CoCoRaHS

CoCoRaHS
Name	CoCoRaHS
Caption	Community-based network of precipitation observers
Formation	1998
Type	Citizen science project
Headquarters	Fort Collins, Colorado
Parent organization	Colorado State University

CoCoRaHS CoCoRaHS is a community-based network of volunteer precipitation observers that collects rainfall, snowfall, and hail data for hydrometeorological, agricultural, and climatological use. The program coordinates thousands of observers across the United States, Canada, and other countries, providing high-resolution observations to support agencies, research centers, and emergency responders. Participants use standardized equipment and digital reporting tools to contribute to national datasets used by organizations and institutions.

Overview

The network links volunteers with institutions such as Colorado State University, National Weather Service, National Oceanic and Atmospheric Administration, United States Department of Agriculture, and National Aeronautics and Space Administration to improve precipitation monitoring. It complements formal observing systems like the National Weather Service Cooperative Observer Program, Automated Surface Observing Systems, Doppler radar installations, and networks operated by Environment and Climate Change Canada and Met Office. CoCoRaHS data feeds into modeling centers at National Centers for Environmental Prediction, European Centre for Medium-Range Weather Forecasts, and research groups at universities including University of Oklahoma, University of California, Berkeley, and Iowa State University.

History and Development

Founded in 1998 at Colorado State University after catastrophic flash floods in Fort Collins flood of 1997 and influenced by programs such as the Skywarn storm spotter network, the project expanded rapidly through partnerships with state climatologists and agencies like the National Weather Association and American Meteorological Society. Early collaborations included researchers from Pennsylvania State University, University of Delaware, and University of Washington. Grants and support came from entities including the National Science Foundation, Federal Emergency Management Agency, and regional bodies such as the Upper Colorado River Commission. The network scaled through outreach at conferences like the American Geophysical Union fall meeting and by leveraging media coverage from outlets such as The New York Times, The Washington Post, and Scientific American.

Program Structure and Participation

The organizational model involves coordination among academic hosts like Colorado State University and regional coordinators tied to offices such as state climatologists in California, Texas, Florida, and New York. Volunteers receive training modeled on curricula used by National Weather Service outreach and organizations including American Red Cross and FEMA. Participants report using standardized gauges that adhere to protocols comparable to those from World Meteorological Organization guidelines. The program integrates with educational initiatives at institutions like University of Colorado Boulder, Michigan State University, and Arizona State University and partners with citizen science platforms such as SciStarter and networks like Naturalis for recruitment.

Data Collection and Methodology

Observers measure precipitation with equipment comparable to gauges used by SNOTEL and networks run by United States Geological Survey and report via web and mobile systems connected to databases used by National Oceanic and Atmospheric Administration and research centers at NOAA National Severe Storms Laboratory. The methodology emphasizes quality control through double-entry checks modeled after procedures at National Climatic Data Center and statistical verification techniques from researchers at Massachusetts Institute of Technology and Princeton University. Data are used in assimilation experiments at centers like NCAR and evaluated alongside radar products from NEXRAD and satellite retrievals from GOES and TRMM.

Applications and Impact

CoCoRaHS contributions support water resource decisions by agencies such as the Bureau of Reclamation, inform agricultural planning by the United States Department of Agriculture and extension services at universities like Ohio State University and University of Minnesota, and assist emergency management by FEMA and state emergency agencies. Researchers at Cornell University, University of Nebraska–Lincoln, and Texas A&M University have used the data for studies on extreme precipitation, drought monitoring with tools like the U.S. Drought Monitor, and urban hydrology projects linked to municipalities such as Denver, Chicago, and Los Angeles. Media and policy bodies including Environmental Protection Agency analysts, report writers at The Wall Street Journal, and climate assessors affiliated with the Intergovernmental Panel on Climate Change have cited community precipitation networks in evaluations of observational coverage.

Challenges and Criticisms

Critiques address volunteer-based sampling issues noted in discussions at forums like American Meteorological Society conferences and papers from Journal of Hydrometeorology authors at University of Illinois Urbana-Champaign and University of Georgia. Concerns include spatial bias compared to professional networks such as ASOS and representativeness relative to satellite products from MODIS and Sentinel missions operated by European Space Agency. Data quality control demands resources similar to those at National Climatic Data Center and raises governance questions debated among stakeholders including state climatologists, researchers from Rutgers University and Duke University, and practitioners at National Weather Service offices. Ongoing improvements draw on methodologies from NOAA National Centers for Environmental Information and collaborative projects with international partners like Australian Bureau of Meteorology and Met Office.

Category:Citizen science