Why We Care

1. Why We Care orWhy We Go to Sea

2. Who Uses the Data? • Shipboard personnel • Vessel operations • Ocean deployments (buoys, CTDs, towed instruments) • Science during cruise • Secondary users (not on cruise) • Ocean and atmosphere modelers • Satellite (and other remote) measurement community • Air-sea interaction researchers • Product developers (climate atlases, gridded fields) • Instrument developers

3. Satellite Algorithm Development Courtesy Darren Jackson, CIRES, NOAA/ESRL

4. Satellite Validation • Research vessel observations provide an independent assessment of biases in marine observations made by Earth-orbiting satellites (and other remote sensing platforms)

5. Ocean Model Verification Ship vs. Model Ship track over model salinity

6. Air-Sea Flux Parameterization

7. Real-Time Forecast ValidationData QC http://catalog1.eol.ucar.edu/cgi-bin/dynamo/research/date_browse?dateUTC=20111116

8. Where does the data go? 2007-1999 (28 cruises)

9. How to Measure • Know what you want to measure…..parameter(s) • Know Temporal and Spatial scales • Know sensor characteristics • Accuracy, Precision, Range, …… • Know the data acquisition system • Know the environment you will be working in

10. What to Measure • Meteorology • Wind directions and speed • Air temperature • Humidity • Pressure • Rainfall • Radiation • Oceanography • Sea temperature • Salinity • Navigation • Latitude and longitude • Course over ground • Speed over ground • Speed relative to water • Heading

11. Time Scales

12. Time Scales

13. Time Scales monthly weekly …. daily

14. Sampling Rates The Nyquist-Shannon sampling theorem in general states a signal can be reconstructed from its samples if the sampling frequency is greater than twice the highest frequency of the signal: also known as the Nyquist frequency. • Oversampling is often preferred as it: • Can aid in anti-aliasing • Can be used to increase resolution when using A/D convertors • Can also help reduce uncorrelated noise when averaging multiple samples.

15. Accuracy / Precision Targets

16. Accuracy/Precision

17. An Introduction to Marine Meteorology How does the Marine Environment differ from that over land? Homogeneity Moisture source Surface friction Diurnal cycles

18. Surface Pressure • Pressure decreases with increasing height above the surface • ~0.1 mb m-1 near the surface • At a given location, pressure varies slowly • Typical range is 990-1030 mb away from strong storms • A diurnal atmospheric tide exists with a range of ±3 mb in the tropics http://volney-bodley-weather-project.wikispaces.com/

19. Balloon Temperature, Humidity, and Winds % C ms-1

20. Balloon Temperature, Humidity, and Winds RH Dir Speed Temp

21. Precipitation/Clouds Radar reflectivity 24 hr Accumulated Rain

22. Satellite Water Vapor 24 Oct 06Z

23. Precipitation/Clouds Time (UTC) Total Precip 1.3 to 5.6 mm

24. Precipitation

25. Temperature Air Rain Rate

26. Sea Temperature Local Time

27. Sea Temperature

28. Radiation • Downwelling shortwave radiation • Most common measurement on a research vessel • Value ~1000 Wm-2 on clear day at low latitude • Short-term variations commonly identify passing clouds (or other shadows). • Downwelling longwave (infrared) radiation • Emitted by clouds and atmospheric gases • In tropics, ranges from 350-400 Wm-2

29. Radiation SW LW

30. EndLesson One