# Comparing Winds near Tropical Oceanic Precipitation Systems with and without Lightning
## 3 Results
### Lightning Analysis
#### 3.2.3 Trends versus Flash Rates  
Figure 6 shows behavior of CYGNSS and ASCAT wind differences above background as functions of lightning flash rate. For CYGNSS, both FDS and YSLF wind speed differences decrease when WWLLN flash rates increase slightly above 0 min\({}^{-1}\) (Figure 6a). This confirms the results in Table 2, where wind speeds associated with lightning were less than when lightning was present. However, as flash rate increases above 1 min\({}^{-1}\), a quasi-linear increase in wind speed difference is observed, particularly for YSLF winds. However, uncertainty also increases since the number of high-flash-rate samples is low relative to 0-2 min\({}^{-1}\) flash rates. ASCAT observes a sharper increase in wind speed difference as flash rate increases (Figure 6b); however, when controlling for higher rain rates (>6 mm h\({}^{-1}\)) the trend is almost flat until about 20 min\({}^{-1}\), when the lack of samples begins to lead to dubious results.  
Interestingly, CYGNSS wind differences show very little variability relative to GLM flash rates above ~1 min\({}^{-1}\) (Figure 6a). The initial decrease between 0 and 1 min\({}^{-1}\) is observed, similar to WWLLN (Figure 6a), but above that range the relationship is essentially flat for both FDS and YSLF winds. Analogous behavior to WWLLN is observed for ASCAT wind differences versus GLM flash rates (Figure 6d). Once again a positive relationship is observed when not controlling for precipitation, but when controlling for heavier precipitation the ASCAT relationship is much flatter, similar to CYGNSS. Note that GLM provided more samples at higher flash rates (>20 min\({}^{-1}\)) since it is a total flash rate instrument, unlike WWLLN.  
ISS LIS shows a weak positive relationship between FDS and YSLF wind differences and flash rate up to about 30 min\({}^{-1}\), and the initial decrease in wind difference between 0 and 1 min\({}^{-1}\) is not as strong compared to WWLLN and GLM (Figure 6e). However, uncertainty in this possible relationship is large enough that it cannot be distinguished from the complete lack of a relationship, based on the spreads of the 99% confidence intervals. ASCAT winds also show a positive relationship with flash rate, even when controlling for precipitation (Figure 6f). However, since ISS LIS provided fewer overall samples it is possible that these relationships are not robust. The 99% confidence interval spread for the ASCAT data is very large.  
Figure 6: (**a**) CYGNSS FDS and YSLF wind differences as functions of WWLLN flash rate. (**b**) ASCAT wind differences as functions of WWLLN flash rate, for ASCAT observations associated with all precipitation rates and for ASCAT observations with precipitation rate \(<\) 6 mm h\({}^{-1}\). (**c**) CYGNSS FDS and YSLF wind differences as functions of GLM flash rate. (**d**) ASCAT wind differences as functions of GLM flash rate, for ASCAT observations associated with all precipitation rates and for ASCAT observations with precipitation rate \(<\) 6 mm h\({}^{-1}\). (**e**) CYGNSS FDS and YSLF wind differences as functions of GLM flash rate. (**f**) ASCAT wind differences as functions of GLM flash rate, for ASCAT observations associated with all precipitation rates and for ASCAT observations with precipitation rate \(<\) 6 mm h\({}^{-1}\). In all figures, the shaded areas indicate the 99% confidence interval in each 1 min\({}^{-1}\) bin.