Downscaling GLDAS Soil Moisture Data in East Asia through Fusion of Multi-Sensors by Optimizing Modified Regression Trees

Soilmoisture is a key part of Earth's climate systems, including agricultural and hydrological cycles. Soil moisture data from satellite and numerical models is typically provided at a global scale with coarse spatial resolution, which is not enough for local and regional applications. In this study, a soil moisture downscaling model was developed using satellite-derived variables targeting Global Land Data Assimilation System (GLDAS) soil moisture as a reference dataset in East Asia based on the optimization of a modified regression tree. A total of six variables, Advanced Microwave Scanning Radiometer 2 (AMSR2) and Advanced SCATterometer (ASCAT) soil moisture products, Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM), and MODerate resolution Imaging Spectroradiometer (MODIS) products, including Land Surface Temperature, Normalized Difference Vegetation Index, and land cover, were used as input variables. The optimization was conducted through a pruning approach for operational use, and finally 59 rules were extracted based on root mean square errors (RMSEs) and correlation coefficients (r). The developed downscaling model showed a good modeling performance (r = 0.79, RMSE = 0.056 m(3)center dot m(3), and slope = 0.74). The 1 km downscaled soil moisture showed similar time series patterns with both GLDAS and ground soil moisture and good correlation with ground soil moisture (average r = 0.47, average RMSD = 0.038 m(3)center dot m(3)) at 14 ground stations. The spatial distribution of 1 km downscaled soil moisture reflected seasonal and regional characteristics well, although the model did not result in good performance over a few areas such as Southern China due to very high cloud cover rates. The results of this study are expected to be helpful in operational use to monitor soil moisture throughout East Asia since the downscaling model produces daily high resolution (1 km) real time soil moisture with a low computational demand. This study yielded a promising result to operationally produce daily high resolution soil moisture data from multiple satellite sources, although there are yet several limitations. In future research, more variables including Global Precipitation Measurement (GPM) precipitation, Soil Moisture Active Passive (SMAP) soil moisture, and other vegetation indices will be integrated to improve the performance of the proposed soil moisture downscaling model.ope

Sources of Atmospheric Fine Particles and Adsorbed Polycyclic Aromatic Hydrocarbons in Syracuse, New York

Land surface temperature (LST) images from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor have been widely utilized across scientific disciplines for a variety of purposes. The goal of this dissertation was to utilize MODIS LST for three spatial modeling applications within the conterminous United States (CONUS). These topics broadly encompassed agriculture and human health. The first manuscript compared the performance of all methods previously used to interpolate missing values in 8-day MODIS LST images. At low cloud cover (\u3c30%), the Spline spatial method outperformed all of the temporal and spatiotemporal methods by a wide margin, with median absolute errors (MAEs) ranging from 0.2°C-0.6°C. However, the Weiss spatiotemporal method generally performed best at greater cloud cover, with MAEs ranging from 0.3°C-1.2°C. Considering the distribution of cloud contamination and difficulty of implementing Weiss, using Spline under all conditions for simplicity would be sufficient. The second manuscript compared the corn yield predictive capability across the US Corn Belt of a novel killing degree day metric (LST KDD), computed with daily MODIS LST, and a traditional air temperature-based metric (Tair KDD). LST KDD was capable of predicting annual corn yield with considerably less error than Tair KDD (R2 /RMSE of 0.65/15.3 Bu/Acre vs. 0.56/17.2 Bu/Acre). The superior performance can be attributed to LST’s ability to better reflect evaporative cooling and water stress. Moreover, these findings suggest that long-term yield projections based on Tair and precipitation alone will contain error, especially for years of extreme drought. Finally, the third manuscript assessed the extent to which daily maximum heat index (HI) across the CONUS can be estimated by MODIS multispectral imagery in conjunction with land cover, topographic, and locational factors. The derived model was capable of estimating HI in 2012 with an acceptable level of error (R 2 = 0.83, RMSE = 4.4°F). LST and water vapor (WV) were, by far, the most important variables for estimation. Expanding this analytical framework to a more extensive study area (both temporally and spatially) would further validate these findings. Moreover, identifying an appropriate interpolation and downscaling approach for daily MODIS imagery would substantially increase the utility of the corn yield and HI models

