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Dateproduced inDate: 09/06/2021

Ref: C3S_D312b_Lot1.2.2.3-v2.1_202010_PQAR_ECVSurfaceRadiationBudget_v1.0

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title	Table of Contents

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History of modifications

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Version	Date	Description of modification	Chapters / Sections
V1.0	28/02/2019	First version	All
V1.1	28/02/2019	Full description of the net fluxes algorithms	All
V2.0	01/02/2021	Merged version for all CLARA Product Family	All
V2.1	19/05/2021	Update on Surface Radiation ICDR 2.x	Chapters 1,2,5

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Reference ID	Document
D1	Validation Report, CM SAF Cloud, Albedo, Radiation dataset, AVHRR-based, Edition 2.1 (CLARA-A2.1), Surface Radiation Products, Issue 2.4 Link to CM SAF Validation Report
D2	CM SAF Product Requirement Document, Issue 3.7 Link to CM SAF PRD
D3	Data Set Description CM SAF CLARA A1 surface radiation, Issue 1.0 Link to CM SAF DSD document
D4	Bobryshev, O. (2021) C3S Surface Radiation Budget Service: Product User Guide and Specification, Surface Radiation Budget Link to C3S PUGS document . Copernicus Climate Change Service, Document ref. C3S_D312b_Lot1.3.5.1-v2.1_202007_PUGS_ECVSurfacRadiationBudget_v1.0 SRB CLARA Product Family: Product User Guide and Specification (PUGS) Last accessed on 01.09.2023
D5	Product User Manual CM SAF Cloud, Albedo, Radiation data record, AVHRR-based, Edition 2.1 (CLARA-A2.1), Surface Radiation	D5	Product User Manual CM SAF Cloud, Albedo, Radiation data record, AVHRR-based, Edition 2.1 (CLARA-A2.1), Surface Radiation Products, Issue 2.3 Link to CM SAF PUM document
D6	Validation Report CM SAF Cloud, Albedo, Radiation data record, AVHRR-based, Edition 2 (CLARA-A2), Surface Albedo, Issue 2.4 Link to CM SAF Validation Report (surface albedo)
D7	[GCOS- 200] Global Climate Observing System, Implementation Plan, 2016. World Meteorological Organization, Geneva, Switzerland. https://library.wmo.int/doc_num.php?explnum_id=34
D8	Validation Report ICDR AVHRR, based on CLARA-A2 methods, Surface Radiation Products, Issue 2.1 Link to CM SAF Validation Report ICDR

Acronyms

D9	Meirink, J.F., et al, (2023) C3S cross ECV document Service: Key Performance Indicators (KPIs).

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Acronym	Definition
AVHRR	Advanced Very High Resolution Radiometer
BSRN	Baseline Surface Radiation Network
C3S	Copernicus Climate Change Service
CDR	Climate Data Record
CLARA-A2.1	CLARA-A2: CM SAF CLoud, Albedo and Radiation data record – AVHRR based, Edition 2.1
CM SAF	Satellite Application Facility on Climate Monitoring
DWD	Deutscher Wetterdienst (German Meteorological Service)
ECV	Essential Climate Variable
EUMETSAT	European Organization for the Exploitation of Meteorological Satellites
MetOp	Meteorological Operational Satellite
NOAA	National Oceanic and Atmospheric Administration
PUM	Product User Manual
SAL	Surface Albedo
SDL	Surface Downwelling Longwave radiation
SIS	Surface Incoming Shortwave Radiation
SNL	Surface Net Longwave radiation
SNS	Surface Net Shortwave radiation
SOL	Surface Outgoing Longwave radiation
SRB	Surface Radiation Budget
SRS	Surface Reflected Shortwave radiation

General definitions

In the scope of the Copernicus Climate Change Service (C3S), two Surface Radiation Budget datasets are combined into one Climate Data Record (CDR) called "CLARA product family".

The first dataset, EUMETSAT's CM SAF CLARA-A2.1, is the core of this CDR. The second dataset includes extra data products that are not included in the CLARA-A2.1 dataset. The core data products are brokered from CM SAF. The extra net fluxes are not included in the brokered CLARA-A2.1 dataset and are calculated specifically within the C3S project as complimentary data for the convenience of users. Their format is as close as possible to the CLARA-A2.1 and the datasets are meant to be used together. Both datasets are frequently updated with Interim Climate Data Records (ICDRs) or simply extensions, generated using the same software and algorithms to cover more recent periods. The ICDR part for all products covers period from 2019 to 2020.

This separation into two datasets is necessary to keep the origin of the data, e.g. licence affiliations: "EUMETSAT's CM SAF" and "C3S", clear for individual products (Table 1)

Table 1: Licence overview of the CLARA product family Surface Radiation Products available through the CDS

Year

CDR Type

...

CLARA Product Family

...

SIS

...

SDL, SOL

...

SRS

...

Net Fluxes

...

Longwave fluxes

...

Extra data products

...

1982 – 2018

...

TCDR

...

CM SAF (CLARA-A2.1)

...

CM SAF

(CLARA-A2.1)

...

C3S

...

C3S

...

2019 – 2020

...

ICDR

...

CM SAF

(CLARA-A2.1 ICDR)

...

C3S

...

C3S

...

