Transcript Winds and height assignment

Winds and height assignment
11 October 2006
CIMSS/UW, Madison,WI
Outline
• AMV height assignment – overview
• AMV height assignment methods – CIMSS
and EUMETSAT
• Cloud Top Heights Retrieval Methods
• Open discussion and ‘[do not] Know-How’
exchange
Overview of the satellite winds derivation algorithm
CIMSS Height assignment methods (1)
ARA1/2/3
HARA1
HARA2
IR (microns!!!)IR
WV
H2O,WIN,CO2,BASE
WV
IR
WV
H2O, HIST
VIS
IR (at same sp.res.)
n/a
WIN,CO2,BASE
Nieman et al.,JAM, 1993
1. H2O−Intercept Method (H2O)
2. Infrared Window (IRW) Channel Method (WIN)
3. CO2 Slicing (or CO2−IRW) Method (CO2)
4. Water Vapor Histogram Method (HIST)
5. Cloud Base Method (BASE)
CIMSS Height assignment methods (2)
“Best" height assignment value selection:
1.The lowest pressure (highest altitude) value of all of the
calculated height values is used as the final wind vector
pressure height assignment value.
2.If WIN is selected as “best”, but a valid BASE height is
available, the BASE height will be used instead.
EUMETSAT Height assignment methods
For clouds (VIS, IR and WV channels):
1. EBBT IR Window (for VIS and IR channels), or WV for WV ch.
2. Semi_transparency Correction (6.2 channel)
3. Semi_transparency Correction (7.3 channel)
4. IR/WV Ratio method (6.2 channel)
5. IR/WV Ratio (7.3 channel)
6. CO2 Absorption (10.8 channel) representative radiance method
7. CO2 Absorption (10.8 channel) sampled radiance arithmetic method
8. CO2 Absorption (12.0 channel) representative radiance method
9. CO2 Absorption (12.0 channel) sampled radiance arithmetic method
10.RFF adjusted height. (???)
For clear sky scenes (WV channels);
1. EBBT WV Window
2. Normalised Total Cumulative Contribution Function (10% level)
3. Normalised Total Cumulative Contribution Function (50% level)
4. Normalised Total Cumulative Contribution Function (90% level)
5. Normalised Total Contribution Function (maximum level)
CTH retrieval algorithms
• GOES
– Sounder CTH (T.Schriner), VISST CTH (P. Minnis)
(spatial and temporal resolution/coverage)
– Accuracy – S.Bedka, P.Heck
• MODIS
– Operational 5km, 1 km (M.Pavolonis, R.Frey,
H.Zhang)
– Polar AMV HA – D.Santek, J.Key
• Stereo HA – GOES (F.Lu), MISR
• What else???
Discussion and ‘[do not] Know-How’ exchange
-Tracking one channel image, height assigning another channel image
-Level vs. Layer assignment
-Uncertainty introduced by model guess – BT->Press, Press->H, WIN
and HIST methods
-Spatial resolution – would it be a factor?
-(Hi , i=1,5)   (H with/w_out RFF)   (H level/layer) ???
-Updated HAM for GOES??? What channels do we have???
-CO2 with new channels – is this a hope?
Add…
• GOES-MISR-MODIS CTH comparison
• ASTER-MISR-MODIS comparison