1. GIS and Drought Applications Keith Stellman Senior Hydrologist Lower Mississippi River Forecast Center Slidell, LA

2. Outline Overview of CPC products History/Background info/Examples Validity of the Data Gridded Normals? Compositing Possibilities

3. Normal CPC Drought Graphics

4. CPC Graphics Cont’

5. CPC Graphics Cont.

6. Overview / History Stage III –4 x 4 km resolution –Gridded PRISM data ABRFC –Computed daily average from PRISM data –Posted output images to web LMRFC –Converted prism grids to HRAP projection in GIS –Computed monthly images on 1 st of the month

7. CPC Percent of Normal

8. RFC Graphics 1 Month Stage III

9. RFC Graphics

10. WGRFC/ABRFC/OHRFC Examples

11. Detailed RFC Images

12. Details, Details County to county rainfall surplus/deficits Grid to grid comparisons Water supply issues from county to county

13. RFC Observed Analysis Daily rain gage analysis in GIS using IDW method of interpolation on 4x4 km grid Grids are archived Grids are summed for monthly totals Rain gage analysis can then be used for percent of normal

14. Observed Analysis 1 Month Totals

15. LMRFC Observed Analysis

16. Comparisons Minimums

17. How Accurate is the Data? 1 month totals for October 2002 ASOS IDStage III Estimate Gage Analysis Estimate ASOS Monthly Total LCH21.0221.4521.27 LFT17.4318.2718.35 AEX14.1912.4913.37 LIT5.145.095.07 MEM8.498.288.41

18. What is Normal? PRISM (Parameter-elevation Regressions on Independent Slopes Model) Knowledge-based system using point data, digital elevation model, & other spatial data sets Generates gridded estimates of climatic parameters (such as precipitation & temperature) Accounts for rain shadows, inversions, coastal proximity, and others

19. Orographic Enhancement

20. PRISM Maps

21. Where Can I Find PRISM Data?  Digital via Web Sites SCAS: www.ocs.orst.edu/prism/ NRCS: www.ftw.nrcs.usda.gov/prism/prism.htmlwww.ftw.nrcs.usda.gov/prism/prism.html Contact Info: Christopher Daly Director Spatial Climate Analysis Service Oregon State University Corvallis, Oregon

22. How do we get the results PRISM data is on a 4x4 km grid Stage III data is on a 4x4 km grid ((((StageIII-Prism)/Prism)+1)*100) = % of Normal Precipitation GIS Software does grid calculations and exports result as a JPEG Program is automatically run on 1 st of the month for previous 1,2,3 and 6 months

23. Who is doing what? ABRFC,WGRFC,LMRFC,OHRFC,CBRFC –Utilize gridded datasets CBRFC lists under water supply in form of pdf document MBRFC,NERFC and MARFC –Utilize observed datasets on larger scale MBRFC uses pdf document under water supply

24. Composite Southern Region RFC Web Team –Goal is to composite graphics with levels of zoom Each SR RFC (SERFC,WGRFC,LMRFC,ABRFC) sends daily StageIII totals to WGRFC Data is summed into monthly totals and compared to PRISM data

25. Coming Very Soon!

26. Future Possibilities Providing each monthly calculation as a shapefile or ascii grid Incorporating more than SR RFC’s into the datasets Utilizing gage only datasets across SR