C3S

The longwave fluxes are not included in the CM SAF ICDR plans for the current phase. To ensure the dataset integrity and continuity, they are calculated within the C3S for the ICDR part. As such, the longwave fluxes change their licence affiliation, namely they are provided within the C3S project for the ICDR part (2019-2020) and are brokered from EUMETSAT’s CM SAF for the TCDR part (1982 to 2018).

Furthermore the CM SAF CLARA-A2.1 dataset has a temporal coverage of January 1982 to June 2019 (as described in [D2]), but TCDR data are only being brokered to the CDS up to December 2018. Data available from the CDS for January 2019 to December 2020 are brokered/derived from the CLARA A2.1 ICDR¹.

In contrast to the original CM SAF CLARA-A2.1 dataset, the brokered service within Copernicus solely provides:

Level-3 data – excluding the level-2b data format.
Data on a global equal angle grid – excluding the polar grid format.
An aggregated version of all satellite data – excluding the provision of the individual satellite datasets.

...

icon	false

...

,

Document ref. C3S2_D312a_Lot1.3.7.1_202303_Unified_KPI_Approach_v1.0

Key Performance Indicators (KPIs)

Last accessed: 23.08.2023

D10

Bobryshev, O., Mikalsen, A.C. (2021) C3S Surface Radiation Budget

Service: Product Quality Assurance Document. Copernicus Climate Change Service,

Document ref. C3S_D312b_Lot1.2.2.2-v2.1_202007_PQAD_ECVSurfaceRadiationBudget_v1.0

SRB CLARA Product Family: Product Quality Assurance Document (PQAD)

Last accessed on 01.09.2023

Acronyms

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title	Click here to expand the list of acronyms

Acronym	Definition
AVHRR	Advanced Very High Resolution Radiometer
BSRN	Baseline Surface Radiation Network
C3S	Copernicus Climate Change Service
CDR	Climate Data Record
CLARA-A2.1	CLARA-A2: CM SAF CLoud, Albedo and Radiation data record – AVHRR based, Edition 2.1
CM SAF	Satellite Application Facility on Climate Monitoring
DWD	Deutscher Wetterdienst (German Meteorological Service)
ECV	Essential Climate Variable
EUMETSAT	European Organization for the Exploitation of Meteorological Satellites
MetOp	Meteorological Operational Satellite
NOAA	National Oceanic and Atmospheric Administration
PUM	Product User Manual
SAL	Surface Albedo
SDL	Surface Downwelling Longwave radiation
SIS	Surface Incoming Shortwave Radiation
SNL	Surface Net Longwave radiation
SNS	Surface Net Shortwave radiation
SOL	Surface Outgoing Longwave radiation
SRB	Surface Radiation Budget
SRS	Surface Reflected Shortwave radiation

List of Figures

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title	Click here to expand the list of tables

Figure 1-1: Spatial distribution of the propagated SRS accuracies for 1982-2018 (left) and 2019-2020 (right) years

Figure 1-2: Spatial distribution of the propagated SNS accuracies for 1982-2018 (left) and 2019-2020 (right) years

List of Tables

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title	Click here to expand the list of figures

Table 2-1: Summary of validation results for SDL and SOL ICDR datasets (2019-2020)

Table 3-1: Summary of KPI results with 2.5 and 97.5 percentiles and number of ICDR months within the range

Table 4-1: Summary of the requirements and achieved accuracies of the brokered CLARA-A2.1 data products], Section 1 [D1 for SIS, SOL, SDL TCDR, D8 for SIS ICDR]

General definitions

In the scope of the Copernicus Climate Change Service (C3S), two Surface Radiation Budget datasets are combined into one Climate Data Record (CDR) called "CLARA product family".

The first dataset, EUMETSAT's CM SAF CLARA-A2.1, is the core of this CDR. The second dataset includes extra data products that are not included in the CLARA-A2.1 dataset. The core data products are brokered from CM SAF. The extra net fluxes are not included in the brokered CLARA-A2.1 dataset and are calculated specifically within the C3S project as complimentary data for the convenience of users. Their format is as close as possible to the CLARA-A2.1 and the datasets are meant to be used together. Both datasets are frequently updated with Interim Climate Data Records (ICDRs) or simply extensions, generated using the same software and algorithms to cover more recent periods. The ICDR part for all products covers period from 2019 to 2020.

This separation into two datasets is necessary to keep the origin of the data, e.g. licence affiliations: "EUMETSAT's CM SAF" and "C3S", clear for individual products (Table 1)

Table 1: Licence overview of the CLARA product family Surface Radiation Products available through the CDS

Year	CDR Type	CLARA Product Family
		SIS	SDL, SOL	SRS	Net Fluxes
			Longwave fluxes	Extra data products
1982 – 2018	TCDR	CM SAF (CLARA-A2.1)	CM SAF (CLARA-A2.1)	C3S	C3S
2019 – 2020	ICDR	CM SAF (CLARA-A2.1 ICDR)	C3S	C3S	C3S

The longwave fluxes are not included in the CM SAF ICDR plans for the current phase. To ensure the dataset integrity and continuity, they are calculated within the C3S for the ICDR part. As such, the longwave fluxes change their licence affiliation, namely they are provided within the C3S project for the ICDR part (2019-2020) and are brokered from EUMETSAT’s CM SAF for the TCDR part (1982 to 2018).

