Here are the Plots of the band-averaged Spectral Response Functions for all channels for the Imager and Sounder (using the "new" SRF data released in 1999 - see next entry below). These were made for completeness and to be displayed from the new CIMSS/ASPT Calibration Homepage.
On June 23, 1999 ITT released new spectral response functions for the GOES-10 sounder. The GOES-8 and GOES-10 band 13 spectral responses show that GOES-8 and GOES-10 are still dissimilar and that the new GOES-10 response function is very similar to the original. The updated GOES-10 is now more similar to the GOES-8 band 15 spectral response than it was originally, but it is not as close as it was after the April 2, 1998 version of GOES-10 response functions were released.
Note: GOES-10n refers to the spectral response functions released on April 2, 1998. GOES-10699 refers to the spectral response functions released on June 23, 1999.
These plots shows the mean differences of GOES-10 imager channels 1-5 and the corresponding GOES-10 sounder channels (imager - sounder). The differences are plotted for each hour during a 24-hour period starting around 1600 UTC, March 28, 1998, over the land and ocean . The area and time were selected such that the imager and sounder view the area within approximately one minute.
For visible channel, the earth appears more reflective to imager than to sounder. The difference has little day to day variation over ocean. The peak difference over land, which normally occurs around local noon, may vary from 2% (March 28) to 6% (not shown but is hinted in March 29 data from 12-15 UTC). March 29 is more cloudy (thus higher average albedo) over the land region than March 28. The difference is about 10-15% of the average albedo over land and 20-30% over ocean.
There is no sounder channel that correspond well to imager Channel 2 (near IR, 3.9 micron). Instead, average of sounder channels 17 (4.0 micron) and 18 (3.8 micron) is compared with imager channel 2. The difference is small at night and becomes larger during day, due to differential response of each channel to solar reflection. Similarly, average of sounder channels 11 (7.0 micron) and 12 (6.5 micron) is compared with imager channel 3 (6.7 micron, the water vapor channel).
Finally, the window channels (Ch. 4 of imager vs Ch. 8 of sounder and Ch. 5 of imager vs Ch. 7 of sounder) compare well with each other. The difference is normally within +/- 0.5 degree.
The GOES-8 and GOES-10 brightness temperatures were again compared after the updated spectral response coefficients for the GOES-10 sounder were put in (7 UTC on April 2, 1998). While most of the bands compare very well, some of the differences for shortwave bands (13-15) still seem too large.
The GOES-8/9 and GOES-10 band 13 spectral responses show that GOES-8 and GOES-9 are more similar than either of the GOES-10's. Yet, the updated GOES-10 is now 'in family' for band 15 compared to the other satellites.
Shown are examples of co-located (meractor re-map) GOES Sounder DPI for both GOES-8 and GOES-10 over the south central US.
The return flow of moisture during the day on 2 Apr 1998 (98092) from GA across to E TX and northward to E KS is evident, as the total precipitable water (PW) Derived Product Images (DPI) between 12z and 00z show [G2P80921.GIF, G2P80922.GIF]. Similar comparisons with raob values overplotted [R2P80921.GIF, R2P80922.GIF] also show that the GOES-8 and GOES-10 products are substantially the same in their overlap region. Anticipated de-stabilization across the south central US was rather small as of 00z, as noted by the GOES Sounder lifted index (LI) DPI at that time [G2L80922.GIF, R2L80922.GIF]. The two satellites again appear much more similar than dissimilar. (Convection that first started just after 00z was near the LA/AR line, close to the only region showing LI values in the GOES DPI in the 0 to -4C range, despite extensive obscuring clouds. More convection developed later about 03z along the OK/AR line.)
GOES-10 Cloud top pressures from March 27, 1998 near 13 UTC are compared to GOES-8 are in good agreement. Scatter plots of co-located observations cloud top pressure for one time period is within 1 hPa on the average. Scatter plots of co-located observations effective cloud amount for one time period is within 2% on the average. A further explanation of the scatter diagrams is found in the table.
Special GOES-10 sounder sectors which include space views allow for the noise values to be determined by looking at the scatter of the uniform space. Preliminary indications from March 25 at 18:02 UTC show the GOES-10 noise seems to be the first sounder to to be within spec for all the channels (table).
Channel 12 at 10:02 UTC on March 20 (and 25), 1998 shows a "banding" which correlates to the space looks. This barely noticeable (in only the most sensitive channels) effect is due to the rapidly changing calibration bias between the space looks. It can be seen that the slope of the bias changes sign near 11 UTC by looking at the channel 12 at 10:02 and 12:02 UTC.
Derived products from the GOES-10 sounder are being generated. Channels 13, 14 and 15 were not used for this example.
The GOES visible (band=19) sounder spectral response functions are shown for all three satellites. The same plot for the GOES-/8/9/10 imager spectral response functions for channel 1 (visible).
Channels 13 and 15 of the GOES-10 sounder are too cold (by over 6 degrees), compared to GOES-8 sounder data. This has the effect of making the GOES-10 retrievals too dry (dots). Updating the GOES-10 radiance bias adjustment file helps to midigate this problem (crosses). Now the differences look more like the GOES-8 retrievals and the radiosondes (not shown).
The calculated brightness temperatures for the 18 sounder channels before and after the update for the correct filter temperatures with the GOES-10 sounder spectral response functions (RTTOVS forward model):
Un-corrected for the shift due to filter temperatures WFGIM 1 18 SAT=10 223.57 223.03 239.18 254.51 265.67 282.68 285.59 286.44 260.57 257.65 245.87 231.21 271.91 259.42 236.74 280.77 285.95 286.36 Corrected for the shift due to filter temperatures WFGIM 1 18 SAT=10 223.68 222.84 239.11 254.63 265.13 282.66 285.57 286.44 260.67 257.64 245.80 231.23 273.27 259.61 238.94 280.49 285.92 286.37
Un-corrected for the shift due to filter temperatures
CH WAVENO(CM-1) WAVELEN(MICRON)
1 679.8178711 14.70982265
2 696.1438599 14.36484718
3 712.8988037 14.02723598
4 732.2866211 13.65585518
5 747.8747559 13.37122250
6 790.6661987 12.64756203
7 830.8142090 12.03638554
8 909.5220947 10.99478531
9 1029.512085 9.713338852
10 1340.128662 7.461970329
11 1423.657837 7.024159908
12 1535.478027 6.512629986
13 2189.547852 4.567152977
14 2215.627197 4.513394833
15 2252.250000 4.440004349
16 2420.379395 4.131583691
17 2512.697510 3.979786634
18 2665.164551 3.752113581
Corrected for the shift due to filter temperatures
CH WAVENO(CM-1) WAVELEN(MICRON)
1 679.1133423 14.72508240
2 695.3190918 14.38188648
3 712.7325439 14.03050804
4 731.4750366 13.67100620
5 747.4318848 13.37914562
6 789.8816528 12.66012478
7 830.2354736 12.04477596
8 908.8108521 11.00338936
9 1028.894897 9.719165802
10 1340.770874 7.458395958
11 1424.113525 7.021912098
12 1535.095459 6.514252663
13 2187.515381 4.571396351
14 2211.469238 4.521880627
15 2248.089355 4.448221684
16 2418.688965 4.134471416
17 2511.202881 3.982155323
18 2662.761230 3.755500078
Earlier field experiments with GOES-8 sounder showed an un-explained difference for channels 13 and 15 when comparing to the HIS. Preliminary indications show the updated calculated brightness temperatures reduce those differences. Note the 'C's marked on the difference plot between the GOES measurements and the averaged HIS.
LA 7840 7860
area ss yyddd hhmmss lcor ecor lr er zr lsiz esiz z bands
---- ---- ----- ------ ----- ----- -- -- -- ----- ----- - -----
7848 75 98028 172000 5081 10841 10 10 19 156 300 2 123456789ABCDEFG
7849 71 98028 172000 5401 6341 10 10 19 160 292 2 123456789ABCDEFG
LA: Done
GOES-10....
AREASTATY 7848 7848 20 75 200 1 18 LAT,15 25 LON,70 80
Min/Max Lat./Long. = 15.00 25.00, 70.00 80.00
area yyddd hhmmss averageTBB StndDev. N CH SS
7848 98028 172000 215.640869 1.719851 7805 1 75
7848 98028 172000 217.140228 1.180145 7805 2 75
7848 98028 172000 239.865936 1.789296 7805 3 75
7848 98028 172000 255.997070 2.252367 7805 4 75
7848 98028 172000 268.613556 3.509661 7805 5 75
7848 98028 172000 285.314087 4.918376 7805 6 75
7848 98028 172000 288.442963 5.672656 7805 7 75
7848 98028 172000 290.108459 5.775917 7805 8 75
7848 98028 172000 267.637543 4.296698 7805 9 75
7848 98028 172000 267.635925 3.606896 7805 10 75
7848 98028 172000 262.780823 3.905803 7805 11 75
7848 98028 172000 242.073593 3.246333 7805 12 75
7848 98028 172000 272.234711 3.759977 7805 13 75
7848 98028 172000 260.843567 2.548309 7805 14 75
7848 98028 172000 234.507812 1.609572 7805 15 75
7848 98028 172000 286.995544 4.115541 7805 16 75
7848 98028 172000 297.135651 4.605953 7805 17 75
7848 98028 172000 301.907898 4.805789 7805 18 75
-- AREASTAT Done --
STOP
GOES-8....
