Quality control

Libinsitu embeds several features for QC analysis :

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

BSRN’s Closure

BSRN’s Extremely Rare Limits

BSRN’s Physically Possible Limits

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