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Markus, M. J.

Publications and source records attributed to Markus, M. J..

4 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Detection of severe Midwest thunderstorms using geosynchronous satellite data

In the present exploration of the effectiveness of severe thunderstorm detection in the Midwestern region of the U.S. by means of approximately 5-min interval geosynchronous satellite data, thunderstorms are defined in IR data as points of relative minimum in brightness temperature T(B) having good time continuity and exhibiting a period of rapid growth. The four parameters of rate of T(B) decrease in the upper troposphere and stratosphere, isotherm expansion, and storm lifetime minimum T(B), are shown to be statistically related to the occurrence of severe weather on four case study days and are combined into a Thunderstorm Index which varies among values from 1 to 9. Storms rating higher than 6 have a much higher probability of severe weather reports, yielding a warning time lead of 15 min for hail and 30 min for the first tornado report.

Adler, R. F.↗
NASA NTRS1983

Thunderstorm top structure observed by aircraft overflights with an infrared radiometer

Thunderstorm top structure is examined with high spatial resolution radiometric data (visible and infrared) from aircraft overflights together with other storm views, including geosynchronous satellite observations. Results show that overshooting cumuliform towers appear as distinct cold areas in the high resolution, 11-micron IR aircraft images, but that the geosynchronous satellite observations significantly overestimate the thunderstorm-top IR brightness temperature, T(B), due to field of view effects. Profiles of cloud top height and T(B) across overshooting features indicate an adiabatic cloud surface lapse rate. However, one-dimensional cloud model results indicate that when comparing thunderstorm top temperature and height at different times or different storms, a temperature-to-height conversion of about 7 K/km is appropriate. Examination of mature storm evolution indicates that, during periods when the updraft is relatively intense, the satellite IR 'cold point' is aligned with the low-level radar reflectivity maximum, but during periods of updraft weakening and lowering cloud top heights, the satellite T(B) minimum occurs downwind with cirrus anvil debris. The growth period of a relatively weak cumulonimbus cluster is also examined with aircraft and satellite data.

Adler, R. F.↗
NASA NTRS1982

Estimating the temperature and height of overshooting thunderstorm tops from geostationary satellite infrared data

Information is presented on the extent to which the brightness temperature is overestimated. A revised version of the technique proposed by Adler and Markus (1982) for overcoming this problem is discussed, together with aspects of its application. GOES IR thunderstorm top observations are compared with high-resolution data. The technique described here to estimate the small-scale cloud top temperature from the GOES data corrects for most of the field-of-view effect but requires additional analysis and testing. When applied to a time sequence of a growing thunderstorm, the calculated cloud top temperature time profile is found to agree very well with a similar profile derived from stereo measurements.

Adler, R. F.↗