wiki.met.no kvalobs:kvoss:system:qc2:requirements:algorithms

Akima algorithm

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

Akima algorithm You are given a single independent variable x. The approach uses a cubic fit between the data points, so the slope is required at each data point in addition to the value of the point itself. The interpolating polynomial is written between the ith and i + 1st data points as:

Dip test - QC2d-1 - Revision 01

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

Dip test - QC2d-1 - Revision 02

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

Dip test - QC2d-1 - Revision 02 CRITERIA: (1) |A(t)-A(t-2)| < |A(t-1) - A(t-2)| (2) |A(t)-A(t-1)| > δ (3) fs=2 for A(t-1) (4) fs=1 for A(t-2) where DELTA is dependent on the parameter The above was tried out with mixed success ... therefore rolled back to also requiring fs=2 for A(t) pending further specification

QC2d-1: Dip test

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

QC2d-1: Dip test * fs=2 for A(t), * fs=2 for A(t-1) * fs=1 for A(t-2) A dip is detected if and where is specified in the algorithm configuration. then receives a corrected value by interpolation. The neighboring points at t-2 and t may not have missing original values and have to match the flags specified in

Dip test - QC2d-1

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

Dip test - QC2d-1 The Kvalobs approach The flag fs=2 is detected on the observation A(t2), the previous value A(t1) is also flagged fs=2, and the next previous value A(t0) is flagged fs=1. If | A(t2) - A(t0) | < | A(t1) - A(t0) | then set fs=9 on A(t1) set fs=4 on A(t2)

GAP INTERPOLATION

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

Feedback on this page (LA): * The size of gap is essential for allowing interpolation. * The second derivative of the curve (f“(x)) the last 2-3 hours before the gap should influence on the size of an acceptable gap for interpolation; and also influence on whether to interpolate the first two hours of a larger gap or not. E.g.: If f

Temporal interpolation for "one-point" gaps in hourly temperature

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

Temporal interpolation for "one-point" gaps in hourly temperature Description of Method * Locate a single missing value * Check if data available immediately before and after the interval * If available generates first estimate from linear interpolation

QC2h-1: Plumatic Controls

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

QC2h-1: Plumatic Controls * [Specification] * QC2h1 spesifikasjon See also the Plumatic documentation in the source code repository. Procedure The algorithm first checks prioritet 2, 3, and 4 from the specification and applies the correpsonding flag modifications. After that, the sliding aggregation check is performed, excluding any periods with data matching

Statistics control Quantile method

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

Statistics control Quantile method Description of Method The distribution of all observations within one month timespan is represented by the quartiles Q1, Q2 and Q3. The station and month specific reference quartiles Q1', Q2' and Q3' is calculated from the climate database either by the previous ten years or from a regional reference station.

QC2d-4 Statistics control Mean Value Method

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

QC2d-4 Statistics control Mean Value Method Description of Method The arithmetic mean value of 30 days observations M is calculated. Day d is the date 15 days prior to present. Daily station specific normal values is extracted from the climate database. The value M' is the normal value of day d.

QC2d-4 Statistics control Accumulation Method

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

QC2d-4 Statistics control Accumulation Method Description of Method The monthly accumulated precipitation RRM is calculated. The corresponding normal monthly accumulated precipitation RRM' is retrieved form the climate data base. Corresponding accumulated value at three neighbour stations are RRMn1, RRMn2, RRMn3. Corresponding reference accumulated value at three neighbour stations are RRMn'1, RRMn'2, RRMn'3.

QC2h1 – tidsseriekontroll av pluviometermålinger i ettertid

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

QC2h1 – tidsseriekontroll av pluviometermålinger i ettertid Versjon 0.9 17.mars 2011 Per-Ove Kjensli Versjon 1.0 30.november 2011 Karianne Ødemark RR_01 - minuttdata av nedbør, oppløsning 0.1 (eller 0.2 millimeter). Opplysning om oppløsning er instrumentspesifikke metadata, og de må gjøres tilgjengelig for kontrollen – og må implementeres.

Redistribution of 24 hour precipitation

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

Redistribution of 24 hour precipitation RR_24 is the precipitation collected over the last 24 hours. The Qc1 check precipcollected_flag identifies if an RR_24 value is valid (fd=1), erroneous (fd=3) or is the accumulation (fd=2) of a number (N) of consecutive 24 hour periods, where N>1. For the case fd=2, the accumulated value shall be distributed over the N 24 hours periods.

QC2d-2: SingleLinear

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

QC2d-2: SingleLinear Replaces a single missing value with a value obtained by linear interpolation between the immediate neighbors. See the specification [3.2]. The neighboring values may not be missing and must match the neighbor_*flags specification. If an interpolation is made, cfailed receives a message

Descriptive Title of Algorithm

anonymous@undisclosed.example.com (Anonymous) — Tue, 31 May 2022 09:29:32 +0000

Descriptive Title of Algorithm Description of Method ... Quality Control Level * ... Run Parameters It shall be possible to run the algorithm for * ... * ... * ... Characteristics of the data to which the method is applied CONTROLINFO AND/OR USEINFO