Essential Climate Variables (ECVs) are critical variables whose measurement helps scientists monitor and understand climate behavior, changes, and impacts, much like vital signs in human health. They are chosen based on relevance, feasibility, and cost-effectiveness, ensuring they provide key insights into the global climate system.
Examples of ECVs include atmospheric variables (temperature, precipitation, wind), land variables (soil carbon, river discharge, leaf area index), and ocean variables (sea surface temperature, salinity, phytoplankton). The Global Climate Observing System (GCOS) organizes these to provide a standardized framework for global climate data collection and sharing.
In-situ measurements involve collecting data directly from the point of interest, such as using thermometers for temperature or rain gauges for precipitation. They provide reliable data but can be limited by geographic coverage, especially over oceans.
Ocean measurements often rely on buoys and ships but are supplemented by the Argo program, which uses floats to measure temperature and salinity at various depths. Despite the network of about 4,000 floats, gaps remain, especially in remote ocean areas and deep ocean zones.
Remote sensing via satellites allows for continuous global monitoring of ECVs. Polar-orbiting satellites provide detailed snapshots of different Earth regions, while geostationary satellites monitor the same area continuously. Both types are essential for a comprehensive climate record.
The National Centers for Environmental Information (NCEI) manages U.S. climate data and collaborates with regional centers to support research, public outreach, and informed decision-making.
Citizen science initiatives like CoCoRaHS involve volunteers reporting local precipitation to fill gaps in traditional climate observation networks, enhancing data coverage and accuracy.