1、 - .=-. . . -. REPORT No. 147STANDARD ATMOSPHEREBy WILLIS RAY GRBGGUnited States Weather Bureau. _- ”=._w“ .a71Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
2、IHS-,-,-REPORT NO. 147.- .,. .STANDARD ATMOSPHERE.By WILUS RAY GBECKL.-. .SUMMARY.Upon the recommendation of the subcommittee on aerodynamics at its meeting O?December17, 1921, the mecutive committee of the National Advisory C!an_mitteefor Aeronautics idoptedfor performance testing Tousmints formula
3、 of temperature decrease with height for obtainingair density at diHerent altitudes.The NatioriaI Advisory Committee for Aeronautics further requested the United StatesWeather Bureau to prepare a technical report. covering the actual observations on the varia-tion of temperature, pressure, and densi
4、ty of the atmosphere for summer, winter, end the year.It has been shown from observations over a long period that up to 10 or 12 kilometersthe mean variation of temperature with titude in the United States is expressed very closelyby Tonssaints formulat=15 0.00652where t is the temperature in degree
5、s centide and Z the altitude in metem. From 12 to20 kilomote the temperature is approximately constant at 55C. as shown by Table 1( 67F.in EngLish units, TabIe 4) in the following report which gives the mean observed values of pres-sure and temperature at various altitudes for the Utited States (lat
6、itude 40) for summer,titer. and mean s-rmual conditions. The vaIues wdculated from Toussaints fornda aregiven in Table 3 (Table 5 in Ethat is to say, at no time or place do “standard” or avere conditions of all of the meteoro-logical ekments at td.1altitud= simult.anecmdy occur. Nemrthekss it is pro
7、per, and. in certainfiekls (wpeciaLly those of aviation and ordnance) it is nary, ta adopt so-calkd “standard”dues, and it is desirable to kve the represent ss osey as possibe true mean vd”um in. .lTblsre k in part bsed upons UnUtM(IAnAmy tmd tnblcsand curves, based upon them data and giving standar
8、d conditions, huvc been prepared tmd madiscussed in the following paragraphs.DATA USED IN THIS INVESTIGATION.Free flight investigations are conducted at th? present time almost wholy a 3fcCookField (Dayton), Ohio; P7ashinon, D. C.; and Langhy I?iold (Hampton), Va. TIM principalartillery testing stat
9、ions or proving grounds are at Aberdcon, ?dd., rmd Daldgrcnj Va. ill ofthese places are located near (less than 3 from) latitu Mount Weather, Vu., latitude 39 04; and Royal Gmter, Ind., latitudo 4053. Ithas therefore seemsd proper to use the data from these stations as a basis for establishing astan
10、dard atmosphere which shall best fit practical needs, so far as the United States is concerned.Accordingly, mean summer, winter, and annual temperatures for different Iovols up to andincluding 5 kilometers have been computed from those data. These mean -mluos may boaccept ed as representing very clo
11、sely actual average temperature conditions at Id itudo 40,since the values at the three stations agree well among thernselws and are, morcovor, basedupon a large. number of daily observations covering. pctriods of from throo to fivo yoms. Itshould be borne in mind that as the distance from latitude
12、40 increases, tho Variation from thmomean values likewise increases. The yariation is greatest in winter, -whenit amounts to about1 C. per degree of latitude at the surface, diminishing slightly at higher Ievels.For levels above 5 kilometers it has been possible to use the results of sounding balloo
13、nobservations at Fort Omaha, Nebr., latitude 41, 19, and St. buis, MO.) latitudo 38 38.Here again the results may be considered as representative of conditions at Iatitudo 40.Unfortunately, the number of observations upon which the moans are based is small, but itshodd be remembered that smaller var
14、iations occur in the temperature gradients at greatheights than at 10WMlevels and hat therefore a smaller nurgber of observations suffices togive very satisfactory information at those levels. .The observations used are thoso mado atFort (hnaha, February 8 to March 4, 1911; July 9 to 22, 1914;4and a
15、t St. Louis in 1904 to 1907.*For Mount IVeatbrtheIwxnL%b) al,m ,.tFat-OmAe._ . _ 17 17 M St. IA0i9-I WfntiFart Omehk_-_ I .;iT+ ; :St. IOis.-.-.1.1 1 - - . . . . . . . . . . .1 .From this table it is seen that most of the observations were obtained at Fort Omaha;those for the summer were made in the