Furthermore the CM SAF CLARA-A2.1 dataset has a temporal coverage of January 1982 to June 2019 (as described in [D2]), but TCDR data are only being brokered to the CDS up to December 2018. Data available from the CDS for January 2019 to December 2020 are brokered/derived from the CLARA A2.1 ICDR¹.

In contrast to the original CM SAF CLARA-A2.1 dataset, the brokered service within Copernicus solely provides:

Level-3 data – excluding the level-2b data format.
Data on a global equal angle grid – excluding the polar grid format.
An aggregated version of all satellite data – excluding the provision of the individual satellite datasets.

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	note1
	note1

1 The CM SAF CLARA-A2.1 and CLARA-A2.1 ICDR have a 6 month overlap from 2019/01 to 2019/06. One of the input datasets used in CLARA-A2.1, namely ERA-interim reanalysis data, is only available until August 2019 and dates beyond that are only covered by the newer ECMWF reanalysis version (ERA-5) and ECMWF IFS model. The CLARA-A2.1 ICDR uses ERA data from January 2019 onwards. The 6-month overlap between CLARA-A2.1 and CLARA-A2.1 ICDR is needed to ensure a sufficient period for data comparison and validation. CM SAF ATBD-ICDR contains more information on the overlap period.

Scope of the document

This document is the Product Quality Assessment Report (PQAR) for CLARA Product family CDR. This document provides validation results for the Climate Data Record (CDR) of the Surface Radiation Budget.

Executive summary

The brokering service of the CLARA-A2.1 data products includes 37 years (1982-2018) of level-3 data (monthly means) on a regular global latitude-longitude grid (with 0.25° x 0.25° resolution), merged from various polar orbiting satellites. It includes three products: the Surface Incoming Shortwave radiation (SIS), the Surface Outgoing Longwave radiation (SOL), and the Surface Downwelling Longwave radiation (SDL). SIS daily averages are also available within C3S. This CDR is brokered from EUMETSAT’s CM SAF. Therefore, this document refers to the original EUMETSAT CM SAF Validation Report [D1, D8]. It describes the validation methodology and the validation results.

The extra data products (produced specifically within the C3S project) are: the Surface Reflected Shortwave radiation (SRS), the Surface Net Shortwave radiation (SNS), the Surface Net Longwave radiation (SNL), and the Surface Radiation Budget (SRB). Validation results for these extra data products are described within this document.

The CLARA based ICDR data record is a continuation of the products of the CLARA-A2.1 and the extra data products. It extends both products by 2 years (2019-2020). The longwave fluxes are not included in the CM SAF ICDR plans for the current phase. Therefore SOL and SDL change their license affiliation, namely they are provided within the C3S project for the ICDR part (2019-2020) and are brokered from EUMETSAT’s CM SAF for the TCDR part (1982 to 2018). Table 1 provides an overview of the licenses for all data CLARA family products. Validation results for SDL and SOL ICDR data products are described within this document.

An executive summary of the evaluation of the CLARA-A2.1 and CLARA-based ICDR surface radiation dataset can be found in CM SAF Validation Report, Section 1 [D1, D8]

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	table2
	table2

Table 2: Summary of the accuracy of the brokered CLARA-A2.1 data products, [D1] Section 1 for SIS, SOL, SDL TCDR, [D8] Section 1 for SIS ICDR. The accuracy estimation of SOL and SDL ICDR extensions is performed within the C3S using the algorithms developed by CM SAF

Product Name	Dataset accuracy [W/m²]
Product Name	TCDR	ICDR
SIS monthly means	9.5	9.6
SIS daily means	18.6	22.9
SDL	8.1	15.8
SOL	13.8	9.2

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	table3
	table3

Table 3: Summary of the accuracy of the extra data products

Product Name	Propagated accuracy [W/m²]
Product Name	TCDR	ICDR
SRS	7.8	6.5
SNS	13.0	14.2
SNL	21.9	25.0
SRB	34.9	39.2

1. Product validation methodology

In the scope of the Copernicus Climate Change Service (C3S), two Surface Radiation Budget datasets are combined into one Climate Data Record (CDR) called the "CLARA product family".

1.1 Validation methodology for SIS, SOL, SDL

CLARA-A2.1 data products include the Surface Incoming Shortwave radiation (SIS), the Surface Outgoing Longwave radiation (SOL), and the Surface Downwelling Longwave radiation (SDL) datasets. These datasets were validated against reference data records from surface measurements obtained by the Baseline Surface Radiation Network (BSRN, Ohmura et al., 1998, Driemel et al., 2018). The reference dataset is described in detail in CM SAF Validation Report [D1], Section 4.

Therefore, this document refers to the original EUMETSAT CM SAF Validation Report [D1, D8]. It describes the validation methodology and the validation results. The accuracy estimation of SOL and SDL ICDR extensions is performed within the C3S using the algorithms developed by CM SAF

The validation of the SIS ICDR (2019-2020) product is described in CM SAF Validation Report ICDR, Sections 5.2 [D8]. The validation methodology of SOL and SDL ICDR extensions is performed within the C3S using the algorithms developed by CM SAF.

The validation methodology and definitions of the main metrics are provided in the C3S Product Quality Assurance Document (PQAD) [D4], Section 3, which refers to CM SAF Validation Report [D1], Section 5 and 5.1.

