High Level (Cirriform) Frequency of Occurrence (%) September (1954 - 1997) Night, Ship Observations Only Global Average: 26.8 Zonal Averages 15 zones Lat.N Average 85 51.6 75 36.5 65 34.5 55 30.8 45 29.2 35 26.7 25 26.9 15 36.3 5 37.7 -5 25.3 -15 18.4 -25 17.6 -35 20.4 -45 26.2 -55 22.2 Grid Box Averages 307 filled boxes Box # Lat.N Lon.E Average 1 85 60 44.5 2 85 180 52.9 3 85 300 59.5 4 75 20 31.4 5 75 60 26.8 6 75 100 26.2 7 75 140 32.3 8 75 180 41.4 9 75 220 51.6 10 75 260 47.6 11 75 300 34.9 12 75 340 31.1 13 65 10 35.1 14 65 30 32.1 15 65 50 28.6 21 65 170 23.9 22 65 190 34.8 23 65 210 52.3 25 65 250 47.2 26 65 270 41.2 27 65 290 42.4 28 65 310 35.5 29 65 330 32.0 30 65 350 31.2 31 55 10 37.4 32 55 30 31.6 38 55 150 24.5 39 55 170 24.7 40 55 190 36.7 41 55 210 28.6 42 55 230 31.9 44 55 270 54.8 45 55 290 33.7 46 55 310 27.3 47 55 330 27.4 48 55 350 35.0 49 45 5 33.2 50 45 15 24.9 51 45 25 13.8 52 45 35 9.8 54 45 55 11.9 62 45 135 26.1 63 45 145 26.5 64 45 155 30.1 65 45 165 31.7 66 45 175 36.3 67 45 185 38.1 68 45 195 39.0 69 45 205 33.7 70 45 215 28.0 71 45 225 23.8 72 45 235 23.8 77 45 285 33.6 78 45 295 28.5 79 45 305 27.6 80 45 315 29.4 81 45 325 26.9 82 45 335 24.0 83 45 345 25.5 84 45 355 29.5 85 35 5 27.8 86 35 15 18.4 87 35 25 6.8 88 35 35 4.3 97 35 125 31.6 98 35 135 39.4 99 35 145 37.7 100 35 155 30.0 101 35 165 30.2 102 35 175 33.5 103 35 185 40.2 104 35 195 35.8 105 35 205 24.8 106 35 215 20.6 107 35 225 14.6 108 35 235 14.0 109 35 245 13.7 112 35 275 44.3 113 35 285 38.2 114 35 295 29.4 115 35 305 27.4 116 35 315 28.7 117 35 325 24.0 118 35 335 20.0 119 35 345 16.8 120 35 355 23.9 124 25 35 8.9 125 25 45 4.8 126 25 55 4.9 127 25 65 14.3 132 25 115 34.0 133 25 125 31.6 134 25 135 41.2 135 25 145 34.7 136 25 155 27.9 137 25 165 27.3 138 25 175 29.7 139 25 185 33.2 140 25 195 26.5 141 25 205 19.9 142 25 215 17.2 143 25 225 17.8 144 25 235 18.1 145 25 245 19.4 146 25 255 35.5 147 25 265 42.6 148 25 275 49.0 149 25 285 42.8 150 25 295 34.5 151 25 305 27.3 152 25 315 24.2 153 25 325 16.7 154 25 335 13.5 155 25 345 13.6 160 15 35 23.4 161 15 45 19.0 162 15 55 13.5 163 15 65 22.8 164 15 75 41.4 165 15 85 48.2 166 15 95 57.4 167 15 105 53.0 168 15 115 42.4 169 15 125 41.3 170 15 135 49.5 171 15 145 50.4 172 15 155 42.0 173 15 165 35.0 174 15 175 35.9 175 15 185 45.7 176 15 195 35.5 177 15 205 26.8 178 15 215 29.1 179 15 225 26.1 180 15 235 23.9 181 15 245 35.9 182 15 255 46.3 183 15 265 56.5 184 15 275 60.0 185 15 285 44.4 186 15 295 34.6 187 15 305 29.8 188 15 315 28.0 189 15 325 22.8 190 15 335 22.5 191 15 345 28.7 193 