-'. 

1'1 '1-.1+9 

NASA-CR E iC 

IJ d 

-,j1~oa to C&2.3 - -----------

A Reproduced Copy 

OF 

Reproduced for NASA 

by the 

------

NASA Scientific and Technical Information Facility 

111111111111111111111111111111111111111111111 

NF01463 llBRARV n r: ~y 

JUN 5 Ht:J 

LANGLEY ,.ESl, • :i1 

Lle~A"Y. ' 

FFNo 672 Aug 65 
· . ' 

Final Technical Report NASA Grant NAGW-228 

Principal Investigator, C. B. Leovy, University of Washington 

Analysis of the Viking Lander 1 Surface Wind Vector for Sols 45 t~· 376 

Summary of Project Approaches and Results 

The purpose of this project was to find a means for correcting Viking 

Lander 1 wind sensor data during the period between sols 45 and 375. During 

this period, the heating element of the quadrant sensor which provided the 

primary signal used for determining wind direction had failed, but both hot 

film wind speed sensors were functioning normally. As a consequence the 

SANKET Program, used to provide wind speed and direction information, was not 

providing reliable results and an alternative procedure had to be developed. 

The procedure which was tried and eventually adopted was as follows. 

(I) The following information from the sensors was bin-averaged in 25 equalsized bins per sol: Nusseldt numbers corrected for radiation effects determined separately for hot film wind speed sensors 1 and 2 (NUl, NU2), 

approximate wind speed determined only from these Nusseld~ numbers (VQD, the 

error in the approximate determination relative to wind tunnel values is ~5% 

and was neglected), quadrant sensor thermocouple voltage differences,(QI, Q2, 

defined such that QI)O if thermocouple #1 had a higher temperature chan thermocouple 02 and Q2)O if thermocouple 03 hai a higher temperature than thermocouple #3. See Fig. 1 for geometry of the wind sensor assembly. In 

addition, the number of data points per bin (typically ~IOO) was recorded. 

(2) The function 

NU2-NU1 

F( 9,VQD} - (NU2-NU1)lf2 

was evaluated for each bin. This function depends on wind direction with up 

.. 

to a 4-fold ambiguity. It also depends on wind speeds for winds below ~ mIs, • 

but only weakly. Calibration curves of F vs. wind direction e, determined 

from SANMET for VL-1 sols prior to sol 45 and for selected VL-2 sols are shown 

in Fig. 2. 

{3} Wind directions were divided into 12 sectors according to the values of 

F, QI and Q2 according to Table 1. Only the signs of F, AI, Q2, and 

R • /QIII/Q2) - I were used for this purpose. The sign groupings in Table I 

follow from the geometry {Fig. I} for positive quadrant sansor post overheat. 

During the period of quadrant sensor heater failure, signals were observed on 

the quadrant sensor ~hermocouples at certain times of the day ariSing from 

radiative overheat or the quadrant sensor post relative to ambient air. 

Typically, clear cut signals occurred between 0800 and 1600 local time. 

During most of the remainder of most sols, the voltages were flat and slightly 

negative. These negative values were interpreted as blas voltages and had the 

values -.09mv (Q2) and -oSmv (Ql). Before assessing the signs of Ql and Q2 to 

be used in conjunction wlth Table 1, these biases were subtracted. If the 

resulting magnitude of QI or Q2 did not exceed .05 mV (our estimate of the 

random voltage noise, about 1 dn), it was taken to be a null value. 

(hASA-CR-174J~9) ANALYSIS CF ~hE VIKI~G 

LAhilEE 1 SUBIACf W1HD ViC1CB FGS SOL~ 45 70 

315 Final 7ecun~Cd~ Seport C~dshinqtoD 

Univ.l 13 p He. AC2/HF A01 CSCL OJa 

G3/91 

N8S-18932. 

Unclas 

01119 

-rl- ',' tr' , 
z 

(4) /bring the portion of each 001 when there was a null signal on Ql or Q2. 

only the ~uadrant shown in Table 1 could be estimated a priori. This was done 

by using the continuity of the F signal in time: no change is sign of F 

implies no change in quadrant. a change in sign implies a change in quadrant. 

When a quadrant change occurred. judgment had to be exercised in order to 

determine whether the rotation was clockwise or counterclockwise. Moreover. 

within each quadrant 
3 

resulting wind hodographs are shown in Figs. 6 and 7. We are currently 

extending the effort in two directIons under another grant: (a) completing 

the reduction of wind data between sols 45 and 240 and. (b) using winds 

determined in this way to ·calibrate" the quadrant sensor signals (durIng the 

daytime), so that these signals can be used by themselves to determine wind 

direction after the failure of one of the hot film wind sensors on sol 375. 

