Geophysical Fluid Dynamics study of naturally occuring largescale

Geophysical Fluid Dynamics “… study of naturally occuring, large-scale flows on earth and elsewhere …” Definition Large-Scale: Time Scale of Motion > Rotational Period

L~10 -m Condensation cloud as an F/A-18 Hornet flies at or near the speed of sound. Photo by John Gay

Geophysical Fluid Dynamics on Jupiter L L~10, 000 -km U~100 -m/s L/U~27 -days NASA

Jet-on-Earth: L/U ~ 10/300 s = 33 -ms Wave-on-Jupiter: L/U ~ 107/100 s = 27 -days Compare time scale to the rate of rotation ? ~ 2 / (24 hrs) ~ 2 / (10 hrs) Earth: Jupiter: Rossby Number Ro=(U/L)/ { >>1 for Jet-on-Earth <<1 for Wave-on-Jupiter

“Katrina” Aug. -2005 L~1000 -km U~30 m/s L/U~9 -hrs Ro~0. 4

Sea Surface Temperature Gulf Stream Eddies 1997

Arctic Sea Ice off Alaska Summer 2001 from MODIS Optical Remote Sensing

Mixing without rotation Mixing with rotation http: //paoc. mit. edu/labweb/GFDlab. htm

High Pressure The waves have a period of about 3 or 4 days and a wavelength of 2000 to 2500 km [1200 to 1500 mi], typically (Burpee 1974).

Atmospheric Jet Stream : http: //squall. sfsu. edu/scripts/nhemjetstream_model. html 1 Jetstream passing north of the UK bringing settled, dry and warm weather 2 Jetstream passing further south, causing weather that is unsettled and cool for the time of year

y Planetary “Rossby” Wave Dynamics z x y National Weather Service