Browsing by Author "Allen Riordan, Committee Member"

Now showing 1 - 3 of 3

African American Perspectives: A Qualitative Study of an Informal Science Enrichment Program
(2007-08-12) Simpson, Jamila Rashida; Eileen Parsons, Committee Chair; Allen Riordan, Committee Member; Len Annetta, Committee Member; Glenda Carter, Committee Co-Chair
The Effects of Land-Atmosphere Interactions on Convection Initiation and Quantitative Precipitation Forecasts during the International H2O Project (IHOP_2002)
(2006-05-08) Qureshi, Aneela Laurel; Sethu Raman, Committee Co-Chair; Allen Riordan, Committee Member; Dev Niyogi, Committee Co-Chair
The International H₂O Project (IHOP_2002) was a field study conducted over the Southern Great Plains (SGP) during the summer of 2002. The main goal of IHOP_2002 was to study water vapor distribution in the atmosphere in order to improve predictions of warm season rainfall over the SGP. This research is aimed toward studying the effects of interactions between the land and atmosphere on mesoscale model simulations of convection and precipitation. The convection case examined during this study occurred from 17-20 June 2002 during IHOP_2002. A combination of synoptic forcing and surface features contributed to the development and continuance of convection during this time period. An observational analysis of this case showed evidence of surface dryline boundaries, accompanied by temperature and moisture gradients. Gradients of surface sensible and latent heat fluxes across the boundaries were also seen throughout the time period. Convection formed along the boundaries, suggesting that the land-surface features are important in the development of deep moist convection, even for cases with strong synoptic forcing. Two sets of sensitivity studies were conducted for this case using the MM5 model. The first involved testing the sensitivity of different surface data assimilation schemes on simulations of convection. A Control Simulation was performed using standard MM5 data assimilation, followed by an Experimental Simulation using a Flux-Adjusting Data Assimilation System (FASDAS). Significant differences were seen between these two simulations, especially in regards to accumulated precipitation. The Control Simulation generated very little precipitation, while the Experimental Simulation produced significantly more precipitation, and overall appeared to match more closely with observations than the Control. The Experimental Simulation also produced more varied heat flux fields, setting up strong gradients which may have led to the enhanced precipitation. The Experimental Simulation also overall matched observed heat fluxes than the Control Simulation. This study suggests that improvements in surface data assimilation may drastically improve predictions of convection and precipitation. The second study involved testing the effects of using two different coupled land-surface models (LSM) and planetary boundary layer (PBL) schemes on simulations of convection. The same convection case (17-20 June 2002) was used for this study. The first simulation used the Noah LSM coupled to the MRF PBL, and the second used the Pleim-Xiu (PX) LSM coupled to the ACM PBL. The precipitation fields generated by both simulations were very similar to each other; however they differed from the observations in terms of accumulations and timing. Significant differences were seen in the evolution of soil moisture and temperature between the two simulations, which was to be expected due to the different soil layers in each LSM used. There was a more immediate soil-precipitation feedback in the PX run, where the top soil layer was closer to the surface. A similar feedback could be seen in the heat flux fields. Results of this study provide evidence of the importance of the land-surface in mesoscale modeling, while also suggesting that improvements are needed in modeling land-surface processes.
Science Educators' Concerns Regarding Ethnic/Racial Diversity Issues in Science Education.
(2004-04-04) Simpson, Jamila Rashida; Glenda Carter, Committee Chair; Allen Riordan, Committee Member; John Park, Committee Member
The purpose of this study was to determine the concerns science educators have about ethnic/racial diversity issues in science education. Three groups of educators, preservice teachers (n=12), inservice teachers (n=15), and informal educators (n=14) participated in the study. Participants' concerns were determined by using the Multicultural Teaching Concerns Survey (MTCS) by Marshall (1996b) and by examining transcripts of group discussions. The MTCS results revealed that the science educators as a whole were most concerned about what strategies and techniques they should use with diverse students. The next area of greatest concern was 'Familial/Group Knowledge'. Finally, the areas of 'Cross-Cultural Competence' and 'School Bureaucracy' garnered similar levels of concern from science educators. Transcript data analysis revealed that the preservice science educators held two main concerns: a) Language as a barrier when communicating with ESL students, b) treating diverse students preferentially. Concerns were also more focused on 'self' as Fuller (1969) suggested occurs with preservice teachers. The inservice science educators were found to hold five major concerns: a) diverse students' home life, b) students dealing with diversity, c) language as a barrier when interacting with ESL students, d) finding material on diverse scientists to present to students, and e) students' perceptions of the teacher. Most concerns raised by the inservice teachers were centered on the well-being of the student. Finally, informal science educators held three main concerns regarding: a) the lack of diverse people in the informal science setting, b) language as a barrier when interacting with ESL audiences, and c) diverse students? home life. Most concerns were centered on the need to encourage diverse groups to participate in museum programs.