NSA/SONDE/C1 - Broken temperature sensor

It appears that the temperature sensor on this radiosonde broke after launch.  There is a 
sudden drop of 12 degC in 2 seconds and the remaining tdry values seem to be about 30 
degC low.

• Dry bulb temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative, at 21-m height, 30-min avg(rh)

NSA/SONDE/C1 - Broken temperature sensor

The temperature sensor on this radiosonde broke after launch
All the temperature-related data are incorrect.

• Dry bulb temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative, at 21-m height, 30-min avg(rh)

NSA/SONDE/C1 - This is a test sounding done using an RS80H radiosonde

This was a sounding done using an RS80H radiosonde to test a special operational 
procedure.  There is nothing wrong with the data, though users should be aware that the sounding 
was not done using the current ARM standard RS90 radiosonde.

• Wind Direction(deg)
• wstat
• Wind speed, S-to-N component, at altitude, derived from ETA model(v_wind)
• Altitude above mean sea level(alt)
• Dewpoint Temperature(dp)
• East longitude(lon)
• North latitude(lat)
• Humidity, relative, at 21-m height, 30-min avg(rh)
• time_offset
• asc
• base_time
• Dry bulb temperature(tdry)
• Wind speed, W-to-E component, at altitude, 915 MHz RWP(u_wind)
• Wind speed, surface, 1-min avg(wspd)
• Pressure, atmospheric, constant value of model level, RUC model output(pres)

NSA/SONDE/C1 - Test sounding using RS80H

This is a test sounding done using an old RS80H radiosonde rather than the production RS90 
version.  Although the sonde functioned normally, the RH data may be subject to a dry 
bias caused by the age of the sensor and possible contamination.

• Dewpoint Temperature(dp)
• Humidity, relative, at 21-m height, 30-min avg(rh)

NSA/SONDE/C1 - Incorrect surface altitude

The value of the station altitude (relative to mean sea level) is
incorrect in all NSA radiosonde files prior to 2/14/2004.  The correct
value is 8 m.  The incorrect value can be different.  Prior to 4/24/2002
(in platform nsaisssonde...) it was given as 12 m.  From 4/24/2002 to
2/13/2004 (in platform nsasondewnpn...) it is almost always given as
27 m (sometimes [rarely] 17 m).

• Altitude above mean sea level(alt)

NSA/SONDE/C1 - Bad temperature

Because of strong winds, the radiosonde hit the ground after launch and the temperature 
sensor broke.  The RH and pressure data also should be considered suspect.

• Wind Direction(deg)
• wstat
• Wind speed, S-to-N component, at altitude, derived from ETA model(v_wind)
• Altitude above mean sea level(alt)
• Dewpoint Temperature(dp)
• East longitude(lon)
• North latitude(lat)
• Humidity, relative, at 21-m height, 30-min avg(rh)
• time_offset
• asc
• base_time
• Dry bulb temperature(tdry)
• Wind speed, W-to-E component, at altitude, 915 MHz RWP(u_wind)
• Wind speed, surface, 1-min avg(wspd)
• Pressure, atmospheric, constant value of model level, RUC model output(pres)

NSA/SONDE/C1 - Noisy/Unstable RH and dew point data

The RH readings during the first 8 minutes of this sounding include three apparently 
incorrect oscillations to near-zero values.  After checking the absolutely raw data, it seems 
as though this period was excessively noisy, resulting in many missing values.  The noise 
abatted and the remaining sounding values are valid.

• Dewpoint Temperature(dp)
• Humidity, relative, at 21-m height, 30-min avg(rh)

NSA/SONDE/C1 - Bad surface RH and temperature values

This is a subtle problem that might escape notice.  For the identified sonde launches, the 
ground station lost its signal between the time it was removed from the ground check set 
and the time it was launched.  As a result, the software, which automatically determines 
the launch time and surface conditions at time of launch mistakenly used values of 
temperature and RH representative of the ground check set and the GW rather than of the 
ambient conditions before launch.  The bad values influenced only the first few samples and the 
remainder of the sounding values are correct.  