Global downscaling of remotely sensed soil moisture using neural networks

Characterizing soil moisture at spatiotemporal scales relevant to land surface processes (i.e., of the order of 1&thinsp;km) is necessary in order to quantify its role in regional feedbacks between the land surface and the atmospheric boundary layer. Moreover, several applications such as agricultural management can benefit from soil moisture information at fine spatial scales. Soil moisture estimates from current satellite missions have a reasonably good temporal revisit over the globe (2–3-day repeat time); however, their finest spatial resolution is 9&thinsp;km. NASA's Soil Moisture Active Passive (SMAP) satellite has estimated soil moisture at two different spatial scales of 36 and 9&thinsp;km since April 2015. In this study, we develop a neural-network-based downscaling algorithm using SMAP observations and disaggregate soil moisture to 2.25&thinsp;km spatial resolution. Our approach uses the mean monthly Normalized Differenced Vegetation Index (NDVI) as ancillary data to quantify the subpixel heterogeneity of soil moisture. Evaluation of the downscaled soil moisture estimates against in situ observations shows that their accuracy is better than or equal to the SMAP 9&thinsp;km soil moisture estimates.</p

Households at Risk : Integrated Assessment of Drought Hazard and Social Vulnerability in the Cuvelai-Basin of Angola and Namibia

