964:
1198:
per square yard. It is also sometimes specified in ounces per yard in a standard width for the particular cloth. One gram per square meter equals 0.0295 ounces per square yard; one ounce per square yard equals 33.9 grams per square meter.
994:
In astronomy, the column density is generally used to indicate the number of atoms or molecules per square cm (cm) along the line of sight in a particular direction, as derived from observations of e.g. the 21-cm
737:
1074:
601:
550:
943:
228:
778:
1398:
C. Melsheimer; G. Heygster; N. Mathew; L. Toudal
Pedersen (2009). "Retrieval of Sea Ice Emissivity and Integrated Retrieval of Surface and Atmospheric Parameters over the Arctic from
1139:
361:
139:
1098:
denotes the vertical coordinate (e.g., height or depth), or as the number or count of a substanceārather than the massāper unit area integrated along a path (column number density):
403:
176:
807:
680:
834:
651:
63:
857:
509:
1318:
R. Sinreich; U. FrieĆ; T. Wagner; S. Yilmaz; U. Platt (2008). "Retrieval of
Aerosol Distributions by Multi-Axis Differential Absorption Spectroscopy (MAX-DOAS)".
1096:
621:
1214:
When studying bodies falling through air, area density is important because resistance depends on area, and gravitational force is dependent on mass.
685:
1208:
1335:
1302:
881:
1038:
565:
514:
1014:. In the case of a disk seen face-on, area density for a given area of the disk is defined as column density: that is, either as the
905:
1473:
1352:
1220:
is often expressed in grams per square centimeter (gĀ·cm) as measured by x-ray absorptiometry, as a proxy for the actual density.
1149:
877:
1103:
326:
366:
1468:
1458:
1227:
is expressed in units of kilograms per square meter, though the area figure is nominal, being the square of the height.
192:
555:
742:
20:
104:
902:, which specifies the volume per unit area or depth instead of mass per unit area, thus the two are related:
294:
and is expressed in grams per square meter (g/m); for paper in particular, it may be expressed as pounds per
1231:
1000:
1154:
Areal density is used to quantify and compare different types media used in data storage devices such as
1463:
1237:
145:
1364:
1180:
The area density is often used to describe the thickness of paper; e.g., 80 g/m is very common.
859:
have units of, for example, grams per cubic metre, grams per square metre, and metres, respectively.
185:
1351:
C. Melsheimer; G. Heygster (2008). "Improved retrieval of total water vapor over polar regions from
783:
656:
559:
308:
303:
1380:
1019:
478:
312:
812:
629:
41:
1331:
1298:
899:
839:
1372:
1323:
1155:
494:
1224:
1194:
Fabric "weight" is often specified as mass per unit area, grams per square meter (gsm) or
276:
880:(TOMS) which retrieves ozone columns around the globe. Columns are also returned by the
1368:
1417:
1254:
1249:
1081:
1011:
873:
606:
562:). A common special case is a vertical path, from the bottom to the top of the medium:
554:
In general the integration path can be slant or oblique incidence (as in, for example,
963:
1452:
1431:
1259:
996:
948:
1384:
1217:
1159:
284:
80:
19:
This article is about the property of two-dimensional objects. For other uses, see
1327:
1163:
892:
295:
1376:
1030:
889:
1189:
1175:
1026:
485:
291:
280:
489:
433:
69:
1166:. The current unit of measure is typically gigabits per square inch.
1195:
885:
1234:
in the ionosphere is a quantity of type columnar number density.
653:
is closely related to the vertically averaged volumetric density
1399:
1023:
1015:
482:
474:
272:
268:
999:
or from observations of a certain molecular species. Also the
958:
732:{\displaystyle {\bar {\rho }}={\frac {\rho _{A}}{\Delta z}},}
1010:
The concept of area density can be useful when analysing
623:
denotes the vertical coordinate (e.g., height or depth).
