Gio Global Land Component - Lot I QUALITY ASSESSMENT NOTE
GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 Gio Global Land Component - Lot I ”Operation of the Global Land Component” Framework Service Contract N° 388533 (JRC) QUALITY ASSESSMENT NOTE PROBA-V LAI, FAPAR, FCOVER VERSION 1 (GEOV1) Issue I2.00 Authors: Roselyne Lacaze Contributing Authors: Fernando Camacho Bruno Smets GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 Dissemination Level PU PP RE CO Public Restricted to other programme participants (including the Commission Services) Restricted to a group specified by the consortium (including the Commission Services) Confidential, only for members of the consortium (including the Commission Services) Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 X © GIO-GL Lot1 consortium Page: 2 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 Change Record Issue/Rev I1.00 Date Page(s) Description of Change 11.06.2014 All First issue: analysis performed on 4 months of I1.00 overlap with SPOT/VGT 02.10.2014 All Second issue: analysis performed on EU I2.00 summer 2014 dekads Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 Release © GIO-GL Lot1 consortium Page: 3 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 TABLE OF CONTENTS 1 Background of the document ............................................................................................... 7 1.1 Context ................................................................................................................................... 7 1.2 Scope and Objectives............................................................................................................... 7 1.3 Content of the document......................................................................................................... 7 1.4 Related documents ................................................................................................................. 8 1.4.1 1.4.2 Applicable documents .................................................................................................................................. 8 Input.............................................................................................................................................................. 8 2 Analysis............................................................................................................................... 9 3 Results .............................................................................................................................. 10 4 Conclusions and Recommendations ................................................................................... 15 Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 4 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 List of Figures Figure 1: SPOT/VGT LAI for 24 August 2013 (Top left) and PROBA-V LAI for 24 August 2014 (top right), and the difference (SPOT/VGT – PROBAV) (bottom). No clouds are detected over PROBA-V products while usual cloudy areas (Amazonia, Congo Basin, South East Asia) appear on SPOT/VGT map. Values on PROBA-V map are lower, down to -3, in the main vegetated areas of the world (East of USA, Europe and Russia, Eastern Asia, Central Africa, Indonesia). ............................................................................................................................. 11 Figure 2: LAI transect across Central Africa, from PROBA-V (white line) and SPOT/VGT (orange line). The 255 values of SPOT/VGT product indicate “no data” due to clouds. The PROBA-V profile is much noisier, probably due to strong cloud contamination, and the values are three times lower............................................................................................................................. 11 Figure 3: Temporal evolution of LAI from end of May to end of August. ........................................ 12 Figure 4: Temporal evolution, from end of May to end of August, of the difference between SPOT/VGT and PROBA-V FAPAR. ....................................................................................... 13 Figure 5: Temporal evolution, from end of May to end of August, of the difference between SPOT/VGT and PROBA-V FCover. ....................................................................................... 14 Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 5 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 List of Tables Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 6 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 1 BACKGROUND OF THE DOCUMENT 1.1 CONTEXT The GEOV1 PROBA-V products are the LAI, FAPAR, and FCover generated from the PROBAV 1km data which are first converted into SPOT/VGT-like data using a preprocessing module [GIOGL1_ATBD_PROBA2VGT] and then ingested into the GEOV1 processing chain. The PROBA-V GEOV1 products generated from November 2013 to May 2014 have been compared with the SPOT/VGT GEOV1 products produced during the same period. The results of this preliminary quality assessment showed realistic values of variables, consistent with SPOT/VGT estimates, but an excessive number of gaps due to an over-detection of clouds [GIOGL1_QANote_PROBAV-GEOV1_I1.00]. Following these outcome, it has been decided to produce, after having disabled a cloud detection criterion into the processing chain, and to disseminate the PROBA-V products from June 2014 to avoid any disruption in the GEOV1 production. Note that, due to an error configuration of the processing line, the 3 dekadss of June were produced with both PROBA-V and the last SPOT/VGT data. The usual quality monitoring performed per variable and across variables on the Jan-Jun 2014 products raised a warning about the quality of the PROBA-V GEOV1 products of June 2014: an unexpected decrease of the LAI, FAPAR and FCover values has been noted comparing to May 2014. However, a longer time period was needed to confirm this trend. 