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Publications:
Conference presentations:
Friedrich, K., F. Masters, J. Wurman, and D. Burgess 2010: Microphysical characteristics in supercell thunderstorms using mobile dual-polarization radars and mobile disdrometer. Conf. on Severe Local Storms, October 2010, Denver, CO.
Friedrich, K., J. Wurman, D. Burgess, and F. Masters 2010: Microphysical characteristics in supercell thunderstorms using mobile dual-polarization radars and mobile disdrometer. 6th European Conference on Radar in Meteorology and Hydrology, September 2010, Sibiu, Romania.
Wurman, J., K. Friedrich, and K. Kosiba: Intercomparison of disdrometer and dual-polarization radar measurements in tornadic and non-tornadic supercells during VORTEX2. The Meeting of the Americas. August 2010, Foz do Iguassu, Brazil.
Friedrich, K.: Radar and disdrometer measurements during VORTEX2. Seminar at ATOC University of Colorado. April 2010, Boulder. CO
Friedrich, K., R. Humphrey, J. Wurman, and K. Kosiba: Study of microphysical and thermodynamic structures within supercell thunderstorms. 5th European Conference on Severe Storms, 12-16 October 2009, Landshut, Germany.
Friedrich, K., R. Humphrey, J. Wurman, and K. Kosiba: Study of microphysical and thermodynamic structures
within supercell thunderstorms. Conf. on Mesoscale Meteorology, Americ. Meteorol. Soc., August 2009, Salt Lake City, USA.
Reviewed publication in preparation:
Friedrich, K., F. Masters, G. Romine, and T. Schurr: Mobile disdrometer measurements during VORTEX2. (to be submitted in December 2010)
Objectives:
During VORTEX2 conducted in May-June 2009 and 2010 in the Great Plains we deployed eight mobile disdrometers measuring distribution of drop sizes and fall velocity and surface observation stations (Images on the left) in the path of supercell thunderstorms. Measurements were coordinated with VORTEX2 instrumentation in particular the mobile X-band radars (Image below) – enabling fusion of data sources for a more complete retrieval of the near surface buoyancy field, kinematic and microphysical structures of supercell thunderstorms. This effort marks a first known attempt to collect in-situ near surface measurements of particle size distributions (PSD) by a network of disdrometers owing to the considerable challenges and hazards associated data acquisition within severe storms owing to the considerable challenges and hazards associated data acquisition within severe storms. The collected observations will enable new understanding of the relationship between microphysical characteristics of severe storms and their behavior in line with several key foci within the Vortex2 science objectives.
Disdrometer Team:
Stephanie Higgins Danielle Nuding Evan Kalina James Rudolph
U. of Colorado (Geology) U. of Colorado (ATOC) U. of Colorado (ATOC) U. of Colorado (ATOC)
Carlos Lopez George Fernandez Scott Landolt Cameron Redwine Katja Friedrich
U. of Florida U. of Florida NCAR Metro State U. of Colorado (ATOC)
What do we do with the disdrometers in a supercell thunderstorm?
The objective of a mobile deployment is to observe temporal and spatial variations of drop-size distributions by transecting the same storm several times close to the VORTEX2 radar facilities. To achieve this goal, disdrometers will be placed several minutes ahead of the thunderstorms relative to their translation direction while the thunderstorms pass over the instruments. For fast-moving storms (>30 knots), the fixed laser disdrometer teams will deploy using a picket fence strategy perpendicular to the storm motion in advance of approaching storms (Figure below, left panel). For slow-moving storms (< 30 knots), the disdrometers will be relatively closely spaced (0.5-1 km) and deployed in order to sample the connecting region between the hook appendage and the storm core (Figure below, right panel). The mobile disdrometer will focus on northeast-southwest transects through the hook appendage, where practical, both just north and just south of the low-level mesocyclone, with the expectation of data collection during westbound transects only (eastbound transects may often lack adequate probe-relative winds for useful measurements). Fixed site deployment lines aligned with the storm motion will also be considered on a case-by-case basis (as road networks and storm motion allows) to sample hook appendage PSD temporal evolution characteristics shown). After the storm passes over the instruments, the mobile disdrometers will be relocated again ahead of the storm, parked, and measurements will be repeated. The NSSL instruments will operate in an unmanned mode, i.e., the instruments will be placed outside the mobile mesonet vehicles. The CU instruments will operate in an unmanned deployment mode during slow-moving storms and truck deployment mode during fast-moving storms.
Figure: Idealized deployment of mobile disdrometers during the VORTEX 2010 for a) fast-moving and b) slow-moving storms. Disdrometers are indicated as red arrows with the idealized transects indicated as red dashed lines. Four disdrometers will be deployed as part of this proposal and two instruments will be provided by the NSSL.The road network is indicated with gray dashed lines.
CU disdrometer in the news:
Daily Camera: Boulder Scientists prepare for six-week tornado chase
Channel 4 Denver:
Scientific America: Twister Mysteries Lure Scientists to Launch Massive Midwest Field Experiment
Tornado Surrounded by Instruments as Scientists Aim to Catch Their “Perfect Storm”
Aricles & Interviews about VORTEX2:NSF press release, Daily Camera, Washington Post, Der Standard, The
Takeaway, Deutschlandfunk