1295:
Fundamentals of physics and chemistry of the atmosphere
975:
745:
1106:
1084:
1041:
908:
842:
815:
786:
688:
659:
632:
609:
568:
517:
497:
369:
329:
195:
148:
107:
44:
1029:along the vertical path that goes through the disk
882:
differential optical absorption spectroscopy (DOAS)
267:) of a two-dimensional object is calculated as the
184:
91:
78:
68:
33:
28:
1133:
1090:
1069:{\displaystyle \sigma =\int \rho \,\mathrm {d} z,}
1068:
937:
851:
828:
801:
772:
731:
674:
645:
615:
596:{\displaystyle \sigma =\int \rho \,\mathrm {d} z,}
595:
545:{\displaystyle \sigma =\int \rho \,\mathrm {d} s.}
544:
503:
397:
355:
222:
170:
133:
57:
290:In the paper and fabric industries, it is called
938:{\displaystyle P={\frac {\sigma }{\rho _{0}}}.}
884:method and are a common retrieval product from
223:{\displaystyle {\mathsf {L}}^{-2}{\mathsf {M}}}
1404:Journal of the Remote Sensing Society of Japan
1003:can be related to the column density of H or H
1406:. Vol. 29, no. 1. pp. 236ā241.
1240:is a quantity of type columnar mass density.
8:
1033:, from the bottom to the top of the medium:
898:A closely related concept is that of ice or
1278:Egbert Boeker; Rienk van Grondelle (2000).
773:{\textstyle \Delta z=\int 1\,\mathrm {d} z}
1207:It is also an important quantity for the
1120:
1119:
1105:
1083:
1055:
1054:
1040:
924:
915:
907:
841:
820:
814:
788:
787:
785:
762:
761:
744:
710:
704:
690:
689:
687:
661:
660:
658:
637:
631:
608:
582:
581:
567:
531:
530:
516:
496:
488:along a path; It is obtained integrating
450:A special type of area density is called
374:
368:
343:
334:
328:
214:
213:
204:
198:
197:
194:
153:
147:
121:
112:
106:
49:
43:
1134:{\displaystyle N=\int n\,\mathrm {d} z.}
442:is the average thickness of the object.
356:{\displaystyle \rho _{A}={\frac {m}{A}}}
134:{\displaystyle \rho _{A}={\frac {m}{A}}}
1270:
872:It is a quantity commonly retrieved by
398:{\displaystyle \rho _{A}=\rho \cdot l,}
215:
199:
25:
7:
307:can be defined by replacing mass by
1320:Nucleation and Atmospheric Aerosols
947:Another closely related concept is
323:Area density can be calculated as:
1121:
1056:
843:
763:
746:
717:
583:
532:
298:of standard sizes ("basis ream").
14:
1297:. Berlin: Springer. p. 470.
426:is the total area of the object,
420:is the total mass of the object,
1150:Areal density (computer storage)
962:
878:Total Ozone Mapping Spectrometer
171:{\displaystyle \rho _{A}=\rho l}
1357:IEEE Trans. Geosci. Remote Sens
1355:-B microwave radiometer data".
1418:"Column Density | COSMOS"
876:instruments, for instance the
802:{\displaystyle {\bar {\rho }}}
793:
695:
675:{\displaystyle {\bar {\rho }}}
666:
1:
1328:10.1007/978-1-4020-6475-3_227
414:is the average area density,
315:, with resulting units of m.
1490:
1187:
1173:
1147:
18:
1434:. Webopedia. 3 March 1997
829:{\displaystyle \rho _{A}}
646:{\displaystyle \rho _{A}}
556:line of sight propagation
58:{\displaystyle \rho _{A}}
1474:Area-specific quantities
1377:10.1109/TGRS.2008.918013
1293:Visconti, Guido (2001).
852:{\displaystyle \Delta z}
21:Density (disambiguation)
1209:absorption of radiation
1001:interstellar extinction
1322:. pp. 1145ā1149.