1.2 Validation methodology for CLARA family extra data products

The performed validation approach for extra data products is based on the method of error propagation. These data products are the Surface Reflected Shortwave radiation (SRS), the Surface Net Shortwave radiation (SNS), the Surface Net Longwave radiation (SNL), and the Surface Radiation Budget (SRB).

The ICDR part data are validated in the same way as the TCDR

1.2.1 Surface Reflected Shortwave Radiation (SRS)

The accuracy of the SRS is determined based on the accuracy of the Surface Incoming Shortwave Radiation (SIS) from the Surface Radiation Budget brokered from EUMETSAT’s CM SAF CLARA-A2.1 dataset [D1], and the Surface Albedo (SAL), not provided within the C3S.

The accuracy for the SRS is calculated using the fixed accuracy values for the SIS ( ΔSIS = 10 W/m²) and the relative error of the SAL ( ΔSAL = 25% of the SAL value). These values are the target requirements for accuracy from CM SAF Product Requirement Document [D2]. Resulting global mean accuracy for the SRS is 7.8 W/m² for TCDR and 6.5 W/m²for ICDR. Figures 1-1 and 1-2 provide the spatial distribution of the propagated SNS accuracies.

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	figure1_1
	figure1_1

Figure 1-1: Spatial distribution of the propagated SRS accuracies for 1982-2018 (left) and 2019-2020 (right) years

1.2.2 Surface Net Shortwave Radiation (SNS)

The accuracy of the SNS is determined based on the accuracy of the SIS and the SAL datasets.

Estimations of the accuracy of the SIS product is given in CM SAF Validation Report [D1] and the accuracy of the SAL product is given in CM SAF Validation Report, Surface Albedo [D6].

The accuracy for the SRS is calculated using the fixed accuracy values for the SIS ( ΔSIS = 10 W/m² ) and the relative error of the SAL ( ΔSAL = 25% of the SAL value). These values are the target requirements for accuracy from CM SAF Product Requirement Document [D2]. Resulting global mean accuracy for the SNS is 13.0 W/m². Figure 1-2 provides the spatial distribution of the propagated SNS accuracies.

Image Added

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	figure1_2
	figure1_2

Figure 1-2: Spatial distribution of the propagated SNS accuracies for 1982-2018 (left) and 2019-2020 (right) years

1.2.3 Surface Net Longwave Radiation (SNL)

The accuracy of the SNL is defined by the accuracy of the Surface Downwelling Longwave Radiation (SDL) and the Surface Outgoing Longwave Radiation (SOL), both datasets are the Surface Radiation Budget brokered from EUMETSAT’s CM SAF CLARA-A2.1 [D1].

Estimations of the accuracy of the SDL and the SOL products are given in CM SAF Validation Report [D1].

The accuracy for the SNL is calculated using the fixed accuracy values for the SDL ( ΔSDL = 8.13 W/m² ) and the SOL ( ΔSOL = 13.77 W/m² ). Resulting global mean accuracy for the SNL is 21.9 W/m².

Global mean accuracy for the SNL ICDR is 25.0 W/m².

1.2.4 Surface Radiation Budget (SRB)

The accuracy of the SRB is defined by the accuracy of the SNS and the SNL datasets.

The accuracy for the SRB is calculated using the fixed accuracy values for the SNS ( ΔSNS = 13.0 W/m² ) and the SNL ( ΔSNL = 21.9 W/m² ).

Resulting global mean accuracy for the SRB is 34.9 W/m².

Global mean accuracy for the SNL ICDR is 39.2 W/m².

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validation
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2. Validation results

2.1 Validation results for SIS, SOL, SDL

The TCDR (1982-2018) validation results are fully described in CM SAF Validation Report [D1], Section 5. The validation results for the SIS are provided in CM SAF Validation Report [D1], Section 5.2 and 5.2. The validation results for the SOL are provided in CM SAF Validation Report [D1], Section 5.3. The validation results for the SDL are provided in CM SAF Validation Report [D1], Section 5.4. Considerations for climate applications are provided in CM SAF Data Set Description [D3], Section 6. Conclusions for the validation results are provided

Scope of the document

This document is the Product Quality Assessment Report (PQAR) for CLARA Product family CDR. This document provides validation results for the Climate Data Record (CDR) of the Surface Radiation Budget.

Executive summary

The brokering service of the CLARA-A2.1 data products includes 37 years (1982-2018) of level-3 data (monthly means) on a regular global latitude-longitude grid (with 0.25° x 0.25° resolution), merged from various polar orbiting satellites. It includes three products: the Surface Incoming Shortwave radiation (SIS), the Surface Outgoing Longwave radiation (SOL), and the Surface Downwelling Longwave radiation (SDL). SIS daily averages are also available within C3S. This CDR is brokered from EUMETSAT’s CM SAF. Therefore, this document refers to the original EUMETSAT CM SAF Validation Report [D1, D8]. It describes the validation methodology and the validation results.

The extra data products (produced specifically within the C3S project) are: the Surface Reflected Shortwave radiation (SRS), the Surface Net Shortwave radiation (SNS), the Surface Net Longwave radiation (SNL), and the Surface Radiation Budget (SRB). Validation results for these extra data products are described within this document.

