Radar rainfall improvements based onRadar rainfall improvements based onRain gage informationRain gage information

Xiomara Y. OrtizXiomara Y. Ortiz

Objectives:Objectives:

•To determine the best elevation angle to analyze data from the NEXRad radar.

•To compare rain activity during one day in the wet season (August 10,2002) using NEXRad radar data and rain gauge data. This comparison is possible, using Rosenfeld tropical Z-R relationship (Z=250R1.2) for Tropical convective systems.

Data and elevation angle selectionData and elevation angle selection

• NEXRad radar gather information at different elevation angles. Usually the first elevation angle is between .35° and .5°. The second elevation angle is around 1.5° and the third angle is around 2.4°, etc.

• ARCGis was the software used to determine the blind spots of the radar caused by the elevation of the terrain along the island.

• NEXRad data to be used is Level II at an elevation angle of 5º which is the most adequate angle to use based in Puerto Rico’s topography.

Data and elevation angle selectionData and elevation angle selection

Data and elevation angle selectionData and elevation angle selection

Blockage area

Data and elevation angle selectionData and elevation angle selection

Data and elevation angle selectionData and elevation angle selection

Blockage area

Data and elevation angle selectionData and elevation angle selection

Data and elevation angle selectionData and elevation angle selection

Hurricane Georges and loss of data due to elevation angle

.40° 1.45°

Hurricane Georges and loss of data due to elevation angle

.40°

Hurricane Georges and loss of data due to elevation angle

1.45°.40°

Hurricane Georges and loss of data due to elevation angle

Comparison between NEXRad and rain Comparison between NEXRad and rain gaugesgauges

Comparison between NEXRad and rain Comparison between NEXRad and rain gaugesgauges