water vapour measurments

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Liam Tallis

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Water Vapour Measurments. Liam Tallis. Introduction. Know the vertical distribution of water vapour in the atmosphere Profile for input into radiative transfer schemes Need to know this profile accurately Sources Produce a profile of water distribution in the atmosphere - PowerPoint PPT Presentation

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Page 1: Water Vapour  Measurments

Liam Tallis

Page 2: Water Vapour  Measurments

IntroductionKnow the vertical distribution of water

vapour in the atmosphereProfile for input into radiative transfer

schemesNeed to know this profile accurately

SourcesProduce a profile of water distribution in the

atmosphereExample Day: 18th September 2008

Page 3: Water Vapour  Measurments

RadiosondesDry bulb, wet bulb

and relative humidityEasy to derive lots of

other things from these

Additional launches performed during campaign

Average values for geographic area

Page 4: Water Vapour  Measurments

55.9km

52.2km

Page 5: Water Vapour  Measurments
Page 6: Water Vapour  Measurments
Page 7: Water Vapour  Measurments

Dropsondes

Dropped from FAAM aircraftRegarded as more accurate than radiosonde

Limited Height ProfileSamples relatively small geographical area

Page 8: Water Vapour  Measurments

10:26:06

08:27:43

10:28:04

10:47:56

08:32:55

10:42:33

Page 9: Water Vapour  Measurments

7.9km

Page 10: Water Vapour  Measurments

GPS Water Vapour

Page 11: Water Vapour  Measurments

HATPROHumidity and Temperature Profilers

Partial availability whilst campaign was running at Camborne

Vertical profileTemperatureRelative humidity

Page 12: Water Vapour  Measurments
Page 13: Water Vapour  Measurments

Microtops II Sunphotometer“The water vapour

measurement is based on a pair of radiometric measurements in the IR band. The 940nm filter is located in a strong water vapour absorption band, while the 1020nm filter is affected only by aerosol scattering.”

Page 14: Water Vapour  Measurments

Microtops II Sunphotometer

Page 15: Water Vapour  Measurments

Aircraft MeasurementsFAAM Aircraft has

numerous instruments on board recording information of use to use

General Eastern chilled mirror probe

Lyman-alpha total water content probe

Page 16: Water Vapour  Measurments

Numerical ModelsMet Office Model Fields

Relative Humidity (%)ECMWF Model Field

Specific Humidity (kg kg-1)

Longitude, Latitude, Pressure, Time

Need to extract the required information at each level

As useful as “real” data?

Page 17: Water Vapour  Measurments

Cross ComparisonRadiosonde

FAAM Aircra

ft

GPS Integrat

ed Water Vapour

HATPRO

Microtops

Dropsonde

Numerical

Models

Page 18: Water Vapour  Measurments

Cross ComparisonTime

Radiosonde

Microtops

GPS HATPRODropsond

eAltitud

eUT kg m-2 kg m-2 kg m-2 kg m-2 kg m-2 m             

05:00 15.8   14.6 16.5    08:28         14.9 626008:33         14.8 625009:00 14.3   13.3 15.9    09:25   12        10:26         14.8 107010:28         14 107010:42         14 910110:48         15 885011:00 15.0   14.3 16.6    11:15   13        12:00 14.3   15.6 16.3    12:35   12