A Method for Hemispherical Ground Based Remote Sensing of Urban Surface Temperatures

This thesis presents a method for deriving time-continuous urban surface temperature and heat island assessments from hemispherical ground-based measurements of upwelling thermal radiation. The method, developed to overcome geometric and temporal biases inherent in traditional thermal remote sensing of urban surface climates, uses a sensor view model in conjunction with a radiative transfer code to derive atmospherically corrected, hemispherical radiometric urban surface temperatures. These are used to derive two long-term climatologies of surface urban heat island (sUHI) magnitudes for Basel, Switzerland and Vancouver, Canada. sUHI development shows significant variation based on time-of-day, season, and ambient and synoptic conditions. Results also show large differences in remote sensed sUHI from hemispherical, nadir and complete representations of the urban surface, with a nadir view overestimating seasonal sUHImax from a complete view by nearly a factor of two. In contrast, a hemispherical view provides significantly more representative, time-continuous urban surface temperature and sUHI analysis

Feasibility of Thermosyphons to Impede the Progress of Coastal Permafrost Erosion Along the Norther Coastline of Alaska

Presented to the Faculty of the University of Alaska Anchorage in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCEThis study seeks to investigate the feasibility of installing thermosyphons at Drew Point, Alaska to mitigate thermally-induced coastline erosion. Portions of the northern Alaska coastline have been receding at increasing rates and putting in peril infrastructure, environmental habitats, and small villages. Slowing or eliminating the erosion would prevent emotional village relocations and costly infrastructure maintenance and relocations. Climate and soil data from Drew Point and Barrow, Alaska are used as input variables in a numerical modeling software program to determine accurate soil thermal properties to be used in a thermosyphon design. Generalized cost considerations are presented and it is determined that thermosyphons may be an effective mitigation strategy to combat coastal erosion, however, future additional modeling could optimize a design and provide for refinements in the cost analysis.Abstract / Table of Contents / List of Figures / List of Tables / Acknowledgements / Introduction and Background / Objective and Methodology / Data Collection and Climate Analysis / Modeling / Heat Transfer Analysis / Thermosyphon Design / Discussion / Conclusion / Reference

Measuring and modeling near-surface reflected and emitted radiation fluxes at the FIFE site

Information is presented pertaining to the measurement and estimation of reflected and emitted components of the radiation balance. Information is included about reflectance and transmittance of solar radiation from and through the leaves of some grass and forb prairie species, bidirectional reflectance from a prairie canopy is discussed and measured and estimated fluxes are described of incoming and outgoing longwave and shortwave radiation. Results of the study showed only very small differences in reflectances and transmittances for the adaxial and abaxial surfaces of grass species in the visible and infrared wavebands, but some differences in the infrared wavebands were noted for the forbs. Reflectance from the prairie canopy changed as a function of solar and view zenith angles in the solar principal plane with definite asymmetry about nadir. The surface temperature of prairie canopies was found to vary by as much as 5 C depending on view zenith and azimuth position and on the solar azimuth. Aerodynamic temperature calculated from measured sensible heat fluxes ranged from 0 to 3 C higher than nadir-viewed temperatures. Models were developed to estimate incoming and reflected shortwave radiation from data collected with a Barnes Modular Multiband Radiometer. Several algorithms for estimating incoming longwave radiation were evaluated and compared to actual measures of that parameter. Net radiation was calculated using the estimated components of the shortwave radiation streams, determined from the algorithms developed, and from the longwave radiation streams provided by the Brunt, modified Deacon, and the Stefan-Boltzmann models. Estimates of net radiation were compared to measured values and found to be within the measurement error of the net radiometers used in the study

Influence of temperature difference (water-cover surface) on the performance of a compact hemispherical solar still

The study investigated the influence of temperature difference (ΔT) between evaporative and condensing surface temperature on water productivity of hemispherical solar still. The still was developed, tested and evaluated under the climatic conditions of Ile-Ife, Nigeria, to obtain an average distillate yield per hour per day for different combination of basin temperature, water temperature, transparent cover temperature, ambient temperature and solar intensity. Results indicated a decrease in the hourly water yield as (ΔT) increases. Regression analysis revealed that ΔT has no significant influence on the hourly water yield (P > 0.05). Maximum water productivity was obtained for a low condensing surface temperature and a high evaporative surface temperature. The study concluded that the improvement on water productivity of solar still can be achieved by enhancing the evaporative and condensing surface temperature. Methods for obtaining higher evaporating temperature should be sought in order to boost water productivity of solar stills. Keywords: Temperature difference, Evaporative surface, Condensing surface, Hourly water yield, Heat losses

