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  • Boundary conditions x
  • Understanding Diurnal Variability of Precipitation through Observations and Models (UDVPOM) x
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R. Cifelli, S. W. Nesbitt, S. A. Rutledge, W. A. Petersen, and S. Yuter

-scale organization of precipitation across the domain (i.e., MCSs did not occur) were defined as sub-MCS-only (SMO) conditions. These periods were identified using time series of 6-h averaged wind speed and feature size (see Figs. 2 and 3 ). As expected, these time intervals generally contained a relatively high fraction of sub-MCS features and low rain rates. SMO conditions were rare during EPIC compared to TEPPS (see Table 1 ). Moreover, two of the EPIC SMO periods (Julian dates 256–258 and 264

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J. Li, S. Sorooshian, W. Higgins, X. Gao, B. Imam, and K. Hsu

model ( Chen and Dudhia 2001 ). The vertical coordinate of MM5 is a terrain-following coordinate system. In this study, 31 vertical sigma layers were employed from the surface to the top of atmosphere at 100 mb. The operational NCEP Eta Model 212 grid (40 km) model analysis data for July and August 2004 were used as forcing fields. The Eta Model analysis data were used as model initial conditions and model boundary conditions in all tests. The model was initialized at 0000 UTC and integrated up to

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T. N. Krishnamurti, C. Gnanaseelan, A. K. Mishra, and A. Chakraborty

parameterization schemes are used to construct multimodel ensemble forecasts with the T170 FSUGSM. Five-day-long forecasts were carried out with all six versions of the model starting at 1200 UTC 1 May 2001 and continuing until 1200 UTC 31 August 2001. Initial conditions were extracted from the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40). Sea surface temperature (SST) boundary conditions were obtained from the Reynolds and Smith (1994) weekly datasets and

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R. E. Carbone and J. D. Tuttle

The semidiurnal maximum east of 92°W may be the result of one or more influences, including Gulf of Mexico breezes. To isolate these breeze effects, we repositioned the domain’s southern boundary northward from 30° to 33°N ( Fig. 6 ). This domain change reduces both the diurnal and semidiurnal amplitudes resulting from the exclusion of the Gulf Coast region. A weak semidiurnal signal is still apparent in approximately one-half of the 36-monthly averages. It was most prevalent in 1997 and 2000, and

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Alex C. Ruane and John O. Roads

troposphere generally have the greatest influence on the water cycle. The E is a function of the atmospheric boundary layer’s thermodynamic influence on evaporative parameterizations, and is therefore strongly affected by radiative forcings (see, e.g., RR07a ). The P is heavily parameterized in the R2, and is therefore dominated by the triggering mechanisms and dynamic algorithms hard-wired into the SAS convection scheme, although boundary layer and other parameterizations also feed into the

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Donald Wylie

analyses with more frequent observations. Significant diurnal cycles were found over landmasses mainly in the summer season, which appear to be driven by solar heating of the land surface. The highest values in cloud cover were usually found just after solar noon from the increase in boundary layer cumulus. Very large diurnal cycles were found in mountainous regions because of cumulus growth on south facing slopes inclined toward the sun. Upper-tropospheric cirrus clouds also show diurnal cycles in the

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Arindam Chakraborty and T. N. Krishnamurti

: where P is pressure of the layer and P s is surface pressure. In addition to that, in the nonconvective planetary boundary layer, the maximum relative humidity threshold is set to 0.90. Cloud fraction in a layer is derived from the mass-weighted relative humidity in that layer using Eq. (1) , where the threshold relative humidity RH c is derived from Eq. (4) . All of these schemes used large-scale parameters such as relative humidity, pressure, vertical stability, and CAPE to calculate cloud

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Song Yang, Kwo-Sen Kuo, and Eric A. Smith

is also a counterpart MLA secondary peak in the oceanic diurnal precipitation cycle (e.g., McGarry and Reed 1978 ; Reed and Jaffe 1981 ; Augustine 1984 ; Fu et al. 1990 ; Serra and McPhaden 2004 ), for which the only plausible explanation that can be put forward is an “ocean surface heating” (OSH) mechanism, which involves near-surface ocean, sea, and inland lake layers and moist boundary layers over water. However, there is yet to be an investigation of the secondary diurnal mode of

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Song Yang and Eric A. Smith

6 (v6) TRMM rain products are taken from three standard level 2 algorithms: 2a12, 2a25, and 2b31. The 2a25 and 2b31 surface rain rates are the estimated rain rates near surface. The 2a12 algorithm consists of a TMI-only microphysical profile scheme cast in Bayesian form, which uses a cloud resolving model (CRM) to generate numerous microphysical profiles of liquid and frozen hydrometeors for rainfall (R) conditions as a solution basis, in which solutions arise by combining microphysical profiles

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