COMETEO Professional Thermometer Screen for Weather Station Sensor

Professional radiation shield for protection of temperature sensors or combined temperature/humidity sensors, weather monitor and datalogger. Passive, naturally ventilated.

"Not only thermometer screen, but the complete COMETEO system minimizing measurement errors when used with high-quality certified sensors"

Multi-plate radiation shield is used to protect weather monitor systems and provides the most accurate climate measurement results. The uniquely designed screen minimizes solar radiation reaching the sensor, minimizes radiation absorbed by the screen and maximizes ambient air flow around the weather station sensor. The surface exposed to sunlight is made of highly reflective UV and long-term stable ASA plastic. The inner surfaces of the screen are made of matt black plastic to minimize internal reflections. Large 210mm diameter of 14 plates is designed to provide full protection of weather sensor.

Each of the fourteen black louvres is equipped with a circular slot allowing air to flow vertically through the entire radiation shield. The slot also separates the sunlit part of the louvre from the inner part and thus prevents heat transfer to the sensors.

Cylindrical space with 110mm diameter and 210mm height is available inside of the plates for installation of entire climate measuring device with minimized solar radiation.

Excellent wasp and bug deterrence. Sophisticated design prevents insects from building nests inside and thus degrading measurement.

Low cost stable replacement for Stevenson screen, taking advantage of reduced maintenance and better performance due to the low time constant compared to the traditional Stevenson screen.

Works with COMET instruments and most professional weather equipment.

code

F8000

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Product variants

Technical data

GENERAL TECHNICAL DATA

Temperature operating range -40 to +65 °C

Relative humidity operating range 0 to 100 %RH

Storage temperature range -40 to +65 °C

Storage relative humidity range 0 to 100 %RH (no condensation)

Dimension 250 mm (diameter), 396 mm (height)

Dimensions of internal space 110 mm (diameter), 210 mm (height)

Weight approximately 2.4 kg (without mounting clamps)

Material UV stabilized ASA, stainless steel

Warranty 3 years

WIRED Compatible COMET transmitters

Measured Value / Output	4-20mA	0-10V	RS232	RS485	Ethernet / PoE
Temperature	P0120	P0210	T0310	T0410	T4611 * SN200
Temperature + Relative Humidity	T3110	T0210	T3311	T3411	T3611 *
Temperature + Relative Humidity + Atmospheric Pressure	-	-	T7310	T7410	T7611 *

* Probe itself inside of the meteoshield, electronic device outside of the meteoshield in a separate watertight case

WIRELESS Compatible COMET Products

Measured Value / Output	Sigfox IoT	WiFi WLAN	GSM / GPRS
Temperature	W0810 W0832	W0711 * SN200C	U0110G
Temperature + Relative Humidity	W3810	W3711 * DIGIL/E-2	U3121G * DIGIL/E-2
Temperature + Relative Humidity + Atmospheric Pressure	W7810	-	-

* Probe itself inside of the meteoshield, electronic device outside of the meteoshield in a separate watertight case

Air Temperature in Meteorology

The measurement of air temperature in meteorology is a difficult task. Accurate air temperature measurements require minimization of local effects (e.g. trees and buildings) and minimization of environmental effects that influence the actual sensing of the temperature at the position of the sensor. World Meteorological Organization - WMO defines internationally the temperature of the air nearby the earth's surface as “the temperature indicated by a thermometer exposed to the air in a place sheltered from direct solar radiation” (WMO, 1992).

The main functions of thermometer shields are to protect the sensor from direct or indirect radiation from the sun during the day and from radiation from the sensor to the sky at night and to protect the sensor from wetting. Wetting of the sensor and screen is caused by fog, drizzle or rain. But protection against radiation and wetting conflicts with the requirement of sufficient ventilation. Due to insufficient ventilation a microclimate develops within the screen. In fact, all screens develop their own microclimate and the difference with the ambient climate depends on screen type and design. It may be stated that the larger the bulk of a screen, the stronger the microclimate within the screen and the more the sensed temperature deviates from the real air temperature. From the above, it follows that thermometer screens should have a high reflectivity to minimize heating of the plates and subsequent warming of the air as it flows over the plates to the sensor. To decrease the time the air is in contact with the plate, the plate radial distance should be as small as possible. To prevent the development of microclimates within screens, also the blockage of ambient airflow by the screen should be minimized by making the plate spacing as large as possible, taking into account the requirement that wetting of the sensor should be prevented. Any design of a thermometer screen is a result of compromises. Finding the optimal design is a serious challenge that may require the use of different methods for studying the behavior of screens. In the field, the actual differences between the air temperature in the screens and the ambient air temperature depend mainly on the prevailing weather conditions. Furthermore, the state of the ground and humidity of the soil will also affect the air temperature in the screen as radiation or reflection will cause screen dependent biases. This can easily occur in areas with snow cover and in deserts.

Applications:

Meteorology - COMET sensors together with COMET radiation shields are the ideal basis for weather stations for long-term weather, climate and air monitoring.

Snow Guns

Building management - Our instruments which measure temperature, humidity, atmospheric pressure and CO2 are an integral part of these industry-leading solutions.

Reference

Intercomparison of Thermometer Screens in the Arctic

Type of application: Weather monitoring

COMET measures in Antarctica

Type of application: Industry Healthcare and Laboratory Server rooms and data centers Agriculture Weather monitoring