Assessing the cooling impact of tree canopies in an intensively modified tropical landscape

Ilmastonmuutoksella on ennustettu olevan kohtalokkaita seurauksia trooppisten alueiden hauraille ekosysteemeille, ja se uhkaa sekä maailmanlaajuista biodiversiteettiä että miljoonien ihmisten ruokaturvaa. Metsien on havaittu puskuroivan ilmaston lämpenemistä, ja mikroilmastolliset olosuhteet puiden latvustojen alla eroavat merkittävästi ympäröivästä makroilmastosta. Puut viilentävät lähiympäristöään monien biofysikaalisten mekanismien avulla, ja viilentävä vaikutus on havaittavissa myös metsän ulkopuolella kasvavilla puilla. Kaukokartoitus tarjoaa uusia mahdollisuuksia tutkia, kuinka topografia ja latvuspeite vaikuttavat lämpötiloihin sekä paikallisesti että alueellisesti. Tämän tutkimuksen tarkoituksena oli tutkia latvuspeitteen vaikutusta mikroilmastoon ja maan pinnan lämpötilaan Kenian Taitavuorilla. Eri latvuspeiton omaaville paikoille asennettiin 19 mikroilmaston mittaamiseen tarkoitettua sensoria, jotka tallensivat lämpötilaa. Lisäksi käytettiin Landsat 8 lämpöinfrapunasensorin (TIRS) tallentamaa dataa maan pinnan lämpötilasta (LST). Tutkimuksessa keskityttiin erityisesti päiväsajan keski- ja maksimilämpötiloihin, jotka mitattiin lämpötilasensoreilla kesä-heinäkuussa 2019. LST oli tallennettu 4. heinäkuuta 2019 ja laskettiin käyttämällä single-channel -metodia (SC). Lämpötiloja verrattiin korkean resoluution laserkeilausaineistoon (ALS) vuosilta 2014 ja 2015, jotta topografian ja latvuspeitteen vaikutuksia alueen lämpötiloihin voitaisiin tarkastella. Monimuuttujaregressiomallilla tutkittiin topografian ja latvuspeitteen yhteisvaikutuksia. Tulokset osoittavat negatiivisen lineaarisen suhteen päiväsaikaisten keski- ja maksimilämpötilojen ja latvuspeitteen välillä (R2 = 0.6–0.74). Kaikki lisäys latvuspeitteen määrään vaikutti negatiivisesti lämpötiloihin jokaisella mittauskorkeudella, vaikutuksen ollessa suurin pintalämpötiloihin. Ero 0 % ja 100 %:n latvuspeitteen alueilla oli keskilämpötiloissa 4.6–5.9 ˚C ja maksimilämpötiloissa 8.9–12.1 ˚C. Latvuspeite vaikutti negatiivisesti myös LST:en kulmakertoimella 5.0 ˚C. Latvuspeitteen vaikutus LST:en oli riippuvainen korkeudesta, ja merkittävä jakolinja löydettiin 1000 metrin korkeudelta, jossa latvuspeitteen vaikutus vuorilla laski puoleen verrattuna alankoihin. Tulosten perusteella voitiin päätellä, että puilla on merkittävä vaikutus sekä mikroilmastoon että maan pinnan lämpötilaan, mutta on riippuvainen korkeudesta. Tämä osoittaa, että puiden merkitys kasvaa mitä kuumemmasta ympäristöstä on kyse, ja että puuston säilyttäminen olisi erityisen tärkeää alankoalueilla. Metsän ulkopuolella kasvavat puut voivat lisätä kestävyyttä ilmastonmuutoksen edessä tutkimusalueella, ja jäljellä olevat metsäsirpaleet on syytä säilyttää alueellisen lämpötilan hallitsemiseksi.Global warming is expected to have detrimental consequences on fragile ecosystems in the tropics and to threaten both the global biodiversity as well as food security of millions of people. Forests have the potential to buffer the temperature changes, and the microclimatic conditions below tree canopies usually differ substantially from the ambient macroclimate. Trees cool down their surroundings through several biophysical mechanisms, and the cooling benefits occur also with trees outside forest. Remote sensing technologies offer new possibilities to study how tree cover affects temperatures both in local and regional scales. The aim of this study was to examine canopy cover’s effect on microclimate and land surface temperature (LST) in Taita Hills, Kenya. Temperatures recorded by 19 microclimate sensors under different canopy covers in the study area and LST estimated by Landsat 8 thermal infrared sensor (TIRS) were studied. The main interest was in daytime mean and maximum temperatures measured with the microclimate sensors in June-July 2019. The Landsat 8 imagery was obtained in July 4, 2019 and LST was retrieved using the single-channel method. The temperature records were combined with high-resolution airborne laser scanning (ALS) data of the area from years 2014 and 2015 to address how topographical factors and canopy cover affect temperatures in the area. Four multiple regression models were developed to study the joint impacts of topography and canopy cover on LST. The results showed a negative linear relationship between daytime mean and maximum temperatures and canopy cover percentage (R2 = 0.6–0.74). Any increase in canopy cover contributed to reducing temperatures at all microclimate measuring heights, the magnitude being the highest at soil surface level. The difference in mean temperatures between 0% and 100% canopy cover sites was 4.6–5.9 ˚C and in maximum temperatures 8.9–12.1 ˚C. LST was also affected negatively by canopy cover with a slope of 5.0 ˚C. It was found that canopy cover’s impact on LST depends on altitude and that a considerable dividing line existed at 1000 m a.s.l. as canopy cover’s effect in the highlands decreased to half compared to the lowlands. Based on the results it was concluded that trees have substantial effect on both microclimate and LST, but the effect is highly dependent on altitude. This indicates trees’ increasing significance in hot environments and highlights the importance of maintaining tree cover particularly in the lowland areas. Trees outside forests can increase climate change resilience in the area and the remaining forest fragments should be conserved to control the regional temperatures

