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A severe-storm intercept field program was held in Oklahoma and nearby parts of Texas during the 1987-88 spring seasons. The purpose of the experiment was to use, for the first time, a lowpower, portable, continuous-wave (CW), 3-cm Doppler radar to obtain wind spectra in tornadoes from a distance of less than 10 km. We discuss measurements of spectra we recorded in a tornado, a funnel cloud, and two wall clouds. Photographic documentation is also given to aid in the interpretation of our data. Wind speeds as high as 60 m s-1 were measured in the tornado. It was found that deploying the portable Doppler radar from a storm-intercept vehicle may increase substantially the number of measurements of wind speeds in tornadoes. The radar has recently been modified so that it has frequency modulation (FM) capability, and hence can obtain wind spectra within range bins. A plan is presented for using the radar to find the source of vorticity in tornadoes.

Single crystals of iron-doped KMgF3 show a strong axial EPR spectrum with partially resolved hyperfine structure. The spectrum arises from Fe'+ in a crystalline field of [100] axial symmetry. An electron-nuclear-double-resonance study of the hyperfine interaction gives positive support to the model previously proposed. The iron ion substitutes for a magnesium ion, and one of the surrounding six-nearest-neighbor Auorine ions is either missing or replaced by a charge-compensating impurity such as 0, thus giving rise to an axial distortion. The measured values for the spin-Hamiltonian parameters are D = 0.352 + 0.005 cm ', g~--2.0042+ 0.0005, and g, = 2.0120+ 0.0005, where g is axially symmetric about the symmetric axis of the crystalline-field parameter D. The nearest-neighbor hyperftne interaction constants are A, gh = 104.6+ 0.1 MHz and Ar/h = 55.7+ 0.1 MHz for the four "F ions in a (100) plane perpendicular to the symmetry axis of D, and A~(h = 43.2+ 0.5 MHz, A"/h = 24.6 + 0.1 MHz for the single ' F ion along the symmetry axis of D. It is assumed that the hyperfine interaction tensors are axially symmetric about their corresponding Fe-F bond directions.

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