Partitioning from interval average data¶
The flux partitioning procedure of [SS08] emphasizes the use of high-frequency eddy covariance data because it may be necessary to filter the data to satisfy variance similarity assumptions and obtain a physically consistent partitioning. However, once the filter has been applied (or if a filter is not required on a particular data set), the partitioning calculation is actually made using interval average values for Fq=<w’q’>, Fc=<w’c’>, var(q), var(c), corr(q,c), and WUE.
In fluxpart, the partitioning calculation using interval average values
is made in fluxpart.partition.fvspart_interval()
.
Example: Palatella et al. [PRV14] (Table 1) reported the following quantities for an hour time interval:
stddev(q) |
0.411163 g/m^3 |
stddev(c) |
5.182580 mg/m^3 |
<w’q’> |
0.033140 g/m^2/s |
<w’c’> |
-0.472108 mg/m^2/s |
corr(q, c) |
-0.881017 |
wue |
-37.158598 mg CO2 / g H2O |
A flux partitioning solution for this data can found with:
from fluxpart.partition import fvspart_interval
from fluxpart.containers import WQCData
# Note converting input to SI units
wue = -37.158598e-3
interval_data = WQCData(
var_q=0.411163e-3 ** 2,
var_c=5.182580e-6 ** 2,
wq=0.033140e-3,
wc=-0.472108e-6,
corr_qc=-0.881017,
)
massfluxes, fvsp = fvspart_interval(interval_data, wue, wipe_if_invalid=True)
print(fvsp)
print()
print(massfluxes)
which produces:
-------------
FVSP Solution
-------------
valid_partition: True
fvsp_mssg:
Wavelet filtering level: nan
var_q = 0.1691 (g/m^3)^2
var_c = 26.86 (mg/m^3)^2
corr_qc = -0.881
cov_w_q = 0.03314 g/m^2/s
cov_w_c = -0.4721 mg/m^2/s
corr_cp_cr = -0.7585
var_cp = 27.36 (mg/m^3)^2
sig_cr = 0.06352 mg/m^3
co2soln_id = 1
valid_root = True
root_mssg =
MassFluxes(
Fq = 0.03314 g/m^2/s,
Fqt = 0.01282 g/m^2/s,
Fqe = 0.02032 g/m^2/s,
Fc = -0.4721 mg/m^2/s,
Fcp = -0.4765 mg/m^2/s,
Fcr = 0.004389 mg/m^2/s)
The obtained results match closely those reported in [PRV14]:
fluxpart |
||
---|---|---|
var(cp) (mg/m^3)^2 |
27.358130 |
27.36 |
corr(cp,cr) |
-0.757626 |
-0.7585 |
<w’qt’> (g/m^3/s) |
0.012878 |
0.01282 |
<w’qe’> (g/m^3/s) |
0.020262 |
0.02032 |
<w’cp’> (mg/m^3/s) |
-0.476489 |
-0.4765 |
<w’cr’> (mg/m^3/s) |
0.004381 |
0.004389 |