This model provides a dynamic simulation of the Sverdrup (1953) paper on the vernal blooming of phytoplankton.  The model simulates the dynamics of the mixed layer over the year, and illustrates how it's depth variation leads to conditions that trigger the spring bloom. In order for the bloom to occ
This model provides a dynamic simulation of the Sverdrup (1953) paper on the vernal blooming of phytoplankton.

The model simulates the dynamics of the mixed layer over the year, and illustrates how it's depth variation leads to conditions that trigger the spring bloom. In order for the bloom to occur, production of algae in the water column must exceed respiration.

This can only occur if vertical mixing cannot transport algae into deeper, darker water, for long periods, where they are unable to grow.

Sverdrup, H.U., 1953. On conditions for the vernal blooming of phytoplankton. J. Cons. Perm. Int. Exp. Mer, 18: 287-295
Two households with PV systems and Electric Vehicles, sharing a battery and connected to the grid. What are the advantages?
Two households with PV systems and Electric Vehicles, sharing a battery and connected to the grid. What are the advantages?


This model represents a broad overview of the hydrological system of Lake Okeechobee and its surrounding areas of SWFL.
This model represents a broad overview of the hydrological system of Lake Okeechobee and its surrounding areas of SWFL.
This model describes the flow of energy from generation to consumption for neighborhoods in the metro Atlanta area. It also calculates the cost of energy production and the number of years it will take to recover that cost.
This model describes the flow of energy from generation to consumption for neighborhoods in the metro Atlanta area. It also calculates the cost of energy production and the number of years it will take to recover that cost.
This is a simulation that represents the populations of lions in the world over the last 200 years.
This is a simulation that represents the populations of lions in the world over the last 200 years.
 
 Adapted from Fig 13.1 p.523 of the Book: James A. Forte ( 2007),  Human Behavior and The Social Environment: Models, Metaphors and Maps for Applying Theoretical Perspectives to Practice   Thomson Brooks/Cole Belmont ISBN 0-495-00659-9

Adapted from Fig 13.1 p.523 of the Book: James A. Forte ( 2007), Human Behavior and The Social Environment: Models, Metaphors and Maps for Applying Theoretical Perspectives to Practice  Thomson Brooks/Cole Belmont ISBN 0-495-00659-9

7 months ago
This model illustrates predator prey interactions using real-life data of wolf and moose populations on the Isle Royale.  We incorporate logistic growth into the moose dynamics, and we replace the death flow of the moose with a kill rate modeled from the kill rate data found on the Isle Royale websi
This model illustrates predator prey interactions using real-life data of wolf and moose populations on the Isle Royale.

We incorporate logistic growth into the moose dynamics, and we replace the death flow of the moose with a kill rate modeled from the kill rate data found on the Isle Royale website.

I start with these parameters:
Wolf Death Rate = 0.15
Wolf Birth Rate = 0.0187963
Moose Birth Rate = 0.4
Carrying Capacity = 2000
Initial Moose: 563
Initial Wolves: 20

I used RK-4 with step-size 0.1, from 1959 for 60 years.

The moose birth flow is logistic, MBR*M*(1-M/K)
Moose death flow is Kill Rate (in Moose/Year)
Wolf birth flow is WBR*Kill Rate (in Wolves/Year)
Wolf death flow is WDR*W

Federal  University  UFRN  , Brazil   chemical  Engineering  Analysis of Environmental Systems  solid  residuos   for northeat brasil
Federal  University  UFRN  , Brazil   chemical  Engineering 
Analysis of Environmental Systems  solid  residuos   for northeat brasil

Simple energy balance model of a planet with albedo, ocean, and atmosphere.  This simulation models the stock and flow of energy between a
star, a planet’s surface (primarily its oceans, which are the largest reservoir
of heat), and space.The assumptions governing this model are:  1. The planet abso
Simple energy balance model of a planet with albedo, ocean, and atmosphere.

This simulation models the stock and flow of energy between a star, a planet’s surface (primarily its oceans, which are the largest reservoir of heat), and space.The assumptions governing this model are:

1. The planet absorbs a fraction of the shortwave radiation arriving from its star, with that fraction given by (1-A), where A is albedo. 

2. The planet radiates longwave infrared radiation into space, with the amount of radiation into space given by σΤe4, where σ is the Stefan-Boltzmann constant and Te is the temperature of the effective radiating level.

3. The atmospheric lapse rate is 6 K/km.

4. If there is an imbalance between shortwave radiation absorbed and longwave radiation emitted, the imbalance affects the temperature of the planet. However, it does not do so instantaneously – the imbalance must heat or cool the mixed layer of the ocean.

5. At the start of the simulation, the planet is extremely close to equilibrium given its default parameters. If any of these parameters are changed, the planet will be out of equilibrium, and will have to adjust.

 Students in ENVS 270 Online at the University of Arizona: please click Clone Insight at the top to make an editable copy of this model.    As initially proposed by Pr. William M White of Cornell University:    http://www.geo.cornell.edu/eas/education/course/descr/EAS302/302_06Lab11.pdf    http://ww
Students in ENVS 270 Online at the University of Arizona: please click Clone Insight at the top to make an editable copy of this model.

As initially proposed by Pr. William M White of Cornell University:
 The model starts in 1900. In the year 2000 you get the chance to set a new emission target and nominal time to reach it. Your aim is to have atmospheric CO2 stabilise at about 400 ppmv in 2100.  From Sterman, John D. (2008)  Risk Communication on Climate:  Mental Models and Mass Balance.  Science 3
The model starts in 1900. In the year 2000 you get the chance to set a new emission target and nominal time to reach it. Your aim is to have atmospheric CO2 stabilise at about 400 ppmv in 2100.  From Sterman, John D. (2008)  Risk Communication on Climate:  Mental Models and Mass Balance.  Science 322 (24 October): 532-533. Older version of IM-9283.
 This story presents a conceptual model of nitrogen cycling in a dune-lake system in the Northland region of New Zealand. It is based on the concept of a stock and flow diagram. Each orange ellipse represents an input, while each blue box represents a stock. Each arrow represents a flow. A flow invo

This story presents a conceptual model of nitrogen cycling in a dune-lake system in the Northland region of New Zealand. It is based on the concept of a stock and flow diagram. Each orange ellipse represents an input, while each blue box represents a stock. Each arrow represents a flow. A flow involves a loss from the stock at which it starts and an addition to the stock at which it ends.

 Clone pannirbrof Biogas to Energy | Insight Maker  https://insightmaker.com/insight/114792/Clone-pannirbrof-Biogas-to-Energy   Simple mass balance model for lakes, based on the Vollenweider equation:  dMw/dt = Min - sMw - Mout  The model was first used in the 1960s to determine the phosphorus conce
Clone pannirbrof Biogas to Energy | Insight Maker https://insightmaker.com/insight/114792/Clone-pannirbrof-Biogas-to-Energy 
Simple mass balance model for lakes, based on the Vollenweider equation:

dMw/dt = Min - sMw - Mout

The model was first used in the 1960s to determine the phosphorus concentration in lakes and reservoirs, for eutrophication assessment.


Ecocity model , Joanna