Some preliminary FIM results

Some preliminary FIM results

DCMIP workshopJuly/August 2012

Boulder, CO

DCMIP Test 1-1(3-D deformational flow)

Tracer advection in a 3-D time-dependent velocity field designed to return tracer to

original position after 12 days. Model dynamics disabled (active routines: cnuity, trcadv, hybgen). FIM running in pure sigma

coordinate mode60 layers; horiz mesh size ~120 km

Tracer and flow field at day 0

Vertical section along equator, showing tracer at day 0

Western hemisphereEastern hemisphere

Tracer and flow field at day 6

Vertical section along equator, showing tracer at day 6

Western hemisphereEastern hemisphere

Tracer and flow field at day 12

Vertical section along equator, showing tracer at day 12

Western hemisphereEastern hemisphere

DCMIP Test 1-2(Hadley-like meridional circulation)

Tracer advection in vertical-meridional circulation cells. Model dynamics disabled (active routines: cnuity, trcadv, hybgen). Time- and height-dependent 3-D flow

designed to return tracer to original position after 24 hrs.

FIM running in pure sigma coordinate mode30 layers; horiz mesh size ~ 240 km

Lower- and upper-level winds (left/right) at 0 hrs. Vertical resolution: 15 layers

Lower- and upper-level winds (left/right) at 24 hrs.

Vertical-meridional

section through tracer field at 0, 6, 12,18,24 hrs

DCMIP Test 1-3(advection over heavily corrugated

mountain)

Tracer advection in terrain-following coordinates. Model dynamics disabled (active routines: cnuity,

trcadv, hybgen). Time-independent horizontal flow. Schaer-type,

2km high, corrugated mountain.3 passive tracers representing low, middle, high

clouds. Advection once around the globe (12 days)

30 layers; horiz mesh size ~120km

DCMIP Test 1-3 (cont.)

Since the prescribed 2-D, nondivergent flow is inconsistent with the presence of an obstacle, the mountain is removed (“replaced by thin

air”) after the terrain-following surfaces have been defined. Their raggedness is maintained

over time with the help of the original mountaintop surface pressure.

zonal section along equator, day 0

Initial tracer position

zonal section along equator, day 0

Western hemisphere Eastern hemisphere

zonal section along equator, day 6Western hemisphere Eastern hemisphere

zonal section along equator, day 12Western hemisphere Eastern hemisphere

“low-level” cloud, day 12

“upper-level” cloud, day 12

DCMIP Test 2-0-0(atmosphere initially at rest over

heavily corrugated mountain)Spurious accelerations due to pressure gradient errors in initially motionless

atmosphere over ragged mountain complex. FIM configured with terrain-following

coordinates. Model dynamics enabled, but no rotation (f=0).

30 layers; horiz mesh size ~120km

Vertical section across mountain complex, day 2(cm/s)

Vertical section across mountain complex, day 4(cm/s)

Vertical section across mountain complex, day 6(cm/s)