CoCoRaHS: The Evolution and Accomplishments of a Volunteer Rain Gauge Network

Abstract

The Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) is a large and growing community of volunteers measuring and reporting precipitation and is making this information broadly available for the research and operational community. CoCoRaHS has evolved through several phases since its beginnings in 1998, first starting as a flood-motivated local Colorado Front Range project, then through a 5-yr nationwide expansion period (2005–09), followed by five years (2010–14) of internal growth and capacity building. As of mid-2015, CoCoRaHS volunteers have submitted over 31 million daily precipitation reports and tens of thousands of reports of hail, heavy rain, and snow, representing over 1.5 million volunteer hours. During the past 10 years, there has been wide demand for and use of CoCoRaHS data by professional and scientific users with an interest in its applicability to their different areas of focus. These range from hydrological applications and weather forecasting to agriculture, entomology, remote sensing validation, city snow removal contracting, and recreational activities, just to name a few. The high demand for CoCoRaHS data by many entities is an effective motivator for volunteer observers, who want to be assured that their efforts are needed and appreciated. Going forward, CoCoRaHS hopes to continue to play a leading role in the evolution and growth of citizen science while contributing to research and operational meteorology and hydrology.

Crowdsourcing Methods for Data Collection in Geophysics: State of the Art, Issues, and Future Directions

“…These data showed that rainfall intensity within this storm event was highly spatially varied, highlighting the importance of access to precipitation data with a high spatial resolution for flood management. In recognition of this, research communities have suggested the development of an official volunteer network with the aid of local residents, aimed at routinely collecting rainfall and other meteorological parameters, such as snow and hail (Cifelli et al, ; Elmore et al, ; Reges et al, ). More recent examples include citizen reporting of precipitation type based on their observations (e.g., hail, rain, drizzle, etc.)…”

Dual-polarized quantitative precipitation estimation as a function of range

“…Furthermore, results demonstrate the issues with analyzing QPE from a single gauge, explaining why the Community Collaborative Rain, Hail, and Snow Network (Kelsch, 1998;Cifelli et al, 2005;Reges et al, 2016) or other densely gauged networks (e.g., the Hydrometeorological Automated Data System, HADS; and the Meteorological Assimilation Data Ingest System, MADIS) tend to be more utilized since results have shown that measurements or qualitycontrolled techniques made by these organizations, especially CoCoRaHS (Community Collaborative Rain, Hail and Snow Network), are significantly more accurate than rain gauges (Simpson et al, 2017), especially for convective events (Moon et al, 2009). …”

The future of Earth observation in hydrology

“…Indeed, the de Vos et al (2017) study highlighted the additional information on the space-time variability of rainfall over a densely populated area that could be retrieved with reasonable accuracy and reliability from such a citizen network. A larger-scale example includes the Community Collaborative Rain, Hail, and Snow Network in the USA, (https://www.cocorahs.org/), which receive approximately 20 000 daily rain-gauge reports from citizen scientists across North America (Reges et al, 2016). In a particularly novel application of exploiting existing networks of data, Rabiei et al (2016) inferred rainfall by utilizing a vehicles GPS location together with sensors attached to the cars windscreen wipers.…”