Reference 

Leovy. C. B., J. H. TIllman, W. R. Guest. and J. R. Barnes, 1984: Interannual 

variability of Martian Weather. Proceeding of Seymour Hess Symposium. 

IAMAP, Cambridge University Press (in press). 

. . . . . 
guadrant Sector Angle Range F gl g2 R Remarks 

I la 012-035 F)O QI(O Q2)0 R(O 

I Ib 035-057 F)O Ql<O Q2)0 R>O counterclockwise sector half, R small 

I Ib 057-080 F>O QI(O Q2>0 R>O clockwise sector half, R large 

I Ic 080-102 F>O QI<O Q2<0 R>O 

2 2a 102-125 F(O QI(O Q2(0 R<O 

2 2b 125-147 F<O Ql(O Q2<0 R<O counterclockwise sector half , R small 

2 2b 147-170 F(O QI<O Q2(0 R(O clockwise sector half , R large 

2 2c 170-192 F<O Ql>O Q2<0 R<O 

3 3a 192-215 F>O Ql>O Q2(0 R<O 

3 3b 215-237 F>O Ql>O Q2<0 R>O counterclockwise sector half, R small 

3 3b 237-260 F>O Ql>O Q2<0 R>O clockwise sector half , R large 

3 3c 260-292 F>O Ql>O Q2>0 R>O 

4 4a 292-305 F(O Ql>O Q2)0 R>O 

4 4b 305-327 F(D QI<O Q2>0 R<O counterclockwise sector half, R small 

4 4b 327-350 F«(, QI<O Q2>0 R<O clockwise sector half , R large 

4 4c 350-012 F<O QI<O Q2>0 R(O 

Table I. Sector nomenclature and relationships between wind-sensor assembly signals, sectors, and 

lingles. 
5 

Bin Time of Day Difference Time of day Difference 

(fraction of sol) (deg) (fraction of sol) (deg) 

1 20.02 - 2.7 21.02 - 9.5 

2 20.06 - 2.6 21.06 - 4.9 

3 20.10 - 4.6 21.10 - 0.1 

4 20.14 - 4.3 21.14 - 3.6 

5 20.18 + 6.1 21.18 - 4.8 

6 20.22 - 5.9 21.22 - 4.9 

7 20.26 - 0.2 21.26 - 9.3 

8 20.30 +18.2 21.30 + 0.8 

9 20.34 +12.9 21.34 - 8.0 

10 20.38 -15.4 21.38 -12.1 

11 20.42 - 7.9 21.42 + 1.5 

12 20.46 - 3.5 21.46 

13 20.50 +11.4 21.50 +11.0 

14 20.54 + 2.6 21.54 +14.9 

15 20.58 +22.0 21.58 +15.9 

16 20.62 +12.4 21.62 + 9.3 

17 20.66 - 7.4 21.66 - 8.6 

18 20.70 +22.9 21.70 - 4.8 

19 20.74 + 7.4 21.74 - 6.7 

20 20.78 + 4.5 21.78 - 4.9 

21 20.82 + 5.1 21.82 -13.3 

22 20.86 -27.2 21.86 -40 .• 6 

23 20.90 7" .7.8 21.90 + 2.3 

24 20.94 + 5.6 21.94 + 4.1 

25 20.98 -18.8 21.98 - 5.9 

Table 2: Differences (in degre"es) between bin average directions calculated 

from the wind sensor only and those calculated by SANMET. 

· . i . 

.- "." 
6 

Figure Legends 

Fig. 1 Geometry of Lander 1 wind sensors relative to directional coordinates 

on Mars. Notation: TC - wind direction sensor thermocouple, ws - hot 

film wind sensor. 

Fig. 2 Calibration curves for F derived from a combination of data from VL-I 

prior to sol 45 and VL-2 data. 

Fig. 3. Example of bin average data for QI, Q2 and F for VL-l sol 246. 

Fig. 4 Technique test results, VL-l sol 20. Wind sensor only wind direction 

(ANSWS, derived as described in the text) are compared with wind 

directions determined by SANMET. Error bars represent the standard 

deviation of the difference between ANGWS and SANMETwinds. 

Fig. 5 Same as Fig. 4, except for VL-l sol 21. 

Fig. 6 Example hodographs for VL-I derived by the wind sensor only technique 

(ANGWS). Sol number (upper right) and LS value (upper left, parentheses) are given. 

Fig. 7 Same as Fig. 6, but for VL-I sol 320. 

