The accurate simulation of snowpack deposition and ablation beneath forested areas is confounded by the fact that the vegetation canopy strongly affects the snow surface energy balance. The canopy alters the radiation balance of the snowcover, and reduces the wind speed at the snow surface. Data collected as part of the BOREAS experiment are used to analyze the effects of a variety of forest canopies on the climate at the snow surface. Simple algorithms are developed and used to adjust climate data collected above forest canopies to the snow surface. A 2-layer coupled energy- and mass-balance snowmelt model is used to simulate the deposition and ablation of the snowpack at five forested sites within the Canadian boreal forest for the 1994-1995 snow season. Results of the snowcover simulations indicate that the net snowcover energy balance remains close to zero for the winter months, but exhibits a sharp increase in the spring months. The rapid energy gain in the spring is strongly controlled by canopy cover, and is dominated by net radiation fluxes, with minor contributions from sensible, latent, soil, and advected energy fluxes. Net snowcover irradiance dominates during the spring months due to increased solar intensity and longer day lengths, coupled with increased radiation transmission through canopies at high sun angles, and reduced snowcover albedo resulting from the deposition of fine organic debris. Turbulent (sensible and latent) energy fluxes comprise a relatively minor portion of the net snowcover energy exchange, indicating that the sub-canopy snowcover is relatively insensitive to the meteorological parameters controlling these fluxes. The low thermal conductivity of organic-rich boreal soils must be considered for studies focusing on snowcover development when soil heat flux comprises a large portion of the snowcover energy balance. Model outputs at all sites generally show good agreement with measured snow depths, indicating that the techniques used in these investigations accurately simulate both the deposition and ablation of seasonal snowcovers. Results indicate that snowcovers in the boreal environment may be more sensitive to land-use transitions, rather than climate shifts, due to the strong control exerted by vegetation canopies on radiation transfer processes. The results also suggest that simple canopy adjustment algorithms may be effectively applied to spatially distributed snowcover simulations. More data is required to evaluate the accuracy of these methods for computing energy transfer within canopies having significantly different structures than the sites used in this study. / Graduation date: 1999

Graduation date: 1992

Humans are tightly linked to their thermal microclimatic environments, yet few studies have evaluated the outdoor thermal comfort of users performing physical activity. The purpose of this research was to critically review, assess, and apply findings using the COMFA ('COMfort FormulA') human energy budget for users performing physical activity outdoors. Research objectives were: to apply an improved multi-segmented skin temperature approach to the COMFA model; to evaluate its accuracy in predicting actual thermal sensation (ATS); to implement techniques to account for human behaviours associated with clothing and metabolic variations; to spatially assess human energy budget moderating effects of urban parks; and to investigate extreme heat stress situations. To evaluate modelled mean skin temperature (T_sk), field tests were conducted on subjects performing 30 minute outdoor sessions of steady-state moderately intense activity (cycling and running). The model accurately predicted T_sk, showing significantly strong agreement (r = 0.859, p<0.01). ATS votes displayed significantly strong rank correlation with budget scores calculated using both measured and predicted T_sk (r_s = 0.507 and 0.517, respectively, p<0.01). A further improvement of Incorporating conditioning level of an individual gave more realistic estimations of metabolism for budget estimation. Adopting a new relative wind velocity (v_r) equation, which incorporates wind to body angle, revealed errors of the original v_r equation in the modelling of convective heat loss and T_sk. Application of the COMFA model in urban spaces showed that energy budgets were more closely correlated to incoming solar radiation (r = 0.941) than air temperature (r = 0.490), with a significantly strong linear regression found with radiation absorbed by a human (R^2=0.858). Treed greenspace was shown to strongly enhance thermal comfort the greatest, decreasing budgets on average by 25.5 Wm^2. Budget values were found to be a strong predictor of emergency dispatch calls received in Toronto during the July 2010 heat wave (R^2 = 0.86). This study has displayed the potential of the COMFA outdoor model as a new tool to make heat forecasting more meaningful to the public, emergency responders, and urban planners. / OGS; NSERC

The goal of this creative project was to develop a unit to be incorporated into an environmental education general studies course at Ball State University. The unit was developed as a hands-on experience activity manual.The goals of the unit were:1. to increase student awareness of the effect vegetation and water have on human comfort in the urban environment.2. to engage students in hands-on activities that relate methods for manipulating the microclimate of a space.3. to develop a pre-test/post-test containing questions which relate to the activity topics and which determine the topic knowledge of students.The manual contains an introduction, four section activities and activity subsectionexercises to combine all techniques learned in the four activity sections. Each of the four sections contain a list of objectives for the activity, explanatory text, an activity procedure, and discussion questions. Illustrations accompany the manual in order to augment the learning process for each activity. / Department of Landscape Architecture

Tree-rings were analyzed to assess the relative importance of slope position and aspect as determinants of the climate-sensitivity of sugar maple and white oak radial growth. Tree size, crown condition, forest and soil composition, and site indices were assessed to document environmental differences between site-types and to verify similarity of stands within the same site-type. Climate-sensitivity was assessed using mean between-tree correlation, principal components analysis, mean sensitivity, regression analysis, and analysis of radial growth decline after severe drought. Ecological differences were found between high and low sites on north and south facing aspects. Sugar maple did not exhibit greater climate-sensitivity than white oak. Both species showed greater climate-sensitivity on upper and south-facing slopes. / Department of Biology

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 116-126). Also available on the World Wide Web.

