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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #419477
Research Project: Science and Technologies for Improving Soil and Water Resources in Agricultural Watersheds

Location: Watershed Physical Processes Research

Title: USDA LTAR common experiment measurement: Rainfall measurements

Author
item DUBOSE, RACHEL - Us Geological Survey (USGS)
item O'Reilly, Andrew - Andy
item Witthaus, Lindsey
item Baffaut, Claire

Submitted to: Protocols.io
Publication Type: Research Notes
Publication Acceptance Date: 10/3/2024
Publication Date: 10/3/2024
Citation: Dubose, R., O'Reilly, A.M., Witthaus, L.M., Baffaut, C. 2024. USDA LTAR common experiment measurement: Rainfall measurements. Protocols.io. https://doi.org/10.17504/protocols.io.e6nvw1kyzlmk/v1.
DOI: https://doi.org/10.17504/protocols.io.e6nvw1kyzlmk/v1

Interpretive Summary: This protocol is part of a larger set published at protocols.io for the LTAR Common Experiment. This protocol outlines how to measure rainfall. These measurements are important to agriculture because they are required in order to calculate rainfall flux, defined as the liquid water component of precipitation, which affects the growth of crops and the influence of crop production on the surrounding environment. The goal is to provide repeatable guidelines to achieve consistent data collection, instrument maintenance, data processing, and quality control for obtaining these data at cropland sites across the U.S.

Technical Abstract: Rainfall includes any moisture falling from the atmosphere in liquid form. Rainfall is often called precipitation, but precipitation includes liquid water as well as a solid water such as snow fall. The rainfall measurement protocol addresses the measurement of only liquid precipitation. The snow metrics measurement protocol describes how to measure snowfall. The total amount of rainfall reaching the ground in a given period is described as a depth over a given area, assuming no loss by evaporation, plant interception, or runoff. Rainfall is an essential input, with much of the world relying on it for agricultural production. There is evidence that rainfall patterns and intensity are changing, which affects the sustainability of agroecosystems and soil erosion rates. Rain gauges are the most effective method for measuring liquid precipitation. The recommended method for measuring rainfall is through a network of recording rain gauges, which measure the time and amount of liquid precipitation. Alternatively, catch gauges are applicable, but they will typically not yield the time and rate of rainfall, and thus, they are not recommendable. The area and spatial variability of rainfall will determine how many gauges are needed. Generally, more rain gauges distributed within a given region are preferable, although geographical and economic constraints can limit gauge density and placement. Recently, automated methods for determining optimum rain gauge placement within a region have been published (Di et al. 2020).