Synoptic views of the entire polar regions of Earth have been obtained free of the usual persistent cloud cover using a scanning microwave radiometer operating at a wavelength of 1.55 cm on board the Nimbus-5 satellite. Three different views at each pole are presented utilizing data obtained at approximately one-month intervals during December 1972 to February 1973. The major discoveries resulting from an analysis of these data are as follows: 1) Large discrepancies exist between the long-term ice cover depicted in various atlases and the actual extent of the canopies. 2) The distribution of multiyear ice in the north polar region is markedly different from that predicted by existing ice dynamics models. 3) Irregularities in the edge of the Antarctic sea ice pack occur that have neither been observed previously nor anticipated. 4) The brightness temperatures of the Greenland and Antarctic glaciers show interesting contours probably related to the ice and snow morphologic structure.
Firing of ten Aerobee rockets, each carrying 18 to 19 high‐explosive grenades at Fort Churchill, Canada, have resulted in the accurate measurement of temperatures and winds in the atmosphere up to 95 km during November 1956, July, August, and December 1957, and January 1958. One hundred and fifty measurements of temperatures and of winds were made over the period. Each measurement represents the average temperature and wind of an atmospheric layer of about 3‐km thickness. The results show clearly a seasonal variation, with average summer temperatures of 275°K at the mesopeak (about 50 km) and 170°K at the mesopause (about 80 km); corresponding average winter temperatures are 260°K and 230°K.
In summer, prevailing winds above 25 km were from the east, usually less than 50 m/sec. In winter these winds were from the west, usually between 50 and 100 m/sec but frequently exceeding 100 m/sec.
A breakdown in circulation up to 80 km is indicated by the wind results of two firings on January 27, 1958, where strong northerly and southerly wind components were measured. This phenomenon coincides with the occurrence of sharp temperature increases at stratospheric levels over large parts of the northern hemisphere east of Churchill.
Remarkable temperature inversions between 50 and 80 km were measured in all winter firings. These inversions resulted in secondary temperature peaks above 50 km. On December 11, 1957, the temperature at 72 km was about 290°K.
In summer, temperatures at 50 km and below at Churchill (59°N) were higher than at White Sands (33°N); above 65 km the Churchill temperatures were lower. This picture is reversed in winter.
Only minor diurnal temperature variations were detected. No sound energy from detonations of 4‐pound high‐explosive charges above 95 km was detected on the ground with microphones of 1‐dyne cm2 sensitivity in the frequency range 8 to 25 cycles/sec.
A combination of remote sensing from an aircraft and simultaneous surface measurements have confirmed the feasibility of identifying old and new sea ice according to its emission of thermal radiation at wavelengths between 0.3 and 3 cm. Emissivity of first‐year thick ice with a surface temperature of about 260°K is 0.95 or greater for wavelengths between 0.81 and 11 cm; the emissivity of multiyear ice is 0.8 at 0.81 cm and 0.95 at 11 cm, increasing monotonically in this wavelength interval. The ease with which multiyear ice can be distinguished from first‐year ice using a passive microwave radiometer is demonstrated by comparing mosaics prepared both from photographs and images of 1.55‐cm radiation.
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