{'fraction_non_alphanumeric': 0.02531645569620253, 'fraction_numerical': 0.006815968841285297, 'mean_word_length': 5.192771084337349, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
1 Single-Doppler Velocity Retrievals and Their Applications

Doppler radar has long been a valuable observational tool in meteorology. It has the capability of observing, at high spatial and temporal resolution, the internal structure of convective storm systems from remote locations. However, the direct measurements are limited to reflectivity and the radial component of velocity; there is no direct measurement of the complete three-dimensional (3D) wind field. To initialize storm-resolving numerical models, it is desirable to know the full wind field. Techniques for retrieving 3D wind fields given single-Doppler observations of radial velocity and reflectivity have been developed in recent years, many at the Center for Analysis and Prediction of Storms (CAPS), University of Oklahoma. To overcome the under-determinedness of the problem, almost all methods make use of data at multiple time levels and they are usually based on certain assumptions. A review of some of these methods can be found in Shapiro (1995a).