VQD ............. a-'4 ~/s ~~:!is ••••••••••••• 7 8 ~/s 

0.50 )~ l 

I \, 1 

0.40 

0.30 

0.20 

o . 10 

(j) -0.00 z 

0 

H 

- 0 . 1 IU 

z 

::) -0.20 

Wi- -0.30 

-' 

w 

l/1 -0.40 ::::> 

z 

-0.50 

.... \ \; ... J 1 .... ~"" . .' " \ 

! \ I .:' . 1\\ i I 

i / i'-- \, In/ \ \\ I I I I LLJ \ if 

: \: ,. 

.~ /1 ~ "; ~ \1 1 j 

/ / , ......... ". r\\ J :/ "\ \ f'\" LI 

II : .' ,\ It! \ " o. \ 

I '. ... " .\ U 

/ :.1 ...-- 1\\ I~ I \\ \1 

--- r-...... ... f I I I , , 

. I/-' [I I": .. \ \ V If: ~. \' ~ 

i i 

"I ~ 

. :j \ 

\.\ V )1 ··S ~ I 

.I f~ .. ~ ~ V VI \--- , l ~ I 

0 ~ .. ........ :j / .. 1/' 1 --- ..... 

'/ \ tl/ .. \ .... .' \ ~~'" . \ 

\\ :--.... ....... / . / \\ ~ '-'J -~ - . 

\. .. / ~ 11/ i 

'. .. r\: I \ . 7~o' " -/ '1 I . '. 00' 

I 

H-\~'\~~Il " ,- -".1"'- r-~ " : I 

<~+:'1 r- +1- 11-"1 

o 90 180 270 

. 

, ' ·.WINe> DI~E'CTIOtJ 
" .4-" 

0.20 

- 0 . 0 0 

-0.20 

-0.4-0 

1. 6 0 

0.80 

- 0.00 

-0.80 

- 1. 6 0 

- l. 00 

0.80 

0.60 

0.4-0 

0.20 

- 0.00 

- 0.20' 

-0.4-'0' 

- 0.60 

-0.80 

AVER DATAl 

E 

... 

?Uh ~ri1 

• 

25 DATA POINTSI VOD: 0. ~ -8 0 . ~i'ilS SOL: 24-6. If) ~ -

o a o o 

o 0 000 

• • ~ II I!l Q 'i1 

t .. .. 

.. .. .. 

• 

.. + .. t 

.. .. + 

?LJ.h ?C) - ',ME" . 246. S0 • (SOL=It)- 246. 7S 

Q.~ a 

QI + 

Q2.-Gll 

,/ (Q.l-Ql) a... 

.. .. 

.. 

247.00 
· .. __ ._-.---_ ..... - ... _-----------..... 

3 

'---- -- \1 5ANMf:T 

., 

WIND Sem~a. ONLYS 

/ 

Ii'" 

I 1 ; ; " ... 1 __ J, , .. I 

~~' ... 

. I 

o 

(: 
a 

:z 

3 

3 

20 

So L :2. I 

IIQD~ / :,..~ 

, .. . . A,-'-- .' ! ... --~A~ ---- --:-.,,-... ---- . I ______ --;L . __ o 5" 

." 

r 

1.A~~ r' L I 

,r 

., I' 

., 

;/ 

;' , 

! I 

,..... 

., 

10 

-~ 
151 5 

I 21 (106) 280 (253) 

I 

101 

i 0 241 ! I ·3 

I 

1 . ~ I 

I 

Sr- I -5 

I IS 

(/) I ...... 

~ 9 

- 0 -10 

> 

-

~ 

Z 

w 

Z -5 -IS 0 

a. -10 -5 0 5 10 -IS -10 -5 0 5 

~ 

0 5 5 

u 256 (237) .J 

<t 

Z 

0 

5 0 0 

~ w 

~ 

-5 . -SI 

-1011-----.:...-------j~--_l -101-----\-----+-7"""----

-IS1---.....I..--_-L-__ ---I ___ ..J -IS'------'----~--------~-' 

-IS -10 -S 0 S -10 -S o 5 10 

ZONAL COMPONENT (U), MIS 

LANDER 1 HODOGRAPHS 
O.O~------~------~------'-------I 

-

'-

~ -5.0 ~----~4--------+------~~-----~ ~ 

-

IZ 

W 

Z 

o 

~. -10. 0 ~+----t-----~::---F.=====-1r7-==--~ 

o 

u 

o 

a:: 

c::x: 

3: 

:r: -15. 0 1----~+---__=7t n------t---------; 

fa:: 

o 

z 

-20.<2. 13.0 -8.0 -3.0 2.07.0 

EASTWARD COMPONENT (MIS) 

End of Document