Analysis of Nimbus satellite high resolution infrared radiation grid point data, surface emissivity in intermediate region, and meteorological modeling for microwave stud

Buettner, K. J. K.

Dana, R. W.

Katsaros, K.

Kreiss, W. T.

Stuetzer, I.

English

NASA Technical Reports Server

ON THE USES OF INTERMEDIATE INFRARED A#D 
MIFOWAVE INFRA- IN METEDROLQGICAL SATEUITES 
Konrad J.K. Euettner 
P ~ b e r t  W. Dam 
Kr?istina Kstsams 
W i l l i a m  T. Krebs 
mgard stuettcr 
March 1966 
Prepared for 
National Aeronautics and Space Administration 
Goddard SFce Flight Center 
Greenbelt, Haryland 
GPO PRICE s 
CFSTI PRICE(S) $ 
ff 653 July 65 
ITHRUI 
,AI66 32136 ' 
UCCESSION NUMBER) 5 -
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WASA CR O R  TUX OR AD NUMBER) 
https://ntrs.nasa.gov/search.jsp?R=19660022844 2020-03-16T21:11:10+00:00Z
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PREFACE -- 
This progress report is the t h i r d  in a series of semi-annw status 
reports on this contract and covers the period f r a n  October 1, 1965 to 
Elhrch 31, 1966. 
of the R 3 . m h s  €!FUR grid point data, theoretical studies of surface 
During this period work has pgressed on the analysis 
\ 
eriss172t7 fs the kt-ediate infrared region and meteaa?c?logical 
~ 2 e L 5 ~ g  5 r the microwave stcd-J. Modifications and calibratiors of the 
micxw3ve x-adiometer as enumerated in  th3 first annual report have been 
nczJ-y ccrpleted. In addition, plans -far further experimental eacissivitp 
. -  
surmmdhg ocean is about 150 cooler. 
tures are about 20 - 2S°K too low, since the t ropical  ocean sbould be 
arour-d 3WK. 
This suggests that t he  t q r a -  
Hot spots a t  12.S0N and 77.5OW as w e l l  as at 14ON, 75.5OW 
are 1 5  t o  20 degrees -r than the sufiounding ocean in a region where 
t he re  are ry) islands. There are also cold spots about 100 colder than 
e i e n t  tarperatures. 
of cloud onue tbe weather data far t h i s  region have been received. 
We hope to  i d e n t i e  these with various types 
The mysterbus cellular system around 7PW, 1WN (7un up and Scar 
front the right side of p.3 in t h e  Nimbus HRIR catalog (1) ) shows a 
uaxm center with up t o  3 W  surrounded by a cool area in the 270's. 
The system just t o  the south of it is both smaller and shows a smaller 
temperature range. 
it could be due e i ther  t o  differemt heights or reflectivities of clouds; 
the weather data should enable us to &au stme defsnite conclusions 
Since t h i s  is i n  the region of specular reflection, 
about th i s .  
Another puzzle is the bright line in the Orinocco region clearly 
vis ible  i n  t h e  picture un p.3 of the catalog (about 6cm from the bottDm 
and 1 / 2 a  from the right edge) -- it is not t o  be found i n  the grid 
point data. 
line, not create it, so it seems l ikely that smoothing of the data has 
The dodging of the catalog pr in t  would only enhance such a 
-2- 
somehow washed out the  t h b  cold line. 
In  the east of the picture at 66OW and around 4 t o  6ON re find 
cold mountah  wi th  temperatuPes around 276O to  2790K while the surround- 
ing te r r i to ry  has tenperetures in the 290's. 
Progrerps is also bebg  made i n  the analysis of the H e d i t e f i a n e a n  
mea grid point data far orbit 207 over tbe area from 350° to  6OW and 
30° t o  SOON; and orbit -1 covering the area f r o m  270° to  29OOW; SSo 
t o  6S0S, a well-defined $outh American f rontal  system. 
A problem complicating the interpretation of these data is the 
presence of APT in tde l rence  of unkaown magnitude. 
however, that it is extpmely unlikely tha t  t h i s  could have caused the 
l i n e  resembling the Orirocco on the p r in t  since numerous physical 
features, coastlines, fivers, mountains, islaads and lakes have been 
