The Comprehensive Historical Upper Air Network

The Comprehensive Historical Upper-Air Network (CHUAN) represents a global, historical upper-air dataset that has been derived from heterogeneous data available from various sources, including newly digitized data. The data have been derived from radiosondes, pilot balloons, registering balloons and kites and has been subjected to a systematic quality assessment. CHUAN has focused on collecting data for pre-1957 .

This product is the "V1.7" corrected (quality controlled) data with no bias or radiation correction applied ("CDC" in CHUAN documentation). There are other products available in "V1.7", like corrected data with bias and radiation corrections and the raw (non quality controlled) soundings, along with others, that are not available at this time. A new version is expected to be available in mid 2014.