ASTEX C-13lA FLIGHTS
         CLOUD MICROPHYSICS PROBE (PVM-lOOA)
         DATA: ~10 HZ, 1 HZ; ASCII; DOS COMPATIBLE
               1) LWC (LIQUID WATER CONTENT; G/M^3)
               2) PSA (PARTICLE SURFACE AREA; CM^2/M^3)
               3) R(EFF) (EFFECTIVE DROPLET RADIUS, UM)


         (H. GERBER; 1643 BENTANA WAY, RESTON, VA 22090)
             (PHONE 703-742-9844; FAX 703-742-3374)




FLIGHT INTERVAL	   U. OF WASH.	  10 HZ	  1 HZ
 NO.	NO.	  TIME INTERVAL	  DATA	  DATA
		(hhmmss - hhmmss)  FILE	  FILE


1557	 1	 092900 - 100300	ASTEX01.10	ASTEX01.lHZ
2 June   2	 101000 - 105656.1	ASTEX02.10	ASTEX02.lHZ
	 3	 112600 - 122000	ASTEX03.10	ASTEX03.lHZ

1558	 4	 110500 - 115700	ASTEX04.10	ASTEX04.lHZ
4 June   5	 123100 - 133300	ASTEX05.10	ASTEX05.1HZ
	 6	 140800 - 145200	ASTEX06.10	ASTEX06.lHZ

1559	 7	 104333 - 104800	ASTEX07.10	ASTEX07.lHZ
8 June   8	 115000 - 125600	ASTEX08.10	ASTEX08.1HZ

1560		NO CLOUDS
10 June

1561 	 9	 093600 - 101100	ASTEX09.10	ASTEX09.lHZ
12 June  10	 102200 - 111200	ASTEX10.10	ASTEX10.lHZ
	 11	 113500 - 121800	ASTEX11.10	ASTEXll.lHZ
	 12	 131300 - 134500	ASTEX12.10	ASTEX12.lHZ
	 13	 142100 - 144000	ASTEX13.10	ASTEX13.lHZ

1562	 15	 100900 - 101600	ASTEX15.10	ASTEX15.lHZ
13 June	 16	 110000 - 111000	ASTEX16.10	ASTEX16.lHZ
	 17	 114300 - 114900	ASTEX17.10	ASTEX17.lHZ
	 18	 125700 - 135800	ASTEX18.10	ASTEX18.lHZ
	 19	 140100 - 144900	ASTEX19.10	ASTEXl9.lHZ

1563 	 20	 151200 - 160500	ASTEX20.10	ASTEX20.lHZ
15 June  21	 161100 - 165000	ASTEX21.10	ASTEX21.1HZ

1564	 22	 115500 - 122500	ASTEX22.10	ASTEX22.lHZ
16 June  23	 150500 - 154000	ASTEX23.10	ASTEX23.lHZ

1565	 24	 091000 - 091500	ASTEX24.10	ASTEX24.lHZ
17 June	 25	 093700 - 103700	ASTEX25.10	ASTEX25.1HZ
 	 26	 103700 - 113200	ASTEX26.10      ASTEX26.lHZ
 	 27 (1)	 114500 - 123600	ASTEX27.10	ASTEX27.lHZ
					ASTEX27.1
  	 28	 125800 - 130100	ASTEX28.10
					ASTEX28.lHZ

1566		NO CLOUDS
19 June

1567	 29	 161500 - 161800	ASTEX29.10	ASTEX29.lHZ
20 June  31	 200200 - 201200	ASTEX31.10	ASTEX31.1HZ

1568	 32	 090100 - 090600	ASTEX32.10	ASTEX32.lHZ
21 June	 33	 093800 - 103800	ASTEX33.10	ASTEX33.1HZ
	 34	 103800 - 110000	ASTEX34.10	ASTEX34.lHZ
	 35	 111600 - 112900	ASTEX35.10	ASTEX35.lHZ

1569	 36	 050800 - 051100	ASTEX36.10	ASTEX36.lHZ
22 June  37	 053100 - 053300	ASTEX37.10	ASTEX37.lHZ
	 38	 055300 - 061100	ASTEX38.10	ASTEX38.lHZ
	 39	 070800 - 071100	ASTEX39.10	ASTEX39.lHZ
	 40	 072600 - 073000	ASTEX40.10	ASTEX40.lHZ
	 41	 081000 - 090600	ASTEX41.10	ASTEX41.lHZ

