Unread postby cbay » Fri Dec 27, 2013 7:31 am
Here is some information i found useful for using WindNinja
When you first open WindNinja click Input. You will need to click "Dowload File" and create a file of your area. This will take you to a map where the USGS data is to be downloaded. You will select your area here and name it and save.
After that, you will click "Open File" in the future for that area and select your area every time you do a model.
Click "Surface Input". You can change the vegetation type (trees, grass,,). You will also need to select your time zone. This is necessary (especially for thermals).
Then select Diurnal Input and check the box "Use Diurnal Wind"
The Stability Input i'm not sure how much it matters; try it either way and decide for yourself.
Next click Wind Input. Check the box "Domain Average Wind" and down below you will see the wind speed input, direction, time, date....
Put in a wind speed. For me i find that i only get relevant data by using decimal numbers; 0.50, 0.40, 0.30, 0.20, and 0.15. Maybe you can use normal wind speeds and have better luck than i have. But i ended up using each of the above for a model and it represents the way i see the wind in my area. If you just want to do one outpt at a time, just do one row at a time. Easier for me anyway.
Enter a direction. This will be degrees; 360 north, 180 south, 220 sw, etc.
Enter a time. This is necessary for diurnal info and will change the thermals.
I leave the other inputs empty. You will likely see thermal change with changing the air temp as well.
Next click "Output" and select Google Earth and check the box "Create Google Earth Files"
Now click "Solve" and click "Solve" below
When simulations are finished click "close" and then click "Open Output Files Path". This will take you to the same file location that your area file is saved. You will see the .kmz file there and double click it and it will open Google Earth to your wind model.
You will find as you try different models they will add up in the folder and it gets hard to tell which one is which. So immediately i rename each one to better identify them. Examples (southwest at .50 at 2o'clock), (north at .20 at 2), etc...
Again, the wind speed input i find did not correspond to what i see nor did it show a thermal or topography flow change until i started to use input numbers from .50 down to .15. With an input as low as .25 i find nearly a total thermal. Very interesting to note the thermals at with low wind input. As i work up to .50 i can get a representation of the thermals working down towards the bottom of the hills.
Another important thing is to uncheck each model on Google Earth in "My Places" after every run model. Otherwise when you run another model it will overlay every one of on top of each other. Very important.
Well the tutorial does a much better job of explaining things, but the wind speed input and unchecking the previous models in Google Earth (My Places) made things actually work and were not discussed in the tutorial.
If you get a collection of models for different scenarios and want to go to them, you will find (or at least in my case), that i had to run another model to get to the saved ones. So you may want to copy / paste your saved models into another folder in "My Documents". I found that worked so i can quickly go to one and run it without making another one.
If Dan has marked spots he thinks bucks are likely to bed with a certain wind on maps for you, you may find as i have that he has absolutely nailed the locations as far as the wind models are concerned. They are the locations that have the most arrows pointing from the most locations. You can also tell a little about the thermal tunnel by noting the lower wind speeds (blue); where the slope /diurnal and the general wind meet. Of course this changes with the general wind speed that you enter into the model. One thing i did to "calibrate" the model was to enter wind speeds until it corresponded to what i have seen at different locations in terms of thermal tunnel elevations.
There are going to be lots of shortcomings with any model like this, so take it with a grain of salt!!
Hope this helps,
Chris
