https://atmoswiki.azurewebsites.net/ 2026-04-19T19:44:31+00:00 https://atmoswiki.azurewebsites.net/ https://atmoswiki.azurewebsites.net/lib/exe/fetch.php?media=wiki:favicon.ico text/html 2020-01-29T17:25:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://atmoswiki.azurewebsites.net/doku.php?id=atmos:citation:instruments:tdl:2005_summer&rev=1580318748&do=diff Summer 2005 Instrument Calibration After the Sikorksy II field project the TDL instrument was sent in to get a new calibration. A TDL calibration check was done on July 5, 2005 and a TDL leak check was done on July 6, 2005. During the leak check, the TDL was pump up to 6 in Hg and watched until it drop to 5 in Hg. Total time to drop was 1 minute. After these test, the TDL would not output any water vapor concentration numbers. text/html 2020-01-29T17:25:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://atmoswiki.azurewebsites.net/doku.php?id=atmos:citation:instruments:tdl:2006_spring&rev=1580318748&do=diff Zero Mixing Ration Reading The TDL always gives 0.01 ppmv for a mixing ratio value. Looking at the Com 1 output using PCAnywhere indicates that the TDL starts up fine with measurements after the 30 second warm up period. The output shows a beerfactor of about 1.8 which would seem to indicate that it is getting a reasonable humidity measurement. When investing, it was noticed that the board stack was not very well connected to the bottom of the instrument. 2 of the 4 screws were missing and the … text/html 2020-01-29T17:25:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://atmoswiki.azurewebsites.net/doku.php?id=atmos:citation:instruments:tdl:2015_leak&rev=1580318748&do=diff 2015 TDL Tubing Leak Problem * Cleaned the TDL on 13 October, 2015 and the dewpoint from the TDL was close to the dewpoint from the Edgetech chilled mirror. During the clear flights from Grand Forks, ND to Great Falls, MT and then from Great Falls, MT to Everett, WA the TDL did not respond to atmospheric moisture changes above some altitude. Cleaned the TDL again on 9 November 2015, but the TDL had the same response. Figure 1 shows an example of the TDL not responding to changes in atmosp… text/html 2025-08-05T14:55:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://atmoswiki.azurewebsites.net/doku.php?id=atmos:citation:instruments:tdl:home&rev=1754405711&do=diff Tunable Diode Laser Hygrometer (TDL) * Description: Laser Hygrometer * Manafacturer: Maycomm Research Company * Model Number: AC19-400 * UND Tag Number: 103510 * Calibration Mixing Ratio Equations: * TDL mixing ratios ≥ 4801.7 ppmv: w = 10^{1.2649*(log text/html 2020-01-29T17:25:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://atmoswiki.azurewebsites.net/doku.php?id=atmos:citation:instruments:tdl:iop1&rev=1580318748&do=diff IOP - Summer 2004 IOP flights at UND the dew point temperature was high compared to the measured air temperature. Cause Bad calibration information in the instrument from the Spring 2004 calibration. Solution Send the instrument in to get recalibrated. September 2, 2004 ground check by David Delene shown that the instrument was working a lot better. Comparison with dewpoint generator shown measured dewpoint of 9.6 C when a dewpoint of 10 C was generated. September 24, 2004 Test flight in Gr… text/html 2020-01-29T17:25:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://atmoswiki.azurewebsites.net/doku.php?id=atmos:citation:instruments:tdl:sikorsky&rev=1580318748&do=diff Sikorsky After the L3Com project the TDL instrument was found to have a leak. The leak was fixed and a new calibration for the instrument obtained that was to be applied in the Citation data processing and not in the TDL instrument itself. On the several of the Sikorsky flights the TDL dewpoint temperature was high compared to the temperature when in cloud. text/html 2024-09-19T13:32:27+00:00 Anonymous (anonymous@undisclosed.example.com) https://atmoswiki.azurewebsites.net/doku.php?id=atmos:citation:instruments:tdl:tdl_cleaning&rev=1726752747&do=diff TDL Cleaning Procedure * This follows the cleaning procedure sent to Mike Poellot from John Buetow. * It is helpful to have a little jar or cup to hold all the bolts that hold the TDL together. * This whole cleaning procedure takes about 2-3 hours from start to finish. text/html 2020-01-29T17:25:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://atmoswiki.azurewebsites.net/doku.php?id=atmos:citation:instruments:tdl:tdl_inlet&rev=1580318748&do=diff TDL Inlet Image to the TDL inlet on May 24, 2014. The height of the inlet tube is 6 inch and the length backwards is 5 inch. text/html 2020-01-29T17:25:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://atmoswiki.azurewebsites.net/doku.php?id=atmos:citation:instruments:tdl:tdl_laptop_comm&rev=1580318748&do=diff TDL - Laptop Communications COM 1 Communications (Two-way) * Need laptop with Symantec's PCAnywhere software (Version 9.2 or lower) * Need null modem * Connect laptop to TDL COM 1 port with null modem serial cable * Start PCAnywhere software text/html 2025-08-06T15:09:31+00:00 Anonymous (anonymous@undisclosed.example.com) https://atmoswiki.azurewebsites.net/doku.php?id=atmos:citation:instruments:tdl:tdl_monitor_setup&rev=1754492971&do=diff TDL Monitor Setup This page gives step by step instructions to connect the TDL to a monitor to further access the TDL's on board computer. * Step 1: Start by getting appropriate supplies to connect the TDL to a monitor. This includes the connector between the TDL's computer board to VGA output which can be found in the TDL supplies box, a keyboard with a DIN connector, a VGA female to female extension cable, and a monitor with a VGA port.