A procedural problem was identified and corrected.

• Dry bulb temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative, at 21-m height, 30-min avg(rh)

NSA/SONDE/C1 - RH values offset due to error in ground check

Background: After installation of the latest software update , we began performing formal 
ground checks on RS92 radiosondes.  By comparing the radiosonde readings with reference 
values in a controlled environment, the ground check is intended to ensure that the 
radiosonde sensors are in calibration before launch.  The radisonde values during the ground 
check process are recorded automatically; the reference values are entered by the operator. 
 If the radiosonde readings vary from the reference values, the system 'corrects' the 
radiosonde values.  In the case of RH, the correction is applied as an offset (true RH = 
indicated RH + correction).

Problem: Some operators misunderstood the ground-check procedure and entered the 
radiosonde values of RH rather than the reference value (assumed 0%RH), thus, some soundings done 
during this period have RH values that are different from what they would be if the 
ground check procedure had been done correctly.

Consequence:  Because the RH corrections generally are small (averaging about 0.5% RH) and 
the precision of the reported RH data during this time period is 1% RH, some values will 
not be affected at all; others will be off by about 1% RH (still within the stated 
accuracy of the sensor).  Furthermore, because entering the radiosonde value as the reference 
value results in a near zero 'correction,' one may view these soundings as being done 
without the ground check correction.  Also note that the dew point value will be suspect as well.

I am attaching below a listing of the soundings that were affected during the indicated 
time period.  Users can see the magnitude of the problem and choose whether or not to apply 
an offset in RH.  Note that application of the offset to the processed RH data (in the 
netCDF file) will not have the same effect of applying the correction to the absolutely 
raw data (before processing), but the differences should be insignificant.  Also note that 
the corrections for each sounding are included in the netCDF header information.  These 
attributes are named 'humidity_correction' and 'humidity_correction_2'.  The values of RH 
indicated by the radiosonde while it is in the ground check set are in attributes 
'humidity_gc_sonde' and 'humidity_gc_sonde_2.'  There is an RH reading for each of the two RH 
sensors used in the RS92 radiosonde.

Here is the list - RH1 and RH2 are the radiosonde readings in the ground check set.  Ref 
is the reference value entered by the operator.  The correcte reference value should be 
0%.  To obtain an approximation to the RH value that would have been recorded if the ground 
check had been done properly, subtract the Ref value from the indicated RH.

