Quantifying microclimate heterogeneity within a contemporary plant growth facility

"December 2013.""A Thesis presented to the Faculty of the Graduate School at the University of Missouri--Columbia In Partial Fulfillment of the Requirements for the Degree M.S. Natural Resources Emphasis: Water Resources."Thesis advisor: Jason A. Hubbart, Ph.D.Three separate contemporary climate controlled greenhouse rooms in the Sears Plant Growth Facility located at the University of Missouri, Columbia, MO, USA were selected for microclimate analysis. Temperature, relative humidity, and incoming solar radiation data were logged hourly between 5/9/12 and 9/5/12 to test the efficacy of current management practices and to improve understanding of the spatial and temporal climate variability inside the greenhouse rooms. The average horizontal temperature gradient was 0.08 °C₉m⁻¹ and the maximum horizontal temperature gradient was 0.83 ðC₉m⁻¹. The average vertical temperature gradient was 2.27 °C₉m⁻¹ and the maximum lapse rate was 11.65 °C₉m⁻¹. Vapor pressure deficit (VPD) calculations were made using data as a proxy to assess plant physiological response to internal conditions. The average horizontal VPD gradient was 0.025 kPam⁻¹ and the maximum VPD gradient was 0.350 kPa₉m⁻¹ . Collectively, results indicate a heterogenous distribution of temperature and vapor pressure deficit created primarily by the active cooling system. Several recommendations are supplied to improve the homogeneity of the internal greenhouse climate, which will lead to increased productivity and profits for greenhouse managers.Includes bibliographical references (pages 115-121)

Validating Approximate Slope Homogeneity in Large Panels

Statistical inference for large data panels is omnipresent in modern economic applications. An important benefit of panel analysis is the possibility to reduce noise and thus to guarantee stable inference by intersectional pooling. However, it is wellknown that pooling can lead to a biased analysis if individual heterogeneity is too strong. In classical linear panel models, this trade-off concerns the homogeneity of slope parameters, and a large body of tests has been developed to validate this assumption. Yet, such tests can detect inconsiderable deviations from slope homogeneity, discouraging pooling, even when practically beneficial. In order to permit a more pragmatic analysis, which allows pooling when individual heterogeneity is sufficiently small, we present in this paper the concept of approximate slope homogeneity. We develop an asymptotic level $\alpha$ test for this hypothesis, that is uniformly consistent against classes of local alternatives. In contrast to existing methods, which focus on exact slope homogeneity and are usually sensitive to dependence in the data, the proposed test statistic is (asymptotically) pivotal and applicable under simultaneous intersectional and temporal dependence. Moreover, it can accommodate the realistic case of panels with large intersections. A simulation study and a data example underline the usefulness of our approach

The horizontal redistribution of anomalous vertical heat fluxes at tropical latitudes /

A study was conducted to improve quantitative understanding of how anomalous vertical heat fluxes associated with the El Nio-Southern Oscillation (ENSO) are transported poleward to maintain climate equilibrium. State-of-the-art atmospheric reanalysis output was used to quantify anomalous horizontal, tropospheric mean fluxes of sensible and latent heat monthly over a global domain during all ENSO events that occurred between January 1979 and June 2016. Results showed coherent spatial patterns (p less than 0.05) of horizontal fluxes of latent heat connecting ENSO and Pacific North American (PNA) pattern regions implying potential to quantify the interrelationship between ENSO and PNA patterns. Spatial patterns of anomalous sensible heat fluxes showed anomalous circulation dipoles consistent with PNA and North Atlantic Oscillation (NAO) patterns. Results indicated a linear relationship between ENSO, PNA, and NAO patterns that was most apparent for the PNA (NAO) pattern during January (November). Strong ENSO forcing produced a more temporally consistent linear relationship between ENSO, PNA, and NAO patterns, but was shown to transition to a non-linear relationship during January of weak ENSO forcing. Results suggested the most substantial climate impacts occurred across North America during strong El Nio and weak La Nia events when the anomalous circulations were closest to the west coast of North America. Finally, the methods presented in this work provide a mechanism for monitoring ENSO related climate impacts for North America and Western Europe in near real-time.Dissertation Co-advisors: Jason A. Hubbart, Ph.D. and Anthony Lupo, Ph.D.|Includes vita.Includes bibliographical references

Observed Mesoscale Hydroclimate Variability of North America’s Allegheny Mountains at 40.2° N

