A Comparison of FNOC and the MRF in the Tropics

Glenn.White@noaa.gov

During the last few years the NCEP global model has trailed other centers in standardized skill scores in the tropics, particularly in root mean square wind vector error at 850 hPa. During this hurricane season (2001) the NCEP global model outperformed other centers in forecasting the tracks of hurricanes, but still trailed them in RMS vector error. This page presents some preliminary results of an intercomparison of tropical analyses and 3-day forecasts by the NCEP global medium-range forecast (MRF) model and the U.S. Navy global model (FNOC).

Root-mean-square error 20S-20N

Zonal wind

850 hPa	300 hPa	200 hPa
Time series of rms errors and rms differences in analyses and forecasts	Time series of rms errors and rms differences in analyses and forecasts	Time series of rms errors and rms differences in analyses and forecasts

Vertical cross-sections

Zonal Wind	Meridional Wind
RMS error FNOC	RMS error FNOC
RMS error NCEP	RMS error NCEP
Difference in RMS error FNOC-NCEP	Difference in RMS error FNOC-NCEP
RMS difference in analyses
RMS difference in forecasts

Root-mean-square value of zonal wind

850 mb	300 mb	200 mb
Analyses and 3 day fcsts time series	Analyses and 3 day fcsts time series	Analyses and 3 day fcsts time series

Vertical cross-sections

FNOC	NCEP	FNOC-NCEP
Analyses	Analyses	Analyses
3 day fcsts		3 day fcsts
3 dy fcsts-analyses	3 dy fcsts-analyses

Time-means

Zonal Wind

Zonal mean	Equator
Analyses	Analyses
3 day forecasts	3 day forecasts
Differences in analyses, 3 dy fcsts	Differences in analyses, 3 dy fcsts
3 day fcsts minus analyses	3 day fcsts minus analyses

Meridional Wind

Zonal mean	Equator
Analyses	Analyses
3 day forecasts	3 day forecasts
Differences in analyses, 3 dy fcsts	Differences in analyses, 3 dy fcsts
3 day fcsts minus analyses	3 day fcsts minus analyses

Transient Eddies

20S-20N

Zonal wind

Meridional wind

Zonal Mean

Zonal Wind

FNOC	NCEP	FNOC-NCEP
Analyses	Analyses	Analyses
3 day forecasts	3 day forecasts	3 day forecasts
3 day fcsts minus analyses	3 day fcsts minus analyses

Meridional Wind

FNOC	NCEP	FNOC-NCEP
Analyses	Analyses	Analyses
3 day forecasts	3 day forecasts	3 day forecasts
3 day fcsts minus analyses	3 day fcsts minus analyses