1,722,336 research outputs found
Differences between Nonprecipitating Tropical and Trade Wind Marine Shallow Cumuli
No full textMarine nonprecipitating cumulus topped boundary layers (CTBL) observed in a tropical and in a trade-wind region are contrasted based on their cloud macro-physical, dynamical, and radiative structures. Data from the Atmospheric Radiation Measurement (ARM) observational site previously operating at Manus Island and data collected during the deployment of ARM Mobile Facility at the island of Graciosa were used in this study. The tropical marine CTBL were deeper, had higher surface fluxes and boundary layer radiative cooling, but lower wind speeds compared to their trade-wind counterparts. The radiative velocity scale was 50-70% of the surface convective velocity scale at both locations, highlighting the prominent role played by radiation in maintaining turbulence in marine CTBLs. Despite greater thicknesses, the chord lengths of tropical cumuli were on average lower than that of trade wind cumuli, and due to lower cloud cover, the hourly averaged (cloudy and clear) liquid water paths of tropical cumuli were lower than the trade-wind cumuli. At both locations ~70% of the cloudy profiles were updrafts, while the averaged amount of updrafts near cloud base stronger than 1 m s-1 was ~22% in tropical cumuli and ~12% in the trade-wind cumuli. The mean in-cloud radar reflectivity within updrafts and mean updraft velocity was higher in tropical cumuli than the trade-wind cumuli. Despite stronger vertical velocities and more amount of strong updrafts, due to lower cloud fraction, the updraft mass-flux was lower in tropical cumuli compared to the trade-wind cumuli. The observations suggest the tropical and trade-wind marine cumulus clouds to differ significantly in their macro-physical and dynamical structures.Peer reviewe
Matthews, Robert
No full textOral History interview of Robert Matthews. Interview conducted by Miller, Mark at NAWCTSD, Orlando, FL
Mohler, Richard Andrew interview
No full textOral History interview of Richard Mohler. Interview conducted by Miller, Mark at Orlando, FL
A one-year study of the diurnal cycle of meteorology, clouds and radiation in the West African Sahel region
No full textThe diurnal cycles of meteorological and radiation variables are analysed during the wet and dry seasons over the Sahel region of West Africa during 2006 using surface data collected by the Atmospheric Radiation Measurement (ARM) programme’s Mobile Facility, satellite radiation measurements from the Geostationary Earth Radiation Budget (GERB) instrument aboard Meteosat 8, and reanalysis products from the National Centers for Environmental Prediction (NCEP). The meteorological analysis builds upon past studies of the diurnal cycle in the region by incorporating diurnal cycles of lower tropospheric wind profiles, thermodynamic profiles, integrated water vapour and liquid water measurements, and cloud radar measurements of frequency and location. These meteorological measurements are complemented by 3 h measurements of the diurnal cycles of the top-of-atmosphere (TOA) and surface short-wave (SW) and long-wave (LW) radiative fluxes and cloud radiative effects (CREs), and the atmospheric radiative flux divergence (RFD) and atmospheric CREs. Cirrus cloudiness during the dry season is shown to peak in coverage in the afternoon, while convective clouds during the wet season are shown to peak near dawn and have an afternoon minimum related to the rise of the lifting condensation level into the Saharan Air Layer. The LW and SW RFDs and CREs exhibit diurnal cycles during both seasons, but there is a relatively small difference in the LW cycles during the two seasons (10 − 30Wm−2 depending on the variable and time of day). Small differences in the TOA CREs during the two seasons are overwhelmed by large differences in the surface SW CREs, which exceed 100Wm−2. A significant surface SW CRE during the wet season combined with a negligible TOA SW CRE produces a diurnal cycle in the atmospheric CRE that is modulated primarily by the SW surface CRE, peaks at midday at ∼ 150Wm−2, and varies widely from day to day.Peer reviewe
Phillips, Michael interview
No full textOral History interview of Michael Phillips. Interview conducted by Miller, Mark at Mr. Phillips\u27 home in Orlando, FL
Wohl, Thomas Maclyn interview
No full textOral History interview of Thomas Wohl. Interview conducted by Miller, Mark; Wohl, Linsy at Mr. Wohl\u27s Home
Francis, Dewitt T. interview
No full textOral History interview of Dewitt Francis. Interview conducted by Miller, Mark and Hazen, Kendra at Veterans Residence
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