462 Table 160 (continued) 



HORIZONTAL VISIBILITY 



Table 160-B1. — Extinction coefficient as a function of visual range of black objects viewed 

 against borizon sky in daytime where threshold of luminance contrast, c, is 0.02 



3.912 



40 .09780 .09541 .09314 .09098 .08891 .08693 .08504 .08323 .08150 .07984 



50 .07824 .07671 .07523 .07381 .07244 .07113 .06986 .06863 .06745 .06631 



60 .06520 .06413 .06310 .06210 .06112 .06018 .05927 .05839 .05753 .05670 



70 .05589 .05510 .05433 .05359 .05286 .05216 .05147 .05081 .05015 .04952 



80 .04890 .04830 .04771 .04713 .04657 .04602 .04549 .04497 .04445 .04396 



90 .04347 .04299 .04252 .04206 .04162 .04118 .04075 .04033 .03992 .03952 



100 .03912 .03873 .03835 .03798 .03762 0.3726 .03691 .03656 .03622 .03589 



110 .03556 .03524 .03493 .03462 .03432 .03402 .03372 .03344 .03315 .03287 



120 .03260 .03233 .03207 .03180 .03155 .03130 .03105 .03080 .03056 .03033 



130 .03009 .02986 .02964 .02941 .02919 .02898 .02876 .02855 .02835 .02814 



140 .02794 .02774 .02755 .02736 .02717 .02698 .02679 .02661 .02643 .02626 



150 .02608 .02591 .02574 .02557 .02540 .02524 .02508 .02492 .02476 .02460 



160 .02445 .02430 .02415 .02400 .02385 .02371 .02357 .02343 .02329 .02315 



170 .02301 .02288 .02274 .02261 ..02248 .02235 .02223 .02210 .02198 .02185 



180 .02173 .02161 .02149 .02138 .02126 .02115 .02103 .02092 .02081 .02070 



190 .02059 .02048 .02037 .02027 .02016 .02006 .01996 .01986 .01976 .01966 



200 .01956 .01946 .01937 .01927 .01918 .01908 .01899 .01890 .01881 .01872 



210 .01863 .01854 .01845 .01837 .01828 .01820 .01811 .01803 .01794 .01786 



220 .01778 .01770 .01762 .01754 .01746 .01739 .01731 .01723 .01716 .01708 



230 .01701 .01694 .01686 .01679 .01672 .01665 .01658 .01651 .01644 .01637 



240 .01630 .01623 .01617 .01610 .01603 .01597 .01590 .01584 .01577 .01571 



250 .01565 .01559 .01552 .01546 .01540 .01534 .01528 .01522 .01516 .01510 



(continued) 



SMITHSONIAN METEOROLOGICAL TABLES 