 YYYYMMDD  HHMM  SerialNo     RH1     RH2     Ref
 20060713  0532  B1924431    0.30    0.20    0.30
 20060713  1751  B1854963    0.20    0.30    0.30
 20060714  0521  B1924425    0.40    0.40    0.40
 20060714  1739  B1854206    0.30    0.30    0.30
 20060715  0522  B1715127    1.20    1.20    1.20
 20060715  1737  B1854966    0.60    0.60    0.60
 20060716  0508  B1715126    0.40    0.40    0.40
 20060716  1732  B1844098    0.50    0.50    0.50
 20060717  0517  B1914170    0.40    0.40    0.40
 20060718  0516  B1914173    0.70    0.70    0.70
 20060720  0523  B1854149    0.40    0.40    0.40
 20060721  0517  B1914153    0.40    0.40    0.40
 20060722  0521  B1844097    1.00    1.10    1.10
 20060722  1730  B1914174    0.60    0.70    0.70
 20060723  0537  B1714439    0.40    0.40    0.40
 20060723  1734  B1734155    0.50    0.50    0.50
 20060724  0529  B1134336    0.50    0.50    0.50
 20060725  0525  B1754099    0.60    0.70    0.70
 20060726  0541  B1844108    1.80    1.80    1.80
 20060727  0520  B1714382    0.70    0.80    0.70
 20060728  0531  B1854116    0.80    0.80    0.80
 20060729  0527  B1724027    1.00    1.00    1.00
 20060729  1726  B1714392    0.70    0.80    0.80
 20060730  0522  B1854100    0.70    0.80    0.80
 20060730  1724  B1854764    0.90    1.00    1.00
 20060731  0515  B1664086    0.90    0.80    0.90
 20060801  0520  B1724758    1.50    1.50    1.50
 20060801  1729  B1754116    1.10    1.10    1.10
 20060802  0518  B1724516    0.80    0.80    0.80
 20060803  0523  B1674148    0.80    0.80    0.80
 20060804  0532  B1754092    0.90    0.90    0.90
 20060804  1727  B1844117    3.50    3.50    3.50
 20060805  0531  B1714741    0.30    0.30    0.30
 20060805  1728  B1754098    0.30    0.30    0.30
 20060806  0528  B1844115    0.40    0.40    0.40
 20060806  1728  B1914161    0.20    0.20    0.20
 20060807  0530  B1714549    0.30    0.30    0.30
 20060808  0517  B1844107    0.50    0.50    0.50
 20060808  1744  B1914166    0.20    0.20    0.20
 20060809  0527  B1914164    0.30    0.40    0.40
 20060809  1736  B1914163    0.30    0.30    0.30
 20060810  0521  B1914160    0.40    0.50    0.50
 20060810  1745  B1744671    0.40    0.40    0.40
 20060811  0525  B1854965    0.50    0.50    0.50
 20060811  1753  B1724131    0.10    0.10    0.10
 20060812  0527  B1754104    0.50    0.50    0.50
 20060812  1740  B1854256    0.30    0.40    0.40
 20060813  0522  B1854240    0.30    0.40    0.40
 20060814  0525  B1714106    0.20    0.20    0.20
 20060814  1742  B1854106    0.40    0.40    0.40
 20060815  0534  B1914169    0.50    0.60    0.60
 20060815  1734  B1854233    0.60    0.70    0.70
 20060816  0539  B1724791    0.20    0.20    0.20
 20060816  1732  B1914171    0.10    0.20    0.20
 20060817  0535  B1354283    0.10    0.10    0.10
 20060817  1740  B1354574    0.40    0.40    0.40
 20060818  0516  B1354633    0.50    0.40    0.50
 20060818  1744  B1364673    0.20    0.20    0.20
 20060819  0538  B1364126    0.20    0.30    0.30
 20060819  1745  B1354598    0.50    0.60    0.60
 20060820  0532  B1354290    1.10    1.10    1.10
 20060820  1729  B1354317    0.40    0.40    0.40
 20060821  0530  B1354545    0.60    0.70    0.70
 20060821  1728  B1354516    0.70    0.70    0.70
 20060822  0524  B1354619    0.50    0.60    0.60
 20060822  1728  B1364377    0.40    0.40    0.40
 20060823  0533  B1354309    0.30    0.30    0.30
 20060823  1730  B1354527    0.70    0.70    0.70
 20060824  0533  B1354230    0.60    0.60    0.60
 20060824  1812  B1354587    0.70    0.70    0.70
 20060825  0517  B1354614    0.70    0.70    0.70
 20060825  1730  B1354630    0.60    0.60    0.60
 20060826  0537  B1334114    0.90    0.90    0.90
 20060826  1734  B1354246    0.70    0.70    0.70
 20060827  0508  B1354534    0.70    0.70    0.70
 20060827  1729  B1354618    0.60    0.60    0.60
 20060828  0517  B1354115    0.40    0.40    0.40
 20060828  1738  B1354206    0.50    0.60    0.60
 20060829  0516  B1354617    0.50    0.60    0.60
 20060829  1717  B1354622    0.50    0.60    0.60
 20060830  0511  B1354314    0.40    0.50    0.50
 20060830  1732  B1354537    0.60    0.70    0.70
 20060831  1802  B1354239    0.60    0.80    0.80
 20060905  1724  B1354626    0.60    0.60    0.60
 20060906  0522  B1354525    0.60    0.80    0.80
 20060906  1734  B1354107    0.50    0.50    0.50
 20060907  0537  B1354543    0.70    0.70    0.70
 20060907  1803  B1354586    0.80    0.80    0.80
 20060908  0531  B1354519    0.60    0.60    0.60
 20060908  1728  B1354224    0.60    0.60    0.60
 20060909  0534  B1354532    0.70    0.80    0.80
 20060909  1732  B1354513    0.80    0.90    0.90
 20060910  0516  B1354125    0.60    0.70    0.60
 20060910  1727  B1354110    0.40    0.50    0.50
 20060911  0528  B1354235    0.90    0.90    0.90
 20060911  1849  B1354514    0.70    0.70    0.70
 20060912  0525  B1354124    0.60    0.70    0.70
 20060913  0534  B1344478    0.50    0.50    0.50
 20060914  0520  B1354226    0.70    0.70    0.70
 20060915  0529  B1344459    0.40    0.50    0.50
 20060916  0532  B1344469    0.50    0.40    0.50
 20060916  1732  B1354106    0.50    0.60    0.60
 20060917  0527  B1354210    0.70    0.70    0.70
 20060918  0533  B1354087    0.60    0.60    0.60
 20060919  0526  B1354097    0.70    0.50    0.60
 20060920  0516  B1344462    0.50    0.40    0.50
 20060920  1810  B1354536    0.70    0.70    0.70
 20060921  0534  B1354112    0.50    0.60    0.60
 20060921  1800  B1344502    0.40    0.40    0.40
 20060922  0525  B1354531    0.70    0.80    0.80
 20060922  1736  B1354541    0.70    0.70    0.70
 20060923  0519  B1354101    0.50    0.60    0.60
 20060923  1738  B1354576    0.70    0.50    0.70
 20060924  0536  B1354095    0.60    0.60    0.60
 20060925  0536  B1354098    0.60    0.60    0.60
 20060925  1755  B1354100    0.50    0.50    0.50
 20060926  0531  B1334691    0.70    0.70    0.70
 20060926  1742  B1354108    0.40    0.50    0.50