identified on the catabg prints. It is very unlikely that tbe  APT 
would create a solstar$ fictitious feature i n  jus t  t he  place where 8 
real feature would apmar. 
It should be noted, 
Two more facts d e  t h e  high albedo of vegetation at 3.5 - 4 microns 
very likely: 
1. Tbe s u h o l d e  basic for organic matter, C - H, has character- 
istic stretching vibrations in tbe  3.0 - 3.7 micron area. 
2. R. Zirkind 42) shows reflectances of orange trees which are 
strongly but irregul+rly increasing fnmr 3.2 t o  3.7 v. 
high as over deserts. 
but the trend a t  that; value indicates still higher albedos for wave- 
lengths greater than 3.7 m i c r o n s .  Exmpolating Xirkind's data up t o  
4 microns yiel& an elbedo of 21% far orange trees. 
They are as 
Measurements, unfortunately, end at  3.7 microw, 
I -3- 
THEOREZICAL MISSIVITY INYESTfGAl'IONS fbl T S  -UTE INFRARED. 
A camput- pmgram is beiag developed, which calculates the equipa- 
l en t  black body temperature observed by a radiometer under apcn sky, wben 
viewing agitated or 
been looked into 80 far the d i h h n c e  f'rm &d &&ace t a p e m t d  
w a s  en t h e  ordm of O.k°K for both d n  aha 
ocean. par t h e  very simple situation thht has 
U&&. his value is 
W g e  enough t o  be significant in certain applications of radiwetxy t o  
oceanography. 
In  short t h e  program has the following components. For the area 
viewed a slope distribution is assigned with itcategories of slope angle 
9,; each categcmy covering a ce r t a in  percentage, PC (t$k), of t h e  projected 
surface area. 
region of interest  is determined far each category of slope from Fresnel 
formulas and Centeno's data on complex index of refraction (3). 
equiwlent black body tanperatme of the  area of t h e  sky reflected by a 
certain slope is calculated by a subprogram. 
The goniometric d s s i v i t y  averaged over t h e  wavelength 
The 
The formula used for rough ocean and the =diameter in zenith is 
as follows: 
N - radiance 
Tx - equivalent black body temperature of the wavy ocean 
IC - dunany index for slope category 
X - number of slope categories 
E (+K) - emissivity of water at angle +K fran zenith 
-. 
! : . " . 
I 
4- 
:itl Wl2 - lowem and upper limit of Plandcian integmtian 
B(TT,IL) - the Planckian for temperature 'IT and wavelength A 
Ts - true acean surface telnpcrature 
X - waveleqgth of electmmagnetic radiation I 
1 T - sky black bady tempmittwe of the sky at the angle 24 from 
z d t b  Seefigure1 
P C ( I $ ~ )  - percentage of the area viewed having slope 9, 
I !  
' 1 -' -radiometer ! 6 I 
The prugram has been tested with a slope distributicnt &rived from a simple 
two dimensional sine wave of 2 units amplitude and 20 uni*s wavelength divided 
into 7 categories of slope. 
with index of refraction data every 0.4 microns. 
The 7.6 - 1 2  micron wavelength region was used 
An analytic formula for the 
equivalent sky temperature T 
derived front radiation measurements with Barnes IT2 radiometer ( 8  -- 12 micrcns\ 
taken on a clear day i n  Seattle sumaer 1965 (4). 
T 
t ion  the  deviation from true surface temperature w a s  approximately 0.4OK €or 
both the flat and rough sea. 
as a function of zenith distance (0) was 
sky 
The formula is 
= A + B sec''*fJ, where A and B are empirical constants. For t h i s  situs- 
sky 
This  theoretical  approach t o  ocean emissivity w i l l  be extended t o  incS;ul? 
a mo= realistic slope distribution. 
pattern Cox and Mtnk (5 )  have developed an analytic formula for the pr&ability 
From measurements of the sun's glit%r 
-5- 
of a certain slop as a function of wind speed. 
incorporated into the present prograar. 
different sky conditions, overcast or par t ia l ly  cloudy, different  regions of 
