![radiometer point measure radiometer point measure](https://www.basic4mcu.com/data/file/k10/thumb-3660040649_JmhLHITd_Signal_Meter_white_plain_V-LARGE_digits_005_600x347.jpg)
(3), with additional terms to compensate for wind-speed dependence of the apparent surface emissivity, can retrieve the SST. A combination of the brightness temperature, such as Eq. The suite of channels is selected to include sensitivity to the parameters interfering with the SST measurements ( Wilheit et al., 1980) such as cloud droplets and surface wind speed, which occurs with microwaves at higher frequencies. Microwave radiometers use a similar measurement principle to infrared radiometers, having several spectral channels to provide the information to correct for extraneous effects, and two-point calibration procedures to ensure the accuracy of the measurements. Minnett, in Encyclopedia of Ocean Sciences (Third Edition), 2019 Microwave Measurements First, the data was received by the meteorological operations control center (MetOCC) then, the user-formatted output tape from MetOCC is transferred to and processed by the science and applications computer center (SaCC) and finally, SaCC derives the required geophysical parameters from the radiometric data.
![radiometer point measure radiometer point measure](https://i1.rgstatic.net/publication/4183749_Baseline_calibration_of_interferometric_radiometers_Experimental_results/links/02e7e52f286d39dc08000000/largepreview.png)
The processed data stream of SMMR was divided into three categories. The purpose of SMMR is to serve ocean circulation parameters such as sea surface temperatures, low altitude winds, water vapor and cloud liquid water content, sea ice extent, sea ice concentration, snow cover, snow moisture, soil moisture, rainfall rates, and differentiation of ice types. Johnston shaped the design and accomplished the fabrication of SMMR at the Jet Propulsion Laboratory. This idea come from the experience gained by a wide variety of experiments carried out in the laboratory, in the field, and onboard air and spacecraft using microwave radiometers over a wide wavelength range. Richter at Goddard Space Flight Center came up with the idea of developing SMMR. This provides a 780 km swath of the Earth’s surface. A parabolic antenna of SMMR is 79 cm in diameter and maintains a constant nadir angle of 42 degrees, resulting in an incidence angle of 50.3 degrees at Earth’s surface. The spatial resolution is 25 km for all channels that is, 6.6, 10.7, 18, 21, and 37 GHz. It was a 10-channel instrument that receives electromagnetic waves on both horizontally and vertically polarized radiation. (2009), it was the first microwave instrument operated for long duration and within adequate wavelengths. The SMMR onboard NASA’s Nimbus-7 Pathfinder satellite provided service from Octoto August 20, 1987. Islam, in Satellite Soil Moisture Retrieval, 2016 3.1 The Scanning Multichannel Microwave Radiometer (SMMR)