Characteristics of Wind Fields Derived from the Multiple-Doppler Synthesis and Continuity Adjustment Technique (MUSCAT)

Abstract

 Characteristics of wind fields derived from multiple-Doppler synthesis and continuity adjustment technique (MUSCAT) and MUSCAT substituting mass flux conservation for the continuity equation are investigated mainly on the basis of the numerically simulated Doppler velocity data, assuming a ground-based dual-Doppler synthesis over a flat plane. The gain factor and the accuracy of the wind components are discussed for MUSCAT and the conventional synthesis. A modified formulation of data fit is tested, and found to be useful. The results of numerical experiments employing height-independent two-dimensional pure divergent wind fields show that the wind components around the surface exhibit similar accuracy, regardless of whether MUSCAT is used with the continuity equation or mass flux conservation. In both cases, the results are more accurate than those obtained from the conventional synthesis as far as the gain factors are close to unity. In a three-dimensional volume, in which the height-dependent two-dimensional wind fields are defined by their horizontal and vertical components, MUSCAT provides more accurate determination of wind components than the conventional method.
 Finally, MUSCAT is applied to a wind recovery from Doppler radar data collected for a shallow convective snow band over the Sea of Japan in 1993. The results indicate that the vertical wind fields are affected most extensively by the type of mass conservation adjustments and by the weighting factor applied to the filter term. This suggests that these should be appropriately chosen to ensure better wind recovery in certain cases.