JULY 1940 MONTHLY WEATHER REVIEW 185
Nov. 30, 1935 ...__________
Oct. 10. 1936. ________._..
Dec. 23, 1936 _______.__.__
Mar. 10,19&q ...______ ____ Oct. 25,1933 ..___._______ Oct. 26, 1938. ..______ ____ Oct. 29,1938 .._------____
Oct. 30, 1939. __.__.__ ____ Nov. 10, 1938 .__....._ ____ Nov. 21, 1938 .__._.______.
Nov. 28, 1338 _______
~
_____ Nov. 30,1935 .______._____
Dec. 6. 1038 ..______._____
Jan. 20, 1933 ______________
TABLD 1.-Comparison of mininiu )tz temperature observations at Belle Chasse, La., and 9 additional ground-level stations, with the minimum at New Orleans Weather Bureau ojice as the basis for comparison, on 14 dales when Belle Chasse was 80' or more below
TABLE 2.-Tabztlation of daily differences in minimum temperature at Belle Chasse compared with those at the Weother Bureau O&e in New Orleans. (All temperatures at Belle Chasse are lower than those with which they are compared.) Based on 44 months o j record; New Orleans 193'6-39
I I
Mini- Belle Cbssse Delta Farms Houma mum tempera- ture,New Mini- Differ- Mini- Differ- Minl- Differ- Orleans mum ence mum ence mum ence
~---________
0 0 D 0 0
40 28 20 r ________ 36 13 64 43 21 P.. ._____ 49 15
50 26 24 9 .-_____- 33 17 OF. 68 4.5 23 r ______.. 57 11 January ._____________________________ 4
55 32 23 38 10 39 16 February ________._____.._.__-------. 4
55 34 21 36 19 40 15 March ....-.-...-.-.------.--------.- 7
50 30 20 44 15 43 18 dpr il..----.-.-.....----------------- 7
60 38 22 44 16 42 18 May .__.______
~
__.________.______.___ 7
48 26 22 34 14 32 16 June ___.__.___
~
____________..________ 8
40 16 24 23 17 24 16 August ......-...--..---.--------.-.- 7
43 18 25 24 19 27 18 September.. - ____._._________ ____ ____ 7
47 23 24 20 18 32 15 October ..________._.________________
~
0
47 21 20 ? --____._ 28 18 November ________..________________
~
8 7
52 31 21 36 18 36 16 July ....._.___
~
.__.____.___________.- 6
~
- - - - - - December. - - -
~
___________
~
__________
Date
I
Percent
16
17
35
37 45
33
12
18
28 42
37
34
30
~.
Month
Annual average -__-__ - - - .__ ___
~
Averaredepression
I 1 1 1 1 1 1 of minimum be- low New Or- leans _..__________ __________ ________ 22 ________ 17 ________ 18
7.6
Percentage of daily observations with the minimum temperature
I Average I at Belle Ch-
8
5
1 0
0 5
I9 22
18
monthly depression of minima 10' or more 15' or more 20' or more at Belle below New below New below New
1
Chase
1
Orleans
1
Orleans
I
Orleans
0 0 0
0
0
0 5 1 4
P e r m t Pcrcrnt
16 0
j/ P
RADIATIVE COOLING IN THE LOWER ATMOSPHERE
By WALTER M. ELSASSER
[California Institute of Technology and U. 8. Weather Bureau, August 19401
The writer has recent1 developed a gra.phica1 method
atmosphere (1). This is a modification of the graphical method introduced some years ago by Miigge and Moller
(2). In this method moisture and temperature values of a given atmosphere are plotted on a printed diagram (later referred to as Radiation Chart) and the radiative flux a t any level can be obtained by evaluating an area on the
chart. The results given below represent the first prac- tical tests of our chart. A comprehensive paper covering the theory of the chart has just been published (1) and we shall therefore omit references t.0 the theoretical founda-
tions of this work and confine ourselves to a conimunica- tion of the results. *
for the determination o 9 radiative heat transfer in the
I. FREE AIR COOLING
We used airplane observations of free air moistures and temperatures. The stations selected (with the exception
of Fort Smith, Northwest Territory) are located in two north-south cross sections over the United States. The
mean values of February 1937 and of August 1937 served
ns basis for these calculations. The cooling calculated represents the mean cooling in layers 1 kilometer thick due
to the long-wave radiation of water vapor (the cooling due to carbon-dioxide radiation is found negligible). The
procedure of-evaluating the cooling was as follows. First,
specific humidity (with a pressure correction applied, see
below) was plotted against pressure. The points were joined by a curve and the total amount of moisture between successive levels, 1 kilometer distant, was determined by
means of a planimeter. These values of total moisture were then plotted against temperature on the radiation
chart. It is usually possible to plot, on the same chart, curves corresponding to several or to all levels of one
station. The area contained between curves representing
successive levels measures the heat loss of the layer be-
tween them; this loss divided by the heat capacity of the layer gives the net cooling.
