Supercooled Liquid Water and Distributed Temperature Sensing Measurements from the Tethered Balloon System at the ARM AMF3

 

Authors

Darielle Dexheimer — Sandia National Laboratories
Erika Roesler — Sandia National Laboratories
Jasper Hardesty — Sandia National Laboratories
Mark D. Ivey — Sandia National Laboratories
Joseph Clinton Hardin — Pacific Northwest National Laboratory
Fan Mei — Pacific Northwest National Laboratory
Scott Tyler — University of Nevada Reno
Fred Helsel — Sandia National Laboratories
Benjamin Hillman Hillman — Sandia National Laboratories

Category

High-latitude clouds and aerosols

Description

TBS preparing for launch at ARM AMF3 in October 2016.
A tethered balloon system (TBS) has been periodically flown at the third ARM Mobile Facility (AMF3) in Oliktok Point, Alaska, since September, 2015. The AMF3 and TBS are operated by Sandia National Laboratories (SNL). The TBS was flown as part of ICARUS, the Inaugural Campaigns for ARM Research using Unmanned Systems, throughout 2016. ICARUS was an ARM initiative at Oliktok Point, Alaska, focused on developing operational routines for small Unmanned Aerial System (sUAS) and the TBS. AALCO (Aerial Assessment of Liquid in Clouds at Oliktok), is an ongoing ARM Intensive Operating Period being conducted by SNL at the AMF3, that uses in-cloud measurements from the TBS to reduce the number of unknown inputs in high-resolution Arctic cloud modeling. The TBS has operated within clouds and at altitudes up to 3,500’ AGL. While varied instruments have been deployed on the TBS, this presentation focuses on measurements from the Distributed Temperature Sensing (DTS) system and supercooled liquid water content (SLWC) sensors. The DTS uses optical fiber to measure temperature at 1 m spatial resolution and 30 s temporal resolution along the tether. The laser is fired from a ground station through the optical fiber running alongside the tether. The ratio of the Stokes and Anti-Stokes backscattered return intensities ,combined with their respective attenuations, are used to calculate temperature. Comparisons of DTS temperature measurements from the TBS with UAS, radiosonde, and other TBS temperature sensor measurements are shown. SLWC sensors have been deployed simultaneously with the DTS. The SLWC sensors employ a vibrating wire, which vibrates at a depressed frequency as ice accretes on the wire in the presence of SLW. Seasonal SLWC measurements are shown and compared with microwave radiometer and radar data. DTS and SLWC sensors were deployed under AALCO in the fall of 2016. Data were used to tune the prognostic ice concentration in the System for Atmospheric Modeling, a Large-Eddy Simulation (LES). Measurements and initial modeling results are presented.