Data are typically provided every six to seven minutes during a flight which corresponds to about one observation every 100 kilometers. Over the past several years there has been a push to increase the frequency of observations particularly during ascent into and decent from airports. United Parcel Service and American Airlines have both begun providing high rate ascent and decent data that provides data close to the frequency of a radiosonde. United Airlines provides data every two thousand feet for ascent and decent.
There are similar programs ongoing in other regions of the world, particularly Australia, Europe and in several countries in the Asia/Pacific region. The world Meteorological Organization recognizing the need for more and improved upper air observations over the globe has established a panel to work on coordinating these regional activities as appropriate, and to expand aircraft provided weather data in data sparse regions of the world.
This paper will present an overview of the current state of commercial aircraft provided weather data, and how they fit into the composite upper air observing system.