NASA SIR-C Data
SIR-C Radar Modes
The SIR-C radar has various modes of operation which are different combinations of frequency and polarization (see Table below). Modes 1 through 16 were the primary modes of operation; most of the repeat-pass interferometry data collected during the last three days of SRL-2 were collected in Mode 20. Different modes were used for each datatake depending on the primary science goal of the datatake. For example, geology datatakes were often taken in Mode 11 which provides dual frequency and dual polarization data and a swath width of approximately 30-50 km thereby providing good data coverage. Ecology datatakes were often taken in mode 16 which is dual frequency and quad polarization; due to the greater amount of data collected in mode 16, the swath width is narrower and is typically 10-25 km wide. Many sites were imaged in more than one mode on different data passes. The mode information for each datatake is included in a text file posted with the survey data for each datatake. This text file, called DTHDR.TXT has the mode information on line #6.
The columns headed by "channel 1", "channel 2", etc., indicate the data recorded to each of four high density digital recorders on-board the Space Shuttle during mission operations. Therefore, to find out which frequencies and polarizations were recorded for a particular mode, just look up all the frequencies and modes saved to the four recorder channels. In order to double the swath, the same frequency and polarization was saved to more than one channel.
The frequency and polarizations letter abbreviations indicate the following :
|Mode||Channel 1||Channel 2||Channel 3||Channel 4||Notes|
|3||CHH||CHH||CHV||CHV||Double swath, APL receives CH|
|7||LHH||LHH||CVV||CVV||Double swath, APL receives CH|
|10||LVH||LVH||CVH||CVH||Double swath, APL receives CV|
|17||LHH||LHH||LVV||LVV||Normal swath, 40 MHz experimental mode|
|18||CHH||CHH||CVV||CVV||Normal swath, 40 MHz experimental mode|
|19||LHH||LHH||CHH||CHH||Normal swath, 40 MHz experimental mode|
|20||LVV||LVV||CVV||CVV||Normal swath, 40 MHz experimental mode|
|21||LVH||LVV||CVV||CVV||Normal swath, interferometry mode|
|22||CVV||CVV||CVV||CVV||Double swath, interferometry mode|