Search Results

You are looking at 1 - 7 of 7 items for

  • Author or Editor: Samuel Penn x
  • Refine by Access: Content accessible to me x
Clear All Modify Search
Samuel Penn

Abstract

For the first time detailed ozone measurements were obtained in a hurricane. An instrumented U-2 airplane was flown into hurricane Ginny on 22 October 1963 off the South Carolina coast. The hurricane core was over-flown at several altitudes and observations of ozone and the standard meteorological variables were obtained from 50 mb (67,000 ft) to 300 mb(30,000 ft). Supplemental temperature data were available below 700 mb from two dropsondes. From the above observations and by including some information about the mean thermal structure in a hurricane similar to Ginny, an ”eye“ sounding was constructed from sea level up to 50-mb level. Some nearby environmental data above 200 mb were available, and more distant observations were obtained from the coastal radiosondes and an ozonesonde released at Tallahassee.

Analysis of the data suggested that the warm core extended only up to 200 mb, cloud top height. Between 190 and 119 mb(tropopause height), horizontal gradients of ozone and temperature were poorly defined. Above the tropopause and up to 105 mb the region over the eye was warmer and considerably richer ozone. In the layer from 100 to 50 mb, the horizontal gradients again became very weak.

Full access
Samuel Penn

Abstract

Data from an instrumented U-2 aircraft, an ozonesonde and standard radiosondes provided detailed meteorological and ozone data on 2 October 1963 in the vicinity of the tropopause over a stretch of several hundred miles. These observations are used to describe the small-scale structure and motions of the tropopause in a region removed from the jet stream.

The tropopause surface appeared to have a wave-like structure which was identifiable over a 2-hr period as the wave moved with the winds at the tropopause level. Furthermore, descending motion of 1.5 cm per sec was computed on the stratospheric side of the more inclined portion of the tropopause, while on the tropospheric side the air maintained constant height.

Full access
Samuel Penn

Abstract

Temperature and ozone data obtained in hurricane Isbell on 14 October 1964 by an instrumented U-2 aircraft are used in conjunction with several radiosonde observations to reconstruct some features of the structure at tropopause level. The tropopause was inclined upwards toward the eye, with a slope of 1:200, except that the slope reached a plateau at a point over the wall clouds. In addition, it appeared that the horizontal variation of vertical motion was insignificant in the upper troposphere and lower stratosphere regions over the hurricane core. An unusual feature found in Isbell was a deep cloud-filled volume over the eye that extended from about 250 to 100 mb (the tropopause pressure).

Full access
Samuel Penn

An explanation is offered for a case of violent and prolonged non-frontal thunderstorms in New England. The thunderstorms occurred in the vicinity of an upper level trough. An analysis of the situation points to the development of marked divergence in the upper troposphere and convergence at middle levels. The resulting vertical motions acted to decrease the stability of the air mass. The increased divergence-convergence aloft resulted from an intensification of the ridge to the west and not from any deepening of the trough in the thunderstorm area.

Full access
SAMUEL PENN

Abstract

No Abstract Available.

Full access
Samuel Penn
and
Bruce Kunkel

Abstract

Twelve-hour predictions of the mixing ratio and the per cent change in mixing ratio for several pressure surfaces are generated by a trajectory procedure. Inter-level comparisons of the forecasts are made. The mixing ratio predictions are compared with simple persistence.

Statistical analyses, including use of spectral analysis, are used to examine inter-level relationships of the mixing ratio, and to reveal characteristics about the spatial and temporal variability of the mixing ratio.

Full access
Samuel Penn
,
Charles Pierce
, and
James K. McGuire

Some features of the squall line situation of June 9, 1953 and accompanying tornadoes in central and eastern Massachusetts are discussed. From radarscope photographs, it is pointed out (1) that the Worcester tornado and the Franklin-Wrentham tornado each occurred in the right-rear quadrant of a squall-line thunderstorm cell, and (2) that this relative position, with an associated tail or hook in the radar echo, is similar to that of the Illinois tornado of April 9, 1953. A tentative explanation is suggested for tornado formation in this position.

Full access