Towards improved bioaerosol model validation and verification

Bioaerosols, comprised of bacteria, fungi and viruses are ubiquitous in ambient air. Known to adversely affect human health, the impact of bioaerosols on a population often manifests as outbreaks of illnesses such as Legionnaires Disease and Q fever, although the concentrations and environmental conditions in which these impacts occur are not well understood. Bioaerosol concentrations vary from source to source, but specific industrialised human activities such as water treatment, intensive agriculture and open windrow composting facilitate the generation of bioaerosol concentrations many times higher than natural background levels. Bioaerosol sampling is currently undertaken according to the requirements of the Environment Agency’s regulatory framework, in which the collection of bioaerosols and not its long-term measurement is of most importance. As a consequence, sampling devices are often moved around site according to changing wind direction and sampling intervals are invariably short-term. The dispersion modelling of bioaerosols from composting facilities typically relies on proxy pollutant parameters. In addition, the use of short term emission data gathering strategies in which monitors are moved frequently with wind direction, do not provide a robust reliable and repeatable dataset by which to validate any modelling or to verify its performance. New sampling methods such as the Spectral Intensity Bioaerosol Sensor (SIBS) provide an opportunity to address several gaps in bioaerosol model validation and verification. In the context of model validation, this paper sets out the current weaknesses in bioaerosol monitoring from the perspective of robust modelling requirements

Evolutionary Dynamics of Rapid, Microgeographic Adaptation in an Amphibian Metapopulation

