L-Band Microwave Experiment on Russian Investigational Satellite, first Results and Comparison with SMOS Data
Smirnov, Mikhail1; Khaldin, Alexander2
1Institute of Radioengineering and Electronics RAS, RUSSIAN FEDERATION; 2Special Design Bureau of the Institute of Radioengineering and Electronics RAS, RUSSIAN FEDERATION
In recent years the high interest in passive microwave L-band measurements from space was raised. Successful launch of SMOS shows the new advantages in Earth investigations from space in this promising band. Now such activity is supported in Russia after launch of experimental passive microwave radiometric system named Zond-PP installed on a new small satellite (MKA) on July 22, 2012. Radiometric system Zond-PP is relatively simple and consists of L-band microwave radiometer with 2 beams antenna. Spatial resolution of instrument is about 350 km and swath width 700 km. Orbit of the satellite has inclination 98.8° and height 820 km.
In the main operational mode two beams of the Zond-PP oriented across the flight direction in order to have declared swath width. In addition to this mode it is possible to rotate the satellite so that two beams will be in a flight plane. This mode may be useful for calibration purposes and development of RFI investigation algorithms. MKA onboard system capabilities are very strict, so measurements performed not continuously, but within special program.
The main scientific objectives of mission with Zond-PP are development of techniques for retrieval: sea salinity in open oceans, soil moisture in global scales, vegetation state characteristics, sea ice characteristics. At the first stage of space experiments the main goals were to develop and test new space microwave radiometric instrument in order to solve the following technical objectives: investigation of RFI situation in L-band all over the globe, development and testing in-flight calibration techniques.
Main goal of this work was to present first obtained results and analyze data quality of our observations. Important part of the work is comparison of RFI impacts with other similar experiments. Quality of data calibration may be estimated by evaluation of measured brightness temperatures over different region by different instruments.
Long time operation of SMOS and similarity of MKA and SMOS orbits allows us to compare their results. For comparison were used results of brightness temperatures measurements obtained from MIRAS and Zond-PP in the same regions and having time difference not more than 12 hour.
Results of comparison show general accordance in the brightness temperatures levels. Influence of RFI differs due to dissimilarity in spatial resolution and instruments design.
SMOS data provided by the European Space Agency