Search Results
You are looking at 1 - 4 of 4 items for
- Author or Editor: MARY W. HODGE x
- Refine by Access: All Content x
Abstract
The assumption that a rawinsonde balloon system may experience large changes in its rate of ascent, as compared to the average rate for the observation, while traversing a region of clear air turbulence is investigated. In a 5-day period a well-defined region of turbulence, concentrated near a trough, progressed eastward for several successive synoptic observations. Rawinsonde ascensional rates are studied for 20 stations located within and outside this turbulent region for layers 2,000 ft. to 2,500 ft. thick between about 20,000 ft. and 45,000 ft. in altitude. Those rawinsonde observations within the turbulent region show much larger ascensional rate changes between layers, compared to the average for the observation, than do those outside the turbulent region. Furthermore the observations showing these large variations progress eastward with time corresponding generally to the eastward motion of the turbulent region.
A large change or variation is defined as one for which the change in ascensional rates between adjacent layers is 25 percent or greater of the average ascensional rate for the observation. This value is about 2.5 times the standard deviation for the total population of these changes, about 2,100 observations, and about four times the estimated standard deviation of the errors involved in the pertinent rawinsonde observations.
This study is being extended to cover a larger portion of the United States for special clear air turbulence collection periods. If a relationship between clear air turbulence and large ascensional rate variations is established, it may be possible to use these data on a real time basis to detect and track clear air turbulence.
Abstract
The assumption that a rawinsonde balloon system may experience large changes in its rate of ascent, as compared to the average rate for the observation, while traversing a region of clear air turbulence is investigated. In a 5-day period a well-defined region of turbulence, concentrated near a trough, progressed eastward for several successive synoptic observations. Rawinsonde ascensional rates are studied for 20 stations located within and outside this turbulent region for layers 2,000 ft. to 2,500 ft. thick between about 20,000 ft. and 45,000 ft. in altitude. Those rawinsonde observations within the turbulent region show much larger ascensional rate changes between layers, compared to the average for the observation, than do those outside the turbulent region. Furthermore the observations showing these large variations progress eastward with time corresponding generally to the eastward motion of the turbulent region.
A large change or variation is defined as one for which the change in ascensional rates between adjacent layers is 25 percent or greater of the average ascensional rate for the observation. This value is about 2.5 times the standard deviation for the total population of these changes, about 2,100 observations, and about four times the estimated standard deviation of the errors involved in the pertinent rawinsonde observations.
This study is being extended to cover a larger portion of the United States for special clear air turbulence collection periods. If a relationship between clear air turbulence and large ascensional rate variations is established, it may be possible to use these data on a real time basis to detect and track clear air turbulence.
Abstract
Some instances of superadiabatic lapse rates in temperature observed in radiosonde observations may be produced or accelerated by adiabatic lifting. Examples are shown which suggest this possibility.
Abstract
Some instances of superadiabatic lapse rates in temperature observed in radiosonde observations may be produced or accelerated by adiabatic lifting. Examples are shown which suggest this possibility.
Abstract
Comparative data are reported from a group of twin or dual radiosonde observations made with U.S. Weather Bureau and military 1680me./sec. radiosondes. To compare the instruments directly, differences in temperature, pressure, and relative humidity are studied at simultaneous time marks during the observations. Root-mean-square differences of pressure, temperature, and relative humidity for each observation are summarized in table form. The root-mean-square differences for all observations combined are 2.1 mb. and 0.51° C.
Tables show temperature and height differences evaluated at constant pressure surfaces. These temperature differences are somewhat greater than those at simultaneous time marks, as would be expected with the permitted tolerances and the judgment required in placing levels. Moreover, temperature differences obtained by this method are modified by pressure differences.
Both types of radiosondes give compatible measurements, at least to the levels reached.
The radiosondes were obtained from field stock, were not changed or adjusted in the laboratory, and were flown in the same manner as for routine soundings except for the dual feature. Certain laboratory tests were conducted and factory calibration data were obtained from these radiosondes. These tests and data are reported but were not used in the evaluations of the observations.
Abstract
Comparative data are reported from a group of twin or dual radiosonde observations made with U.S. Weather Bureau and military 1680me./sec. radiosondes. To compare the instruments directly, differences in temperature, pressure, and relative humidity are studied at simultaneous time marks during the observations. Root-mean-square differences of pressure, temperature, and relative humidity for each observation are summarized in table form. The root-mean-square differences for all observations combined are 2.1 mb. and 0.51° C.
Tables show temperature and height differences evaluated at constant pressure surfaces. These temperature differences are somewhat greater than those at simultaneous time marks, as would be expected with the permitted tolerances and the judgment required in placing levels. Moreover, temperature differences obtained by this method are modified by pressure differences.
Both types of radiosondes give compatible measurements, at least to the levels reached.
The radiosondes were obtained from field stock, were not changed or adjusted in the laboratory, and were flown in the same manner as for routine soundings except for the dual feature. Certain laboratory tests were conducted and factory calibration data were obtained from these radiosondes. These tests and data are reported but were not used in the evaluations of the observations.