1.2 SCOPE AND OBJECTIVES The scope of this note is to present the results of the quality check carried out on the PROBA-V GEOV1 products generated in (European) summer 2014, and recommend some mitigation measures based on these results. 1.3 CONTENT OF THE DOCUMENT This document is structured as follows: Chapter 2 explains briefly the analysis Chapter 3 describes the results Chapter 4 presents the conclusions and the recommendations Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 7 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 1.4 RELATED DOCUMENTS 1.4.1 Applicable documents AD1: Annex II – Tender Specifications to Contract Notice 2012/S 129-213277 of 7th July 2012 AD2: Appendix 1 – Product and Service Detailed Technical requirements to Annex II to Contract Notice 2012/S 129-213277 of 7th July 2012 1.4.2 Input Document ID Descriptor GIOGL1_ATBD_PROBA2VGT Algorithm Theoretical Basis Document of the preprocessing module1 GIOGL1_QANote_PROBAVGEOV1_I1.00 Note presenting the results of the preliminary quality assessment of PROBA-V GEOV1 products2 1 2 http://land.copernicus.eu/global/sites/default/files/products/GIOGL1_ATBD_PROBA2VGT_I1.00.pdf http://land.copernicus.eu/global/sites/default/files/products/GIOGL1-QANote-PROBAV_GEOV1-I1.00.pdf Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 8 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 2 ANALYSIS Once available, the July and August PROBA-V GEOV1 products were analysed. They have been compared with SPOT/VGT products generated during the (European) summer of 2013, regarding the spatial and temporal patterns, variations and absolute values of variables. Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 9 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 3 RESULTS It appears clearly that: No more clouds are detected: there are no gaps in the products, even over equatorial areas known for their usual cloud coverage (Figure 1) Values of LAI are too low, comparing to the SPOT/VGT LAI of summer 2013 (Figure 1, Figure 2). The temporal variations are unrealistic, as the African tropical rainforest “disappears” from May to August (Figure 3) Differences are also noted on FAPAR with general lower PROBA-V values (down to -0.4) over all vegetated areas of the globe (Figure 4). The same trend is observed on the FCover (Figure 5) Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 10 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 Figure 1: SPOT/VGT LAI for 24 August 2013 (Top left) and PROBA-V LAI for 24 August 2014 (top right), and the difference (SPOT/VGT – PROBAV) (bottom). No clouds are detected over PROBA-V products while usual cloudy areas (Amazonia, Congo Basin, South East Asia) appear on SPOT/VGT map. Values on PROBA-V map are lower, down to -3, in the main vegetated areas of the world (East of USA, Europe and Russia, Eastern Asia, Central Africa, Indonesia). Figure 2: LAI transect across Central Africa, from PROBA-V (white line) and SPOT/VGT (orange line). The 255 values of SPOT/VGT product indicate “no data” due to clouds. The PROBA-V profile is much noisier, probably due to strong cloud contamination, and the values are three times lower. Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 11 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 Figure 3: Temporal evolution of LAI from end of May to end of August. Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 12 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 Figure 4: Temporal evolution, from end of May to end of August, of the difference between SPOT/VGT and PROBA-V FAPAR. Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 13 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 Figure 5: Temporal evolution, from end of May to end of August, of the difference between SPOT/VGT and PROBA-V FCover. Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 14 of 15 GIO-GL Lot 1, GMES Initial Operations Date Issued: 02.10.2014 Issue: I2.00 4 CONCLUSIONS AND RECOMMENDATIONS This quality control showed that the PROBA-V GEOV1 (Version 1.3) products do not reach the required level of quality necessary to be disseminated and to be used with confidence. Consequently, the PROBA-V GEOV1 production in Near Real Time has been stopped and the available products (24 May 2014 till today) were made unavailable on the product access web portal. Further, it is recommended to not use the PROBA-V LAI, FAPAR, FCover Version 1.3 for any type of application. Actions are in progress to identify the cause of the problem and to correct it, in order to allow production of PROBA-V GEOV1 to resume as soon as possible. Once the production is resumed, the available dataset (from 24 May 2014) will be re-processed to Version 1.4. Document-No. QA Note on PROBA-V LAI, FAPAR, FCover V1 Issue: Date: 02.10.2014 I2.00 © GIO-GL Lot1 consortium Page: 15 of 15
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