1. Identifying cloud layers on Rawinsondes and IR satellite images
LCDR Jim Rocha
18 March 2001

2. Identifying cloud layers on Rawinsondes and IR satellite images
Objectives of project were to gain experience in:
Rawinsonde operations and interpreting the data
Working with NOAA-14 (16) AVHRR satellite imagery
Using Teravision satellite image processing software
Learn a little more about the atmosphere

3. Procedure:
Examine Rawinsonde temperature and humidity profiles for distinguishing characteristics
Attempt to identify possible cloud layers
Examine AVHRR channel 4 images and try to identify the same layers
Isolate the identified layers and produce new images

4. Problems:
Original plan was to compare cloud top temperature between AVHRR and Rawinsondes
Satellite image time of op area spans 16 minutes
Rawinsonde flight time as much as 45 minutes
Rawinsonde movement as much as 90 km at speed of up to 120 mph
Result of all these variables: Impossible to co-locate individual clouds between Rawinsonde location and satellite image location time

5. Very good absorbers of 11mm
AVHRR
Only these photons
reach sensor
AVHRR ch mm
Very good absorbers of 11mm
Emitted IR

6. (RS11) Layers Examined: 2069 to 2840 meters -5.7 to –9.5o C

7. Low to mid
level stratoform
Developing
Cumuloform
Thin Cirrus

8. (RS18) Layers Examined: 532 to 1560 meters 3.7 to -2.5o C

9. Low
Stratoform
Higher
Stratoform
Developing
Cumuloform
Interesting
edge

10. (RS19) Layers Examined: 561 to 1258 meters 3.6 to -2.1o C

11. Mostly edges of
higher clouds
Cumulus
congestus
Tops of
developing
Cumulus

12. (RS20) Layers Examined: 661 to 1543 meters 3.0 to –4.4 o C

13. Low and mid
Stratoform
Developing
Cumuloform

14. Conclusions:
Difficult to accurately identify individual layers completely due to shadowing in IR imaging by higher cloud layers
Some basic correlation can be shown between Rawinsonde humidity layers and imaged layers
No real scientific findings achieved

15. Identifying cloud layers on Rawinsondes and IR satellite images
Objectives of project were to gain experience in:
Launching Rawinsondes, retrieving and interpreting data
Working with NOAA-14 (16) AVHRR satellite imagery
Using Teravision image processing software
Learn a little more about the atmosphere
By-product of project… more MATLAB practice

16. Questions?