Over 50 cases of TIROS-viewed cloud vortices associated with extratropical cyclones over North America, Europe and Asia between April 1962 and November 1963 were examined to determine what meteorological information could be derived from the satellite pictures. Radiosonde stations were grouped in five principal classes according to their time-adjusted positions with reference to the vortex center and the major cloud bands. Meteorological parameters were statistically related to the age of the vortex, season, and geographical location as Well as to the principal sounding class for the position of the station. The thermal results indicated that the means of the dew-point depression for each principal class were significantly different from the overall mean of the sample, according to the analysis of variance test. Relative tropopause heights were estimated from the means and variances of the vertical temperature differences. These results will be of value as input parameters for numerical prediction over data-silent areas. The wind results showed that the wind directions within 333 km ahead of the major cloud band aids averaged 16° clockwise from the nearest band orientation, and behind the bands, 25° clockwise. The mean vertical wind shears within the major cloud bands and in the dry zones behind the bands were about 60° and 20°, respectively, clockwise from the band orientation. Most of the cloud bands were characterized by a speed convergence of the normal components and by a cyclonic shear and vorticity of the parallel components of the mean winds on the two sides of the bands.

A four-channel multispectral cloud type identification technique is developed on the basis of Nimbus-3 Resolution Infrared Radiometer (MRIR) measurements, with the four channels being spectrally located at 0.2-4.0, 6.5-7, 10-11, and 20-23 microns. The technique requires the use of a radiative transfer model with information on the vertical temperature and moisture profiles and climatological knowledge of the upper boundaries of cloud surfaces associated with expected cloud types within a given area. Experimental verification of the technique indicates that deletion of the 20-23 micron channel has no adverse effect on method capability, and that the 6.5-7 micron channel alone is well suited for successful mapping of the areas where cirrus is reasonably dense, while indicating the regions where cirrus is not present.

For more than the past two decades and for the foreseeable future measurements from geosynchronous satellites will be a major contributor to the determination of winds, especially over oceanic areas. The winds can be determined from features (e.g. clouds) that closely follow the air motion, and from the thermal wind relationship poleward of the tropics. Major improvements in accuracy and coverage should be possible during the coming decades through the combination of better sensors and their operation and the increased use of interactive systems. These data could contribute significantly to a long-term wind data base associated with global change studies.

During the 1975, 1976 and 1977 North Atlantic hurricane seasons, NOAA's National Environmental Satellite Service (NESS) and NASA's Goddard Space Flight Center (GSFC) conducted a cooperative program to determine the best resolution and frequency now available from satellite images for deriving winds to study and forecast tropical cyclones. Rapid-scan images were obtained in 1975 at 7.5 min interval from SMS 2 for Hurricane Eloise on 22 September and of tropical cyclone Caroline on 28, 29 and 30 August; in 1976 at 3 min intervals from GOES 1 for tropical storms Belle on 5 August and Holly on 25 October; and in 1977 at 3 min intervals Corn GOES 1 for tropical cyclone Anita on 30 and 31 August and 1 September. Cloud motions were derived from these images using the Atmospheric and Oceanographic Information Processing System (AOIPS) at GSFC. Winds that were derived from the movement of upper (∼200 mb) and lower tropospheric (∼900 mb) level clouds using rapid scan data were compared with the 15 and 30 min interval data. This was done using visible images having 1, 2, 4 and 8 km resolution for the areas within 650 km of the storm center for the 1975 and 1976 tropical cyclones. Greater than 10 (5) times as many clouds could be tracked to obtain winds at both levels using 3 and 7.5 min rapid-scan images as when using 30 min (15 min) interval images. In addition, by using the frequent images, it was possible to track a few bright areas within the central dense overcast which appeared to be moving with the winds at low levels. For Hurricanes Eloise and Caroline the winds that were derived by tracking these bright areas within the central dense overcast had speeds differing in the mean by only 2.5 m s −1 from the wind speed measured by aircraft flying at ∼0.5 km above the surface in the same quadrant 4 h later. Full-resolution visible images (1 km) were needed to track slow moving low-level cloud elements, since on a degraded resolution image, subpixel movement would introduce additive inaccuracies to the wind measurements. Rapid-scan full-resolution GOES 1 data for tropical cyclone Anita (1977) provided representative wind fields only outside the central dense overcast at the lower tropospheric level. For this area aircraft-measured wind speeds differed in the mean again by only 2.5 m s−1.

A two-channel method has been developed to estimate the altitude of cirrus clouds over ocean areas with an expected altitude error less than or equal to plus or minus 50 mb. Reflected radiation is used to estimate cirrus emissivity in the 10- to 11-micron spectral interval. The cirrus altitude is determined from the emissivity estimate, a registered 10- to 11-micron measurement, and a vertical temperature profile. Nimbus 3 medium-resolution infrared radiometer measurements were used to establish the relationship between reflectance and 11-micron cirrus emissivity.

The origin of a small, tight cloud vortex located over the Caspian Sea as viewed by TIROS VII in late November 1963 was investigated. Charts at the mandatory levels from the surface to 500 mb. at 12-hr. intervals were examined. Possible causes of formation that were investigated included upper air circulation effects, mechanical effects induced by the Caucasus Mountains, surface heating from the sea, and association with a cold front. Evidence is presented that the cloud vortex was associated with a frontless circulation. A well-defined upper-level wind circulation is believed to be the major cause for the formation of the cloud spiral.

The difference between observed window radiation and radiation expected without clouds was related to various synoptic parameter. The but correlation, 0.72, was obtained with vertical motion computed by the adiabatic methods at 700 mb. Other variables tested were meridional flow and vertical motion at other level.