis study analyzes meteorological conditions at Canton Island during the 1972-1973 El Nino Cycle. Heavy rains first appeared in April 1972, and monthly totals exceeded nine inches or more from October 1972 to March 1973. Conditions returned to normal inItem A study of Hawaiian and Line Islands rainfall(University of Hawaii at Manoa, 1976) Meisner, Bernard N.; MeteorologyThis report can be considered as yet another installment in what will probably be a never-ending study of precipitation in the vicinity of the Hawaiian and Line Islands. It began as an attempt to update an excellent study conducted by Solot (1950). AlthouItem Synoptic regimes associated with recent floods in the Rewa(University of Hawaii at Manoa, 1976) Krishna, Ram.; MeteorologyThe relevance of flooding in the Rewa River Basin to the economy of Fiji is reflected in the two recent, Government-initiated, predominantly hydrological investigations relating to the Basin. Identification of synoptic patterns and related satellite obserItem A technique for estimating tropical open ocean rainfall from satellite observations(University of Hawaii at Manoa, 1974) Kilonsky, Bernard John.; MeteorologyThe purpose of the study was to obtain accurate estimates of tropical open ocean rainfall from satellite observations. The approach used was the development of a procedure for extracting (approximately one month of data per person per week) highly reflectItem Cross-equatorial interactions in the development of a winter typhoon: Nancy 1970(University of Hawaii at Manoa, 1974) Guard, Charles P.; MeteorologyThe purpose of this study is to examine the formation and development of a winter typhoon (Typhoon Nancy: February 1970) and to determine whether significant differences exist between her formation and development and that of "seasonal" typhoons. ParticulItem A Radar-Based Climatology of Thunderstorms in Hawai‘i(University of Hawaii at Manoa, 2018-08) Ballard, Robert A.; MeteorologyWhile relatively infrequent, hazards related to severe convection in Hawai‘i do occasionally occur. Our understanding of these events can be improved by using algorithm data from the Weather Surveillance Radar-1988 Doppler (WSR-88D) to help build a spatial, temporal, and intensity climatology which eliminates population density and diurnal sampling biases. Radar can also expand the climatological area by approximately 17 times over that offered by land-based reports only. Surface and upper air observations and storm reports are used to validate the radar algorithm output. Parameters and indices from sounding data at Līhu‘e are compared to observed thunderstorms, as well as to output from the Maximum Estimated Hail Size (MEHS) and Tornado Vortex Signature (TVS) algorithms, to establish values significant for the occurrence of these events. The data show that greater instability is typically needed to support thunderstorms in Hawai‘i, approximately double that found for similar events over the continental United States. MEHS values greater than 32 mm appear to indicate a higher risk of severe hail in Hawai‘i, and these occur within radar range on average every 5.5 days per year. MEHS values likely to be associated with supercells and very large hail occur within radar range about 1.5 day per year. Most TVSs in Hawai‘i are associated with delta-V values of <30 m s-1, but values ≥ 45 m s-1 (known to be associated with strong tornadoes) have been observed. The results presented here should help forecasters to better evaluate the risk of these rare but important events.Item A Bioinformatics Approach to Finding Transcriptional Regulatory Motifs in Bacteria(University of Hawaii at Manoa, 2016-05) Takebayashi, TarynDifferential RNA sequencing has made it possible to determine the transcription start sites (TSS) for many of the genes in a genome. By using the TSS information, this study aimed to take advantage of the relatively simple transcriptional organization in bacteria and determine potential transcription factor binding sites for the cyanobacterium Anabaena sp. PCC 7120. By revealing shared sequences adjacent to known TSS, shared TFBS and unique TFBS were identified. This may make this set of computer applications useful in determining which genes in a given dataset are possibly transcriptionally coregulated. This project made use of the transcriptional map of the cyanobacterium Anabaena sp. PCC 7120 in order to narrow down the areas of the bacterial genome that may contain TFBS. The utilization of transcription start sites in locating TFBS is an additional unique feature of this study. This study culminated in tutorials (as shown in the Appendices) covering the programming involved in this project that may help biology students to begin writing their own computer programs.Item Large-Scale Weather Patterns Favorable for Vog Occurrences on Oahu, Hawaii(University of Hawaii at Manoa, 2015-12) Tofte, KristineKilauea Volcano is one of the most active volcanoes in the world, and its two vents (Halemaumau and Puu Oo) release more sulfur dioxide (SO2) than major power plants. During the time of this study (April 2009 – December 2014), the two vents released approximately 3,700 tons of SO2 per day. Within the atmosphere, the SO2 is oxidized and converted to sulfuric acid aerosols through reactions with OH radicals and H2O molecules in clear sky and cloud reactions. This sulfuric