*Part of the calculations WBS carried out by A. C. Qfbson of the U. 9. Weather Bureau, now at Jacksonville. Fla.
There is still a certain doubt about the manner in which
the air pressure affects the radiative properties of water
vapor. According to a theoretical formula (3) the
absorption should be proportional to the pressure, while
F. Schnaidt (4) derives from measurements of G. Falcken- berg (5) the result that the absorption is proportional to
the square root of the air pressure. The latter view is sustained by other, yet unpublished, experiments carried out by John Strong a t the California Institute of Tech-
nology. We therefore used the square root pressure
correction in our computations. The figures in table 1 represent mean values of the
cooling in layers I kilometer thick. It is to be under-
stood tthat these layers have nothing to do with the division of the atmosphere in layers in the manner of
Simpson (6). The latter division originates from a method of approximation where differentials are replaced
by finite differences. Our figures, on the other hand,
represent rigorous solutions of the differential equations
of radiative transfer, once the absorption coefficients of water vapor are given. It would be possible to calculate
the "local" cooling a t any given level, but the determina- tion of the mean cooling of a layer of reasonable thickness
is less laborious and also much more accurate. The values given in table 1 are in degrees centigrade per day.
All the cooling values contained in table 1 are plotted in figure 1 with the clecadic 10gnrit~hm of the specific
humidity as abscissa. The oblique line represents the
empirical relation
(AT)sOv=1$.2 loglo W (1 1
The two dashed lines are set off from the main line by 0.4'
on each side. It is seen that the large majority of the points falls within these boundaries. The major devia-
tions seem to occur in the lowest kilometer; the points
representing these layers are inclicated by rings in figure
1. The cause of this decrease in cooling is presumably
to he found in the relatively lower mean temperature of
the lowest kilometer due to the influence of the nocturnal
MONTHLY WEATHER REVIEW JULY 1940 186
ground inversion. Caution should therefore be used in the application of formula (1) to meteorological problems. We think, however, that (1 ) is a workable approximation
for average conditions in middle latitudes and in the lower middle troposphere. It should not be extrapolated
to other conditions without new checks by direct applica-
tion of the chart.
11. CLOUD COOLING
If the curves representing the moisture-temperature
relations are drawn on the radiation chart, it is easy to determine the amount of heat which a black surface located
at any level of the atmosphere gains or loses if it radiates upward or downward. As the base and the top of ,z
cloud represent such black surfaces one can readily obtain the mean cooling of a cloud. There is usually a gain of
heat a t the base and a loss a t the top of a cloud, the latter
being by f a r the larger. In table 2 figures representing
the gain a t a cloud base and the loss a t a cloud top located
a t the levels indicated are given in calories per 3 hours.
- 3.5 AT
-3
-2.5
-2
-15
.
W
2 5 I O 15
FIGURE 1.
It is seen that the net loss for a cloud of 1 kiloineter thick-
ness runs very near to 30 calories per 3 hours; only for
clouds in the lowest kilometer the values are somewhat
lower. The following formula gives a fairly good estimate of the cooling of a cloud under avercige conditions:
Here d is the thickness of the cloud expressed in millibars
and the cooling is given in degrees centigrade per day.
