Table 160 (continued) 4^5 



HORIZONTAL VISIBILITY 



Table 160-B2. — Extinction coefficient as a function of visual range of black objects viewed 

 against horizon sky in daytime where threshold of luminance contrast, c, is 0.05 



2.996 

 <r = - 



Vt 



012345678 



Visual 

 range 



V B 



km. km.- 1 km.- 1 km.- 1 km. -1 km.- 1 km. -1 km.- 1 km.- 1 km. -1 km.- 1 



10 .2996 .2724 .2497 .2305 .2140 .1997 .1873 .1762 .1664 .1577 



20 .1498 .1427 .1362 .1303 .1248 .1198 .1152 .1110 .1070 .1033 



30 .09987 .09665 .09363 .09079 .08812 .08560 .08322 .08097 .07884 .07682 



40 .07490 .07307 .07133 .06967 .06809 .06658 .06513 .06374 .06242 .06114 



50 .05992 .05875 .05762 .05653 .05548 .05447 .05350 .05256 .05166 .05078 



60 .04993 .04911 .04832 .04756 .04681 .04609 .04539 .04472 .04406 .04342 



70 .04280 .04220 .04161 .04104 .04049 .03995 .03942 .03891 .03841 .03792 



80 .03745 .03699 .03654 .03610 .03567 .03525 .03484 .03444 .03405 .03366 



90 .03329 .03292 .03257 .03222 .03187 .03154 .03121 .03089 .03057 .03026 



100 .02996 .02966 .02937 .02909 .02881 .02853 .02826 .02800 .02774 .02749 



110 .02724 .02699 .02675 .02651 .02628 .02605 .02583 .02561 .02539 .02518 



120 .02497 .02476 .02456 .02436 .02416 .02397 .02378 .02359 .02341 .02322 



130 .02305 .02287 .02270 .02253 .02236 .02219 .02203 .02187 .02171 .02155 



140 .02140 .02125 .02110 .02095 .02081 .02066 .02052 .02038 .02024 .02011 



150 .01997 .01984 .01971 .01958 .01945 .01933 .01921 .01908 .01896 .01884 



160 .01873 .01861 .01849 .01838 .01827 .01816 .01805 .01794 .01783 .01773 



170 .01762 .01752 .01742 .01732 .01722 .01712 .01702 .01693 .01683 .01674 



180 .01664 .01655 .01646 .01637 .01628 .01619 .01611 .01602 .01594 .01585 



190 .01577 .01569 .01560 .01552 .01544 .01536 .01529 .01521 .01513 .01506 



200 .01498 .01491 .01483 .01476 .01469 .01461 .01454 .01447 .01440 .01433 



210 .01427 .01420 .01413 .01407 .01400 .01393 .01387 .01381 .01374 .01368 



220 .01362 .01356 .01350 .01343 .01338 .01332 .01326 .01320 .01314 .01308 



230 .01303 .01297 .01291 .01286 .01280 .01275 .01269 .01264 .01259 .01254 



240 .01248 .01243 .01238 .01233 .01228 .01223 .01218 .01213 .01208 .01203 



250 .01198 .01194 .01189 .01184 .01180 .01175 .01170 .01166 .01161 .01157 



(continued) 



SMITHSONIAN METEOROLOGICAL TABLES 



