Event Title

Evaluation of Two New Net Radiometers

Presenter Information

J. Mark Blonquist Jr.

Location

ECC 307/309

Event Website

https://water.usu.edu/

Start Date

4-1-2008 11:30 AM

End Date

4-1-2008 11:45 AM

Description

Net radiation is a key component to the surface energy balance, but it is difficult and expensive to measure accurately. Two new net radiometer models (Hukseflux NR01 and Kipp & Zonen CNR 2) have been released in the past year. We evaluated and compared these models to each other, a Kipp and Zonen model CNR 1 net radiometer, and to two less expensive, older model net radiometers (Kipp & Zonen NR-Lite and REBS Q*7.1). Hourly averages and daily totals (over the course of the study; 33 days) from three replicate sensors of the two new net radiometers compared quite well to the CNR 1 radiometer. The difference was generally less than +/- 5 %. Three replicates of the two older model net radiometers did not agree as well with the newer models, particulary at night, with differences generally less than +/- 10 % during the day and +/- 20 % at night. Our data matched what others (Cobos and Baker, 2003; Brotzge and Duchon, 2000) have shown for these older radiometers. Our findings indicate that accuracy increases with increasing cost. Accurate net radiation measurements depend on proper placement of the sensor, proper leveling, and routine maintenance to keep the sensing surfaces clean.

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Apr 1st, 11:30 AM Apr 1st, 11:45 AM

Evaluation of Two New Net Radiometers

ECC 307/309

Net radiation is a key component to the surface energy balance, but it is difficult and expensive to measure accurately. Two new net radiometer models (Hukseflux NR01 and Kipp & Zonen CNR 2) have been released in the past year. We evaluated and compared these models to each other, a Kipp and Zonen model CNR 1 net radiometer, and to two less expensive, older model net radiometers (Kipp & Zonen NR-Lite and REBS Q*7.1). Hourly averages and daily totals (over the course of the study; 33 days) from three replicate sensors of the two new net radiometers compared quite well to the CNR 1 radiometer. The difference was generally less than +/- 5 %. Three replicates of the two older model net radiometers did not agree as well with the newer models, particulary at night, with differences generally less than +/- 10 % during the day and +/- 20 % at night. Our data matched what others (Cobos and Baker, 2003; Brotzge and Duchon, 2000) have shown for these older radiometers. Our findings indicate that accuracy increases with increasing cost. Accurate net radiation measurements depend on proper placement of the sensor, proper leveling, and routine maintenance to keep the sensing surfaces clean.

https://digitalcommons.usu.edu/runoff/2008/AllAbstracts/39