Water Availability in Alaska: Using and Understanding NOAA s Drought Monitor and Drought Outlook

Transcription

1 Water Availability in Alaska: Using and Understanding NOAA s Drought Monitor and Drought Outlook Douglas Le Comte,, Drought Specialist, NOAA/NWS/Climate Prediction Center June 10, 2008

2 Water is Important to Communities, Industry and Ecosystems in Alaska What are NOAA s Drought Monitor and Drought Outlook and how are they made? How can we use them in planning and decision- making? Fires? Water supplies? Streamflows? What would you like to see in the drought forecasts? 2

3 How is Drought Defined? There are dozens of definitions used around the world, and no fixed, widely-accepted, objective definition exits. A generic definition: Drought is a persistent and abnormal moisture deficiency having adverse impacts on vegetation, animals, or people. (National Drought Policy Commission report, May 2000) For the U.S. Drought Monitor, we try to quantify drought as 20 th percentile ranking for a consensus of drought indices. 3

4 New NIDIS* Drought Portal drought.gov * National Integrated Drought Information System 4

5 Gateway to Drought Information Access U.S. Drought Monitor here Access Drought Outlook here 5

6 Current U.S. Drought Monitor 6

7 The Drought Monitor Concept A consolidation of indices and indicators into one comprehensive national drought map The intent is to provide an assessment product NOT a forecast! Trying to capture these characteristics: the drought s s magnitude (duration + intensity) spatial extent probability of occurrence impacts 7

8 Integrates Key Drought Indicators: - Palmer Drought Index - SPI - KBDI - Modeled Soil Moisture - 7-Day Avg. Streamflow - Precipitation Anomalies Growing Season: - Crop Moisture Index - Sat. Veg. Health Index - Soil Moisture - Mesonet data U.S. Drought Monitor In The West: -SWSI - Reservoir levels - Snowpack - Streamflow Created in ArcGIS 8

9 Continental-Scale Indicators 9

10 Importance of Hydro Power From Gwen Holdmann, Alaska Center for Energy and Power 10

11 USGS Streamflow Data About 17 real- time gages in Alaska water.usgs.gov/waterwatch/ watermonitor.gov/ 11

12 USGS Groundwater Data About 140 monitoring wells in the CONUS. Only 2 in Alaska, and only 1 real-time (Anchorage) 12

13 Monitoring Agriculture: USDA/NASS CROP WEATHER SUMMARY May 26 - June 1, 2008 DAYS SUITABLE FOR FIELDWORK: 7.0 CROP TOPSOIL MOISTURE SUBSOIL MOISTURE SHORT 10% 10% ADEQUATE 90% 90% SURPLUS 0% 0% PAN EVAPORATION FOR 05/26-06/01 MAT AES SITE: na USDA covers 3 crop areas weekly during the growing season: Tanana Valley, Matanuska Valley, and Kenai Peninsula 13

14 Precipitation Maps for Alaska Over 100 reporting stations in Alaska

15 Alaska and the Drought Monitor: The he Reality Far fewer drought indices in Alaska compared to the Lower 48 Definition of drought debatable in a cold climate Drought Monitor tries to reflect all kinds of dryness on a single map (water, agriculture, wildfire danger) Use with caution best considered as a very general indicator of dryness/drought Go to other sources for data specific to fire, water, ag. 15

16 Latest U.S. Seasonal Drought Outlook assessment.shtml 16

17 Main Features of Outlooks Show changes over next 3 to 3 ½ months for large-scale drought areas Released twice/month, 3 rd and 1 st Thursdays Initial areas based on Drought Monitor D1 areas Verification criteria based on one-category change in Drought Monitor at end of forecast period Map colors: green for improvement; brown for no change; hatched for mixed outlook; yellow for expanding drought 17

18 Principal Drought Outlook Inputs 2-Wk Soil Moisture CPC Long-Lead Precip. Outlook Constructed Analogue Soil Model Palmer 4-mo Probabilities Short-Range Fcst Medium-Range Fcst 18

19 Seasonal Streamflow Forecasts Only spring-summer forecasts available Implications for barges, fish, etc. State text info included: SNOWPACK Besides north and eastern Alaska, most snowpacks statewide have increased to reach normal or well above normal conditions as of May 1st. This is due to the cooler temperatures and continued precipitation in April. 19

20 Wildfire Forecasts I ve seen fire, and I ve I seen rain, James Taylor Alaska Interagency Coordination Center 20

21 Drought Outlooks: Short and Long Range Precipitation Forecasts Important Jun-Aug 2008 JUNE

22 The Drought Outlook and Alaska: The Reality As with the Drought Monitor, far fewer tools/guidance products available for Alaska; confidence tends to be low Forecasts are general and do not specifically address the kinds of drought hazard (fire, water, agriculture) Best to use as a very general indication of expected conditions 22

23 Working with our University Partners to Improve the Forecasts An example of a probabilistic drought forecast, defining drought as 20 th percentile of runoff. Probability of August 2008 runoff below 20 th percentile (University of WA) 23

24 Goals Make seasonal drought outlooks more objective and applicable to hydro vs ag Make outlooks more quantitative (including probabilities) Make outlooks more accurate Make outlooks more useful We d d like to know: Is this information useful? If not, how can we make it useful? 24