Method: 

SHEBA Radiosonde (GLAS) temperatures are interpolated to the corresponding Path-P temperature levels and daily averages are computed.  Path-P temperatures are spatial averages of all retrieval footprints of an an overpass whose centers are within a radius of 50 km from the SHEBA camp. Spatial averages  (varying numbers per day) are then averaged in time to compute daily averages. Results are shown for NOAA-14 only. The analysis was conducted using Level 2 (orbital geophysical data) but minimize geolocation errors but the error statistics should be representative for Level 3 data (Gridded Path-P products). Tables below show the Root Mean Square Error (RMSE), the correlation coefficient (R) and the Mean Error (Radiosonde - TOVS). Coefficients for a linear fit (TTovs=a+b*TRadiosonde) are also shown. 

Atmospheric Temperature
(50 mb)
Variable:   TEMP
Level:  50 mb
RMSE: 2.6
R 0.947
Mean Error (R-T) -1.48
Fit Line (a,b) 5.02,1.072

Scatterplot and time series of SHEBA radiosondes and corresponding Path-P retrievals.
Atmospheric Temperature
(70 mb)
Variable:   TEMP
Level:  70 mb
RMSE: 1.85
R 0.947
Mean Error (R-T) -1.03
Fit Line (a,b) 1.272,1.004

 Scatterplot and time series of SHEBA radiosondes and corresponding Path-P retrievals.
Atmospheric Temperature
(100 mb)
Variable:   TEMP
Level:  100 mb
RMSE: 1.475
R 0.97
Mean Error (R-T) -0.93
Fit Line (a,b) -1.102,0.958

 Scatterplot and time series of SHEBA radiosondes and corresponding Path-P retrievals.
Atmospheric Temperature
(300 mb)
Variable:   TEMP
Level:  300 mb
RMSE: 1.87
R 0.95
Mean Error (R-T) -1.13
Fit Line (a,b) -2.01,0.94

 Scatterplot and time series of SHEBA radiosondes and corresponding Path-P retrievals.
Atmospheric Temperature
(400 mb)
Variable:   TEMP
Level:  400 mb
RMSE: 2.03
R 0.96
Mean Error (R-T) -0.58
Fit Line (a,b) -4.57,0.87

 Scatterplot and time series of SHEBA radiosondes and corresponding Path-P retrievals.
Atmospheric Temperature
(500 mb)
Variable:   TEMP
Level:  500 mb
RMSE: 2.31
R 0.95
Mean Error (R-T) 0.39
Fit Line (a,b) -4.27,0.88

 Scatterplot and time series of SHEBA radiosondes and corresponding Path-P retrievals.
Atmospheric Temperature
(600mb)
Variable:   TEMP
Level:  600 mb
RMSE: 2.53
R 0.95
Mean Error (R-T) 1.08
Fit Line (a,b) -3.320.91

 Scatterplot and time series of SHEBA radiosondes and corresponding Path-P retrievals.
Atmospheric Temperature
(700 mb)
Variable:   TEMP
Level:  700 mb
RMSE: 2.71
R 0.96
Mean Error (R-T) 1.46
Fit Line (a,b) -2.78,0.93

 Scatterplot and time series of SHEBA radiosondes and corresponding Path-P retrievals.
Atmospheric Temperature
(850 mb)
Variable:   TEMP
Level:  850 mb
RMSE: 2.6
R 0.97
Mean Error (R-T) 1.54
Fit Line (a,b) -1.69,0.99

 Scatterplot and time series of SHEBA radiosondes and corresponding Path-P retrievals.
Atmospheric Temperature
(900 mb)
Variable:   TEMP
Level:  900 mb
RMSE: 2.73
R 0.97
Mean Error (R-T) 1.35
Fit Line (a,b) -1.1,1.02

Scatterplot and time series of SHEBA radiosondes and corresponding Path-P retrievals.

NOTES: