Quality control
Libinsitu embeds several features for QC analysis :
Computes QC flags and embeds it into NetCDF files :
Via the CLI : command ins-transform
Via the Python API : function compute_qc_flags
Filters out flagged data :
Via the CLI : command ins-cat
Via Python API : parameter
skip_qc
of function netcdf_to_dataframe
NetCDF encoding
The QC flags are encoded into NetCDF following the CF convention. See the dedicated section in our convention
List of QC Flags
The following table shows the flags we currently process and embed into NetCDF files.
We provide the matching against the flags used in IEA-PVPS Task-16 (Anne Forstinger and Al, 2021)
This list of flags may evolve in next releases of libinsitu.
Test Category |
Reference |
Libinsitu Flag |
IEA-PVPS Flag |
Conditions |
Domain |
GHI |
DNI |
DIF |
---|---|---|---|---|---|---|---|---|
K-Tests |
Geuder Et Al. 2015; Gueymard 2017 |
T2C_seri_kn_kt |
FlagKnKt |
Kn < Kt |
(GHI > 50 W M2 And Kn > 0 And Kt >0) |
X |
X |
|
FlagKn |
Kn < (1100+0.03 ∗ ALT)/ETN) |
(GHI > 50 W M2 And Kn > 0) |
X |
X |
||||
FlagKt |
Kt < 1.35 |
(GHI > 50 W M2 And Kt > 0) |
X |
|||||
T2C_bsrn_kt |
FlagKlowSZA |
𝐾 < 1.05 |
(SZA < 75° And GHI > 50 W M2 And 𝐾 > 0 ) |
X |
X |
|||
FlagKhighSZA |
𝐾 < 1.1 |
(SZA ≥ 75° And GHI > 50 W/m2 And 𝐾 > 0) |
X |
X |
||||
T2C_seri_k_kt |
FlagKKt |
𝐾 < 0.96 |
(Kt > 0.6 And GHI > 150 W/m² And SZA < 85° And 𝐾 > 0) |
X |
X |
|||
|
Long And Dutton 2002 |
T3C_bsrn_3cmp |
Flag3lowSZA |
abs(GHI/(DNI⋅cos(SZA)+DIF) − 1) ≤ 0.08 |
(SZA ≤ 75° And GHI > 50 W/m2) |
X |
X |
X |
Flag3highSZA |
abs(GHI/(DNI⋅cos(SZA)+DIF) − 1) ≤ 0.15 |
(SZA > 75° And GHI > 50 W/m2) |
X |
X |
X |
|||
T1C_erl_GHI |
FlagERLGHI |
−2 ≤ GHI ≤ 1.2 ⋅ ETN ⋅ Cos(SZA)^1.2+50 |
All Data |
X |
||||
T1C_erl_DIF |
FlagERLDIF |
−2 ≤ DIF ≤ 0.75 ⋅ ETN ⋅ Cos(SZA)^1.2+30 |
All Data |
X |
||||
T1C_erl_DNI |
FlagERLDNI |
−2 ≤ DNI ≤ 0.95 ⋅ ETN ⋅ Cos(SZA)^0.2+10 |
All Data |
X |
||||
T1C_ppl_GHI |
FlagPPLGHI |
−4 ≤ GHI ≤ 1.5 ⋅ ETN ⋅ Cos(SZA)^1.2+100 |
All Data |
X |
||||
T1C_ppl_DIF |
FlagPPLDIF |
−4 ≤ DIF ≤ 0.95 ⋅ ETN ⋅ Cos(SZA)^1.2+50 |
All Data |
X |
||||
T1C_ppl_DNI |
FlagPPLDNI |
−4 ≤ DNI ≤ ETN |
All Data |
X |
||||
Tracker-Off Test |
Long And Shi 2008 |
Tracker_off |
FlagTracker |
DIF < 0.85*GHI |
(GHI > 50 W/m2 And GHI > 0.85 * (0.8*ETN*cos(SZA))) |
X |
X |