Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: H. L. CRUTCHER x
  • Refine by Access: All Content x
Clear All Modify Search
H. E. LANDSBERG, J. M. MITCHELL JR., and H. L. CRUTCHER

Abstract

Power spectrum techniques are applied to series of daily, weekly, and monthly average temperature and precipitation values, recorded since 1870 at the Woodstock Climatological Benchmark Station in Maryland, in order to gain a reasonable interpretation of the extent and frequency distribution of periodic variations in these data. Analysis procedures are outlined, and the results presented, interpreted, and collated with the results of earlier literature in some detail.

Apparent short-period variations are found whose periods lie near 3 days, between 5 and 7 days, and between about 15 and 25 days; various of them however, are absent from some portions of the data series and also differ somewhat in character with the season of the year.

Significant long-period variations are more prevalent in the temperature series than in the precipitation series. Spectral peaks in temperature, of periods near 2 years and greater than 50 years, both achieve high levels of statistical significance. The 11-year sunspot cycle, and to some extent its second harmonic as well, is suggested in the temperature data. The double (22-year) sunspot cycle and the longer Brückner cycle, however, are almost totally absent. The basis of Abbot's statistical long-range prediction scheme, which utilizes numerous higher harmonics of the double sunspot cycle, is tested against the Woodstock data, and is found in this caw to lack measurable skill above chance.

Full access
H. E. LANDSBERG, J. M. MITCHELL JR., and H. L. CRUTCHER

Abstract

No Abstract Available.

Full access
William H. Haggard, Thaddeus H. Bilton, and Harold L. Crutcher

Abstract

The results of a statistical study of maximum measured rainfall amounts of tropical cyclone systems whose paths cross the Appalachian Mountains an presented. The study includes storms from 1900 through 1969 and considers primarily the maximum recorded rainfall in mountainous terrain. The criteria are that the tropical cyclone had to pass the 1000-ft contour and that the precipitation was measured inside the outer-most 1000-ft contour. In some cases the maxima were recorded at altitudes below the 1000-ft contour; these locations were in valleys surrounded by higher elevations. Supplemental information is presented for maximum rainfall anywhere after storm landfall, although passage of the system over the Appalachian region remained a criterion.

The data are modelled by the gamma distribution. Probabilities of exceeding a specified rainfall amount and rainfall amounts for specified probability levels are presented in tabular and graphical form.

Full access
H. E. LANDSBERG, J. M. MITCHELL JR., H. L. CRUTCHER, and F. T. QUINLAN

Abstract

Further evidence is presented for the presence of a persistent periodicity somewhat in excess of 2 years duration. Its existence can be shown in the surface temperature at widely separated stations along two meridians from Norway to South Africa and from Canada to Cape Horn. Time series analysis by means of a narrow band-pass filter indicates phase relations among the stations, the most important of these being that the intertropical regions appear to be mutually in phase and that the higher-latitude stations are out of phase with the tropical stations. In the Northern Hemisphere, at extratropical stations, the amplitudes of the pulse are largest when the pulse extremes coincide with the winter months.

Full access