## 4 Discussion
### Wetland Persistence and Dry Season Rainfall  
The development of a spatially and temporally dynamic wetland classification in Section 2 permits an evaluation of wetland persistence under different wet and dry precipitation regimes. Wetland persistence is defined as the continuation of wetland areas past the onset of the dry season (i.e., May). The persistence of the UZRB midland wetlands is of particular interest due to the occurrence of localized rainfall events during wet years over this region (Figure 9, Figure S3). Dry years tend to have very low wetland persistence past the month of June (DOY 180, Figure 10 and Figure S3). The year 2004 shows an area around \(-15.25^{\circ}\) latitude where 40-50% of the wetland area continues through August. This appears to be a case where remote groundwater contributions are playing a role, as there are no significant precipitation events occurring along this transect between May and August of 2004, and groundwater deficits nearly subside during the dry season in 2004 ([PERSON] et al., 2010). In wet years, high wetland fractions persist over large areas within the UZRB midlands (Figure 11, Figure S4). Figure 9: Minimum, maximum, and mean monthly rainfall accumulations along a transect within the UZRB for April and May in a wet year (2006) and a dry (2010) year. The minimum, maximum, and average elevations along the transect positioned between \(22.7^{\circ}\) and \(24^{\circ}\) longitude are displayed. In order to better understand how the persistence of wetlands relates to localized rainfall events in the transition season, we evaluate the average diurnal cycles of local rainfall events around the midland wetlands. The rainfall accumulations from TRMM 3B42 consistently demonstrate a dual-peak in the diurnal cycle of rainfall in the early morning around 7-9 a.m. LST and in the afternoon between 5-8 p.m. LST in the transition season April-June (Figure 12, Figure S5). The bimodal diurnal pattern observed in the TRMM data is consistent with wet season low level cloud and fog formation patterns in the morning and late afternoon thunderstorms [83]. A word of caution is necessary to highlight the relatively coarse resolution of TRMM 3B42 at approximately 25 km\({}^{2}\), which explains the very low rainfall rates per unit area in the diurnal cycle estimates (see also Figure S5). Further evaluation of these rainfall events using TRMM Precipitation Radar (PR) reflectivity (2A25 product) shows that the morning events are very shallow events with low reflectivity corresponding to radiation fog and low level clouds formed over the inundated areas in the early morning (Figure 13). Afternoon events  
Figure 10: Wetland persistence in dry years. These plots show the maximum wetland fraction along a transect located between 22.7\({}^{\circ}\) and 24\({}^{\circ}\) longitude. The subset area is displayed in Figure S1. In years 2002–2006 most wetland areas dry rapidly after the end of May (approximately day 150). Only very small areas persist until later in the dry season. Höwemöeller diagrams of rainfall in dry years over the same region are presented in Figure S3. correspond mostly to isolated shallow convection (<5 km height, not shown) with deeper convection features and higher intensity localized storms in the beginning of the transition season through early May (e.g., Video S4 for May 2009) as illustrated by the TRMM PR overpass example shown in Figure 13 for May 2008. Note the daily re-occurrence of isolated precipitation cells in the midland wetland region (highlighted by purple box in Figure S1). The TRMM 3B42 daily rainfall accumulations at approximately 25 \(\times\) 25 km\({}^{2}\) is relatively low, but the reflectivity profiles from TRMM 2A25 at 5 \(\times\) 5 km\({}^{2}\) suggest co-organization of individual afternoon rainfall cells and wetland pixels at high spatial resolution.