Current WEBSITE: An Experimental Daily US Surface Water Monitor Andy W. Wood, Ali S. Akanda, and Dennis P. Lettenmaier OVERVIEW  Since April 2005, we have run an experimental real-time surface water monitoring system that uses the Variable Infiltration Capacity (VIC) macroscale hydrology model (Liang et al., 1994) for real-time estimation of soil moisture, snow water equivalent (SWE) and runoff over the continental U.S. at 1/2 degree spatial resolution.  The UW monitoring system soil moisture analyses have featured informally in US Drought Monitor synthesis discussions by the Drought Monitor authors/panel.  The UW system website maintain an archive of comparative products extending back to  The completely automated monitoring system is driven by daily precipitation & temperature minima and maxima from 2131 Coop stations, and has a 1-day update lag at the 2 p.m. PST update.  The system will eventually stage outlooks, to be updated weekly. Surface Water Monitoring System Products Andreadis, K.M., E.A. Clark, A.W. Wood, A.F. Hamlet, and D.P. Lettenmaier, 2004, 20th Century Drought in the Conterminous United States, Journal of Hydrometeorology (accepted). Liang, X., D. P. Lettenmaier, E. F. Wood and S. J. Burges, A Simple hydrologically Based Model of Land Surface Water and Energy Fluxes for GSMs, J. Geophys. Res., 99(D7). The authors acknowledge the support of NOAA/OGP and the NASA Seasonal-to-Interannual Prediction Project (NSIPP) for initial development effort. VIC Hydrologic Model (Liang et al., 1994) Comparison with Other Datasets  improving spatial resolution of the overall monitoring system to 1/8 degree.  incorporating additional products (beyond percentiles), including runoff maps, cumulative departures from normal, and recovery probabilities (derived from the outlook products) Future Plans / References /Acknowledgements Univ. of Washington Index Station Forcing Approach 1 3 Methods Examples of Current Products 5 4 From a qualitative standpoint, we find good agreement with current real-time CPC soil moisture monitoring tool Real-time Nowcasting Information Flow 2 VIC Retrospective Simulation Daily, 1915 to Near Current VIC Real-time Simulation (~1 month long) Hydrologic State Hydrologic State (-1 Day) NOAA ACIS Prcp Tmax Tmin Coop Stations NOAA ACIS Prcp Tmax Tmin Coop Stations Index Station Method Gridded Forcing Creation Index Meth. Hydrologic values, anomalies, percentiles w.r.t. retrospective PDF climatology (PDF) of hydrologic values w.r.t. defined period vals, anoms %-iles w.r.t. PDF 1930s Nowcast produced with 1-2 day lag from current 30 th Climate Diagnostics and Prediction Workshop State College, PA October, 2005 CPCUW The change in conditions over the past week, 2 weeks and 1 month help to characterize the evolving water balance. The “first-cut” implementation of the system has a limited set of products – the primary results shown currently are nowcasts (with a 1-2 day lag depending on time of day) of soil moisture and snow water equivalent percentiles. Other products are in development (see Section 5 at right). A primary goal of this system was to ensure consistency between real- time and retrospective outputs, hence the input stations were limited to those with BOTH reliable real-time reporting and historical records extending back at least 45 years. Because this results in many fewer stations than are available with less stringent criteria, we use the input stations indirectly. First, we estimate precipitation percentile (for ~month long periods) and (daily) temperature anomalies and interpolate them to a 1/2 degree grid. Then we extract corresponding values from a 1/2 degree climatological forcing PDF created using a larger set of station inputs (e.g., not all reporting in real-time, taken from the Andreadis et al. effort). Finally, temporal disaggregation of the precipitation period values is needed. Currently, the PDF is based on ; however, this choice may be revisited. Recent trends in relative soil moisture, SWE, runoff An archive from present of soil moisture and SWE percentiles on Day 1 of each month, with a simple interface for navigation In Development ARCHIVESCHANGES IN CURRENT CONDITIONS TIMESERIES ANAYSIS FOR PIXELS OR REGIONS July 2002: the western U.S. drought centers on Colorado March 1997: La Nina conditions bring the highest recorded snowfall to the PNW August 1993: the highest recorded flow on the Mississippi R. March 2002: Virginia experiences severe drought, many well failures OUTLOOKS Plots of current hydro-climatic conditions contrasted with other water years and with the daily climatological PDF. Weekly outlooks based on similar methods to those used in the UW west-wide seasonal hydrologic forecast system (using CPC, CFS, NSIPP and ESP climate ensembles). (At right are shown a sample ESP 3-month outlook initialized Febr. 1) In addition to soil moisture, current SWE and (soon) runoff percentiles climatology period (PDF) Current Products (cont.) COUNTY BLOW-UPS Clicking the main maps launches blow-up views of parts of the country showing the county delineations. Images with alternate scale bars (e.g., that match the Drough Monitor categories) are also provided