Upper Air Training Session

February 2009

Upper Air Meeting

• NOOOOOOO!

• Updates to RRS Workstation User Guide

• Stay fresh on what to do when problems arise

Release Times• Synoptic flights

– Ob time (H) minus 60 min– Example: release for 12Z ob should occur at

11Z– Release window: H-60 to H+30 (1 ½ hr to

get a balloon up)• Special flights

– H-30 min– Example: release for 18Z ob should occur at

1730Z– Release window: H-30 to H+30 (1 hr to get

a balloon in the air)• If release is detected even one second

early or late, ob time will be logged differently

Release Times Cont’d

• If you release outside of the release window:– Do not edit the messages or release

time; let the software do its thing– Make a note in the remarks section of

the B-29 and UA2009 that you released too early or too late

Message Transmission Times• Parts A and B

– No later than H+60 min– Ex: A and B messages for a 12Z flight

should be transmitted by 13Z– Typically ready by H+15 min

• Parts C and D– No later than H+150 min (2 hr 30 min)– Ex: for a 12Z flight, should be

transmitted by 1430Z– Typically ready by H+60 min

No GPS At Baseline

• Before you reject…1. Verify the signal strength and that the

bottom status bar is indicating GPS height

1. Disconnect/reconnect battery

2. Reset the SPS (Click “SPS Reset” button on the Hardware Status Display

3. Click “Power On/Off UPS” button the Hardware Status Display

• If all of these steps fail to produce GPS data, reject the instrument

RRS Doesn’t Recognize Release• Click the manual release icon (little man

holding yellow balloon)

• Flashing blue screen says “Release Detected”…click O.K.

• Look at the “Received PTU” display to determine where pressure continually decreased

• Change release time– Click “Tools” → “Release Time” → put in correct

release time → click “OK”

Missing Data

• Caused by signal loss (if all PTU data is missing)

• Signal loss can be caused by several things– Frequency shift– Antenna not tracking properly

• locked on to sidelobe• MCU overload (antenna locks up)

– Radiosonde or battery failure

Missing Data Checklist

• Signal Strength

• Frequency

• TRS status display

Missing Data Checklist Cont’d

– “Tracking is suspended”• Antenna has locked up and will need to

be reset; could take up to two min• After antenna is reset, place in “Search”

mode• Verify the signal strength

– “TRS is ready”• Antenna has likely locked on to a

sidelobe or shifted off of the signal• Place antenna in “Search” mode • Verify that the signal strength returns

Superadiabatic Lapse Rates

• RRS generates check messages for all supers– ≥ 34◦C/km within 1 km of surface– ≥ 15◦C/km beyond 1 km

• If there is a check message for a superadiabatic lapse rate – fix it!– Do not smooth more than 1 minute

Wet Bulb Effect

• Evaporative cooling on the temp sensor causes erroneous superadiabatic lapse rates– Sonde travels through saturated layer– Condensation forms on temp sensor– Sonde travels through dry layer– Water evaporates off of the sensor,

absorbing latent heat– Temp sensor experiences a “cooling

sensation”

Wet Bulb Effect Cont’d

• Delete all erroneous temps until check messages go away– More than 3 minutes: terminate the

flight

More Wet Bulb Effect

RH Problems

• Dry Bias– ERRONEOUS Rapid drying off the

surface– Mark up to 1 min of data

• Layers of 1% RH– Less than 15 min: leave it alone– More than 15 min: delete all RH data

from the beginning of the 1% through termination

• Erratic RH data– Delete it!

Wind Problems

• Common to see “Check” messages for wind direction/speed changes– 12 or more check messages:

• Compare winds to profilers and the previous flight

• If winds are not reasonable, delete all erroneous winds

• Missing Winds– More than a few minutes, notify SDM

and the Lead Forecaster– Both can request a second release

Tips to Avoid Problems

• Always verify signal strength and frequency immediately prior to and after release

• To avoid TRS lock-up– EL angle ≥ 60◦, the antenna in should

be in “Manual” track mode

• Be sure to correctly prepare the battery and radiosonde– Prepare the battery properly

• Soak for 2 min

Tips to Avoid Problems Cont’d

• Soak at the proper time• Always shake the battery out with 10 arm

swings outside• Change the battery water before the 00Z

flight soaking

– Make sure the temp boom is positioned at a 90◦ angle

• Always “Calculate” and “Accept” your baseline values before release

• Check the “Thanks” report

B-29 and Spreadsheet Remarks• Significant wx at release, especially

when using extra gas

• Any problems with the flight or equipment

• When a 2nd or 3rd release occurs

• Radiosondes are rejected

• If the flight is a special flight, note who requested it and why

Odds and Ends

• Caps on cylinders if not connected to supply hose

• Tell us if supplies are needed