Figure 2 shows the calibrated NEXRAD coverage area with a color map indicating total 2019 rainfall for each 16-km 2 pixel. The resulting product is a dataset of hourly rainfall totals for a grid of 4 km × 4 km pixels over the entire region of interest that extends back to January 1, 2003. For this reason, EAA takes a two-step approach by performing a quality review of the rain gauge data each month and using the operational rain-gauge data as a “ground-truth” to calibrate the NWS NEXRAD data. However, NEXRAD measures reflectivity of precipitation near ground level and not the actual amount of precipitation as measured by rain gauges. NEXRAD (Next-Generation Radar) data from the National Weather Service (NWS) provides a potential solution to the limitations of individual rain gauges because it provides continuous coverage of the entire region based on overlapping coverage from NEXRAD Doppler radar stations in Brackettville, Corpus Christi, New Braunfels, and Granger, Texas. Additionally, gauges are susceptible to occasional malfunctions such as clogging, battery or electronic failure, or physical damage. Rainfall can vary greatly over relatively short distances and a gauge only reflects rainfall at a specific point.
In general, rain gauges are not always reliable indicators of total rainfall over a region. The locations of the EAA rain gauges are shown in Figure 1. Collected over several years or decades, the extensive database of rainfall information can also be useful for monitoring climate trends, evaluating relationships between rainfall and aquifer levels, or for understanding how global-scale phenomena such as “El Nino” (which refers to above- average sea surface temperatures in the equatorial region of the Pacific Ocean) may affect rainfall in Central Texas. Rainfall data is used as input for watershed computer models that can provide estimates of monthly recharge to the aquifer. 2019 Precipitation in the Edwards Aquifer Region The Edwards Aquifer Authority (EAA) monitors precipitation throughout the region using a network of 74 real-time rain gauges.
0 kommentar(er)
