Vaisala PTB210 SERIES Manuel d'instructions télécharger pdf (Page 92)

BGC-FTIR | Introduction 7

1.1 Introduction

Measurements with the MPI-BGC FTIR system are only possible when the

sun is visible. However, the solar tracker which guides the sunlight into the

instrument has to be protected from precipitation and other adverse environ-

mental conditions. Therefore the FTIR system needs a weather station to

determine if the local weather conditions are favourable for measurements or

if the solar tracker should be protected.

Figure 1.1: The BGC-FTIR weather station

The main parameters which will be determined are temperature, humidity,

solar radiation, wind speed and precipitation. To increase the reliability of the

system, all of the crucial parameters are measured redundantly with duplicate

sensors or sensors of diﬀerent principle. The redundant sensor principle is also

useful to correct for long-term drift of the sensors.

Temperature and humidity are measured with two compact meteorological sen-

sors. Wind speed is provided by two cup anemometers with high reliability.

Precipitation is detected by a light barrier and a contact conclusion system.

A pyranometer provides measurements of the global solar radiation. The high

precision pressure measurement is implemented with a digital sensor which

provides maximum accuracy as well as long-term stability. A thermistor and

a digital temperature/humidity sensor are used for monitoring the conditions

inside the BGC-FTIR-Container.

The sensor signals are collected by the Datalogger CR1000 at several analog

and digital inputs. The CR1000 and the sensors form a completely autonomous

system. Communication with the master PC is accomplished over an ethernet

connection with the Ethernet/Compact Flash Module NL115. Data are stored

in tables on the CPU as well as on the CF-Card.

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Vaisala PTB210 SERIES Manuel d'instructions Page 92