MAP 1999: SABL Known Problems

Frequent problems with the latitude and longitude occur in the data. Either the latitude and longitude are set to 0 or they appear to get "stuck" on some value. To solve this problem, the latitude and longitude can be merged into the data from the RAF netCDF files.

There was a problem with the date on most tapes. In general, the very first date written on the tape is good, and then the date goes bad when the first 95 MByte file mark is written. On all flights, the "Julian" (actual day of year) date is correct.

The IR channel is "noisier" than the Green channel.

There is "ringing" in the IR channel that is visible in the noise.

In all SABL data taken through MAP (November 1999) the sample rate labeled 40 MHz was actually slightly more than 42 MHz. If the sample rate were truly 40 MHz, the gate spacing would be 3.75 meters. However, the actual sample rate made the true gate spacing about 3.53 meters. The gate spacing is correct as given for all other sample rates than 40 MHz.

The range delay (the time between when the first sample is taken and when the laser pulse actually happens) was measured and is correct on all projects except INDOEX and MAP. On these projects the first gate is sampled 106.4 m before the laser pulse. So, the true distance to a gate, when the sampling rate is 40 MHz is given by:

d = -106.4 + 3.53 * gate_number.

The gate number should start with 0. The -106.4 m range delay will hold for all sample rates. So, for example, the distance to a gate sampled at 30 MHz would be calculated by:

d = -106.4 + 5.0 * gate_number.

FLIGHT

DATE

TIME

PROBLEM

RF01

15-Sep-99

14:05-17:38

1. Month reverts to August after first file mark.

RF02

19-Sep-99

10:59-13:57

1. Month reverts to August after first file mark.

RF03

20-Sep-99

05:06-10:17

1. Month reverts to August after first file mark.

RF04

20-Sep-99

12:09-15:51

1. Month reverts to August after first file mark.

RF08

01-Oct-99

08:15-14:17

1. Day reverts to previous day after first file mark.

RF09

02-Oct-99

10:12-13:26

1. Day reverts to previous day after first file mark.

RF10

04-Oct-99

06:55-11:47

1. Day reverts to previous day after first file mark.

RF11

13-Oct-99

13:34-17:23

1. Day reverts to previous day after first file mark.

RF12

18-Oct-99

13:32-18:20

1. Day reverts to previous day after first file mark.

RF13

20-Oct-99

11:23-14:04

1. Day reverts to previous day after first file mark.

RF14

21-Oct-99

06:13-11:46

1. Day reverts to previous day after first file mark.

RF15

23-Oct-99

07:04-09:13

1. Very little data collected due to tape drive malfunction.

RF16

24-Oct-99

13:04-15:40

1. Day reverts to previous day after first file mark.

RF17

30-Oct-99

08:16-11:07

1. Day reverts to previous day after first file mark.

RF18

29-Oct-99

13:50-18:11

1. Day reverts to previous day after first file mark.

RF19

01-Nov-99

13:04-15:19

1. Day reverts to previous day after first file mark.

RF20

01-Nov-99

07:51-11:55

1. Day reverts to previous day after first file mark.

RF21

03-Nov-99

12:21-16:02

1. Day reverts to previous day after first file mark.

RF22

04-Nov-99

12:06-16:49

1. Day reverts to previous day after first file mark.

RF23A

06-Nov-99

07:48-09:22

1. Day reverts to previous day after first file mark.

2. Problems with the UPS resulted in time gap. New tape started.

RF23B

06-Nov-99

09:39-10:17

1. Day reverts to previous day after first file mark.

RF24

06-Nov-99

14:23-18:31

1. Day reverts to previous day after first file mark.

RF25

07-Nov-99

13:06-18:02

1. Day reverts to previous day after first file mark.

RF26

08-Nov-99

10:24-14:37

1. Day reverts to previous day after first file mark.

RF27

11-Nov-99

10:19-15:29

1. Day reverts to previous day after first file mark.

RF28

12-Nov-99

12:06-14:58

1. Day reverts to previous day after first file mark.

RF29

13-Nov-99

11:48-15:35

1. Day reverts to previous day after first file mark.