16、 hottest month of that season and those fo the winterin the latter part of that season. Hence, in each -e the values are somewhat higher thantrue seasonal means. Thus at 5 kilometers the summer vrdues are 3-5 C. higher than thosedetermined from observations with kites, and in winter they are 1.5 C-
17、higher. These differ- . .“ .:-ences have been adjusted by applying to the means at 5 kilometers obtained from kite observa-tions the gradients computed from the sounding balIoon records. This procedure has beenfolIovredin determining the mean temperature at all sJtitudes up to the base of the strato
18、sphere.At higher Iemls, up to about 2CIkilometers, the mwm values in both seasons are practicallyconstant at 55 C. There may be a seasonal difference, but the records do not show it, andin any event the value of 55 C. can hardly be in error more than 2.5 C., except at 19 and 20kilometers in summer w
19、hen there is a tendtmcy to increasing temperatures. For the presentpurposes it has been deemed sufficient to use the constant value, 55 C., from the base of thestratosphere up to 20 kilometers, the highest level considered-eRESULTS.Final results are showm in Fire 1 and in Table 1, valum in the latte
20、r being expressed tothe nearest hdf degree c-entigrade. The yearly vahm me the means of the two seasons, sinceit was found that the mems for all four seons me almost exactly the same as these.Vapor presmu-e means have been determined in the same way as have the temperatur interv beingdetermined from
21、 the mdues given in Table 1. Corrections have been made for humidity andfor the variation of gravity with altitude and latitude. The reds up to 5 Hornet-em aggeeCIosely, within 1 mdlibar, with the means of the actmdly observed values themselvw. For -.highw leve.Is this comparison is impossible, sinc
22、e the temperatures used, as already explained,me not those actually observed. The computed values of pressure for summer and titer areshown in Figure 3; the annual curve k not been drawn, but would lie midway between theother two. Values for the two seasbns and for the year also are given in TabIe 1
23、 and areexpi+med in both millibars and milkuetera, to the nearest half in each case.i71th the data discussed in the preceding paragraphs and prwented in Table 1, it hss beenpossible to determine corr=pon air densitia for each Ievel. The values in the fit columnunder “Density,) Table 1, have been com
24、puted from the formulab 0.378e =#=Tin whichP= dity =pr=d in percente of st-mdard density,it and e= barometric and vapor pressures respectively, in millibars,T= tiperature, in “A,and K= a constant, depending upon the conditions of presure and temperaturethat exe accepted as standard, in this case 101
25、3.3 fibirs, and 0 C.,or K= 0.26942. .-fItshotdd not belnkrredfromthfsetatementtlmts.ccmsbmttemperetorechbmtsY Cdl befoud athekcbvMOHkmeters. On the_-ather handj the few okcmtkm.s thne fiu md$ mcdy b. mmmeir, mow fncmsstemp+5T!tuKS with hdgilt,r- W.Ine3between w c.and- c.w25tomknamk. -.33 1-. - .-.1.
26、 sure, in.FIG. 2. Mum frondr vapor prawurcs al abckt Ialltudc 40”N,in the Urdted Etahs., , I I tni I I,4 , ,. ft.It?/6Densify, kg./cu.m.FIG. 4. Afesn frwair densltios at about latitude 40”N. In the Unitedsat=.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from I
27、HS-,-,-STANDARD ATMOSPHERJL 403 “-The values in the second column have been obtained by multiplying those in the first by1.293 kilograms per cubic meter, the density at 10E3.3 millibam and 0 C., or p =p X 1.293.These values for the summer and winter are shown in Figure 4; the annual curve, if drawn,
28、would lie very nearly mid-way between the other two.In order to facilitate comparison with densities that have been computed for other pintsof the worId Table 2 has been prepared. So far as known to the writer, these are all that havebeen published thus far. b most oases only annual values have beei
29、i givem These are pre-sented in Table 2 in suoh a way that the latitudimd variation may be seen at a glsmce. Aa71 striking feature is the essential agreement in the density at about 8 kilometers both in summerand winter tmd at all latitudCOMPARISON WITHVALLIESCOMPUTED FROM TOUSSAINTS FORMULA.TabIe 2
30、 aIso contains, in the Isst cohmm, the vshms computed from Toussaints formula.This formula has been discussed in a previous paper. (See footnote 4 in the t.abIe.) Briefly,Toussaint, using as a basis the available free-air data for Europe, has proposed the adoption,by all oountries, of a “law” of lin