5 5 46.8 197 5 45 16.1 198 5 55 20.2 199 5 65 29.8 200 5 75 42.7 201 5 85 55.1 202 5 95 68.0 203 5 105 53.4 204 5 115 48.4 205 5 125 53.4 206 5 135 52.9 207 5 145 49.8 208 5 155 46.8 209 5 165 44.4 210 5 175 41.8 211 5 185 46.1 212 5 195 33.5 213 5 205 25.9 214 5 215 26.7 215 5 225 25.4 216 5 235 25.5 217 5 245 19.9 218 5 255 40.0 219 5 265 47.2 220 5 275 59.5 221 5 285 56.5 223 5 305 29.6 224 5 315 19.5 225 5 325 16.9 226 5 335 23.4 227 5 345 29.3 228 5 355 23.5 229 -5 5 21.0 230 -5 15 18.3 233 -5 45 12.1 234 -5 55 18.4 235 -5 65 40.7 236 -5 75 42.2 237 -5 85 53.3 238 -5 95 60.0 239 -5 105 45.0 240 -5 115 28.9 241 -5 125 28.7 242 -5 135 27.1 243 -5 145 47.1 244 -5 155 41.3 245 -5 165 39.4 246 -5 175 35.4 247 -5 185 46.3 248 -5 195 22.1 249 -5 205 15.0 250 -5 215 13.2 251 -5 225 5.5 252 -5 235 4.9 253 -5 245 6.8 254 -5 255 12.0 255 -5 265 17.7 256 -5 275 32.0 260 -5 315 13.7 261 -5 325 10.2 262 -5 335 8.1 263 -5 345 9.2 264 -5 355 10.6 265 -15 5 11.9 266 -15 15 14.5 268 -15 35 5.6 269 -15 45 6.9 270 -15 55 12.1 271 -15 65 13.6 272 -15 75 22.9 273 -15 85 30.6 274 -15 95 34.1 275 -15 105 16.3 276 -15 115 8.9 277 -15 125 12.3 278 -15 135 25.7 279 -15 145 18.0 280 -15 155 18.2 281 -15 165 24.7 282 -15 175 32.3 283 -15 185 29.4 284 -15 195 27.7 285 -15 205 13.5 286 -15 215 14.4 287 -15 225 9.8 288 -15 235 12.8 289 -15 245 16.6 290 -15 255 13.5 292 -15 275 19.1 293 -15 285 24.1 297 -15 325 19.7 298 -15 335 13.7 299 -15 345 16.6 300 -15 355 16.7 301 -25 5 18.4 302 -25 15 14.2 304 -25 35 10.6 305 -25 45 8.8 306 -25 55 9.1 307 -25 65 11.8 308 -25 75 17.9 309 -25 85 10.8 310 -25 95 16.3 311 -25 105 13.7 312 -25 115 6.9 316 -25 155 8.8 317 -25 165 13.6 318 -25 175 18.7 319 -25 185 24.5 320 -25 195 21.3 321 -25 205 27.9 322 -25 215 27.3 323 -25 225 24.1 324 -25 235 19.4 328 -25 275 13.4 329 -25 285 12.1 332 -25 315 29.6 333 -25 325 21.6 334 -25 335 20.4 335 -25 345 23.4 336 -25 355 21.6 337 -35 5 28.6 338 -35 15 21.6 339 -35 25 23.9 340 -35 35 14.3 341 -35 45 16.2 342 -35 55 14.2 343 -35 65 14.3 344 -35 75 17.5 345 -35 85 17.2 346 -35 95 18.8 347 -35 105 15.0 348 -35 115 14.7 349 -35 125 16.9 350 -35 135 19.8 351 -35 145 25.3 352 -35 155 20.0 353 -35 165 19.5 354 -35 175 20.3 355 -35 185 25.2 356 -35 195 20.4 357 -35 205 22.3 358 -35 215 28.4 364 -35 275 20.0 365 -35 285 21.9 367 -35 305 26.3 368 -35 315 19.0 369 -35 325 24.5 371 -35 345 21.0 372 -35 355 31.5 387 -45 145 28.1 388 -45 155 20.0 389 -45 165 28.3 390 -45 175 25.3 391 -45 185 30.5 402 -45 295 32.9 403 -45 305 21.7 417 -55 170 21.3 423 -55 290 29.7 424 -55 310 29.2 425 -55 330 10.0