975:
1209:
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.
1005:
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
748:
1085:
612:
561:
954:
239:
789:
1409:
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
1150:
372:
150:
1109:
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):
414:
187:
818:
691:
845:
662:
74:
868:
520:
1329:
R. Sinreich; U. FrieĆ; T. Wagner; S. Yilmaz; U. Platt (2008). "Retrieval of
Aerosol Distributions by Multi-Axis Differential Absorption Spectroscopy (MAX-DOAS)".
1107:
632:
1225:
When studying bodies falling through air, area density is important because resistance depends on area, and gravitational force is dependent on mass.
696:
1219:
1346:
1313:
892:
1049:
576:
525:
1025:. 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
916:
1484:
1363:
1231:
is often expressed in grams per square centimeter (gĀ·cm) as measured by x-ray absorptiometry, as a proxy for the actual density.
1160:
888:
1114:
337:
377:
1479:
1469:
1238:
is expressed in units of kilograms per square meter, though the area figure is nominal, being the square of the height.
203:
566:
753:
31:
115:
913:, which specifies the volume per unit area or depth instead of mass per unit area, thus the two are related:
305:
and is expressed in grams per square meter (g/m); for paper in particular, it may be expressed as pounds per
1242:
1011:
1165:
Areal density is used to quantify and compare different types media used in data storage devices such as
1474:
1248:
156:
1375:
1191:
The area density is often used to describe the thickness of paper; e.g., 80 g/m is very common.
870:
have units of, for example, grams per cubic metre, grams per square metre, and metres, respectively.
196:
1362:
C. Melsheimer; G. Heygster (2008). "Improved retrieval of total water vapor over polar regions from
794:
667:
570:
319:
314:
1391:
1030:
489:
323:
823:
640:
52:
1342:
1309:
910:
850:
1383:
1334:
1166:
505:
1235:
1205:
Fabric "weight" is often specified as mass per unit area, grams per square meter (gsm) or
287:
891:(TOMS) which retrieves ozone columns around the globe. Columns are also returned by the
1379:
1428:
1265:
1260:
1092:
1022:
884:
617:
573:). A common special case is a vertical path, from the bottom to the top of the medium:
565:
In general the integration path can be slant or oblique incidence (as in, for example,
974:
1463:
1442:
1270:
1007:
959:
1395:
1228:
1170:
295:
91:
30:
This article is about the property of two-dimensional objects. For other uses, see
1338:
1174:
903:
306:
1387:
17:
1041:
900:
1200:
1186:
1037:
496:
302:
291:
500:
444:
80:
1177:. The current unit of measure is typically gigabits per square inch.
1206:
896:
1245:
in the ionosphere is a quantity of type columnar number density.
664:
is closely related to the vertically averaged volumetric density
1410:
1034:
1026:
493:
485:
283:
279:
1010:
or from observations of a certain molecular species. Also the
969:
743:{\displaystyle {\bar {\rho }}={\frac {\rho _{A}}{\Delta z}},}
1021:
The concept of area density can be useful when analysing
634:
denotes the vertical coordinate (e.g., height or depth).
1306:
Fundamentals of physics and chemistry of the atmosphere
986:
756:
1117:
1095:
1052:
919:
853:
826:
797:
699:
670:
643:
620:
579:
528:
508:
380:
340:
206:
159:
118:
55:
1040:along the vertical path that goes through the disk
893:
differential optical absorption spectroscopy (DOAS)
278:) of a two-dimensional object is calculated as the
195:
102:
89:
79:
44:
39:
1144:
1101:
1080:{\displaystyle \sigma =\int \rho \,\mathrm {d} z,}
1079:
948:
862:
839:
812:
783:
742:
685:
656:
626:
607:{\displaystyle \sigma =\int \rho \,\mathrm {d} z,}
606:
556:{\displaystyle \sigma =\int \rho \,\mathrm {d} s.}
555:
514:
408:
366:
233:
181:
144:
68:
301:In the paper and fabric industries, it is called
949:{\displaystyle P={\frac {\sigma }{\rho _{0}}}.}
895:method and are a common retrieval product from
234:{\displaystyle {\mathsf {L}}^{-2}{\mathsf {M}}}
1415:Journal of the Remote Sensing Society of Japan
1014:can be related to the column density of H or H
1417:. Vol. 29, no. 1. pp. 236ā241.
1251:is a quantity of type columnar mass density.
8:
1044:, from the bottom to the top of the medium:
909:A closely related concept is that of ice or
1289:Egbert Boeker; Rienk van Grondelle (2000).
