EWGLAM Oct 2003 1

Some recent developments in the ECMWF model

Mariano Hortal ECMWF

Thanks to: A. Beljars (physics),

E. Holm (humidity analysis)

EWGLAM Oct 2003 2

Noise in forecasts

H+12 Z10 from 28-12-2002 at 12zH+12 from 26-09-2002 at 00z

EWGLAM Oct 2003 3

Linear least square fit interpolation

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EWGLAM Oct 2003 4

SETTLS with LLSI at both departure and arrival in the vertical trajectory computation

H+12 from 26-09-2002 at 00z H+12 Z10 from 28-12-2002 at 12z

EWGLAM Oct 2003 5

Recent developments in the ECMWF physics

Radiation (aerosol climatology) Convection and clouds Clouds and boundary layer Land surface Simplified physics for linear and adjoint applications Orography (MAP reanalysis, turbulent orographic form drag)

EWGLAM Oct 2003 6

Radiation

26R3:•Radiation on a separate grid to save costs (instead of 1 out of 4 points). In T511 model radiation is done on T255 grid.

•New aerosol climatology

•Post-processing of PAR and UV-B

Under development: •RRTM short wave

•McICA: Monte Carlo Independent Column Approximation to represent cloud overlap and inhomogeneous clouds by using different samples of the clouds in the different computational intervals (140 g-points in 16 spectral intervals)

EWGLAM Oct 2003 7

Convection and clouds

26R3:•Clean-up of code and improved numerics leading to better representation of ice fallout

•New cloud base/top algorithm based on entraining plume

•Convection from any layer in lowest 300 hPa

•Revised initiation of convection with perturbed parcels (in T and q) starting from mixed layer properties

•Reduced water load in updrafts through more efficient microphysics

•Increased entrainment

EWGLAM Oct 2003 8

Convection and clouds newold

EWGLAM Oct 2003 9

Convection and clouds

EWGLAM Oct 2003 10

Clouds and boundary layer

•A statistical cloud scheme based on variance of total water is under development

•Moist boundary layer mixing scheme is nearly finished (better

stratocumulus)

EWGLAM Oct 2003 11

Land surface

•Fully implicit tile coupling with less noisy results for the tiles with small fraction

Tiles:• Water• Ice• Wet skin• Low vegetation• Exposed snow• High vegetation• Snow under vegetation• Bare soil

EWGLAM Oct 2003 12

Land surface•An Extended Kalman Filter (EKF) has been developed for soil moisture analysis (as part of the EU project ELDAS).

•EKF can assimilate SYNOP-T/RH, Meteosat heating rates, and microwave brightness temperatures

Single column simulation for MUREX (France), 1. Control with no data assimilation, 2. EKF with microwave Tb 3. EKF with SYNOP T/RH, 4. EKF with surface heating rates

EWGLAM Oct 2003 13

Physics in relation to data assimilation

•Linear and adjoint of radiation code has been developed and is currently under test

•Simplified cloud and convection schemes have been developed for linear and adjoint applications

•Experiments are under way to evaluate assimilation of microwave rain products and brightness T in rainy areas via 1DVAR of TCWV which is assimilated in 4DVAR

•TRMM precipitation radar is used for verification

EWGLAM Oct 2003 14

Physics in relation to data assimilation

TRMM-PR

assim. of TMI Tb

assim. of TMI-rain rate

first guess

EWGLAM Oct 2003 15

Orography: MAP reanalysis

• Reanalysis with all the additional MAP data is available

TCWV from GPS 21-10-1999

TCWV from MAP reanalysis, T511

TCWV from operations 1999, T319

EWGLAM Oct 2003 16

New scheme for turbulent orographic form drag•Alternative to effective roughness length concept•Drag is distributed in vertical and implemented on model levels (Brown and Wood, 2003)•Scales between 5 km and 10 m are represented by this scheme •Universal orographic spectrum is assumed to account for scales smaller than 5 km•Standard deviation of orography at scales between about 10 to 2 km is used to drive the scheme (from 1 km data base)

Comparison of orographic drag and turbulent surface drag (from vegetation) from new scheme with fine scale model results. Expressed as drag coefficient versus terrain slope.

EWGLAM Oct 2003 17

Nonlinearities in the humidity analysis

Humidity is bounded from below (>0) and restricted close to saturation by condensation.

Analysis increments behave asymmetrically at different levels of relative humidity.

A new humidity analysis accounts for this through nonlinear flow-dependent change of variable,

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EWGLAM Oct 2003 18

Some humidity analysis results

With a better background error description, better use is made of humidity observations.

An example is given by HIRS-12 humidity sensitive radiances.

The new humidity analysis (bottom) has removed unrealistic outliers in the background error description.

This results in better humidity forecasts.