SGP/SMOS/E13 - 6-month Calibration Checks

During the time periods specified, the SMOS.E13 tower was lowered for 6-month Calibration 
Checks.  During these times wind data are incorrect and temperature and humidity data may 
be incorrect.

Note, exact times when tower was down or maintenance was being performed is sometimes 
unknown.  Users should use the remaining data from these days with caution.

Calibration results are available from the OMIS database at 
    
http://www.ops.sgp.arm.gov:591/smos6cal/default.htm 
To view all 6-month calibration reports leave the date time entry blank.

• maximum wind speed (gusts)(max_wspd)
• Time of Maximum Vapor Pressure(time_max_vap_pres)
• Time of Maximum Barometric Pressure(time_max_bar_pres)
• Minimum of Wind speed(min_wspd)
• Time of Minimum Vapor Pressure(time_min_vap_pres)
• Maximum Relative Humidity(max_rh)
• Minimum Temperature(min_temp)
• Time of Minimum Temperature(time_min_temp)
• Time of Minimum Relative Humidity(time_min_rh)
• Minimum Barometric Pressure(min_bar_pres)
• Maximum Vapor Pressure(max_vap_pres)
• Time of Maximum Temperature(time_max_temp)
• Time of Maximum Relative Humidity(time_max_rh)
• Time of Minimum Wind Speed(time_min_wspd)
• Minimum Relative Humidity(min_rh)
• Time of Maximum Wind Speed(time_max_wspd)
• Maximum Temperature(max_temp)
• Minimum Vapor Pressure(min_vap_pres)
• Maximum Barometric Pressure(max_bar_pres)
• Time of Minimum Barometric Pressure(time_min_bar_pres)

• Wind Speed (vector averaged)(wspd_va)
• Standard Deviation of Barometric Pressure(sd_bar_pres)
• Vapor Pressure (kiloPascals)(vap_pres)
• Relative humidity inside the instrument enclosure(rh)
• Standard Deviation of Wind Speed(sd_wspd)
• Mean Wind Speed(wspd)
• Unit Vector Wind Direction(wdir)
• Standard Deviation of Air Temperature(sd_temp)
• Standard Deviation of Relative Humidity(sd_rh)
• Standard Deviation of Vapor Pressure(sd_vap_pres)
• barometric pressure(bar_pres)
• Standard Deviation of wind direction(sd_deg)
• Beam 0 Temperature(temp)

• barometric pressure(bar_pres)
• Relative humidity inside the instrument enclosure(rh)
• Standard Deviation of wind direction(sd_deg)
• Wind Speed (vector averaged)(wspd_va)
• Unit Vector Wind Direction(wdir)
• Mean Wind Speed(wspd)
• Vapor Pressure (kiloPascals)(vap_pres)
• Beam 0 Temperature(temp)

SGP/SMOS/E13 - Wind Data Suspect

Wind speed and direction data suspect during time period due to icing.

• maximum wind speed (gusts)(max_wspd)
• Time of Minimum Wind Speed(time_min_wspd)
• Minimum of Wind speed(min_wspd)
• Time of Maximum Wind Speed(time_max_wspd)

• Unit Vector Wind Direction(wdir)
• Wind Speed (vector averaged)(wspd_va)
• Standard Deviation of Wind Speed(sd_wspd)
• Standard Deviation of wind direction(sd_deg)
• Mean Wind Speed(wspd)

• Mean Wind Speed(wspd)
• Standard Deviation of wind direction(sd_deg)
• Wind Speed (vector averaged)(wspd_va)
• Unit Vector Wind Direction(wdir)

SGP/SMOS/E13 - T/RH sensor failure

The T/RH sensor began to fail at high RH% values.  Since this site has an aspirated 
radiation shield, values in excess of the 104% manufacturer limit are not expected to occur due 
to rain or condensation.

