History Of Model Development Research Articles

A retrospective on hydrological catchment modelling based on half a century with the HBV model

Abstract. Hydrological catchment models are important tools that are commonly used as the basis for water resource management planning. In the 1960s and 1970s, the development of several relatively simple models to simulate catchment runoff started, and a number of so-called conceptual (or bucket-type) models were suggested. In these models, the complex and heterogeneous hydrological processes in a catchment are represented by a limited number of storage elements and the fluxes between them. While computer limitations were a major motivation for such relatively simple models in the early days, some of these models are still used frequently despite the vast increase in computational opportunities. The HBV (Hydrologiska Byråns Vattenbalansavdelning) model, which was first applied about 50 years ago in Sweden, is a typical example of a conceptual catchment model and has gained large popularity since its inception. During several model intercomparisons, the HBV model performed well despite (or because of) its relatively simple model structure. Here, the history of model development, from thoughtful considerations of different model structures to modelling studies using hundreds of catchments and cloud computing facilities, is described. Furthermore, the wide range of model applications is discussed. The aim is to provide an understanding of the background of model development and a basis for addressing the balance between model complexity and data availability that will also face hydrologists in the coming decades.

Computational fluid dynamics simulation of snowdrift around buildings: Past achievements and future perspectives

This paper reviews the current status of computational fluid dynamics (CFD) modeling of snowdrift around buildings and discusses the review findings to give insight into future applications. First, an overview of past achievements in CFD simulations of snowdrift around buildings is provided by reviewing previous research. The history of model development is briefly outlined. Next, recent application examples are presented with respect to several topics, i.e., the application to practical design, consideration of meteorological influences and prediction of roof snow. Finally, the remaining development issues and new challenges are presented from an engineering viewpoint. Necessities of further model development, validation database, best practical guidelines and advanced analysis using CFD results are demonstrated. Clearly, CFD has considerable potential, as established in this review. However, to use it appropriately, sufficient attention should be paid to modeling theory and implementation. Because snowdrift is a highly complex phenomenon, we should not excessively rely on numerical simulation. It is important to use data from actual phenomena for all aspects of study.

Microbiological fermentation of lignocellulosic biomass: current state and prospects of mathematical modeling

The anaerobic fermentation process has achieved growing importance in practice in recent years. Anaerobic fermentation is especially valuable because its end product is methane, a renewable energy source. While the use of renewable energy sources has accelerated substantially in recent years, their potential has not yet been sufficiently exploited. This is especially true for biogas technology. Biogas is created in a multistage process in which different microorganisms use the energy stored in carbohydrates, fats, and proteins for their metabolism. In order to produce biogas, any organic substrate that is microbiologically accessible can be used. The microbiological process in itself is extremely complex and still requires substantial research in order to be fully understood. Technical facilities for the production of biogas are thus generally scaled in a purely empirical manner. The efficiency of the process, therefore, corresponds to the optimum only in the rarest cases. An optimal production of biogas, as well as a stable plant operation requires detailed knowledge of the biochemical processes in the fermenter. The use of mathematical models can help to achieve the necessary deeper understanding of the process. This paper reviews both the history of model development and current state of the art in modeling anaerobic digestion processes.

History of model development at Temple, Texas

Model development at Temple, Texas, USA has a long history. Prior to the actual model development research, a hydrological data collection programme was established at Riesel, Texas (about 60 km northeast of Temple) in 1937. Data collected from the Riesel watersheds during 1937–2006 have been valuable in developing and testing models at Temple, as well as at other locations. Actual modelling research began in the mid-1960s with the development of single event models that served as building blocks for the comprehensive models of today. The focus of the early models was on surface water hydrology (rainfall excess, unit hydrographs and flood routing) and sediment yield. The models currently supported at Temple (ALMANAC, EPIC, APEX and SWAT) are continuous and operate on spatial scales ranging from individual fields to river basins. These models have been used worldwide in many projects dealing with soil and water resources and environmental management.

Progress in the development and application of climate ocean models and ocean-atmosphere coupled models in China

A review is presented about the development and application of climate ocean models and oceanatmosphere coupled models developed in China as well as a review of climate variability and climate change studies performed with these models. While the history of model development is briefly reviewed, emphasis has been put on the achievements made in the last five years. Advances in model development are described along with a summary on scientific issues addressed by using these models. The focus of the review is the climate ocean models and the associated coupled models, including both global and regional models, developed at the Institute of Atmospheric Physics, Chinese Academy of Sciences. The progress of either coupled model development made by other institutions or climate modeling using internationally developed models also is reviewed.

Acoustic backscatter models of fish: Gradual or punctuated evolution

Sound-scattering characteristics of aquatic organisms are routinely investigated using theoretical and numerical models. Development of the inverse approach by van Holliday and colleagues in the 1970s catalyzed the development and validation of backscatter models for fish and zooplankton. As the understanding of biological scattering properties increased, so did the number and computational sophistication of backscatter models. The complexity of data used to represent modeled organisms has also evolved in parallel to model development. Simple geometric shapes representing body components or the whole organism have been replaced by anatomically accurate representations derived from imaging sensors such as computer-aided tomography (CAT) scans. In contrast, Medwin and Clay (1998) recommend that fish and zooplankton should be described by simple theories and models, without acoustically superfluous extensions. Since van Holliday’s early work, how has data and computational complexity influenced accuracy and precision of model predictions? How has the understanding of aquatic organism scattering properties increased? Significant steps in the history of model development will be identified and changes in model results will be characterized and compared. [Work supported by ONR and the Alaska Fisheries Science Center.]

Wastewater Treatment Process Theory and Practice: The Emerging Convergence

The state of development of process modeling is assessed from the practitioner's point of view. The history of model development and application within a consulting firm is described. The utility of currently available models is portrayed for the commonly used biological treatment processes. The perspective given is one of assessing model usefulness in its most practical context, that of its utility in a design practice. Areas are identified where additional research and model development are needed.