Insights into rainfall undercatch in differing gauge types and heights: the impact of wind speed and rainfall event intensity

Muchan, Katie; Dixon, Harry ORCID: https://orcid.org/0000-0002-1643-1046. 2018 Insights into rainfall undercatch in differing gauge types and heights: the impact of wind speed and rainfall event intensity. [Speech] In: American Geophysical Union Fall Meeting 2018, Washington, D.C., 10-14 Dec 2018. (Unpublished)

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Abstract/Summary

The measurement of rainfall has a long history, but despite its apparent simplicity it is difficult to measure accurately. The standard installation of raingauges with rims above the ground surface results in a difference between the rainfall caught and the amount reaching ground level, termed undercatch. For hydrological applications this undercatch poses problems in defining the water balance of catchments and it is therefore important to understand how it varies across different rainfall data sources. Wind patterns and rainfall intensity have been shown to impact on rainfall undercatch and variations have been observed between different gauges shape and height of the orifice rim above the ground surface. The UK standard installation of both storage and tipping bucket raingauges is for their rim to be cited at 0.3m above the ground, however the use of weighing gauges, installed at a minimum of 1m above the ground surface, has increased in recent years. The growing installation of these raingauges raises complex questions of homogeneity of rainfall data across space and time. Here, we investigate the impact of both changes, using field trials of parallel storage, tipping buck and weighing raingauges at a site in south east England. This paper will discuss the results of the field trial, exploring the variation in undercatch with differing gauge designs and citings. Investigations into the potential drivers suggest a complex relationship between undercatch, wind speed and rainfall intensity. With varying gauge heights around the world and new rainfall measurement technologies coming to the market all the time, improved understanding of undercatch is needed to inform evolving operational practices and opens up the possibility of developing catch correction algorithms to harmonise precipitation datasets.

Item Type:	Publication - Conference Item (Speech)
UKCEH and CEH Sections/Science Areas:	Water Resources (Science Area 2017-)
NORA Subject Terms:	Hydrology
Date made live:	03 May 2019 13:31 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/523185

Item Type:

Publication - Conference Item (Speech)

UKCEH and CEH Sections/Science Areas:

Water Resources (Science Area 2017-)

NORA Subject Terms:

Hydrology

Date made live:

03 May 2019 13:31 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/523185