the electrasragnetic spectrum, the Fadiameter psitimed at an angle fi.aan 
zenith, o i l  slicks present on the ocean surface, etc. will be investigated in 
the  future, 
This fennula can eas i ly  be 
Tbe situation for different seastates, 
A small test program was also written in connection with  our Nimbus I HRIR 
studies. 
if it bad been obtained on the one hand from data of radiance and true tempera- 
ture, and on the other f r o m  solar reflection data. 
have the  sun's energy at  the earth's distance! corresponding approxhately to  
that  of a 3500K black body. 
maximum t o  the sbort wavelength end of the window, a 350°K body w o u l d  have the 
maximum t o  the lung wavelength end. 
curve E{A), with E(A) = 96% a t  3.3 microns and 60% at 4.2 microns, decreasing 
#e w e r e  curious about how much the calcuZated emissivity would differ,  
For t he  4 micron window we 
Hawever, while the  sun's energy curve has its 
Me assume a very steep spectral  emissivity 
monotonically between, with data every 0.05 m i c r o n s .  
+(A)  is ,@st 5.n t h e  ca&fog Cd). 
on t h e  Planckian energy cumre of a 35WK body, and also an the Planckian energy 
curve for 6000OK reduced by a fractional value, Fr = 2 . 0 h  6000 t o  account 
for the dbtance of the earth *the sua. 
ly/mh, and we assume no loss due to  the atmosphere for the window, 0 6 0 0 0 ~  is 
t h e  total energy output of a 600O0K black body, and u is Stefan Boltenann 
constant in uni ts  of ly/Din°K . 
above an average emissivity can be calculated for each case, designs?ed E n 3 .  
EZ respectively. 
The Nimbus filter curve 
These twe spectral curves are suprbposed 
4 
2.0 is t he  solar constant in 
4 The sun is assumed a t  the zenith. horn the 
Y - 
, - .  . 
I : . * .  
-6- 
The formulas for the Calculations are the following: 
4.2 
E = 3.3 ' 4.2 
3.3 
-- I S(A) + ( A )  B(drj0,X)dA 
b 
I O(A) B(dS0,A)dA 
The result  far, this extremely steep spectral. emissivity curve w a s :  E 
andEz = 76.7%. 
There is a certain tempmature dependence for E such that at f = 24WK 
E = 72.1%, whilt at T = 31WKE =73.2%. 
= 7 3 . a  
Y 
Y - 
Y P 
-1- 
The average infrared emissivities of temstttidl aterids as d~qufcad by 
~ y a n  and m s  ($1 f~dh metdci. data s m  A nbtabie dbffewees M 
those values measured by Buettner and Kern ( 7 )  with the emissivity box. A 
t h i rd  method of 
posal here is t o  cmpare directly the infrare d signal froat the substance of 
is needed to clear up the discrepancy. "be pm- 
in te res t  with that of a known black body at the same temperature. The B a r i t e s  
IT-2 Infrared l'hemmaieger is t o  be pointed alternately at the  sample and the 
aperture of a black body-cavity. The result ing outputs give thg average 
emissivity of the strrface over t he  8 - 1211 region by the ratio 
12 
f ¶(A) B&<T,A) dA 
8 
where q(&) is the filter functkm of t he  instrument and BA(T,A) is t he  black 
body spectral radiance. 
The blackbady radiation will be produced by a cavity of 2 slender, hollow 
cones soldered base-against-base with an aperture a t  one apex and w i t h  a 
uniform temperature controlled by a f l o w  of water over the outside. 
in te r ior  is painted with Parso~l'S Elack an dssivity jpeater than. 0.895 can 
If the 
easily be obtained. 
Since the  sample is not black,- must worry about the sample signal being 
too large due t o  reflected radiation fram its sumoundings. 
the sarnple is placed in  a container kept at &y ice temperature, 1 9 5 O K .  
additional term due t o  19S0K emission i n  the expression f o r  
To avoid this, 
The 
should be a3xC 
2% of the -le radiance, down t o t h e  noise level  of the instrument, and CZI 
be measured along wi th  the lesser effects  of multiple reflections from saqie 