• Time of Maximum Relative Humidity(time_max_rh)
• Time of Maximum Vapor Pressure(time_max_vap_pres)
• Minimum Relative Humidity(min_rh)
• Time of Minimum Vapor Pressure(time_min_vap_pres)
• Maximum Relative Humidity(max_rh)
• Time of Minimum Relative Humidity(time_min_rh)
• Maximum Vapor Pressure(max_vap_pres)
• Minimum Vapor Pressure(min_vap_pres)

• Standard Deviation of Relative Humidity(sd_rh)
• Standard Deviation of Vapor Pressure(sd_vap_pres)
• Vapor Pressure (kiloPascals)(vap_pres)
• Relative humidity inside the instrument enclosure(rh)

• Relative humidity inside the instrument enclosure(rh)
• Vapor Pressure (kiloPascals)(vap_pres)

SGP/MWR/C1 - REPROCESS - Revised Retrieval Coefficients

IN THE BEGINNING (June 1992), the retrieval coefficients used to derive the precipitable 
water vapor (PWV) and liquid water path (LWP) from the MWR brightness temperatures were 
based on the Liebe and Layton (1987) water vapor and oxygen absorption model and the Grant 
(1957) liquid water absorption model.  

Following the SHEBA experience, revised retrievals based on the more recent Rosenkranz 
(1998) water vapor and oxygen absorption models and the Liebe (1991) liquid waer absorption 
model were developed.  The Rosenkranz water vapor absorption model resulted a 2 percent 
increase in PWV relative to the earlier Liebe and Layton model.  The Liebe liquid water 
absorption model decreased the LWP by 10% relative to the Grant model.  However, the 
increased oxygen absorption caused a 0.02-0.03 mm (20-30 g/m2) reduction in LWP, which was 
particularly significant for low LWP conditions (i.e. thin clouds encountered at SHEBA).

Recently, it has been shown (Liljegren, Boukabara, Cady-Pereira, and Clough, TGARS v. 43, 
pp 1102-1108, 2005) that the half-width of the 22 GHz water vapor line from the HITRAN 
compilation, which is 5 percent smaller than the Liebe and Dillon (1969) half-width used in 
Rosenkranz (1998), provided a better fit to the microwave brightness temperature 
measurements at 5 frequencies in the range 22-30 GHz, and yielded more accurate retrievals.  
Accordingly, revised MWR retrieval coefficients have been developed using MONORTM, which 
utilizes the HITRAN compilation for its spectroscopic parameters.  These new retrievals 
provide 3 percent less PWV and 2.6 percent greater LWP than the previous retrievals based on 
Rosenkranz (1998).

Although the MWR data will be reprocessed to apply the new monortm-based retrievals, for 
most purposes it will be sufficient to correct the data using the following factors:

PWV_MONORTM = 0.9695 * PWV_ROSENKRANZ
LWP_MONORTM = 1.026  * LWP_ROSENKRANZ

The Rosenkranz-based retrieval coefficients became active as follows (BCR 456):
SGP/C1 (Lamont)     4/16/2002, 2000
SGP/B1 (Hillsboro)  4/12/2002, 1600
SGP/B4 (Vici)       4/15/2002, 2300
SGP/B5 (Morris)     4/15/2002, 2300
SGP/B6 (Purcell)    4/16/2002, 2200
SGP/E14(Lamont)     4/16/2002, 0000
NSA/C1 (Barrow)     4/25/2002, 1900 
NSA/C2 (Atqasuk)    4/18/2002, 1700
TWP/C1 (Manus)      5/04/2002, 0200
TWP/C2 (Nauru)      4/27/2002, 0600
TWP/C3 (Darwin)     inception

The MONORTM-based retrieval coefficients became active as follows (BCR 984):