Wild organisms can rapidly adapt to changing environments, even at fine spatial scales. This fact prompts hope that contemporary local adaptation may buffer some of the negative anthropogenic impacts to ecosystems. However, there are limits to the pace of adaptation. Understanding the adaptive potential—and limitations—of individual species at fine-resolution is an important task if we hope to accurately predict the repercussions of future climate and landscape change on biodiversity. My dissertation takes advantage of an uncommonly long-observed and closely-studied system to paint a comprehensive picture of evolution over time in association with shifts in ecological contexts. In this dissertation, I show evidence of rapid, microgeographic evolution in response to climate within a metapopulation of wood frogs (Rana sylvatica). Critically, I show that populations separated by tens to hundreds of meters—well within the dispersal ability of the species—exhibited considerable shifts in development rates over a period of two decades, or roughly 6-9 generations. Using historical climate data and new methods of assessing landscape change, I show that these changes were mainly a response to warming climates. The ecological contexts experienced by the metapopulation are associated with the evolution of physiological rates. Specifically, I show that climate change seems to have caused a counter-intuitive delay in spring breeding phenology while drought and warming later in the larval development period correspond with a shift toward earlier metamorphosis. The picture that emerges is of a contracting developmental window, which is expected to select for faster intrinsic development rates. Superimposed on the metapopulation-wide shift to faster development was a pattern of counter-gradient variation reflecting a similar pattern seen two decades prior. Furthermore, I empirically demonstrate a trade-off between faster development and a swimming performance trait that strongly contributes to fitness. This trade-off helps to explain why intrinsic development rates vary spatially with pond temperatures, but in the opposite direction of the relationship with temperature over time. Though the evidence for rapid adaptation to climate change presented in this dissertation reveals that evolution can buffer populations from extinction, it also entreats caution. There is a clear trend of demographic decline among wood frog populations that experienced greater magnitudes of environmental change. In fact, the three populations that suffered local extinctions over the 20-year course of observations inhabited ponds characterized by the greatest change in temperature or canopy

Cool roof technology in London: An experimental and modelling study

This is the post-print version of the final paper published in Journal of Energy and Buildings. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.One of the primary reasons for the application of cool materials is their energy and associated environmental impact on the built environment. Cool materials are usually applied on the roof of buildings to reduce cooling energy demand. The relative benefits of this reduction depend on the construction of the building, external weather conditions and use of the building. This paper examines the impact from the application of a reflective paint on a flat roof in a naturally ventilated office building in the area of London, UK where the climate is moderate with high heating demand by buildings. The environmental conditions (internal/external air and surface temperatures) of the building were monitored before and after the application of the cool roof during the summer. It was found that internal temperatures were reduced after the application of the cool roof. The building was modelled using TRNSYS and the model was calibrated successfully using the measurements. A parametric analysis was carried out by varying the reflectivity and insulation of the roof and ventilation rate; the heating and cooling demand for a year was calculated using the Summer Design Year for London as the weather file. It was found that cooling demand is significantly reduced, heating demand is increased and the total energy savings vary between 1 and 8.5% relative to an albedo of 0.1 for the same conditions. In free floating (naturally ventilated) buildings summer comfort is improved but there is a penalty of increased heating energy during the winter. Thermal comfort can be improved by an average of 2.5 °C (operative temperature difference for a change of 0.5 in albedo) but heating demand could be increased by 10% for a ventilation rate of 2 air changes per hour. The results indicate that in the case of temperate climates the type, operation and thermal characteristics of the building should be considered carefully to determine potential benefits of the application of cool roof technology. For the examined case-study, it was found that a roof reflectivity of 0.6–0.7 is the optimum value to achieve energy savings in a cooled office, improve summer internal thermal conditions in a non-cooled office (albeit with some heating energy penalty). It indicates that it is a suitable strategy for refurbishment of existing offices to improve energy efficiency or internal environmental conditions in the summer and should be considered in the design of new offices together with other passive energy efficient strategies.Intelligent Energy Europe (IEE

Carrion-associated arthropods in rural and urban environments

Preferences of arthropods are important in forensic entomology, as the species collected can help determine the postmortem interval or if remains have been moved. This study looked at arthropods that are attracted to pig carcasses in rural and urban habitats in Northwest Indiana. The species and number of carrion-associated arthropods that are found at a carcass vary with habitat type, month, and stage of decomposition. Lucilia sericata (Diptera: Calliphoridae) is a synanthropic species that was found in higher numbers in urban locations for both adults and larvae. Though L. sericata had higher numbers in urban habitats, caution must be exercised when using the information in a criminal case, as adults and larvae were still collected in rural habitats, and thus presence of L. sericata does not conclusively show that remains were previously located in an urban habitat. No other Diptera or Coleoptera species showed a preference for habitat type. Isopoda were found in higher numbers in urban habitats. Calliphoridae species, except for L. sericata, had differences in numbers between the months studied (June-October). Most adult taxa and all larval taxa showed differences in numbers between decomposition stages. Succession tables for all arthropods and non-arthropods collected were created to show when taxa that were found at the carcasses. Crickets (Orthoptera: Gryllidae) were observed feeding on the carcass, and feeding holes left in the carcasses by dipteran larvae. The cricket feeding modified the appearance of the holes, which could be confused for antemortem or perimortem wounds in a criminal investigation