1282:(2nd ed.). Wiley.
1232:total electron content
1135:
1092:
1070:
939:
853:
830:
803:
774:
733:
676:
647:
617:
597:
546:
505:
399:
357:
224:
172:
135:
59:
1280:Environmental Physics
1238:Snow water equivalent
1136:
1093:
1071:
940:
854:
831:
804:
775:
734:
677:
648:
618:
598:
547:
506:
504:{\displaystyle \rho }
456:columnar mass density
400:
358:
225:
173:
136:
60:
1104:
1082:
1039:
906:
840:
813:
784:
743:
686:
657:
630:
607:
566:
515:
495:
367:
327:
193:
146:
105:
42:
1469:Classical mechanics
1459:Atmospheric physics
1369:2008ITGRS..46.2307M
1160:optical disc drives
868:Atmospheric physics
560:atmospheric physics
309:number of particles
304:area number density
249:superficial density
1144:Data storage media
1131:
1088:
1066:
974:. You can help by
935:
849:
826:
799:
770:
729:
672:
643:
613:
593:
542:
501:
490:volumetric density
395:
353:
313:countable quantity
220:
168:
131:
82:SI base units
55:
16:Mass per unit area
1337:978-1-4020-6474-6
1304:978-3-540-67420-7
1091:{\displaystyle z}
992:
991:
930:
900:liquid water path
796:
724:
698:
669:
626:Columnar density
616:{\displaystyle z}
351:
265:density thickness
233:
232:
129:
1481:
1444:
1443:
1441:
1439:
1428:
1422:
1421:
1414:
1408:
1407:
1395:
1389:
1388:
1363:(8): 2307ā2322.
1348:
1342:
1341:
1315:
1309:
1308:
1290:
1284:
1283:
1275:
1156:hard disk drives
1140:
1138:
1137:
1132:
1124:
1097:
1095:
1094:
1089:
1075:
1073:
1072:
1067:
1059:
987:
984:
966:
959:
944:
942:
941:
936:
931:
929:
928:
916:
858:
856:
855:
850:
835:
833:
832:
827:
825:
824:
808:
806:
805:
800:
798:
797:
789:
779:
777:
776:
771:
766:
738:
736:
735:
730:
725:
723:
715:
714:
705:
700:
699:
691:
681:
679:
678:
673:
671:
670:
662:
652:
650:
649:
644:
642:
641:
622:
620:
619:
614:
602:
600:
599:
594:
586:
551:
549:
548:
543:
535:
510:
508:
507:
502:
440:
430:
424:
418:
412:
404:
402:
401:
396:
379:
378:
362:
360:
359:
354:
352:
344:
339:
338:
229:
227:
226:
221:
219:
218:
212:
211:
203:
202:
177:
175:
174:
169:
158:
157:
140:
138:
137:
132:
130:
122:
117:
116:
95:other quantities
93:Derivations from
83:
64:
62:
61:
56:
54:
53:
26:
1489:
1488:
1484:
1483:
1482:
1480:
1479:
1478:
1449:
1448:
1447:
1437:
1435:
1432:"Areal Density"
1430:
1429:
1425:
1416:
1415:
1411:
1397:
1396:
1392:
1350:
1349:
1345:
1338:
1317:
1316:
1312:
1305:
1292:
1291:
1287:
1277:
1276:
1272:
1268:
1246:
1225:body mass index
1205:
1192:
1186:
1178:
1172:
1152:
1146:
1102:
1101:
1080:
1079:
1037:
1036:
1031:(line-of-sight)
1012:accretion disks
1006:
988:
982:
979:
972:needs expansion
957:
920:
904:
903:
870:
865:
838:
837:
816:
811:
810:
782:
781:
741:
