Blog from June, 2013

8:00 -   Tsoil.b 0.6cm just failed as the rain started.

Weather: Cloudy, potential rain today

Summary: Tsoil 4.4cm a & b out, tsoil.b 3.1cm questionable. Plan to use new Tsoil at b.

a few rain events from WXT this morning, ~7:00.

Sonics: ok

TRH, P: ok

Wind Speed & Dir: ok

Soil, Rainr: ok, Tsoil 4.4cm a & b out, 3.1cm on tsoil.b questionable, 0.6cm a6 Tsoil b failed

Vmote (rad, a, a2, b): 11.7,12.1,11.7, 12.4

Radiation, Wetness: ok

H2O, CO2: ok

System (GPS, Vdsm): ok

Pond:ok

This morning, I installed our last spare Tsoilx4 at soil.b.  However, I want to give it some time to settle before using it.  So, swapped connections with the old Tsoil.b from 10:50-11:02 (note that the new probe has ID23) to get a baseline difference.  I then went back to the old Tsoilx4.  My plan is to do the real switch tomorrow.

 Decided to make a LAI measurement this morning since there was good cloud cover. While making the measurements the skies started clearing so this data set, 6/23/13, should be used with caution.

Below is a table of when LAI-2000 measurements were taken on the tower.

We have determined that a ~4' black rat snake lives in a crack in the concrete near the back steps of the base trailer.  Completely harmless (if you are not a rodent).

Instructions for LAI-2000 vertical profiles

Sensor Setup

1. Grab the “A” sensor and control unit. Plug sensor into “X” port on the control unit.
2. 2.       Ensure that the sensor head is clean and the 270° view-cap is correctly oriented (such that it blocks the user). If the sensor head is dusty or has fingerprints, use the cleaning supplies in the box to clean (brush, poofer, lens wipes + fluid).
3. Push ON key.
4. Push LOG.
5. Push ENTER to confirm “WHERE” as AABC.
6. Use keys to enter the next increment for the “WHAT” identifier (V1, V2, V3, etc. for vertical profiles). Remember that the ? key must be pushed to enter a letter.

Measurements

1. Gear up. Don’t forget to stretch!
2. Climb to 38 m.
3. Hold the sensor out from the tower. Orient it such that it is not exposed to direct sunlight (e.g. W if morning, E in evening). Note compass direction.
4. Level the sensor (roughly is OK).
5. Push and release the button on the handle to take a measurement. You will hear 2 beeps. If you don’t, it is likely that the sensor is disconnected. Reconnect and try again.
6. Repeat steps 3 – 5 at every flux level. Point sensor in the same compass orientation every time.
7. When done, push BREAK.
8. Push FCT 09 to turn off the control unit.
9. Please log the time, V# and direction in which measurements were taken in a spreadsheet.

Downloading Data

Note: This can wait until the end of the campaign.

1. Install FV2200 software on your computer.
2. Attach the RS-232 port on the LAI-2000 control unit to a computer serial or USB port.
3. LAI-2000: push ON.
4. LAI-2000: push FCT 21. Note number of files.
5. Run the FV2200 executable and click “Acquire”. Follow the on-screen prompts.
6. LAI-2000: when prompted to print files (after FCT 32), enter:
   1. FROM: 1
   2. THRU: [total number of files]
   3. Make sure that data is saved on your computer. If not, you will have to use “saveAs” in FV2200.
   4. Send the data to Glenn Wolfe: gwolfe@umbc.edu, along with the log-book spreadsheet.
   5. Thanks!

Notes

-          Measurements are best done when the sun is low: before 9 AM or after 6 PM. Optimal conditions are a uniform sky (i.e.  all blue or all grey), but this is not essential given that vertical profile does not take long to acquire.

-          Avoid taking measurements in direct sunlight. You can shade the sensor (e.g. with your hand) from directly behind it. The view-cap prevents this region from being included in the measurement.

-          It would be nice to have measurements from multiple directions.

-          If you ever mis-enter a command on the LAI 2000, just push BREAK to start over.

Weather: Partly cloudy

Summary: Tsoil 4.4cm a & b out, tsoil.b 3.1cm questionable. May change batteries on rad and a2. Rain event shown on

rainr.ott at about 20:30 last night.

