VSA Proposal Summary
VSA title / Validation of the H-SAF precipitation products over Brazil using the CHUVA campaign datasetVSA proposal ID: / H_VS17_02 / Objective category (if applicable):
VSA Host institute: / Department of Civil Protection - Rome / Related SAF products:
VSA supervisor: / Silvia Puca / Related SAF WP: / WP6100, WPO6145, WP6300, WP6400
Expected start date: / May 2017 / Related SAF (review) processes:
Expected end date: / September 2017 / VSA costs: / 8.000 Euros (estimated as 2.5 working months at 3220 € (calculated as 50% of the average manpower rate inside the H-SAF consortium (6.440 € per month))
VS candidate: / Assigned by open call / VS / AS:
Document Approval Table
Name / Function / DatePrepared by: / Gianfranco Vulpiani / Validation Cluster member / 29/11/2016
Reviewed by: / Silvia Puca / Validation Cluster Leader / 29/11/2016
Approved by:
Document Change Record
Issue / Revision / Date / DCN. No / Summary of ChangesV0.1 / 29/11/2016 / Initial version sent to the Science Manager
V1.0
V2.0
V3.0
1Objectives and RationalE
The VS activity has to be intended as the integral part of the Federated Activity proposal entitled “Assessment of ground-reference data in Brazil and validation of the H-SAF precipitation products in the perspective of CDOP-3”that is aimed at setting up the framework for the validation of the H-SAF precipitation products on Full Disk, being a crucial task of CDOP-3.
In this contest, the main objective of the present proposal is to verify the performance of the H-SAF precipitation products on full disk using the data set collected byCPTEC/INPE the CHUVA field campaign. Detailed information on the mentioned campaign are available on
The validation of precipitation products is particularly challenging, given the highly variable nature of the precipitation fields over a wide range of spatial and temporal scales (Zawadzki, 1975; Kursinski and Mullen, 2008). This makes it difficult to set up a reliable, spatially and temporally continuous reference field, suitable to be matched to the satellite estimates: ground weather radar (Chandrasekar et al., 2008; Capacci and Porcù, 2009; Rinollo et al., 2013) and rain gauge networks (Dinku et al., 2007; Sohn et al., 2010) are mainly used to provide rainfall reference fields for validation studies. A number of studies, however, point out that care should be taken in comparing satellite and ground-based precipitation estimates for validation purposes.
A representativeness error is introduced when comparing areal instantaneous data (from satellites) with punctual cumulated values (from rain gauges) (Zawadzki, 1975; Kitchen and Blackall, 1992; Habib et al., 2009), pointing out that this error is not negligible (Porcù et al., 2014). Intrinsic discrepancies between satellite and ground radar estimates are also to be expected due to the different points of view of the two sensors (Habib and Krajeski, 2002; Chandrasekar et al., 2008; Rinollo at al., 2013).
The H-SAF Precipitation Products Validation Group (PPVG) has established a common validation protocol to deal with the mentioned issues (Puca et al., 2014).
It can be summarized through the following few steps:
a)Ground data error analysis.
b)Upscaling of radar data versus satellite native grid.
c)Temporal comparison of precipitation products (satellite and ground).
d)Statistical score (continuous and multi-categorical)evaluation.
The steps from b) to d) are accomplished through the application of a common validation code (CVC) that was developed and optimized over the years by the PPVG. The activity related to point a) is mainly carried out by the ground-data provider, leaving to a posteriori product analysis further data filtering based, whenever possible, to the application of strict quality-based constraints.
The objective of the subject VSA is to apply the CVC to the dataset collected during the CHUVA field campaign, reporting on the outcomes of the statistical analysis and providing feedback on the products accuracy to the Precipitation Cluster.
2TASKS and Methods
The tasks and methods will be defined by the candidates’ proposals, they will be considered one of the criteria of seclection for the open call.
3Deliverables
- The main deliverable will be the VS Final Report at the end of the VS, documenting arguments and results from the project activity and recommendations for future activities;
- Presentation of the results at the EUMETSAT Meteorological Satellite Conference and the H-SAF Validation meeting.
4Expected Benefits for The SAF
The proposed work is preparatory and beneficial for the assessment of the precipitation products on Full Disk, as required by the CDOP-3 proposal.
5Relation to SAF Products / Workpackages / Processes
In the CDOP2 VSA proposals are foreseen to support the Product Validation Group.
