Climate Information for Managing Risk. Victor Murphy NWS Southern Region Climate Service Program Mgr. June 12, 2008

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Elinor Hudson
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1 Climate Information for Managing Risk Victor Murphy Climate Service Program Mgr. June 12, 2008

2 Currently From Fort Worth, TX

3 but climate challenges abound everywhere

4 as does the need to mitigate impacts and improve resiliency by providing decision makers with timely info in user friendly formats.

5 NWS Precipitation Analysis Precipitation variability is one of the key challenges to defining climate variability. Info must be accurate and timely and displayed in a format that is user friendly for decision makers to declare droughts or burn bans or disaster declarations when compared to climatological norms.

6 ...however.at the same time the needs of researchers and the climate application community must be met.

7 NWS Precipitation Analysis Product

8 Precipitation Analysis Product Many user groups are interested in high quality precipitation estimates with proper spatial resolution.

9 Precipitation Analysis Product Measuring and displaying observed precipitation amounts in a user friendly format is a fundamental precept of any kind of climate application. Accurate Precipitation Analysis or Estimates must follow a multi sensor approach. Individually, each method of determining precipitation totals has its inherent weaknesses.

10 Precipitation Analysis Product In situ gauge problems include: Wind Tipping bucket losses Siting (blockage from buildings, trees, plants) Frozen Precip Electronic signal malfunctions Mechanical problems Bird Nests/blockages Timing and Coding Issues

11 Precipitation Analysis Product In situ gauges also suffer from lack of spatial resolution or coverage. Even the most ambitious of mesonets will be fortunate to have one precipitation reporting site per county.

12 NWS Co-Op Data Sites in Alachua County

13 969 square miles two official reporting sites

NWS Doppler Radars Offer Spatial Density Brief explanation of how radar estimates rainfall Radar sends out beam of electromagnetic energy A small amount of this

14 NWS Doppler Radars Offer Spatial Density Brief explanation of how radar estimates rainfall Radar sends out beam of electromagnetic energy A small amount of this energy returns to the radar (measured in decibels or dbz) from raindrops and is called reflectivity Z A relationship assigns a rainfall rate R to the reflectivity Z (Z/R)

15 Precipitation Analysis Product

16 Precipitation Analysis Product We run a program called Multi Sensor Precip Estimator (MPE) every hour. We bias radar data using hourly rain gauges. After all the biases are checked, all the rain gauges have been quality controlled, all the AP has been removed, we save that hours estimates. This becomes our Best Estimate field. But remember these are still estimates. How do we know if they are close?

17 Precipitation Analysis Product We zoom in on an area of interest and display the 24-hour COOP and CoCoRaHS rain gauge data. We consider the 24-hour quality controlled (or manually read) rain gauge data to be our best.

18 Precipitation Analysis Product We can click on any of the rain gauges to show the precip data site. It tells us what the rain gauge value is, what the MPE value is at the location of the gauge, and the MPE value where we clicked our cursor.

19 Precipitation Analysis Product Direct comparisons can now be made between what we estimated the rain to be (based on biased radar from MPE) and rain gauge data.

20 Precipitation Analysis Product Thru the use of hourly MPE, precipitation values are calculated nationally using 4km x 4km grids. These 4km x 4km grids are then added together to create a daily 24 hourly precipitation estimate valid at 1200GMT. They are stored in net.cdf files allowing external users to download the files for local applications.

21 Precipitation Analysis Product The precipitation value assigned to each grid is the centroid location when shipped via a net.cdf file. 24 hour values can then be summed to create user selectable daily, weekly, 2 week, monthly, etc., products. Value added products include departures from normal and percent of normal precipitation using PRISM derived data as the normal data set.

22 Precipitation Analysis Product Users have a GIS format method for selecting the time frame, region of the country, or state for which they want to view the data. User selectable parameters include counties, cities, major highways, and rivers.

23 Precipitation Analysis Product Historical data currently goes back to Emphasis on taking this back earlier. Initial product available at approx 1400GMT daily. Final product available at approx 1900GMT daily.

25 Day 1 Precipitation

26 May 2008 Observed Precip

27 PRISM derived 30 day normal precipitation

28 May 2008 Departure from Normal

29 May 2008 % of Normal

30 Iowa 30 day Precipitation

31 Iowa 30 day departures

32 4km resolution of the KBDI in Florida

33 County Average KBDI for Florida

34 4km x 4km KBDI

35 Alabama Lawn/Garden Moisture Index

36 Thank You! Victor Murphy x 130

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