...
| Date/Time | Location | Tare (g) | Wet (g) | Dry (g) | Density (g/cm^3) | Qsoil (cm^3/cm^3) % | EC5 Reading (cm^3/cm^3) % | Diff (cm^3/cm^3) % |
|---|---|---|---|---|---|---|---|---|
| 20 Feb 2015/1157 | bao, 2--5cm | 5.58 | 100.74 | 83.54 | 1.17 | 25.89 | 23.98 | -1.9 |
| 20 Feb 2015/1112 | bao, 10--13cm | 2.15 | 99.59 | 87.36 | 1.28 | 18.41 | 16.38 | -2.0 |
| 20 Feb 2015/1129 | bao, 20-23cm | 2.50 | 89.51 | 78.51 | 1.14 | 16.56 | 13.17 | -3.4 |
| 9 Mar 2015/1430 | ehs, 2--5cm | 16.477 | 142.333 | 127.741 | 1.67 | 21.96 | 28.4 | 6.4 |
| 20 Apr 2015/1500 | ehs,4--7cm | 8.237+8.260 | 81.960+60.946 | 70.854+52.124 | 1.60 | 30.00 | 29.47 | -0.5 |
| 20 Apr 2015/1500 | ehs, 9--12cm | 8.232+8.214 | 71.380+74.505 | 62.335+65.162 | 1.67 | 27.68 | 28.20 | 0.5 |
| 20 Apr 2015/1500 | ehs, 19–22cm (not completely full, by about 2mm?) | 8.265+2.139 | 96.082+29.133 | 84.192+25.476 | 1.49 (likely low) | 23.40 | 26.00 | 2.6 |
22 May 2015/1400 | bao, 3-6 | 2.126+2.379 | 56.184+61.353 | 46.364+50.476 | 30.1 | |||
| 22 May 2015/1400 | bao, 8-11 | 2.111+2.094 | 70.604+60.122 | 58.938+49.878 | 32.0 | |||
| 22 May 2015/1400 | bao, 18-21 | 2.079+2.107 | 60.887+70.702 | 50.456+58.281 | 29.4 |
Note: Dry taken 23 Feb after air-drying in the lab for 3 days, then baking in the toaster oven for an hour. (The oven got rid of about another 1.5g in each sample.)
...
tare = c(5.58, 2.15, 2.50, 16.477, 8.237+8.260, 8.232+8.214, 8.265+2.139, 2.126+2.379, 2.111+2.094, 2.079+2.107)
wet = c(100.74, 99.59, 89.51, 142.333, 81.960+60.946, 71.380+74.505, 96.082+29.133, 56.184+61.353, 70.604+60.122, 60.887+70.702)-tare
dry = c(83.54, 87.36, 78.51, 127.741, 70.854+52.124, 62.335+65.162, 84.192+25.476, 46.364+50.476, 58.938+49.878, 50.456+58.281)-tare
vol = 3*pi*(5.31/2)^2
...
ec5 = c(23.98, 16.38, 13.17, 28.4, 29.47, 28.20, 26.00), 30.1, 32.0, 29.4)
ch = as.character(c(1,2,3,1,1,2,3,1,2,3))
col = c(1,1,1,2,2,2,2,1,1,1)
par(las=1,tck=0.02,xaxs="i",yaxs="i")
plot(moist,ec5,xlim=c(0,40),ylim=c(0,40),col=col,pch=ch); abline(0,1,lty=2)
bias = c(1.5,1.5,4.0,0.5,0.5,-0.5,-2.5,1.5,1.5,4.0)
plotmatplot(moist,ec5+bias,xlim=c(0,40),ylim=c(0,40),col=col,pch=ch,xlab="Gravimetric (%Vol)",ylab="EC5, bias adjusted (%Vol)"); abline(0,1,lty=2)
legend(2,38,c("bao.20cm","bao.10cm","bao.5cm","ehs.20cm","ehs.10cm","ehs.5cm"),col=c(1,1,1,2,2,2),pch=c("3","2","1","3","2","1"))
title("CABL Gravimetric Sampling")
As of 5/26/15, I would set biases (add to ec5 to make correct) to be:
bao.5cm: 1.5%
bao.10cm: 1.5%
bao.20cm: 4%
ehs.5cm: 0.5%
ehs.10cm: -0.5%
ehs.20cm: -2.5%
5/29/15:
I've also tried to remove the diurnal cycle, assuming that it is a temperature affect (since vegetation shouldn't have been very active, especially at the beginning of this experiment). I use the correction:
Q_correct(z) = Q_meas(z) - xm*Tsoil(z),
where:
xm = c(0.11,0.18,0.17,0.12,0.20,0.18) for bao 5,10,20 and ehs 5,10,20 cm, respectively.
With this temperature correction, the bias correction changes a bit:
Q_correct(z) = Q_meas(z) + xb - xm*Tsoil(z)
xb = c(2.3,2.7,5.0,0.5,-0.5,-2.5) (same order as xm, above)
After these corrections, I get the attached plot: Qgrav.pdf, where the left panels are from bao, the right panels from ehs, the top panels are just a bias correction and the bottom panels are with the combined correction. Also on these plots are the gravimetric samples as circles. For ehs, Qsoil was read manually (independent of the data system) at the time of the second soil cores, and these values are plotted as "+" (though I don't have the corresponding Tsoil to apply the combined correction).