Weekly Report 6
Monday 06/24 to Wednsday 07/03
Week 5 Objectives
- The focus is still on the Climate-Crop Model
- Get clear about the meaning of main parameres of SIMPLE model
- find the basis of parameters of SIMPLE model in order to be able to collect new records for the local area.
- Alternative
Week05 Tasks
- Look for the code source of the SIMPLE model (As the author has mentioned the model is available on R, Excel and as part of DSSAT)
- In the SIMPLE model:
- Research reliablity and replicabality of \(f(water)\) calculation, \[f(Water) = 1 - S_{water} \times ARID\]
\[ARID = 1 - \dfrac{(min(ET_o,0.096*PAW))}{ET_o}\]
Finding: The best guess for the calculation of PAW was the algorithm provided in a GitHub repo:
Prompt1: for the effect of water on the potential RUE, the model has used a equation that is mentioned is followed by previous model ,but has not provided specific reference. We have to take action for this issue: Option 1: Cancel using SIMPLE model and go to main, widely accepted crop models: A. APSIM: (prefered) for the modular structure and the renewed framework. The more customizable structure makes it more used in the research literature.
B. DSSAT: It is a widely used model for government and ngo activities. The GUI is said to make the use more comfortable. At the first look it seemed too much complex in terms of the inputs required especially in the soil and management input sections.
My approach for next step: Study APSIM: - List the exact simulation requirements - Download the sofware - Put the current collected data + available APSIM default data(for the still unavailable data) and run the initial simulation.
DSSAT: I have submited my request to download the DSSAT model. I will take a deeper view at the strucure as the secondary priority.
For the ETo I have found two major source of calculation: - Priestly-Taylor - Penmann-Monteith
And also two site-based sources that collect meteorological data nearby the study area (i.e. Navajo Nation) - AZMET : The Arizona Meteorological Network provided by the University of Arizona - Utah Climate Center
Prompt2: Calcuate or Collect? - Comment: We should compare them later Insight: These site are a good source to bias-correct or downscaled data from NEX-GDDP_CMIP6
Where does S_water come from? No evidence found: Just the DSSAT is the last hope to find some trace of it.
Where S_co2 come from? I have not processed the task yet
Overall: Is the SIMPLE the one that I should mention as the reference for the crop module of the research IAM model?
Insights
In the SIMPLE model:
1. How the F(water) is calculated?
The equation:
To be able to calculate the F(water function) we should have data for
1. Where does S_water come from?
1. Where S_co2 come from?
1. Overall: Is the SIMPLE the one that I should mention as the reference for the crop module of the research IAM model? - Research on Sco2: Where does it come from and how can we relly on it?
- f_water function. Build it.
- is Topt a funtion of CO2?
Write a report about it: - Test data from input-output of this simplified model to other models and see what is the difference and what is the similarity.
Michael’s side: maintain economic data from the Navajo Nation for a more informed modeling.
New Section: Research Decision Prompts
In the research process, some challenges may appear and to keep the progress, we have to solve them by taking one of the available approaches. We have to keep record of them and we will be able to adjust the research path in the future, when we reach out to some new information. A complete list of these prompts will be included in the model design document.
We will list the propmts that appear in the research process and here is the instructions to pass them: - Describe how the prompt interupts the reseach and what is the accurate question which we are required to clearly answer to.
- Provide the options to pass the question and keep on to the research progress. - For each option, give a description, and a list of pros and cons and provide next steps after we take them as the selected approach.
Propmt: ET0 calculation: - Priestly-Taylor Method: - It is a simplified version of the Penman-Montieth model. - Why to choose this: - It is the one mentioned in the (Simple?) model.
- It not requiring - Penman-Montieth Method:
To forecast the crop output (as the part of our IAM model) we have to choose the strategy:
- Use a customized code that is a combination of existing crop models
- By taking this step we have to select the models that we are including in the code and we have to provide evidence that this code is reliable. SIMPLE Model
Findings
Calculating f(water):
the function: \(f(Water) = 1 - S_{water} \times ARID\)
Zhao et al. (2019) mentions the \(f(Water\)) formula is based on Woli et al. (2012). And the calculation of reference evapotranspiration (\(E_{o}\)) is from Priestley and Taylor (1972).
However, Woli et al. (2012) on its own uses the Penman–Monteith model mentioned in Allen et al. (1998) (FAO Penman Monteith method) for the \(ET_{o}\) which provides a more complex version of what Priestley and Taylor (1972) delivers.
Let’s see the implantation of Priestley and Taylor (1972) first: \(ET_0 = \alpha (R - G) \frac{\Delta}{\Delta + \gamma}\)
[ ET_0 = (R - G) ]
\(\alpha\) is set 1.26 (HEC-HMS Technical Reference Manual)
R is Net incoming radiation at the surface (MJ/m²/day or W/m²) which is equivilant to rsds - ?
G is Soil heat flux density (MJ/m²/day or W/m²)
\(ET_{0} = \frac{0.408 \Delta (R_n - G) + \gamma \frac{900}{T + 273} u_2 (e_s - e_a)}{\Delta + \gamma (1 + 0.34 u_2)}\)