1. CoSMIR Performance during OLYMPEX
Rachael Kroodsma
UMD ESSIC / NASA GSFC
OLYMPEX Workshop - Seattle, WA
March 21-23, 2017
Kroodsma OLYMPEX Workshop

2. Kroodsma OLYMPEX Workshop
Outline
Brief CoSMIR description
Instrument characteristics
Improvements since IPHEX
Performance during OLYMPEX
Data outages
Issues encountered
Data Analysis
Geolocation
Comparisons with GMI
Data Description
Kroodsma OLYMPEX Workshop

3. Instrument Characteristics
Conical and cross-track scanning total power radiometer
Off-nadir angle 49.2°
Similar channels as GMI (high frequency)
Frequency (GHz)
50.3
52.8
89.0
165.5
183.31±1
183.31±3
183.31±7
Polarization H
V/H
Sensitivity (K)
0.42
0.40/0.30
0.80/0.45
0.53
0.43
0.41
Scan Geometry
Conical scan
Footprint 1.3x1.9 km*
Azimuth -60° to 60° (51 samples)
3 seconds to complete scan
Cross track scan
Footprint 0.8x0.8 km at nadir*
Elevation -49.2° to 49.2° (51 samples)
2 seconds to complete scan
*DC-8 cruising altitude of 11.8 km
Kroodsma OLYMPEX Workshop

4. Scanning Geometry
Two conical and two cross-track scans are alternately performed every cycle with hot and cold target looks after each scan.
Cold
Cold
Scan Direction
Cold
Cold
Conical 2
Hot
Crosstrack 1
Hot
Conical 1
Hot
Hot
Crosstrack 2
Scan Direction
Flight Direction
CoSMIR scan pattern for one complete cycle where the azimuth rotates once and the elevation twice. Corresponding 89V counts shown for a flight.
CoSMIR ground track for one cycle.
Aircraft ground speed 200 m/s and altitude 11.8 km.
Kroodsma OLYMPEX Workshop

5. Improvements since IPHEX
Several modifications were made since the last campaign (IPHEX in 2014) to make CoSMIR more reliable
Power system now has a custom board to improve instrument grounding and reduce noise
Thermal system now uses chip heaters to better control temperature
166 GHz receiver redesigned with newer technology
Mechanical layout redesigned to make it more robust
Instrument tested in thermal chamber prior to flight
Detected issue with motion control and fixed
Kroodsma OLYMPEX Workshop

6. CoSMIR Performance During OLYMPEX
Overall, CoSMIR operated extremely well for most of the campaign
Total data collected: 72 hours, 8 minutes
Total data lost: approx. 4 hours
Nominal operation: all channels operated for entire flight with CoSMIR in hybrid scan mode
Cross-track mode only: first three flights operated only in cross-track until azimuth scan was fixed
Hot target power supply: issues with power supply on plane caused computer outages and gain increases
Some flights lost 52 and/or 50 GHz channels part way
Kroodsma OLYMPEX Workshop

7. CoSMIR data collected (UTC)
Date (UTC)
CoSMIR data collected (UTC)
GPM overpass (UTC)
CoSMIR performance notes
11/5/2015
20:04-22:38 --
Nominal operation
Engineering test flight out of Palmdale, CA
11/12/2015
16:09-22:17
21:16
Cross-track mode only
11/13/2015
13:56-19:29
11/14/2015
17:13-23:17
21:06
11/18/2015
18:29-00:06
11/23/2015
15:57-21:40
11/24/2015
14:40-19:34
18:36
Hot target power supply issue
11/25/2015
17:24-19:15
17:43
Lost 52 GHz channel after 18:20 due to gain increase
12/1/2015
20:59-01:25
Hot target power supply issue Lost 52 GHz channel after 22:43 Lost 50 GHz channel after 00:15
12/3/2015
14:33-16:59
15:22
Hot target power supply issue Lost 52 GHz channel after 16:05
12/4/2015
13:27-17:31
Fixed hot target power supply issue
12/5/2015
14:18-15:38
15:13
Lost 52 GHz channel after 15:08 Lost 50 GHz channel after 15:31 Lost connection with archive computer at 15:38
12/8/2015
14:08-16:33
17:44-19:24
14:11
Lost 52 GHz channel after 14:36. Lost connection with archive computer at 16:33
Rebooted successfully but hot target temperature not recorded for the rest of the flight
12/10/2015
14:58-15:55
16:34-19:18
Lost connection with archive computer at 15:55. Rebooted successfully but hot target temperature not recorded for the rest of the flight
12/12/2015
15:52-21:15
12/13/2015
13:54-18:15
12/18/2015
04:57-07:04
12/19/2015
01:32-03:22
2:54
Kroodsma OLYMPEX Workshop

8. Quicklook Plot Example 12/3/2015
Kroodsma OLYMPEX Workshop

9. Kroodsma OLYMPEX Workshop
Some Pictures
Credit: NASA
NASA DC-8
CoSMIR
CoSMIR mounted on DC-8
Credit: NASA
Onboard operations
12/4/2015 flight paths
Kroodsma OLYMPEX Workshop

10. Kroodsma OLYMPEX Workshop
Geolocation
CoSMIR has an azimuth mounting offset. This offset was estimated and confirmed using Google Earth to plot TBs at coastlines.
11/18 flight
11/25 flight
89H TBs at coastlines look accurate
Kroodsma OLYMPEX Workshop

11. GPM Overpass: Comparisons with GMI
Channel
GMI
89.0 V/H
166.0 V/H
183.31±3 V
183.31±7 V
CoSMIR
165.5 V/H
183.31±3 H
183.31±7 H
EIA (nominal)
52.8
49.2
49.3
Footprint (km)
4.4x7.2
4.1x6.3
3.8x5.8
1.3x1.9
11/25 clear air flight
Kroodsma OLYMPEX Workshop

12. GPM Overpass: Comparisons with GMI
183.31±3
183.31±7
GMI vs. CoSMIR TBs by channel and date. CoSMIR TBs are averaged over a GMI footprint.
Locations of GMI/CoSMIR match-ups
Channel
89V
89H
166V
166H
183.31±3
183.31±7
GMI-CoSMIR mean TB (K)
2.2
-0.5
1.9
1.1
3.8
Kroodsma OLYMPEX Workshop

13. Kroodsma OLYMPEX Workshop
Data Description
olympex_cosmir_YYYYMMDD_conical_v1.hdf5
olympex_cosmir_YYYYMMDD_crosstrack_v1.hdf5
HDF5 files with 3 groups
Aircraft: altitude, heading, latitude, longitude, pitch, roll, speed
Interpolated to CoSMIR pixels
Cosmir: azimuth, elevation, incidence angle, latitude, longitude, TB
Time: year, month, day of month, hour, minute, second, millisecond
Quicklook plots also available
Kroodsma OLYMPEX Workshop