Challenges in obtaining reliable measurements of point rainfall

Abstract

[1] Extensive data recorded from storm systems passing over the well-instrumented 21.4 km 2 Goodwin Creek watershed in northern Mississippi are used to highlight uncertainties associated with the measurement of surface rainfall, focusing on data quality control, gauge calibration, out-of-level gauge orifices, and wind effects on rain gauge catch. Assessment of the wind effect on gauge catch is central to the presented analyses, including an in-depth evaluation of a recent technique for estimating the rainfall undercatch by means of wind and raindrop size information. Our findings emphasize that quantification of the wind effect on rain gauge catch is difficult because of uncertainties associated with measuring rainfall, drop size distribution, and the wind at gauge rim height. On the basis of our evaluation the sophisticated wind effect correction technique that makes use of raindrop size and wind information is much less effective than traditional methods based on rainfall rate and wind observations alone.

Comparison and evaluation of satellite derived precipitation products for hydrological modeling of the Zambezi River Basin

“…Therefore, as suggested in the literature (Wang and Wolff, 2010), the difference between satellite estimates and gauge measures should be separated into the gauge area-point error variance and satellite-rain estimation error variance. In another perspective, the reliability of gauge data is also controversial because the series are often not continuous and subject to many possible error sources such as mechanical problems, interferences in the sampling mechanism or inadequate calibration (Sieck et al, 2007). Since the gauge data used in this study are not exempt of inherent errors and the area-point estimation error is not taken into account, the ground data are not considered as a perfect measure but rather as a comparator for the satellite estimates.…”

Comparative rainfall data analysis from two vertically pointing radars, an optical disdrometer, and a rain gauge

“…Rain gauges are relatively inexpensive, reliable instruments, and the uncertainties associated with their observations are fairly well recognized (Habib et al, 1999(Habib et al, , 2001Sieck et al, 2007). However, due to their point-like sampling area, the degree to which they represent larger spatial scales depends on the temporal scale of integration and remains an important subject of hydrologic studies (e.g.…”

Fine-Resolution Precipitation Mapping in a Mountainous Watershed: Geostatistical Downscaling of TRMM Products Based on Environmental Variables

“…The rainfall data from 21 calibration RGS were used to calibrate the downscaled precipitation and the remaining 19 RGS were used for validation. It should be noted that there is the potential for substantial uncertainty in precipitation inferred from gauge observations as gauges in mountainous terrain often suffer significant undercatch errors due to strong winds and accessibility difficulties that can obstruct routine maintenance [71]. In this section, the original TRMM precipitation was labeled as V7 and the above-mentioned downscaled precipitation was labeled as DS.…”