GOES Sounder TPW evaluation with GOES-R algorithm
CIMSS sounding team (Tim Schmit, Jun Li, Zhenglong Li, Yong-Keun Lee etc.)
01 June 2012
Validation data
• GOES-13 Sounder• Microwave radiometer (MWR) total
precipitable water measurements at ARM Cart Site
• Radiosondes over CONUS
Two algorithms are tested
• Same inputs (channels, GFS)• GOES Sounder Li algorithm – Regression as first guess– Surface temperature and moisture observations
are used in the retrieval• GOES-R LAP algorithm – Regression as first guess– No surface temperature and moisture observations
used in the retrieval
TPW (mm)
Mean RMSE STD
GFS 0.37 1.98 1.95
Li ALG 0.47 1.90 1.85
GOES-R ALG
0.10 1.66 1.66
GFS TPW GOES Li ALG TPW
GOES-R ALG TPW
GOES-13 Sounder TPW comparisons with MWR TPW over ARM Cart Site (April 2010 – March 2011)
GOES-13 Sounder TPW comparisons with RAOBs at 57 locations over CONUS
• Time coverage : 2011.02.01 – 2012.01.31• Temporal collocation criteria: +/- 30 minutes
from RAOB measurement• Spatial collocation criteria: 0.2 degree from
RAOB measurement
57 RAOB locations over CONUS
TPW Scatterplot with RAOB for one year over CONUSWith quality flags
TPW (mm)
Mean RMSE STD
GFS -0.03 3.27 3.27
Li ALG -0.21 3.29 3.28
GOES-R ALG
-0.12 3.06 3.06
Summary
• Validation with MWR TPW and RAOBs show that GOES Sounder with GOES-R LAP algorithm provides better accuracy and precision than the Li-algorithm
• GOES-R algorithm has much smaller bias in summer than Li-algorithm compared with RAOBs (not shown)
• Recommend to use GOES-R algorithm for GOES Sounder operational production generation– Surface T/q observations should be added