Formula (2) applies under about the same conditions and the same restrictions as fomula (1) for the free-air cooling.
It must be said here that t'he moisture distribution in the mean soundings is of course such that no clouds would
be expected, as the relative humidity nowhere reaches
100 percent. Our calculations show, however, that the
cooling values are rather insensitive to small changes in
moisture and the values in table 2 would therefore only change by a few percent if in place of the mean soundings
we substituted soundings in which the humidity actually
goes up to 100 percent a t the cloud. A similar argument may also be applied to the free-air cooling as given in
Table 1. If we wanted to obtain the actual mean cooling, we would have to use the mean of only those soundings
which correspond to a cloudless sky. As this would not
be very different from the over-all monthly mean, we introduce only a small error by using the latter throughout
our calculations. Table 3 contains the values of the heat loss a t the ground
for a cloudless sky computed in the same manner.
111. RADIATIVE HEAT TRANSFER I N NOCTURNAL GROUND
INVERSIONS
In the calculations for table 1 it was assumed that the ground itself has the same temperature as the air near the ground whose temperature is indicated in the soundings.
Actually, during the night the ground temperature will sink below that of the air in the lowest layers and this phenomenon will intensify the formation of ground inver-
sions. Calculations which give the order of magnitude of this effect are summarized in table 4. It was found con-
venient to calculate for a number of typical cases rather than for selected individual records. The first two lines
of table 4 give the temperatures and specific humidities in
the air near the ground for which the calculations were carried through. Assume for a moment that the ground and a layer of air have the same temperature. A certain
amount R of radiation emitted by the ground is absorbed by the air near the ground. If there is a temperature
difference between the two radiations, a net flux of heat
dR
dt F=6T -
will take place. The quantity dRldT can be obtained from the chart (it is equal to the area of a, strip bounded by 2 isotherms distant by 1' and by 2 moisture isopleths
which correspond to the bottom and to the top of the
lager). Since t'he layers are rather thin, it is necessary to
calculate also the heat flux due to the radiation in the carbon-dioxide band. Schnaidt (4) gives a curve for the
absorption of CO, radiation as function of the thickness. The experimental data were corrected by him so that this
final curve refers to a condition where both the emitting
black body and the absorbing layers are a t the same tem- perature of 0' C. According to Schnaidt, about 8 percent of the total radiation of a black body of 0' C. is absorbed
by the COz in the first 100 ni. of air and about 6 percent more by the COz in the next following 300 m., while
beyond this distance there is very little additional absorp- t'ion. These figures refer to the absorption of a straight
beam ; the corresponding values for diff use radiation are
obtained approximately by taking half the thicknesses for the same percentual absorption. Let R' be the amount
of radiation in the CO, band which is exchanged between the ground and any layer of air of the same temperature
as the ground; further, put R'=a I' where I' is the spec- tral intensity of black body radiation a t the center of the
C02 band and a a numerical factor. We have then for the heat t,ransfer due to carbon-dioxide radiation
dR' dT' R' dT'
dT- dT- I dT F=8T-- -6T.a --8T-, . -
Now the quantity dI'1I' dT ca.n inmediately be caacu-
lated from Planck's law while R' is given by the figures
quoted above. We now calculate the net cooling of the air which will be
(3) Cooling=
where Cis t.he heat capacity of t,he layer. We assume that the layer is homogeneous in temperature; then 6T repre-
sents the difference between the temperature of the layer
JULY 1940 MONTHLY WEATHER REVIEW 187
and that of the ground. The numerical result's obtained
from formula (3) for variGus temperatures and corre-
sponding moistures are suinrntirizod in t,able 4. The values given in the last two lines are the values of the
factor of 6T in (3) ; multipliec! by 6T they give the aclual cooling in these layers in an iilterval of three hours. The
same figures can of course also be applied to compute the
radiative part of the heating of the air near the ground during the day when the ground temperature is higher
than the air temperature. The results contained in table 4 indicate t,hat radin.tive
exchange of heat between the ground a.nd the at.mosphere
is conwntrated in the lowest 50 mete,rs and is very small above t8his height,. The observed ground inversions are
often of the order of 1 kilometer a.nd if tho tot8al heat
exchange for both layers (which is between 0.3 and 0.5
calorie per degree temperatwe difference of air a.nd ground)
is distributed over t,he height of the inversion, t,he resulting decrease in tcmpera.ture is estreme!y small. Only during
the polar night where the ground teniperature can fall
much below the tempera.ture of the air, does t,his mecha- nism of radiative transfer produce an appreciable effect,
as hes been pointed out by Weder (8). We must con- clude that the ordinary nocturnal inversion is almost
exclusively of turbulent origin so far as the transfer of heat from the ground to the air is concernecl. It is of
coursc of radit-dve origin in the sense that the heat loss
of the ground itself is of a purely radiative nature.
