CONUS NG-IDF Data Sets

The <strong>NG-IDF data sets</strong> are developed for characterizing extreme events relevant to hydrologic design over water years 1951‒2013, at a 1/16th-degree (~6 km) resolution for over 200,000 locations across the conterminous United States (CONUS). The data sets are prepared in comma-separated value (.csv) format. <strong>The data sets include:</strong> <strong>list_location.csv</strong> <strong>Content:</strong> geographic <strong>c</strong>oordinates and (snow parameterization) cluster ID of 207,173 locations over the CONUS land surfaces. <strong>Dimension</strong>: 207,173 (Rows) x 3 (Columns) <strong>Format</strong>: <strong>C</strong>1: Latitude; <strong>C</strong>2: Longitude; <strong>C</strong>3: cluster ID (ranging from 1‒5) <strong>IDF/</strong> <strong>Content:</strong> discrete IDF values, i.e. magnitude of extreme events, corresponding to different event durations and returned periods, driven by different hydrometeorological mechanisms (i.e., rain, snowmelt, and rain-on-snow [ROS]) <strong>Dimension</strong>: 207,173 (Rows) x 9 (Columns) <strong>Format</strong>: C1: Latitude; C2: Longitude; C3‒9 (unit: mm): IDF values corresponding to return periods of 2 , 5, 10, 25, 50, 100, and 500 year <strong>trend/</strong> <strong>Content</strong>: Sen's slope of Mann-Kendall trend in annual maximum series driven by different hydrometeorological mechanisms over water years 1951‒2013 <strong>Dimension</strong>: 207,173 (Rows) x 3 (Columns) <strong>Format</strong>: <strong>C</strong>1: Latitude; <strong>C</strong>2: Longitude; C3:Trend. Unit is mm/year for all files but ROS_freq.csv that has a unit of # of events per year. <strong>Dom-Driver/</strong> <strong>Content</strong>: Dominant driving mechanism of extreme W events with different durations (24, 48 and 72 hours) and return periods (10, 50, and 100 years) <strong>Dimension</strong>: 207,173 (Rows) x 3 (Columns) <strong>Format</strong>: <strong>C</strong>1: Latitude; <strong>C</strong>2: Longitude; C3: Dominant driver IDs (1=rainfall, 2=ROS, 3=melt). <strong>risk/</strong> <strong>Content</strong>: Design risk associated with PREC-IDF estimated 100-year extreme events <strong>Dimension</strong>: 207,173 (Rows) x 3 (Columns) <strong>Format</strong>: <strong>C</strong>1: Latitude; <strong>C</strong>2: Longitude; C3: Bias (%) in PREC-IDF estimated extremes relative to NG-IDF <strong>SI/</strong> <strong>Content</strong>: Seasonality of annual maximum W events with 24-, 48-, and 72-hr durations <strong>Dimension</strong>: 207,173 (Rows) x 4 (Columns) <strong>Format</strong>: <strong>C</strong>1: Latitude; <strong>C</strong>2: Longitude; C3: Mean data (=1 if Oct 1); C4: Seasonality index <strong>Abbreviations used in folder/file names:</strong> W = water reaching the land surface during rain, snowmelt, and ROS events P = precipitation R = rainfall ROS = rain-on-snow M = snowmelt