Droughts are phenomena that occur worldwide, in humid and arid environments as well as in the Global North and the Global South. They are considered as slow onset hazards that affect more people than any other natural process with an estimated economic damage of USD 135 Billion and 12 Million casualties globally between 1900 and 2013 (Masih et al., 2014, p. 3636). Sub-Saharan Africa (SSA) is a major drought hot-spot due to vulnerable livelihoods (e.g. dominance of rain-fed agriculture), limited capacities (e.g. financial, institutional), weak infrastructure (e.g. water, mobility) and political instability (e.g. conflicts, corruption). When droughts occur, as recently triggered by El Niño (2015/2016), vulnerability conditions of the affected societies determine, if drought risk manifests as a disaster. As a critical, recent example, the drought in Somalia resulted in a serious humanitarian disaster primarily as the precarious vulnerability situation was further deteriorated by political and violent conflicts (Maxwell et al., 2016). Overall, SSA faces severe challenges to manage drought risk, primarily due to two reasons: First, despite progress, the living conditions remain difficult with prevailing poverty, limited health services and ongoing political unrest in many regions (UNECA et al., 2015). This is alarming, especially against the projected population growth of about 1.3 Billion people in Africa until 2050 (UN-DESA, 2015, p. 3). Second, achieving good living conditions for all, as envisioned by the Sustainable Development Goals (SDG), is a challenge, as climate projections indicate a likely increase of drought frequency and severity in SSA. Higher rainfall variability paired with a strong increase in average temperatures (Niang et al., 2014) will render today's exceptional droughts as the new normal in the near future. These urgent problems require sustainable solutions to improve short- and long-term adaptation. Transdisciplinary science that conflates the strengths of academic disciplines and stakeholders from politics and society is needed to develop risk reduction strategies. Under the umbrella of the Southern African Science Service Centre for Climate Change and Adaptive Land Management (SASSCAL), this thesis makes a contribution to integrated drought risk management schemes by assessing the drought hazard conditions and the societal vulnerability settings in a case study region: the Cuvelai-Basin. This transnational region across Namibia and Angola regularly experiences droughts as recently during 2012 – 2015 with hundreds of thousands of people being water and food insecure (DDRM, 2013; UN-OCHA, 2012). Environmentally, it covers a gradient from humid in the north to semi-arid conditions in the south with associated vegetation patterns. The population practices subsistence agriculture and livestock herding with tendencies of urbanization and lifestyle changes. The societal pre-conditions in both countries are heterogeneous with Angola having experienced decades of civil war until 2002 while Namibia saw continuous institutional and infrastructural development particularly after independence in 1990. To capture the multi-layered impacts of droughts on people's livelihoods, the thesis follows an interdisciplinary approach in the sense of integrating methodologies from physical and human geography. Key questions to be answered are (i) how droughts impact on local livelihoods, (ii) how the environmental drought hazard manifests, (iii) which societal groups are most vulnerable and (iv) what are risk mitigation strategies. Based on the theory of societal relations to nature, a guideline for a social-ecological drought risk assessment is proposed and exemplarily carried out in this thesis. First, a qualitative research phase was conducted to gain system knowledge, followed by quantitative analyses of environmental parameters on the drought hazard and socio-economic variables for drought vulnerability. Finally, this data was conflated in the Household Drought Risk Index (HDRI) to gain orientation knowledge and quantify risk levels among the households in the basin. This provided transformation knowledge to develop and identify risk mitigation strategies. The initial qualitative survey (n = 26) explored the drought impact on local livelihoods. It revealed structural insights into people's utilization of water resources and the negative impacts of drought on physical and mental health, family/community life and livelihood maintenance. Coping mechanisms were identified on multiple levels from the household level (e.g. selling of agricultural products) via the community (e.g. neighbourly support) to the governmental level (e.g. drought relief). As critical entry point for droughts, the water and food consumption patterns were identified that shape a household either more or less sensitive. The internal capital endowment (human, social, financial, physical and natural) and the infrastructural and institutional endowment of an area determine a household's ability to cope with drought. These qualitative insights culminated in the construction of the HDRI indicator that was populated with data in the subsequent research phases. To capture the drought hazard, three common drought indicators were combined in the Blended Drought Index (BDI). This integrated drought indicator incorporates meteorological and agricultural drought characteristics that impair the population's ability to ensure food and water security. The BDI uses a copula function to combine common standardized drought indicators that describe precipitation, evapotranspiration, soil moisture and vegetation conditions. Remote sensing products were processed to analyse drought frequency, severity and duration. In this regard, the uncertainty among a range of rainfall products was evaluated to identify the product that corresponds best to local rain