Tristan S. L'Ecuyer of Colorado State University and Jonathan H. Jiang of the Jet Propulsion Laboratory are the co-authors of the cover story in the July issue of Physics Today, entitled "Touring the Atmosphere aboard the A-Train". The teaser caption on the cover is "Clouds, aerosols, and all that jazz", referring to the Billy Strayhorn - Duke Ellington jazz piece "Take the A-Train", which was the inspiration for the name of this unique satellite convoy in space.
The article highlights the usefulness of having data on atmospheric properties and atmospheric state acquired for the same time and location, which allows vastly improved attribution of the causes of many climate-relevant phenomena. For example, the article discusses the importance of cloud cover to Arctic sea ice extent during the summer melting season, and how pollutant aerosols influence cloud formation and rainfall intensity.
At one time, the A-Train consisted of five satellites: Aqua, CloudSat, CALIPSO, PARASOL, and Aura. PARASOL has left the formation due to lack of sufficient maneuvering fuel, but another satellite is planned to join the formation in the near future. The goal of the A-Train formation is to allow for near-simultaneous observations of atmospheric phenomena by several different sensors, providing important synergies for analysis and research insight. The satellites follow along the same orbital path, allowing for the same orbital perspective and observations separated in time by only a few minutes. Intricate orbital maneuvers keep the satellites in close proximity.
Data from the A-Train satellites is available from the GES DISC A-Train Data Depot, and many of the data products are available in the pioneering visualization and analysis interface Giovanni. The A-Train Data Depot provides direct links to the data archives, which include the GES DISC's Mirador. A-Train sensors collect data on atmospheric temperature, water vapor, rainfall, cloud layers, aerosol layers, and a variety of chemical species in the atmosphere including chloroflourocarbons, sulfur dioxide, and ozone.
A-Train Data Depot Data Access