These data are 30m by 30 m grids of the mean Standardized Precipitation-Evapotranspiration Index (SPEI) between 2001-2014 in the western United States. The SPEI index was developed by Sergio M. Vicente-Serrano and coauthors (https://spei.csic.es/index.html). Source evapotranspiration and precipitation data were generated by gridMET (http://www.climatologylab.org/gridmet.html).

Two maps, compiled at 1:1,000,000 scale, depict mean annual runoff, precipitation, and evapotranspiration in the part of the United States east of Cleveland, Ohio and north of the southern limit of glaciation. The maps are mutually consistent in that runoff equals precipitation minus evapotranspiration everywhere. The runoff map is based on records of streamflow from 503 watersheds in the United States and southernmost Canada, adjusted to represent 1951-80 and supplemented by records of precipitation at 459 stations. Precipitation at each station was partitioned into point estimates of runoff and evapotranspiration, which were constrained such that the evapotranspiration estimates varied smoothly across the region and decreased with increasing latitude and altitude, and the runoff estimates were consistent with measured runoff from nearby watersheds. A point estimate of runoff was allowed to equal mean runoff in a nearby watershed, or to be somewhat higher (or lower) if a compensating departure from mean watershed runoff could be inferred in distant parts of the watershed on the basis of altitude or regional trends. Then, precipitation contours were drawn to parallel runoff contours but differ from them by the magnitude of nearby estimates of evapotranspiration. These maps may slightly underrepresent mean precipitation and evapotranspiration in areas of high relief because most precipitation stations in such areas are in valleys. These 3 coverages were used to produce Open-File Report 96-395. Additional information about methodology can be found in this report

The standardized precipitation evapotranspiration index (SPEI) was summarized for the Upper Green River Basin to quantify climate variability over the last century. The SPEI incorporates both precipitation and temperature data, therefore the index has the capacity to include the effects of temperature variability on drought. The SPEI considers the difference between precipitation and potential evapotranspiration to calculate a climatic water balance at a given time scale (Vicente-Serrano et al. 2010). The number of standard deviations the climatic water balance deviates from the long-term mean for a given time period represents the SPEI for the time period. Here, I calculated the SPEI for each water year (Oct–Sept) between 1896 and 2017.The SPEI score is shown on the y-axis and time on the x-axis. Years in red indicate a lower SPEI than the long-term mean, whereas years in blue indicate a higher SPEI than the long-term mean. Data (4km2 SPEI data) was obtained from the Western Regional Climate Center (http:// www.wrcc.dri.edu; accessed 14 January 2017) and calculated the water year mean (12-month data) for the Upper Green River Basin. Literature Cited Vicente-Serrano, S. M., S. Beguería, and J. I. López-Moreno. 2010. A multiscalar drought index sensitive to global warming: The standardized precipitation evapotranspiration index. Journal of Climate 23:1696–1718.

Two maps, compiled at 1:1,000,000 scale, depict mean annual runoff, precipitation, and evapotranspiration in the part of the United States east of Cleveland, Ohio and north of the southern limit of glaciation. The maps are mutually consistent in that runoff equals precipitation minus evapotranspiration everywhere. The runoff map is based on records of streamflow from 503 watersheds in the United States and southernmost Canada, adjusted to represent 1951-80 and supplemented by records of precipitation at 459 stations. Precipitation at each station was partitioned into point estimates of runoff and evapotranspiration, which were constrained such that the evapotranspiration estimates varied smoothly across the region and decreased with increasing latitude and altitude, and the runoff estimates were consistent with measured runoff from nearby watersheds. A point estimate of runoff was allowed to equal mean runoff in a nearby watershed, or to be somewhat higher (or lower) if a compensating departure from mean watershed runoff could be inferred in distant parts of the watershed on the basis of altitude or regional trends. Then, precipitation contours were drawn to parallel runoff contours but differ from them by the magnitude of nearby estimates of evapotranspiration. These maps may slightly underrepresent mean precipitation and evapotranspiration in areas of high relief because most precipitation stations in such areas are in valleys. These 3 coverages were used to produce Open-File Report 96-395. Additional information about methodology can be found in this report