As in past projects, going back to CASES99 and most recently at CFACT, I split the vertical profile into a short tower and a tall tower, to avoid the influence of the tall tower's superstructure on the airflow sensed by the lower sensors. For M2HATS, I placed the short tower near the horizontal array to reduce the number of CSATs by one, with 4m.t0 doing double duty for the vertical and horizontal array. However, due to the airport glide slope restrictions, tt ended up almost a mile away. Due to the overall homogeneity of the site and the length of the fetch for the tt sensors, I thought that this separation would be acceptable.
However, after walking around, Jielun commented on the differences in vegetation height at these two locations and Chenning commented today about the difference in terrain height (and maybe slope) at these two locations. The profile webplots that I just got going today confirm their suspicions: there are definite jumps in the combined wind speed and temperature profiles.
Chenning suggests that we add a short profile tower near tt to create mean velocity profile at the same location. His suggestion was to use our 2-D sonics (wind observers) for this – I'll assume at 1, 2, 3, 4m. This would require:
- Another 15' tower. I assume (though I didn't look) that we have at least a 10' and 5' section left over. I don't know if we have a spare base plate. I assume that we have enough ratchet straps and stakes for another set.
- A box of (4) wind observers would have to be shipped from Boulder
- We should have enough extra booms. The wind observers have compatible cassettes (though we've never put them in a vertical profile before, surprisingly). We have 2 spare tower clamps, I think. We could probably improvise another 2, or have two more (the last 2 new, or 2 very old style) also sent from Boulder.
- We could create another DSM from a spare or just plug these sensors into unused ports on ttt – we should have enough long serial cables (4x35m?) for this.
- The extra power draw on tt shouldn't be too large.
- All of this begs the question of whether we should also add corresponding TRHs. We have 4 SHTs, I haven't looked but assume we have 4 spare housings. We have 4 spare TRH booms. I don't know how many extra cell clamps we have – there are a few.
I'd appreciate comments from anybody about this project addition!