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Verner E. Suomi and William C. Siien

Abstract

According to radiometersonde observations, the net vertical flux divergence of infrared radiation is positively correlated with the outward flux at the top of the atmosphere. Measurements of the latter quantity from the Explorer VII satellite are shown to he correlated with tropospheric temperature, such that warm air on the average is cooled less than cold air at the same latitude by infrared radiation. Calculations of the generation of eddy available potential energy by this process are presented and shown to be significant.

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Sanjay Shridhar Limaye and Verner E. Suomi

Abstract

We present results on cloud motions on Venus obtained over a period of 3.5 days from Mariner 10 television images. The implied atmosphere flow is almost zonal everywhere on the visible disk, and is in the same retrograde sense as the solid planet. Objective analysis of motions suggests presence of jet cores (−130 m s−1) and organized atmospheric waves. The longitudinal mean meridional profile of the zonal component of motion of the ultraviolet features shows presence of a midlatitude jet stream (−110 m s−1). The mean zonal component is −97 m s−1 at the equator. The mean meridional motion at most latitudes is directed toward the pole in either hemisphere and is at least an order of magnitude smaller so that the flow is nearly zonal. A tentative conclusion from the limited coverage available from Mariner 10 is that at the level of ultraviolet features mean meridional circulation is the dominant mode of poleward angular momentum transfer as opposed to the eddy circulation.

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Thomas H. Vonder Haar and Verner E. Suomi

Abstract

This paper summarizes an extended time series of measurements of the earth's radiation budget from the first and second generation United States meteorological satellites. Values of planetary albedo, infrared radiant emittance, and the resulting net radiation budget are now available for 39 months during the period 1962–66. These measurements show a mean global albedo of 30%, and net radiation balance within measurement accuracy. The discussion treats global and zonally averaged values for the “mean annual” case, for “mean seasons,” and includes a comparison of measurements during the same seasons in different years. The role of these radiation budget measurements in the total global energy balance is noted.

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MELVIN WEINSTEIN and VERNER E. SUOMI

Abstract

Long-wave radiation loss maps, based on Explorer VII measurements of terrestrial radiation at night, are analyzed and compared with composite nephanalyses and frontal analyses. Results indicate a definite relationship between the radiation centers and their corresponding surface low and high pressure centers, their locations, 24-hour intensifications and movements, and the conformity of these movements to the 500-mb. geostrophic flow. Some of the potential applications to analysis and forecasting are noted.

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Earl W. Barrett and Verner E. Suomi

Abstract

Following a brief review of the assumptions involved in the usual (Laplacian) expression for the speed of sound waves, an instrument, the sonic thermometer, is described which utilizes this relationship to measure the air temperature. The advantages of the sonic thermometer are then discussed, the main advantages being the absence of radiational errors and extremely low lag—a result of the fact that the measured variable, the speed of sound, is independent of the properties of the measuring elements.

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Nadav Levanon, Juris Afanasjevs, Robert A. Oehlkers, and Verner E. Suomi

Abstract

The pressure sensor for the Tropical Wind Energy conversion and Reference Level Experiment (TWERLE) is described. Key design features of the sensor are: capacitive coupling, reference at midrange, up-down counting, passive oven, storage at flight pressure and prelaunch calibration. Sensor specifications are given which are based on the production results of 440 units. Drift, as estimated from simulated life tests, is 1 mb per 6 months. The overall weight of the sensor, including thermal package, is 180 g.

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Verner E. Suomi, Kirby J. Hanson, and Robert J. Parent

Abstract

This paper reports on a digital measurement (“chirp”) system which has application for a wide range of meteorological and earth satellite measurements.

The system employs a simple concept in which a voltage pulse, proportional to a sensor voltage, is used to generate a burst of pulses from a voltage controlled oscillator (VCO). A count of the high frequency oscillations which make up the “chirp” provides the digital measurement. The system is adapted to multiple sensor use with a multiplexer.