Sonics: ok

TRH, P: ok

Wind Speed & Dir: ok

Soil, Rainr: ok, Tsoil 4.4cm a & b out, 3.1cm on tsoil.b questionable

Vmote (rad, a, a2, b): 11.8, 12.2, 11.9, 12.7

Radiation, Wetness: ok

H2O, CO2: ok

System (GPS, Vdsm): ok

Pond: ok

I had speculated at this week's Science Meeting that canopy storage (in particular moisture) should be large to balance the surface energy budget.  I've just run a quickee calculation from yesterday (a mostly clear-sky case).  I simply linearly averaged the in-canopy measurements in this calculation.

I get that, at night, the canopy loses heat at about -20 W/m2.  During the morning, the canopy gains heat at up to 50 W/m2.  During the day, there are large changes, but the long-term average is zero, with a tendency for the top of the canopy to heat while keeping moisture constant and the bottom of the canopy to cool while gaining moisture.  To first order, sensible and latent heat storage are about the same (each about half of the total storage) in the night and morning, and equal and opposite during the day.  The average storage over the entire day was 0!  

All of this seems entirely plausible to me, but it this doesn't explain the energy imbalance (not surprising from EBEX).  Guess we'll have to hypothesize horizontal advection...

8:50 - Battery replaced at soil.b. The solar charger has been disconnected from the battery. The thought

is the charger may be taking more juice than we are getting from the sun. Battery went from 6.6v to 12.9v.

Weather: Clear skies

Summary:  Battery at soil.b low, Tsoil 4.4cm a & b bad.

Sonics: ok

TRH, P: ok

Wind Speed & Dir: ok

Soil, Rainr: ok, Tsoil 4.4cm a & b out

Vmote (rad, a, a2, b): <9 to 12.4, soil.b dropping fast

Radiation, Wetness: ok

H2O, CO2: ok

System (GPS, Vdsm): ok

Pond: ok

Every night, and even some of the day, I see what look like waves in the wind speeds at the top of the tower.  However, I don't see corresponding waves in the scalars.  Perhaps there is a hint in pressure, but it isn't obvious.  Not sure what this is at the moment.

Driving back from Jim's, there were drops on our windshield.  The WXT and wetness sensors have seen it.

From about 1030-1200, Steve and I were at the tower:

- Take in 3 links on #5 NW guy to allow us to tension.  Adjusted top 3 guy sets to straighten tower.  See guy wire entry that Steve is updating.

- Shoot boom angle: 263.6 degrees by me (looking into boom).  (North set to zero in Datascope.)  I wouldn't be surprised if this is a degree off...

- Took soil samples at about 1200 and immediately drove to lab for processing.  I'll update the soil logbook entry as well.

Weather: Clear skies

Summary:  Everything looking good. Soil.a2 stopped for about 2 hours last night and

there were a few ldiag jumps on the 43.9m sonic. Tsoil 4.4cm a& b bad.

Sonics: ok, a few ldiag on 43.9m last night

TRH, P: ok

Wind Speed & Dir: ok

Soil, Rainr:  Soil,a2 went down from 0:00 to 3:00, 4.4cm tsoil on a & b out

Vmote (rad, a, a2, b): 11.4 to 12.6, soil.b lowest

Radiation, Wetness: ok

H2O, CO2: ok

System (GPS, Vdsm): ok

Pond: ok

Just was out from about 1245-1300:

- reseated connectors for Qsoil.b (both binder and DIN).

- cleaned a small amount of gunk from tipping bucket tube.  During this process, there was one tip of "delayed" rain (water was dumped out of the tipper).

- mounted PAR.2m in its final position.  Have just added "Rpar.2m" to the config and restarted dsm_server.

- Swapped soil.a battery yet again.  This time, swapped out the (somewhat broken) console cable.  Also disconnected the internal red wire from the charging circuit, so this isn't being charged by the solar panel.  (Also need to remember to reconnect when charging it up in the base.)  We'll see if this improves the discharge rate of batteries at this site.

- Did a final rescan of soil.b, just in case....