9 research outputs found
MODELLING WATER AND ENERGY BALANCE OF THE LAND-ATMOSPHERE SYSTEM USING HIGH RESOLUTION REMOTE SENSING DATA
La rilevanza assunta dal risparmio della risorsa idrica negli ultimi anni
ha spinto verso una corretta quanti cazione delle perdite legate al processo
evapotraspirativo, al ne di una gestione parsimoniosa della risorsa stessa.
In particolare nei sistemi agricoli soggetti a stress severo, sia la misura che
la stima dell'evapotraspirazione (ET) ad un'adeguata risoluzione spaziale
e temporale sono uno dei principali problemi da a rontare per la comunit a
scienti ca. Recentemente, le tecniche di telerilevamento sono divenute un
ulteriore strumento a supporto della modellistica idrologica distribuita; in
particolare, le immagini acquisite nelle onde corte e nell'infrarosso termico
risultano essere di notevole interesse. In questo contesto, i due scopi principali
di questa ricerca sono stati: la quanti cazione dell'accuratezza delle
misure micro-meteorologiche in sistemi agricoli vegetati con colture alte e
sparse; e l'analisi dei modelli basati su dati telerilevati per la stima di ET
ad alta risoluzione spaziale e temporale. L'area di studio e caratterizzata
da un tipico clima Mediterraneo e da colture olivicole, e si trova localizzata
nei pressi di Castelvetrano (Italia). Quest'area e stata oggetto nella
primavera-estate 2008 di una campagna di misura mediante istallazioni
eddy covariance e scintillometrica, e, contestualmente, dall'acquisizione
di 7 immagini multi-spettrali ad alta risoluzione. L'analisi delle misure
micro-meteorologiche ha permesso di quanti care l'accordo tra le due tecniche
e ha portato allo sviluppo di un nuovo approccio di calibrazione dei
dati scintillometrici. Inoltre, alcune ipotesi alla base della stima dei
ussi
giornalieri sono state discusse in dettaglio. L'analisi degli algoritmi per la
simulazione dei processi di scambio nel continuo suolo-pianta-atmosfera e
stata focalizzata: i) sulle stime hot-spot di ET mediante un approccio di
bilancio energetico residuale, ii) sulla stima in continuo di ET alla scala
di campo mediante diversi approcci. Quest'ultima analisi ha evidenziato i
buoni risultati del modello accoppiato energetico/idrologico per la stima
dei
ussi di acqua ed energia sia a scala oraria che giornaliera. In ne, l'applicabilit
a di due approcci di data assimilation e stata testata utilizzando
sia osservazioni arti ciali che reali.In view of the increased relevance of water saving issues in the last
decades, the correct quanti cation of water loss due to evapotranspirative
process became fundamental for a parsimonious management of this
resource. Especially in agricultural systems subjected to severe water
stress, both the measurement and the modelling of evapotranspiration
(ET) at adequate temporal and spatial resolution, are important topics
for the hydrologist scienti c community. Recently, the remote sensing
techniques provide an additional tool to support the hydrologic spatially
distributed models; in particular, images acquired in the short-wave and
the thermal spectral regions have quite interesting applications. Within
this framework, the two principal aims of this work were: to quantify
the accuracy of surface energy
uxes measured by micro-meteorological
techniques in sparse tall vegetated system; and to analyze the capability
of remote sensing-based approach to retrieve ET at high temporal and
spatial resolution. The selected test site was an area characterized by
Mediterranean climate and olive crops, located near Castelvetrano (Italy).
