Comparison between the ECMWF T511 Nature Run against climatology

Comparison between the ECMWF T511 Nature Run against climatology.

20050601-20060531, exp=eskb, cycle=31r1

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A large number of standard diagnostic plots have been produced with the 'climplot' software (Adrian Tompkins), at ECMWF. Climplot compares monthly (and longer) averages of model fields against multi-year accumulations of available validation data sets. The length of each validation data set varies, and is indicated in the label of the second panel of each plot. The validation has been done for each of the 12 individual months, for three-monthly, and for yearly averages. The Nature Run integration started 20060501 and the first month has been disregarded as a 'warm-up' period.

The resulting plots are stored in directories:

Yearly/200506

Quarterly/200506 Quarterly/200509 Quarterly/200512 Quarterly/200603

Monthly/200506 Monthly/200507 Monthly/200508 Monthly/200509 Monthly/200510

Monthly/200511 Monthly/200512 Monthly/200601 Monthly/200602 Monthly/200603

Monthly/200604 Monthly/200605

In some cases validation data sets were available for the actual period of the Nature Run. The NR has also been compared to these data; the resulting plots are in the same directories as the validations against climatological data sets, with different file names. See below.

There is a similar set of plots in each directory. The following comments are general, but the given file names refer to the yearly averages. In the description below known model biases are highlighted that we are aware of, and will receive attention in upcoming physics revisions. Known deficiencies in retrieval products are also mentioned. For a thorough discussion of model systematic errors see ECMWF TechMemo 452 Tompkins et al. (2004) and Jung et al. (2005) TechMemo 471.

**DESCRIPTION, VALIDATION AGAINST CLIMATOLOGY**

**Winds at 10m level against QuikSCAT vector winds and SSMI wind speeds.

clim_eskb_climatol_10wind_quikscat_nens1_200506_nmon12.ps

clim_eskb_climatol_10wind_ssmi_nens1_200506_nmon12.ps

- Quikscat does not provide winds in rainy areas

- Shows known bias in the W Pacific. Model winds are too low in

deep convective areas.

**Ice water path

clim_eskb_climatol_iwp_noaa_nens1_200506_nmon12.ps

- the NOAA product is only for thin cirrus clouds, with a narrow

optical septh range, which makes the comparison unreliable

**Top of the atmosphere long-wave radiation

clim_eskb_climatol_lw_ceres_nens1_200506_nmon12.ps

clim_eskb_climatol_lw_ceres_np_nens1_200506_nmon12.ps

clim_eskb_climatol_lw_ceres_sp_nens1_200506_nmon12.ps

clim_eskb_climatol_lw_noaa_nens1_200506_nmon12.ps --- DEAD file ---

- Shows lack of deep convection over the tropical land masses. This agrees with evidence from other data sets. Also agrees with earlier comparisons with ERBE data. A long-standing bias that has improved with recent model changes, but require further attention.

**Top of the atmosphere long-wave cloud forcing??

clim_eskb_climatol_lwcf_ceres_nens1_200506_nmon12.ps

clim_eskb_climatol_lwcf_ceres_np_nens1_200506_nmon12.ps

clim_eskb_climatol_lwcf_ceres_sp_nens1_200506_nmon12.ps

- No product where continually cloudy.

- Proves that the IR biases in net radiation are due to clouds.

**Total precipitation, against GPCP, SSMI, TRMM and XieArkin

clim_eskb_climatol_precip_gpcp_nens1_200506_nmon12.ps

clim_eskb_climatol_precip_gpcp_np_nens1_200506_nmon12.ps

clim_eskb_climatol_precip_gpcp_sp_nens1_200506_nmon12.ps

clim_eskb_climatol_precip_ssmi_nens1_200506_nmon12.ps

clim_eskb_climatol_precip_trmm_nasda_3b43_nens1_200506_nmon12.ps

clim_eskb_climatol_precip_trmm_rss_nens1_200506_nmon12.ps

clim_eskb_climatol_precip_xiearkin_nens1_200506_nmon12.ps

- These comparisons confirm the lack of rainfall over the tropical land masses.

- We have an overestimation of precip over the high-SST regions in the tropics.

