VALCLRADAR

The Storm Peak Lab Cloud Property Validation Experiment (STORMVEX)

15 November 2010 - 25 April 2011

Lead Scientist: Gerald Mace

Observatory: AMF, SBS

The core goals of the ARM Climate Research Facility included improving the representation of clouds in global models. To accomplish this goal, ARM invested considerably in creating long-term data sets from suites of ground-based remote sensors placed at climatically important locations around the world. However, the ability to convert the remote sensing measurements to cloud properties has been hampered by a critical shortage of correlative data that could be used for validation and development of new algorithms. Such correlative data sets are normally created by episodic and expensive aircraft measurements. The field deployment of the second ARM Mobile Facility (AMF2) provided the potential to create a correlative data set equivalent to between 200 and 300 aircraft flights in liquid and mixed phase clouds. This was achieved by placing the AMF2 in close proximity to an elevated platform that was heavily instrumented with aerosol, cloud and precipitation sensors. The Storm Peak Lab (SPL), located east of Steamboat Springs, Colorado, is a well-established cloud and aerosol research facility operated by the Desert Research Institute. SPL is located at 3210 meters above sea level and is above cloud base 25 percent of the time during the winter season. The already extensive instrument suite at SPL was augmented with additional state-of-the-art instruments that are typically used for airborne cloud research by the Stratton Park Engineering Corporation (SPEC). SPL and SPEC collected in situ cloud and precipitation property measurements while the AMF2 operated at a location approximately 2.4 kilometers west and 2078 meters in elevation during a winter season. This deployment addressed three long-standing ARM objectives:

• From a cloud property retrieval perspective, the type of clouds that were observed during this period ranged from stable liquid phase boundary layer clouds to mixed phase clouds to heavily precipitating snow. These cloud types represented some of the most unique challenges for cloud property retrievals and the full Doppler spectra from the scanning cloud radar combined with other AMF2 measurements correlated with continuous in situ data facilitated development of new algorithms and statistically significant validation of the algorithm results.
• The data set was collected in a region of complex terrain. Collecting such a data set has been a long standing goal of ARM and presented a unique challenge and opportunity for modeling groups.
• The extensive aerosol data set that was collected at SPL allowed for investigation of the role of natural and anthropogenic aerosol in cloud and precipitation processes.