The CLARA based ICDR data record is a continuation of the products of the CLARA-A2.1 and the extra data products. It extends both products by 2 years (2019-2020). The longwave fluxes are not included in the CM SAF ICDR plans for the current phase. Therefore SOL and SDL change their license affiliation, namely they are provided within the C3S project for the ICDR part (2019-2020) and are brokered from EUMETSAT’s CM SAF for the TCDR part (1982 to 2018). Table 1 provides an overview of the licenses for all data CLARA family products. Validation results for SDL and SOL ICDR data products are described within this document.

An executive summary of the evaluation of the CLARA-A2.1 and CLARA-based ICDR surface radiation dataset can be found in CM SAF Validation Report, Section 1 [D1, D8]

Table 2: Summary of the accuracy of the brokered CLARA-A2.1 data products, [D1] Section 1 for SIS, SOL, SDL TCDR, [D8] Section 1 for SIS ICDR. The accuracy estimation of SOL and SDL ICDR extensions is performed within the C3S using the algorithms developed by CM SAF

...

Product Name

...

Dataset accuracy [W/m²]

...

TCDR

...

ICDR

...

SIS monthly means

...

9.5

...

9.6

...

SIS daily means

...

18.6

...

22.9

...

SDL

...

8.1

...

15.8

...

SOL

...

13.8

...

9.2

Table 3: Summary of the accuracy of the extra data products

...

Product Name

...

Propagated accuracy [W/m²]

...

TCDR

...

ICDR

...

SRS

...

7.8

...

6.5

...

SNS

...

13.0

...

14.2

...

SNL

...

21.9

...

25.0

...

SRB

...

34.9

...

39.2

1. Product validation methodology

In the scope of the Copernicus Climate Change Service (C3S), two Surface Radiation Budget datasets are combined into one Climate Data Record (CDR) called the "CLARA product family".

1.1 Validation methodology for SIS, SOL, SDL

CLARA-A2.1 data products include the Surface Incoming Shortwave radiation (SIS), the Surface Outgoing Longwave radiation (SOL), and the Surface Downwelling Longwave radiation (SDL) datasets. These datasets were validated against reference data records from surface measurements obtained by the Baseline Surface Radiation Network (BSRN, Ohmura et al., 1998, Driemel et al., 2018). The reference dataset is described in detail in CM SAF Validation Report [D1], Section 46.

Therefore, this document refers to the original EUMETSAT CM SAF Validation Report [D1, D8]. It describes the validation methodology and the validation results. The accuracy estimation of SOL and SDL ICDR extensions is performed within the C3S using the algorithms developed by CM SAF

Results are summarised in Table 1 in the Executive Summary.

The validation results for SIS ICDR monthly and daily are fully The validation of the SIS ICDR (2019-2020) product is described in CM SAF Validation Report ICDR [D8], Sections Section 5.2 [D8].

The validation methodology results of SOL and SDL ICDR extensions is performed within the C3S using the algorithms developed by CM SAF. The validation methodology and definitions of the main metrics are provided in the C3S Product Quality Assurance Document (PQAD) [D4], Section 3, which refers to CM SAF Validation Report [D1], Section 5 and 5.1.

1.2 Validation methodology for CLARA family extra data products

The performed validation approach for extra data products is based on the method of error propagation. These data products are the Surface Reflected Shortwave radiation (SRS), the Surface Net Shortwave radiation (SNS), the Surface Net Longwave radiation (SNL), and the Surface Radiation Budget (SRB).

The ICDR part data are validated in the same way as the TCDR

1.2.1 Surface Reflected Shortwave Radiation (SRS)

The accuracy of the SRS is determined based on the accuracy of the Surface Incoming Shortwave Radiation (SIS) from the Surface Radiation Budget brokered from EUMETSAT’s CM SAF CLARA-A2.1 dataset [D1], and the Surface Albedo (SAL), not provided within the C3S.

The accuracy for the SRS is calculated using the fixed accuracy values for the SIS ( ΔSIS = 10 W/m²) and the relative error of the SAL ( ΔSAL = 25% of the SAL value). These values are the target requirements for accuracy from CM SAF Product Requirement Document [D2]. Resulting global mean accuracy for the SRS is 7.8 W/m² for TCDR and 6.5 W/m²for ICDR. Figures 1 and 2 provide the spatial distribution of the propagated SNS accuracies.

Image Removed

Figure 1: Spatial distribution of the propagated SRS accuracies for 1982-2018 (left) and 2019-2020 (right) years.

1.2.2 Surface Net Shortwave Radiation (SNS)

The accuracy of the SNS is determined based on the accuracy of the SIS and the SAL datasets.

Estimations of the accuracy of the SIS product is given in CM SAF Validation Report [D1] and the accuracy of the SAL product is given in CM SAF Validation Report, Surface Albedo [D6].

The accuracy for the SRS is calculated using the fixed accuracy values for the SIS ( ΔSIS = 10 W/m² ) and the relative error of the SAL ( ΔSAL = 25% of the SAL value). These values are the target requirements for accuracy from CM SAF Product Requirement Document [D2]. Resulting global mean accuracy for the SNS is 13.0 W/m². Figure 2 provides the spatial distribution of the propagated SNS accuracies.

