Annual sea ice indices for: Anvers ('Anvr_') is the small (~50km) foraging area west and south of Anvers Island Lavoisier ('Lavo_') is the small (~50km) foraging area west and south of Lavosier Island Avian ('Avia_') is the small (~50km) foraging area west and south of Avian Island Charcot ('Char_') is the small (~50km) foraging area west of Alexander Island Annual sea ice year goes from mid-Feb to mid-Feb, so from year day 46 to 410 adv is the year day of advance ret is the year day of retreat dur is the ice season duration (days elapsed between adv and ret) idy is the actual sea ice days between adv and ret Dataset: Sea ice indices are derived from daily GSFC Bootstrap version 2.0 sea ice concentration, except for Jan 2013 to Feb 2014, which are preliminary data from Near-Real Time Sea Ice (NRTSI) using NASA Team algorith Ice Year Anvr Anvr Anvr Anvr Lavo Lavo Lavo Lavo Avia Avia Avia Avia Char Char Char Char adv ret dur idy adv ret dur idy adv ret dur idy adv ret dur idy 1979-80 118 385 267 251 88 391 304 285 46 410 365 340 46 410 365 365 1980-81 99 381 283 237 78 388 311 285 47 405 359 348 47 411 365 365 1981-82 145 375 231 229 127 388 262 255 96 409 313 303 47 409 363 363 1982-83 172 362 191 181 162 372 211 203 90 377 288 254 46 410 365 365 1983-84 228 330 103 89 215 339 125 111 155 351 197 193 47 409 363 363 1984-85 180 348 169 141 168 346 179 177 146 341 196 196 46 410 364 318 1985-86 201 330 130 104 188 372 185 173 160 370 211 210 46 410 365 324 1986-87 165 390 225 211 137 399 263 229 133 407 275 274 47 409 363 362 1987-88 163 334 171 170 147 351 205 200 90 401 311 305 46 410 365 365 1988-89 212 287 76 73 179 312 133 118 87 328 242 199 46 382 337 337 1989-90 0 0 0 0 234 271 37 28 152 313 161 148 106 357 251 237 1990-91 236 336 100 100 218 347 129 128 174 360 186 180 111 378 268 265 1991-92 164 349 186 165 152 387 236 234 138 387 249 249 123 410 287 287 1992-93 161 318 158 126 145 327 183 182 110 388 279 272 46 408 363 362 1993-94 175 316 142 125 166 340 174 167 129 365 236 230 63 410 347 318 1994-95 194 341 148 148 161 353 193 173 139 369 231 229 46 402 357 330 1995-96 178 360 182 168 167 377 211 211 152 376 225 223 88 410 322 306 1996-97 202 311 110 90 177 343 166 162 163 353 191 191 46 403 358 321 1997-98 184 330 147 137 168 346 178 178 133 357 225 220 108 393 286 286 1998-99 223 335 112 107 160 331 172 153 139 336 198 186 125 381 256 256 1999-00 213 339 126 114 208 370 162 154 165 386 221 219 156 410 255 254 2000-01 233 308 76 68 186 317 131 112 161 343 182 177 81 398 318 280 2001-02 202 340 138 133 192 378 186 185 173 374 201 199 121 405 285 265 2002-03 171 317 146 137 122 341 220 199 130 362 232 232 76 403 328 305 2003-04 205 309 105 85 203 335 132 131 140 340 200 199 118 387 270 270 2004-05 209 362 153 153 198 388 191 191 161 398 237 232 127 411 284 284 2005-06 192 353 162 155 163 369 207 207 115 395 281 276 46 410 365 364 2006-07 222 301 79 75 194 331 138 135 161 338 178 178 46 383 338 328 2007-08 218 271 54 52 196 307 112 100 171 314 144 141 114 371 257 243 2008-09 221 263 42 36 203 300 97 78 188 319 132 129 131 367 237 218 2009-10 225 306 82 80 200 325 126 120 185 333 149 148 112 378 267 235 2010-11 205 272 68 62 201 281 81 77 167 290 124 120 98 366 269 253 2011-12 206 321 115 112 204 346 143 143 180 380 201 201 114 407 294 274 2012-13 222 312 90 75 214 345 132 126 160 341 182 182 46 387 342 271 2013-14 198 364 167 165 177 365 188 185 148 366 219 218 123 409 287 287 2014-15 200 314 114 106 190 338 149 149 152 364 212 211 92 391 300 268