Search Results

You are looking at 1 - 3 of 3 items for :

  • Author or Editor: Carl W. Kreitzberg x
  • Journal of Applied Meteorology and Climatology x
  • Refine by Access: Content accessible to me x
Clear All Modify Search
Carl W. Kreitzberg

Abstract

Supersonic transport (SST) fuel consumption is very sensitive to ambient temperatures in the region of climb from 25,000 to 52,000 ft within 200 n mi and 20 min of takeoff. It has been suggested in the literature that extensive sounding networks may be required to provide adequate temperature forecasts for SST operations.

The thermal wind relation implies that the mean temperature in this deep layer will not change rapidly in space or time and that wind shears can be used as predictors of the changes. An empirical study using the Project Stormy Spring mesoscale rawinsonde network data confirms the thermal wind implication that these mesoscale temperature changes are small. Only 6-hr soundings at a single site near the airport are required for reasonably efficient SST operation. However, predictions based on wind shear explain only about 20% of the variance of the observed temperature changes.

Full access
Carl W. Kreitzberg

Abstract

Data from a 10-site mesoscale rawinsonde network are used to document a number of features in the wind field in a mature cyclone of moderate intensity. The general nature of, and some particular phenomena in, the mesoscale wind field are discussed. Fields of divergence and vertical velocity are presented and the ageostrophic nature of the wind shear is demonstrated.

Specific features examined include mid-tropospheric oscillations in wind direction, a low-level jet stream, the coincidence of the tropopause with an ageostrophic level of maximum wind, and the jet-front shear zone.

In view of these results from AFCRL's project Stormy Spring, some of the capabilities and limitations of mesoscale rawinsonde data are discussed.

Full access
Carl W. Kreitzberg and H. Albert Brown

Abstract

Precipitation systems within a mature extratropical cyclone are related to the mesoscale thermal and circulation fields aloft using data from Project Stormy Spring conducted by the Air Force Cambridge Research Laboratories. Precipitation systems were analyzed using radars and recording raingages, including a special mesoscale array; upper-air structures were deduced from a 10-site mesoscale rawinsonde network including serial soundings at 90-min intervals.

Results show that most of the widespread precipitation, in conjunction with the cyclonic-scale vertical motions in frontal baroclinic zones, occurs in bands and groups of showers. A sub-synoptic core of cold dry air in the middle troposphere ahead of the surface occlusion was found to be subsiding and surpressing wide-spread cloudiness, while it was furnishing a large amount of potential instability. The cyclone-scale ascending motions then released the potential instability around this cold core and also above the warm frontal stable layer. The convection became aligned in bands roughly parallel to the wind shear in the convective layer. These bands included clusters of cells of more intense precipitation.

The cyclonic-scale baroclinic zone associated with the synoptic fronts is made up of multiple mesoscale hyper-baroclinic zones which are shown to be related to the existence and production of potential instability and to precipitation bands and groups of cells.

Full access