Spatial hydroclimatic variability of Eastern North America’s Allegheny Mountain System (AMS) is commonly oversimplified to elevation differences and the rain-shadow effect. Descriptive and higher order statistical properties of hourly meteorological observations (1948–2017) from seven airports were analyzed to better understand AMS climatic complexity. Airports were located along a longitudinal transect (40.2 °N) and observation infrastructure was positioned to minimize climatic gradients associated with insolation, slope, and aspect. Results indicated average ambient temperature was well correlated with airport elevation (R2 = 0.97). However, elevation was relatively poorly correlated to dew point temperature (R2 = 0.80) and vapor pressure deficit (R2 = 0.61) heterogeneity. Skewness and kurtosis of ambient and dew point temperatures were negative at all airports indicating hourly values below the median were more common and extreme values were less common than a normal distribution implies. Westerly winds accounted for 54.5% of observations indicating prevailing winds misrepresented nearly half of AMS weather phenomena. The sum of maximum hourly precipitation rates was maximized in Philadelphia, PA implying a convective precipitation maximum near the border of Piedmont and Coastal Plain provinces. Results further indicate the AMS represents a barrier to omnidirectional moisture advection suggesting physiographic provinces are characterized by distinct evapotranspiration and precipitation regimes. The current work draws attention to observed mesoscale hydroclimatic heterogeneity of the AMS region and identifies mechanisms influencing local to regional water quantity and quality issues that are relevant to many locations globally

Climatic Trends of West Virginia: A Representative Appalachian Microcosm

During the late 19th and very early 20th centuries widespread deforestation occurred across the Appalachian region, USA. However, since the early 20th century, land cover rapidly changed from predominantly agricultural land use (72%; 1909) to forest. West Virginia (WV) is now the USA’s third most forested state by area (79%; 1989–present). It is well understood that land cover alterations feedback on climate with important implications for ecology, water resources, and watershed management. However, the spatiotemporal distribution of climatic changes during reforestation in WV remains unclear. To fill this knowledge gap, daily maximum temperature, minimum temperature, and precipitation data were acquired for eighteen observation sites with long periods of record (POR; ≥77 years). Results indicate an increasingly wet and temperate WV climate characterized by warming summertime minimum temperatures, cooling maximum temperatures year-round, and increased annual precipitation that accelerated during the second half (1959–2016) of the POR. Trends are elevation dependent and may be accelerating due to local to regional ecohydrological feedbacks including increasing forest age and density, changing forest species composition, and increasing globally averaged atmospheric moisture. Furthermore, results imply that excessive wetness may become the primary ecosystem stressor associated with climate change in the USA’s rugged and flood prone Appalachian region. The Appalachian region’s physiographic complexity and history of widespread land use changes makes climatic changes particularly dynamic. Therefore, mechanistic understanding of micro- to mesoscale climate changes is imperative to better inform decision makers and ensure preservation of the region’s rich natural resources

Changing Climatic Averages and Variance: Implications for Mesophication at the Eastern Edge of North America’s Eastern Deciduous Forest

Observed conversion of xerophytic warm genera species to mesophytic cool genera species in North America’s Eastern Deciduous Forest (EDF) suggests species composition is in disequilibrium with recent climatic warming. However, increasing annual average temperatures is an oversimplification of long-term climatic change and the importance of climate variance is often neglected. Seven-year moving averages and standard deviations of annually averaged maximum temperatures, minimum temperatures, daily precipitation, and vapor pressure deficits (VPD) in West Virginia, USA were quantified over a 111-year period of record (1906–2016). Maximum temperatures decreased significantly (−5.3%; p \u3c 0.001), minimum temperatures increased significantly (7.7%; p \u3c 0.001), and precipitation increased (2.2%; p = 0.107). Additionally, maximum temperature variance decreased (−17.4%; p = 0.109), minimum temperature variance decreased significantly (−22.6%; p = 0.042), and precipitation variance increased significantly (26.6%; p = 0.004). Results indicate a reduced diurnal temperature range and significant reductions in estimated VPD (10.3%; p \u3c 0.001) that imply increased relative humidity, cloud cover, and soil moisture that may support increasingly abundant mesophytic cool genera species. Feedback mechanisms associated with extensive changes in land use, fire suppression, and browser population may have exacerbated climatic changes. Long-term assessments of changing climatic averages and variance are needed to ensure sustainability of forest ecosystem services, health, and productivity in a swiftly changing climate across the broader EDF region and similar temperate forest ecosystems globally

Lower Bounds for R\'enyi Differential Privacy in a Black-Box Setting

We present new methods for assessing the privacy guarantees of an algorithm with regard to R\'enyi Differential Privacy. To the best of our knowledge, this work is the first to address this problem in a black-box scenario, where only algorithmic outputs are available. To quantify privacy leakage, we devise a new estimator for the R\'enyi divergence of a pair of output distributions. This estimator is transformed into a statistical lower bound that is proven to hold for large samples with high probability. Our method is applicable for a broad class of algorithms, including many well-known examples from the privacy literature. We demonstrate the effectiveness of our approach by experiments encompassing algorithms and privacy enhancing methods that have not been considered in related works