aerosol is commonly referred to as volcanic smog (vog) in Hawai'i. During prevailing trade winds conditions, the vog emitted from Kilauea volcano is advected towards the southwest of the Big Island of Hawai'i. However, when winds shift to a southeast or southwest direction, then vog can be carried up the island chain affecting all the Hawaiian Islands. This study focuses on the largescale Weather patterns that cause this wind shift and specifically, on conditions that bring the vog to the island of Oahu, the most heavily populated island. In order to identify large-scale weather patterns that bring vog to Oahu, two datasets were used. Firstly, the Hawai'i Department of Health maintains a record of hourly aerosol mass concentrations in size ranges below 10 μm (PM10) and below 2.5 μm (PM2.5). The volcanic plume consists of accumulation mode sulfuric acid aerosols below 1μm in diameter and therefore, the PM2.5 measurements will capture information about vog concentrations. As part of this study, Hawai'i Department of Health PM2.5 measurements were used to identify elevated vog conditions. Secondly, European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis data were used to determine weather patterns occurring prior and during Oahu vog events. As part of this effort, the ERA-Interim reanalysis data, for different weather patterns, were downscaled to a resolution of 3.3 km using the Weather Research and Forecasting (WRF) model. The WRF output was run in the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to produce both trajectory and concentration plots. The HYSPLIT model allowed for a visual representation of how the vog plume follows the large-scale wind patterns. Data from April 2009 throughout 2014 were analyzed and the total number of vog days was found to be 101. These 101 vog days were the result of 57 distinct vog events lasting from hours up to four days. The 57 events were further categorized into three large-scale weather patterns: precold fronts (37 cases), upper-level disturbances (17 cases) and Kona lows (3 cases). The pre-cold front events had variable duration lasting up to four days and it was found that the largest vog concentrations (PM2.5 values) occurred during long duration pre-cold front events.Item Conditions Favorable for the Occurrence of Trapped Mountain Lee Waves Downstream of O‘ahu(University of Hawaii at Manoa, 2015-05) Li, LiyeThe purpose of this study is to determine the synoptic conditions necessary for trapped lee wave development over Oʻahu. The study also shows that the high-resolution mesoscale numerical models could possibly provide valuable numerical guidance for the onset, development and dissipation of trapped lee wave events in Hawaiʻi. The occurrence of trapped lee wave clouds is possible in Hawaiʻi, especially downstream of the island of Oʻahu. The Koʻolau and Waiʻanae mountain ranges of Oʻahu are oriented NW-SE. The pre-frontal southwesterly wind in winter has a large wind component perpendicular to these mountain ranges. With the presence of an inversion aloft, trapped lee waves may occur during the wintertime. In the summer time, northeast trade wind is persistent and trapped lee wave event is relatively rare. In this study, environmental conditions related to the development of three trapped lee wave events (27 January, 2010—TRAP1; 24 January—TRAP2, 2003; 26 January, 2014—TRAP3, 25 August, 1977) are analyzed using soundings, charts, satellite images. The available model input datasets for the summer case in 25 August, 1977 is ERA-40 in the resolution of 2.5⁰×2.5⁰, which is not enough to simulate high-resolution model in 1-km. With input analysis datasets in the resolution of 1.25⁰×1.25⁰, the three wintertime events are successfully predicted by the high-resolution WRF model. Among them, TRAP1 and TRAP2 are initialized using the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR), and TRAP3 is initialized with NCEP Climate Forecast System Version 2 (CFSv2) output.Results from a WRF model simulation with a horizontal 1-km grid indicate that the trapped lee waves are most significant just beneath the inversion. There are several common factors involved in the occurrence of these trapped mountain wave events: 1) the presence of a well-defined inversion above the ridge tops; 2) abundant low-level moisture; 3) strong low-level winds with Froude Number (Fr) > 1 impinging on the mountain ranges; and (4) wind shear with increasing wind speed with respect to height through the inversion. A strong pre-frontal southwesterly flow is the typical synoptic setting for the occurrence of trapped mountain waves in winter, whereas in the summer months the presence of an upper-level disturbance with easterly winds aloft is a necessary prerequisite. The vertical wind profile is the key element to determine whether trapped lee waves or downslope winds form. None of the trapped lee wave events in winter or summer have a critical level. If a critical level exists between 500 hPa to 300 hPa, and wind decreases with height in the low level, a downslope wind storm or mountain wave may occur instead of trapped lee waves. Sensitivity tests for the 27 January, 2010 case are performed with reduced relative humidity (RH). With lower RH, trapped lee waves have smaller amplitudes and shorter wavelengths suggesting a latent heat release feedback to the environmental flow.