1. Inter-Continental Atmospheric Radiosonde Upper-air Sounding System ( ICARUSS) Hal Cole, Mel Shapiro, Vin Lally, Terry Hock, Rolf Langland Surface & Sounding Systems Facility (SSSF) Atmospheric Technology Division (ATD) National Center for Atmospheric Research * (NCAR) Boulder, CO * The National Center for Atmospheric Research is sponsored by the National Science Foundation

2. NCAR / ATD / SSSF ICARUSS System Overview

3. NCAR / ATD / SSSF Balloon System Requirements l Receive and process data from each sonde deployed. l Payload of 24 GPS sondes l Operation at 50 mb to 100 mb (~18 km) l Zero-Pressure Balloon duration up to 6 days l Sondes released at programmed intervals (6 hours typical) or on command from ground station l Descent time of sonde ~24 minutes from 18 km. l Near-surface fall rate of ~8 m/s l Data generated for each sonde and sent via LEO satellites to ground station

4. NCAR / ATD / SSSF STANDARD ATMOSPHERE PRESSURE VS ALTITUDE

5. NCAR / ATD / SSSF INFLATION OF POLYETHYLENE BALLOON

6. NCAR / ATD / SSSF BALLOON BEING PREPARED FOR LAUNCH

7. NCAR / ATD / SSSF BALLOON LAUNCHED

8. NCAR / ATD / SSSF ICARUSS BALLOON LOAD VS ALTITUDE DATA

9. NCAR / ATD / SSSF STANDARD ATMOSPHERES - TEMPERATURE VS ALTITUDE POLAR TROPICAL STANDARD

10. NCAR / ATD / SSSF Flight Train Load attachment lines Parachute Satellite antenna Balloon Cut down Shock absorber Sonde receiving antenna GPS antenna Gondola

11. NCAR / ATD / SSSF Gondola Overview 4-layer Styrofoam Sonde launch tube (24) Ballast compartment (4) Electronics bay 50 cm 40 cm Cross-section

12. NCAR / ATD / SSSF ICARUSS Sonde

13. NCAR / ATD / SSSF Sonde Description l Diameter: 7.0 cm l Length: 31.75 cm l Weight: < 300 grams l Sensors: Pressure, Temperature, Humidity, Wind Speed/Direction l Sensor Update Rate: 1 Hz l Wind data derived from Navigation GPS receiver l Telemetry via 400 MHz transmitter to Balloon

14. NCAR / ATD / SSSF DROPONDE FALL VELOCITY AND TIME FOR A STANDARD ATMOSPHERE

15. NCAR / ATD / SSSF Sonde PTH Sensors l Vaisala PTH OEM Module RSS903 (same sensor module used in Vaisala’s RS90 radiosonde): l Pressure Sensor n Range:100 mb to 1060 mb n Resolution: 0.1mb n Accuracy: ± 0.5 mb * l Temperature Sensor n Range: -90° to +40° C n Resolution: 0.1° n Accuracy: ± 0.2° * l Humidity Sensor n Range: 0% to 100% n Resolution: 1% n Accuracy: ± 2% * * standard deviation of difference between two successive calibrations

16. NCAR / ATD / SSSF Sonde Windfinding l GPS Receiver: Commercial OEM GPS Receiver n Receiver Specifications –Tracks up to 12 Satellites simultaneously –L1 frequency C/A only receiver –Horizontal Winds n Range: 0 to 150 m/s n Resolution: 0.1 m/s n Accuracy: ±0.5 m/s n Position: 100 meters SEP with SA

17. NCAR / ATD / SSSF Gondola Electronics

18. NCAR / ATD / SSSF Gondola Electronics Sonde/Ballast Controller Single-Board Computer PTH Buffer 400 MHz Telemetry Receiver GPS Receiver Lithium Batteries (10) Card Chassis Satellite Transceiver

19. NCAR / ATD / SSSF ORBCOMM Satellite Coverage

20. NCAR / ATD / SSSF Estimated Costs l Total costs per balloon deployment: n 24 sondes @ $250 = $6,000 n Balloon package: $3,000 l Cost per sounding: $375

21. NCAR / ATD / SSSF Example of sounding coverage from Driftsondes deployed over Canada, Greenland & Iceland Initial Launch Time: 00 UTC 30 Nov 1999 17 launch sites Deployment Interval: 12hr Drift Level: 45 mb Coverage at: 18UTC 01Dec & 12UTC 02Dec 1999 Sea-Level Pressure

22. NCAR / ATD / SSSF Example of sounding coverage from Driftsondes deployed on the Asian Pacific rim Initial Launch Time: 00 UTC 06 Feb 1999 13 launch sites Deployment Interval: 12hr Drift Level: 100 mb 300 mb Geopotential Ht Coverage at: 18UTC 10Feb & 00UTC 11Feb 1999