Thesis and Dissertations

Investigating Troposphere Lower Stratosphere Dynamics over Tropical and Subtropical Region Using Ground Based and Satellite Data

2025-04-23T05:59:04Z

Investigating Troposphere Lower Stratosphere Dynamics over Tropical and Subtropical Region Using Ground Based and Satellite Data Negash, Tsehaye This dissertation investigates the complicated troposphere-lower stratosphere (TLS) region, with an emphasis on trace gas transport across the tropical tropopause and how it a ects climate and weather systems. There is a paucity of extensive research on the spatial and temporal variations of TLS temperature over tropical Ethiopia and subtropical Egypt using numerous data sources, despite earlier research on natural inuences. This study analyzes long-term trends in TLS temperature from 2006 to 2020 by utilizing both ground-based and COSMIC satellite data, focusing on TLS variability and its inuencing drivers through wavelet analysis and multivariate linear regression methods. It also examines Kelvin wave patterns observed from 2019 to 2020 using Radiosonde and AIRS satellite datasets, along with the exchange of trace gases ozone and water vapor in the UTLS region. Our study demonstrates that the tropopause height decreases from the tropics to the subtropics with a slight increase in temperature. The tropical station Addis is located at 17 km and has a temperature of 190-194 K, while the subtropical Cairo is located at 15 km and has a temperature of 201 K. Morlet wavelet analysis applied to cold point tropopause temperature (CPTt) exhibits AO and cold point tropopause height (CPTh) exposes QBO-like signal patterns. An investigation of the response to natural drivers such as ENSO, SF, QBO, IOD, and aerosols on temperature variability reveals positive peaks at various altitudes. Lag analysis indicates delays in natural forcing e ects, revealing a warming trend in the tropospheric region and a cooling trend in the upper troposphere lower stratosphere (UTLS) region identi ed through multiple linear regression trend analysis. The tropical Addis station has the highest cooling rate of-0.38 K/decade at 12 km and the highest warming rate of 0.28 K/decade at 3 km, to the subtropical Cairo station, which has the highest warming rate of 0.38 K/decade at 2 km and the maximum cooling rate of-0.2 K/decade at 10 km. Further studies explore the activity of waves (KW), focusing on their distinctive features such as periodicity and wavelengths in tropical and subtropical regions. This analysis uses longitude-time and altitude-time data sourced from RS and AIRS satellite observations, covering the period from March 2019 to February 2020 in the TLS region. In Addis Ababa, KW periodicity ranges from 9.2 to 14.5 days with vertical wavelengths of 3.8 to 12.5 km, while in Cairo, it ranges from 6.4 to 13.3 days with vertical wavelengths of 6 to 11.2 km. KW shows downward propagation, especially summer, with maximum amplitudes of 8 K in Ethiopia and 4 K in Egypt. v This suggests that the KW exponentially decreases as it moves from the tropics to the subtropics. The study nds strong correlations between tropopause height and KW is 0.86 and gravity waves with tropopause height is 0.48. High KW activity is linked to low Outgoing Longwave Radiation (OLR) values, indicating signi cant convective activity during summer KW events. Our study further focuses on the roles of trace gases such as water vapor and ozone in the upper troposphere and lower stratosphere (UTLS), as well as their impact on climate change. Ozone distribution remains stable in the UTLS, except during spring in Ethiopia and autumn in Egypt. The transport of ozone and water vapor across the tropopause is controlled by the cold-point tropopause height (CPTh) and temperature (CPTt), respectively. In Egypt, the annual mean ozone volume mixing ratio (OVMR) ranges from 6 to 9 ppmv, while in Ethiopia, it ranges from 6 to 10 ppmv. Water vapor mixing ratio (WVMR) peaks at 600-400 ppmv in Ethiopia and 200-100 ppmv in Egypt. Egypt has a higher ozone mass ux (5 kg/s) compared to Ethiopia (3.4 kg/s), while Ethiopia has a higher water vapor mass ux (68 kg/s) compared to Egypt (30 kg/s). The study also identi es semi-annual oscillation (SAO) in WVMR and annual oscillation (AO) in OVMR in Ethiopia, and triannual oscillation (TAO) in WVMR and AO in OMR in Egypt.

Fathers’ Lived Experience in Raising Female Children With Intellectual Disability: the Case of Bahirdar City Adminstration.

