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Following the SOAS project, we tested each sonic in a zero-wind enclosure within the EOL temperature chamber, measuring wind component offsets and sonic temperature errors over the nominal range -30 C to 55 C.  The procedure is to warm the chamber up to 55 C and then slowly decrease the temperature linearly to -30 C, followed by slowly increasing the temperature back to 55 C.  The zero-wind enclosure holds two sonic heads on their sides (with the v-axis vertical) and electronics, one above the other and separated with a horizontal layer of rigid blue foam.  On the cool-down cycle, the atmosphere around the top sonic is unstably stratified (cold enclosure lid above warmer air) and that around the bottom sonic is stably stratified (cold enclosure bottom below warmer air).  The opposite is true during the warm-up cycle.  Both the wind component data and the sonic temperature data have significantly less variance when the air is stably stratified, and thus we use data from the bottom sonic during the cool-down cycle and data from the upper sonic during the warm-up cycle.

The following table shows wind component offsets as okay if the u and v offsets are less than +/- 4 cm/s and the w offsets less than +/- 2 cm/s.  If the zero wind offset exceeds these thresholds, the table lists the temperature range of the over-limit offset and the largest amplitude of the offset.  The plots of offsets versus temperature can then be examined to determine the exact nature of the offset.

The last column relates to the following project, METCRAX, in October 2013.  The operating temperature range for night-time warm-air intrusions into the crater is on the order of -10 to +20 C.  The last column notes whether or not the sonic is suitable for that temperature range. 

SN

Location

EOL Cal

CSI Cal

u

v

w

METCRAX?

0536

FLR 3m

8/1/13

6/27/12

ok

ok

ok

OK

0537

NEAR 3m

8/1/13

6/21/12

ok

ok

ok

OK

0538

NEAR 10m

7/25/13

10/17/12

32 - 49 C
-7 cm/s
@43 C

46 - 49 C
-7.3 C
@ 49 C

44-46 V
-2.5 cm/s
@ 45 C

OK

0539

FAR 3m

8/2/13

6/20/12

ok

ok

ok

OK 

0540

Rim 15m

 

2013 recal

 

 

 

OK

0671

Rim 25m

8/3/13

6/28/12

ok

ok

ok

OK 

0672

NEAR 30m

7/26/13

10/10/12

35 - 49 C
+8 cm/s
@ 47 C

36 - 49 C
-7.4 cm/s
@ 49 C

ok

OK

0673

RIM 35m

7/25/13

7/18/12

ok

25 - 44 C
+6 cm/s
@ 39 C

20 - 50 C
-3 cm/s
@ 34 C

OK

0674

NEAR 40m

7/29/13

8/13/12

ok

ok

ok

OK

0677

spare

8/2/13

6/17/12

ok

16 - 30 C
-7 cm/s 
@ 23 C

ok

Requires
CSI recall

0720

NEAR 45m

7/31/13

12/31/11

ok

ok

ok

OK

0738

not used

8/1/13

5/12/10

17 - 25 C
-4.8 cm/s
@ 21 C

10 - 45 C
-8 cm/s
@ 20 C

26 - 42 C
+2.4 cm/s
@32 C

Returned to
RAL

0739

RIM 5m

8/1/13

8/18/10

46 - 55 C
> +8 cm/s

ok

48 - 55 C
+2.8 cm/s
@ 55 C

OK

0740

NEAR 50m

7/31/13

8/28/12

ok

ok

26 - 36 C
-2.4 cm/s
@ 31 C

OK

0800

RIM 40m

7/29/13

6/19/12

ok

10 - 35 C
+8 cm/s
@ 21 C

17 - 53 C
-3.6 cm/s
@ 45 C

Requires
CSI recal

0853

NEAR 35m

8/2/13

6/21/12

ok

ok

ok

OK 

0855

spare

8/3/13

9/12/12

-13 - 1 C
-4.4 cm/s
@ -11 C

ok

44 - 49 C
-2.8 cm/s
@ 47 C

Marginally
OK

0856

NEAR 20m

 

2013 recal

 

 

 

OK

1117

NEAR 25m

 

2013 recal

 

 

 

OK

1119

spare

7/26/13

8/9/12

ok

49-53 C
+7 cm/s
@ 53 C

1 - 44 C
-3 cm/s
@ 17 C

Marginally
OK

1120

RIM 20m

 

2013 recall

 

 

 

OK

1121

spare

7/26/13

12/8/11

-14 - 24 C
-11 cm/s
@ -9 C

-14 - 44C
-9.5 cm/s
@ -7 C

-15 - 49 C
-5.6 cm/s
@ -9 C

Requires
CSI recal

1122

NEAR 15m

7/26/13

12/8/11

28 - 53 C
+5.8 cm/s
@ 36 C

49 - 53 C
-4.3 cm/s
@ 53 C

48-53 C
-2.7 cm/s
@ 53 C

OK

1123 

RIM 30m

 

2013 recal

 

 

 

OK

1124

RIM 10m

8/2/13

7/19/12

ok

ok

ok

OK

1244


7/30/13

 

-25 -  49 C
+17 cm/s
@ 27 C

11 - 30 C
+5.5 cm/s
@ 23 C

18 - 42 C
+6 cm/s
@ 28 C

Requires
CSI recal

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