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Why We Careor

Why We Go to Sea

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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

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Satellite Algorithm Development

Courtesy Darren Jackson, CIRES, NOAA/ESRL

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Satellite Validation

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

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Ocean Model Verification

Ship vs. ModelShip track over model salinity

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Air-Sea Flux Parameterization

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Real-Time Forecast ValidationData QC

http://catalog1.eol.ucar.edu/cgi-bin/dynamo/research/date_browse?dateUTC=20111116

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2007-1999 (28 cruises)

Where does the data go?

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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

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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

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Time Scales

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Time Scales

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Time Scales

monthly weekly…. daily

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Sampling RatesThe Nyquist-Shannon sampling theorem in general states a signal can be reconstructed fromits 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.

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Accuracy / Precision Targets

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Accuracy/Precision

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An Introduction to Marine Meteorology

How does the Marine Environment differ from that over land?Homogeneity

Moisture sourceSurface frictionDiurnal cycles

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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/

http://samos.coaps.fsu.eduC % ms-1

Balloon Temperature, Humidity, and Winds

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Balloon Temperature, Humidity, and Winds

Speed

RH

Temp

Dir

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Precipitation/Clouds

24 hr Accumulated Rain Radar reflectivity

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Water Vapor 24 Oct 06Z

Satellite

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Total Precip1.3 to 5.6 mm

Time (UTC)

Precipitation/Clouds

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Precipitation

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Temperature

Air

Rain Rate

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Sea Temperature

4 Dec 1992Local Time

0

1

2

3

4

5

6

7

8

9

10

29.4 29.8 30.2 30.6 31 31.4 31.8 32.2

Temperature °C

Dep

th m 1400

1431

1641

1711

1819

1950

LocalTime

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Sea Temperature

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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

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Radiation

SW

LW

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EndLesson One