TEC total electron count

TFCC Task Force Climate Change (Navy)

TOPEX Ocean Topography Experiment

TOR terms of reference

UAV unmanned aerial vehicle

UCAR University Corporation for Atmospheric Research

UCP Unified Command Plan

UHF ultrahigh frequency

UFO UHF Follow-on (Satellite)

UN United Nations

USCG United States Coast Guard

USCGC United States Coast Guard Cutter

USGS U.S. Geological Survey

USMC United States Marine Corps

UNCLOS United Nations Convention on the Law of the Sea

USACE U.S. Army Corps of Engineers

USN United States Navy

VDOP vertical dilution of precision

VHF very high frequency

VRIM Vulnerability-Resilience Indicators Model

WAAS wide area augmentation system

WCRP World Climate Research Program

WGS Wideband Global Satcom

WHO World Health Organization

WMO World Meteorological Organization

WRS wide area ground reference station

XBT expendable bathythermograph

XCTD expendable conductivity temperature and depth