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 Example Day: 18 th September 2008

Radiosondes Dry bulb, wet bulb and relative humidity Easy to derive lots of other things from these Additional launches performed during campaign Average values for geographic area

55.9km 52.2km

Dropsondes Dropped from FAAM aircraft Regarded as more accurate than radiosonde Limited Height Profile Samples relatively small geographical area

10:26:06 08:27:43 10:28:04 10:47:56 08:32:55 10:42:33

7.9km

GPS Water Vapour

HATPRO Humidity and Temperature Profilers Partial availability whilst campaign was running at Camborne Vertical profile Temperature Relative humidity

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.”

Microtops II Sunphotometer

Aircraft Measurements FAAM Aircraft has numerous instruments on board recording information of use to use General Eastern chilled mirror probe Lyman-alpha total water content probe

Numerical Models Met 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?

Cross Comparison Radiosonde FAAM Aircraft GPS Integrated Water Vapour HATPRO Microtops Dropsonde Numerical Models

Cross Comparison TimeRadiosondeMicrotopsGPSHATPRODropsondeAltitude UTkg m -2 m 05: : : : : : : : : : : : :35 12