Infrared thermometers and temperature sensors, such as the AGRI-THERM II manufactured by Everest Interscience has been used for several decades now to measure the temperature from surface targets outside the gates. This work has been primarily for agricultural applications to determine optimum irrigation scheduling and keep the water. Another use of infrared thermometers where temperatures are taken out of doors includes sports medicine applications. In many of these applications, it was found that temperatures were lower than what was significant. Any measurement of the infrared temperature is taken outside the gates can be found to have the same problem. An important concept has often been overlooked in these studies. This effect is the sky radiation. One way to compensate for the reflection to the sky from plants or other objects the infrared thermometer is measuring must be employed to ensure accurate readings.
The only solution to the phenomenon of radiation sky is the addition of the Everest Interscience SKY-spy for the infrared thermometer or temperature sensor. The SKY-Spy "… provides a new means to detect level of infrared radiation received by the measure is subject to a skyward direction, "according to U.S. Patent No. 4,420,265 Everest. With this invention, a second detector which uses the reflection of vegetation or the target is received from a skyward direction may be taken into account to measure the surface temperature real goal. The purpose of this second sensor is to account for the characteristics of reflected sky radiation and compensate the temperature reading of the goal itself, to produce a more accurate measurement of infrared.
To explain the inaccuracies that can be obtained by taking off the doors of infrared temperature measurements without the use of a sky-Spy, assume that the object being measured is a mirror of the first surface and the temperature is reflected in the mirror is the temperature of the radiation from the sky. This temperature could be up to -80 ° C in clear sky conditions. Then suppose that the mirror effect is fading on the object and the mirror radiation represents only 2.0% of total radiation (surface emissivity = 0.98) and objective forms 98%. Radiation secondary mirror, or the temperature of the sky radiation reflected by the secondary mirror is now only two (2.0) percent of the radiation or temperature of -1.6 ° C. The temperature of a leaf or is generally in the range of not more than ten degrees lower compared to the surrounding ambient air. Thus -1.6 ° C could be sixteen (16) percent of the total or a maximum of -1.6 ° C, so that the effective temperature of the target by that amount. In a science where the infrared temperature measurement precision is critical, this error is intolerable.
Of course, in low elevation, perhaps in the presence of water vapor and the upper layers of CO2, the apparent temperature of the sky is much warmer than -80 ° C. Under these conditions, the sky-SPY immediately and automatically corrects for all sky temperatures from ambient to -100 ° C or more.
This SES-SPY, along with infrared thermometers for temperature measurements infrared to an accuracy of ± 0.5 ° C which is discussed in U.S. Patent Everest No. 4,301,682, provide a means of making more precise measurements of temperature exact necessary for applications in agronomy. These include Everest AGRI-THERM II infrared thermometer handheld, and its model of its new model 4000 and modules 3800ZL Fixed infrared temperature sensors.
The AGRI-THERM II has been widely used worldwide to measure crop canopy temperature in a attempt to control irrigation, with the aim of improving crop yields and reduce the amount of water needed. More information about this topic can be read in the book MB Kirkham, Principles of Soil and Plant Water Relations, 2004.
The AGRI-THERM II infrared thermometers are capable of taking action surface temperature in a highly dynamic environment like the thermometer that takes a truck with air conditioning in the heat of the desert, without giving them time to balance before taking measurements. In these environmental conditions, they respond with accuracy of ± 0.5 ° C or ± 1.0 degrees F.
Everest also markets infrared sensors, the Model Model 4000.4ZL and 3800ZL, infrared sensors that can be mounted in the field and run continuously.
If you are planning to attend the Joint Meeting of the Geological Society of America, Society of Soil Science of America, the American Society of Agronomy and the Crop Science Society of America in the R. George Brown Convention Center in Houston, Texas, on October 5 to October 8, please stop by Booth # 1121 to learn more about the sky-spy.
M113 Gavin Visual, Infared and Radar Camouflage by Saab
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