2024-03-21T08:05:39Z

Fathers’ Lived Experience in Raising Female Children With Intellectual Disability: the Case of Bahirdar City Adminstration. Melaku, Serawork Intellectual disability is a disorder that begins with the onset of a child’s developmental period, from childhood to adolescence (American Psychiatric Association [APA], 2013). It includes both intellectual and adaptive functioning deficits in conceptual, social and practical domains (APA,2013). The main purpose of the study was to explore fathers lived experience in raising female children with intellectual disability, in Bahir Dar city administration. To do so, a qualitative phenomenological research design was utilized. The data was collected from fathers, mothers and siblings of female children with intellectual disability through semi-structured interview, focus group discussion and document analysis. Eight fathers, eight mothers and five siblings were selected by purposive sampling strategy from the total number of population. The collected data were analyzed following the qualitative data analysis procedures including; organizing, reading the transcribed data, coding, developing themes representing and reporting themes and finally interpreting meaning of findings. The finding reveals that, most fathers of female children with intellectual disability had low caregiving and raising experience of their female children with intellectual disability at home. As a result, not only fathers but also female children with intellectual disability face many challenges related with social isolation, stress, lack of income or finance, support problems and education, lack of responsibility and relationship problems and negative attitude. They also develop different overcoming solution to reduce challenges and problems by using various mechanisms; like planning, resilience and using various supports. Therefore, Government and nongovernmental organizations, rehabilitation centers, communities and all relevant stakeholders had to participate actively and collaboratively in support families to contribute and play significant role in raising female children with ID for better quality of life.

Assessment of Ramp Availability and its Associated Factors in Public Buildings in Bahirdar City Administration, Northwest Ethiopia

2024-03-21T07:55:08Z

Assessment of Ramp Availability and its Associated Factors in Public Buildings in Bahirdar City Administration, Northwest Ethiopia Yaregal, Yenework The main objective of this study was to assess ramp availability and its associated factors in Public Buildings in Bahir Dar City Administration.Institution based cross-sectional survey was conducted from March 14, 2023 to May 15, 2023 on126 study subjects (public institutions) using 95 % confidence interval, 50% proportion, margin of error 5% and non-response rate of 10%. The data was collected using self-administered questionnaire and observational check list. The collected data were cleaned, coded and entered into SPSS version 23 statistical software packages for analysis. A binary logistic regression was used. All variables were fitted in the bi-variable logistic regression and variables with p < 0.25 was used to select eligible variables for further multivariable logistic regression analysis. Adjusted odds ratios obtained from multivariable logistic regression analysis were used to identify the associated factors and variables with p< 0.05 was used to show a statistically significant associations. As the finding shows, a total of 116 institution mangers were participated and the response rate was with 92.1 %. The proportion of at least one ramp availability in public buildings was 62% (72/116) with low accessibility and adequacy rate of 20.7% (24/116) and 19.4 %( 14/72) respectively. Ramp availability was associated with construction building codes and guidelines (AOR= 8.00, p<0.003), Managerial decision (AOR= 5.47, p<0.006), Budget allocation (AOR=5.20, p<0.034) and Designers’ effort (AOR= 5.46, p<0.021). The p value should be written like I did. Inadequate ramps were observed in the public buildings. Ramp availability was associated with construction building codes and guidelines, Managerial decision, Budget allocation and Designers’ effort. Most of the public buildings are inaccessible due to absence of ramps. To alleviate the problem, every public institution should promote ramp construction and monitor its standard and adequacy in the public buildings.

Exploring the Challenges of Marriage among Persons with Disabilities in Wegera Wereda, Amhara Regional State, Ethiopia

2024-01-22T06:58:51Z

Exploring the Challenges of Marriage among Persons with Disabilities in Wegera Wereda, Amhara Regional State, Ethiopia Muhabaw, Tsedalu The main purpose of this study was to explore the challenges of marriage among persons with disabilities in Amhara Regional State, Wegera Wereda. The data was collected from persons with disabilities,their families and care givers through semi structured interview and focus group discussions. Fifteen persons with disabilities and ninefamily members and caregivers were selected by purposive sampling technique. Hence, as persons with visual impairment and and physical impairment meet the criterias of the researcher that those are aged to marry, eight persons with visual imparment and seven persons with visual imparets were selected. The collected data were analyzed by using thematic analysis techniques. In doing so, procedures including organizing, reading the transcribed data, coding, developing themes, representing and reporting themes, and finally interpreting meanings of findings were practiced. The findings of the study reveal that persons with disabilities face varieties of problems when they want to marry. Accordingly, economical, attitudinal, environmental and educational challenges were major challenges for persons with disabilities. In addition, the data shows that females were more challenged than males with disabilities because of poor expectation of communities and having high responsibilities of child rearing and other responsibilities at home. In order to overcome marriage related challenges, those persons with disabilities practiced their on coping mechanism like building good relationships with societies, accepting diversity and asking for support from families and others as any human beings seeks such support. The study finding implicates that community’s misunderstanding and low expectation towards persons with disabilities affects their participation in marriage. Therefore, the stake holders like social affairs and others such as experts in persons with special needs should give awareness raising trainings for communities and those persons with disabilities for the purpose of creating social inclusion and eliminating challenges to marriage of persons with disabilities.