The system has the advantage in that one has the option of selecting an ac amplifier for low level signals in conjunction with a variety of multiplexers and VCO for the desired measurement. One particular combination of multiplexer and VCO was used to demonstrate its use as a digital radiosonde.

A flight test of the digital radiosonde was obtained. Results clearly show fine structural detail in the temperature profile without any need for subjective interpretation by the operator. Numerous isothermal and inversion layers less than 100 m in thickness were observed.

The digital radiosonde used conventional (U.S. Weather Bureau) temperature and humidity sensors. Temperature resolution is about 0.1C and relative humidity is about 0.1 per cent. The system resolution is 0.1 per cent.

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Stephen K. Cox, James A. Maynard, and Verner E. Suomi

Abstract

An analysis of tropical radiosonde temperature measurements made during the Line Island Experiment suggests that conventional radiosonde preflight procedures are inadequate in a remote tropical environment. Temperatures computed from conventional and modified baseline techniques are compared at five pressure surfaces, 1000, 800, 600, 400 and 200 mb. Temperatures obtained from the two baseline techniques showed an average deviation at 1000 mb of 0.96C for 62 soundings. These comparisons indicate that a careful examination of radiosonde calibration techniques is needed before large investments are made in future global experiments.

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KIRBY J. HANSON, THOMAS H. VONDER HAAR, and VERNER E. SUOMI

Abstract

This study describes a method for determining the reflection of sunlight to space and absorption by the earth and atmosphere, using low-resolution radiometer data from earth satellites. The method has been used with TIROS IV data together with radiation measurements at the ground to determine the reflection and absorption of sunlight over the United States during the spring of 1962.

The results indicate that for this region and time, 40 percent of the incident sunlight at the top of the atmosphere was reflected to space, 13 percent was absorbed by the atmosphere and clouds, and the remaining 47 percent was absorbed at the earth's surface. Atmospheric absorption of sunlight varied from over 20 percent in the moist air in southeastern United States to less than 10 percent over much of the dry mountainous west and northern plains.

When atmospheric absorption values determined from this study are compared with earlier studies of absorption in a cloudless atmosphere, there is good agreement at low values of atmospheric water vapor; however, the present study gives significantly higher absorption at high values of water vapor.

Based on this study, an empirical relationship is determined for fractional absorption of sunlight in an atmosphere with clouds as a function of optical pathlength of water vapor: qa=0.096+0.045(u*)½logeu*. The fractional absorption of sunlight, qa, is the fraction of the total amount incident at the top of the atmosphere. The optical pathlength, u*, is given in cm.: u*=u.sec ζ. Here, u is total precipitable water in a vertical column, given in cm., and ζ is the solar zenith angle.

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Nadav Levanon, Robert A. Oehlkers, Scott D. Ellington, William J. Massman, and Verner E. Suomi

Abstract

This paper presents measured data related to the question of how constant are “constant-level” balloons. The simultaneous use of two balloon-borne instruments, a radio altimeter and a pressure sensor, operating on entirely different principles, help to distinguish between sensor noise and true balloon altitude fluctuation. Four types of superpressure balloon altitude changes at the level of 150 mb were observed: (i) neutral buoyancy oscillations (NBO) with a period of about 200 sec and with peak-to-peak amplitude of up to 50 m, (ii) short-term oscillations with a period of ∼1.2 hr and peak-to-peak amplitudes of up to 80 m, (iii) diurnal half-cycle (day observations only) with an amplitude of up to 150 m, and (iv) possible trends of up to 120 m per day.

The data were obtained during four superpressure-balloon 150-mb flights in the Southern Hemisphere. These balloon flights were part of a test program for the TWERL Experiment. NCAR's GHOST balloons and navigation system were used, with the final version of the TWERLE radio altimeter and an early version of the pressure sensor.

The data are presented with a discussion of their limitations, mainly aliasing, ambiguity, and the absolute accuracy of the pressure sensor. A theoretical analysis of the NBO, with a spectrum analysis of supporting ground radar data, are given in the Appendix.

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