Can simple phosphorus mass balance models guide management decisions? A case study in the Bay of Quinte, Ontario, Canada

2013 ◽  
Vol 257 ◽  
pp. 66-79 ◽  
Author(s):  
Weitao Zhang ◽  
Dong-Kyun Kim ◽  
Yerubandi R. Rao ◽  
Sue Watson ◽  
Shan Mugalingam ◽  
...  
2013 ◽  
Vol 256 ◽  
pp. 53-68 ◽  
Author(s):  
Dong-Kyun Kim ◽  
Weitao Zhang ◽  
Yerubandi R. Rao ◽  
Sue Watson ◽  
Shan Mugalingam ◽  
...  

2009 ◽  
Author(s):  
A. Gentile ◽  
L. Pierce ◽  
G. Ciraolo ◽  
G. Zhang ◽  
G. La Loggia ◽  
...  

2021 ◽  
Author(s):  
Hamed Khorasani ◽  
Zhenduo Zhu

<p>Phosphorus (P) is the key and limiting nutrient in the eutrophication of freshwater resources. Modeling P retention in lakes using steady-state mass balance models (i.e. Vollenweider-type models) provides insights into the lake P management and a simple method for large-scale assessments of P in lakes. One of the basic problems in the mass balance modeling of P in lakes is the removal of P from the lake water column by settling. A fraction of the incoming P into the lake from the watershed is associated with fast-settling particles (e.g. sediment particles) that result in the removal of that fraction of P quickly at the lake entrance. However, existing models considering a constant fraction of fast-settling TP for all lakes are shown to result in overestimation of the retention of P in lakes with short hydraulic residence time. In this study, we combine a hypothesis of the fast- and slow-settling P fractions into the steady-state mass balance models of P retention in lakes. We use a large database of lakes to calibrate the model and evaluate the hypothesis. The results of this work can be used for the improvement of the prediction power of P retention models in lakes and help to better understand the processes of P cycling in lakes.</p>


2015 ◽  
Vol 8 (2) ◽  
pp. 167-181
Author(s):  
Roxana Popa Strainu ◽  
Mircea Georgescu

AbstractA system built to support management decisions and not only needs to be accurate and well adapted to the requirements of the decision and the variables involved in it, and this happens because a decision is still a human act in any type of business and institution. We can say that a decision support system has a part in it that cannot be determined by any software: the human decision which is not a determinist act. It depends on a lot of variables but also still involves the decision maker intuition and experience. This is why an important problem emerged to be discussed in this paper: the need to implement and develop an in house solution to help management decisions and not only, using existing tools and this with no additional fees. This can be a good opportunity to discover models and solutions. An identified solution using Microsoft Excel and Access is discussed in this paper and a model applied on a case study will be presented. The results of the case study showed a real support in making decisions and a better transparency in manipulating the data, improving also the time needed to collect, transform and present data. The model can be applied in any type of problem that needs a visual presentation of data as well as in situations that need working with a large amount of data, but especially in small and medium size companies.


2021 ◽  
Author(s):  
Lilian Schuster ◽  
David Rounce ◽  
Fabien Maussion

<p>A recent large model intercomparison study (GlacierMIP) showed that differences between the glacier models is a dominant source of uncertainty for future glacier change projections, in particular in the first half of the century.  Each glacier model has their own unique set of process representations and climate forcing methodology, which makes it impossible to determine the model components that contribute most to the projection uncertainty. This study aims to improve our understanding of the sources of large scale glacier model uncertainty using the Open Global Glacier Model (OGGM), focussing on the surface mass balance (SMB) in a first step. We calibrate and run a set of interchangeable SMB model parameterizations (e.g. monthly vs. daily, constant vs. variable lapse rates, albedo, snowpack evolution and refreezing) under controlled boundary conditions. Based on ensemble approaches, we explore the influence of (i) the parameter calibration strategy and (ii) SMB model complexity on regional to global glacier change. These uncertainties are then put in relation to a qualitative selection of other model design choices, such as the forcing climate dataset and ice dynamics model parameters. </p>


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