Modern control concepts in hydrology

Two approaches to an identification problem in hydrology are presented based upon concepts from modern control and estimation theory. The first approach treats the identification of unknown parameters in a hydrologic system subject to noisy inputs as an adaptive linear stochastic control problem; the second approach alters the model equation to account for the random part in the inputs, and then uses a nonlinear estimation scheme to estimate the unknown parameters. Both approaches use state-space concepts. The identification schemes are sequential and adaptive and can handle either time invariant or time dependent parameters. They are used to identify parameters in the Prasad model of rainfall-runoff. The results obtained are encouraging and conform with results from two previous studies; the first using numerical integration of the model equation along with a trial-and-error procedure, and the second, by using a quasi-linearization technique. The proposed approaches offer a systematic way of analyzing the rainfall-runoff process when the input data are imbedded in noise

Directory of Water Related Courses Offered at Colleges and Universities in Arkansas as of November 1998

This publication lists the water and water-related courses at several universities and colleges in Arkansas as reported during the Fall of 1 998. It is anticipated that users of this directory will extend beyond college students, and will include professionals seeking continuing education, and professors desiring to exchange Information on courses. This directory is not an absolute source of water and water-related courses because all of the higher learning Institutions In Arkansas are not listed, and, secondly, because the definition of water and water-related varies from institution to institution. None-the-less this directory provides a very valuable and impressive reference on water resources courses. Users must remember that course offerings, titles, and content change; therefore, one must contact the department to confirm details about each course. We are very grateful to the many people, too numerous to list, who have cooperated in gathering the Information In this second edition of the directory

A brief history of long memory: Hurst, Mandelbrot and the road to ARFIMA

Long memory plays an important role in many fields by determining the behaviour and predictability of systems; for instance, climate, hydrology, finance, networks and DNA sequencing. In particular, it is important to test if a process is exhibiting long memory since that impacts the accuracy and confidence with which one may predict future events on the basis of a small amount of historical data. A major force in the development and study of long memory was the late Benoit B. Mandelbrot. Here we discuss the original motivation of the development of long memory and Mandelbrot's influence on this fascinating field. We will also elucidate the sometimes contrasting approaches to long memory in different scientific communitiesComment: 40 page

Book notices and Book reviews

Book notices and Book reviews from Volume 1, Number 2, 1967 of Earth Science Journal

Integrative research in the university context: Centre for Resource and Environmental Studies, the Australian National University

At a time of increasing interest and advocacy in integrated and policy-oriented research, this paper offers an empirically-based view of the intellectual and practical challenges of undertaking such research. It analyses the experience of a long-standing university research and postgraduate training centre from 1973-2004: the Centre for Resource and Environmental Studies at The Australian National University. The paper discusses staff development issues, cross-disciplinary understanding, organisational requirements for collaborative research, postgraduate and early career considerations, a range of integrative frameworks, and the tensions that arise for interdisciplinary research in the political and economic operating environments of modern universities

Planning and managing water resources at the river-basin level: emergence and evolution of a concept

River basin development / Legislation / Environmental effects / Water resource management / Watersheds

Modification and preservation of environmental signals in speleothems

Speleothems are primarily studied in order to generate archives of climatic change and results have led to significant advances in identifying and dating major shifts in the climate system. However, the climatological meaning of many speleothem records cannot be interpreted unequivocally; this is particularly so for more subtle shifts and shorter time periods, but the use of multiple proxies and improving understanding of formation mechanisms offers a clear way forward. An explicit description of speleothem records as time series draws attention to the nature and importance of the signal filtering processes by which the weather, the seasons and longer-term climatic and other environmental fluctuations become encoded in speleothems. We distinguish five sources of variation that influence speleothem geochemistry: atmospheric, vegetation/soil, karstic aquifer, primary speleothem crystal growth and secondary alteration and give specific examples of their influence. The direct role of climate diminishes progressively through these five factors. \ud \ud We identify and review a number of processes identified in recent and current work that bear significantly on the conventional interpretation of speleothem records, for example: \ud \ud 1) speleothem geochemistry can vary seasonally and hence a research need is to establish the proportion of growth attributable to different seasons and whether this varies over time. \ud \ud 2) whereas there has traditionally been a focus on monthly mean Ã�´18O data of atmospheric moisture, current work emphasizes the importance of understanding the synoptic processes that lead to characteristic isotope signals, since changing relative abundance of different weather types might 1Corresponding author, fax +44(0)1214145528, E-mail: [email protected] control their variation on the longer-term. \ud \ud 3) the ecosystem and soil zone overlying the cave fundamentally imprint the carbon and trace element signals and can show characteristic variations with time. \ud \ud 4) new modelling on aquifer plumbing allows quantification of the effects of aquifer mixing. \ud \ud 5) recent work has emphasized the importance and seasonal variability of CO2-degassing leading to calcite precipitation upflow of a depositional site on carbon isotope and trace element composition of speleothems. \ud \ud 6) Although much is known about the chemical partitioning between water and stalagmites, variability in relation to crystal growth mechanisms and kinetics is a research frontier. \ud \ud 7) Aragonite is susceptible to conversion to calcite with major loss of chemical information, but the controls on the rate of this process are obscure. \ud \ud Analytical factors are critical to generate high-resolution speleothem records. A variety of methods of trace element analysis are available, but standardization is a common problem with the most rapid methods. New stable isotope data on Irish stalagmite CC3 compares rapid laser-ablation techniques with the conventional analysis of micromilled powders and ion microprobe methods. A high degree of comparability between techniques for Ã�´18O is found on the mm-cm scale, but a previously described high-amplitude oxygen isotope excursion around 8.3 ka is identified as an analytical artefact related to fractionation of the laser-analysis associated with sample cracking. High-frequency variability of not less than 0.5o/oo may be an inherent feature of speleothem Ã�´18O records

Initial Hydraulic modelling and Levee Stability Analysis of the Triple M Ranch Restoration Project

“Advanced Watershed Science and Policy (ESSP 660)” is a graduate class taught in the Master of Science in Coastal and Watershed Science & Policy program at California State University Monterey Bay (CSUMB). In 2007, the class was taught in four 4-week modules, each focusing on a local watershed issue. This report is one outcome of one of those 4-week modules taught in the fall 2007 session. (Document contains 32 pages

Models of everywhere revisited: a technological perspective

The concept ‘models of everywhere’ was first introduced in the mid 2000s as a means of reasoning about the environmental science of a place, changing the nature of the underlying modelling process, from one in which general model structures are used to one in which modelling becomes a learning process about specific places, in particular capturing the idiosyncrasies of that place. At one level, this is a straightforward concept, but at another it is a rich multi-dimensional conceptual framework involving the following key dimensions: models of everywhere, models of everything and models at all times, being constantly re-evaluated against the most current evidence. This is a compelling approach with the potential to deal with epistemic uncertainties and nonlinearities. However, the approach has, as yet, not been fully utilised or explored. This paper examines the concept of models of everywhere in the light of recent advances in technology. The paper argues that, when first proposed, technology was a limiting factor but now, with advances in areas such as Internet of Things, cloud computing and data analytics, many of the barriers have been alleviated. Consequently, it is timely to look again at the concept of models of everywhere in practical conditions as part of a trans-disciplinary effort to tackle the remaining research questions. The paper concludes by identifying the key elements of a research agenda that should underpin such experimentation and deployment