31、ear deeresse of temperature with altitude, stinting at a tem-perature of 15 C. at sea level and attaining 50 C. at em altitude of 10,000 meters. This“law” is expressed by the formulat= 15-0.00652,in whicht= temperature in “C.,tmd Z = altitude in meters.Using the temperatures at various leveLs, as de
32、duced from this formula, and assuming thatthe atmosphere is dry, and that gravity remains constant, the author has computed values ofpressure and density for ditTerent heiglits up to 10 kilometem. The restdts are present inTable 3, in which are repeated the density values given in the last cohmm of
33、Table 2.Concerning these figures, Tousssint says:It hasbeen found preferable to take a linem law “oftemperature decrease rather than to seek an equation approxi-mate to Frofe3wr Gambas curvq for the foIIowing reaxm:Inca-da to detine the etandard atmcspher% whath neededienotan exact reprmentation of
34、that curve, but merelya lawthat can be conveniently applied andwhichieauSicientIy in concordance with the means adhered to. BY thismethod, correction due to tempaature wiJl be aa small ae bIe in caicuhtiona of aiqdane performance, aud willbe easy to calculate. The proposed Iaw seems Iikely to rdize
35、e-d condition.The dmiation ie of some alight importanceonlyat altitudesbelow1,000 mekrs,which altitud= areofIittleinteatin ti narS by W. J. Huraphmy thosefor winter to December, January, and February; and the annual means to farh, April, May,September, October, and November.RESULTS EXPRESSED IN ENGL
36、ISH UNITS.For the convenience of those who prefer Engli+ units, Tables 4 and 5 have been prepared.TabIe 4 corresponds to Table 1 and TabIe 5 giveyEnglish equivalents of the values computedfrom Toussas formula (Table 3). Altitudes are expressed in feet, pressures in inches, tem-peratures in degrees F
37、ahrenheit, and densities in percentages of standard (dry air at 29.92inches pressure, 32 F. and latitude 46, = 0.08071 pound per cubic foot), and in pounds pmcubic foot.LATITUDINALVARIATIONlIYFREE-AIRDENSITY.As a matter of general interest only, Table 6 has been copied from Linkes discussion ofdensi
38、ties in aIl parts of the world. The means given have in large part been esthated by extra-polation and interpolation, based upon all available data. Here again is strikingly shown thesubstantial agreement at about 8 k.iiometers.Provided by IHSNot for ResaleNo reproduction or networking permitted wit
39、hout license from IHS-,-,-STANDARD ATMOSPHERE. 4U5LMEI.Jiean/ree+zii barometric anduqm prezmuea, tempmtum ad a%ndia at ubout lathde iii the Ukiied S;20k! k:.- . . -. -._. . . . . . .-.- .- . . . . . . . .-. -. . -. . . . - - .- -. .- . . . . . - . . .-. -WINTERo”-yj-40-s.0-7.09.01L5m. 52L5*5-4L046.
40、5=%!-540-m. O=:-65.0-55.0+0+0-55.0%!Lo25NL5;:-.-. .- - . .-.-. .-,-ACm-mLJ1IL59.5!.-. . .-,-.,.-, ,.- .- .L Ii5L123:%a975:E.ml.mA53.ss7.m-m.4M:E:%.m.17a.Ku.120.Is.I.0%tL240L li - -. :- .=-w-. -y-. -.=_.- - .:-.42-. .,- :- -. . _ .-“.:”-. -?_-. . .: -. L-. 7.-. =- -=.-. . Provided by IHSNot for Resal
41、eNo reproduction or networking permitted without license from IHS-,-,-408 REPORT NATIONAL ADVISORY COM.MIfiEE FOR AERONAUTICS.TABLE 4.Mean j%w-air barometi and v.awr premme, tempmturee and denadh, at abatd lutiudr 400 in the UN;(Id StatesEnglM measww-(lmtinued.Iuchg2%9527.91am23.9.48amam7.666.W6.286
42、.724.518.552.80“F. IrtCht6.62.6 (lZ4543.5 .20.Z1M .2346.0 .2U42.5 . ls-4CL5 .168s.o .14HO l!.82.6 .11.2%5 .OJ23.6 :$.23.0m o .0316.5 .05I&om.o :%&5 .09.02:i .015. o .o1-9. o . . . . . .-lS-o . .I-16.5 . . . . . . -XL6 . . . . . . . . . .-24.0 . . . . . . . . . .-27.6 :. . . . . . . . -8L0-3*O :-37.5
43、 l. . as . . -46.0 . .6L o . .-6$.0 . . -l n . . . .-64.0 . .2gg . . _. . 07:0 . .67.0 . ._m.o . .I 1TABLE b.Mean free-air bmxmh+c prwwee, tempmztures and densi.tiee, computed jmm TOUW&U t fonnubt- Enyidtnlea.eura .AItitudcmean 9elevel.I_?rewlre.Donslty.pmy-rmmdnl5a. -,. .,- -.Provided by IHSNot for
44、 ResaleNo reproduction or networking permitted without license from IHS-,-,-.-STANDABD ATMOSPHERE. 409TABm (1.-%nfree&denadh, kkyam per cubic meter, at wriom Laiitude-sandaltitwh aa annputed by hnzfinh.1 Latitude. I. . *-.=-“-.!- .-. . -. . . .T:-.“-“-y.:, ”_-= -+-. .-,-+-. - :*=.-:-K-4-.-. i -a71 %=71ber die.kftdkhte. BeItrKgg zor PItP& der Men AtmmphKre. W Band. Heft 3-4. 191-IW, 1919.Provided by IHS Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-
