The Fog Remote Sensing and Modeling (FRAM) Field Project and Preliminary

Results. I.Gultepe

1Cloud Physics and Severe Weather Research Section,Science and Technology Branch, Environment Canada

Toronto, Ontario, M3H 5T4, Canada

FOG FORMATION OVER SNOW

MARINE ADVECTIVE FOG

Vis=Vrh+Vliquidfog+Vicefog+Vdrizzle+Vrain+Vsnow

FRAM-LUNENBURG

Vaisala FD12P

EPPLEY radiometer

Campbell Scientific HMP45C

Young 81000 Sonic anemometer (YUSA)

MWR TP3000

DMT FMDSPP-FM

VIDEO camera

Climatronic aerosol profiler (CAP)

Vaisala CeilometerCT25K

0 500 1000 15000

0.05

0.1

Time [min]

Nif [106 m

-2s-1

] Feb 10, 2006

IPC1IPC2

Ni and VIS

0 500 1000 15000

50

100

Time [min]

Vis

ibility

[km

] Feb 10, 2006

MWR TP3000Jan 4 2006

VIDEO PROCESSING

CAP [0.3;10]

YUW [32Hz]

FT12P Vis

Marine fog (Lunenburg)

70% time during June 2006

Duration > 1 hour

Vis< 1 km

FMD fog microphysics summary

VIS VERSUS dBZ

Vis=f(RHw)

Vis=f(PR)

Vis parameterization for forecasting models

52.002.1 dLWCxNvis

RUC Vis

FOG DETECTION USING INTEGRATED DATA

FOG AREA WITH GEM

FOG AREA WITHOUT GEM

CONCLUSIONS• PARAMETRIZATION OF VISIBILITY IS

STILL IN THE QUESTION BECAUSE PARTICLES SIZES < 2-3 MICRON ARE IMPORTANT FOR EXTINCTION CALCULATIONS

• PRESENT FORECASTING MODELS (e.g. RUC MODEL) USE ONLY VIS-LWC RELATIOSHIPS THAT CAUSE LARGE UNCERTAINTIES IN VIS.

• PHYSICS, FORMATION, DEVELOPMENT, AND DISSIPATION OF MARINE AND CONTINENTAL FOGS ARE SIGNIFICANTLY DIFFERENT AND THAT NEEDS TO BE PAID MORE ATTENTION.

• PHYSICS OF FOG DROPLETS CAN HELP US BETTER UNDERSTAND NUCLEATION OF DROPLETS WITHIN THE CLOUD

INTEGRATION OF OBSERVATIONS AND DATA FROM MULTIPLE PLATFORMS ARE NEEDED TO BETTER FORECAST FOG.

OCCURRENCE OF FOG IN VARIOUS TIME AND SPACE SCALES RESULTS LIKELY UNDERESTIMATE OF ITS CLIMATOLOGY