SGP/SONDE/C1 - Mixed use of RS92-SGP and RS92-KL radiosondes

Because of a manufacturer's production problem, we will be using both RS92-SGP (GPS 
windfinding and RS92-KL (Loran windfinding) radiosondes at the SGP/CF starting February 10, 
2006.  The radiosonde type used for the each sounding may be determined by looking the 
metadata variable "launch_status" in the netCDF data files.

• east longitude for all the input platforms.(lon)
• model zonal wind velocity(u_wind)
• surface wind speed(wspd)
• model meridional wind velocity(v_wind)
• north latitude for all the input platforms.(lat)
• Wind Direction(deg)
• Wind Status(wstat)

SGP/SONDE/C1 - Increased precision for alt, dp, pres, rh, tdry

The output precision of the following variables was increased 20060928

alt  changed from 1m to 0.1m
dp   changed from 0.1degC to 0.01degC
pres changed from 0.1 hPa to 0.01 hPa
RH   changed from 1%RH to 0.01%RH
tdry changed from .1degC to 0.01degC

Note that the increase in precision does not necessarily imply an increase in accuracy.  
Users are cautioned to continue to use their best scientific judgement when using these or 
any other data.

• Surface dew point temperature(dp)
• Dry-Bulb Temperature(tdry)
• Relative humidity scaled, by total column amount from MWR(rh)
• pressure at constant pressure surface(pres)
• altitude above sea levelaltunits(alt)

SGP/SONDE/C1 - RH Sensor failure

The differences between the two RH sensors on this sonde are unreasonably high (~20%).  As 
a result the reported RH values oscillate by this amount during the times the sensors 
are alternately heated.  After the heating stops, the reported RH comes from the sensor 
reading the higher value.  There is no way of knowing if this is the correct value.

• Surface dew point temperature(dp)
• Relative humidity scaled, by total column amount from MWR(rh)

SGP/SONDE/C1 - Reprocess: Incorrect surface temperature and RH

Because of a system problem these two soundings (20070703:1729 and 20070703:2331) have 
incorrect surface values for temperature and RH.

Sounding  BadTemp   BadRH    GoodTemp   GoodRH
17:29      22.60    22.61      27.61     66.97
23:31      22.59     0.00      29.17     64.31

The system has been fixed.

• Surface dew point temperature(dp)
• Dry-Bulb Temperature(tdry)
• Relative humidity scaled, by total column amount from MWR(rh)

SGP/SONDE/C1 - Reprocess: Bad surface RH

It appears that there was some sort of problem with the RH sensor heating cycle regulator 
on this radiosonde.  The surface RH value (66.6% RH) is incorrect and should be 78.7% RH. 
 When I looked at the raw data to try to understand the problem, I noted that the RH 
value in the non-heated sensor did not fully recover to ambient before the next sensor 
heating began.  The problem seemed to go away after launch, but it is hard to be 100% sure.

• Surface dew point temperature(dp)
• Relative humidity scaled, by total column amount from MWR(rh)