A Long-term hydrologically based dataset of land surface fluxes and states for the conterminous U.S.: Update and extensions

We describe a publicly available, long-term (1915 – 2010), hydrologically consistent data set for the conterminous United States, intended to aid in studies of water and energy exchanges at the land surface. These data are gridded at a spatial resolution of 1/16 degree latitude-longitude and are derived from daily temperature and precipitation observations from approximately 20,000 NOAA Cooperative Observer (Co-op) stations. The available meteorological data include temperature, precipitation, and wind, as well as derived humidity and downwelling solar and infared radiation estimated via algorithms that index these quantities to the daily mean temperature, temperature range, and precipitation, and disaggregate them to three-hourly time steps. Furthermore, we employ the Variable Infiltration Capacity (VIC) model to produce three-hourly estimates of soil moisture, snow water equivalent, discharge, and surface heat fluxes. Relative to an earlier similar data set by Maurer and others, we have: a) extended the period of analysis (1915-2010 versus 1950-2000), b) increased the spatial resolution from 1/8° to 1/16°, and c) used an updated version of VIC. The previous data set has been widely used in water and energy budget studies, climate change assessments, drought reconstructions, and for many other purposes. We anticipate that the spatial refinement and temporal extension will be of interest to a wide cross-section of the scientific community.