. '  
-8 
and sh ie ld  by replacing the dangle by a cold metal mirror. 
Inherent in the design of the a p ~ t u s  w i l l  be the capacity t o  measure 
the  angular variation in the infrared emissidn. 
fully studied that w i U  be investigated are ttariow k d  of sand$ and dune 
structure and the IR emission of w e t  versus dry s k i  
Othef. properties not yet 
1 
I '  
-9- 
The Uic+raye Stdy 
* . .  . *- , : 
Emphasis during t h e  past six kths M s  been given t o  the theoretical 
aspects of atmospheric probing using a paskive microwave system. Consideration 
has been given t o  the methods far data collection and t o  interpretation of 
the data. caapttter programs for the absorption coefficient and brightness 
tempem- over the frequency range of 1-40 gc/s have been written and a 
number of simple models have been constructed t o  aid in t he  interpretation of 
observaticme. An observational program has not yet begun primarily due t o  
delays in obtain- antenna range time, but is scheduledto begin shortly. 
Methods of Data Collection 
In previous reports it w a s  stated that the 19  gc/s radiometer had been 
constructed wi th  two operational configurations i n  mind. 
ra ther  large pamabola for sky, rainfieu and terrain emissivity observations 
The first using a 
and the other using a small horn antenna for emissivity measurements on small 
samples. 
l i gh t  aircraft has also been mentioned. 
The possibil i ty of using a compact version of t h i s  radiometer on a 
Thoughtful consideration as t o  which 
methods would provide the most relevant and significant data has led to the 
abandonment of t h e  measurement of the  d s s i v i t y  of small smples and to 
increased emphasis on aircraft flights. The observational program w i l l  begin 
w i t h  ground based measuccmenfs but a cooperative program w i t h  t he  Baing 
Company w h e r e b y  high a l t i tude  flight t h e  on a 707-32OC could be obtained on 
an unscheduled basis is being pursued. 
this cooperation lies i n  the e x p e n d i m  requbed to  design and install a 
special antenna t o  meet requind safety and aerodynamic specifications on t t i s  
The nain di f f icu l ty  in establishing 
aircraft. 
For the purpose of modeling the meteorological si tuation corresponding to  
a set of otmervations a gtrneral p k e m  capable oi qmea&Ting Sc~eral basic 
models 5s being m'itten. 
absorption aioag a specified atmospheric path and the brightness temperatwe 
looking alarrg the same patb. Gaseous absorptitm is as@ to be adequately 
described by the  Van Vleck equations fcrr oxygen and wat# v a p .  
late matter measured values of one-way attenuation are used t o  describe the 
extinction of atmospheric radiaticm. 
being, but w i l l  be introduced as t h e  modeling develops. 
cal cases Wi&l be calculated for t h e  purpose of p=dicthg 
tempesature and changes of brightness temperature under real eanditions. 
This program UksQped to ca;lc&te the total 
For particu- 
Scattering is being ignored for t h e  tirnc 
A utrdlber of theoreti- 
brightness 
Radiometer Testing and Modification 
During the past six months the microwave radiometer which MS described 
i n  t h e  first annual report on t h i s  contract has been repackaged t o  rcduce its 
s i ze  and weight. The antenna radiation pattern has been obtained on the 2000 
foot pattern range of the  Boeing coplpany and was found t o  have t h e  following 
characteristics for vertical polarization: 
Beamwidth between half-power points--- 
Azimuth = 2 d W  Elevation = 2;5W 
Beamwidth between one-tenth-power points--- 
Azimuth = 3.920 Elevation = Q36P 
Maximum side lobe! level = 21.0 db 
Approximate antenna gain = 36.0 db 
This performance is less than calculated and is probably due t o  misal&m=t 
