| DQR ID | Subject | Data Streams Affected |
|---|---|---|
| D050714.4 | SGP/MMCR/C1 - Poor cross polar isolation | sgpmmcrmomC1.b1 |
| D100729.1 | SGP/WACR/C1 - Reflectivity and Height Offsets | sgpwacrC1.b1, sgpwacrspeccmaskxpolC1.a0, sgpwacrspeccmaskcopolC1.a0 |
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 08/15/2004 | 0000 | 08/27/2010 | 2100 |
| Subject: | SGP/MMCR/C1 - Poor cross polar isolation |
| DataStreams: | sgpmmcrmomC1.b1 |
| Description: | This last spring, Sergey Matrosov pointed out that the Circular Depolarization Ratio measurements on the SGP radar indicated the isolation between the co and cross channels was only about 15 dB. Typically isolation of 25-30 dB is expected for polarization measurements to be useful. We set about to see if we could identify the source of the poor isolation. Kevin Widener had purchased a custom built orthomode transducer and polarizer that hadn't gone through any previous testing and we decided to swap it out with an ETL unit that had shown good isolation in the past. Kevin performed the swap a couple of weeks back and this week the latest archive data was available to compare results between the OMTs. Results from two precipitating cloud conditions, where we looked below the melting layer, where we expect to find domination of spherical water droplets and therefore maximum values for cdr - the maximum isolation (CDR) appears to be about 17 dB. The results showed that the poor isolation is probably not due to the OMTs but rather to the antenna itself. |
| Measurements: | sgpmmcrmomC1.b1:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 12/05/2005 | 0000 | 09/23/2008 | 2359 |
| Subject: | SGP/WACR/C1 - Reflectivity and Height Offsets |
| DataStreams: | sgpwacrC1.b1, sgpwacrspeccmaskxpolC1.a0, sgpwacrspeccmaskcopolC1.a0 |
| Description: | The instrument vendor has informed us of a range (height) offset of 13 m and has provided an updated reflectivity calibration. All values reported for 'Reflectivity' are approximately 3 dB too low. In addition, the Reflectivity in the first and fourth range gates (starting from the surface) need to be further corrected by an additional 2.7 and -0.9 dB, respectively. The 'height' field values are 13.33 m too low. The data will be reprocessed to correct these problems. Update: The sgpwacrC1.b1 data were reprocessed to correct the height and reflectivity offsets. The corrected data were archived 20100910-20100915. |
| Measurements: | sgpwacrspeccmaskcopolC1.a0:
sgpwacrspeccmaskxpolC1.a0:
sgpwacrC1.b1:
|