NOAA's National Centers for Environmental Information has released a new “hydrobundle” Climate Data Record (CDR) to provide a clearer, broader picture of the hydrological aspects of Earth’s climate. This CDR, a long-term record of complementary hydrological data, includes total precipitable water, surface temperature, rainfall, sea ice, and snow, and can be used for forecasting hydrological trends and discerning changes within these climatological factors.
The hydrobundle CDR combines observations from historical and operational microwave sounding sensors and microwave humidity sounders from polar-orbiting satellites operated by NOAA and EUMETSAT (European Organization for the Exploitation of Meteorological Satellites). The record compiles more than a decade’s worth of data starting in 2001 and includes information from observation channels that primarily “see” the Earth’s surface and atmospheric water vapor. The combination of these channels allows scientists to examine various aspects of Earth’s hydrological cycles.
To develop the hydrobundle CDR, researchers had to address inconsistencies in the raw satellite data. For example, because some of the data files came from separate sensors and data streams, different approaches based on the source of the observation had to be considered to make the format of the data more consistent for use in climate studies. In essence, the data in the first 11 years of the CDR came from six different satellites, so it had to be calibrated in a consistent manner to make it seem as if it came from just one sensor. In addition, metadata from other sources had to be added to replace any data missing in the initial collection.
The process to develop the new hydrobundle record began in 2010 and was completed in 2016 by a team of developers from several parts of NOAA/NESDIS, including the Center for Satellite Applications and Research (STAR), and its Satellite Climate Studies Branch. Scientists from the University of Maryland, Cooperative Institute for Climate and Satellites (CICS), were also key contributors to the project.
Developers of the new hydrobundle say that, because the NOAA and EUMETSAT satellites are configured to observe Earth approximately every four hours, the new CDR offers a more accurate depiction of the daily hydrological cycle. Further, the data set’s insights into Earth’s hydrological systems can be extended even further when this CDR is combined with similar hydrological product suites to create a more complete and accurate data set that can be used in several ways, such as to validate climate model simulations, identify climate extremes, and validate other climatological observations. For example, a reinsurance company has successfully used the rainfall CDR to obtain a better estimate of global flooding potential as compared to estimates generated with another precipitation dataset because the latter did not provide an adequate representation of the daily precipitation.
In general, a CDR is a time series of measurements of sufficient length, consistency, and continuity to determine climate variability and change, and these record are important because they provide trustworthy information on how, where and to what extent the land, oceans, atmosphere and ice sheets are changing. Ultimately, NOAA’s CDR data, which is maintained and archived by NCEI, will improve the Nation's resilience to climate change and variability, maintain our economic vitality and improve the security and well-being of the public.
To learn more about the hydrobundle CDR, visit the NCEI website.