High Resolution Infrared Radiometer

Fig. 8. Effective radiance curves, equivalent blackbody temperatures. (High resolution infrared radiometers, Nimbus 2, Nimbus 4, and Nimbus 5.)...

Three satellites would give six readings in twenty-four hours. In the very near future we could combine the information from these three satellites with that from the orbiting Nimbus, ERTS, and ATS when these are equipped with ultra-high resolution infrared radiometers. This would give us 8 to 12 readings per twenty-four hours, and would enable us to perform essential statistical processing. The chief dy-... 

Goldberg, 1. L. 1968, A Very High Resolution Infrared Radiometer Experiment for ATS F and G, Goddard Space Flight Center, X-622-68-26, Greenbelt, Md. 

Williamson, E. J. 1970, The Accuracy of the High Resolution Infrared Radiometer on Nimbus II, Goddard Space Flight Center, TN-D-5551, Greenbelt, Md. 

The first chopped radiometer on a stabilized platform, functioning in a line by line scanning pattern perpendicular to the direction of spacecraft motion, was the High Resolution Infrared Radiometer (HRIR) on Nimbus II (1964) shown in Fig. 5.4.10. The purpose of the investigation was to obtain cloud images on the dark hemisphere... 

Fig. 5.4.10 The High Resolution Infrared Radiometer of Nimbus II. The radiative cooler is on the right (Nimbus Project, NASA).

The Advanced-Very-High-Resolution Radiometer (AVHRR) carried on board the NOAA-7 satellite has been collecting radiance data from the earth s surface since 1978. The polar-orbiting satellite records global data on a neardaily basis. The 4-kilometer data have been remapped by NO A A into monthly composites. The data are collected in 2 bands-one visible (VIS), the other near infrared (NIR). The Normalized Difference Vegetation Index, or NDVI, defined... 

This investigation is based on data of the Advanced Very High Resolution Radiometer operated on the weather satellite series of the National Oceanic and Atmospheric Administration of the United States of America. The first instrument was launched in 1978. Three versions of the multichannel scanning radiometer were operated at 13 satellites and measured in 5-6 channels in the visible, near-infrared and thermal infrared spectral range, as defined in Table 9.1. 

Figure 12 is an example of a map set up in this way. It is for a high resolution radiometer operating on the Nimbus 3 satellite in the daytime. Orbit no. 711,6 June, 1969 was selected because of the high quality of reflected infrared, spectral band 0.7-1.3 fim. A routine some months old was used to convert the effective radiation... 

In the far infrared, where signals usually are weak and where detectors may show 1 If noise, operation at frequencies as low as a fraction of a hertz is often not possible for an explanation of 1 // noise see page 264. To raise the low frequency cut-off of such a radiometer is also undesirable. Inadequate reproduction of low frequencies affects mostly the overall signal level (the absolute calibration), while inadequate response at high frequencies affects primarily spatial resolution and sharpness of contours in the images. 

---