WGEN Weather Simulator

Jason

June 13, 2022 21:44
Updated

WGEN is a stochastic weather generator originally developed in the 1980s in Fortran at the US Department of Agriculture Agricultural Research Service (Richardson and Wright 1984). It uses monthly and annual statistics to generate daily time series of precipitation, minimum temperature, maximum temperature, and solar radiation.

Use the WGEN PAR model to generate the parameter inputs for this model.

Download the Model File:

Comments

17 comments

Jason

January 04, 2019 19:32
Model version 1.015 released on 4 Jan, 2019

Version Report
1. Added clarification to some element descriptions
2. Changed the random number generator for determining wet/dry states in the Markov model from a Random Choice element to a stochastic with Uniform distribution.
3. Added ability to override the random numbers with a user-defined value for the purposes of validation, if it is needed (so you can predict the outcome).
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Jason

January 11, 2019 18:46

Edited
Model version 1.020 released on 11 Jan, 2019

Version Report
1. Corrected the label for observed rain, which was mislabeled as "observed radiation" and placed in the radiation portion of the inputs. This change doesn't affect the model output.
2. Hard-code in deterministic values so that user only needs to turn it on or off to debug in deterministic mode
3. Minor clarifications in documentation of temperature calculations
4. Some textbooks define the scale factor for the gamma distribution differently. Some use the notation of lambda and this is 1/beta. Clarified in the documentation.
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Jason

January 26, 2019 00:14

Edited
Model version 1.024 released on 25 Jan, 2019

Version Report

The harmonic value "x" in the temperature container should have an initial condition of vector(0) unless you are running it deterministically for verification purposes. This has been fixed using an IF statement:

if(Temp_Determ, vector(-0.3513, -1.754, 0.6244), vector(0))

Where "Temp_Determ" is set to False by default. Only set this to True if you need to run a deterministic validation run.

I was using a Random Choice element for determining the wet/dry state but it's not possible to use this if you want to switch to a deterministic run for validation. I rolled this back to an earlier version of the markov function that uses a stochastic with uniform distribution instead. This is how the FORTRAN code is implemented.
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Jason

February 08, 2019 00:28
Model version 1.025 released on 7 Feb, 2019

Version Report
1. Fixed random number generator in markov rain model. The stochastic element used to generate random numbers in the rainfall container was not set to trigger daily. The trigger was added.
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Jason

March 06, 2019 18:03
Model version 1.026 released on 6 Mar, 2019

Version Report
1. Precipitation chart was missing from the dashboard. This Result was added back in and placed on the dashboard.
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Jason

May 13, 2019 21:00
Model version 1.029 released on 13 May, 2019

Version Report:

1. Added support for units so that data can be entered in terms of metric or English units.

2. Added results to support the differences in units
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Jason

September 11, 2019 22:26

Edited
Model version 1.031 released on 11 September, 2019

Version Report:
1. The x axis for the top 2 charts on the dashboard is redundant because the bottom chart axis can apply to all 3. Removed x axis on top to charts.
2. Changed the title shown on the dashboard.
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Jason

December 17, 2019 22:58
Model version 1.035 released on 17 December, 2019

Version Report:
1. Applied units to main outputs (precip, min/max temp, and radiation)
2. Result plots were updated
3. Verification tests and charts were updated with units change
These changes did not affect the underlying calculations in any way but make it easier to port the model to another model, which will need to carry those unit dimensions forward.
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Natalia Vieira

July 05, 2021 19:07
hi! i can't download de WGEN PAR model, can you please help me?
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Jason

July 06, 2021 15:02
Natalia,

Can you tell me what happens when you attempt to download that model? Here is the link to the article with the download link at the bottom: WGEN Parameter Generator – GoldSim Help Center
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Fernando Laqui

December 20, 2021 20:14
hi jason, how could i modify the input parameters manually. Since it is currently only as reading
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Rafay Sheraz

February 10, 2022 09:15
sir kindly guide how to download and start this WGEN generator model in my laptop.
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Jason

February 10, 2022 16:43
@fernando, you should be able to enter values on the dashboard manually. Are you having trouble doing so?
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Jason

February 10, 2022 16:44
@Rafay,

You need a GoldSim software license to use this model. If you are a student, you can apply for a free academic license from here: GoldSim Academic Application Form - GoldSim
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Rafay Sheraz

June 04, 2022 09:37
Currently I am facing this error while running the model. please guide me how to resolve it.
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Jason

June 06, 2022 23:21
Rafay,

As per our discussion in our support ticket, it appears the issue was resolved by changing the name of 1 or more of the sheets in your Excel file. Is that right?

-Jason
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Jason

June 13, 2022 21:44

Edited
Version Report:

Version 1.045
1. Fixed an issue that occurs when dealing with negative temperature values. Convert all temperature data to Kelvin on the front end before performing all calculations. Outputs are converted back from Kelvin on the back end.
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