of t h e  feed horn. It is hoped than an adjustment can be made and a new 
-11- 
pattern obtained dt d Ute+ &tcA 
The IF post-amplifier bandwidth has been increased from 3 mc/s to 8 mc/s 
by substituting an LEL amplifier for the AIL amplifier of the original mcdel 
and the radiometer is now undergoing some bench and field testing t o  determine 
its present characteristics. 
along with sky brightness temperature measuItements. 
1 O O O K  per inch has been achieved and will be increased substantially when the 
range of the balance voltage circuit is extended. 
Several solar drift  e w e s  have been obtained 
Recorder sensitivity of 
. . ~  - . 
I : - .  
-12- 
- References 
1. Nimbus I, High Resolution Radiation Data Catalog and Users Manual, Vol. I ,  
Photofacsimile Film Strips,  Goddard Space Flight Center, Jan. 1965 
Z i r k h d ,  rZ. , c)lr Infmred Spkhal  R e b t a n c e  of Terrains from Airborne 
Platforms, Phetaqt,*ac@ ,&edce, V b L  13, pp. 1004-LOdS, 1965 
Centeno, V.M., ‘The Refractive Index of Liquid Water i n  the N e a r  Infrared 
2. 
3.  
Spectrum;. -- J. Opt. SOC. Mer., --. Vol. 31, 1941, pp. 244-247. 
4. 
5 .  Cmt ,  Ch. and W. Munk, Stat is t ics  of the Sea Surface Derived frars Sun Glit- 
F i r s t  Annual Report on Contract NASA NsG- 632 
ter, J. Har. Res., Vol. 13, 1954 
Lyon, R.J.P., and Burns, E.A.. 
Working Group on Extraterrestrial Resources at Cape Kennedy, Fla., Nov. 17,  
1964 (Submitted to JourndL of Geophysical Research). 
Buettner, K.J.K., and Kern, C.D., JGR, -- Vol. 70, pp 1329-1337, March 15, 1965 
6. Puper presented at  Third Annual Heeting 05 
7 .  
ON THE USES OF I??TEIwEbfATE: IW%ARED AWD 
Konrad J.K. Buettner 
Knistina Katsaros 
W i l l i a m  T. Kreiss 
Irmgard Stuetzer 
PQbtX't w. PSna 
March 1%6 
Prepared for 
. . I  * . I. - .  r .. 
National Aeronautics and Space Administration 
Goddar? SFce Flisht Center  
Greenbelt, Maryland 
-. 
? : 
- - *  . '- 
HTUR GRID DATA ANALYSSS 
The K m b u ~  HRIR grid point &?a far orbit 195/96 foe. the d a y t h  
ful ly  aaaiyzed. A 3  an OItampla of lad-water contrastsII the clearly- 
defiried island 05 Jamaica is at a tempemture of 290 - 23S*K, %8zlle the 
surrocnding ocean is about 15O cooler, This suggests thar the tespem- 
tures are about 20 - 2S°K too l o w ,  since the tropical ocem sbould be 
arourid 3000K. kt spots at 12.5ON and 77.5OW as well as at 14*N, 75.5OW 
are 1 5  to 20 degrees wanner than the surrounding ocean in a region where 
them are IIO islands. 
amkient teaperatures. 
of cloud owe the weather data for t h i s  region have been mcdved. 
There are also cold spots about 100 colder than 
We hope to i d e n t i e  these with various types 
The mysterious cellular system around 78OU, l b o N  (7cm up and SCB 
frm the right side of p.3 in tbe Nimbus HRIR catalog (1) ) shows a 
w a r m  center with up to 3000 surrounded by a cool area in the 270'8- 
The system just to the south of it is both smaller and shows a smaller 
temperature range. Since t h i s  is in the region of specular reflection, 
it could be due either to different heights or ref lect iv i t ies  of clouds; 
the weather data should enable us to draw some definite cocclusions 
about this .  
Another puzzle is the brigbt l ine  in the Orinocco region clearly 
vis ible  i n  the picture on p.3 of the catalog (about 6cm from the bottam 
and f/2cm f r o m  the right edge) -- it is not to be found in the gr id  
point data. 
line, not create it, so it seems likely that smoothing of the data has 
The dodging of the  catalog print w w l d  only enbance sucb a 


On the uses of intermediate infrared and microwave infrared in meteorological satellites Third semiannual report

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