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Comparison of radar data versus rainfall data.

Espinosa B, Hromadka TV, Perez R - MethodsX (2015)

Bottom Line: Because the subject storms were very intense rainfall events lasting approximately one hour in duration, direct comparisons between the three radar gages themselves can be made, as well as a comparison to rain gage data at a rain gage location subjected to the same storm cells.It is shown that topographic interference with the radar outcomes can be a significant factor leading to differences between radar and rain gage readings, and that care is needed in calibrating radar outcomes using available rain gage data in order to interpolate rainfall estimates between rain gages using the spatial variation observed in the radar readings.The paper establishes and describes•the need for "ground-truthing" of radar data, and•possible errors due to topographic interference.

View Article: PubMed Central - PubMed

Affiliation: Hromadka & Associates, 29809 Santa Margarita Parkway Suite 102, RSM, CA 92688, United States.

ABSTRACT
Doppler radar data are increasingly used in rainfall-runoff synthesis studies, perhaps due to radar data availability, among other factors. However, the veracity of the radar data are often a topic of concern. In this paper, three Doppler radar outcomes developed by the United States National Weather Service at three radar sites are examined and compared to actual rain gage data for two separate severe storm events in order to assess accuracy in the published radar estimates of rainfall. Because the subject storms were very intense rainfall events lasting approximately one hour in duration, direct comparisons between the three radar gages themselves can be made, as well as a comparison to rain gage data at a rain gage location subjected to the same storm cells. It is shown that topographic interference with the radar outcomes can be a significant factor leading to differences between radar and rain gage readings, and that care is needed in calibrating radar outcomes using available rain gage data in order to interpolate rainfall estimates between rain gages using the spatial variation observed in the radar readings. The paper establishes and describes•the need for "ground-truthing" of radar data, and•possible errors due to topographic interference.

No MeSH data available.


Radar station KNKX San Diego published rainfall estimate (storm total for storm event 8/25/13 at rain Gage 296 = 1.17 in.).
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fig0020: Radar station KNKX San Diego published rainfall estimate (storm total for storm event 8/25/13 at rain Gage 296 = 1.17 in.).

Mentions: Fig. 3, Fig. 4, Fig. 5 show the common radar presentations of the daily rainfall for each of the three radar stations. Looking at the radar data in the table above and the pictorial presentations of that data in the figures below, a significant discrepancy is readily seen at the Gage 296 location. If one were to strictly rely upon the Doppler radar estimates of rainfall from KSOX Santa Ana, the storm of August 25, 2013 would appear to have been a minor event with 0.10 in. of rainfall falling in the peak hour. However, from the Doppler radar station KYUX Yuma published results, 2.09 in. of rainfall during the peak hour is indicated. In order to determine which radar station outcome gives a more accurate description of the storm event, a comparison is made of published rainfall estimates from each radar station to the actual rainfall data collected at a rain gage (Gage 296). This concept of “ground-truthing” radar data, by comparing it to actual rainfall data recorded at a gage, is well described in the literature. For this storm (see Table 1), we see that the KYUX radar station rainfall estimates correlate well to the rainfall data collected by Gage 296 for both the Storm Total for the day (midnight to midnight), as well as the Peak Hour measurements. (It is noted that the storm is essentially a 1 h duration event.)


Comparison of radar data versus rainfall data.

Espinosa B, Hromadka TV, Perez R - MethodsX (2015)

Radar station KNKX San Diego published rainfall estimate (storm total for storm event 8/25/13 at rain Gage 296 = 1.17 in.).
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644244&req=5

fig0020: Radar station KNKX San Diego published rainfall estimate (storm total for storm event 8/25/13 at rain Gage 296 = 1.17 in.).
Mentions: Fig. 3, Fig. 4, Fig. 5 show the common radar presentations of the daily rainfall for each of the three radar stations. Looking at the radar data in the table above and the pictorial presentations of that data in the figures below, a significant discrepancy is readily seen at the Gage 296 location. If one were to strictly rely upon the Doppler radar estimates of rainfall from KSOX Santa Ana, the storm of August 25, 2013 would appear to have been a minor event with 0.10 in. of rainfall falling in the peak hour. However, from the Doppler radar station KYUX Yuma published results, 2.09 in. of rainfall during the peak hour is indicated. In order to determine which radar station outcome gives a more accurate description of the storm event, a comparison is made of published rainfall estimates from each radar station to the actual rainfall data collected at a rain gage (Gage 296). This concept of “ground-truthing” radar data, by comparing it to actual rainfall data recorded at a gage, is well described in the literature. For this storm (see Table 1), we see that the KYUX radar station rainfall estimates correlate well to the rainfall data collected by Gage 296 for both the Storm Total for the day (midnight to midnight), as well as the Peak Hour measurements. (It is noted that the storm is essentially a 1 h duration event.)

Bottom Line: Because the subject storms were very intense rainfall events lasting approximately one hour in duration, direct comparisons between the three radar gages themselves can be made, as well as a comparison to rain gage data at a rain gage location subjected to the same storm cells.It is shown that topographic interference with the radar outcomes can be a significant factor leading to differences between radar and rain gage readings, and that care is needed in calibrating radar outcomes using available rain gage data in order to interpolate rainfall estimates between rain gages using the spatial variation observed in the radar readings.The paper establishes and describes•the need for "ground-truthing" of radar data, and•possible errors due to topographic interference.

View Article: PubMed Central - PubMed

Affiliation: Hromadka & Associates, 29809 Santa Margarita Parkway Suite 102, RSM, CA 92688, United States.

ABSTRACT
Doppler radar data are increasingly used in rainfall-runoff synthesis studies, perhaps due to radar data availability, among other factors. However, the veracity of the radar data are often a topic of concern. In this paper, three Doppler radar outcomes developed by the United States National Weather Service at three radar sites are examined and compared to actual rain gage data for two separate severe storm events in order to assess accuracy in the published radar estimates of rainfall. Because the subject storms were very intense rainfall events lasting approximately one hour in duration, direct comparisons between the three radar gages themselves can be made, as well as a comparison to rain gage data at a rain gage location subjected to the same storm cells. It is shown that topographic interference with the radar outcomes can be a significant factor leading to differences between radar and rain gage readings, and that care is needed in calibrating radar outcomes using available rain gage data in order to interpolate rainfall estimates between rain gages using the spatial variation observed in the radar readings. The paper establishes and describes•the need for "ground-truthing" of radar data, and•possible errors due to topographic interference.

No MeSH data available.