Search Results

You are looking at 31 - 40 of 477 items for :

  • Planetary atmospheres x
  • Weather and Forecasting x
  • All content x
Clear All
Timothy J. Schmit, Wayne F. Feltz, W. Paul Menzel, James Jung, Andrew P. Noel, James N. Heil, James P. Nelson III, and Gary S. Wade

plus GOES retrievals A ground-based Atmospheric Emitted Radiance Interferometer (AERI; Revercomb et al. 1993 ) is also located at the SGP CART site facility; the AERI measures high spectral resolution infrared radiances emanating from the atmosphere above. These data, combined with collocated GOES data, were used to produce another set of retrievals. The GOES plus AERI retrievals produced additional improvements in TPW rms and bias over the GOES-only retrievals. Within the planetary boundary layer

Full access
Gary M. Lackmann and John R. Gyakum

moisture plumes may also extend to the surface. Despite the important socioeconomic impact of PE events, the authors are not aware of any previous studies that specifically examine the flow anomalies and moisture transport that accompany the PE events, or their linkage to subtropical moisture bursts. The first goal of this study is to document the planetary- and synoptic-scale flow patterns that typically accompany PE events. Identifiable PE precursors in the planetary-scale flow pattern could

Full access
Maria E. B. Frediani, Joshua P. Hacker, Emmanouil N. Anagnostou, and Thomas Hopson

1. Introduction This study analyzes near-surface (10 m) wind speeds of numerical simulations using criteria that elucidate the specific conditions determining the wind speed and wind component bias for damaging winds. Biases from different planetary boundary layer (PBL) schemes, conditioned on flow regime, topography, season, and diurnal cycle, inform model implementation decisions and forecaster guidance for the damage scale and impact areas. Motivated by a necessity for computationally

Full access
John S. Kain, Stephen M. Goss, and Michael E. Baldwin

subsequent hydrometeors to fall farther before melting completely. This effect promotes a gradual downward propagation of melting-induced cooling and, when temperature tendencies associated with other processes are relatively small, it can create an isothermal layer with a temperature of 0°C (e.g., Findeisen 1940 ). This characteristic isothermal layer does not always form when hydrometeors melt because in most precipitating atmospheres other processes mask the effect of melting. For example, cooling

Full access
Bartlett C. Hagemeyer and Gary K. Schmocker

develop, as well as potential mechanisms toinitiate intense convection, are crucial to severe-stormforecasting. Over the years, researchers such as Showalter and Fulks (1943), Fawbush and Miller (1952),Beebe ( 1958 and 1963), Darkow (1969), Wills (1969),Darkow and Fowler ( 1971 ), Lustig (1973), Maddox(1976), and Taylor and Darkow (1982) have usedmean upper-air sounding data to investigate the structure of the atmosphere in proximity to tornadic thunderstorms. Recent studies indicate renewed interest

Full access
Jing-Shan Hong

and compared them with the National Centers for Environmental Prediction (NCEP) Eta Model at 10-km resolution (Eta-10). Their MM5 simulation used the explicit moisture scheme of Hsie et al. (1984) , the Kain–Fritsch cumulus parameterization scheme, and the Zhang and Anthes (1982) planetary boundary scheme. They found the MM5 simulations needed 12–18 h to spin up the model precipitation owing to the cold start process (no hydrometeors at the beginning of the simulation), and the most skillful 6

Full access
David Siuta, Gregory West, and Roland Stull

the same area. In some cases the difference in estimated wind power density varied by several hundred watts per square meter, both seasonally and daily. Several studies have recently been done to evaluate the effects of WRF planetary boundary layer (PBL) physics parameterization scheme choice on wind forecasts. Shin and Hong (2011) evaluated five PBL schemes for a single-day case study in the CASES-99 dataset and found larger differences and higher biases in 10-m wind forecasts produced by

Full access
Mathieu Nuret and Michel Chong

MARCH 1996 NURET AND CHONG 53 Monitoring the Performance of the ECMWF Operational Analysis Using the Enhanced TOGA COARE Observational Network MATHIEU NURET AND MICHEL CHONG Centre National de Recherches Me-te-orologiques, Me-te-o-France and CNRS, Toulouse, France (Manuscript received 6 March 1995, in final form 2 October 1995) ABSTRACT An enhanced atmospheric monitoring effort has been set up during the Intensive Observation Period ( IOP) of the Coupled Ocean- Atmosphere

Full access
Masaru Kunii and Takemasa Miyoshi

intensification of TCs as the evaporation rate is enhanced by the increasing wind speed. The intensifying winds in turn enhance mixing in the upper ocean, contributing to cooling SSTs beneath the TCs ( Price 1981 ). Lowering SST then results in the reduction of sensible and latent heat fluxes into the atmosphere from the ocean surface and leads to a decrease in storm intensity ( Ginis 2002 ). These positive and negative feedback processes have nonlinear interactions and introduce complexities into the TC

Full access
Thomas L. Black

Mesinger(1984) in order to remove to a large extent the errorsthat are known to occur when computing the pressuregradien~t force, as well as the advection and horizontaldiffusion, along a steeply sloped coordinate surface.Like the sigma coordinate (Phillips 1957), eta is pressure based and normalized, which means that bothshare the mathematical advantages of casting the governing equations of the atmosphere into a relativelysimple form. The eta coordinate is defined by the relation ( P -- PT

Full access