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

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

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

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

Very good absorbers of 11mm AVHRR Only these photons reach sensor AVHRR ch 4 11 mm Very good absorbers of 11mm Emitted IR

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

Low to mid level stratoform Developing Cumuloform Thin Cirrus

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

Low Stratoform Higher Stratoform Developing Cumuloform Interesting edge

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

Mostly edges of higher clouds Cumulus congestus Tops of developing Cumulus

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

Low and mid Stratoform Developing Cumuloform

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

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

Questions?