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Sean M. Waugh, Conrad L. Ziegler, Donald R. MacGorman, Sherman E. Fredrickson, Doug W. Kennedy, and W. David Rust

Abstract

A balloonborne instrument known as the Particle Size, Image, and Velocity (PASIV) probe has been developed at the National Severe Storms Laboratory to provide in situ microphysical measurements in storms. These observations represent a critical need of microphysics observations for use in lightning studies, cloud microphysics simulations, and dual-polarization radar validation. The instrument weighs approximately 2.72 kg and consists of a high-definition (HD) video camera, a camera viewing chamber, and a modified Particle Size and Velocity (Parsivel) laser disdrometer mounted above the camera viewing chamber. Precipitation particles fall through the Parsivel sampling area and then into the camera viewing chamber, effectively allowing both devices to sample the same particles. The data are collected on board for analysis after retrieval. Taken together, these two instruments are capable of providing a vertical profile of the size, shape, velocity, orientation, and composition of particles along the balloon path within severe weather.

The PASIV probe has been deployed across several types of weather environments, including thunderstorms, supercells, and winter storms. Initial results from two cases in the Deep Convective Clouds and Chemistry Experiment are shown that demonstrate the ability of the instrument to obtain high-spatiotemporal- resolution observations of the particle size distributions within convection.

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N. L. Miller, A. W. King, M. A. Miller, E. P. Springer, M. L. Wesely, K. E. Bashford, M. E. Conrad, K. Costigan, P. N. Foster, H. K. Gibbs, J. Jin, J. Klazura, B. M. Lesht, M. V. Machavaram, F. Pan, J. Song, D. Troyan, and R. A. Washington-Allen

A Department of Energy (DOE) multilaboratory Water Cycle Pilot Study (WCPS) investigated components of the local water budget at the Walnut River watershed in Kansas to study the relative importance of various processes and to determine the feasibility of observational water budget closure. An extensive database of local meteorological time series and land surface characteristics was compiled. Numerical simulations of water budget components were generated and, to the extent possible, validated for three nested domains within the Southern Great Plains—the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Cloud Atmospheric Radiation Testbed (CART), the Walnut River watershed (WRW), and the Whitewater watershed (WW), in Kansas.

A 2-month intensive observation period (IOP) was conducted to gather extensive observations relevant to specific details of the water budget, including finescale precipitation, streamflow, and soil moisture measurements that were not made routinely by other programs. Event and seasonal water isotope (d18O, dD) sampling in rainwater, streams, soils, lakes, and wells provided a means of tracing sources and sinks within and external to the WW, WRW, and the ARM CART domains. The WCPS measured changes in the leaf area index for several vegetation types, deep groundwater variations at two wells, and meteorological variables at a number of sites in the WRW. Additional activities of the WCPS include code development toward a regional climate model that includes water isotope processes, soil moisture transect measurements, and water-level measurements in groundwater wells.

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