IV. CONCLUSIONS
The results given above show that the radiative cooling in the free air an.d in absence of clouds is confined within
rather narrow limits. €toughly, i t is of the order of l o
per day in air mmses of polar type and of t,he order of 2'
to 3 O per day in air masses of equatorial type. Further-
more, i t appears clearly t.hat thcre is no indication of a heating of the atmosphe.re by radiation. With r e g d to
long-waae mdiicrlion the atmosphere .is a cold SOUTCC throu.gh-
out. This result has a.lreadp been reached by Mugge and Moller (2) and by Albrecht (9). Apart from the heat of
condensation, all the heat. lost by radiation of the atmos- phere must therefore be supplied by turbule.nt exchange
and by convection (frontal, cyclonic, and local). i t ma,y
appear ra,ther siirprising a t first sight that the lapse ra,te
in t,he free atmosphere is not much more frequently
superadiabatic and that local convecti.on does not play a much larger role than is tictually observed. In this
connection we might notice, however, that. the rate of
cooling above 2 kilometers decreascs sten.dily with height and we might presume that this decrease continues
beyond 5 kilometers, where our calculn tions end. In the
course of several days this must lead to an appreciable
stabilization of the lapse mte in the middle troposphere.
Since radiative cooling acts continuously everywhere, it probably constitutes also itself the major stabilizing factor
in t8he atmosphere. The work on the radiation chart referred to above, and
the present investign.tion, were carried out with financial
assislance from t,he Bankhead-Jonw research fund of the
United States Department of dgriculture.
BIBLIOGRAPHY
(1) Papers delivered at the Toronto Meeting, August 1939, of 6he Quar. Jour. Roy. Royal Met. SOC. and the Am. Met. SOC. Met. Soc., vol. 66, Supplement, 1940.
(2) R. Miigge and F. Moller, Zeits, j . Geophya. 8, 53, 1932; Beitr.
(3) W. M. Elsasser. MONTHLY WEA. REV. 65. 323, 1937 and 68, Phys. fr. Atm. 20, 220, 1932.
._ 175, 1938.
(4) F. Schnaidt. Gerl. Beilr. z. Geoohvs. 54. 203. 1939.
(5j G. Falckenberg, Meteor. Zeits, '53; 172,-1936, ~u d 55, 174, 1938.
(6) C. G. Simpson, Mem. Roy. Met. SOC. 3, No. 21, 1928. (7) W. M. Elsasser, Bull. Am. hfet. Soe. 21, 202, May, 1940. (8) H. Wexler. MONTHLY WEA. REV. 64, 122, 1936. (9) F. Albrech't, Zeits. f. Geophys. 6, 421, 1930.
TABLE 1.-Cooling of 2-km. layers i n ' C. per day for cloudless sky- monthly means
Station, month I Qrd. I 1 km. I 2 km. I 3 km. I 4 km. I 5 km.