Image Removed

Figure 2: Spatial distribution of the propagated SNS accuracies for 1982-2018 (left) and 2019-2020 (right) years

1.2.3 Surface Net Longwave Radiation (SNL)

The accuracy of the SNL is defined by the accuracy of the Surface Downwelling Longwave Radiation (SDL) and the Surface Outgoing Longwave Radiation (SOL), both datasets are the Surface Radiation Budget brokered from EUMETSAT’s CM SAF CLARA-A2.1 [D1].

Estimations of the accuracy of the SDL and the SOL products are given in CM SAF Validation Report [D1].

The accuracy for the SNL is calculated using the fixed accuracy values for the SDL ( ΔSDL = 8.13 W/m² ) and the SOL ( ΔSOL = 13.77 W/m² ). Resulting global mean accuracy for the SNL is 21.9 W/m².

Global mean accuracy for the SNL ICDR is 25.0 W/m².

1.2.4 Surface Radiation Budget (SRB)

The accuracy of the SRB is defined by the accuracy of the SNS and the SNL datasets.

The accuracy for the SRB is calculated using the fixed accuracy values for the SNS ( ΔSNS = 13.0 W/m² ) and the SNL ( ΔSNL = 21.9 W/m² ).

Resulting global mean accuracy for the SRB is 34.9 W/m².

Global mean accuracy for the SNL ICDR is 39.2 W/m².

2. Validation results

2.1 Validation results for SIS, SOL, SDL

The TCDR (1982-2018) validation results are fully described in CM SAF Validation Report [D1], Section 5. The validation results for the SIS are provided in CM SAF Validation Report [D1], Section 5.2 and 5.2. The validation results for the SOL are provided in CM SAF Validation Report [D1], Section 5.3. The validation results for the SDL are provided in CM SAF Validation Report [D1], Section 5.4. Considerations for climate applications are provided in CM SAF Data Set Description [D3], Section 6. Conclusions for the validation results are provided in CM SAF Validation Report [D1], Section 6.

Results are summarised in Table 1 in the Executive Summary.

The validation results for SIS ICDR monthly and daily are fully described in CM SAF Validation Report ICDR [D8], Section 5.2.

The validation results of SOL and SDL ICDR extensions is performed within the C3S using the algorithms developed by CM SAF. The summary of validation results for the monthly ICDR SDL and ICDR SOL datasets are shown in Table 4.

At the time of writing (May 2021) only 34 out of 60 BSRN stations have submitted data for years 2019-2020. 12 stations had less than 4 month worth of data and they were discarded. A full list of BSRN stations used in the validation and stationwise results are presented in Tables 5 and 6, Section 5 Appendix of this document. The outgoing longwave measurements are performed not on all BSRN stations. Only 9 stations have submitted data for years 2019-2020. A full list of BSRN stations used in the validation and stationwise results are presented in Table 5 and 6, Section 5 Appendix of this document.

Table 4: Summary of validation results for SDL and SOL ICDR datasets (2019-2020)

...

Dataset

...

Number of months analysed

...

BSRB Stations

...

Abs.bias, W/m²

...

Std.Dev, W/m²

...

SDL, ICDR

...

404

...

24

...

15.8

...

25.16

...

SOL, ICDR

...

188

...

9

...

9.19

...

12.87

summary of validation results for the monthly ICDR SDL and ICDR SOL datasets are shown in Table 2-1.

At the time of writing (May 2021) only 34 out of 60 BSRN stations have submitted data for years 2019-2020. 12 stations had less than 4 month worth of data and they were discarded. A full list of BSRN stations used in the validation and stationwise results are presented in Tables 6 and 7, Section 5 Appendix of this document. The outgoing longwave measurements are performed not on all BSRN stations. Only 9 stations have submitted data for years 2019-2020. A full list of BSRN stations used in the validation and stationwise results are presented in Table 6 and 7, Section 5 Appendix of this document.

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	table2_1
	table2_1

Table 2-1: Summary of validation results for SDL and SOL ICDR datasets (2019-2020)

Dataset	Number of months analysed	BSRB Stations	Abs.bias, W/m²	Std.Dev, W/m²
SDL, ICDR	404	24	15.8	25.16
SOL, ICDR	188	9	9.19	12.87

2.2 Validation results for CLARA family extra data products (SRS, SNS, SNL, SRB)

The validation methodology for the extra data products is selected in a way to provide the most conservative accuracy estimation, i.e. by assuming that the uncertainties in the input datasets align perfectly and contribute fully to the overall uncertainty. Table 2 in the Executive summary provides a summary of the accuracies for the SRS, the SNS, the SNL, and the SRB. The SRS accuracy is 7.8 (6.5) W/m², the SNS accuracy is 13.0 (14.2) W/m², the SNL accuracy is 21.9 (25.0) W/m², and the SRB accuracy is 34.9 (39.2) W/m², ICDR values are in parenthesis.

