1. THE OKLAHOMA MESONET: EVOLUTION FROM REAL-TIME WEATHER NETWORK TO CLIMATE NETWORK Christopher Fiebrich and Kevin A. Kloesel Oklahoma Climatological Survey Norman, OK, USA

2. The Oklahoma Mesonet Commissioned in 1994 120 stations Report every 5 minutes Over 4 billion observations

3. Primarily for Real-Time Weather

4. Data Quality is Top Priority Over 4 Billion high quality observations in the Mesonet archive – Every sensor calibrated before deployed to station and re-calibrated at defined intervals – Every site visited 4 times annually on average for site maintenance, sensor testing, and metadata updates – Comprehensive automated and manual quality assurance

5. Extremes Measured in 2011 Coldest Temperature Ever Recorded in State History – 10 February 2011 – Nowata Mesonet station: -35 °C (-31 °F) – Reviewed by State Climate Extremes Committee of the National Climate Data Center

6. Record Cold

7. Extremes Measured in 2011 Highest Wind Gust Recorded in State History – 24 May 2011 – El Reno Mesonet station: 67.4 m/s (151 mph)

8. Record Wind Gust 4:20 PM LT4:25 PM LT

9. Extremes Measured in 2011 Hottest Average Monthly Temperature for Any State and Any Month – July 2011 – Statewide Average Temperature: 30.5 °C (86.9 °F) – Grandfield Mesonet site exceeded 37 °C (100 °F) on 101 days (old state record was 86 days)

10. Hottest Month in History

11. Mesonet Inclusion in COOP COOP: For more than 100 years, the U.S. COOP Network of the National Weather Service has monitored the U.S. climate The NWS began incorporating Mesonet stations in the COOP network in 2008. Today more than 70 Mesonet stations are official COOP sites

12. Mesonet Inclusion in COOP Mesonet data now included in official climate division average calculations Midnight-to-midnight observations from Mesonet eliminate the need for time of observation adjustments

13. Mesonet Continuity Sites Sensor Upgrades are Inevitable – Naturally ventilated to aspirated temperature shelters in 2008 – Relative humidity sensor (Vaisala HMP45) no longer manufactured – Evaluation of new rain gauge models – Transition to thermocouple sensors for soil temperature

14. Continuity Sites 5 stations across the state selected – Minimal impact from anthropogenic sources – Minimal impact from wind obstructions – Minimal slope – History of very high data quality – High likelihood of long-term stability Will provide long-term (multiple years) overlap of old sensor and new model

15. Continuity Sites

16. Questions?