Search Results

You are looking at 1 - 10 of 18 items for

  • Author or Editor: V. E. Suomi x
  • Refine by Access: All Content x
Clear All Modify Search
P. M. Kuhn and V. E. Suomi

Abstract

A conventional Eppley Pyrheliometer was converted into a beam reflector by mounting it, upright, in the prime focus of a parabolic mirror. This unit, attached to an aircraft, provides a means of obtaining reflected short-wave radiation from small areas such as fields, cities, lakes, etc. Results of albedo measurements over parts of South Dakota, Iowa, and Wisconsin are given.

Full access
D. N. Sikdar and V. E. Suomi

Abstract

In this paper we have used time-lapse ATS-I satellite cloud photographs as our data source for the evaluation of the convective transport of latent heat from the lower troposphere to the tropical upper troposphere.

The analysis reveals that the meso- to subsynoptic-scale convection systems over the tropical mid-Pacific are well organized on a time scale of a few days and are controlled by the large-scale motion field. The time variation of this beat transport, in the sector 12OW–18OW, 15N–15S, indicates an approximate periodicity of five days. Furthermore, this pulsating feature seems to be tied to a wave-like disturbance field of wavelength nearly 75° of longitude and moving westward with an approximate speed of 15° of longitude per day.

Full access
D. N. Sikdar and V. E. Suomi

Abstract

This paper develops an objective technique for estimating the mass and energy exchange in convection systems corresponding to altocumulus cumulogenitus and cumulonimbus intensities using measurements of the area change of the cirrus outflow on a sequence of satellite cloud photographs obtained at geostationary altitude. The data clearly show that: 1) the technique is able to isolate vigorous and moderate convection regimes on the geostationary satellite cloud photos; and 2) the model-estimated mass and energy are consistent with ground-based measurements such as those of Braham and Brown.

Full access
P. M. Kuhn and V. E. Suomi

Abstract

Thin layers of particulates or clouds in the high troposphere and lower stratosphere are generally not visible to an observer at the surface, even under the favorable viewing conditions at sunset. They are not easily detected by a television camera in a satellite from above. Yet these layers affect upwelling infrared flux.

A flight program, employing balloon-borne radiometers and a jet aircraft from which visual observations of particle layers were made, was conducted to measure the attenuating effects of these layers on upwelling. terrestrial flux. An estimate of the error such attenuation can cause in surface temperatures deduced from the upward flux measurement was then made. The balloon-borne radiometers were launched from a desert area of California. During the ascents the presence of cirrus or particle layers could not he visually or photographically detected from the surface. They were, however, detected by the radiometer during ascent and by observers in a jet aircraft.

The observations indicated an attenuation in upward infrared flux as a result of an observed particle layer beneath the higher balloon-home measurements. This attenuation could cause a 5.0C surface temperature estimate error. Several similar observations and calculations without observers aloft show the same result.

Full access
V. E. Suomi and T. H. Vonder Haar

Abstract

No abstract available.

Full access
Soon-Ung Park, D. N. Sikdar, and V. E. Suomi

Abstract

Nimbus 4 data (11.5-μm) channel and ATS 3 digitized data were analyzed for three days during April and May, 1970. Cloud-top temperature, as measured by the 11.5-μm channel of the satellite radiometer, shows a close negative correlation with cloud brightness measured by the ATS 3 satellite. This is especially true in well-developed cumulonimbus clouds.

An estimate of cloud heights corresponding to cloud-top temperature was obtained by using radiosonde data and radar images, and the relationships between the cloud thickness and brightness counts were derived for the cumulonimbus clouds.

Full access
G. L. Darkow, V. E. Suomi, and P. M. Kuhn

A tornado-forecast tool based on surface thermal patterns is presented. The procedures and results of an operational test of this forecast tool are presented. The results of this test are evaluated and suggestions made for using this additional simple tool in conjunction with existing tornado forecasting techniques.

Full access
D. N. Sikdar, J. A. Young, and V. E. Suomi

Abstract

Time series of areal cloud coverage over the central Pacific are studied to determine the large-scale variations of tropical disturbance activity for a four-month period in 1967. The persistent and fluctuating components are found to be more prevalent in regions of high and low mean cloudiness, respectively, with major longitudinal variations in activity most evident in the Southern Hemisphere. Normalized power spectra show that the transient activity occurring in the equatorial zone is dominated by shorter periods of about four days, while longer periods are dominant away from the equator. Coherency magnitudes and phases between different locations indicate that propagating cloud systems are most identifiable at lower frequencies in the Southern Hemisphere, and at somewhat higher frequencies in the Northern Hemisphere. Activity with periods in excess of five days consists largely of both westward and eastward propagation on the planetary wave scale. The shorter periods appear to consist of both synoptic-scale and planetary-scale modes, with westward propagation dominant near the equator.

Full access
P. M. KUHN, V. E. SUOMI, and G. L. DARKOW

Abstract

Results and conclusions drawn from 50 radiometer-sonde ascents over Wisconsin are presented. Atmospheric infrared radiation flux is separated into upward, downward, and net components. Radiation divergence and resulting cooling are computed. Seasonal averages of these direct observations are compared.

Full access
V. E. Suomi, J. A. Businger, and P. M. Kuhn

Abstract

No Abstract Available.

Full access