Ground-based weather hazard information provision
The principal warning of a hazard for aircraft in flight is the SIGMET (SIGnificant METeorology) which is a coded text message typically passed by voice-over-radio by ATM personnel. Nowadays such warnings can be provided to suitably equipped aircraft through ACARS.
Conventional aviation weather hazard warning does not meet the pilots need for an accurate, timely and spatially high-resolution product.
Airborne sensors
Airborne weather sensors measure at a given detection range atmospheric parameters which are used onboard to detect and forewarn the aircrew about relevant atmospheric hazards. Additionally some parameters can be downlinked to improve the quality of local weather forecasting.
Currently, temperature and wind velocity are downlinked by the National Weather Services within the ACARS/AMDAR programme to improve weather forecasting whilst research is still ongoing for water vapour and icing downlink.
Airborne weather radar operation requires the ability to distinguish weather targets from ground targets. With current technology, this can be accomplished by a trained and skilled operator, but it requires substantial effort and expertise. This pilot and crew effort is sometimes necessary during phases of flight when the cockpit workload is already very high.
