ALTOSSUPP

NOTE: An unfortunate incident in the early stages of ALTOS (October 2010) has resulted in the campaign being terminated. During one of the tethered balloon's initial flights, its primary and secondary tethers broke, and the instrument payload landed in the ocean where it could not be safely retrieved. If replacement instruments can be obtained in the next few months, there is a possibility the campaign could restart in the spring.

A millimeter cloud radar (MMCR) and a depolarization lidar will be added to the instrument complement during the ALTOS campaign. In addition, our hope would be to add a High Spectral Resolution Lidar, although any lidar would be a significant addition. At the time of submission of the original ALTOS proposal, no such spare instruments were available in the ARM program. However, with the removal of the radar and lidar from Nauru and the acquisition for new instruments through the Recovery Act funding, the possibility now at least exists.

The addition of an MMCR would add great value to the experiment. First, as reviewers of the ALTOS proposal pointed out, an MMCR at Oliklok Point will allow direct comparison between the in situ tethered balloon system measurements and radar retrievals. This comparison would allow us to investigate in greater detail the differences arising from the statistical comparison with the Barrow MMCR. Such conditions represent significant challenges to current retrieval schemes based on moments, but represent great insight into the microphysical processes controlling the lifetime and evolution of these mixed-phase clouds.

Timeline