Fort Smlth, Northwest Territory,
Temperature. . . . - - - __
~
- __ ______ Speciflc humidity _.__ __ _________
February 1937:
Cooling.. . . . . . . . . . . . . -. . . . . __ Fargo, N. Dak., February 1937:
Temperature. . . . - - - - - __ ________ Specific humidity .-.... _________ Cooling ..-. . . . . . . . - -. . -. . __ Omaha, Nebr.. February 1937:
Temperature . . . . - -. -
~
- - - - - ._ - - 6 eci6c humidity ____.
~
_________ doling.. . . .-. . . . . . - -. . . . . ...__.
Oklahoma City, Okla., February
Tempernture . . . . - - - - - - - - - __ - - - - Speciflc humidity _________._.___
Cooling ... . . . . -. . . . . - - -. -. . . . . - San Antonio, Tex., February 1937:
Temperature. .
~
- - - __ _____ ______ SpeciEc humidlty ___________.___
Cooling. .__.__. . . -. ___._. ...._..
Sault Ste. Marle, Mlch., February
Temperature ....--_---._.-...-. Speciflc humidity _______________ Cooling ___..._.. . . ______________ Detroit, February 1937:
Temperature. . . - - -
~
____ __ - ____ S eci6c humidity ...-. __ _____ -
Tern rature ._.________________
Spec& humidity. ______________ Coolin? ........ ~. .__.___.. . . ____
Temperature.. . __ - - - - _. - - __ S eci6c humidity _______________ doling ...-. . ... ~. . . . . . . ____. . ..
Montgomery, Ala., February 1937:
Temperatu re.....---.---------- Speciflc humidity ._____._______.
Cooling . -. -. . . . . . . . . -. . . . . ___.
Temperature. . -. . . - - __ __ __. ..
S eclfic humidity .______________
Tem erature _._______________..
SpecfBc humidity _____..________
Coolina ..-. ___ ___ __._. . .
~
_______
Temperature .....-------------.
Specific humidity _______________ Cooling ....-. . .. .. . . . . . _________
Temperature . . . - ___ - __ __ __ __ __ SDeciflc humiditv _______________
1937:
1937:
2 . ooiinR .... -. . _...__. . . . _______ Dayton, Ohio, Febmary 1937:
Nashville, Tern., February 1937:
Penscola. Fla., February 1837:
2 . ooling.-. . . .--. .... . -. .________
Miami, Fla., February 1937:
Farpo, N. Dak., August 1937:
Omaha, Nehr.. August 1937:
Coolinp . . . . .--. __ .....-
Oklahoma City, Okla., August 1937:
Temperature. . . - - - - - - - - - - - __ - - fipedfic humidity ___________..__
COOhlR ____ . . ___ ...- .. __. . ..._._
San Antonio. Tex.. August 1937:
Tempernture .....-----.-------- Specific humidlty _______________ Cooling . ~. .~ __._ _.__._
fiault Ste. Marie, Mich., August
Temperature.. - __ __ - - - - - - - - - - Spcci6c humidity .______________
Cooling.. . . . . . . . . - - - - - - - - - __ - - - Detroit, August 1937:
Tem~rature Speciflc humidity _______________ Coollng ...-. . .-. . . __. . - _________
Temperature. -. . - - - __ __ __ - - __ - - Sprc~tlc humidlty _______________ Coolin? .-. . --. . . ___ .~ ___. ______