740:
716:
706:
684:
683:
655:
654:
633:
628:
627:
605:
604:
564:
563:
513:
512:
511:over a column:
493:
492:
468:
448:
438:
432:is the average
428:
422:
416:
411:
407:
370:
365:
364:
330:
325:
324:
321:
277:SI derived unit
245:surface density
239:(also known as
196:
191:
190:
180:
149:
144:
143:
108:
103:
102:
96:
94:
81:
45:
40:
39:
36:
24:
17:
12:
11:
5:
1487:
1485:
1477:
1476:
1471:
1466:
1461:
1451:
1450:
1446:
1445:
1423:
1409:
1390:
1343:
1336:
1310:
1303:
1285:
1269:
1267:
1264:
1263:
1262:
1257:
1255:Linear density
1252:
1250:Areic quantity
1245:
1242:
1204:
1201:
1188:Main article:
1185:
1182:
1174:Main article:
1171:
1168:
1148:Main article:
1145:
1142:
1130:
1127:
1123:
1118:
1115:
1112:
1109:
1087:
1065:
1062:
1058:
1053:
1050:
1047:
1044:
1004:
990:
989:
969:
967:
956:
953:
934:
927:
923:
919:
914:
911:
874:remote sensing
869:
866:
864:
861:
848:
845:
823:
819:
795:
792:
769:
765:
760:
757:
754:
751:
748:
728:
722:
719:
713:
709:
703:
697:
694:
668:
665:
640:
636:
612:
592:
589:
585:
580:
577:
574:
571:
541:
538:
534:
529:
526:
523:
520:
500:
466:
460:column density
452:column density
447:
446:Column density
444:
409:
394:
391:
388:
385:
382:
377:
373:
350:
347:
342:
337:
333:
320:
317:
261:column density
257:mass thickness
231:
230:
217:
210:
207:
201:
188:
182:
181:
179:
178:
167:
164:
161:
156:
152:
141:
128:
125:
120:
115:
111:
99:
97:
92:
89:
88:
85:
76:
75:
72:
66:
65:
52:
48:
37:
35:Common symbols
34:
31:
30:
15:
13:
10:
9:
6:
4:
3:
2:
1486:
1475:
1472:
1470:
1467:
1465:
1462:
1460:
1457:
1456:
1454:
1433:
1427:
1424:
1419:
1413:
1410:
1405:
1401:
1394:
1391:
1386:
1382:
1378:
1374:
1370:
1366:
1362:
1358:
1354:
1347:
1344:
1339:
1333:
1329:
1325:
1321:
1314:
1311:
1306:
1300:
1296:
1289:
1286:
1281:
1274:
1271:
1265:
1261:
1260:Paper density
1258:
1256:
1253:
1251:
1248:
1247:
1243:
1241:
1239:
1235:
1233:
1228:
1226:
1221:
1219:
1215:
1212:
1210:
1202:
1200:
1197:
1191:
1183:
1181:
1177:
1169:
1167:
1165:
1161:
1157:
1151:
1143:
1141:
1128:
1125:
1116:
1113:
1110:
1107:
1099:
1085:
1076:
1063:
1060:
1051:
1048:
1045:
1042:
1034:
1032:
1028:
1025:
1021:
1017:
1013:
1008:
1002:
998:
997:hydrogen line
986:
977:
973:
970:This section
968:
965:
961:
960:
954:
952:
950:
949:optical depth
945:
932:
925:
921:
917:
912:
909:
901:
896:
894:
891:
887:
883:
879:
875:
867:
862:
860:
846:
821:
817:
790:
767:
758:
755:
752:
749:
726:
720:
711:
707:
701:
692:
663:
638:
634:
624:
610:
590:
587:
578:
575:
572:
569:
561:
557:
552:
539:
536:
527:
524:
521:
518:
498:
491:
487:
484:
480:
476:
472:
465:
461:
457:
453:
445:
443:
441:
435:
431:
425:
