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Schnur et al. 1997
Schnur, R., Krauss, T.W., Eley, F.J. and Lettenmaier, D.P. (1997). Spatiotemporal analysis of radar-estimated precipitation during the BOREAS summer 1994 field campaigns. Journal of Geophysical Research 102: doi: 10.1029/97JD00356. issn: 0148-0227.

A truck-mounted C-band precipitation radar was operated in the Boreal Ecosystem-Atmosphere Study southern study area (SSA) north of Prince Albert, Saskatchewan, for the duration of the intensive field campaigns, May to September 1994. Radar reflectivities were transformed to rainfall intensities using the Marshal-Palmer relationship at 10-min intervals for 2¿2 km pixels. Hourly accumulations of this product are analyzed for an area that coincides roughly with the southern modeling subarea (SMSA), a 50¿40 km rectangle inside the SSA where the greatest focus of field activities took place. For validation, rainfall measurements from a network of 12 tipping bucket and Belfort gauges are used. Although there are significant differences between the rainfall measurements of single gauges and the overlying radar pixels, the area-averaged (SMSA) radar rainfall coincides fairly well with the average rainfall at the gauges. The conditional mean rainfall intensity over the SSA is shown to be closely related to its standard deviation, whereas the area-averaged rain rate is related to its frequency of occurrence and rainfall coverage by power laws. The fractional area covered by rainfall above certain thresholds follows a lognormal distribution. It is demonstrated how such relationships can be used by modelers to determine the sub-grid-scale characteristics of precipitation. Using a spatially distributed hydrology-vegetation model, the effect of the spatial resolution of the rainfall fields on moisture and energy fluxes between the surface and the atmosphere is investigated. There are large differences in the modeled fluxes if only the rainfall information from the gauge network is used to produce model precipitation field inputs, as compared to using the 2¿2 km resolution radar rainfall fields. Using aggregated radar precipitation at decreasing resolutions results in increasing differences of the area-averaged fluxes from the 2¿2 km base run. In general, the mean absolute differences for area-averaged latent and sensible heat fluxes and surface runoff are less than 10%. Locally though, the effect of using lower-resolution rainfall input fields on surface energy fluxes can be quite large. ¿ 1997 American Geophysical Union

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Abstract

Keywords
Atmospheric Composition and Structure, General or miscellaneous, Hydrology, Precipitation, Hydrology, Evapotranspiration, Hydrology, Hydrologic budget
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
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