High Level (Cirriform) Frequency of Occurrence (%) March (1954 - 1997) Day, Ship Observations Only Global Average: 39.4 Zonal Averages 17 zones Lat.N Average 85 63.0 75 45.8 65 38.2 55 36.9 45 37.9 35 38.7 25 32.0 15 30.6 5 44.8 -5 48.7 -15 43.5 -25 37.0 -35 37.0 -45 37.1 -55 38.6 -65 39.7 -75 43.6 Grid Box Averages 371 filled boxes Box # Lat.N Lon.E Average 1 85 60 65.8 2 85 180 63.7 3 85 300 58.1 4 75 20 31.6 5 75 60 24.0 6 75 100 14.1 7 75 140 48.9 8 75 180 62.6 9 75 220 81.9 12 75 340 26.8 13 65 10 37.8 14 65 30 39.1 15 65 50 40.0 21 65 170 23.8 22 65 190 29.8 23 65 210 40.8 29 65 330 49.9 30 65 350 36.4 31 55 10 40.1 32 55 30 28.6 38 55 150 30.9 39 55 170 32.3 40 55 190 33.5 41 55 210 38.9 42 55 230 41.9 46 55 310 36.3 47 55 330 37.9 48 55 350 46.4 49 45 5 45.4 50 45 15 38.7 51 45 25 29.7 52 45 35 26.0 53 45 45 29.7 54 45 55 27.5 62 45 135 25.4 63 45 145 28.8 64 45 155 29.2 65 45 165 33.1 66 45 175 34.7 67 45 185 39.1 68 45 195 40.4 69 45 205 42.3 70 45 215 42.6 71 45 225 43.1 72 45 235 46.0 77 45 285 34.5 78 45 295 36.1 79 45 305 39.0 80 45 315 40.2 81 45 325 40.3 82 45 335 40.6 83 45 345 39.0 84 45 355 40.0 85 35 5 40.5 86 35 15 34.4 87 35 25 30.8 88 35 35 30.7 89 35 45 22.0 90 35 55 32.2 96 35 115 24.0 97 35 125 29.6 98 35 135 34.9 99 35 145 33.4 100 35 155 33.9 101 35 165 36.6 102 35 175 39.5 103 35 185 42.8 104 35 195 41.3 105 35 205 44.4 106 35 215 43.0 107 35 225 41.5 108 35 235 38.4 109 35 245 37.2 112 35 275 45.7 113 35 285 39.3 114 35 295 36.5 115 35 305 39.5 116 35 315 43.4 117 35 325 44.1 118 35 335 41.4 119 35 345 36.2 120 35 355 40.8 124 25 35 26.5 125 25 45 32.4 126 25 55 31.8 127 25 65 25.5 128 25 75 13.4 129 25 85 26.0 130 25 95 63.1 131 25 105 42.8 132 25 115 28.8 133 25 125 26.5 134 25 135 26.7 135 25 145 26.9 136 25 155 26.5 137 25 165 28.0 138 25 175 28.7 139 25 185 28.6 140 25 195 29.7 141 25 205 32.6 142 25 215 38.3 143 25 225 41.9 144 25 235 42.8 145 25 245 41.3 146 25 255 45.9 147 25 265 44.8 148 25 275 38.4 149 25 285 32.2 150 25 295 28.5 151 25 305 29.6 152 25 315 32.2 153 25 325 30.6 154 25 335 27.6 155 25 345 26.8 160 15 35 22.4 161 15 45 20.8 162 15 55 17.0 163 15 65 17.4 164 15 75 21.7 165 15 85 26.7 166 15 95 30.9 167 15 105 32.8 168 15 115 31.9 169 15 125 34.1 170 15 135 35.8 171 15 145 38.2 172 15 155 33.3 173 15 165 30.1 174 15 175 24.3 175 15 185 25.3 176 15 195 27.0 177 15 205 31.4 178 15 215 38.8 179 15 225 42.3 180 15 235 40.4 181 15 245 37.5 182 15 255 35.0 183 15 265 29.7 184 15 275 31.8 185 15 285 28.9 186 15 295 25.5 187 15 305 27.4 188 15 315 28.4 189 15 325 29.9 190 15 335 29.9 191 15 345 30.4 193 5 5 47.8 197 5 45 27.3 198 5 55 24.4 199 5 65 24.4 200 5 75 36.3 201 5 85 52.8 202 5 95 63.5 203 5 105 53.5 204 5 115 52.7 205 5 125 57.5 206 5 135 63.0 207 5 145 61.5 208 5 155 63.9 209 5 165 54.6 210 5 175 55.4 211 5 185 43.0 212 5 195 41.1 213 5 205 44.4 214 5 215 40.6 215 5 225 38.4 216 5 235 38.5 217 5 245 38.4 218 5 255 29.3 219 5 265 38.3 220 5 275 45.1 221 5 285 45.5 223 5 305 40.6 224 5 315 44.3 225 5 325 44.5 226 5 335 35.3 227 5 345 37.8 228 5 355 48.5 229 -5 5 44.9 230 -5 15 45.7 232 -5 35 64.1 233 -5 45 41.2 234 -5 55 43.5 235 -5 65 46.5 236 -5 75 53.3 237 -5 85 62.9 238 -5 95 67.3 239 -5 105 70.4 240 -5 115 70.2 241 -5 125 67.9 242 -5 135 69.5 243 -5 145 72.7 244 -5 155 69.7 245 -5 165 62.8 246 -5 175 63.5 247 -5 185 55.0 248 -5 195 49.4 249 -5 205 39.9 250 -5 215 42.1 251 -5 225 35.6 252 -5 235 33.1 253 -5 245 31.2 254 -5 255 28.7 255 -5 265 32.5 256 -5 275 45.4 257 -5 285 52.1 260 -5 315 59.3 261 -5 325 52.1 262 -5 335 39.9 263 -5 345 29.6 264 -5 355 32.4 265 -15 5 24.1 266 -15 15 37.1 268 -15 35 41.2 269 -15 45 56.3 270 -15 55 49.9 271 -15 65 50.3 272 -15 75 48.0 273 -15 85 46.7 274 -15 95 48.0 275 -15 105 43.2 276 -15 115 41.1 277 -15 125 51.7 278 -15 135 67.5 279 -15 145 57.6 280 -15 155 55.4 281 -15 165 58.8 282 -15 175 60.1 283 -15 185 61.6 284 -15 195 57.0 285 -15 205 54.3 286 -15 215 51.1 287 -15 225 40.3 288 -15 235 37.3 289 -15 245 31.6 290 -15 255 28.0 291 -15 265 20.6 292 -15 275 29.6 293 -15 285 47.2 297 -15 325 45.8 298 -15 335 31.1 299 -15 345 21.3 300 -15 355 23.9 301 -25 5 15.1 302 -25 15 15.5 304 -25 35 31.5 305 -25 45 35.4 306 -25 55 46.5 307 -25 65 34.0 308 -25 75 35.1 309 -25 85 32.2 310 -25 95 31.1 311 -25 105 28.4 312 -25 115 28.7 315 -25 145 39.7 316 -25 155 35.7 317 -25 165 35.9 318 -25 175 44.6 319 -25 185 49.7 320 -25 195 50.7 321 -25 205 51.3 322 -25 215 56.8 323 -25 225 51.4 324 -25 235 42.6 325 -25 245 41.8 326 -25 255 36.7 327 -25 265 30.5 328 -25 275 18.4 329 -25 285 22.8 332 -25 315 47.2 333 -25 325 46.9 334 -25 335 43.6 335 -25 345 30.7 336 -25 355 25.2 337 -35 5 30.7 338 -35 15 22.4 339 -35 25 30.7 340 -35 35 31.8 341 -35 45 34.4 342 -35 55 38.0 343 -35 65 41.1 344 -35 75 37.4 345 -35 85 36.0 346 -35 95 35.9 347 -35 105 30.7 348 -35 115 34.1 349 -35 125 37.3 350 -35 135 35.8 351 -35 145 37.4 352 -35 155 35.5 353 -35 165 34.5 354 -35 175 38.5 355 -35 185 39.1 356 -35 195 41.4 357 -35 205 40.1 358 -35 215 47.3 359 -35 225 50.4 360 -35 235 52.8 361 -35 245 43.5 362 -35 255 39.0 363 -35 265 26.4 364 -35 275 24.5 365 -35 285 25.5 367 -35 305 31.7 368 -35 315 34.8 369 -35 325 41.4 370 -35 335 41.7 371 -35 345 42.4 372 -35 355 39.6 373 -45 5 35.3 374 -45 15 38.5 375 -45 25 32.5 376 -45 35 39.4 377 -45 45 36.5 378 -45 55 30.1 379 -45 65 35.2 380 -45 75 38.5 381 -45 85 41.0 382 -45 95 31.4 383 -45 105 34.6 384 -45 115 35.3 385 -45 125 37.6 386 -45 135 38.9 387 -45 145 40.0 388 -45 155 41.0 389 -45 165 36.0 390 -45 175 42.8 391 -45 185 40.2 392 -45 195 42.0 393 -45 205 36.1 394 -45 215 35.5 395 -45 225 48.9 396 -45 235 35.8 399 -45 265 38.3 400 -45 275 23.2 401 -45 285 29.7 402 -45 295 39.4 403 -45 305 39.4 404 -45 315 36.9 405 -45 325 42.0 406 -45 335 32.4 409 -55 10 45.3 410 -55 30 36.9 411 -55 50 25.7 412 -55 70 33.6 413 -55 90 41.9 415 -55 130 42.5 416 -55 150 30.2 417 -55 170 26.1 418 -55 190 41.7 419 -55 210 35.8 422 -55 270 52.2 423 -55 290 51.1 424 -55 310 47.5 425 -55 330 35.9 426 -55 350 35.4 427 -65 10 44.6 428 -65 30 47.6 429 -65 50 36.5 430 -65 70 29.5 431 -65 90 37.5 432 -65 110 39.9 433 -65 130 33.3 434 -65 150 38.0 435 -65 170 39.0 441 -65 290 61.2 442 -65 310 31.5 444 -65 350 34.8 449 -75 180 31.6 450 -75 220 54.7 453 -75 340 48.2