H-SAF products related to VSA: H01, H02 and H18
H-SAF CDOP-2 Work Packages: WP6100, WPO6145, WP6300, WP6400
6Dependencies
Availability of quality-controlled ground data asoutcome of the interrelated VSA activity HSAF_CDOP2_VS17_01 entitled “Testing of dual-polarization processing algorithms for radar rainfall estimation in Tropical scenarios”.
7VSA Host Institute and Supervisor
People responsible from SAF side to manage the VSA:
Silvia Puca (Validation cluster leader)
Host Institute:Department of Civil ProtectionRome, Italy
8VSA Milestones and Schedule
T0 (tentative date May 15, 2017): start of the VS
T0+2.5 months: End of the VS activity and Delivery of the Final Report.
9Summary financial information
The total cost of the VSA activity is estimated as € 8000.
10ConclusionS
A cumbersome task of CDOP-3 is dealt with through this VSA activity: the validation on full Disk of the H-SAF precipitation products. This requires the access to ground-reference data on extra European areas.Theoutcome of the interrelated VSA activityHSAF_CDOP2_VS17_01, aimed at assessing the quality of the reference data set, will be assumed as paradigm.
The subject activity would provide crucial information on the performance of the H-SAF precipitation products on Full Disk supporting the development/optimization activity in the light of the imminent beginning of CDOP-3.
Additionally, this VSA proposal would provide the opportunity to establish acooperation with the CHUVA field-experiment team that might be useful also for the optimization and extension of precipitation product on the Tropics.
The H-SAF SG is invited to approve this VSA proposal and to task the Project Team with its implementation.
References
Capacci, D. and Porcù, F.: Evaluation of a satellite multispectral VIS-IR daytime statistical rain-rate classifier and comparison with passive microwave rainfall estimates, J. Appl. Meteor. Climatol., 48, 284–300, 2009.
Chandrasekar, V., Hou, A., Smith, E., Bringi, V. N., Rutledge, S. A., Gorgucci, E., and Petersen,W. A.: Use of dual polarization radars for validation of spaceborne precipitation measurements: rationale and opportunities, Bull. Amer. Meteorol. Soc., 89, 1127–1145, 2008.
Dinku, T., Ceccato, P., Grover-Kopec, E., Lemma, M., Connor, S. J., and Ropelewski C. F.: Validation of satellite rainfall products over East Africa’s complex topography, Internat. J. Remote Sens., 28, 1503–1526, 2007.
Habib, E. and Krajewski, W. F.: Uncertainty analysis of the TRMM ground-validation radar-rainfall products: application to the TEFLUN-B field campaign, J. Appl. Meteor. 41, 558–572, 2002.
Habib, E., Larson, B. F., and Graschel, J.: Validation of NEXRAD multisensor precipitation estimates using an experimental dense rain gauge network in south Louisiana, J. Hydrol. 373, 463–478, 2009.
Kitchen, M. and Blackall, R. M.: Representativeness errors in comparisons between radar and gauge measurements of rainfall, J. Hydrol., 134, 13–33, 1992.
Kursinski, A. L. and Mullen, S. L.: Spatiotemporal variability of hourly precipitation over the Eastern Contiguous United States from Stage IV multisensor analyses, J. Hydrometeor., 9, 3–21, 2008.
Porcù, F., Milani, L., and Petracca, M.: On the uncertainties in validating satellite instantaneous rainfall estimates with raingauge operational network, Atmos. Res., 144, 73-81, doi:10.1016/j.atmosres.2013.12.007, 2014.
Puca, S., et al.: The validation service of the hydrological SAF geostationary and polar satellite precipitation products. Nat. Hazards Earth Syst. Sci., 14, 871–889, 2014.
Rinollo, A., G. Vulpiani, S. Puca, P. Pagliara, J. Kaňák, E. Lábό, Ł. Okon, E. Roulin, P. Baguis, E. Cattani, S. Laviola, and V. Levizzani, 2013: Definition and impact of a quality index for radar-based reference measurements in the H-SAF precipitation product validation. Nat. Hazards Earth Syst. Sci., 13, 2695-2705;
Sohn, B. J., Han, H.-J., and Seo, E.-K.: Validation of satellite-based high-resolution rainfall products over the Korean peninsula using data from a dense rain gauge network, J. Appl. Meteor. Climatol., 49, 701–714, 2010.
Zawadzki, I. I.: On radar-raingauge comparison, J. Appl. Meteor., 14, 1430–1436, 1975.
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