1. Summer Cloudtop Temps by AVHRR and Rawinsonde
LT Brady Brown, USN
OC3570 Summer 2001

2. Summer Objectives Cloud-type correlation with obs.
Low stratus measurements
vs. winter multi-layer structure.
Rawinsonde data handling & MATLAB.
Teravision image manipulation;
both for thesis preperation.
Coastal meteorology, RAOB, & skew-T;
for better understanding.

3. Procedures: Images Time Correlation: overpass & downcast delay.
Met. Conditions: foggy/clear, trajectory range.
Subtrack Distance: nadir, image stretch, geonav.
Launch Delay: concurrent events, watches.

4. Procedures: Local OPAREA
Ref: Cypress Point.

5. AVHRR Parameters Channel 4: 10.3 – 11.3 m (928 cm-1).
IFOV: 1.1 km (1.41 mrad aperture).
Brightness Temperature: K.
Data Precision: 10-bit HRPT (1024 shades).
Scan Rate: 2048 pts, 360 scan/min (16 min).
Geonavigation: boundary lock,
clearest point, Crescent City / Mt Shasta.

6. Channel 4: Spectral Response

7. Image One: 2 Aug, 2057Z, 13:57
Conditions: 7/8, “up through hole”, 311o at 5 kts.
Overpass: 2112Z (15 min late).
Subtrack: NM from Cypress Point.
Ch. 4 Temp: 12.96o C.

8. Point One

9. Image Two: 3 Aug, 2128Z, 14:28
Conditions: 8/8, 7 mi vis underneath, 333o 3 kts.
Overpass: 2101Z (27 min early).
Subtrack: NM from Cypress Point.
Ch. 4 Temp: 11.60o C (12.22o C nearby).

10. Point Two

11. Image Three: 8 Aug, 0131Z, 18:31
Conditions: clear above, fog around, 296o 4 kts.
Overpass: 0050Z (41 min early).
Subtrack: Only 15.9 NM (Best pass).
Ch. 4 Temp: 13.28o C (27o C on coastline).

12. Point Three

13. Image Four: 8 Aug, 2135Z, 14:35
Conditions: 8/8, clear just offshore, nil wind.
Overpass: 2149Z (14 min late).
Subtrack: NM.
Ch. 4 Temp: 13.07o C (constant offshore).

14. Point Four

15. Image Five: 9 Aug, 0120Z, 18:20
Conditions: 8/8, convection, 146o at 2 kts.
Overpass: 0038Z (42 min early, sonde swap).
Subtrack: NM.
Ch. 4 Temp: 11.87o C (cold patches, hot hills).

16. Related Products NRL: Cloud Type (NOGAPS > 15,000 ft)
Best for aviation OTSR, deep convective supercells.
NRL: Fog Product (4 x km cell routine)
Nightime channel 4-2 comparison.
NRL: Ash Trajectory
Daytime channel 4-5 comparison.
SCANDIA ’98: Cloud Type (shore discrepancy)
Ch. 1-2 reflectance (ice/H2O), 3-4 brightness diff.
Int’l. Sat. Cloud Clim. Proj.: D2 Cloud Type
Pressure vs Tau (optical thickness) vs Reflectance.

17. Conclusions 66 passes & 27 sondes > 11 correlated > 9 cloudy
> 5 “.mat” files > …Only 4 good matches.
Interpolate times, positions, sonde trajectories…
(45 min up/down, km travel, 82.3 m/s).
Max “delta” correlates well with surface wind.
Did not integrate “delta” over time or height
from ballon launch position of boat.
Teravision beats the pants off XVU!
(geonavigation, annotation, precision)

18. References NRL: http://kauai.nrlmry.navy.mil/sat_products.html
SCANDIA:
ISCCP: