ObsErrorFactorTopoRad

This obsfunction was designed to mimic GSI-Observer method of observation Error Inflation Factor (EIF).

Error Inflation Factor (EIF) as a function of terrain height, channel, and surface-to-space transmittance.

H = surface height [m]

X = surface-to-space transmittance

R = reference height [m]

Infrared:

\(EIF = SQRT \{ 1 / [ 1 - (1 - (R/H)^4 ) * X] \}\) if \(H > R\).

Microwave:

\(EIF = SQRT [ 1 / ( R / H ) ]\) for \(H > R\).

Required input parameters:

sensor

Currently only works for these sensors infrared and microwave.

infrared is used when sensors are IASI, CrIS, AIRS, AVHRR3, SEVIRI and ABI. microwave is used when sensors are AMSUA-A, ATMS and MHS.

channels

Sensor input channels to which observation EIF is applied.

Optional input parameters:

height groups

Optional list of channels and height used to calculate the EIF.

If the optional parmaeter is not listed and empty, default of sensor input channels and reference height of 2000m is used.

channels

list of channels that need the error correction.

height

reference height in meters used to scale the surface height in EIF calculation, for the channels provided.

Output parameters:

Error Inflation Factor (EIF) for each input channel of the input sensor at each location.

Required fields from obs/geoval:

geovals

GeoVaLs/surface_geopotential_height

obsDiag

ObsDiag/transmittances_of_atmosphere_layer

Example configurations:

- filter: BlackList
 filter variables:
 - name: brightnessTemperature
   channels: 1-15
 action:
   name: inflate error
   inflation variable:
     name: ObsFunction/ObsErrorFactorTopoRad
     channels: 1-15
     options:
       sensor: microwave
       channels: 1-15
       height groups:
       - channels: 1-6, 15
       - channels: 7
         height: 4000

In this example, the observation errors of AMSU-A are inflated according to the microwave algorithm. For channels 1-6 and 15, terrain height of 2000 and for channels 7, terrain height of 4000 are used.

obserr_bound_topo:
  name: ObsFunction/ObsErrorFactorTopoRad
  channels: *atms_npp_channels
  options:
    channels: *atms_npp_channels
    sensor: microwave
    height groups:
    - channels: 1-7, 16-22
    - channels: 8
    height: 4000

In this example, the observation errors of ATMS-npp are inflated according to the microwave algorithm. For channels 1-7 and 16-22, terrain height of 2000 and for channels 8, terrain height of 4000 are used.

channels: &cris-fsr_n21_channels 19, 24, 26, 27, 28, 31, 32, 33, 37, 39, 42, 44, 47, 49, 50,
          51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68,
          69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86,
          87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103,
          104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117,
          118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131,
          132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145,
          146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159,
          160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173,
          174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187,
          188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 208,
          211, 216, 224, 234, 236, 238, 239, 242, 246, 248, 255, 264, 266, 268,
          275, 279, 283, 285, 291, 295, 301, 305, 311, 332, 342, 389, 400, 402,
          404, 406, 410, 427, 439, 440, 441, 445, 449, 455, 458, 461, 464, 467,
          470, 473, 475, 482, 486, 487, 490, 493, 496, 499, 501, 503, 505, 511,
          513, 514, 518, 519, 520, 522, 529, 534, 563, 568, 575, 592, 594, 596,
          598, 600, 602, 604, 611, 614, 616, 618, 620, 622, 626, 631, 638, 646,
          648, 652, 659, 673, 675, 678, 684, 688, 694, 700, 707, 710, 713, 714,
          718, 720, 722, 725, 728, 735, 742, 748, 753, 762, 780, 784, 798, 849,
          860, 862, 866, 874, 882, 890, 898, 906, 907, 908, 914, 937, 972, 973,
          978, 980, 981, 988, 995, 998, 1000, 1003, 1008, 1009, 1010, 1014, 1017,
          1018, 1020, 1022, 1024, 1026, 1029, 1030, 1032, 1034, 1037, 1038, 1041,
          1042, 1044, 1046, 1049, 1050, 1053, 1054, 1058, 1060, 1062, 1064, 1066,
          1069, 1076, 1077, 1080, 1086, 1091, 1095, 1101, 1109, 1112, 1121, 1128,
          1133, 1163, 1172, 1187, 1189, 1205, 1211, 1219, 1231, 1245, 1271, 1289,
          1300, 1313, 1316, 1325, 1329, 1346, 1347, 1473, 1474, 1491, 1499, 1553,
          1570, 1596, 1602, 1619, 1624, 1635, 1939, 1940, 1941, 1942, 1943, 1944,
          1945, 1946, 1947, 1948, 1949, 1950, 1951, 1952, 1953, 1954, 1955, 1956,
          1957, 1958, 1959, 1960, 1961, 1962, 1963, 1964, 1965, 1966, 1967, 1968,
          1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980,
          1981, 1982, 1983, 1984, 1985, 1986, 1987, 2119, 2140, 2143, 2147, 2153,
          2158, 2161, 2168, 2171, 2175, 2182

- filter: Perform Action
  filter variables:
  - name: brightnessTemperature
    channels: *cris-fsr_n21_channels
  action:
    name: inflate error
    inflation variable:
      name: ObsFunction/ObsErrorFactorTopoRad
      channels: *cris-fsr_n21_channels
      options:
        channels: *cris-fsr_n21_channels
        sensor: infrared

In this example, the observation errors of cris-fsr_n21 are inflated according to the infrared algorithm. For all the input channels terrain height of 2000 is used.