SGP/AERI/C1 - Metadata errors

The latitude, longitude and altitude of the AERI
were incorrectly entered into the ARM database.  
The correct location of the SGP.C1 AERI is:
   Lat: 36.606N
   Lon: 97.485W
   Alt:    316m

• north latitude for all the input platforms.(lat)
• altitude above sea levelaltunits(alt)
• east longitude for all the input platforms.(lon)

• Sequential data channel number. See channel_explanation global attribute.(channel)
• altitude above sea levelaltunits(alt)
• east longitude for all the input platforms.(lon)

• east longitude for all the input platforms.(lon)
• altitude above sea levelaltunits(alt)
• north latitude for all the input platforms.(lat)

• altitude above sea levelaltunits(alt)
• north latitude for all the input platforms.(lat)
• east longitude for all the input platforms.(lon)

• north latitude for all the input platforms.(lat)
• east longitude for all the input platforms.(lon)
• altitude above sea levelaltunits(alt)

• north latitude for all the input platforms.(lat)
• altitude above sea levelaltunits(alt)
• east longitude for all the input platforms.(lon)

• east longitude for all the input platforms.(lon)
• altitude above sea levelaltunits(alt)
• north latitude for all the input platforms.(lat)

• altitude above sea levelaltunits(alt)
• north latitude for all the input platforms.(lat)
• east longitude for all the input platforms.(lon)

• east longitude for all the input platforms.(lon)
• altitude above sea levelaltunits(alt)
• north latitude for all the input platforms.(lat)

• altitude above sea levelaltunits(alt)
• north latitude for all the input platforms.(lat)
• east longitude for all the input platforms.(lon)

SGP/AERI/B1 - Increased radiative uncertainty during hot summer afternoons

The ambient temperature of the AERI enclosures at the boundary facilities
often exceeded 308 K during hot summer afternoons.  This threshold marked
the maximum end of the "acceptable" range of temperatures that the 
ambient blackbody should maintain.  The issue is that if the hot 
blackbody and ambient blackbody temperatures are too close together, then 
the radiative calibration becomes more uncertain.  It should be noted 
that the hot blackbody's temperature is maintained at roughly 333 K.  

Using the calibration equation, an uncertainty analysis was performed
to see how much "additional" uncertainty resulted in the AERI
observations when the ambient temperature was between 308-315 K (315 K
was the maximum temperature that the ambient blackbody reached during
the summer).  The analysis compared the radiative uncertainties from the
Hillsboro (B1) AERI (chosen at random) with the AERI-01 at the SGP/CF
over a 5-year period.  Plot1 (below) shows the time-series of ambient
blackbody temperatures for the two instruments, along with histograms to
show the distribution of the temperatures.  The boundary facility
instrument did suffer from higher temperatures in the summer
time periods.  Plot2 (bleow) shows the relative radiative uncertainty
for each instrument.  The CF instrument has a maximum radiative
uncertainty of around 0.18% during the summer, while the BF instrument's
maximum radiative uncertainty is about 0.25%.  This plot demonstrates
that the radiative uncertainty is significantly larger for the BF
instrument in the summer relative to the CF instrument.  However, the
absolute radiative accuracy for the AERI is specified to be better than
1% of the ambient radiance, and both the CF and the BF AERIs are well
within this uncertainty.  

In short, there is significantly higher radiative uncertainty in the
BF AERIs during the hot summer afternoons, but the uncertainty is well
within the specified accuracy of the instrument.

plot1:  aeri_abb_temp.lamont_hillsboro.png 

plot2:  aeri_relative_error.lamont_hillsboro.png 

• Downwelling radiance interpolated to standard wavenumber scale(mean_rad)

• Downwelling radiance interpolated to standard wavenumber scale(mean_rad)

SGP/AERI/B4 - Increased radiative uncertainty during hot summer afternoons

The ambient temperature of the AERI enclosures at the boundary facilities
often exceeded 308 K during hot summer afternoons.  This threshold marked
the maximum end of the "acceptable" range of temperatures that the 
ambient blackbody should maintain.  The issue is that if the hot 
blackbody and ambient blackbody temperatures are too close together, then 
the radiative calibration becomes more uncertain.  It should be noted 
that the hot blackbody's temperature is maintained at roughly 333 K.  

Using the calibration equation, an uncertainty analysis was performed
to see how much "additional" uncertainty resulted in the AERI
observations when the ambient temperature was between 308-315 K (315 K
was the maximum temperature that the ambient blackbody reached during
the summer).  The analysis compared the radiative uncertainties from the
Hillsboro (B1) AERI (chosen at random) with the AERI-01 at the SGP/CF
over a 5-year period.  Plot1 (below) shows the time-series of ambient
blackbody temperatures for the two instruments, along with histograms to
show the distribution of the temperatures.  The boundary facility
instrument did suffer from higher temperatures in the summer
time periods.  Plot2 (bleow) shows the relative radiative uncertainty
for each instrument.  The CF instrument has a maximum radiative
uncertainty of around 0.18% during the summer, while the BF instrument's
maximum radiative uncertainty is about 0.25%.  This plot demonstrates
that the radiative uncertainty is significantly larger for the BF
instrument in the summer relative to the CF instrument.  However, the
absolute radiative accuracy for the AERI is specified to be better than
1% of the ambient radiance, and both the CF and the BF AERIs are well
within this uncertainty.  