SGP/C1 (Lamont)     6/28/2005, 2300
SGP/B1 (Hillsboro)  6/24/2005, 2100
SGP/B4 (Vici)       6/24/2005, 2100
SGP/B5 (Morris)     6/24/2005, 2100
SGP/B6 (Purcell)    6/24/2005, 1942
SGP/E14(Lamont)     6/28/2005, 2300
NSA/C1 (Barrow)     6/29/2005, 0000 
NSA/C2 (Atqasuk)    6/29/2005, 0000
TWP/C1 (Manus)      6/30/2005, 2100
TWP/C2 (Nauru)      6/30/2005, 2100
TWP/C3 (Darwin)     6/30/2005, 2100
PYE/M1 (Pt. Reyes)  4/08/2005, 1900**

** At Pt. Reyes, the original retrieval coefficients implemented in March 2005 were based 
on a version of the Rosenkranz model that had been modified to use the HITRAN half-width 
at 22 GHz and to be consistent with the water vapor continuum in MONORTM.  These 
retrievals yield nearly identical results to the MONORTM retrievals.  Therefore the Pt. Reyes 
data prior to 4/08/2005 may not require reprocessing.

• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)

• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)

• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)

• Averaged total liquid water along LOS path(liq)
• MWR column precipitable water vapor(vap)

• Ensemble average for MWR vapor in window centered about balloon release(mean_vap_mwr)
• Ensemble average for MWR liquid in window centered about balloon release(mean_liq_mwr)

• Averaged total liquid water along LOS path(liq)
• MWR column precipitable water vapor(vap)

SGP/MWR/C1 - Instrument noise problem

Various variables including the mixer temperatures were very noisy. After several attempts 
to fix the problem, the instrument was taken off line and returned to the manufacturer 
for repair.

• 31.4 GHz blac2body+noise injection signal(bbn31)
• 31.4 GHz blackbody(bb31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• (tknd)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Blackbody kinetic temperature(tkbb)
• 23.8 GHz Blackbody signal(bb23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Ambient temperature(tkair)
• Mixer kinetic (physical) temperature(tkxc)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• 31.4 GHz sky signal(tipsky31)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky signal(tipsky23)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz sky brightness temperature derived from tip curve(tbsky31tip)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbsky23tip)
• 23.8 GHz goodness-of-fit coefficient(r23)

• Flag indicating where the initial surface water measurements are from: 0-> SMOS,
  1-> AERI(water_flag)
• Fraction of data in averaging interval with water on Teflon window(water_flag_fraction)
• 23.8 GHz sky brightness temperature(23tbsky)
• Standard deviation about the mean for the IR brightness temperature(ir_temp_sdev)
• Number of data points averaged out of 15(number_obs_averaged)
• Standard deviation about the mean for the 31.4 GHz sky brightness temperature(tbsky31_sdev)
• Standard deviation about the mean for the total water vapor amount(vap_sdev)
• Averaged total liquid water along LOS path(liq)
• IR Brightness Temperature(ir_temp)
• Probability of level change in ratio of averaged brightness temps(prob_level_change)
• Standard deviation about the mean for the 23.8 GHz sky brightness temperature(tbsky23_sdev)
• Probability of slope change in ratio of averaged brightness temps(prob_slope_change)
• Probability of outlier in ratio of averaged brightness temps(prob_outlier)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• 31.4 GHz sky brightness temperature(31tbsky)
• Standard deviation about the mean for the total liquid water amount(liq_sdev)
• MWR column precipitable water vapor(vap)

• 31.4 GHz sky signal(sky31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky signal(sky23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Averaged total liquid water along LOS path(liq)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz blackbody(bb31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Blackbody kinetic temperature(tkbb)
• Sky Infra-Red Temperature(sky_ir_temp)
• MWR column precipitable water vapor(vap)
• Ambient temperature(tkair)
• 23.8 GHz Blackbody signal(bb23)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Mixer kinetic (physical) temperature(tkxc)
• (tknd)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Temperature correction coefficient at 23.8 GHz(tc23)