• Dewpoint Temperature(dp)
• Humidity, relative, at 21-m height, 30-min avg(rh)

NSA/SONDE/C1 - Incorrect surface values of T and RH

The radiosonde was launched too quickly after being removed from the ground check set.  As 
a result, the system did not equilibrate with the local ground conditions and the 
automatically entered surface values are incorrect.

• Dry bulb temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative, at 21-m height, 30-min avg(rh)

NSA/SONDE/C1 - RH sensor failure

It appears that one of the two RH sensors on this radiosonde was affected by ice after 
emerging from a low cold cloud.  As a result the reported RH values oscillate by about 10 
percent until the alternate heating cycle stops.  I suspect the lower value is more close 
to correct, but can't be absolutely sure.

• Dewpoint Temperature(dp)
• Humidity, relative, at 21-m height, 30-min avg(rh)

NSA/SONDE/C1 - Incorrect surface RH value

For an unknown reason the surface RH was reported a 0%.  Becuase these values are entered 
automatically by the system, this is NOT likely an operator error.  Examination of the 
raw data shows that the surface RH at launch time was approximately 81.2 %RH.

• Dewpoint Temperature(dp)
• Humidity, relative, at 21-m height, 30-min avg(rh)

NSA/SONDE/C1 - Temperature sensor broke at launch

The temperature sensor on this sonde broke at launch.  As a result all the thermodynamic 
data are incorrect.  The wind data are OK, though there will be some uncertainty in the 
altitude values.  This sounding was done at a non-standard time and it isn't clear whether 
it was delayed for some reason or a RHUBC sounding.  In either case, there is no fix.

• Altitude above mean sea level(alt)
• Dry bulb temperature(tdry)
• Dewpoint Temperature(dp)
• Humidity, relative, at 21-m height, 30-min avg(rh)
• asc

NSA/SONDE/C1 - Wind data missing

A GPS problem associated with Vaisala BBSS ground station software issues caused the 
ground stations to enter into an error state when using GPS wind finding. In some instances, 
the flight was aborted due to the error state and not data was collected.  A workaround 
was developed to allow sondes to be launched without collecting wind data.