3. Application(s) specific assessments

In addition to the extensive product validation (see chapter 2 for results and chapter 2/3 in [D10] for validation methodology) a second assessment is introduced to evaluate the Interim Climate Data Record (ICDR) against the Thematic Climate Data Record (TCDR) in terms of consistency. Since frequent ICDR deliveries make detailed validation not feasible, a consistency check against the deeply validated TCDR is used as an indication of quality. This is done by a comparison of the following two evaluations:

TCDR against a stable, long-term and independent reference dataset
ICDR against the same stable, long-term and independent reference dataset

The evaluation method is generated to detect differences in the ICDR performance in a quantitative, binary way with so called Key Performance Indicators. The general method is outlined in [D9] chapter 3. The same difference between TCDR/ICDR and the reference dataset would lead to the conclusion that TCDR and ICDR have the same quality (key performance is "good"). Variations or trends in the differences (TCDR/ICDR against reference) would require a further investigation to analyze the reasons. The key performance would be marked as "bad". The binary decision whether the key performance is good or bad is made in a statistical way by a hypotheses test (binomial test). Based on the TCDR/reference comparison (global means, monthly or daily means) a range is defined with 95% of the differences are within. This range (2.5 and 97.5 percentile) is used for the ICDR/reference comparison to check whether the values are in or out of the range. The results could be the following:

All or a sufficient high number of ICDR/reference differences lies within the range defined by the TCDR/reference comparison: Key performance of the ICDR is "good"
A smaller number of ICDR/reference differences is within the pre-defined range: Key performance of the ICDR is "bad"

3.1 Results

The results of the KPI test are summarized in Table 3-1.

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	table3_1
	table3_1

Table 3-1: Summary of KPI results with 2.5 and 97.5 percentiles and number of ICDR months within the range. Colors green or red mark the results of the binomial tests as good or bad, respectively.

Surface Incoming Shortwave Radiation (monthly means)

Surface Incoming Shortwave Radiation (daily means)

Surface Downwelling Longwave Radiation

Surface Outgoing Longwave Radiation

01/2019 - 06/2021

p2.5 = 5.28 W/m²

p97.5 = 14.66 W/m²

30/30

p2.5 = 5.11 W/m²

p97.5 = 11.63 W/m²

29/30

p2.5 = 8.12 W/m²

p97.5 = 25.84 W/m²

30/30

01/2019 - 12/2021

p2.5 = 5.28 W/m²

p97.5 = 14.66 W/m²

36/36

p2.5 = 8.81 W/m²

p97.5 = 40.95 W/m²

36/36

p2.5 = 5.11 W/m²

p97.5 = 11.63 W/m²

35/36

p2.5 = 7.66 W/m²

p97.5 = 25.79 W/m²

35/36

01/2019 - 06/2022

p2.5 = 5.28 W/m²

p97.5 = 14.66 W/m²

41/42

p2.5 = 8.81 W/m²

p97.5 = 40.95 W/m²

42/42

p2.5 = 5.11 W/m²

p97.5 = 11.63 W/m²

42/42

p2.5 = 6.94W/m²

p97.5 = 25.72 W/m²

42/42

Percentiles were calculated based on the comparison of the TCDR using the Advanced Very High Resolution Radiometer (AVHRR) instrument against ground-based Baseline Surface Radiation Network (BSRN) measurements for the variables Surface Incoming Shortwave Radiation (monthly means and daily means), Surface Downwelling Longwave Radiation and Surface Outgoing Longwave Radiation from 1992-2018. All products stay within the TCDR-based limits and binomial tests lead to "good" KPI performance. The ICDR is therefore stable in relation to the deeply validated TCDR.

2.2 Validation results for CLARA family extra data products (SRS, SNS, SNL, SRB)

The validation methodology for the extra data products is selected in a way to provide the most conservative accuracy estimation, i.e. by assuming that the uncertainties in the input datasets align perfectly and contribute fully to the overall uncertainty. Table 2 in the Executive summary provides a summary of the accuracies for the SRS, the SNS, the SNL, and the SRB. The SRS accuracy is 7.8 (6.5) W/m², the SNS accuracy is 13.0 (14.2) W/m², the SNL accuracy is 21.9 (25.0) W/m², and the SRB accuracy is 34.9 (39.2) W/m², ICDR values are in parenthesis.

3. Application(s) specific assessments

N/A

4. Compliance with user requirements

...

The compliance with the user requirements (as defined in the CM SAF PRD document ([D2], Section 5) for the SIS, SDL, and SOL is provided in Table 54-1.

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	table4_1
	table4_1

Table 4-1Table 5: Summary of the requirements and achieved accuracies of the brokered CLARA-A2.1 data products], Section 1 [D1 for SIS, SOL, SDL TCDR, D8 for SIS ICDR]. The accuracy estimation of SOL and SDL ICDR extensions is performed within the C3S using the algorithms developed by CM SAF

Product Name	Threshold/ Target / Optimal accuracies	Dataset accuracy [W/m²]
Product Name	Threshold/ Target / Optimal accuracies	TCDR	ICDR
SIS monthly means	15 / 10 / 8	9.5	9.6
SIS daily means	30 / 20 / 15	18.6	22.9
SDL	15 / 10 / 8	8.1	15.8
SOL	15 / 10 / 8	13.77	9.2

The validation methodology for the extra data products is selected in a way to provide the most conservative accuracy estimation, i.e. by assuming that the uncertainties in the input datasets align perfectly and contribute fully to the overall uncertainty. The SRS accuracy is 7.8 (6.5) W/m², the SNS accuracy is 13.0 (14.2) W/m², the SNL accuracy is 21.9 (25.0) W/m², and the SRB accuracy is 34.9 (39.2) W/m², ICDR values are in parenthesis.

