A Review of Adaptive Observations during the THORPEX Era

It has long been conceived that numerical weather forecasts will benefit from the assimilation of supplementary, “adaptive” observations that augment the conventional observational network. This concept was promoted and tested prior to and during the World Meteorological Organization / World Weather Research Programme THORPEX era (2005-2014), through field campaigns and assimilation experiments that involved numerous international collaborations. The end of THORPEX provides an appropriate opportunity to reflect on the developments, successes, and shortcomings, and to offer recommendations for advancing forecasting via adaptive observations in the future.