784:{\textstyle \Delta z=\int 1\,\mathrm {d} z}
1218:It is also an important quantity for the
1131:
1130:
1116:
1094:
1066:
1065:
1051:
935:
926:
918:
852:
831:
825:
799:
798:
796:
773:
772:
755:
721:
715:
701:
700:
698:
672:
671:
669:
648:
642:
619:
593:
592:
578:
542:
541:
527:
507:
499:along a path; It is obtained integrating
461:A special type of area density is called
385:
379:
354:
345:
339:
225:
224:
215:
209:
208:
205:
164:
158:
132:
123:
117:
60:
54:
1145:{\displaystyle N=\int n\,\mathrm {d} z.}
453:is the average thickness of the object.
367:{\displaystyle \rho _{A}={\frac {m}{A}}}
145:{\displaystyle \rho _{A}={\frac {m}{A}}}
1281:
883:It is a quantity commonly retrieved by
409:{\displaystyle \rho _{A}=\rho \cdot l,}
226:
210:
36:
7:
318:can be defined by replacing mass by
1331:Nucleation and Atmospheric Aerosols
958:Another closely related concept is
334:Area density can be calculated as:
1132:
1067:
854:
774:
757:
728:
594:
543:
309:of standard sizes ("basis ream").
25:
1308:. Berlin: Springer. p. 470.
437:is the total area of the object,
431:is the total mass of the object,
1161:Areal density (computer storage)
973:
889:Total Ozone Mapping Spectrometer
182:{\displaystyle \rho _{A}=\rho l}
1368:IEEE Trans. Geosci. Remote Sens
1366:-B microwave radiometer data".
1429:"Column Density | COSMOS"
887:instruments, for instance the
813:{\displaystyle {\bar {\rho }}}
804:
706:
686:{\displaystyle {\bar {\rho }}}
677:
1:
1339:10.1007/978-1-4020-6475-3_227
425:is the average area density,
326:, with resulting units of m.
1501:
1198:
1184:
1158:
29:
1445:. Webopedia. 3 March 1997
840:{\displaystyle \rho _{A}}
657:{\displaystyle \rho _{A}}
567:line of sight propagation
69:{\displaystyle \rho _{A}}
1485:Area-specific quantities
1388:10.1109/TGRS.2008.918013
1304:Visconti, Guido (2001).
863:{\displaystyle \Delta z}
32:Density (disambiguation)
1220:absorption of radiation
1012:interstellar extinction
1333:. pp. 1145ā1149.
1293:(2nd ed.). Wiley.
1243:total electron content
1146:
1103:
1081:
950:
864:
841:
814:
785:
744:
687:
658:
628:
608:
557:
516:
410:
368:
235:
183:
146:
70:
1291:Environmental Physics
1249:Snow water equivalent
1147:
1104:
1082:
951:
865:
842:
815:
786:
745:
688:
659:
629:
609:
558:
517:
515:{\displaystyle \rho }
467:columnar mass density
411:
369:
236:
184:
147:
71:
1115:
1093:
1050:
917:
851:
824:
795:
754:
697:
668:
641:
618:
577:
526:
506:
378:
338:
204:
157:
116:
53:
1480:Classical mechanics
1470:Atmospheric physics
1380:2008ITGRS..46.2307M
1171:optical disc drives
879:Atmospheric physics
571:atmospheric physics
320:number of particles
315:area number density
260:superficial density
1155:Data storage media
1142:
1099:
1077:
985:. You can help by
946:
860:
837:
810:
781:
740:
683:
654:
624:
604:
553:
512:
501:volumetric density
406:
364:
324:countable quantity
231:
179:
142:
93:SI base units
66:
27:Mass per unit area
1348:978-1-4020-6474-6
1315:978-3-540-67420-7
1102:{\displaystyle z}
1003:
1002:
941:
911:liquid water path
807:
735:
709:
680:
637:Columnar density
627:{\displaystyle z}
362:
276:density thickness
244:
243:
140:
16:(Redirected from
1492:
1455:
1454:
1452:
1450:
1439:
1433:
1432:
1425:
1419:
1418:
1406:
1400:
1399:
1374:(8): 2307ā2322.