- There is a tendency for deep convection to become locked in with the highest SSTs, which in the east Pacific results in a narrow ITCZ

- The TRMM NASDA-3b43 algorithm is presumed to be the most accurate of the two TRMM retrieval products.

**Surface heat fluxes

clim_eskb_climatol_sflux_ds_SLH_nens1_200506_nmon12.ps - latent

clim_eskb_climatol_sflux_ds_SNET_nens1_200506_nmon12.ps - net

clim_eskb_climatol_sflux_ds_SSH_nens1_200506_nmon12.ps - sensible

clim_eskb_climatol_sflux_ds_SSR_nens1_200506_nmon12.ps - solar

clim_eskb_climatol_sflux_ds_STR_nens1_200506_nmon12.ps - infrared

- Surface fluxes observations are indirect measurements and are less reliable on a month-by-month basis. Ask Anton Beljaars.

**Top of the atmosphere short-wave radiation

clim_eskb_climatol_sw_ceres_nens1_200506_nmon12.ps

clim_eskb_climatol_sw_ceres_np_nens1_200506_nmon12.ps

clim_eskb_climatol_sw_ceres_sp_nens1_200506_nmon12.ps

- This is now dramatically improved compred to earlier cycle of the model, and compared to ERA-40 (for example).

- Still small problem in the stratocumulus regions close to the coasts, despite of recent improvements.

**Top of the atmosphere short-wave cloud forcing

clim_eskb_climatol_swcf_ceres_nens1_200506_nmon12.ps

clim_eskb_climatol_swcf_ceres_np_nens1_200506_nmon12.ps

clim_eskb_climatol_swcf_ceres_sp_nens1_200506_nmon12.ps

- See above, for sw-radiation.

**Total cloud cover

clim_eskb_climatol_tcc_isccp_tcc_nens1_200506_nmon12.ps

clim_eskb_climatol_tcc_modis_np_tcc_nens1_200506_nmon12.ps

clim_eskb_climatol_tcc_modis_sp_tcc_nens1_200506_nmon12.ps

clim_eskb_climatol_tcc_modis_tcc_nens1_200506_nmon12.ps

- This has improved greatly in recent cycles of the model. In particular, the stratocumulus regions have improved.

- The apparent underestimation relative to ISCCP over the Sahara is because this product is

thought to overestimate cloud cover there. MODIS shows better agreement with the model over the deserts.

- The MODIS product over sea ice is unreliable

**Liquid water path

clim_eskb_climatol_tclw_ssmi_nens1_200506_nmon12.ps

clim_eskb_climatol_tclw_trmm_rss_nens1_200506_nmon12.ps

- This is now much better in the trade cumulus regions, than in previous model cycles.

- Clear underestimation in western Pacific

**Total-column water vapour

clim_eskb_climatol_tcwv_ssmi_nens1_200506_nmon12.ps

clim_eskb_climatol_tcwv_trmm_rss_nens1_200506_nmon12.ps

- Remarkable agreement in the extra-tropics. Underestimation in the ITCZ.

**DESCRIPTION, VALIDATION AGAINST JUNE05-MAY06 DATA SETS**

clim_eskb_iwp_noaa_nens1_200506_nmon12.ps

clim_eskb_precip_trmm_nasda_3b43_nens1_200506_nmon12.ps

**Surface sensible heat flux

clim_eskb_sflux_ds_SLH_nens1_200506_nmon12.ps

clim_eskb_sflux_ds_SNET_nens1_200506_nmon12.ps

clim_eskb_sflux_ds_SSH_nens1_200506_nmon12.ps

clim_eskb_sflux_ds_SSR_nens1_200506_nmon12.ps

clim_eskb_sflux_ds_STR_nens1_200506_nmon12.ps

**Total cloud cover

clim_eskb_tcc_isccp_tcc_nens1_200506_nmon12.ps

clim_eskb_tcc_modis_np_tcc_nens1_200506_nmon12.ps

clim_eskb_tcc_modis_sp_tcc_nens1_200506_nmon12.ps

clim_eskb_tcc_modis_tcc_nens1_200506_nmon12.ps