Manual

B.6. Satellite Proton Event: A proton enhancement detected by
earth orbiting satellites with a measure flux of at least 10
protons cm
-2
S
-1
ster
-1
at ≥ 10 MeV.
B.7. Polar Cap Absorption: A proton induced absorption ≥ 2dB
during daylight or ≥ .5dB during nighttime as measured by a
30 MHz riometer located within the polar cap.
B.8. Stratwarm: A major disturbance of the winter, polar, middle
atmosphere resulting from a breakdown of the polar vortex (a
polar nighttime jet stream flowing around the polar cap) into
two cells. These disturbances produce strong HF absorption
for transpolar transmission paths.
APPENDIX B: SOURCES FOR INFORMATION ABOUT
TIME AND FREQUENCY STANDARD SERVICES
Information about the geophysical alerts, marine storm warning, and
OMEGA System Status reports that are broadcast on WWV and
WWVH are available from the following sources:
Geophysical Alerts:
Space Environment Laboratory
Space Environment Services Center, R43
National Oceanic & Atmospheric Admn.
Boulder, Colo. 80302
Marine Storm Warnings:
Director
National Weather Service
Silver Spring, Md. 20910
Omega System Status Reports:
US Coast Guard HQ
(G-ONSOD/43)
Washington, D.C. 20590
Publications which describe the NIST time and frequency services
may be obtained from:
National Institute of Standard Technology 524.06 Boulder, Colo.
80303
You can ask to be placed on the mailing list for:
1. NIST Time & Frequency Bulletin issued monthly.
2. Special bulletins regarding changes in format or operating sched-
ules of NIST services, notices of upcoming events (e.g., leap sec-
Appendices
13-4
KHF 950/990 Pilots Guide
Rev. 0
Dec/96