Thesis (M.S.)--Mississippi State University. Department of Geosciences. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 116-118). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes appendices with Foy Lake pollen and charcoal data and fire atlas metadata. Includes bibliographical references (leaves 233-244). Also available for download via the World Wide Web; free to University of Oregon users.

CAPES / O objetivo deste trabalho foi avaliar os diferentes níveis de sombreamento no sistema silvipastoril agroecológico e sua influência nos aspectos microclimáticos e qualitativos da pastagem polifitica. O experimento foi realizado no Centro Paranaense de Referência em Agroecologia (CPRA), no município de Pinhais/PR, no período de dezembro de 2015 a julho de 2016 e setembro de 2016, totalizando nove meses de avaliações. Foram utilizados oito piquetes com média de 898,75 m², composto por sistema silvipastoril com diferentes espécies arbóreas dispostas em linhas simples com pastagem polifitica. Os registros dos dados microclimáticos foram realizados um dia por mês em três faixas de horários diferentes, a saber: das 8h às 10h, 12h às 14h e das 16h às 18h. Em cada piquete foi estabelecido três posições de coleta denominadas faixas, dentro destas foram determinados três níveis de sombreamento visual (sob a copa das árvores, intermediário e a pleno sol), as variáveis microclimáticas analisadas foram: iluminância (lux), temperatura do ar (°C), umidade relativa (%), velocidade do vento (m s-1), medidos a 20 cm do solo, e temperatura superficial do solo (°C), mensurada com mira a laser direcionado para a camada superficial. As coletas referentes à forragem foram realizadas nos meses de dezembro de 2015 a abril de 2016 e junho, julho e setembro de 2016. Dentro de cada piquete foram coletadas nove amostras de forragem, referentes às faixas e níveis de sombreamento, descritas anteriormente, e cortadas rente ao solo. As amostras foram pesadas e separadas em gramíneas, leguminosas e espontâneas, em seguida foram fracionadas em folhas, colmos (pseudocolmos) e material morto para a determinação dos componentes botânicos. Para as avaliações bromatológicas os componentes folhas e colmo (pseudocolmos) foram unidos em uma mesma amostra, a fim de determinar a matéria seca, proteína bruta, fibra em detergente neutro e fibra em detergente ácido. Os resultados microclimáticos mostraram interação entre horas e pontos para iluminância e temperatura superficial do solo, de modo geral para as duas variáveis obtiveram menores valores sob a copa das árvores; as maiores diferenças foram encontradas na faixa de horário das 12h às 14h, entre o ponto de coleta sob a copa das árvores e a pleno sol. A temperatura do ar e a umidade relativa do ar obtiveram diferenças entre as horas com valores de temperatura do ar menores e umidade do ar maior, ambas na faixa das 8h às 10h. A velocidade do vento foi maior na faixa de horário das 12h às 14h. Os resultados obtidos para pastagem mostram, de modo geral, que as gramíneas apresentaram modificações em respostas ao sombreamento, com proporções de folha, relação folha/colmo, proteína bruta e matéria seca maiores no ponto de coleta sob a copa das árvores. / The objective of this work was to evaluate the different levels of shading in the agroecological silvopastoral system and its influence on the microclimatic and qualitative aspects of the pasture. The experiment was carried out at the Paranaense Reference Center in Agroecology (CPRA), in the city of Pinhais/PR, from December 2015 to July 2016 and were used, composed by silvopastoral system with different tree species arranged in simple lines with pasture. The microclimatic data records were performed one day per month in three different time bands: from 8 am to 10 am, from 12 am to 2 pm and from 4 pm to 6 pm. In each picket, three collecting positions were defined as bands, within which three levels of visual shading were determined (under the tree canopy, intermediate and full sun), the microclimatic variables analyzed were: illuminance (lux), air temperature (°C), relative humidity (%), wind speed (m s- 1), measured at 20 cm from the soil and soil surface temperature (°C), measured with a laser sight directed to the surface layer. The fodder collections were carried out in the months of December 2015 to April 2016 and June, July and September of 2016. Within each picket, nine forage samples were collected, referring to the bands and levels of shading, previously described, and cut close to the soil. The samples were weighed and separated into grasses, legumes and spontaneous, then fractionated in leaves, stems and senescent material for the determination of the botanical components. For the bromatological evaluations the leaf and stem components were united in the same sample in order to determine the dry matter, crude protein, neutral detergent fiber and acid detergent fiber. The microclimate results showed interaction between hours and points for illuminance and soil surface temperature, generally for the two variables obtained lower values under the canopy of the trees; The greatest differences were found in the time zone from 12 am to 2 pm, between the collection point under the treetops and in full sun. The air temperature and the relative humidity of the air obtained differences between the hours with lower values of air temperature and humidity of the greater air, both in the range of 8am to 10am. Wind speed was highest in the 12 am range at 2 pm. The results obtained for grazing show, in general, that the grasses showed changes in responses to the shade, with leaf proportions, leaf/stem ratio, crude protein and dry matter higher at the collection point under the tree canopy.