• Sky brightness temperature at 23.8 GHz(tbsky23)
• Fraction of data in averaging interval flagged by Dynamic Linear Model as poten(dlm_flag_fraction)
• Standard deviation about the mean for the total water vapor amount(vap_sdev)
• 23.8 GHz sky brightness temperature(23tbsky)
• Standard deviation about the mean for the IR brightness temperature(ir_temp_sdev)
• IR Brightness Temperature(ir_temp)
• MWR column precipitable water vapor(vap)
• Number of contiguous periods in averaging interval flagged by Dynamic Linear Mo(dlm_flag_periods)
• Standard deviation about the mean for the 23.8 GHz sky brightness temperature(tbsky23_sdev)
• Standard deviation about the mean for the total liquid water amount(liq_sdev)
• Number of contiguous periods in averaging interval with water on Teflon window(water_flag_periods)
• Standard deviation about the mean for the 31.4 GHz sky brightness temperature(tbsky31_sdev)
• Fraction of data in averaging interval with water on Teflon window(water_flag_fraction)
• 31.4 GHz sky brightness temperature(31tbsky)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 31.4 GHz(tbsky31)

SGP/MWR/C1 - Instrument offline

Instrument was taken offline and returned to manufacturer for repair.  Data are missing 
and unrecoverable.

• 31.4 GHz blackbody(bb31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Actual elevation angle(actel)
• Blackbody kinetic temperature(tkbb)
• Ambient temperature(tkair)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 31.4 GHz sky signal(tipsky31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky signal(tipsky23)
• Time offset of tweaks from base_time(time_offset)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• (tknd)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 23.8 GHz Blackbody signal(bb23)
• lat(lat)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Mixer kinetic (physical) temperature(tkxc)
• Dummy altitude for Zeb(alt)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Actual Azimuth(actaz)
• base time(base_time)
• lon(lon)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 31.4 GHz sky brightness temperature derived from tip curve(tbsky31tip)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbsky23tip)
• 23.8 GHz goodness-of-fit coefficient(r23)

• Flag indicating where the initial surface water measurements are from: 0-> SMOS,
  1-> AERI(water_flag)
• Fraction of data in averaging interval with water on Teflon window(water_flag_fraction)
• 23.8 GHz sky brightness temperature(23tbsky)
• Standard deviation about the mean for the 31.4 GHz sky brightness temperature(tbsky31_sdev)
• Standard deviation about the mean for the total water vapor amount(vap_sdev)
• IR Brightness Temperature(ir_temp)
• Standard deviation about the mean for the 23.8 GHz sky brightness temperature(tbsky23_sdev)
• Probability of slope change in ratio of averaged brightness temps(prob_slope_change)
• Number of points included in the ir_temp ensemble(num_obs_irt)
• 31.4 GHz sky brightness temperature(31tbsky)
• Standard deviation about the mean for the total liquid water amount(liq_sdev)
• MWR column precipitable water vapor(vap)
• Dummy altitude for Zeb(alt)
• lat(lat)
• Standard deviation about the mean for the IR brightness temperature(ir_temp_sdev)
• Number of data points averaged out of 15(number_obs_averaged)
• base time(base_time)
• Averaged total liquid water along LOS path(liq)
• Probability of level change in ratio of averaged brightness temps(prob_level_change)
• lon(lon)
• Number of data points averaged for 23tbsky, 31tbsky, vap & liq(num_obs)
• Probability of outlier in ratio of averaged brightness temps(prob_outlier)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Time offset of tweaks from base_time(time_offset)

• 31.4 GHz sky signal(sky31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• lon(lon)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• MWR column precipitable water vapor(vap)
• 23.8 GHz Blackbody signal(bb23)
• Time offset of tweaks from base_time(time_offset)
• (tknd)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Dummy altitude for Zeb(alt)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 23.8 GHz sky signal(sky23)
• Averaged total liquid water along LOS path(liq)
• 31.4 GHz blackbody(bb31)
• Blackbody kinetic temperature(tkbb)
• Sky Infra-Red Temperature(sky_ir_temp)
• Ambient temperature(tkair)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Mixer kinetic (physical) temperature(tkxc)
• base time(base_time)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• lat(lat)