Appendix

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	table6
	table6

Table 6: Stationwise validation results for SDL, 2019-2020

Full name	Abbreviation	#of months	Mean BSRN, W/m²	Mean CLARA, W/m²	AbsBias	RMSE	Fraction above 15 W/m²
Ny Alesund	nya	24	259,3	242,9	16,4	17,0	50
Cabauw	cab	24	323,1	318,3	4,8	5,5	0
Palaiseu Cedex	pal	10	323,1	318,7	4,5	5,4	0
Fort Peck	fpe	16	274,2	251,9	22,3	22,5	100
Payerne	pay	14	312,3	288,3	24,1	24,2	100
Sioux Falls	sxf	11	305,5	291,9	13,6	14,1	55
Sapporo	sap	22	314,9	308,9	6,4	8,2	5
Cener	cnr	23	322,3	305,5	16,8	17,5	65
Rock Springs	psu	11	323,7	311,5	12,2	13,0	27
Boulder	bos	16	280,7	229,9	50,9	50,9	100
Bondville	bon	16	315,2	308,3	7,0	7,9	0
Desert Rock	dra	16	311,1	272,8	38,3	40,2	100
Great Plains	e13	7	338,1	324,5	13,6	14,0	29
Tateno	tat	23	346	348,5	2,6	3,0	0
Goodwin Creek	gcr	16	347,5	348,8	4,9	6,0	6
Fukuoka	fua	22	354,5	353,1	2,0	2,3	0
Ishigakijima	ish	22	408,5	411,9	3,7	4,5	0
Minamitorishima	mnm	22	403,5	404,7	2,0	2,6	0
Tamanrasset	tam	24	330,6	273,8	56,8	57,0	100
Gobabeb	gob	24	338,3	327,5	11,0	11,9	17
Florinopolis	flo	22	383,5	374,7	8,8	9,0	0
De Aar	daa	11	300,4	301,2	1,6	1,9	0
Total		404	330,8	318,6	15,8	25,2	34

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	table7
	table7

Table 7: Stationwise validation results for SOL, 2019-2020

Full name	Abbreviation	#of months	Mean BSRN, W/m²	Mean CLARA, W/m²	AbsBias	RMSE	Fraction above 15 W/m²
Cabauw	cab	24	373,1	372,1	3,3	4,7	4
Concordia Station	dom	24	140,4	139,1	11,1	14,3	21
Gobabeb	gob	24	442,4	447,8	7,1	8,1	0
Georg von Neumayer	gvn	13	246,7	259,4	12,7	14,8	46
Ny Alesund	nya	24	292,6	285,8	15,8	21,2	29
Payerne	pay	14	363,9	341,4	22,5	22,9	100
Syowa	syo	24	264,2	263,5	3,1	4,0	0
Toravere	tor	17	351,4	344	7,4	9,0	12
Tateno	tat	24	394	400,2	6,4	7,6	0
Total		188	319,3	318,1	9,2	12,9	19

References

Ohmura, A., et al. (1998), Baseline Surface Radiation Network (BSRN/WCRP): New precision radiometry for climate research, Bulletin of the American Meteorological Society, 79(10), 2115-2136.

...

Further references are listed in CM SAF Validation Report [D1], Section 7.

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_{This document has been produced with funding by the European Union in the context of the Copernicus Climate Change Service (C3S)}

.The activities leading to these results have been contracted

_{, operated by the European Centre for Medium-Range Weather Forecasts}

, operator of C3S

_{on behalf}

of

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Delegation agreement

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2014

_2021).

_{All information in this document is provided "as is" and no guarantee}

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_{of warranty is given that the information is fit for any particular purpose.}

_{The users thereof use the information at their sole risk and liability. For the avoidance of all doubt, the European Commission and the European Centre for Medium-Range Weather Forecasts have no liability in respect of this document, which is merely representing the author's view.}

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General definitions

Scope of the document

Executive summary

1. Product validation methodology

1.1 Validation methodology for SIS, SOL, SDL

1.2 Validation methodology for CLARA family extra data products

1.2.1 Surface Reflected Shortwave Radiation (SRS)

1.2.2 Surface Net Shortwave Radiation (SNS)

1.2.3 Surface Net Longwave Radiation (SNL)

1.2.4 Surface Radiation Budget (SRB)

Anchorvalidationvalidation2. Validation results

2.1 Validation results for SIS, SOL, SDL

Scope of the document

Executive summary

1. Product validation methodology

1.1 Validation methodology for SIS, SOL, SDL

1.2 Validation methodology for CLARA family extra data products

1.2.1 Surface Reflected Shortwave Radiation (SRS)

1.2.2 Surface Net Shortwave Radiation (SNS)

1.2.3 Surface Net Longwave Radiation (SNL)

1.2.4 Surface Radiation Budget (SRB)

2. Validation results

2.1 Validation results for SIS, SOL, SDL

2.2 Validation results for CLARA family extra data products (SRS, SNS, SNL, SRB)

3. Application(s) specific assessments

3.1 Results

2.2 Validation results for CLARA family extra data products (SRS, SNS, SNL, SRB)

3. Application(s) specific assessments

4. Compliance with user requirements

Appendix

References

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