AREASTATY 7849 7849 20 75 200 1 18 LAT,15 25 LON,70 80
Min/Max Lat./Long. = 15.00 25.00, 70.00 80.00
area yyddd hhmmss averageTBB StndDev. N CH SS
7849 98028 172000 213.595993 1.346970 10288 1 71
7849 98028 172000 216.229050 1.036191 10288 2 71
7849 98028 172000 240.803711 1.446372 10288 3 71
7849 98028 172000 259.261169 2.213167 10288 4 71
7849 98028 172000 269.354767 2.878719 10288 5 71
7849 98028 172000 286.827148 4.937650 10288 6 71
7849 98028 172000 289.975159 5.646367 10288 7 71
7849 98028 172000 291.411682 5.971783 10288 8 71
7849 98028 172000 271.901123 4.551138 10288 9 71
7849 98028 172000 269.397491 3.381033 10288 10 71
7849 98028 172000 264.993500 4.015846 10288 11 71
7849 98028 172000 245.290222 2.863240 10288 12 71
7849 98028 172000 281.580963 4.380967 10288 13 71
7849 98028 172000 268.324371 2.998654 10288 14 71
7849 98028 172000 244.256439 1.953310 10288 15 71
7849 98028 172000 289.403198 4.248234 10288 16 71
7849 98028 172000 298.493896 4.426011 10288 17 71
7849 98028 172000 303.628387 5.490553 10288 18 71
-- AREASTAT Done --
Average Differences.... (G8-G10)
AVG Diff= -2.0449 1
AVG Diff= -.9112 2
AVG Diff= .9378 3
AVG Diff= 3.2641 4
AVG Diff= .7412 5
AVG Diff= 1.5131 6
AVG Diff= 1.5322 7
AVG Diff= 1.3032 8
AVG Diff= 4.2636 9
AVG Diff= 1.7616 10
AVG Diff= 2.2127 11
AVG Diff= 3.2166 12
AVG Diff= 9.3463 13
AVG Diff= 7.4808 14
AVG Diff= 9.7486 15
AVG Diff= 2.4077 16
AVG Diff= 1.3583 17
AVG Diff= 1.7205 18
At one spot (20N, 75W):
GOES-10...
GIMD IAR,7848 AUTO,1
time, dwell, step, dect, sat: 173048 1 0 2 10
NRDG DRDG MODE MAXE MINE PRIM SECN PCWT PCU
0 0 3 13 0 7 1 50 0
LINE ELEM LAT LON LZEN SZEN ELEV SURF VIS
5811 11791 1998 7502 4280 3886 91 7 46
CHAN1 CHAN2 CHAN3 CHAN4 CHAN5 CHAN6 CHAN7 CHAN8 CHAN9
21578 21643 24101 25572 26721 28141 28292 28302 26219
CHA10 CHA11 CHA12 CHA13 CHA14 CHA15 CHA16 CHA17 CHA18
26887 26514 24495 26875 25927 23386 28195 29335 30359
GOES-8...
GIMD IAR,7849 AUTO,1
time, dwell, step, dect, sat: 172958 1 0 2 8
NRDG DRDG MODE MAXE MINE PRIM SECN PCWT PCU
0 0 3 13 0 7 1 50 0
LINE ELEM LAT LON LZEN SZEN ELEV SURF VIS
6097 8602 1998 7502 2309 3884 91 7 13
CHAN1 CHAN2 CHAN3 CHAN4 CHAN5 CHAN6 CHAN7 CHAN8 CHAN9
21604 21704 24236 25929 26920 28495 28782 28998 27179
CHA10 CHA11 CHA12 CHA13 CHA14 CHA15 CHA16 CHA17 CHA18
26902 26509 24706 28242 26811 24556 29183 30409 31206
The calculated brightness temperatures for the 18 sounder channels: WFGIMNTX 1 18 SAT=8 223.55 222.93 238.60 254.44 265.28 282.62 285.57 286.41 260.66 257.55 246.19 231.40 275.07 261.13 239.72 280.92 285.88 286.33 WFGIMNTX 1 18 SAT=9 223.44 222.60 237.93 254.37 264.41 282.63 285.54 286.44 260.72 257.83 246.28 231.48 275.63 261.34 240.48 279.88 285.92 286.35 WFGIMNTX 1 18 SAT=10 223.57 223.01 239.06 254.49 265.59 282.64 285.59 286.44 260.58 257.67 245.83 231.27 272.07 259.80 236.82 280.77 285.96 286.35