This area, during the spring-summer period in 2008, was interested by
in-situ measurements campaigns with eddy covariance and scintillometer
instruments, and, contextually, by the acquisition of 7 high resolution
multi-spectral images. The analysis of micro-meteorological measurements
allows to evaluate the agreement between these techniques in the study
site, also by means of a novel algorithm for the elaboration of scintillometer
data. Moreover, some fundamental hypothesis of daily
uxes estimation
was critically discussed. The analysis of the algorithms for the simulation
of the exchange processes in the continuum soil-plant-atmosphere was focused
on: i) the retrieval of hot-spot ET maps by means of residual energy
balance approach and ii) the continuous ET estimation at eld scale using
di erent approaches. This latter analysis highlights the good performance
of a coupled energy/hydrological model for the assessment of energy and
water
uxes at both hourly and daily scale. Finally, the applicability of
two data assimilation schemes was tested using both arti cial and real
observations
Rainfall-Runoff Modelling in Arid Areas
Arid areas have distinctive hydrological features substantially different from those of humid areas. The high temporal and spatial distribution of the ra;infall, flash floods, absence of base flow, sparsity of plant cover, high transmission losses, high amounts of evaporation and evapotranspiration and the general climatologies are examples of such differences. The aim of this Ph.D. research is to use advanced tools of model analysis to test some of the current models that consider arid area hydrological characteristics. As most models were mainly developed for other regions, an attempt is made to study their limitations using Omani hydrological data, providing some guidelines for improved rainfall-runoff modelling in arid areas in general and Oman in particular. Two different types of models were selected for this research; KINEROS, which is an event based, semi-distributed, physically-based model that is considered suitable to be used for arid area conditions, and, which is continuous, lumped, conceptual model. Two Omani catchments were selected to test the performance of the selected models and to identify the main uncertainties arising, to provide some recommendations regarding the suitability of these models or model types and how they might be improved, to highlight any further data that is required, and how uncertainties should be handled in model applications.Imperial Users onl
TERSSE: Definition of the Total Earth Resources System for the Shuttle Era. Volume 2: An Assessment of the Current State-of-the-Art
Results of a state-of-the-art assessment of technology areas which affect the Earth Resources Program are presented along with a functional description of the basic earth resources system. Major areas discussed include: spacecraft flight hardware, remote sensors, data processing techniques and hardware, user models, user interfaces, and operations technology
Soil Water Erosion
The purpose of this book is to provide novel results related to soil water erosion that could help landowners and land-users, farmers, politicians, and other representatives of our global society to protect and, if possible, improve the quality and quantity of our precious soil resources. Published papers on the topics are related to new ways of mapping, maps with more detailed input data, maps about areas that have never been mapped before, sediment yield estimations, modelling sheets and gully erosion, USLE models, RUSLE models, dams which stop sediment runoff, sediment influx, solute transport, soil detachment capacities, badland morphology, freeze-thaw cycles, armed conflicts, use of rainfall simulators, rainfall erosivity, soil erodibility, etc
Development of Semantics-Based Distributed Middleware for Heterogeneous Data Integration and its Application for Drought
ThesisDrought is a complex environmental phenomenon that affects millions of people and communities all over the globe and is too elusive to be accurately predicted. This is mostly due to the scalability and variability of the web of environmental parameters that directly/indirectly causes the onset of different categories of drought. Since the dawn of man, efforts have been made to uniquely understand the natural indicators that provide signs of likely environmental events. These indicators/signs in the form of indigenous knowledge system have been used for generations. Also, since the dawn of modern science, different drought prediction and forecasting models/indices have been developed which usually incorporate data from sparsely located weather stations in their computation, producing less accurate results – due to lack of the desired scalability in the input datasets.
The intricate complexity of drought has, however, always been a major stumbling block for accurate drought prediction and forecasting systems. Recently, scientists in the field of ethnoecology, agriculture and environmental monitoring have been discussing the integration of indigenous knowledge and scientific knowledge for a more accurate environmental forecasting system in order to incorporate diverse environmental information for a reliable drought forecast. Hence, in this research, the core objective is the development of a semantics-based data integration middleware that encompasses and integrates heterogeneous data models of local indigenous knowledge and sensor data towards an accurate drought forecasting system for the study areas of the KwaZulu-Natal province of South Africa and Mbeere District of Kenya.
For the study areas, the local indigenous knowledge on drought gathered from the domain experts and local elderly farmers, is transformed into rules to be used for performing deductive inference in conjunction with sensors data for determining the onset of drought through an automated inference generation module of the middleware. The semantic middleware incorporates, inter alia, a distributed architecture that consists of a streaming data processing engine based on Apache Kafka for real-time stream processing; a rule-based reasoning module; an ontology module for semantic representation of the knowledge bases. The plethora of sub-systems in the semantic middleware produce a service(s) as a combined output – in the form of drought forecast advisory information (DFAI). The DFAI as an output of the semantic middleware is disseminated across multiple channels for utilisation by policy-makers to develop mitigation strategies to combat the effect of drought and their drought-related decision-making processes
Environmental Governance in Indonesia
Indonesia is one of the countries with the fastest-growing economies in Asia and one of the most biologically diverse countries in the world. With ecosystems ranging from terrestrial to marine and teemed with unique life forms, Indonesia is rich in natural resources. Unfortunately, Indonesia also suffers from overexploitation and environmental threats exacerbated by climate and human pressures. Along with the growing global ambitions for achieving sustainable development and increasing its capacity to adapt to climate change and extreme events, Indonesia is also increasing its commitments to balance development while safeguarding environmental and social sustainability. However, challenges remain, especially on how to effectively govern the responses to environmental issues. Against this background, this book will present state-of-the-art environmental governance research and practices in Indonesia. It offers a wide scope, covering different themes and sectors (e.g., climate change, disaster risk, forestry, mining, etc.), diverse physical and societal landscapes (e.g., urban, rural, deltas, coastal areas, etc.), and multiscalar perspectives (from national to local level). This book has the ambition to incorporate more knowledge to indicate research gaps and future directions for environmental governance research. Our intention is also to reflect a vision to make the national and global environmental governance research agenda to be more diverse, inclusive, interdisciplinary, and transdisciplinary. We hope that this book will be useful for researchers, students, practitioners, and policymakers who are interested in the field of environmental governance, especially in Indonesia as a megadiversity country that encompasses the world’s largest archipelago