Temnerature . . .- - - - __ __ - - - ___ Spec160 humldity _______________
1937:
Dayton, Ohio, August 1937:
Nashville. Tenn., Angust 1837:
Cooling _____..--_ * ---_..__-- ---_
-23.3 -16.1 -16.7 -21.4 -25.6. .5 1 0.7
.Q I
1.1 0.9 .e l 0.5
.(I -
-16.5 -11.0 -11 0 -14.9 -23.6
.a 1 1.4 I 1:3 I 1.0 I
1.8 I 1.9 I 1.6 I 1.3 I
.6 I
.g I
0.7 1.3 1.4 1.1 0.5
-7.3 -6.0 -6.8 -10.9 -16.3
1.0 0.8 1.3 1.2 1.1
-10.1 1.41 -9.5 1.61 '
1.0 1.0
2.31 1.2 2.11 l.1
2.51 1.3 2.41 1.3
-3.6 -4.4
-2.4 -2.9
1.8 1.6
1.9 1.7
1.3 0.8 0.9
-6 7 -109 -16 1
114 I 112 I 1.2 1.0 0.9
1.61 1.2 1.21 0.9 1.11 0.8
19 I
-4.6 -8.7 -13.8
- 1 -4.4 -9.4
i4 1 1.7 1 1.3 I 1.8 1.4 1.1
1.3 1.3 1.2
:::I :::I 45:; I ?; I -E I 1.9 2.2 2. 1 1.6 1.8
2.7 3.0 2.6 2.6 1. 7
23.1 14.41 24.7 12.41 19 9:21 5 12.6 7.21 6 4181 0
2 8 3.2 2 8 3.0 2.6
24.6 14.71 :::!I %;I
2.17 3.1 3.4 3.5 2.5 I I
E:: I 'E I
1;::
I :::I 3":; I :;:I
2.8 1::: 2.7 I 1;:: 2.5
I :::I 2.4 2 1.8 I
2.4 3.0 2.7 2.5 1.9
2.6 3.3 3. 1 2.5 1.6
E:: I ;;:: I 1;:: I ::: I ::; I 2.a 3.0 2.9 2.8 1.8
- -
-25.8
.4
-22.9
.6
-16.0
.8
-8.2
1.6
-27.4
.5
-21.9
.7
-19.8
.9
-15.1
1.0
-10.9
1.0
-8.8
1.6
-4.0
2 7
-3.1
a 7
-. 7
3.2
-1.8
3.1
-1.0
2 7
-4.1
2.0
-3.2
2.3
-1.4
2 2
-1.6
2.6
188 MONTHLY WEATHER REVIEW JULY 1940
Montgomery, Ala., August 1937: Temperature. ................... Specifichumidity ............... Coolinc. .........................
Tem rature ................... Sp&c humidity ............... Cooling .........................
Pensacola, Fla.. August 1937:
TABLE 1.-Cooling of I-k,in.. layers in C. per day for cloudless sky-
monthly means-Continued
:::I :::I 2.3 2.4 2.3 2.2 2.0
$1; I ?i:: I 'i:; I E:: 1 !:! I -k$ 2.2 2.8 2.4 2.3 2.1
TABLE 2.-Zleat gain at cloud base and heut loss at cloud top in calories per cm a per 3 h.ours-same mean monthly soundings as table I-Con.
7.7 35.3
10.2 33.5
IO. 2 37.1
12.7 35.8
Gain base ........................... Loss top ............................
Gain base ........................... Loss top ............................
Gain haw.-. ............................ Loss top. ...............................
August IO3i:
Miami. Fla.: February 1937:
2
1.6
21.7
.9 3 .0
Station 1 lkm. 2km. 3km. Station, month
31.2 2.11 34.8 4.5
4.6 26.4
3.6 30.7
7.7 30.2
6.3 33. 1
TABLE 2.-Heat gain at cloud base and heat loss at cloud top in calories per cni' per 3 hours-same mean monthly aoundings as table I TABLE 3.-Nocturnal heat loss of the ground in calories per cma per 3 hours for cloudless sky-baaed on same mean soundings as above -
5 km. 22. 8
24. 0 19. 1
27. 3 18. 0
27. 5
17. 9
21. 4
18. 8
28. 8 18. 6
26. 8 19. 6
26. 5 17. 4
26. 9
18. 2
26. 5 18. 3
19. 7 15. 9
19. 3
1 km.
