Campbell-scientific OBS-5+ Sediment Concentration Monitor and Pressure Instrukcja Użytkownika Pobierz pdf (Strona 43)

OBS-5+ System

FIGURE 10-1. Effects of sediment size

10.2 NIR Reflectivity

The output of an OBS-5+ will increase with the NIR reflectivity of suspended

sediment independent of SSC. This can degrade accuracy when unknown

reflectivity changes occur during a monitoring campaign. For instance, when a

dredge cuts through a layer of oxidized, light-brown, reflective mud into an

underlying layer of black anoxic mud, the OBS-5+ will indicate that SSC of

mud stirred up by the cutter has dropped even when it has not. The relative

signal level per unit of SSC varies from a low of about one for dark, non-

reflective sediment to a high of about ten for white, reflective sediment

(FIGURE 10-2). In areas where sediment color changes with time, more than

one calibration curve may be required to measure SSC with an OBS-5+.

1 2 ... 38 39 40 41 42 43 44 45 46 47 48 ... 51 52

Brak uwag

Campbell-scientific OBS-5+ Sediment Concentration Monitor and Pressure Instrukcja Użytkownika Strona 43