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Aschonitis, Vassilis; Papamichail, Dimitris; Demertzi, Kleoniki; Colombani, Nicolo; Mastrocicco, Micol; Ghirardini, Andrea; Castaldelli, Giuseppe; Fano, Elisa Anna (2016): High resolution global grids of revised Priestley-Taylor and Hargreaves-Samani coefficients for assessing ASCE-standardized reference crop evapotranspiration and solar radiation, links to ESRI-grid files. PANGAEA, https://doi.org/10.1594/PANGAEA.868808, Supplement to: Aschonitis, V et al. (2016): High resolution global grids of revised Priestley-Taylor and Hargreaves-Samani coefficients for assessing ASCE-standardized reference crop evapotranspiration and solar radiation. Earth System Science Data Discussions, 45 pp, https://doi.org/10.5194/essd-2016-59

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Abstract:
The database aims to provide high resolution global grids of revised annual coefficients for Priestley-Taylor (P-T) and Hargreaves-Samani (H-S) evapotranspiration methods after calibration based on ASCE-standardized Penman-Monteith method for two reference crops (ASCE method is estimated for short clipped grass and tall alfa-alfa). The analysis also includes the derivation of global grids of revised annual coefficients for estimations of solar radiation Rs using the respective Rs formula of H-S. The analysis was based on global gridded climatic data of the period 1950-2000 combining data from WorldClim database (http://www.worldclim.org/) and Princeton's Global Meteorological Forcing Dataset (http://hydrology.princeton.edu/data.pgf.php). The method for deriving annual coefficients of P-T and H-S methods was based on partial weighted averages of their mean monthly values, which eliminate the effect of monthly coefficients that occur during periods where ETo and Rs fall below a specific threshold. Five resolution global grids (30 arc-sec, 2.5, 5, 10 arc-min and 0.5 deg) of annual coefficients for each method were developed. The new coefficients were validated based on data from 140 stations located at various climatic zones of USA and Australia with expanded observations up to 2016. The validation procedure for ETo estimations of short reference crop showed that the P-T and H-S methods with revised coefficients outperformed in comparison to the typical methods reducing the ETo RMSE of estimated values by 39% and 36%, respectively. The estimations of Rs using the H-S formula with revised coefficients reduced the RMSE by 30% in comparison to the typical H-S radiation formula (the given results are based on the finer resolution grid). All the statistical criteria indicated better performance of the revised coefficients of all resolutions versus the typical coefficients used in the original methods. The overall database provides the following sub-datasets a) maps of mean monthly values of reference crop evapotranspiration for both reference crops, b) maps of revised coefficients for the ETo methods of P-T and H-S for both reference crops, c) maps of the % expected annual error of the original ETo methods of P-T and H-S versus the ASCE method for short reference crop, d) maps that indicate which of the two original ETo methods of P-T and H-S gives better results in comparison to ASCE for short reference crop, e) maps of revised coefficients for the solar radiation formula of H-S and f) maps of the % expected annual error of the original Rs method of H-S versus gridded Rs data. The provision of the database aims to support ETo and Rs estimations which are used in hydrologic/climatic applications when climate data are limited.
Related to:
Allen, Richard G; Walter, Ivan A; Elliott, Ronald; Howell, Terry A; Itenfisu, Daniel; Jensen, Marvin E (2005): The ASCE standardized reference evapotranspiration equation. In: Allen RG, Walter IA, Elliott R, Howell T, Itenfisu D, Jensen M (eds.) Environmental and Water Resources Institute. Task Committee on Standardization of Reference Evapotranspiration of the Environmental and Water Resources Institute. University of Idaho, 70 pp, hdl:10013/epic.49050.d001
Hargreaves, George H; Samani, Zohrab A (1982): Estimating potential evapotranspiration. Journal of Irrigation and Drainage Division (ASCE), 108(IR3), 225-230
Hargreaves, George H; Samani, Zohrab A (1985): Reference crop evapotranspiration from ambient temperature. American Society of Agricultural Engineers, 12 pp, http://libcatalog.cimmyt.org/download/reprints/97977.pdf
Hijmans, Robert J; Cameron, Susan E; Parra, J L; Jones, Peter G; Jarvis, A (2005): Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology, 25(15), 1965-1978, https://doi.org/10.1002/joc.1276
Priestley, C H B; Taylor, R J (1972): On the assessment of surface heat flux and evaporation using large-scale parameters. Monthly Weather Review, 100, 81-92, http://docs.lib.noaa.gov/rescue/mwr/100/mwr-100-02-0081.pdf
Sheffield, J; Goteti, G; Wood, Eric F (2006): Development of a 50-Year high-resolution global dataset of meteorological forcings for land surface modeling. Journal of Climate, 19(13), 3088-3111, https://doi.org/10.1175/JCLI3790.1
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethodComment
1ORDINAL NUMBEROrd NoAschonitis, VassilisGeocode
2File contentContentAschonitis, Vassilis
3Analytical methodMethodAschonitis, Vassilis
4CommentCommentAschonitis, Vassilis
5File nameFile nameAschonitis, Vassilis
6File formatFile formatAschonitis, Vassilis
7File sizeFile sizekByteAschonitis, Vassiliszipped
8Uniform resource locator/link to fileURL fileAschonitis, Vassilis
Size:
385 data points

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