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Meteorological Instrumentation

SERC collects weather data to complement its collection of ultraviolet data. You can access
real time readings from various instruments that are located on top of a 120 foot tower, located at 38.89 N 76.56 W ( NAD27 ), adjacent to the Mathias laboratory. The data are stored in computer files for long term reference. The archived weather data are available for query and download.

Global ( total hemispherical ) solar flux is measured with a pyranometer. SERC-SRL uses an Eppley model PSP precision spectral pyranometer to measure radiation from 285 to 2800 nanometers. This thermopile-type instrument produces a voltage linearly proportional to the irradiance reaching the detector. The PSP is connected to a data logger by shielded twisted pair copper wires. The reported one minute data is the average of six readings each 10 seconds apart.

Temperature & Relative Humidity are measured with an active probe, a Vaisala model HMP45AC. The probe utilizes a 1000 ohm platinum resistance thermometer as the sensor for ambient temperature. A capacitive polymer sensor is used to sense relative humidity. The reported one minute data value is the average of six readings each 10 seconds apart.

Barometric pressure is measured using a Vaisala PTB 101B series barometric pressure transducer. Data collection is with a CSI CR10X.

Wind speed / wind direction is measured by a R. M. Young 05103 Wind Monitor. Data collection is with a CSI CR10X.

Rainfall is measured minute by minute using a TE525 "Tipping Bucket" rain gauge with a resolution of 0.01 inches. Data collection is with a CSI CR10X.