Lehigh Weather Station 1, Goodman Campus (part of WeatherNet)
Lehigh University Weather and Stream Monitoring Stations (Lehigh Valley, Pennsylvania, USA)

Welcome to the instrument charecteristics site of the CR 10x
	Equiptment Datalogger:                  Campbell Scientific CR10X Communication:           Proxim RangeLAN2 spread spectrum radio modem linked to                                                  telephone modem in Goodman Pressbox Power:                        two 7AHr batteries, 10 W solar panel Sensors:                      Met3 wind spreed and direction                                        Vaisaila HMP45C tempeture and % relativehunidity                                        Vaisaila barometer (calibrated for ambient pressure;                                         not corrected to sea level)                                        CSI 108 thermister (Tair2 and Tsoil)                                        CSI enclosre % RH sensor                                        SR-50 ultrasonic snow/water level sensor                                                     range, min-0.5 m    19.7 inches                                                     range, max-10 m     393.7 inches                                         Tair corr.?     L(0 degrees CM= L(raw m) *
((Tair+273.15)/273.15)^0.5 (this is supposed to correct for changes in the density of air with temperature)  Apparently sound travels faster in warm air, yielding underestimates of distance with this sensor unless  the correction is applied Using CSI equation for temperature correction:                       5        100.9    %                    25      104.5    %   3.6 % Temperature error is about 9% over seasonal range of air temperatures (-20C to + 30 C)                                      equiv to error of     0.053 m from coldest to warmest                    0.003 m per degree C (approx)                                                                               equiv to error of          2.1 inches from coldest to warmest                   0.11 inches per degree C (approx)
But regressing baseline level changes to air temperature suggests that this equation gives 10x too strong a response and                                                             inappropriate Alternative baseline correction:  the daily pattern of variation best matches the rate of change of soil T Battery voltage was rather well correlated with daily changes in baseline, but this was apparently because solar charging of                                                             the battery covaries with solar heating of the ground. After making a linear correction for this (slope = 0.0181 and                                                                         r2=13%) no other measured factor correlates with the residual variation. This correction removes mid-day peaks in the                                                                 baseline but only reduces the residual baseline variation 13% for the month. The residual baseline variation (range, +/- 1.2                                                             cm) is probably caused by ground roughness and echo from nearby objects (affected by air conditions.
Field of View    22 degrees estimated r =    0.194 x height = field of view radius         min r =     0.097 m at 0.5 m distance         max r =     1.94 m at 10 m distance         installed height    1.478 m        58.19 inches         installed r =         0.287 m        11.29 inches
Required Maintance: Desiccant should be replaced annually in the transducer housing and the main body of the sensor (see manual for details, the sensor head is removed via 4 countersunk philips screws)