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