gauge measurements. The integrated drought hazard map indicates the north of the Etosha pan and the area along the Kunene River to be most threatened by droughts. Temporally, the BDI correlates well with millet/sorghum yield (r = 0.51) and local water consumption (r = -0.45) and outperforms conventional indicators. The vulnerability perspective was captured using primary socio-economic data from a household survey (n = 461). The consumption patterns reveal a statistically significant switch from critical sources (e.g. wells, subsistence products) during the rainy season to more reliable sources (e.g. tap water, markets) during the dry period. Households with a high dependence on critical sources are particularly sensitive to drought. The capital endowment of households is heterogeneous, especially on a rural-urban gradient and between Namibia and Angola. Human and financial capital turned out to be important control variables in addition to the infrastructural and institutional endowment of an area. Overall, the HDRI results show that the Angolan population shows higher levels of risk, particularly caused by less developed infrastructural systems, weaker institutional capabilities and less coping capacities. Urban inhabitants follow less drought-sensitive livelihood strategies, but are still connected to drought conditions in rural areas due to family relations with obligations and benefits. Furthermore, the spatial HDRI estimates point to areas in Angola and Namibia that are both drought-threatened and vulnerable. The thesis results indicate the following recommendations for policy and science: First, the continuous monitoring of drought patterns in the basin should consider drought indicators that go beyond precipitation metrics and incorporate people's vulnerability to develop integrated Drought Information Systems. Second, reducing the sensitivities of the population requires enhanced local water buffers via better water use efficiencies. This is true for both blue and green water flows. Water-saving irrigation schemes in combination with decentral rain- and floodwater harvesting are promising opportunities. Furthermore, centralized backup infrastructures of water supply and market systems need to be expanded. Third, local community solidarity is an important institutional backbone for the population to cope with drought and adapt to future changes. In particular rural development efforts should go beyond technological interventions and support community-building, collective-action and capacity development in water management and agricultural production to decouple livelihoods from local rainfall.Dürren sind Phänomene, die weltweit sowohl in humiden als auch ariden Räumen sowie im Globalen Norden und im Globalen Süden auftreten. Sie gelten als langsam einsetzende Gefahren, die mehr Menschen betreffen als jeder andere natürliche Prozess mit einem geschätzten wirtschaftlichen Schaden von 135 Mrd. US-Dollar und 12 Mio. Toten weltweit zwischen 1900 und 2013 (Masih et al., 2014, p. 3636). Sub-Sahara Afrika gilt als Krisenherd aufgrund vulnerabler Lebensgrundlagen (z.B. Dominanz des Regenfeldbaus), begrenzter Kapazitäten (z.B. finanzielle, institutionelle), schwacher Infrastruktur (z.B. Trinkwasser, Mobilität) und politischer Instabilität (z.B. Konflikte, Korruption). Treten Dürren auf, wie kürzlich verstärkt durch El Niño (2015/2016), bestimmt die Vulnerabilität der Gesellschaft, ob sich das Dürrerisiko als Katastrophe manifestiert. Ein kritisches Beispiel ist die Dürre in Somalia, die v.a. zu einer humanitären Katastrophe wurde, da die prekären Vulnerabilitäts-bedingungen durch gewaltsame, politische Konflikte weiter verschlechtert wurden (Maxwell et al., 2016). Insgesamt steht Afrika aus zwei Gründen vor großen Heraus-forderungen bei der Bewältigung des Dürrerisikos: Erstens, sind die Lebensbedingungen u.a. aufgrund anhaltender Armut, begrenzter Gesundheitsversorgung und politischer Unruhen weiterhin schwierig (UNECA et al., 2015). Dies ist alarmierend, v.a. vor dem Hintergrund eines prognostizierten Bevölkerungswachstums von 1,3 Mrd. bis 2050 (UN-DESA, 2015, p. 3). Zweitens, ist die Schaffung guter Lebensbedingungen nach den Zielen für nachhaltige Entwicklung (SDG) eine Herausforderung, da mit dem Klimawandel eine Zunahme von Dürrehäufigkeit und -stärke zu erwarten ist. Höhere Niederschlags-variabilität gepaart mit einem starken Anstieg der Durchschnittstemperatur (Niang et al., 2014) werden die heutigen extremen Dürren in Zukunft zur neuen Normalität machen. Diese Probleme erfordern nachhaltige Lösungen, um kurz- und langfristige Anpassungen zu ermöglichen. Transdisziplinäre Forschung ist gefordert, welche die Stärken wissenschaftlicher Disziplinen und Akteure aus Politik und Gesellschaft bündelt, um geeignete Strategien zur Risikominderung zu erarbeiten. Unter dem Dach des Southern African Science Service Centre for Climate Change and Adaptive Land Management (SASSCAL) leistet diese Dissertation einen Beitrag zu integrierten Managementansätzen von Dürrerisiken, indem sie die naturräumliche Gefährdung kombiniert mit der gesellschaftlichen Vulnerabilität anhand einer Fallstudie untersucht: dem Cuvelai-Becken. Diese transnationale Region in Namibia und Angola ist regelmäßig Dürren ausgesetzt, wie zuletzt in den Jahren 2012 – 2015 mit Wasser- und Ernährungsunsicherheit für Hunderttausende von Menschen (DDRM, 2013; UN-OCHA, 2012). Naturräumlich erstreckt sich die Region von einem humiden Norden in einen semi-ariden Süden mit entsprechenden Vegetationsverhältnissen. Die Bevölkerung betreibt Subsistenzland-wirtschaft und Viehzucht, wobei Urbanisierungstendenzen und Lebensstiländerungen an Dynamik gewinnen. Die gesellschaftlichen Voraussetzungen sind heterogen: Während Angola bis 2002 Jahrzehnte des Bürgerkriegs erlebte, erfuhr Namibia v.a. nach der Unabhängigkeit 1990 eine kontinuierliche institutionelle