Spatiotemporal Analysis of Precipitation Frequency in Texas Using High-Resolution Radar Products

Precipitation is the main driver of the hydrological cycle and capturing its spatial and temporal variability is very due to its inherent intermittency in time and space. That is why significant measures are taken by the science community to come up with a better way of recording/estimating the spatial and temporal distribution of precipitation. NEXt Generation RADar (NEXRAD) is a network of 160 high-resolution Doppler weather radars covering conterminous United States. This study tries to examine, in detail, the evolution and spatial and temporal variability of precipitation events in the State of Texas over the last 15 years. NEXRAD Stage VI hourly data with a spatial resolution of 4kms and hourly temporal increment was used in the analysis. The state of Texas in average gets around 322 wet hours annually (3.7%). However, areas around the Houston Metropolitan receive as high as 876 wet hours in average annually. Generally, the Northern part of the Gulf Coast Region is the region with the highest average precipitation frequency whereas the western region is the driest region with as little as 80 wet hours in average annually. The year 2015 was found to have the highest precipitation frequency across the state with an average frequency of 6% (525 wet hours) and 2011 was the driest year with average precipitation frequency of 1.9%. The highest precipitation frequency was observed in summer with an average frequency of 4.1%. In summer, the Gulf Coast receives high rainfall frequency while in the winter the wettest region shifts to the area that borders with the State of Louisiana. The Mann-Kendal trend analysis shows that only 7.2% of the state showed a significant positive trend in rainfall frequency. The surprising finding is that most of the significant trend was shown in the western region of the state which is the driest region.