• Wind speed, S-to-N component, at altitude, derived from ETA model(v_wind)
• wstat
• Wind speed, W-to-E component, at altitude, 915 MHz RWP(u_wind)
• Wind speed, surface, 1-min avg(wspd)

NSA/SONDE/C1 - Wind data missing

After some power disruptions, the Power Supply board of the SPS220 ground station was 
damaged.  The damage caused the supply to not have enough power to run the GPS board.  
Switching to the back up DigiCora II did not alleviate the problem as the fix for GPS failure 
to all Vaisala sonde products had not been installed.  A different P/S was found and sent 
up to replace the failed one.

• Wind Direction(deg)
• Wind speed, S-to-N component, at altitude, derived from ETA model(v_wind)
• Wind speed, W-to-E component, at altitude, 915 MHz RWP(u_wind)
• Wind speed, surface, 1-min avg(wspd)

NSA/ARSCL/C1 - Reflectivity values unreliable

Reflectivity dBZ values should not be used.  The reported cloud boundaries may 
underestimate cloud tops, particularly for high or thick clouds.  Also thin high clouds may have 
been missed entirely, especially if there were lower-level cloud layers below them. During 
this time period, the MMCR was transmitting in  circular polarization, rather than 
(correct) linear polarization. This caused reported Reflectivity values to be too low by an 
unknown amount, resulting in an effective loss of radar sensitivity.

Areas identified as have having hydrometeor detections are correct, however some areas 
marked as clear may in fact contain cloud due to the MMCR's low sensitivity during this time.

• CloudLayerTopHeightMplCloth
• MMCR Reflectivity, Best estimate, Hydrometer(ReflectivityBestEstimate)
• RadarFirstTop
• Reflectivity(Reflectivity)
• MMCR Reflectivity, clutter removed(ReflectivityNoClutter)
• CloudLayerBottomHeightMplCloth

NSA/AOS/X1 - Data processing problem

The AOS data was reprocessed for the AMF, SGP and NSA sites. There was an error in the 
processing of the corrections for the PSAP absorption signal such that a low pass filter was 
implemented for the scattering data used in these corrections.The difference between the 
corrected and previous data is < 0.05 Mm-1 (below the instrument detection limit) and 
should not have a significant effect on the previous data.Data will be reprocessed at a 
later time when more significant changes to the data processing are implemented.

• Absorption coefficient green, corrected for flow and sample area, 3 wavelength
  PSAP, 1 um size cut(Ba_G_Dry_1um_PSAP3W_1)
• Aerosol light absorption coefficient, green channel, 10 um particle diameter(Ba_G_Dry_10um_PSAP1W_1)
• Absorption coefficient blue, corrected for flow and sample area, 3 wavelength
  PSAP, 1 um size cut(Ba_B_Dry_1um_PSAP3W_1)
• Absorption Coefficient Blue, corrected for flow and sample area, 3 wavelength
  PSAP, 10 um size cut(Ba_B_Dry_10um_PSAP3W_1)
• Absorption coefficient, green wavelength, 3 wavelength PSAP, low RH, 10 um size
  cut(Ba_G_Dry_10um_PSAP3W_1)
• Absorption Coefficient Red, corrected for flow and sample area, 3 wavelength
  PSAP, 10 um size cut(Ba_R_Dry_1um_PSAP3W_1)
• Absorption coefficient, green wavelength, low RH, 1 um size cut(Ba_G_Dry_1um_PSAP1W_1)
• Absorption coefficient red, corrected for flow and sample area, 3 wavelength
  PSAP, 10 um size cut(Ba_R_Dry_10um_PSAP3W_1)

NSA/ARSCL/C1 - Reflectivity too high

The calibration of the MMCR was incorrect during this period, causing large positive 
shifts in reported reflectivity values.  As a result, the reflectivies reported by ARSCL are 
also too high.  However, other radar moments (MeanDopplerVelocity and SpectralWidth) and 
cloud boundaries reported in ARSCL data files are not affected and can be used.

Do not use ReflectivityBestEstimate, Reflectivity, or ReflectivityNoClutter values during 
this period.

• MMCR Reflectivity, Best estimate, Hydrometer(ReflectivityBestEstimate)
• Reflectivity(Reflectivity)
• MMCR Reflectivity, clutter removed(ReflectivityNoClutter)