Device name Operating range Agilent 34970a data logger -150[degrees]C to (for J-type thermocouple) 1200[degrees]C Temperature sensors -210[degrees]C to (J-type thermocouples) 760[degrees]C KIMO SL100 solarimeter
1 W/[m.sup.2] to 1300 W/[m.sup.2], -10[degrees]C to +50[degrees]C TFA sinus Ambient temperature -40[degrees]C to weather +80[degrees]C station Wind speed 0 m/s to 90 m/s TABLE II.
The radiometers used were solarimeters
tubes type, made of printed circuit boards, similar to those used by Duarte et al.
Sensors were at 1.5 m above the surface except the rain gage that was at 0.9-m height, and were connected to the same datalogger as the solarimeters
and the pyranometer.
Thermocouples and solarimeters
(Delta-T Devices Ltd., Cambridge, England; Szeicz et al., 1964)(1) were installed at 1 and 15 m from two Faidherbia albida trees to measure soil temperature and solar radiation inside and outside of the tree canopy.
In addition, in 1997 the hourly averages of incident solar radiation above the crop were recorded using two tube solarimeters
from mid-April to mid-July.
Radiant flux above each plot was measured with tube solarimeters
(DeltaT Devices) during the sunniest time of the year (20 December 1993 to 20 March 1994).
The following parameters were measured daily at each site: maximum, minimum and average air temperatures and relative humidity (Campbell Model 201 temperature-humidity probes), incoming short-wave radiation (Monteith solarimeters
) and windspeed (Met-One 013A anemometers), at a height of 1.5 m, and soil temperatures (Campbell Model 101B temperature probes) at 10, 50 and 100-cm depths.
Total daily solar radiation at 1.0 m above the forest floor was measured with solarimeters
connected to millivolt integrators (Delta-T Devices, model TSLF, Burwell, Cambridge, UK).
Solar irradiance was monitored with a Delta-T (Delta-T Devices Ltd., Cambridge, UK) (1) system consisting of 10 TSL tube solarimeters
(spectral response 0.35 to 2.5 [micro]m) connected to a DL2e logger.
1 showed that this equation yields estimates of daily light interception that are statistically indistinguishable from estimates based on continuous measurements of light interception obtained with tube solarimeters
(Sadras, 1994, unpublished data).