Identification and Characterization of Persistent Cold Pool Events from Temperature and Wind Profilers in the Columbia River Basin

Journal Article · Mon Dec 30 00:00:00 EST 2019 · Journal of Applied Meteorology and Climatology

DOI:https://doi.org/10.1175/JAMC-D-19-0046.1· OSTI ID:1608784

McCaffrey, Katherine L. ^[1]; Wilczak, J. M. ^[2]; Bianco, L. ^[3]; Grimit, Eric ^[4]; Sharp, Justin ^[5]; Banta, Robert M. ^[6]; Friedrich, Katja ^[7]; Fernando, H ^[8]; Krishnamurthy, Raghavendra ^[9]; Leo, Laura ^[8]; Muradyan, Paytsar ^[10]

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1. NOAA
2. NOAA/ETL, Boulder, CO
3. University of Colorado
4. Project collaborator
5. Sharply Focused
6. NOAA Environmental Technology Laboratory
7. University of Colorado at Boulder
8. University of Notre Dame
9. BATTELLE (PACIFIC NW LAB)
10. ARGONNE NATL LAB

Cold pool events occur when deep layers of stable, cold air remain trapped in a valley or basin for multiple days, without mixing out from daytime heating. With large impacts on air quality, freezing events, and es-pecially on wind energy production, they are often poorly forecast by modern mesoscale numerical weather prediction (NWP) models. Understanding the characteristics of cold pools is, therefore, important to provide more accurate forecasts. This study analyzes cold pool characteristics with data collected during the Second Wind Forecast Improvement Project (WFIP2), which took place in the Columbia River basin and Gorge of Oregon and Washington from fall 2015 until spring 2017. A subset of the instrumentation included three microwave radiometer pro?lers, six radar wind pro?lers with radio acoustic sounding systems, and seven sodars, which together provided seven sites with collocated vertical pro?les of temperature, humidity, wind speed, and wind direction. Using these collocated observations, we developed a set of criteria to determine if a cold pool was present based on stability, wind speed, direction, and temporal continuity, and then developed an automated algorithm based on these criteria to identify all cold pool events over the 18 months of the ?eld project. Characteristics of these events are described, including statistics of the wind speed distributions and pro?les, stability conditions, cold pool depths, and descent rates of the cold pool top. The goal of this study is a better understanding of these characteristics and their processes to ultimately lead to improved physical parameterizations in NWP models, and consequently improve forecasts of cold pool events in the study region as well at other locations that experiences similar events.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1608784
• Report Number(s): PNNL-SA-150378
• Journal Information: Journal of Applied Meteorology and Climatology, Vol. 58, Issue 12
• Country of Publication: United States
• Language: English