-
-4.0
29.0
-3.3 29.3
-2.3 27.7
-1.0
P I . 1
-1.0 24. 2
-1.3 32.2
-1.0 23.8
-2. 1 211.6
1.0 25.0
-. 3 30. 1
-1.4 28.3
.5 30. 1
n 26.6
.3 28.9
-I . 6 25. 5
1.3 30.9
.8 23.3
1.0 31.7
2.0 22.9
2 lon. 4 km. 3 km. Station
Fort Bmith, Northwest Territory: Februar]
- L_
1937: -3.2 31.8
-3.0 33.2
1.6 32.8
-. 2 33.0
2.9 28.9
-. 1 36.8
3. li
28.7
.3 33. e
6. 1
29.8
1.1
32.1
2.3 31.7
1.9 32. I
4.0 31.0
1.4 33.2
2.9
31. I
3. 1
4.5 28.7
3.3 35. a
5. R 27. 0
34. a
-0.2
31. 1
-. 6 33.9
6.9 35.8
2.4 33.9
e. 8 33.7
3.8 38.9
7.4 33.2
3.0 37.3
8.6 33.9
3. 5
33.0
5.6 34.7
4.4
33.0
7.1 35.0
4.0
34.2
5.8 36.5
5.9 35.7
7. R 33. 3
5.2
37.3
8.4 30.9
2 4 30.7
3.6 33.6
10. 1
37. R
K. 0 33.3
10.6 36.8
7. 3 37.3
11.4
38.6
7.0 33.6
11.9 37.9
6.8 32.0
8.9 37.7
7.6 32.0
10. 1 37.7
7.2 33.3
9.4 39.3
8.7 36.0
IO. 7 37.5
8.0 37. 8
10.8 34.1
Gain baw ............................. L o ~t o p ..............................
February 1937: Fargo. N. Dak.: . - - - - - -
7.4 31.6
14.3 37.6
9.8 32. 1
14.5 37.9
11.4
36.1
14. R
40.5
10.9 37. 6
14. F 39.4
10.4 30.6
12.9 37.9
11.0 30. 5
13. 5 3s. 4
in. fi,
13. 0
31. 8
41.4
12.2 36. 5
13. 5 38.6
11. 7 36.7
13.2 38.3
Gain base ..........................
Loss top ...........................
Galn base .......................... Loss top ..........................
Gain base .......................... Loss top ...........................
Gain base. ......................... L o s ~t o p ...........................
Gain base .......................... Loss top ...........................
Gain base .......................... Loss top ...........................
Gain base. ......................... Loss top. ..........................
Gain base .......................... Lfm top.. .........................
Gain base ..........................
Loss top ..........................
Gain base. .........................
Loss top ...........................
Gain base ........................
Loss top.- .........................
Gain base .........................
Loss top.. ........................
Gain base .........................
Loss top ...........................
Gain hnse .......................... Loss top ...........................
Qain base.. .......................
Loss top. ..........................
Gain bm.9.. ....................... Loss top.-- .......................
Gain base .........................
Loss top. .........................
Gain bRse ......................... IASS top.
August 1937:
Omaha, h'ebr.: February 1937:
August 1937:
Oklahoma City, Okla.: February 1937:
August 1931:
San Antonio. Tex.: February 1931:
August 1937:
Sault Ste. Marie. Mich.: February 1937:
August 1937:
Detroit: Februaw 1937:
August 1937:
Dayton, Ohio: February 1937:
August 1837:
h'ahvnle. Tenn.: February 1937:
August 1937:
Montgomery, Ala.: February 1937:
August 1937:
- ___ .___ -_. ._..__ __. - .- -
TABLE 4.-Differential radiative cooling of lowest strata per degree temperature diference between the layer and the ground-add to free cooling values of table I -
- 100 2
+zoo
10
0-60 m.
Water, cal./cm.*/3 hr. ..................... C 01, cal./cm.~/3 hr ........................
50-200 m.
Water, d./C111.*/3 hr ....................... CO,, cal./cm.a/3 br ........................
Different.id cooling in OC. per 3 hours
(tarn ..._..._.......... .................. 50-2CQ m- ................................
12. 0 9.8
4.3 7.4
.I 3 ,023
15.9 9.2
5.5 6.9
.16 .n25
20.5 8.6
A. 5
6. 4
.I9
.on
27.6 7.9
7.9 6.9
.24 .030
35.9-10-1 7.3.10-2
10.5. 10-2
5.5.10-2
.30 ,036