1x1 degree grid

[jsodhi]

Hi,

I would like to know is there a way to get the output at 1x1 degree resolution using convert_mpas
example lat: -90, -89, -88, ... ,90
              lon: 0, 1, 2, 3, .. , 359
where,
    nlat=181
    nlon=360

For mpas_to_latlon.ncl, when I'm trying to convert vorticity to regular lat-lon grid the following error is displayed while calculating weights (mesh = 40962)


(0)    nTime   = 1
(0)    nCells  = 81920
(0)    nLevels = 41
(0)             
fatal:(nCells) is not a dimension name in variable (mpas), could not determine dimension number
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 68 in file mpas_to_latlon.ncl

It seems to be fine when using fields qv, pressure.

regards,
jsodhi

[MPAS-Atmosphere Help]

Hi, Jsodhi.

I haven't used the 'mpas_to_latlon.ncl' script in a while, but from what I can recall, it only works for cell-based fields (like qv and pressure). The vorticity field is located on cell corner points (vertices), and so the script may not be able to handle this field without some modifications.

For the convert_mpas program, you can create a text file named 'target_domain' in your working directory with the following lines:

nlat=181

startlat=-90.5

endlat=90.5

nlon=360

startlon=-0.5

endlon=359.5

to get a 1x1-degree lat-lon mesh with points at latitudes -90, -89, ..., 89, 90 and longitudes 0, 1, ..., 358, 359.

Best regards,

Michael

[jsodhi]

Hi Micheal,

Please have a look on this

#########################################################
lat = -90, -89, -88, -87, -85.99999, -84.99999, -84, -83, -81.99999,
    -80.99999, -80, -79, -78, -77, -75.99999, -75, -74, -73, -72, -71, -70,
    -68.99999, -68, -67, -66, -65, -64, -63, -62, -61, -60, -59, -58, -57,
    -56, -55, -54, -53, -52, -51, -50, -49, -48, -47, -46, -45, -44, -43,
    -42, -41, -40, -39, -38, -37, -36, -35, -34, -33, -32, -31, -30, -29,
    -28, -27, -26, -25, -24, -23, -22, -21, -20, -19, -18, -17, -16, -15,
    -14, -13, -12, -11, -10, -9, -8, -7, -6, -5, -4, -3, -2, -0.9999999, 0,
    0.9999999, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
    19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
    37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54,
    55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 68.99999, 70, 71,
    72, 73, 74, 75, 75.99999, 77, 78, 79, 80, 80.99999, 81.99999, 83, 84,
    84.99999, 85.99999, 87, 88, 89, 90 ;

 lon = 0, 0.9999999, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
    18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
    36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
    54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 68.99999, 70,
    71, 72, 73, 74, 75, 75.99999, 77, 78, 79, 80, 80.99999, 81.99999, 83, 84,
    84.99999, 85.99999, 87, 88, 89, 90, 91, 91.99999, 92.99999, 94, 95, 96,
    97, 98, 98.99999, 99.99999, 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, 201, 202, 203, 204, 205, 206, 207,
    208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221,
    222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235,
    236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249,
    250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263,
    264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277,
    278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291,
    292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305,
    306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319,
    320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333,
    334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347,
    348, 349, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359
############################################################
Can you explain why this happens?

regards,
jsodhi

[MPAS-Atmosphere Help]

Hi, Jsodhi.

Internally the convert_mpas program uses all latitudes and longitudes in radians. The *.99999 values look like the result of converting the latitude and longitude values specified in the 'target_domain' file from degrees to radians, then converting the 'lat' and 'lon' arrays from radians back to degrees before writing them to the output file. If you'd like to modify the computation of these arrays, you can check out the code in the target_mesh_setup( ) routine in target_mesh.F and in the remap_get_target_{latitudes,longitudes}( ) routines in remapper.F.

Best regards,

Michael