und infrastrukturelle Entwicklung. Um die vielschichtigen Auswirkungen von Dürren auf die Lebensgrundlagen zu erfassen, verfolgt diese Dissertation einen interdisziplinären Ansatz im Sinne der Integration von Methoden aus der Physischen- und Humangeographie. Kernfragen darin sind (i) wie sich Dürren auf die Lebensgrundlagen auswirken, (ii) wie sich die naturräumliche Dürregefährdung manifestiert, (iii) welche gesellschaftlichen Gruppen vulnerabel sind und (iv) welche Strategien zur Risikominderung geeignet sind. Dabei entwickelt die Dissertation auf Basis der Theorie gesellschaftlicher Naturverhältnisse einen Leitfaden für eine sozial-ökologische Risikoabschätzung und wendet diesen in der vorliegenden Fallstudie an. Zunächst wurde eine qualitative Forschungsphase durchgeführt, um Systemwissen zu gewinnen, gefolgt von einer quantitativen Analyse von Umweltparametern zur Abschätzung der Dürregefahr sowie sozioökonomischer Variablen für die Abschätzung der Vulnerabilität. Schließlich wurden diese Daten im Household Drought Risk Index (HDRI) zusammengeführt, um Orientierungswissen zu generieren und das Dürrerisiko der Haushalte zu bestimmen. Daraus abgeleitetes Transformationswissen ermöglichte dann die Identifizierung geeigneter Risikominderungsstrategien. Die qualitative Erhebung (n = 26) explorierte die Wirkung von Dürren auf die lokalen Lebensbedingungen. Sie eröffnete Einblicke in die Nutzung von Wasserressourcen und die negativen Auswirkungen von Dürren auf die körperliche/geistige Gesundheit, das Familien-/Gemeinschaftslebens sowie den Lebensunterhalts. Bewältigungsmechanismen konnten auf mehreren Ebenen identifiziert werden, vom Haushalt (z.B. Verkauf landwirtschaftlicher Produkte) über die Gemeinde (z.B. Nachbarschaftshilfe) bis hin zur staatlichen Ebene (z.B. Dürrehilfe). Als kritische Wirkpunkte für Dürren wurden Nutzungsmuster von Wasser- und Nahrungsmitteln identifiziert, die einen Haushalt mehr oder weniger anfällig machen. Die interne Kapitalausstattung (Humanes, Soziales, Finanzielles, Physisches und Natürliches) und die infrastrukturelle und institutionelle Ausstattung eines Gebiets bestimmen weiterhin die Fähigkeit eines Haushalts, mit der Dürregefahr umzugehen. Diese Erkenntnisse ermöglichten die Konstruktion des HDRI Indikators, der in den Folgephasen mit entsprechenden Daten bestückt wurde. Zur Erfassung der Dürregefahr wurden drei Dürreindikatoren im Blended Drought Index (BDI) zusammengefasst. Dieser integrierte Dürreindikator berücksichtigt meteorologische und landwirtschaftliche Merkmale, die die Ernährungs- und Wassersicherheit der Bevölkerung beeinträchtigen. Der BDI verwendet eine Copula-Funktion, um gängige Dürreindikatoren zu kombinieren, die auf Niederschlag, Evapotranspiration, Bodenfeuchte und Vegetation zurückgreifen. Fernerkundungsprodukte wurden verarbeitet, um Häufigkeit, Stärke und Dauer der Dürren zu analysieren. Dabei wurden verschiedene Niederschlagsprodukte einer Unsicherheitsanalyse unterzogen, um jenes Produkt zu identifizieren, das am besten mit lokal gemessenen Stationsdaten korrespondiert. Die resultierende, integrierte Dürregefahrenkarte zeigt den Norden der Etosha-Pfanne und das Gebiet entlang des Kunene-Flusses als am stärksten von Dürren bedroht an. Zeitlich korreliert der BDI gut mit den Daten des Hirseertrages (r = 0,51) und dem lokalen Wasserverbrauch (r = -0,45) und übertrifft dabei konventionelle Indikatoren. Die Vulnerabilität wurde anhand von sozioökonomischen Daten aus einer Haushalts-befragung (n = 461) erfasst. Die Nutzungsmuster zeigen einen statistisch signifikanten Schwenk von kritischen Wasser- und Nahrungsquellen (z.B. Brunnen, Subsistenz-produkte) hin zu verlässlichen Quellen (z.B. Leitungswasser, Märkte) während der Trockenzeit. Haushalte mit einer starken Abhängigkeit von kritischen Quellen sind besonders sensitiv gegenüber Dürren. Die Kapitalausstattung der Haushalte variiert v.a. zwischen Land und Stadt sowie zwischen Namibia und Angola. Dabei treten Human- und Finanzkapital gemeinsam mit der infrastrukturellen und institutionellen Raumausstattung als wichtige Kontrollvariablen hervor. Die HDRI Ergebnisse zeigen, dass die angolanische Bevölkerung ein höheres Risiko aufweist, was v.a. durch weniger entwickelte Infrastruktursysteme, schwächere institutionelle- und geringere Bewältigungskapazitäten verursacht wird. Insgesamt gehen Stadtbewohner weniger dürresensitiven Nutzungsmustern nach, sind aber aufgrund familiärer Beziehungen weiterhin mit den ländlichen Gebieten verbunden. Die integrierte, räumliche Risikoabschätzung zeigt Gebiete in Angola und Namibia die sowohl dürregefährdet als auch vulnerabel sind. Die Ergebnisse erlauben zentrale Empfehlungen für Politik und Wissenschaft: Erstens sollte die Dürrebeobachtung im Cuvelai-Becken ein breiteres Spektrum von Indikatoren berücksichtigen und zusätzlich die Verwundbarkeit der Bevölkerung einbeziehen. Dies ermöglicht die Entwicklung von integrierten Dürreinformationssystemen. Zweitens, zur Verringerung der Sensitivität der Bevölkerung müssen lokale Wasserspeicher durch eine verbesserte Wassernutzungseffizienz erhöht werden. Dies gilt sowohl für blaues als auch grünes Wasser. Wassersparende Bewässerungssysteme in Kombination mit dezentralen Regen- und Flutwasserspeichern sind vielversprechende Möglichkeiten. Darüber hinaus müssen zentrale Infrastrukturen der Wasserversorgung und der Marktsysteme ausgebaut werden. Drittens, ist der Zusammenhalt der lokalen Gemeinschaften ein wichtiges institutionelles Rückgrat zur Bewältigung von Dürren und zur Anpassung an künftige Veränderungen. Anstrengungen zur Entwicklung des ländlichen Raums sind erforderlich, die über technische Interventionen hinausgehen und Gemeinschaften durch kollektive Maßnahmen und Ausbildung sowohl in der Wasserwirtschaft als auch der Landwirtschaft unterstützen und so die Lebensgrundlagen von den Niederschlägen entkoppeln

