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Robert J. Conzemius and Evgeni Fedorovich

patterns that are at least qualitatively comparable with the patterns that are observed in the atmosphere east of the dryline. 2. Observational input data and numerical setup The studied case was the 22 May 2002 convection initiation experiment that took place over the Oklahoma and Texas Panhandles. Numerous CBL measurements were taken on that day using a variety of mobile and fixed ground-based instruments as well as lidar- and radar-equipped aircraft. The target of the measurements was a north

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Margaret A. LeMone, Fei Chen, Mukul Tewari, Jimy Dudhia, Bart Geerts, Qun Miao, Richard L. Coulter, and Robert L. Grossman

soil moisture profile and/or T s , using a uniform distribution with ranges of ±0.02 and ±0.01 K, respectively. We varied grid spacings for both the surface and atmosphere grid together and separately, ran simulations with and without the Knievel et al. (2007) filter to damp unresolved motions (<6Δx), and changed the domain depth for some runs. The grid points in the innermost domain varied from 226 × 226 for the 200-m runs to 101 × 101 for the remaining runs. Because input data were based on

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Monica Górska, Jordi Vilà-Guerau de Arellano, Margaret A. LeMone, and Chiel C. van Heerwaarden

1. Introduction Previous studies of the diurnal variability of carbon dioxide (CO 2 ) focus mainly on surface processes such as photosynthesis and respiration ( Verma et al. 1989 ; Kim and Verma 1990 ; Lloyd and Taylor 1994 ), rather than on the CO 2 exchange between the atmospheric boundary layer (ABL) and the free atmosphere during daytime. This last process is driven by energy generated within the boundary layer, primarily by buoyancy, and shear at the ABL top. Vilà-Guerau de Arellano et

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Steven E. Koch, Wayne Feltz, Frédéric Fabry, Mariusz Pagowski, Bart Geerts, Kristopher M. Bedka, David O. Miller, and James W. Wilson

to trigger deep convection ( Doviak and Ge 1984 ; Droegemeier and Wilhelmson 1985 ; Wilson and Schreiber 1986 ; Mueller and Carbone 1987 ; Karyampudi et al. 1995 ; Koch and Clark 1999 ). Density currents are primarily horizontal mass flows driven by their greater density relative to their environment. In a stratified atmosphere, a density current may generate a hydraulic jump (a bore), causing a sudden increase in the depth of the layer beneath the inversion ( Simpson 1987 ; Crook 1988

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Diane Strassberg, Margaret A. LeMone, Thomas T. Warner, and Joseph G. Alfieri

1. Introduction Numerous studies show that daytime fair-weather surface wind speeds predicted by numerical weather prediction (NWP) models tend to be slower than observed wind speeds. Applying five different planetary boundary layer (PBL) schemes in the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) to simulate the diurnal cycle of wind and temperature under weakly forced fair-weather conditions, Zhang and Zheng (2004

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Margaret A. LeMone, Fei Chen, Mukul Tewari, Jimy Dudhia, Bart Geerts, Qun Miao, Richard L. Coulter, and Robert L. Grossman

and Radiation Test bed (CART; Stokes and Schwartz 1994 ) and the four First International Satellite Land Surface Climatology Project (ISLSCP) Flux Experiment (FIFE; Sellers et al. 1992 ), and SGP-97 (more information is available online at http://hydrolab.arsusda.gov/sgp97/ ). In the mid-1990s, a group of scientists organized the Cooperative Atmosphere-Surface Exchange Study (CASES; LeMone et al. 2000 , Yates et al. 2001 ) to focus on land surface interaction in the Walnut River basin in

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S. B. Trier, F. Chen, K. W. Manning, M. A. LeMone, and C. A. Davis

on seasonal precipitation amounts (e.g., Koster et al. 2004a , b ; Ruiz-Barradas and Nigam 2005 ). In this paper, we use a three-dimensional atmospheric model coupled with different land surface models (LSMs) to examine relationships between the land surface, the planetary boundary layer (PBL), and precipitation. The PBL evolution is a potentially important linkage between soil moisture and precipitation because soil wetness has been observed to strongly impact the daytime moist static energy

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Margaret A. LeMone, Mukul Tewari, Fei Chen, Joseph G. Alfieri, and Dev Niyogi

data from the International H 2 O Project (IHOP_2002; Weckwerth et al. 2004 ; LeMone et al. 2007a ) and the 1997 Cooperative Atmosphere–Surface Exchange Study (CASES-97; LeMone et al. 2000 ). Here we focus on the more sparsely vegetated IHOP_2002 western track, located in the Oklahoma Panhandle. IHOP_2002 was organized to improve prediction of warm-season precipitation; the surface and boundary layer component looked at how surface processes affect the planetary boundary layer (PBL) and

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Edward I. Tollerud, Fernando Caracena, Steven E. Koch, Brian D. Jamison, R. Michael Hardesty, Brandi J. McCarty, Christoph Kiemle, Randall S. Collander, Diana L. Bartels, Steven Albers, Brent Shaw, Daniel L. Birkenheuer, and W. Alan Brewer

installation in the Falcon adjacent to the DLR DIAL system. DIAL is an appropriate technique for the remote sensing of atmospheric trace gases such as water vapor. A DIAL emits short light pulses into the atmosphere at two distinct wavelengths. The online wavelength is tuned to the center of a molecular water vapor absorption line (around 927 nm in IHOP_2002). The offline wavelength is the reference and contains information about the aerosol load and cloud cover of the probed atmosphere. Combining both

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