• Sky brightness temperature at 23.8 GHz(tbsky23)
• Fraction of data in averaging interval flagged by Dynamic Linear Model as poten(dlm_flag_fraction)
• 23.8 GHz sky brightness temperature(23tbsky)
• Standard deviation about the mean for the IR brightness temperature(ir_temp_sdev)
• IR Brightness Temperature(ir_temp)
• MWR column precipitable water vapor(vap)
• Time offset of tweaks from base_time(time_offset)
• Number of contiguous periods in averaging interval flagged by Dynamic Linear Mo(dlm_flag_periods)
• lat(lat)
• lon(lon)
• base time(base_time)
• Number of points included in the ir_temp ensemble(num_obs_irt)
• Standard deviation about the mean for the 31.4 GHz sky brightness temperature(tbsky31_sdev)
• Dummy altitude for Zeb(alt)
• Averaged total liquid water along LOS path(liq)
• Standard deviation about the mean for the total water vapor amount(vap_sdev)
• Number of data points averaged for 23tbsky, 31tbsky, vap & liq(num_obs)
• Standard deviation about the mean for the 23.8 GHz sky brightness temperature(tbsky23_sdev)
• Standard deviation about the mean for the total liquid water amount(liq_sdev)
• Number of data points averaged for ir_temp(num_obs_ir)
• Number of contiguous periods in averaging interval with water on Teflon window(water_flag_periods)
• Fraction of data in averaging interval with water on Teflon window(water_flag_fraction)
• 31.4 GHz sky brightness temperature(31tbsky)
• Sky brightness temperature at 31.4 GHz(tbsky31)

SGP/SMOS/E13 - Reprocess: Barometer data a factor of 10 too high.

The program was modified and an incorrect multiplier was used so that the barometer data 
was reported in hPa instead of kPa.

• Minimum Barometric Pressure(min_bar_pres)
• Maximum Barometric Pressure(max_bar_pres)

• barometric pressure(bar_pres)
• Standard Deviation of Barometric Pressure(sd_bar_pres)

• barometric pressure(bar_pres)

SGP/SMOS/E13 -Reprocess:  Wind Speed Values Excessively High

The slope value to convert the rotation of the propeller from engineering units to 
meters/second was incorrectly given as .098 when it should have been .0049.  Conversion was 
converting hertz to meters/second when it should have been converting rpm's to meters/second.

• maximum wind speed (gusts)(max_wspd)
• Minimum of Wind speed(min_wspd)

• Mean Wind Speed(wspd)

SGP/SMOS/E13 - RH sensor failure

The T/RH sensor relative humidity data is suspect during this time.  Values from this 
sensor failed the 6-month check and subsequent bi-weekly checks.  The RH values were lower by 
larger than the manufacturer suggested uncertainty of 3%.

• Time of Maximum Relative Humidity(time_max_rh)
• Time of Maximum Vapor Pressure(time_max_vap_pres)
• Minimum Relative Humidity(min_rh)
• Time of Minimum Vapor Pressure(time_min_vap_pres)
• Maximum Relative Humidity(max_rh)
• Time of Minimum Relative Humidity(time_min_rh)
• Maximum Vapor Pressure(max_vap_pres)
• Minimum Vapor Pressure(min_vap_pres)

• Standard Deviation of Relative Humidity(sd_rh)
• Standard Deviation of Vapor Pressure(sd_vap_pres)
• Vapor Pressure (kiloPascals)(vap_pres)
• Relative humidity inside the instrument enclosure(rh)

• Relative humidity inside the instrument enclosure(rh)
• Vapor Pressure (kiloPascals)(vap_pres)