## 4 Results and Discussion
### Impact of Different Scatterometer Product Resolutions
Figure 3 depicts the wind retrievals for ASCAT products of 50-km spatial resolution after the directional ambiguity removal (Figure 3a,b), along with the available wind solutions (Figure 3c-f) obtained through the GMF. Wind solutions 3 and 4 exhibited increased wind variability and are not presented here, as these solutions suffered from a known effect of rain, i.e., the alignment of the wind vectors perpendicular to the satellite track [64,65]. Wind retrievals at 50-km resolution are absent close to the coast due to potential land contamination. The wind field for both ASCAT-A and -B wasoutheasterly over the precipitation system (Figure 3a,b). The ECMWF model winds, used during the ambiguity removal process, also indicated southeasterly flow over the whole domain (Figure 7a,b), failing to resolve the mesoscale system. Over the same area single-Doppler analysis wind field indicated northwesterly flow (Figure 3a; red streamlines). The correction method described in the methodology section was applied to rainfalled ASCAT wind vectors, offshore of Houston, where the ambiguity removal process most likely failed. Around \(28.7\deg N\) and \(94.5\deg W\) wind retrievals were flagged by the MLE for both ASCAT-A and -B (Figure 3c-f; gold vectors), indicating large distance between the ambiguous solution 1, 2 from the GMF and ECMWF background winds. Large values for the MLE might indicate that the retrieval is contaminated by rain or confused sea state. Not surprisingly, this area was severely affected by high rain rates (Figure 2e; 70 mm h\({}^{-1}\)), therefore the Doppler retrievals should have been more representative of the wind field than the scatterometer winds. In the absence of any other observations, the observed sounding at KLCH station at 12 UTC indicated a uniform wind flow (southwesterly) up to height of 1.5 km, therefore the correction method was applied to scatterometer wind vectors up to 100 km radial distance from the radar location. For example, the first wind solution for ASCAT-A (Figure 3c) captured north-northwest wind direction over the respective region, whereas the second wind solution (Figure 3e) indicated south-southeast wind direction, with the latter being the solution selected by the ambiguity process. The single-Doppler analysis wind field (Figure 2c) captured north-northwest wind direction over an area that expanded radially outwards from the location of the radar. For each wind vector cell that fell within the radar domain, the wind direction of the optimal solution was substituted with the Doppler-compliant unambiguous wind direction; i.e., north-northwest (Figure 3c, wind solution 1). The suggested wind solution was was then constructed for all ASCAT wind retrievals at 50-km. The aforementioned approach was applied to the 25-km spatial resolution product (Figure 4). Wind retrievals were available closer to the coast, but the wind vectors exhibited significant variability in comparison to the coarser resolution, owing to the presence of the precipitating system. Once again, the ambiguity selection process likely erroneously indicated southerly flow over the radar-derived streamlines for both ASCAT-A (Figure 4a) and -B (Figure 4b). In front of the MCS all three ASCAT products showed a response by the winds to the cold-pool outflow (Figure 6). The valid wind retrievals at all 3 spatial resolutions indicated southeastery flow over the open ocean. At the overpass of MetOp-A satellite, winds at 50-km resolution captured a sudden shift in the wind direction from southeastery to northerly flow along the border of the precipitating system (Figure 6a, blue-dotted line), and an increase in the wind speed from 10 to 18 m s\({}^{-1}\). The system was characterized by high rainfall rates, reaching a local maximum of 130 mm h\({}^{-1}\). Over the precipitation region the wind vectors were characterized by increased speed and northerly flow, though the increase in the wind speed could be attributed to the effect of rain on scatterometers [27; 65; 66; 67].