Hawaii Ocean Time-series (HOT)
in the School of Ocean and Earth Science and Technology at the University of Hawai'i

Profiling Reflectance Radiometer (PRR)

DISCONTINUED

PRR
FTP View Data
To assist in the interpretation of the data, it can be displayed using the Hawaii Ocean Time-series Data Organization & Graphical System (HOT-DOGS©).

Analytical Method

Vertical profiles of upwelling radiance and downwelling irradiance were made using a Biospherical PRR-600 Profiling Reflectance Radiometer. Surface irradiance was collected using a sister instrument (PRR-610). These instruments measures downwelling irradiance (Ed) and upwelling radiance (Lu) as well as surface irradiance (Es) from a deck unit on 7 wavelength channels (Table below). The radiance channels comply with the SeaWIFS satellite optical parameters. The instrument is lowered by hand and depending on the subsurface currents, is deployed to a depth between 125 and 175 meters.


Channel Downwelling
(Ed)
Upwelling
(Lu)
Surface
(Es)
1 412 412 412
2 443 443 443
3 490 490 490
4 510 510 510
5 555 555 555
6 665 665 665
7 PAR 683 PAR

Results

Figure 58 shows a time-series of the 1% light level and KPAR during the 18 years we've been collecting in-situ PAR data. Both vary seasonally. Data for HOT cruises 90-214 were collected using a Biospherical PRR-600, while cruises 215 (Sep 09) onward used a Satlantic HyperPro. The average 1% light-level at Station ALOHA is 106.0 m while the average KPAR between 100 & 150m is 0.0437 m-1. Downwelling irradiance measured during the Primary Production incubation period is shown in Table xxx. The results compare favorably with the integrals obtained using the LICOR LI-1000 which also measures PAR.

This study is a collaborative effort between the College of Oceanic and Atmospheric Sciences of Oregon State University and the Laboratory for Microbial Oceanography of the University of Hawai'i at Manoa.