First observations of tracking clouds using scanning ARM cloud radars

Journal Article · Mon Dec 01 04:00:00 UTC 2014 · Journal of Applied Meteorology and Climatology

DOI: https://doi.org/10.1175/JAMC-D-13-0182.1 · OSTI ID:1182525

Borque, Paloma ^[1]; Giangrande, Scott ^[2]; Kollias, Pavlos ^[1]

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1. McGill Univ., Montreal, QC (Canada)
2. Brookhaven National Lab. (BNL), Upton, NY (United States)

Tracking clouds using scanning cloud radars can help to document the temporal evolution of cloud properties well before large drop formation (‘‘first echo’’). These measurements complement cloud and precipitation tracking using geostationary satellites and weather radars. Here, two-dimensional (2-D) Along-Wind Range Height Indicator (AW-RHI) observations of a population of shallow cumuli (with and without precipitation) from the 35-GHz scanning ARM cloud radar (SACR) at the DOE Atmospheric Radiation Measurements (ARM) program Southern Great Plains (SGP) site are presented. Observations from the ARM SGP network of scanning precipitation radars are used to provide the larger scale context of the cloud field and to highlight the advantages of the SACR to detect the numerous, small, non-precipitating cloud elements. A new Cloud Identification and Tracking Algorithm (CITA) is developed to track cloud elements. In CITA, a cloud element is identified as a region having a contiguous set of pixels exceeding a preset reflectivity and size threshold. The high temporal resolution of the SACR 2-D observations (30 sec) allows for an area superposition criteria algorithm to match cloud elements at consecutive times. Following CITA, the temporal evolution of cloud element properties (number, size, and maximum reflectivity) is presented. The vast majority of the designated elements during this cumulus event were short-lived non-precipitating clouds having an apparent life cycle shorter than 15 minutes. The advantages and disadvantages of cloud tracking using an SACR are discussed.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
• OSTI ID: 1182525
• Report Number(s): BNL--107582-2015-JA; KP1701000
• Journal Information: Journal of Applied Meteorology and Climatology, Journal Name: Journal of Applied Meteorology and Climatology Journal Issue: 12 Vol. 53; ISSN 1558-8424
• Publisher: American Meteorological SocietyCopyright Statement
• Country of Publication: United States
• Language: English