The evaluation of Corona and Ikonos satellite imagery for archaeological applications in a semi-arid environment

Archaeologists have been aware of the potential of satellite imagery as a tool almost since the first Earth remote sensing satellite. Initially sensors such as Landsat had a ground resolution which was too coarse for thorough archaeological prospection although the imagery was used for geo-archaeological and enviro-archaeological analyses. In the intervening years the spatial and spectral resolution of these sensing devices has improved. In recent years two important occurrences enhanced the archaeological applicability of imagery from satellite platforms: The declassification of high resolution photography by the American and Russian governments and the deregulation of commercial remote sensing systems allowing the collection of sub metre resolution imagery. This thesis aims to evaluate the archaeological application of three potentially important resources; Corona space photography and Ikonos panchromatic and multispectral imager). These resources are evaluated in conjunction with Landsat Thematic Mapper (TM) imagery over a 600 square km study area in the semi-arid environment around Homs, Syria. The archaeological resource in this area is poorly understood, mapped and documented. The images are evaluated for their ability to create thematic layers and to locate archaeological residues in different environmental zones. Further consideration is given to the physical factors that allow archaeological residues to be identified and how satellite imagery and modern technology may impact on Cultural Resource Management. This research demonstrates that modern high resolution and historic satellite imagery can be important tools for archaeologists studying in semi-arid environments. The imagery has allowed a representative range of archaeological features and landscape themes to be identified. The research shows that the use of satellite imagery can have significant impact on the design of the archaeological survey in the middle-east and perhaps in other environments

A multiscale perspective of water resources and ecosystem services

Doctor of PhilosophyDepartment of Biological & Agricultural EngineeringStacy L. HutchinsonWater security is one of the greatest challenges of this century. The anthropogenic and environmental demand for water could likely outpace the freshwater availability in the future due to challenges caused by the growing world population, technological and economic advancements, and climate change. The ability to ensure adequate quantities of safe, affordable, and accessible water in the future requires innovative and interdisciplinary approaches to water management using a systems perspective across multiple spatial and temporal scales. This dissertation provides a multi-scale perspective of water resources and associated ecosystem services to understand drivers of change in surface water availability across spatiotemporal scales. The ultimate goal of this work is to advance the development of water security solutions by contributing to the current water resources and ecosystem services knowledge base