H-SAF Product Validation Report (PVR) PR-OBS-3

More documents

Recommendations

Info

Products Validation Report, 30 May 2010 - PVR-03 (Product PR-OBS-3) Page 38 Fig. 29 - Meshed structure of the sample H02 product footprint. Determination of the W(r i,m ) weighting function in Equation 1 is crucial. In open literature, various approaches are proposed for determining this function. For instance, Thiebaux and Pedder 1987 11 suggested weightings in general as, 2 2 R ri , m forri m R 2 2 , W ( r ) R r (2) i, m 0 forr i, m i, m R where R is the radius of influence, r is the distance from centre to the point and is a power parameter that reflects the curvature of the weighting function. Another form of geometrical weighting function was proposed by Barnes 1964 12 as, ri , m W ( ri , m) exp 4 (3) R Unfortunately none of these functions are observation dependent but suggested on the basis of the logical and geometrical conceptualizations only. They are based only on the configuration, i.e. geometry of the measurement stations and do not take into consideration the natural variability of the meteorological phenomenon concerned. In addition, the weighting functions are always the same from site to site and time to time. However, in reality, it is expected that the weights should reflect to a certain extent the regional and temporal dependence behaviour of the phenomenon concerned. For the validation activities, the point cumulative semi-variogram technique proposed by Şen and Habib 1998 13 is used to determine the spatially varying weighting functions. In this approach, the weightings not only vary from site to site, but also from time to time since the observed data is used. In this way, the spatial and temporal variability of the parameter is introduced more realistically to the validation activity. 11 Thiebaux H.J. and M.A. Pedder, 1987: “Spatial objective analysis”. Academic Press, 299 pp. 12 Barnes S.L., 1964: “A technique for maximizing details in numerical weather map analysis”. J. App. Meteor., 3, pp.396-409. 13 Şen Z. and Z. Habib, 1998: “Point cumulative semivariogram of areal precipitation in mountainous regions”. Journal of Hydrology 205 (1–2), 81–91.
Products Validation Report, 30 May 2010 - PVR-03 (Product PR-OBS-3) Page 39 4. Validation of the product release as at the end of the Development Phase 4.1 Introduction This Chapter collects the results of the validation experiments as at the end of the H-SAF Development Phase. The validation is performed on the product release in force at the time of the Operations Readiness Review (ORR). The organisation was as follows: The validation period is 1 st January 2009 to 31 March 2010, in order to cover all seasons with margins. Granularity: one month. The results of the previous validation cycles, including case studies, are recorded in the Appendix to this PVR-03, reproduced from the so-called “REP-3 (H-SAF Products Validation Report)”, last issue dated 28 February 2010. The Appendix is a simple transcription of the experiments, thus it is characterised by a low level of editing, as it was appropriate to a project-internal working document. REP-3 was split in volumes, each H-SAF product being addressed by one volume. PR-OBS-3 was addressed by REP-3/04 (Results of validation activities for product PR-OBS-3). Year 2009 was addressed by REP-3/04, but the product release was not the current one. The current release, v1.4, was activated in March 2010, and data were re-processed back to 1 st January 2009. This Chapter 4 is structured by Country / Team, one section each. Each section records the main statistical scores across the January 2009 - March 2010 period, and provides comments, possibly supported by further analysis material. The next Chapter 5 (Overview of findings) provides comparative features among the results from the various Countries / Teams, so that the User of the product is informed of the variability of the performances with climatological and morphological conditions, as well as with seasonal effects. Unlike the previous validation campaigns, that placed priority to supporting the product development, thus made large use of case studies, this campaign focused on the objective of the ORR of assessing the degree of compliance of the product quality with the User requirements. For product PR-OBS-3 the User requirements are recorded in Table 07. 14 As a matter of fact, the original requirements do not specify figures for precipitation rate < 1 mm/h, since the sensing principle for PR-OBS-3 is poorly applicable to light (non-convective) precipitation. However, since the Institutes have performed validation also for light precipitation, we have added requirement figures for rate < 1 mm/h by simply extrapolating the values prescribed for more intense rates. Table 07 - Accuracy requirements for product PR-OBS-3 [RMSE (%)] Precipitation range threshold target optimal Remarks > 10 mm/h 80 40 20 1-10 mm/h 160 80 40 < 1 mm/h 320 120 80 This entry, originally N/A, has been extrapolated This formulation of the requirement implies that the main score to be evaluated is the Root Mean Square Error that, since depends on the precipitation type, or intensity, has to be evaluated with regard to the actual rate, thus RMSE (%). Supportive scores are: the ordinary RMSE (mm/h), the Mean Error (or bias, ME), and the Standard Deviation (SD). In addition, the Correlation Coefficient (CC), the Probability Of Detection (POD), the False Alarm Rate (FAR) and the Critical Success Index (CSI, necessary to compare POD - FAR coupled scores), also are reported, although rather unstable quantities for this type of geophysical parameter that does not at all comply with Gaussian characteristics. Each Country / Team should conclude its Section by listing the main features of the product, function of whatever the Team considers as a significant change of conditions associated to change of performance. The purpose is to characterise the applicability of the product for a correct use, especially in hydrology. 14 There is evidence that the user requirements for precipitation observation from space adopted by authoritative bodies (WMO, EUMETSAT, the GPM planning board) are overstated. However, currently another reference is not available. The situation will be re-assessed during CDOP-1.
Page 1 and 2: Products Validation Report, 30 May
Page 37: Products Validation Report, 30 May
Page 51 and 52: Jan'09 Jan'09 Feb'09 Feb'09 Mar'09
Page 53 and 54: Mean Error [mm/h] Mean Error [mm/h]
Page 89 and 90:
Products Validation Report, 30 May
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Precentage contribution Products Va
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Rain Rate (H-03-RG) [mm/h] Dec'07 J
Page 133 and 134:
Page 135 and 136:
GEO/IR+LEO/MW Products Validation R
Page 137 and 138:
percentage of pixels (log) Products
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149:
show all

H-SAF Product Validation Report (PVR) PR-OBS-3

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?