1570	 42	 131500 - 135000	ASTEX42.10	ASTEX42.lHZ
23 June

1571	 43	 094200 - 104000	ASTEX43.10	ASTEX43.lHZ
26 June	 44	 104000 - 114000	ASTEX44.10	ASTEX44.lHZ
	 45	 114000 - 124000	ASTEX45.10	ASTEX45.lHZ
	 46	 124100 - 134200	ASTEX46.10	ASTEX46.lHZ
	47	 140000 - 150200	ASTEX47.10	ASTEX47.lHZ

1572		NO CLOUDS
27 June

NOTES:

(1) PSA channel inoperative during this interval. R(EFF) estimated by 
correcting FSSP data; see ASTEX27.1.
(2) Due to digital round-off errors in the raw data, the data rate in 
the 10 HZ DATA FILES is 9.84572 Hz, except for files 32,36,37,38,39,40,41 
where the data rate is 10.03773 Hz, and except for file 33 where 
the rate is 10.00000 Hz.  All the ~10 Hz data has been synchronized 
with the U. of Washington 1.00000 Hz data files.


DATA REDUCTION

1. INTRODUCTION - The raw data of LWC and PSA collected with the PVM-lOOA 
on the C-131A flights resides in the U. of Washington ASTEX data base. The 
following summarizes the reduction of this raw data.

2. SCALING CONSTANTS - The following equations relate 
LWC and PSA to output voltages and scaling constants of the PVM-lOOA:

LWC (G/M^3) = LWC (VOLTAGE) x 2.515
                 PSA (CM^2/M^3) = PSA (VOLTAGE) x 7,700

The raw data set consists of LWC and PSA voltages. The reduced data set 
consist of values to which the scaling constants have been applied. The 
scaling constants were determined in a calibration as described in 
"New Microphysics Sensor for Aircraft Use" by H. Gerber; Preprint 
Volume, 11th Intern. Conf. On Clouds and Precipitation, Montreal, 
Aug. 17-21, 1992.

3. VOLTAGE OFFSETS - The raw voltage data for the LWC and PSA channels 
contained voltage offsets which were typically -.050 V for each channel. 
The reduced data has most of the offset removed.

4. CALCULATION OF R(EFF) - The equation for R(EFF) is given by

R(EFF) = 30,000 x (LWC/PSA)

Since R(EFF) is proportional to the ratio of LWC/PSA, large errors in 
R(EFF) will result when LWC and PSA approach zero value. Conditional 
statements are applied to the LWC and PSA data, which return the 
relationship R(EFF) = 0 when the values of LWC and PSA are smaller 
than a specified value:

IF LWC < .020 G/M^3 THEN R(EFF) = 0
                 IF PSA < 60 CMA2/M^3 THEN R(EFF) = 0

The reduced R(EFF) data contains the effect of these conditional statements.
The reduced R(EFF) data shows single data-point spikes that can occur when 
there are large changes in the density of the cloud, such as at cloud edge. 
These spikes are a result of a 26ms displacement of the A to D conversion 
between LWC and PSA channels; this displacement corresponds to about a 
2-m distance along the C-131A flight path given the ~80 m/s speed 
of the aircraft. Spikes in R(EFF) occur when the PSA measurement occurs out 
of cloud and the LWC measurement occurs incloud; and spurious 0 values of 
R(EFF) occur when the measurement sequence of LWC and PSA is reversed with 
repect to the cloud edge. Spikes and spurious 0 values have not been 
removed from the reduced data set.


5. ACCURACY - The accuracy of the LWC channel is ~5%, and the precision of 
the LWC and PSA channels is ~2%, for the dropletsize bandpass of the 
instrument's design. The accuracy of the PSA channel is estimated to be 
similar to the accuracy of the LWC channel, because of calibration, and of 
the physical consistency of the data produced by both channels in this 
ASTEX data base. However, some doubt must remain as to the accuracy of PSA, 
since the calibration of this channel depended in part on the performance 
of a FSSP used during the instrument's calibration in the cloud chamber at 
ECN, Petten. The instrument's response gradually rolls off for cloud 
droplets < 5 um and > 50 um; 50% points are ~2 um and ~70 um for LWC.