In short, there is significantly higher radiative uncertainty in the
BF AERIs during the hot summer afternoons, but the uncertainty is well
within the specified accuracy of the instrument.

plot1:  aeri_abb_temp.lamont_hillsboro.png 

plot2:  aeri_relative_error.lamont_hillsboro.png 

• Downwelling radiance interpolated to standard wavenumber scale(mean_rad)

• Downwelling radiance interpolated to standard wavenumber scale(mean_rad)

SGP/AERI/B5 - Increased radiative uncertainty during hot summer afternoons

The ambient temperature of the AERI enclosures at the boundary facilities
often exceeded 308 K during hot summer afternoons.  This threshold marked
the maximum end of the "acceptable" range of temperatures that the 
ambient blackbody should maintain.  The issue is that if the hot 
blackbody and ambient blackbody temperatures are too close together, then 
the radiative calibration becomes more uncertain.  It should be noted 
that the hot blackbody's temperature is maintained at roughly 333 K.  

Using the calibration equation, an uncertainty analysis was performed
to see how much "additional" uncertainty resulted in the AERI
observations when the ambient temperature was between 308-315 K (315 K
was the maximum temperature that the ambient blackbody reached during
the summer).  The analysis compared the radiative uncertainties from the
Hillsboro (B1) AERI (chosen at random) with the AERI-01 at the SGP/CF
over a 5-year period.  Plot1 (below) shows the time-series of ambient
blackbody temperatures for the two instruments, along with histograms to
show the distribution of the temperatures.  The boundary facility
instrument did suffer from higher temperatures in the summer
time periods.  Plot2 (bleow) shows the relative radiative uncertainty
for each instrument.  The CF instrument has a maximum radiative
uncertainty of around 0.18% during the summer, while the BF instrument's
maximum radiative uncertainty is about 0.25%.  This plot demonstrates
that the radiative uncertainty is significantly larger for the BF
instrument in the summer relative to the CF instrument.  However, the
absolute radiative accuracy for the AERI is specified to be better than
1% of the ambient radiance, and both the CF and the BF AERIs are well
within this uncertainty.  

In short, there is significantly higher radiative uncertainty in the
BF AERIs during the hot summer afternoons, but the uncertainty is well
within the specified accuracy of the instrument.

plot1:  aeri_abb_temp.lamont_hillsboro.png 

plot2:  aeri_relative_error.lamont_hillsboro.png 

• Downwelling radiance interpolated to standard wavenumber scale(mean_rad)

• Downwelling radiance interpolated to standard wavenumber scale(mean_rad)

SGP/AERI/B6 - Increased radiative uncertainty during hot summer afternoons

The ambient temperature of the AERI enclosures at the boundary facilities
often exceeded 308 K during hot summer afternoons.  This threshold marked
the maximum end of the "acceptable" range of temperatures that the 
ambient blackbody should maintain.  The issue is that if the hot 
blackbody and ambient blackbody temperatures are too close together, then 
the radiative calibration becomes more uncertain.  It should be noted 
that the hot blackbody's temperature is maintained at roughly 333 K.  

Using the calibration equation, an uncertainty analysis was performed
to see how much "additional" uncertainty resulted in the AERI
observations when the ambient temperature was between 308-315 K (315 K
was the maximum temperature that the ambient blackbody reached during
the summer).  The analysis compared the radiative uncertainties from the
Hillsboro (B1) AERI (chosen at random) with the AERI-01 at the SGP/CF
over a 5-year period.  Plot1 (below) shows the time-series of ambient
blackbody temperatures for the two instruments, along with histograms to
show the distribution of the temperatures.  The boundary facility
instrument did suffer from higher temperatures in the summer
time periods.  Plot2 (bleow) shows the relative radiative uncertainty
for each instrument.  The CF instrument has a maximum radiative
uncertainty of around 0.18% during the summer, while the BF instrument's
maximum radiative uncertainty is about 0.25%.  This plot demonstrates
that the radiative uncertainty is significantly larger for the BF
instrument in the summer relative to the CF instrument.  However, the
absolute radiative accuracy for the AERI is specified to be better than
1% of the ambient radiance, and both the CF and the BF AERIs are well
within this uncertainty.  

In short, there is significantly higher radiative uncertainty in the
BF AERIs during the hot summer afternoons, but the uncertainty is well
within the specified accuracy of the instrument.

plot1:  aeri_abb_temp.lamont_hillsboro.png 

plot2:  aeri_relative_error.lamont_hillsboro.png 

• Downwelling radiance interpolated to standard wavenumber scale(mean_rad)

• Downwelling radiance interpolated to standard wavenumber scale(mean_rad)

SGP/AERI/C1 - Data Reprocessed to correct laser wavenumber

SGP.C1 AERI data from 20000302-20020510 have been reprocessed
to correct for the spectral calibration; i.e., to correct the
laser wavenumber.  These data are now available from the ARM
Archive.

Data users who retrieved the previous version of this data from 
the archive should consider the following graphic to gauge the
impact the correction might have on their analyses.


vlaser_correction_example.png  

Note: only the ch1 and ch2 data were reprocessed; the summary
data have not been recomputed.  The summary data typically
are 5 to 25 cm-1 spectral averages of the ch1 and ch2 data,
and the effect of the spectral calibration on these averages
should be negligible.

• Downwelling radiance interpolated to standard wavenumber scale(mean_rad)

• Downwelling radiance interpolated to standard wavenumber scale(mean_rad)