419:
413:
392:
389:
386:
383:
380:
375:
371:
348:
345:
340:
335:
331:
318:
316:
314:
310:
306:
305:
299:
297:
293:
288:
286:
282:
278:
274:
270:
266:
262:
258:
254:
253:areic density
250:
246:
242:
241:areal density
238:
208:
205:
189:
187:
183:
165:
162:
159:
154:
150:
142:
126:
123:
118:
113:
109:
101:
100:
98:
90:
86:
84:
77:
73:
71:
67:
50:
46:
38:
32:
27:
22:
1464:Mass density
1436:. Retrieved
1426:
1412:
1403:
1393:
1360:
1356:
1346:
1319:
1313:
1294:
1288:
1279:
1273:
1236:
1229:
1222:
1218:Bone density
1216:
1213:
1206:
1193:
1179:
1153:
1100:
1077:
1035:
1009:
993:
980:
976:adding to it
971:
946:
897:
871:
625:
553:
473:. It is the
470:
463:
459:
455:
451:
449:
437:
427:
421:
415:
406:
322:
302:
300:
289:
285:square metre
264:
260:
256:
252:
248:
244:
240:
237:area density
236:
234:
70:SI unit
29:Area density
1164:tape drives
983:August 2015
893:radiometers
462:), denoted
319:Formulation
287:" (kgĀ·m).
1453:Categories
1402:-E data".
1266:References
1027:integrated
486:integrated
458:or simply
301:A related
1114:∫
1052:ρ
1049:∫
1043:σ
1022:per unit
1020:substance
955:Astronomy
922:ρ
918:σ
890:microwave
888:-looking
844:Δ
818:ρ
794:¯
791:ρ
756:∫
747:Δ
718:Δ
708:ρ
696:¯
693:ρ
667:¯
664:ρ
635:ρ
579:ρ
576:∫
570:σ
528:ρ
525:∫
519:σ
499:ρ
481:per unit
479:substance
387:⋅
384:ρ
372:ρ
332:ρ
311:or other
271:per unit
206:−
186:Dimension
163:ρ
151:ρ
110:ρ
47:ρ
1438:April 9,
1385:20910677
1244:See also
1190:grammage
1176:grammage
292:grammage
281:kilogram
279:is the "
1365:Bibcode
434:density
1383:
1334:
1301:
1196:ounces
1184:Fabric
1078:where
836:, and
739:where
603:where
454:(also
436:, and
405:where
275:. The
1381:S2CID
1203:Other
1170:Paper
886:nadir
863:Usage
263:, or
1440:2014
1400:AMSR
1353:AMSU
1332:ISBN
1299:ISBN
1230:The
1223:The
1162:and
1024:area
1016:mass
483:area
475:mass
296:ream
283:per
273:area
269:mass
235:The
87:mā
kg
74:kg/m
1373:doi
1324:doi
1211:.
1018:of
978:.
682:as
558:in
477:of
469:or
363:or
79:In
1455::
1379:.
1371:.
1361:46
1359:.
1330:.
1158:,
1007:.
951:.
895:.
809:,
780:;
259:,
255:,
251:,
247:,
243:,
1442:.
1420:.
1387:.
1375::
1367::
1340:.
1326::
1307:.
1129:.
1126:z
1122:d
1117:n
1111:=
1108:N
1086:z
1064:,
1061:z
1057:d
1046:=
1005:2
985:)
981:(
933:.
926:0
913:=
910:P
847:z
822:A
768:z
764:d
759:1
753:=
750:z
727:,
721:z
712:A
702:=
639:A
611:z
591:,
588:z
584:d
573:=
540:.
537:s
533:d
522:=
471:Ļ
467:A
464:Ļ
439:l
429:Ļ
423:A
417:m
410:A
408:Ļ
393:,
390:l
381:=
376:A
349:A
346:m
341:=
336:A
216:M
209:2
200:L
166:l
160:=
155:A
127:A
124:m
119:=
114:A
51:A
23:.
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