1359:
1353:
1352:
1326:
1320:
1319:
1301:
1295:
1294:
1286:
1167:hard disk drives
1151:
1149:
1148:
1143:
1135:
1108:
1106:
1105:
1100:
1086:
1084:
1083:
1078:
1070:
998:
995:
977:
970:
955:
953:
952:
947:
942:
940:
939:
927:
869:
867:
866:
861:
846:
844:
843:
838:
836:
835:
819:
817:
816:
811:
809:
808:
800:
790:
788:
787:
782:
777:
749:
747:
746:
741:
736:
734:
726:
725:
716:
711:
710:
702:
692:
690:
689:
684:
682:
681:
673:
663:
661:
660:
655:
653:
652:
633:
631:
630:
625:
613:
611:
610:
605:
597:
562:
560:
559:
554:
546:
521:
519:
518:
513:
451:
441:
435:
429:
423:
415:
413:
412:
407:
390:
389:
373:
371:
370:
365:
363:
355:
350:
349:
240:
238:
237:
232:
230:
229:
223:
222:
214:
213:
188:
186:
185:
180:
169:
168:
151:
149:
148:
143:
141:
133:
128:
127:
106:other quantities
104:Derivations from
94:
75:
73:
72:
67:
65:
64:
37:
21:
1500:
1499:
1495:
1494:
1493:
1491:
1490:
1489:
1460:
1459:
1458:
1448:
1446:
1443:"Areal Density"
1441:
1440:
1436:
1427:
1426:
1422:
1408:
1407:
1403:
1361:
1360:
1356:
1349:
1328:
1327:
1323:
1316:
1303:
1302:
1298:
1288:
1287:
1283:
1279:
1257:
1236:body mass index
1216:
1203:
1197:
1189:
1183:
1163:
1157:
1113:
1112:
1091:
1090:
1048:
1047:
1042:(line-of-sight)
1023:accretion disks
1017:
999:
993:
990:
983:needs expansion
968:
931:
915:
914:
881:
876:
849:
848:
827:
822:
821:
793:
792:
752:
751:
727:
717:
695:
694:
666:
665:
644:
639:
638:
616:
615:
575:
574:
524:
523:
522:over a column:
504:
503:
479:
459:
449:
443:is the average
439:
433:
427:
422:
418:
381:
376:
375:
341:
336:
335:
332:
288:SI derived unit
256:surface density
250:(also known as
207:
202:
201:
191:
160:
155:
154:
119:
114:
113:
107:
105:
92:
56:
51:
50:
47:
35:
28:
23:
22:
15:
12:
11:
5:
1498:
1496:
1488:
1487:
1482:
1477:
1472:
1462:
1461:
1457:
1456:
1434:
1420:
1401:
1354:
1347:
1321:
1314:
1296:
1280:
1278:
1275:
1274:
1273:
1268:
1266:Linear density
1263:
1261:Areic quantity
1256:
1253:
1215:
1212:
1199:Main article:
1196:
1193:
1185:Main article:
1182:
1179:
1159:Main article:
1156:
1153:
1141:
1138:
1134:
1129:
1126:
1123:
1120:
1098:
1076:
1073:
1069:
1064:
1061:
1058:
1055:
1015:
1001:
1000:
980:
978:
967:
964:
945:
938:
934:
930:
925:
922:
885:remote sensing
880:
877:
875:
872:
859:
856:
834:
830:
806:
803:
780:
776:
771:
768:
765:
762:
759:
739:
733:
730:
724:
720:
714:
708:
705:
679:
676:
651:
647:
623:
603:
600:
596:
591:
588:
585:
582:
552:
549:
545:
540:
537:
534:
531:
511:
477:
471:column density
463:column density
458:
457:Column density
455:
420:
405:
402:
399:
396:
393:
388:
384:
361:
358:
353:
348:
344:
331:
328:
272:column density
268:mass thickness
242:
241:
228:
221:
218:
212:
199:
193:
192:
190:
189:
178:
175:
172:
167:
163:
152:
139:
136:
131:
126:
122:
110:
108:
103:
100:
99:
96:
87:
86:
83:
77:
76:
63:
59:
48:
46:Common symbols
45:
42:
41:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
1497:
1486:
1483:
1481:
1478:
1476:
1473:
1471:
1468:
1467:
1465:
1444:
1438:
1435:
1430:
1424:
1421:
1416:
1412:
1405:
1402:
1397:
1393:
1389:
1385:
1381:
1377:
1373:
1369:
1365:
1358:
1355:
1350:
1344:
1340:
1336:
1332:
1325:
1322:
1317:
1311:
1307:
1300:
1297:
1292:
1285:
1282:
1276:
1272:
1271:Paper density
1269:
1267:
1264:
1262:
1259:
1258:
1254:
1252:
1250:
1246:
1244:
1239:
1237:
1232:
1230:
1226:
1223:
1221:
1213:
1211:
1208:
1202:
1194:
1192:
1188:
1180:
1178:
1176:
1172:
1168:
1162:
1154:
1152:
1139:
1136:
1127:
1124:
1121:
1118:
1110:
1096:
1087:
1074:
1071:
1062:
1059:
1056:
1053:
1045:
1043:
1039:
1036:
1032:
1028:
1024:
1019:
1013:
1009:
1008:hydrogen line
997:
988:
984:
981:This section
979:
976:
972:
971:
965:
963:
961:
960:optical depth
956:
943:
936:
932:
928:
923:
920:
912:
907:
905:
902:
898:
894:
890:
886:
878:
873:
871:
857:
832:
828:
801:
778:
769:
766:
763:
760:
737:
731:
722:
718:
712:
703:
674:
649:
645:
635:
621:
601:
598:
589:
586:
583:
580:
572:
568:
563:
550:
547:
538:
535:
532:
529:
509:
502:
498:
495:
491:
487:
483:
476:
472:
468:
464:
456:
454:
452:
446:
442:
436:
430:
424:
403:
400:
397:
394:
391:
386:
382:
359:
356:
351:
346:
342:
329:
327:
325:
321:
317:
316:
310:
308:
304:
299:
297:
293:
289:
285:
281:
277:
273:
269:
265:
264:areic density
261:
257:
253:
252:areal density
249:
219:
216:
200:
198:
194:
176:
173:
170:
165:
161:
153:
137:
134:
129:
124:
120:
112:
111:
109:
101:
97:
95:
88:
84:
82:
78:
61:
57:
49:
43:
38:
33:
19:
18:Areal density
1475:Mass density
1447:. Retrieved
1437:
1423:
1414:
1404:
1371:
1367:
1357:
1330:
1324:
1305:
1299:
1290:
1284:
1247:
1240:
1233:
1229:Bone density
1227:
1224:
1217:
1204:
1190:
1164:
1111:
1088:
1046:
1020:
1004:
991:
987:adding to it
982:
957:
908:
882:
636:
564:
484:. It is the
481:
474:
470:
466:
462:
460:
448:
438:
432:
426:
417:
333:
313:
311:
300:
296:square metre
275:
271:
267:
263:
259:
255:
251:
248:area density
247:
245:
81:SI unit
40:Area density
1175:tape drives
994:August 2015
904:radiometers
473:), denoted
330:Formulation
298:" (kgĀ·m).
1464:Categories
1413:-E data".
1277:References
1038:integrated
497:integrated
469:or simply
312:A related
1125:∫
1063:ρ
1060:∫
1054:σ
1033:per unit
1031:substance
966:Astronomy
933:ρ
929:σ
901:microwave
899:-looking
855:Δ
829:ρ
805:¯
802:ρ
767:∫
758:Δ
729:Δ
719:ρ
707:¯
704:ρ
678:¯
675:ρ
646:ρ
590:ρ
587:∫
581:σ
539:ρ
536:∫
530:σ
510:ρ
492:per unit
490:substance
398:⋅
395:ρ
383:ρ
343:ρ
322:or other
282:per unit
217:−
197:Dimension
174:ρ
162:ρ
121:ρ
58:ρ
1449:April 9,
1396:20910677
1255:See also
1201:grammage
1187:grammage
303:grammage
292:kilogram
290:is the "
1376:Bibcode
445:density
1394:
1345:
1312:
1207:ounces
1195:Fabric
1089:where
847:, and
750:where
614:where
465:(also
447:, and
416:where
286:. The
1392:S2CID
1214:Other
1181:Paper
897:nadir
874:Usage
274:, or
1451:2014
1411:AMSR
1364:AMSU
1343:ISBN
1310:ISBN
1241:The
1234:The
1173:and
1035:area
1027:mass
494:area
486:mass
307:ream
294:per
284:area
280:mass
246:The
98:mā
kg
85:kg/m
1384:doi
1335:doi
1222:.
1029:of
989:.
693:as
569:in
488:of
480:or
374:or
90:In
1466::
1390:.
1382:.
1372:46
1370:.
1341:.
1169:,
1018:.
962:.
906:.
820:,
791:;
270:,
266:,
262:,
258:,
254:,
1453:.
1431:.
1398:.
1386::
1378::
1351:.
1337::
1318:.
1140:.
1137:z
1133:d
1128:n
1122:=
1119:N
1097:z
1075:,
1072:z
1068:d
1057:=
1016:2
996:)
992:(
944:.
937:0
924:=
921:P
858:z
833:A
779:z
775:d
770:1
764:=
761:z
738:,
732:z
723:A
713:=
650:A
622:z
602:,
599:z
595:d
584:=
551:.
548:s
544:d
533:=
482:Ļ
478:A
475:Ļ
450:l
440:Ļ
434:A
428:m
421:A
419:Ļ
404:,
401:l
392:=
387:A
360:A
357:m
352:=
347:A
227:M
220:2
211:L
177:l
171:=
166:A
138:A
135:m
130:=
125:A
62:A
34:.
20:)
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