6. 1 HZ DATA - Each ~10 Hz ASTEX*.10 data file was averaged over ~1-s 
increments. A 1 Hz data file titled ASTEX*.lHZ was generated from each 
averaged file. The 1 Hz files contain LWC, PSA, and R(EFF) measured by the 
PVM. The 1 Hz files also contain LWC, PSA, R(EFF) found by summing the 
measurements of the PVM and the U. of Washington's OAP-200X drizzle probe 
that has 15 droplet size channels ranging from 20 um to 320 um. 
(The ~10 Hz data leads the 1 Hz data by 0.5 s, because the OAP-200X produces 
an output at the end of its 1-s sampling time.)

Given that the PVM has a gradual roll off in response for larger droplets, 
requires that only a portion of the output of each channel of the OAP-200X 
is used when summing with the PVM to determine the 1 Hz data. The estimated 
response of the PVM as a function of OAP-200X channel droplet diameter is 
as follows:

	OAP-200X	% Measured by PVM-10OA

	Channel	 Droplet	LWC Channel PSA Channel
	No.	 Size (um)


	1	 20 - 40	100		100
	2	 40 - 60	81		100
	3	 60 - 80	46		88
	4	 80 - 100	22		55
	5	100 - 120	12.3	    	33
	6	120 - 140	8.3		29
	7	140 - 160	6.0		26
	8	160 - 180	4.2		24
	9	180 - 200	3.2		22
	10	200 - 220	2		20
	11	220 - 240	2		18
	12	240 - 260	1		16
	13	260 - 280	1		12
	14	280 - 300	0		8
	15	300 - 320	0		6



SAMPLE DATA:    "ASTEX21 l0"


	FLT 1563	June 15	Interval	No. 21
	U.W. Time	frl61100	tol65000
	time	LWC	PSA     	r(eff)
	(S)	(g/m^3)	(cm^2/m^3)	(um)
	0.000	-0.008	-38.500		0.000
	0.102	-0.008	-38.497		0.000
	0.203	-0.008	-38.494		0.000
	0.305	-0.008	-15.391	    	0.000
	0.406	-0.008	-15.388		0.000
	0.508	-0.008	-15.385	    	0.000
	0.609	-0.008	-38.482	    	0.000
	0.711	-0.008	-38.479	    	0.000
	0.813	-0.008	-38.476		0.000
	0.914	-0.008	-15.373		0.000
	1.016	-0.008	-38.470		0.000
	1.117	-0.008	-15.367		0.000
	1.219	-0.008	-15.364		0.000
	1.320	-0.008	-15.361		0.000
	1.422	-0.013	-15.358		0.000
	1.524	-0.008	-15.355		0.000
	1.625	-0.008	-15.352		0.000
	1.727	-0.008	-15.349		0.000
	1.828	-0.008	-38.446		0.000
	1.930	-0.008	-15.343		0.000
	2.031	-0.008	-38.440		0.000



SAMPLE DATA:  "ASTEX21.lHZ"


FLT 1563        June 15 Interval      No.21     
U.W. Time      frl61100 tol65000       -- 

                                        WITH     WITH       WITH
                                      DRIZZLE   DRIZZLE    DRIZZLE
time     LWC      PSA        r(eff)      LWC      PSA      r(eff)
(s)     (g/m^3)  (cm^2/m^3)   (um)      (g/m^3)	(cm^2/m^3)  (um)
0.000    0.000    0.000       0.000     0.000     0.000     0.000
1.016   -0.008  -29.243       0.000     -0.008  -29.243     0.000
2.031   -0.009  -19.973       0.000     -0.009  -19.973     0.000
3.047   -0.008  -24.564       0.000     -0.008  -24.564     0.000
4.063   0.009    26.286       0.000     0.009    26.286     0.000
5.078   0.003    10.147       0.000     0.003    10.147     0.000
6.094   0.000    -1.373       0.000     0.000    -1.373     0.000
7.008   0.000    -2.886       0.000     0.000    -2.886     0.000
8.024   -0.001    0.224       0.000     -0.001    0.224     0.000
9.039   -0.002    0.255       0.000     -0.002    0.255     0.000
10.055  0.000    -1.256       0.000     0.000    -1.256     0.000